ROS2+Cognipilot Complexity

While anyone can build the MR-B3RB, and get it to perform the basic function as described here, further meaningful development will at minimum require some knowledge of ROS2. Below are some suggested training websites to learn about ROS2. Fundamentally B3RB is designed to be a Linux based ROS2 based robotic system with an attached real time control microcontroller. The default configuration uses Ubuntu Linux to run ROS2, as well as Zephyr RTOS + Cognipilot. Cognipilot provides the infrastructure in Zephyr to provide transparent and efficient communications to ROS2, Manage Sensors and Actuators in real time, and host the actual control system algorithms for the vehicle. Even more involved is the development of control algorithms themselves. You do NOT need to become a controls theory expert to use B3RB or any of the other pre-configured vehicle models in Cognipilot, but be aware of the following: The control algorithm software is developed externally, synthesized and then hosted by Cognipilot which is a key feature of Cognipilot Cerebri module. Control Algorithms can be simple or state of the art Model Predictive Control (MPC). Currently B3RB uses modern Lie group MPC theory. Refer to the Cognipilot documentation for more details on this if you are interested in diving deeper. Note also that the same MR-B3RB hardware *can* support any other Linux or RTOS software, but in this GitBook the configuration of ROS2 + Zephyr is the focus robotics enablement.

Suggested ROS2 study resources

ROS2 is an entire subject to study on it's own. In order to be successful in further development, it is strongly suggested you spend some time studying ROS2 fundamentals. There are many resources publicly available for this. Below are only a few.

ROS2 Fundamentals

Udemy or other types or courses provide "completion certificates" a few examples are:

NAV2 module in ROS2 training

To learn about how to run a the robots you will want to take:

Udemy ROS2 NAV2

The Construct - ROS2 NAV2 Navigation

ROSCON

ROSCON is an highly recommended in-person conference and a great way to jumpstart your understanding of the latest development in ROS2. If you have the opportunity to attend it is an excellent conference experience.

The Gitbook documentation is updated regularly. Supportive feedback is welcome: iain.galloway@nxp.com

Welcome to the MR-B3RB Guide

We hope you are ready to embark on an exciting journey into the world of robotics. Meet MR-B3RB – your very own robot Buggy that you build from the ground up. Even though the the B3RB is toy sized, it represents a complete generic representation of a heterogeneous ROS2 enabled robotic platform with real time processors and model predictive real time control. This guide will walk you through the steps to prepare the hardware and the starter software. Please note this is an ADVANCED system, and a background in, or desire to learn ROS2, Linux, and Real Time Operating Systems is a pre-requisite in order to be successful in further development on the platform.

What is MR-B3RB?

MR-B3RB stands for "Mobile Robotics - Buggy 3 Revision B." It's a mobile robotics platform designed to ignite your curiosity and expand your understanding of robotics, programming, and engineering.

MR-B3RB-Mhas the following features:

• Embedded Linux Computer

  • Running Ubuntu POC and ROS2

  • Wireless Connectivity

Why Build MR-B3RB?

• Hands-On Learning: Dive into the practical aspects of robotics, electronics, and programming.

• Skill Development: Sharpen your critical thinking, creativity, and technical skills.

• Fun and Engaging: Experience the joy of building and bringing your own robot to life.

What You'll Find in This Guide

• Step-by-Step Instructions: Detailed, easy-to-follow steps to assemble and program your MR-B3RB.

• Visual Aids: Diagrams, images, and videos to guide you through each stage of the process.

• Troubleshooting Tips: Solutions to common issues to ensure a smooth assembly experience.

Let's get started on this exciting adventure and bring your MR-B3RB to life!

Upper and Lower Chassis

Here we distinguish between the B3RBs lower & upper chassis:

Lidar Arch

This is the assembled buggy minus the top cover. The "bridge" with the lidar module may be referred to as the top plate, the top arch, Lidar arch or the lidar plate:

You will notice that throughout this guide, we use these names. At least now you know what we mean by it.

We will now mount the NavQPlus and the MR-CANHUBK344 to the metal top plate. Follow the steps in the next two sections. In the end, the top plate assembly should look like this:

There are a variety of NXP Mobile Robotics enablements that each have their own GitBook doc as well as reference and product pages on NXP.com. You may want to review some of these other GitBooks to find more detail about specific boards used in the B3RB or boards which could interface with the B3RB:

• : Quick reference and index for all our mobile robotics solutions.

• NavQPlus: i.MX 8M Plus companion computer for mobile robotics

• : NXP Buggy3 Rev B platform using NavQPlus and MR-CANHUBK344

• : The orginal Drone competition with links to Drone & rover dev. kits, with FMUK66 vehicle management unit, and now the MR-VMU-RT1176 vehicle management unit.

• : Autonomous model car competition for students.

• : Small form factor CAN-FD to 100BASE-T1 ethernet bridge.

• : CAN-FD node for mobile robotics applications.

• : Battery management system (3-6 cells).

• : 100BASE-T1 ethernet adapter.

This guide is designed to help you quickly understand and effectively use the MR-B3RB platform. Whether you're a beginner or an experienced developer, you can tailor your experience by following the structure below:

1. For Beginners:

If you're new to the MR-B3RB platform or its components, we recommend starting from the beginning and working your way through each section in order. The guide is organized sequentially, with foundational concepts explained first, followed by advanced topics.

Are you unfamiliar with some of the NXP systems? Please check out the section to learn more about the variety of compatible robotics boards.

2. For Advanced Users (Topic-Specific Exploration):

Experienced users looking for specific information can jump directly to the section they need. Each section is designed to be self-contained, so you can explore topics independently without needing to read the entire guide.

3. Code Examples and Exercises:

Throughout the guide, you'll find code snippets, examples, and exercises. These are marked clearly and are essential for hands-on learning. We encourage you to replicate and experiment with these examples to deepen your understanding.

4. Notes, Tips, and Warnings:

Look out for highlighted notes, tips, and warnings. These callouts contain critical information, best practices, and potential pitfalls that can save you time and effort.

5. External resources:

Some sections include links to external resources, interactive diagrams, or tools. These are designed to enhance your learning experience, so don’t hesitate to explore them for additional context.

Check and Adjust motor gear meshing

B3RB specific abbreviations/glossary

Ackermann Steering:

A geometrical arrangement in vehicles ensuring all wheels follow concentric circular paths while turning, allowing inner wheels to turn sharper than outer wheels, thus reducing tire slip and wear. The B3RB uses Ackermann steering geometry.

CAN Bus

Controller Area Network Bus: A robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer. The NavQPlus and the MR-CANHUBK344 both have CAN bus ports. By default nothing is attached, but you could attach things like Servos, motor controllers, GPS if they had a CAN bus interfaec. The MR-UCANS32K1SIC is a small board that would allow for development of CAN peripherals.

CogniPilot:

The software platform used in MR-B3RB to enable autonomous navigation and control, integrating sensor data and executing navigation algorithms.

GPS

(Global Positioning System): A satellite-based navigation system used in MR-B3RB to provide accurate position and timing information.

IMU

(Inertial Measurement Unit): A device that measures and reports a robot's specific force, angular rate, and sometimes the magnetic field surrounding the body, aiding in navigation and orientation.

Kalman Filter: An algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, to produce estimates of unknown variables that tend to be more accurate than those based on a single measurement alone.

