KARP runs its wheel motors through ODrive hardware connected to an AMD/Xilinx Kria KV260 running PetaLinux and ROS 2. The reproducible path is: wire the RBE-102024-003 hub motors and AEDR-8300 encoders to a two-axis ODrive, isolate the USB link, install the Python ODrive tools, calibrate with the project’s configuration script, then expose wheel velocity through odrive_ros2_control. The original project used an ODrive firmware 0.5.1 branch, so firmware, board generation, Python package and ROS 2 code must be matched rather than mixed casually.
How KARP’s motor-control stack is arranged
The KV260 is the high-level computer. PetaLinux hosts Python, ROS 2 and the ODrive hardware interface. ODrive closes the fast motor-control loops locally; ROS 2 sends wheel commands and reads state through odrive_ros2_control. This separation keeps the motor’s position, velocity and current regulation on the controller while the robot software handles differential-drive behavior.
KARP uses a two-axis ODrive board for its left and right traction motors. The project’s software packages are organized as odrive_ros2_control, odrive_bringup, odrive_description and odrive_hardware_interface.
Motor and encoder used by KARP
| Component | Specification | Role in KARP |
|---|---|---|
| Wheel-hub motor | RBE-102024-003, three-phase, 24 V nominal, 20–36 V operating range, 5 N·m rated load, CW/CCW operation | Traction motor |
| Encoder | AEDR-8300 optical incremental encoder, 3200 counts per revolution (CPR) | Position feedback |
| Hall sensor | Present on the motor, but not selected for KARP’s position feedback | Not used by the project’s encoder configuration |
The configuration script sets the encoder CPR to 3200 and uses a motor torque-constant value of 8.27/16. Treat those values as part of this motor-and-encoder pairing; changing the sensor or motor requires a corresponding configuration review.
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#1 Best Overall
- Hardware Version:ODESC V4.2
- Drive motor:Brushless DC motor (BLDC)
- Braking method:Power resistors, battery recycling
- Working voltage:8-24V, 8-56V
- Maximum current:120A Continuous current:70A
Wiring the RBE motor, encoder and ODrive
Connect each motor and its encoder to one ODrive axis. The board’s phase labels and encoder labels are the electrical reference; do not infer connections from wire color for the motor phases.
| Device lead | ODrive connection |
|---|---|
| Motor phase U | ODrive A |
| Motor phase V | ODrive B |
| Motor phase W | ODrive C |
| Encoder red (+) | 5 V |
| Encoder black (−) | GND |
| Encoder white (A) | Encoder A |
| Encoder grey (B) | Encoder B |
| ODrive power | 24 V supply |
Use the optical AEDR-8300 channels for feedback as the project does, not the motor’s Hall output. Verify polarity, connector pinout and power isolation with the board unpowered before applying 24 V.
Why the USB isolator is part of the design
KARP places an ADuM3160 USB isolator between the KV260 host and ODrive to prevent a ground loop when USB and the ODrive’s DC supply are connected simultaneously. ODrive’s current getting-started guidance gives the same requirement: USB and DC power may only be used together with a USB isolator on each ODrive. Without isolation, the USB shield or ground can create an unintended current path between the host and motor power system.
Rank #2
- ODESC V4.2 single driver board, STM32F405RGT6 Microprocessor
- Working voltage:DC 8V-56V, Continuous current: 70A, Peak current: 120A.
- Braking methods: Power resistors & battery recycling
- Drive motor: Brushless DC motor (BLDC)
- Control modes: speed mode, position mode, current mode, torque mode for trajectory planning.
Prepare PetaLinux and verify the ODrive
- Install the Python package. In the PetaLinux environment, run
sudo pip3 install --upgrade odrive. - Check USB discovery. Start
odrivetooland confirm that the controller is detected before attempting calibration. - Confirm the electrical setup. Make sure the isolator is between the KV260 and ODrive, the ODrive has its motor supply, and the encoder is connected to the intended axis.
- Freeze a compatible software set. Record the ODrive board model, firmware revision, Python package version, ROS 2 branch and PetaLinux image. The original KARP project used an
odrive_ros2_controlbranch for ODrive firmwarev0.5.1; it reported that newer firmware did not work correctly in that setup.