LIDAR: Light Detection and Ranging, a remote sensing method used in MR-B3RB for measuring distances and creating detailed maps of the environment.

MR-CANHUBK344: A central hub in the MR-B3RB system used for managing CAN (Controller Area Network) communications between different modules.

NavQPlus: A development platform used in MR-B3RB for advanced computing and sensor integration, including cameras and GPS. PWM (Pulse Width Modulation): A technique used to control the power supplied to electrical devices, crucial for motor speed control in MR-B3RB.

QDEC (Quadrature Decoder): A system used to interpret signals from rotary encoders, providing precise measurements of wheel rotations in MR-B3RB.

RGB LED: A light-emitting diode that can emit red, green, and blue colors, used in MR-B3RB for visual status indicators.

ROS2 (Robot Operating System 2): An open-source framework for robot software development, providing tools and libraries for building and controlling robots like MR-B3RB.

SLAM (Simultaneous Localization and Mapping): A process by which a robot or device constructs a map of an unknown environment while simultaneously keeping track of its location within that environment.

ToF (Time of Flight) Camera: A depth sensor that measures the time it takes for a light signal to return after being reflected off an object, used in MR-B3RB for obstacle detection.

General Robotics Glossary Autonomy vs Automation

- Automation: Derived from the Greek word "automaton," meaning something that acts by itself. Refers to machines repeating the same motion or tasks without human intervention.

- Autonomy: The capability of a system to govern itself and make decisions independently, operating under its own set of laws.

Robot vs Vehicle

- Robot: From the Czech word "robota," meaning forced labor. A machine that operates automatically or via remote control to perform tasks.

- Vehicle: A device designed for transporting people or cargo. (Despite this, the B3RB may still commonly be referred to as a type of vehicle)

Robotic System: A combination of a robot, its environment, supporting infrastructure, other machines, and humans interacting with it.

AMR vs AGV

- AMR: Autonomous Mobile Robot, capable of navigating and making decisions independently.

- AGV: Automated Guided Vehicle, follows predefined paths or instructions.

Agent and World vs Controller and Plant

- Agent and World: Conceptual framework where the agent (robot) interacts with the world (environment).

- Controller and Plant: The controller directs the plant (mechanical system) to achieve desired outcomes.

Estimate and Belief

- Estimation: The process of transforming sensor data into actionable information such as position, orientation, and velocity for the robot.

- Belief: The robot's internal representation or estimate of its current state based on the processed data.

PID Controller (Proportional-Integral-Derivative Controller): A control loop mechanism used in industrial control systems, employing feedback to maintain the desired output of a system.

Waypoint Navigation: A navigation method in which a robot or vehicle follows a series of pre-defined points, or waypoints, to reach its destination.

MR-B3RB

The lower chassis comes partially assembled with:

• the side skirts attached

• the side plastic attached

• the PDB partially wired

• and the LED lighting installed and wired.

Lower chassis out of the box.

Remove top plate screws and side skirt screws

Remove screws that hold on the side plates and also the screws that hold on the top plate.

Use a hex screwdriver or Allen Key and remove all top screws securing the top plate to the metal frame and carefully set them aside.

Upper Chassis assembly

The following pages describe the mechanical assembly of the MR-B3RB-M.

Pre-assembled Lower Chassis

Note that the lower chassis of the latest version of MR-B3RB-M should be partially assembled as follows:

• Front and rear "bumper" plastic

• PDB (power distribution board) installed

• LED lighting installed and wired to PDB

These instructions are now updated for the production version of the MR-B3RB. If you have a pre-production version, please see or the previous version of the document.

Standoff for LIDAR arch stability

There is a black (or orange) 3d printed plastic standoff post which also protect the cable.

First chose option A (Preferred) or B

Option A: Dual Lock mounting the NavQPlus on the metal frame (Preferred)

Attach the NavQPlus camera to the front plastic mount.

The camera housing included with the NavQPlus mounts to the front "GoPro" style mount on the front plastic:

You must use the screw and bolt that included along with the original camera mount. (This is from the white plastic mount included with the NavQPlus)

The camera flex cable should come out the back of the NavQPlus and loop over top of it. Then route under the lower edge of the front bracket. and up into the camera module. The final setup should look like this:

Front and rear plastic

Screw the front and rear plastic to the top plate using two M3x5 screws from the bottom

The camera flex cable should already be attached to the front plastic.

Introduction

The RGB LEDS communicate using a SPI-like communication which is modified in that it is unidirectional. The data and power for the LEDs is supplied by a STEMMAQT type connector the PDB, and the SCL SDA (SPI) lines have a second wire connector which attaches between the PDB and SPI port on MR-CANHUBK344

RGB LED wiring

The following image shows the LED lights setup with the left side representing the rear and the right side indicating the front of the car. This is pre-assembled. If for some reason you need to re-create these connections, you should know that it is a daisy chain of STEMMA-QT type connectors, and that there is a marked IN and OUT connector on each of the LED light bars. The connections are from PDB -> IN(rear) -> out(rear) -> in (front)

Use the seven-pin JST-GH wire depicted in the picture below to connect from PDB to MR-CANHUBK344

1. Connect one end of the wire to SPI pin of the PDB.

1. Connect other end to the SPI2 of the plastic case of the MR-CANHUBK344:

Introduction

MR-CANHUBK344 is the real time controller board for the robot. After successfully attaching the NavQPlus, the next step is to install the MR-CANHUBK344 evaluation board.

Install the MR-CANHUBK3-ADAP on the MR-CANHUBK344

Included in the kit is a CANHUB ADAP board. This board has IMU (Inertial measurement Unit) components on it such as Accelerometer, Gyro, Magnetometer, as well as specific connectors for GPS and other interfaces. Attach it to the CANHUBK344 as shown below.

Assemble MR-CANHUBK344 onto top plate

The MR-CANHUBK344 board should be attached in the highlighted holes of the following image. Reuse the M3x5mm screws that were previously removed from the side skirts. These M3x5mm screws should be used to screw in from the bottom side.

Upon completion, the entire assembly should appear as follows:

Introduction

The kit may include either or both an ARMING board and/or a GPS module. The GPS module in addition to being used for GPS, the it does also include a arming/safety switch, LED lights and a beeper. Generally if you have a GPS, it is preferred to use that rather than the ARMING board.

PX4 Arming Board vs GPS

The arming board will provide the same beeper and arming buttons. However it does not include a compass component.

Install M10 GPS module

If provided in your kit, please install the GPS and GPS post mounting, The the pieces are listed in the page.

GPS parts

GPS Base installation

There is a set of screws that comes with the GPS unit. Use the 4 longer screws and Nylock Lock Nuts to attach the base mount.

It should be placed in this furthest back position:

GPS Mast installation

Attach the mounting mast rod and fasten it with one of the smaller two screws left. At this time only tighten the screws loosely as you will need to rotate align and remove the mast before completion.

Attach the top mount with the remaining screw. Keep it also only loosely tightened. It should look like this when completed:

Attach the M10 GPS module to the mast

Locate the M10 GPS and the 3M double tape.

Attach the double tape in the center of the top mount.

Align GPS facing forward

Carefully align the GPS in the center of this tape. Ensure the arrow on the GPS module is facing forward. The cable of the GPS should be zip tied so it stays very close to the GPS mast in order to not obstruct the LIDAR sensor.

Trim any long cable ties with side cutters.

The MR-B3RB is versatile and can support several network wiring configurations. There are also several optional communication bus connections. This section will serve to show the BASELINE connections. We will also attach cables that may not be used, but should stay with the B3RB for future expansion or debugging.

Baseline B3RB wiring intent

Introduction

The NavQPlus and MR-CANHUBK344 communicate to each other using 100Base-T1 Two wire ethernet .

Introduction

The Quadrature decoder (QDEC) cable connects from PDB to MR-CANHUBK344. Quadrature signals are coming from the encoder on the motor itself. The PDB is then used to interface between the two different cable types. QDEC signal provides measured information on how many revolutions the motor has made, and therefore how far the robot has travelled. This can then be used in the control system as an input. See here for more information about Quadrature encoding.

QDEC (Quadrature Decoder) Cable

This cable is crucial for calculating the odometry, speed and direction of the robot car. There are six black wires and one red wire in it. The cable should look like this:

One end of the cable must be attached to the QDEC out pin on the PDB:

And the other end must be attached to the following pin on the MR-CANHUBK344:

(DRAFT)

Block Diagram of the NavQPlus

<todo> insert a block diagram and or photo of wiring. Image below may be helpful

<todo > add schematic block diagram of how everything is connected

Introduction

There are two 5 pin JST-GH cables that provide battery power to the MR-CANHUBK344 and the NavQPlus. They are 5 pins, with no wire in the center position. Two wires are battery voltage+ and two wires are battery voltage-. Be sure to limit the voltage applied at the battery to <20V or the specified ratings for any boards plugged in.

Long and short power cable

• There is one long and one short power cable included in the kit.

• Connect is the LONG power cable from the MR-CANHUBK344 to one of the the Power Distribution Board Pout connectors.

• The shorter length power cable can be similarly connected to the NavQPlus

Steering Servo PWM cable connection

The image illustrates how a servo motor is connected to the PDB (Power Distribution Board). It shows three distinct wires: the red wire is +5V positive voltage supply, the brown wire is the ground connection, and the yellow wire carries the control RC-PWM signal from the microcontroller (MR-CANHUBK344).

Power cable from PDB to MR-CANHUBK344

These cables connect to any of the 4 pin Pout connectors on the PDB. All Pout connectors are the same, but some may be closer and provide a better location. Choose one that makes your wiring tidy without overstretching the cable.

And the other end connects to the power input (AKA VBat) of the MR-CANHUBK344

Introduction

The GPS module is primarily used to provide the Magnetometer, sound and SAFETY button for the system. Not all systems will use the GPS localization functionality. The software however is capable of using the use of GPS position data for navigation outdoors.

M10 GPS connection

The M10 GPS cable attaches to the MR-CANHUBK344 as shown below

Power Cable

Power cable from PDB to NavQPlus

It is a four-wire cable having two red and two black cables representing VCC and ground respectively. Firstly, connect one end of the cable to any of the pout terminal on the PDB.

Then connect the other end on the following connector of the NAVQPlus.

BaseT1 Ethernet wiring between NavQPlus and MR-CANHUBK344

This is also explained here:

Lidar connection

<TODO> refer to the mounting of the LIDAR base

The cable necessary for connect the NavQPus to the LIDAR-STL-27 is the number one in .

A closer view of this cable:

The Lidar used is the following:

You should connect the smaller end of the cable to the Lidar and the bigger end to the UART3 Serial port of the NavQPlus:

Thse are all the connections available for NavQPlus:

<TODO >

• note on CAN

• note on console

• note on Ethernet

(optional) Tie wrap wires

After connecting all the cables, proceed to attach the metal board frame to the robot car using the screws you removed at the beginning of this tutorial:

Front Plastic Shield with Mount for Camera

Please attach the plastic shield with the camera housing to the robot's front using M2.5 pan head Philips Self-Tapping screws, which are located in this box provided:.

For reference, a picture of the screws is displayed here: <<<TODO - these are not the correct screws. They should be flat head (tapered head> screws. Take picture and add here>>>

The mounting must look like these pictures:

Back Plastic Shield

And the attach the back plastic shield of the robot with the same screws:

The antenna depicted in the image must be handled with utmost caution and preserved within the protective plastic enclosure.

CAN Termination network

CAN Networks typically requre proper termination at both ends of the bus in order to function correctly. Many of the boards used will include this termination optionally on board. Additionally many of the NXP boards use CANSIC (Signal Improvement Can Phy) which is more resiliant to mis-matched or incorrect termination. Included in the kit is also a CAN termination board. By plugging in the can termination to the second connector on the MR-CANHUBK344 or NAvQPlus it will add termination network to that end of the circuit. This board also includes a USB input and solder pads for instances where power is to be supplied into the CAN bus using this device. In the MR-B3RB this power injection is NOT needed as 5V power is already supplied.

Introduction

The MR-CANHUBK344 sends PWM signals to the Motor controller and also to the Servo. These are standard RC Model type PWM connections. In order to facilitate keeping the signals in the correct order they are routed and consolidated onto a single cable and small "XDHP" connector board. It is still quite important to get the XDHP connector positioned correctly on the PWM header of the MR-CANHUBK344

Thw PWM/XDHP wire connection should look like as depicted in the following picture:

PWM signals wiring to MR-CANHUBK344

The cable carrying PWM signals between the MR-CANHUBK344 board, and the Power Distribution Board should look like as shown in picture below. It is a seven wire interface which carries multiple PWM signals and has a VCC line and a ground.

There is a small "XDHP" adapter board to fit on the PWM pin-header of the MR-CANHUBK344 board. This is provided in the kit and show in the image above

XDHP connection on PDB side

The one end of the PWM cable is connected on the XHDP pins on the PDB:

The other end of the cables having the xHDP adapter on it is mounted on the first three columns(Three pairs of three pins) of PWM pins which represents PWM0, PWM1 and PWM2 positions of the MR-CANHUBK344 respectively:

XDHP (PWM) connection on MR-CANHUBK344 side

Installation of the XDHP adapter board and cable is most easily done when the cable and connector are conected together first. Then gently bend the wires at a 90 degree angle. Push the XDHP adapter onto the CANHUBK344 pin headers. The images show XHDP adapter is mounted on the first three columns (Three pairs of three pins) of PWM pins. This corresponds to PWM0, PWM1 and PWM2 positions of the MR-CANHUBK344 respectively.

Introduction

This is one of the last steps. You may still want to check everything over to avoid having to insert and remove screws

Preparation

In previous steps you should have

A Note about screws

There are several options for the screws to hold on the arch:

Form your own threads by hand (carefully)

The Lidar arch attaches with screws into the plastic front and rear covers. Ideally M3x5 Socket head cap screws are used, but the plastic is not threaded making it diffocult to insert the screws. With care an patience you can cut your own threads by pushing consistently while turning the screw, then backing off and cleaning the debris off the screw threads. Repeat this several times until the screw goes in all the way.

Use a Thread Tap

Alternatively if you have access to an that will very quickly and easily form threads.

Use the self tapping screws from the Buggy spare screw kit.

These are small self tapping black screws from the Buggy spare parts kit. While somewhat small, they will work to hold the arch in place.