That firmware note is historical, not a guarantee for every ODrive board. Check the branch’s assumptions and the controller’s reported firmware before deploying.
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Run the project’s odrive_config.py script only after the board is detected and the mechanics can move safely. The script configures both axes, selects the motor and encoder modes, applies current and PID parameters, performs calibration and moves the motor through test positions.
- Secure the robot so an unexpected wheel movement cannot cause injury or damage.
- Start
odrivetooland verify the intended ODrive is visible. - Run
odrive_config.pyfrom the project workspace. - Watch the calibration and test-position movements. Stop if an axis rotates in the wrong direction, stalls, or produces an encoder error.
- Save the resulting configuration and record the exact script revision alongside the firmware version.
Calibration is not a substitute for checking phase order, encoder A/B wiring or current limits. A successful command sequence with incorrect wiring can still produce unsafe motion.
Rank #3
- Hardware Version:ODESC V4.2
- Working voltage:8-24V, 8-56V
- Drive motor:Brushless DC motor (BLDC)
- Maximum current:120A Continuous current:70A
- Microprocessor:STM32F405RGT6
Build and launch the ROS 2 interface
The tutorial builds its ROS 2 workspace directly on the KV260 with colcon build after installing the ROS 2 development packages and colcon extensions listed by the project. Compiling on the target is expedient for a prototype; an external, repeatable build is preferable for production images.
- Install the project’s specified ROS 2 development dependencies and colcon extensions in the PetaLinux image.
- Source the ROS 2 environment and build the workspace with
colcon build. - Source the resulting workspace.
- Launch the hardware stack with
ros2 launch odrive_bringup odrive.launch.py.
Command and state interfaces
KARP exposes left- and right-wheel velocity command interfaces through a differential-drive controller. A velocity command can be published to /joint0_velocity_controller/commands. The /dynamic_joint_states topic reports joint position, speed, torque, temperature and error information. Confirm the actual joint names and controller activation in the launch configuration before integrating a higher-level navigation node.
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ODrive documents its motor controller as a cascaded position, velocity and current control loop. Each stage is PID-style, and limits are applied between stages.
Rank #4
- 【Precise PWM Control】This motor speed controller uses PWM technology for smooth 0 to 100 speed adjustment. The digital display shows speed percentage clearly for accurate motor control.
- 【High Power Range】PWM motor controller supports 10V to 55V input and 40A continuous current. Suitable for electric motor speed regulation in CNC equipment robotics and industrial control setups.
- 【Forward Reverse Switching】Built with a forward reverse switch for convenient motor direction control without complex rewiring. Helps simplify operation during equipment adjustment and daily use.
- 【Compact Functional Design】Features a control knob screw terminal wiring and protective housing for heat dissipation. Product size is 4.33 x 3.07 x 1.49 inches for easy installation.
- 【Wide Application Use】This motor governor fits various motor regulation tasks in automation benches workshop tools robotics projects and CNC machine systems where adjustable speed control is needed.
Position mode
Position mode runs the complete cascade: a position target is converted through the position and velocity stages into current demand.
Velocity mode
Velocity mode feeds the velocity stage directly. This is the natural interface for KARP’s wheel-speed commands because ROS 2’s differential-drive controller produces wheel velocities rather than absolute wheel positions.
Torque mode
Torque mode uses the current controller directly. It is useful when the application, rather than ODrive’s outer loops, must determine torque demand.
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- 【Motor controller parameters】three-phase DC brushless motor control board power 400W, wide voltage 6-60V, DC three-phase brushless Hall controller supports PLC, 0-5V touch volume control, supports PWM control, amplitude 2.5-5 V, this driver is only suitable for DC brushless Hall motor 120 degrees angle
- 【DC motor governor】MA MB MC phase line output motor. 5V GND main board comes with 5V power supply. VCC GND main power supply. SC speed pulse signal output. DIR direction control forward/backward control interface. STOP stop control interface. BRAKE brake control indication brake control port. Speed control input speed control signal.