When completed your Lidar arch should look something like this:

Connection: SPI wire for LED

Connection: 100BaseT1 Ethernet

Connection: QDEC

Connection: PWM Cables

Connection: PDB power to NAVQPlus

Connection: PDB power to CANHUB

Introduction

Typical battery and battery connection

There are two locations where on board batteries could be located after being connected

Battery on Mezzanine level

1) On the "mezzanine" level of the frame and

Battery on Lower level of Frame

2) On the lower part of the the lower chassis.

Since the mezzanine level may be used for additional electronics in the future, we will refer only to the removeable battery location on he lower chassis.

Notes on Securing the battery

The exact method of securing the battery is dependent on the user preferences.

• There is a battery strap included in the kit. This could also be used to strap to the upper/mezzanine level of the metal frame.

• You may wish to remove the small plastic battery tray frame that is already installed in the kit in order to free up additional space.

• A foam piece can be used to wedge between the underside of the battery and the lower chassis in order to prevent any movement. This wedges the battery "up" against the underside of the mezzanine level.

Battery Power switch

Latest versions of MR-B3RB-M include a power switch mounted under the front edge of the B3RB. Toggle it to the on or off position as desired.

LiPo Battery Specification

Typically we use off-the-shelf LiPo battery pack similar to what is used in RC airplanes and Quadcopters.

The battery should have the following specifications:

• LiPo 3s (Three Cell) 12V nominal voltage (10-14V)

• 2000-3000mAh

• XT60 connector with balance leads

• Dimensions

  A) 75mm L x 34mm W x 26 H (short and stubby)

  B) 100-110mm L x 35mm W x 22-26mm H (longer format)

  • Other dimensions are possible. Ensure the battery chosen fits the compartment area,

Links to sample batteries

Below are links to some example batteries. THIS IS IN NO WAY an endorsement of these specific batteries, only a link so you can see more detail about the types of similar batteries that could be used:

Example Stubby / Shorty type battery pack

Zeee 3S 2200mAh Lipo Battery 11.1V 50C Shorty Pack Battery with XT60 Plug for RC Car Truck RC Vehicles Boat Drone RC Airplane Quadcopter Helicopter FPV Racing Hobby Models(2 Pack)

HOOVO 3S Lipo Battery 2200mAh 80C 11.1V Shorty Lipo Battery Pack Softcase with XT60 Connector Compatible with Drone RC Airplane Helicopter Quadcopter FPV RC Car,2 Pack

Example Longer/larger format battery pack

LiPo Battery charger

You must use a LiPo battery charger to safely charge the battery. There are very inexpensive ones available that will charge using the cell termination connectors at the expense of them being quite slow to charge. Many other types of chargers exist. When choosing a charger consider that this is a safety issue and overcharging or improperly charging can be dangerous and result in a fire.

There are many excellent LiPo battery chargers available. ISDT makes several high-end charges like the following: (This is an example, and not a specific recommendation)

Battery monitor usage

MR-B3RB units have a power monitor built into the PDB board. This will tell you the total pack voltage and individual cell voltage. It will alarm when the cell voltage goes too low. There is an optional BMS that can interface with the B3RB. It provides advanced battery monitoring capabilities.

Battery Alarm

LiPo batteries shoudl never be over-discharged. The PDB battery monitor will measure the battery voltage level, and properly running software and control software will alert the user if tbe battery is low. As an extra backup, a small battery alarm board is included, that can be attached to the battery CT leads directly. This is recommended and can save you from over discharging during development or when you may get distracted (i.e. at a tradeshow or seminar) The alarm is connected as shown in the attached photo. While it's usage is mostly self explanatory, you can learn more via YouTube tutorials such as this one:

LiPo Battery charger

You must use a LiPo battery charger to safely charge the battery. There are very inexpensive ones available that will charge using the cell termination connectors at the expense of them being quite slow to charge. Many other types of chargers exist. When choosing a charger consider that this is a safety issue and overcharging or improperly charging can be dangerous and result in a fire.

There are many excellent LiPo battery chargers available. ISDT makes several high-end charges like the following: (This is ONLY an example, and not a specific recommendation)

Battery monitor usage

MR-B3RB units have a power monitor built into the PDB board. This will tell you the total pack voltage and individual cell voltage. It will alarm when the cell voltage goes too low. There is an optional BMS that can interface with the B3RB. It provides advanced battery monitoring capabilities.

Battery Alarm

LiPo batteries shoudl never be over-discharged. The PDB battery monitor will measure the battery voltage level, and properly running software and control software will alert the user if tbe battery is low. As an extra backup, a small battery alarm board is included, that can be attached to the battery CT leads directly. This is recommended and can save you from over discharging during development or when you may get distracted (i.e. at a tradeshow or seminar) The alarm is connected as shown in the attached photo. While it's usage is mostly self explanatory, you can learn more via YouTube tutorials such as this one:

Battery monitor

MR-B3RB units have a power monitor built into the PDB board. This will tell you the total pack voltage and individual cell voltage. It will alarm when the cell voltage goes too low.

Advanced BMS

There is an optional BMS that can interface with the B3RB. It provides advanced battery monitoring capabilities.

Battery Alarm

LiPo batteries should never be over-discharged. The PDB battery monitor will measure the battery voltage level, and properly running software and control software will alert the user if tbe battery is low. As an extra backup, a small battery alarm board is included, that can be attached to the battery CT leads directly. This is recommended and can save you from over discharging during development or when you may get distracted (i.e. at a tradeshow or seminar) The alarm is connected as shown in the attached photo. While it's usage is mostly self explanatory, you can learn more via YouTube tutorials such as this one:

Bonus feature! The top cover doubles as a work stand. This will keep the wheels up of the ground and can be quite useful while testing. You should add soft tape or foam on the underside of the buggy chassis in order to avoid scratches on the top cover.

History

MR-B3RB is short for Mobile Robotics - Buggy3 Revision B. This is the second revision to a robotic vehicle called . Some people didn't like calling a product "buggy". So even though Buggy3 is a brave name, we decided to instead make it MR-B3RB as it is a nice and friendly robot like R2D2.

We took lessons learned from that platform and applied them as an upgrade for 2024.

Schematics as per production build.

The PDB serves two main functions: 1) Takes in Battery voltage and provides FUSED RAW battery and regulated 5V power out.

2) a connector interface converter board.

Overview

Cognipilot software module operate across multiple processors in order to form a complete system:

• CogniPilot Electrode - Runs on PC host groundstation with Linux/ROS2

MR-B3RB is intended as a research/development platform. That means we expect the end user to compile and install your own software based on opensource references. Example software configurations are described in the following sections.

Most of the sofware ecosystem examples will requre using a native Linux PC. It may be possible to use a Windows PC running WSL or a virtual Linux machine like VMware, Virtual Box, but this is not supported in this documentation. Generally Roboics uses ROS2 and a correcsponding LTS version of Ubuntu. Other configurations may work, but are not supported in this documentation.

Block Diagram: Power Distribution Board

The PDB (Power Distribution board) is where both power enters from the battrey , and also provides a number of connector "translations" to match the motor and LED lighting. Specialized connectors on the motor and encoder to translate to the Dupont-style or standard DroneCode connector pinouts. It should be noted that the block diagram above does not show ALL the power distribution connections, which are as follows:

• Battery input through a fuse

• Battery voltage and current measurement through the INA226

• 3x Battery voltage outputs on 5 pin JST-GH for NavQPlus, MR-CANHUBK344, Extra

• 5V regulating supply for LED lights, and powering PWM servo rail on MR-CANHUBK344 and therefore the Servo itself.

• PWM signals are consolidated into a single XHDP connector for ease of connection.

Block Diagram: GPS Module

The GPS combines UART, I2C for Compass, and GPIO for switches, LED, and Beeper into a single large DroneCode standard connector.

Block Diagram: Debugging interfaces

The DCD-LZ interface simply combines SWD and a UART on a single JST-GH Dronecode connector. Depending on your kit you may have any of the following debug adapter boards:

• FTDI USB-UART cable and adapter for UART/Console on the NavQPlus

• FTDI USB-UART cable + DCD-LZ adapter for MR-CANHUBK344 DCD-LZ interface

• In some systems you will find NeuralProbe board with USBC interface and connectors for UART/Console AND DCD-LZ interface. This board includes a USB-UART converter and also includes a button that will toggle the RST pin on SWD/JTAG interface. There is a 3rd interface on this board for Pixhawk V6X debug+uart connectors (not used here, used with NXP MR-VMU-RT1176)

CogniPilot introduction

CogniPilot is a (newer) opensource vehicle control software framework that sits cleanly on top of the Zephyr RTOS. This hosts an example Model Predictive Control real-time vehicle controller software which works with MR-B3RB kits. Other software or control algorithms may also be used. but is out of scope for this section of the documentation. Cognipilot is the default reference example control software.

Note that EVEN when not using the full capability of CogniPilot, the framework still includes many software modules, high level drivers, communications methods and related PC tools and setup that makes other less demanding uses (such as NXP-CUP) much easier. The framework is there and can be used as much or as little as needed.

Zephyr and CogniPilot

Zephyr RTOS has build targets for MR-CANHUBK344 and MR-VMU-RT1176 which can be used as part of the real-time controller and IMU for MR-B3RB. In various versions of MR-B3RB kits these boards may already be included.

CogniPilot info

CogniPilot's claim to fame is that the control system software component is synthesized as a module from popular control software called CasADi. CasADi is popular with control systems engineers and researchers and allows the decoupling of the control theory, simulation and mathematical proofs from the actual code that implements the particular controller math. This approach helps with ensuring safety and robustness, while also supporting rapid innovation

CasADi

CasADi is an open-source tool for nonlinear optimization and algorithmic differentiation.

It facilitates rapid — yet efficient — implementation of different methods for numerical optimal control, both in an offline context and for nonlinear model predictive control (NMPC).

CogniPilot Cerebri module

CogniPilot is a group of software modules making up the vehicle control system. More details of what each of the modules does is available and explained in more detail on the project website.

Cerebri represents the CogniPilot control-system software module and is named similarly to a human brain cerebellum, which "processes and regulates signals between other parts of your brain and body, and is involved in coordinating functions of your body (for example, walking)." The synthesized code from CasADi, or code representing the control theory-module for the particular vehicle intended, plugs into CogniPilot's Cerebri module. The control system for the vehicle type is a swappable module, it can define control functions or approaches that relate to a ground vehicle vs a multicopter, vs a winged vehicle. You then separately provide a hardware description file for the specific vehicle characteristics.

Example:

One of many control theories could be used to control an Ackermann steering car. The specific control theory is built in CasADi. Code is then synthesized and put into Cerebri for execution. The control theory was for a generic Ackermann vehicle type. The hardware description file defines the power of the motors, the size of the vehicle and wheels, the placement of all these wheels. You could theoretically have an Ackermann vehicle where the steering is misaligned with the drive wheel thrust. This same control software works for a passenger car or a toy car since the vehicle size and power that gets defines independently. A different synthesized control theory would be loaded to control a multicopter. The hardware definition would control the arm lengths, the number and orientation of the motors, and the thrust from the motors.

CogniPilot information

There is much more detail and information about the design and structure of CogniPilot here:

The developer guide for CogniPilot can be found here:

Introduction

Prepare MR-CANHUBK344 real-time vehicle controller

Follow this section of CogniPilot to prepare Cognipilot-Cerebri on MR-CANHUBK344:

NEW:

NEW:

This will:

1. Update MR-CANHUBK344 with the Zephyr+Cognipilot-Cerebri image. (Cerebri is the application, Zephyr is the RTOS. They are flashed simultaneously using a prepared image.)

First connect MR-CANHUBK344 to J-LinkEDU Mini

You need to follow this guide to correctly flash Cerebri onto the board:

Software Setup for MR-CANHUBK344

Next Steps

At ths point you are ready to use the MR-B3RB.

You can log into the NavQPlus and even into the MR-CANHUBK344 running CogniPilot/Zephyr

You can run ROS SIL or "real hardware" examples using RVIZ or Foxglove as a control station.

The vehicle is capable of being safely armed through several steps and autonomously navigating to a position and pose as specified/pointed to on the control station software.

Execution

Software Procedure

MR-CANHUBK344

When booted, MR-CANHUBK344 should display the following CogniPilot logo and welcome screen on the console.

Within a few seconds, the red light on the T1-Ethernet port on both the boards should light up.

NavQPlus

Links

The developer guide for CogniPilot can be found here:

NEW

Introduction

Prepare your Linux development PC

Please start with an Ubuntu Linux install 22.04 or newer.

Follow this section of CogniPilot to prepare your Linux development PC with ROS, Zephyr and CogniPilot development tools

NEW Ubuntu Linux 24.04

This will:

1. Setup ssh keys and gpg keys for git access

2. install Git

3. Install ROS2

Next Steps

At this point you have configured a Linux PC for development. Follow the remaining subpage steps for guidance to get the B3RB (CANHUB-K3 and NavQPlus ready) to be updated. Note that the next section to refer to in the CogniPilot will be

NEW

Introduction

The full robotics reference design experience on MR-B3RB relies on the Linux NavQPlus companion computer working in concert with the real time controller MR-CANHUBK344. CognipPilot is the preferred opensource example framework that works hand in hand with ROS2 to provide a fully robotic vehicle, and sets up and configures the majority of the associated host companion computer, and development PC tools. The CogniPilot based "system" is therefore more than just the Cerebri real time vehicle control module.

Installation and setup overview

A) Prepare your Linux development PC

Follow this section of Cognipilot to prepare your Linux development PC with ROS, Zephyr and Cognipilot development tools :

NEW

B) Prepare NavQPlus

Follow this section of to prepare Cognipilot-Cranium on NavQPlus :

NEW

C) Prepare MR-CANHUBK344 real time vehicle controller

Follow this section of CogniPilot to prepare Cognipilot-Cerebri software on MR-CANHUBK344 :

NEW

NEW

Next Steps

After installation, you are ready to use the MR-B3RB.

• You can log into the NavQPlus and even into the MR-CANHUBK344 running CogniPilot/Zephyr

• You can run ROS SIL or "real hardware" examples using RVIZ or Foxglove as a control station.

• The vehicle is capable of being safely armed through several steps and autonomously navigating to a position and pose as specified/pointed to on the control station software.