- 【Motor governor】Brushless motors generally also have five Hall wires or interfaces. Two of them are Hall power cables and three are Hall signal wires to distinguish the Hall power cord in particular. The three Hall signal wires are generally marked with a b c, and the driver board also has three ports of ha Hb Hc and other similar characters, which are connected accordingly, and have overcurrent, forward/reverse/stop/brake functions
- 【Note】Since there is no fuse in the power supply circuit of the main board, it needs to be added by yourself. Otherwise, human error will cause product damage. The wiring tester will conduct a low current and low voltage test first, and then a high current and high voltage test after success. For bare board modules, pay attention to the insulation of the wires when wiring, and do not let strong voltages contact the board.
- 【Wide application and service】The application scenarios of brushless motors are very wide, such as electric vehicles, drones, fans, blowers, smoke machines, etc. If you encounter any problems, please contact us, we are online 24 hours a day, we will give you a perfect solution!
A practical tuning order
- Stabilize the velocity loop first.
- Adjust position gain only when position control is required, reducing overshoot rather than masking it with excessive current limits.
- Set the integrator in relation to the loop bandwidth so steady-state error is corrected without causing windup or oscillation.
Use the reported speed, torque, temperature and error fields while tuning. Change one group of gains at a time and test with the wheel unloaded before applying traction load.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Firmware and ODrive product boundaries
The public ODrive repository describes v3.x firmware as no longer under active development (NRND). Current Pro, S1 and Micro firmware is maintained but not publicly available, while separate legacy documentation covers v3.6. The current documentation and the historical KARP tutorial therefore do not describe one interchangeable software target.
| ODrive family in current documentation | Published bus-voltage limit | Brake-resistor note |
|---|---|---|
| Pro | 58 V | Pro does not include a built-in brake-resistor feature; regenerative braking generally needs a Regen Clamp or battery. |
| S1 | 50 V | Use the current product documentation for the supported regeneration arrangement. |
| Micro | 30 V | Micro does not include a built-in brake-resistor feature; regenerative braking generally needs a Regen Clamp or battery. |
The current guide lists a brushless motor, encoder unless operating sensorless, and a power supply or battery above 12 V as prerequisites. Those limits are product-family specifications, not permission to connect a KARP motor without checking the exact board’s electrical ratings.
Handling regenerative braking
When a driven wheel decelerates, energy can return to the DC bus. For Pro and Micro, the current ODrive guidance says there is no built-in brake-resistor feature; a Regen Clamp or a battery is generally required to absorb that energy. Design the bus-voltage protection before testing aggressive deceleration, downhill motion or a heavy robot load.
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Failure modes to check first
- ODrive is not detected: check the USB isolator, cable, PetaLinux USB support and ODrive power before changing ROS 2 code.
- Encoder errors or implausible position: recheck 5 V, GND, A and B conductors and confirm the 3200 CPR setting.
- Motor runs backward: stop the test, verify phase and encoder assignment, then apply the project’s direction settings rather than compensating blindly in ROS 2.
- Calibration stalls: inspect mechanical binding, current limits, phase connections and encoder feedback.
- Launch succeeds but no wheel moves: verify that the controller is active, the command topic and joint names match the launch configuration, and the ODrive firmware matches the ROS 2 branch.
- Bus voltage rises during braking: stop high-energy tests and add the appropriate regeneration-energy path for the exact ODrive hardware.
Reproduction checklist
- Kria KV260 running the intended PetaLinux image.
- Two RBE-102024-003 motors with AEDR-8300, 3200 CPR optical encoders.
- Two-axis ODrive with correctly mapped U/V/W and encoder wiring.
- 24 V motor supply and an ADuM3160-class USB isolator between host and controller.
- Matching ODrive firmware, Python package and
odrive_ros2_controlbranch. - Successful
odrive_config.pycalibration before ROS 2 launch. - Validated differential-drive velocity commands and monitored joint-state errors.
The dependable implementation is therefore a matched hardware-and-software stack, not simply an ODrive connected to a Linux board: KARP’s motor data, encoder CPR, isolation arrangement, calibration parameters and firmware branch all form one configuration.
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