Links

The developer guide for Cognipilot can be found here:

NEW

Introduction

Prepare NavQPlus

Follow this section to prepare CogniPilot-Cranium on NavQPlus:

NEW

This will:

1. Flash the EMMC on the NavQPlus with the current Linux Image, using uuu using the USB interface

2. Establish a console connection using one of the three possible methods (USB-UART, SSH,USB-C Gadget ethernet)

3. Connect NavQPlus to a Wi-Fi network and establish an alternative console via SSH over Wi-Fi connection

Links

The developer guide for CogniPilot can be found here:

NEW

Introduction

Introduction

At ths point you are ready to use the MR-B3RB. If you have reviewed the documentation you should now:

• You can log into the NavQPlus console and even into the MR-CANHUBK344 running CogniPilot/Zephyr

• You can run ROS SIL or "real hardware" examples using RVIZ or Foxglove as a control station.

• The vehicle is capable of being safely armed through several steps and autonomously navigating to a position and pose as specified/pointed to on the control station software.

Operation of ROS-CogniPilot

Software Procedure

MR-CANHUBK344

OPTIONAL: When booted, if you have a console connected, MR-CANHUBK344 will display the following CogniPilot logo and welcome screen on the console.

Within a few seconds, the red light on the T1 Ethernet port on both the boards should light up.

Linux Host PC

(The definitive guide is on cognipilot.org !! copied here for convenience only)

• From the command line run

NavQPlus

• Login to the NavQPlus using ssh or serial console.

• Ensure the NavQPlus and Host PC are on the same network

• AFTER starting ROS on the Host PC, THEN on the NavQPlus run

Links

The developer guide for CogniPilot can be found here:

NEW

First take the J-Link EDU Mini, you can find more information here:

Then, get the J-Link EDU Mini. Then, use the cable with a micro USB connector on one end and a USB Type-A connector on the other end.

Then take the and connect it to the J-Link EDU mini:

Please, connect the 10-Pin 2x5 Socket-Socket IDC (SWD) Ribbon cable in the following position to the J-Link EDU Mini:

Next, please pick up the Cognipilot debug adapter:

Next, connect one end of the 10-pin 2x5 Socket-Socket IDC (SWD) ribbon cable to the connector on the Cognipilot debugger. Ensure that the orientation of the connector corresponds to the one shown in the following image:

Finally, connect the other end of the 7 position JST-GH connector to the MR-CANHUBK344. Please, connect it into the pin showed in the following image:

Now, you just need to connectConnect the USB cable to your development computer and also remember to connect power to the Buggy (the LiPo battery to the PDB) in order to flash the MR-CANHUBK344, as the board needs to be connected to the power. Then, you can return here to follow the instructions: .

Connect the MR-Link-MR to the 7 position JST-GH programing connector to the MR-CANHUBK344. Please, connect it as shown in the following image:

Now, you just need to connect the USB cable to your development computer and also remember to connect the LiPo battery to the PDB to flash the MR-CANHUBK344, as the board needs to be connected to the power. Then, you can return here to follow the instructions:

This section is intended as a quick guide to setup the buggy and let it drive either autonomously or manually.

First take the J-Link EDU Mini, you can find more information here:

Then, get the J-Link EDU Mini. Then, use the cable with a micro USB connector on one end and a USB Type-A connector on the other end.

Then take the and connect it to the J-Link EDU mini:

Please, connect the 10-Pin 2x5 Socket-Socket IDC (SWD) Ribbon cable in the following position to the J-Link EDU Mini:

Next, please pick up the DCD-LZ adapt board:

Next, connect one end of the 10-pin 2x5 Socket-Socket IDC (SWD) ribbon cable to the connector on the DCD-LZ adapt board. Ensure that the orientation of the connector corresponds to the one shown in the following image:

The pick the 7 position JST-GH connector:

Finally, connect one end to the DCD-LZ adapt board and the other end of the 7 position JST-GH connector to the MR-CANHUBK344. Please, connect it into the pin showed in the following image:

Now, you just need to connect the USB cable to your development computer and also remember to connect the LiPo battery to the PDB to flash the MR-CANHUBK344, as the board needs to be connected to the power. Then, you can return here to follow the instructions:

The MR-B3RB platform is equipped with a camera connected to the NavQPlus, enabling a variety of functions such as robot visualization, Visual SLAM, and other computer vision and machine learning applications. The Cognipilot package for ROS2 includes an 'ov5645.ini' configuration file with the camera's intrinsic calibration data. This data is crucial for correcting lens distortion and understanding the camera's geometric properties in computer vision and robotics applications. However, this file serves is just an indication, and users must perform a camera calibration after assembling the MR-B3RB robot to ensure a better operation.

Introduction and background

Some cameras, such as pinhole cameras, introduce significant distortion to images. Two major kinds of distortion are radial distortion and tangential distortion.

Radial distortion causes straight lines to appear curved. Radial distortion becomes larger the farther points are from the center of the image. Similarly, tangential distortion occurs because the image-taking lense is not aligned perfectly parallel to the imaging plane. So, some areas in the image may look nearer than expected. In short, we need to find five parameters, known as distortion coefficients.

Extrinsic parameters corresponds to rotation and translation vectors which translates a coordinates of a 3D point to a coordinate system

To find these parameters, we must provide some sample images of a well defined pattern (e.g. a chess board). We find some specific points of which we already know the relative positions (e.g. square corners in the chess board). We know the coordinates of these points in real world space and we know the coordinates in the image, so we can solve for the distortion coefficients. For better results, we need at least 10 test patterns.

In addition to this, we need to some other information, like the intrinsic and extrinsic parameters of the camera. Intrinsic parameters are specific to a camera. They include information like focal length and optical centers. The focal length and optical centers can be used to create a camera matrix, which can be used to remove distortion due to the lenses of a specific camera. The camera matrix is unique to a specific camera, so once calculated, it can be reused on other images taken by the same camera.

Camera calibration example procedure.

After the theoretical background we are going to see how to calibrate the camera on the MR-B3RB robot.

Connect through ssh to the NavQPlus as explained in

Install necessary packages

Install b3rb_camera_calibration package

Start calibration procedure

In one terminal run the following command:

Then open a new terminal and connect throush ssh to the NavQPlus and run:

If you want to see the output yo can run in your host computer:

This will open foxglove and you will be able to select the topic /calibration_camera_feed on the image panel.

You should be able to see something like this.

Calibration procedure

For the calibration process, it's advised to keep the robot stationary and move the calibration pattern to different positions instead. Place it at various angles, because the calibration system requires multiple samples and poses to calibrate accurately.

You will see the 'Continue Sampling' message in the terminal until the calibration process has collected enough samples. After that, the message will switch to 'READY TO CALIBRATE.' Additionally, the 'calibrate' text in the Foxglove image will change to blue, as shown in the image below:

Finish calibration

After the calibration node has collected enough samples, you'll need to open a new terminal window. Then, connect to the NavQPlus via SSH to begin calculating the camera matrix. In this new terminal, execute the following command to start the calibration:

For saving the results please run the following command:

Then you must see a message similar to the following:

Then the calibration has successfully finished, to stop the calibration please run:

ros2 topic pub /calibration_control std_msgs/msg/String "data: 'stop'" --once

View the results

To see the calibration results, first navigate to the cognipilot folder:

Then create a new folder:

And uncompress the file and place the files in this new folder:

The files ost.txt and ost.yaml contain the camera matrix and distortion parameters.

Calibration pattern

You have to print a calibration pattern, this tutorial is going to be done with a 9x6 chessboard pattern, but you can do it with other pattern. This web allows you to choose the one that you prefer:

This is the one used in this tutorial:

Please print it in an A4 mantaining the original size.

Launch Notes for B3RB:

Serial terminal

# serial terminal to NavQPlus

screen /dev/ttyUSB0 115200

Setup WiFi connection

# Setup wifi hotspot on phone.

# same network as host PC

# show local wifi networks, find the one you want

sudo nmcli device wifi # for a text interface sudo nmtui

# Connect NavQPlus Wifi to network

sudo nmcli device wifi connect <network name> password <password>

FoxGlove open connection command

When Foxglove starts, "Open Connection" and type connect to ws://b3rb-xx.local:4242 (replace b3rb-xx with whatever your buggy's hostname is)

SSH Login

# SSH login to NavQPlus

ssh user@mrb3rb

#or

ssh user@mrb3rb.local

ROS2 Launch commands

# FIRST launch Ros2 electrode on host pc

ros2 launch electrode rviz2:=false

# Then launch Ros2 on B3RB

ros2 launch b3rb_bringup robot.launch.py

Set a ROS Domain ID

If there are multiple vehicles being used at the same time on the same network, then you will also need to set a unique ROS_DOMAIN_ID for on both the host LInux machine and the NavQPlus edit your file ~/.bashrc using VIM, NANO or GEDIT

change the line (find with CTRL+W) export ROS_DOMAIN_ID=xxx

where xxx is a unique number from the other robots

Sometimes you just want to start over. It's ok, we all have days like that. I Fyou need afresh cognipilot start, and want to be extra sure there are no leftover dependencies or files you dont' want etc then follow these steps. Keep in mind this is going to erase local changes you may have made to cognipilot files. Note them in advance if you want to re-do the changes afterwards. (for example you may have disabled the battery voltage check in <todo> xxx.conf)

For clean install on your PC

sudo rm -rf /opt/toolchains
sudo rm -rf /opt/zeth
sudo rm -rf /opt/poetry
rm -rf ~/bin/build_*
rm -rf ~/bin/west
rm -rf ~/bin/cyecca
rm -rf ~/bin/docs
rm -rf ~/cognipilot

Then start again with the cognipilot install instructions for the Linux host development PC.

or this link https://airy.cognipilot.org/getting_started/install/#use-cognipilot-universal-installer

Stuck on a previous Gazebo

The instructions above will take care of Gazebo install also. If you happen to know you are stuck on an old version of Gazebo you may want to just try this first. The example below is where gazebo "garden" (gzgarden) is installed, but you want gazebo "harmonic"

DRAFT-DRAFT-DRAFT Connect the MR-Link-MR to the 7 position JST-GH programing connector to the MR-CANHUBK344. Please, connect it as shown in the following image: <todo> update image to show MR-Link-MR <todo> alternatively connect the 10 pin JTAG/SWD ribbon cable connector <todo update photos below

Connect the USB cable to your development computer and also remember to connect power to the Buggy (the LiPo battery to the PDB) in order to flash the MR-CANHUBK344.

Zephyr West : MCU-Link-MR (using pyOCD)

Use this command when programming using the MCU-Link or MCU-Link-MR from Zephyr west tool

The MCU-LINK-MR is an updated version of the MCU-link which includes debug interfaces for robotics including DCD, DCD-LZ, Pixhawk debug large and small, and USB-C to UART console. PyOCD method has to be used when using a or MCU-Link-MR

west flash --runner pyocd

Building, Flashing and Debugging — Zephyr Project Documentation

More detailed official documentation for this is available here. See for default runner to use can be set​​ Then, you can return here to follow the instructions:

(** Add note about how to set network interfaces correctly for DDS CycloneDDS config. when more than one interface exists. This is a ROS configuration and not really Cognipilot.)

Here you find other hw modules (not included in the box) that are cool to expand your MR-B3RB with.

INTRODUCTION

The B3RB can use a TOF distance sensor as a cliff detector and the appropriate software to prevent it from driving off a table, down a stairway or any other "cliff" it may encounter while moving forward. These sensors could also be used pointing in other directions for other proximity detection applications. This tutorial describes how to perform cliff detection on MR-B3RB using TOF VL53L4CD sensor with MR-CANHUBK344 and MR-CANHUBK3-ADAP boards. The example and configuration shown below is with the MR-CANHUBK344 running Zephyr and Cognipilot but is showing the board outside of the installation on a MR-B3RB. When used with a B3RB, the power is supplied in the normal fashion and not with external connectors shown.

Operation Explanation

The Time of Flight VL53L4CD sensor measures distance within the range 1 mm to 1300 mm.

The sample application "samples/sensor/vl53l4cd" polls on the sensor every 1 second and reads the current distance measured from the device. Then it prints the distance on the console (in meters).

ITEMS REQUIRED

SETUP DIAGRAMS

HARDWARE SETUP

This hardware setup shows these boards outside of MR-B3RB on a tabletop. This of course can also be done on the vehicle itself. Simply plug in the sensor and the STEMMA QT cable to the CANHUB-ADAP. The power and other connections do not change from a normal MR-B3RB configuration.

1. Connect hardware components as shown in the block diagram above. The CANHUB-ADAP includes a I2C connector that follows the ADAFRUIT STEMMAQT standard.

2. Attach the MR-CANHUBK3-ADAP board on top of MR-CANHUBK344.

3. Power on the MR-CANHUBK344 board - connect the SYP connector to the MR-CANHUBK344, and the other end of the cable to your bench power supply or any source that could provide 5V DC.

SOFTWARE SETUP

Setup West Workspace

Building and Flashing

RESULTS

Get the shell of MR-CANHUBK344.

The shell should display output as:

How to use RVIZ2/ROS2

1. Connect the buggy with the j-linkcable to your laptop. Connect your laptop and the buggy to the same wifi network. You can use the IP that we used so the buggy connects automatically to it. But if you want to use another IP, you need to connect a serial cable to the NavQP board, open a shell session in MobaXterm, and run the following command: sudo nmcli device wifi connect . It is good to check your new IP: ifconfig mlan0

   1. Start new session by filling in the wiffi

   2. Ip address: 192.168.1.105

2. Once wifi connection is setup, open an ssh session in MobaXterm, and type your ip/hostname and the username: (you can type b3rb-anne.local instead of the ip)

3. Shell login:

   username: user

   password: user

   4. in a shell prompt run the following ros2 command:

   ros2 launch b3rb_brigup robot.launch.py

   If it does not run well, check history | grep ros

Test drive

Once wifi connection is setup and you can see topics display in foxglove, you are ready to do a test drive.

• First, press the button in the GPS module, you should see that SAFETY is OFF in foxglove

  • Connect the GPS to the CANHUBK3 and press the switch bottom

• Then, choose a mode: manual for manual drive, and auto or cmd_vel for autonomous mode

1. Introduction

2. Hardware setup

Introduction

The RDDRONE-BMS772 is a standalone BMS reference design supporting 3 to 6 cell batteries.

The General Purpose MCU S32K144 provides great flexibility and communication to a PX4 based FMU via UAVCAN or I2C/SMBus. More information about the board can be found in references [1][2].

The BMS will be integrated in the system following the wiring diagram below:

Hardware setup

For setting up the hardware, we need:

• prepare the 3D printed mount

• solder connectors and make cables

• solder the balance leads and make its extension cable

Prepare the 3D printed mount for the RDDRONE-BMS772 board

This particular 3D print will allow the RDDRONE-BMS772 to connect to the pre-production version of MR-B3RB lower chassis metal frame. Future versions may not need this adapter, or may be able to just use standoff's directly.

Solder connectors and make cables

We recommend pluggable cable connectors as shown below. Follow these images for guidance. Some XT60 connectors have a "back shell" to also help cover the solder joints. The backshell is preferable.

Balance leads connection

Because of the limited space on the B3RB. it is preferable to use a balancing leads connector that points upward. This will better clear the PDB that is adjacent to this board, and allow you to more easily plug in the battery's balancing cable later. Solder the white balance connector as shown below:

Balance leads extension cable

You will also need to make an extension cable for the balance leads connector. The leads that typically come as part of the battery is quite short. The suggested cable length is approximately 17cm.

Setup validation - emulating a battery

In this section we will prepare a setup to emulate the battery using a power supply. For this setup we need:

• 4 x 1kΩ resistors

• 2 wires: one black and one red

• Female balance leads connector with wires

Here are the steps:

1. Connect the female balance leads connector with wires and cut them to make them short.

2. Solder the resistors in series then solder two cables in both sides (black and red) as depicted in the picture above. Please make sure that the sides of the black and red wires are similar to the picture.

3. connect Black and red wires of the battery cells emulator to - and + input from the power supply.

Software setup in the BMS

You can compile a binary from this GitHub repository: or flash the existing binary (follow ).

Activate the cyphal can and setup the can id:

Software setup in NavQP

In this section, we present three methods to display received messages via CAN:

• using yakut CLI

• using pycyphal library

• using pycyphal library and ROS2

Prepare environment variables and DSDL namespace

Before the three next steps, you need to prepare the environment variables and add the DSDL namespace as follow:

Using Yakut CLI

Yakút is a simple cross-platform command-line interface (CLI) tool for diagnostics and debugging of Cyphal networks. (For more information refer to [3])

The BMS772 software is already publishing three messages:

• type: reg.udral.physics.electricity.SourceTs_0_1, port: 4096

• type: reg.udral.service.battery.Status_0_2, port: 4097

• type: reg.udral.service.battery.Parameters_0_3, port: 4098

Print published Cyphal message in a terminal:

Using pycyphal library

First, clone the following repository:

Run the script to print the received cyphal messages:

Using pycyphal library and ROS2

Clone the following repository:

Run the ros2 node:

Print the topic:

Once the topic is publishing battery state messages, we can display it in Foxglove. Fist add the topic to the while listed topics in robot.launch.py file

In your PC, download the following layout file and add it to Foxglove studio:

You should see two different tabs: one tab General for displaying the B3RB topics and one tab Battery for displaying the battery status raw data:

References

[1] BMS gitbook:

[2]

[3]

1. What is a ToF camera

2. PMD Flexx camera specification

3. Install Royale SDK

What is a ToF camera

A Time-of-Flight camera (ToF) is a range imaging sensor that produces a depth image, each pixel of which encodes the distance to the corresponding point in the scene [1].

In addition to the camera that produces 2D images, the ToF sensor includes an IR transmitter. By measuring the phase difference between the radiated (red) and reflected (blue) IR waves, we can calculate the distance to the object as depicted in the figure below.

PMD Flexx2 camera specification

The PMD Flexx2 camera intended use are: augmented Reality / Virtual Reality and SLAM. It has the following specifications:

• Depth Measurements from 10 cm to 7 m

• VCSEL with 940 nm Wavelength

• 38,000 3D Pixels with up to 60 FPS

Install Royale SDK

Download the royale SDK from the official website:

You need to fill in the form then you will get an email with a download link available for 24 hours. Use the password that comes with the camera.

You need to download two .zip files: one for your PC where you will display the camera data connected to the PC or the NavQP, and one for the NavQP.

The recent SDK for Flexx2 camera does not have the ROS2 driver. But the previous SDK does. Then, as recommendation, download the zip file libroyale-4.24.0.1201-LINUX-arm-64Bit-ub2004.zip for NavQP.

• Linux PC: libroyale-<ROYALE-SDK-VERSION>-LINUX-x86-64Bit.zip

• Windows PC: libroyale-<ROYALE-SDK-VERSION>-WINDOWS-x86-64Bit.exe.zip

• NavQP: libroyale-4.24.0.1201-LINUX-arm-64Bit-ub2004.zip

Connect the camera to a PC

Connect the camera to the PC using a USB-A to USB-C cable.

Using Linux machine

If you are using a Linux machine, download the zip file libroyale-<ROYALE-SDK-VERSION>-LINUX-x86-64Bit.zip from the download page, add the udev rules then run royaleviewer after reboot:

A GUI will start, click on start button on the bottom right corner to start the display:

You can use the TOOLS button to change some parameters. For example you can change the color range, or the type of data displayed (Gray image, depth image), etc

There is also a LOG button on the top right corner of the GUI where you can find useful debug or error logs.

Using Windows machine

If you are using a windows machine, install the zip file libroyale-<ROYALE-SDK-VERSION>-WINDOWS-x86-64Bit.exe. Unzip the file then run the executable to install the Royale Viewer.

Once installed you can find the executable with the name royaleviewer-royale_<ROYALE-SDK-VERSION> under C:\Users\<USER>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\royale_<ROYALE-SDK-VERSION> (Win64)

Once the program is launched, the steps are similar to those described in Linux sub-section.

Connect the camera to the NavQPlus

Connect the camera to the NavQPlus with an USB-C to USB-C cable (see picture below).

Before using the camera, you need to add the udev rules available in the SDK zip file that you downloaded from PMD download link.

Display via TCP server

Under the bin/ directory, run the binary tcpserver:

Display via RVIZ and ROS2

The Royale SDK provides some sample codes available under samples/cpp/ directory. You should find a directory sampleROS2, which contains code for ROS2 driver.

You need to adjust this code to be able to compile in ROS2 Humble. First create a ROS2 workspace and copy the ROS2 driver there:

Then change the CMakeLists.txt file and the package.xml file to add the package pluginlib dependency:

Then compile the ROS2 workspace using the following command:

Change the path to Royale SDK depending on your environment, and make sure to reference to share/ directory in this command.

Run the ROS2 node:

Make sure that mlan0 interface in listed in the list of interfaces in CycloneDDSConfig.xml file, then run RVIZ in a PC:

References:

[1] Hansard, Miles, Seungkyu Lee, Ouk Choi, and Radu Horaud. Time-of-Flight Cameras: Principles, Methods and Applications. SpringerBriefs in Computer Science. London: Springer London, 2013. .

[2]

[3] SDK download link:

This section explains the essential software required for participating in the NXP Cup 2024 using the MR-B3RB Robot.

Participants will use a combination of pre-configured ROS2 and Zephyr-Cerebri software. Here, "Cerebri" refers to the application layer, while "Zephyr" is the underlying Real-Time Operating System (RTOS). This software stack integrates with the Cognipilot autopilot system, which is available at https://airy.cognipilot.org/.

The following pages provide detailed installation instructions for both the simulation environment and the actual robot. Additionally, there is a section dedicated to explaining the line follower algorithm for the NXP Cup 2024.