This assumes you are using the 5Ah Turnigy Nano-Tech battery pack.
odrv0.config.dc_bus_overvoltage_trip_level = 12 * 4.2 + 2
odrv0.config.dc_bus_undervoltage_trip_level = 12 * 3.6
odrv0.config.dc_max_positive_current = 150
odrv0.axis0.config.load_encoder = EncoderId.ONBOARD_ENCODER0
odrv0.axis0.config.commutation_encoder = EncoderId.ONBOARD_ENCODER0
odrv0.axis0.config.motor.pole_pairs = 21
odrv0.axis0.config.calibration_lockin.current = 20
odrv0.axis0.config.motor.current_soft_max = 60
odrv0.axis0.controller.config.vel_limit = 20
odrv0.axis0.config.motor.current_control_bandwidth = 2000
odrv0.axis0.config.encoder_bandwidth = 1500
odrv0.axis0.controller.config.spinout_mechanical_power_threshold = -1000
odrv0.axis0.controller.config.spinout_electrical_power_threshold = 1000
odrv0.axis0.config.startup_encoder_offset_calibration = False
odrv0.axis0.config.motor.resistance_calib_max_voltage = 20
odrv0.can.config.baud_rate = 1000000 # should match the baud rate used in hardwarebridge
For the leg motors:
odrv0.config.dc_max_negative_current = -2
odrv0.config.max_regen_current = 2
For the reaction wheels:
odrv0.config.dc_max_negative_current = -25
odrv0.config.max_regen_current = 25
Set the torque constant of each ODrive based on the motor specs. Torque constant can be converted from velocity constant (Kv) as follows:
$ \text{Torque Constant} = \frac{8.27}{\text{Kv}} $
odrv0.axis0.config.motor.torque_constant = 0.32 # for RMDX10
# odrv0.axis0.config.motor.torque_constant = 8.27/90 # for R100kv90
# odrv0.axis0.config.motor.torque_constant = 8.27/110 # for R80kv110
Set the CAN node ID based on the individual joint.
odrv0.axis0.config.can.node_id = 0 # for q0 (left leg motor)
# odrv0.axis0.config.can.node_id = 1 # for q2 (right leg motor)
# odrv0.axis0.config.can.node_id = 2 # for q3 (right reaction wheel)
# odrv0.axis0.config.can.node_id = 3 # for q4 (left reaction wheel)
# odrv0.axis0.config.can.node_id = 4 # for q5 (yaw reaction wheel)
The current_hard_max setting is a safety limit. If the motor surpasses this limit, the ODrive shuts down to protect it from overheating. The appropriate safety limit depends on the motor.
- R100: 120 A
- R80: 60 A
- RMD-X10: 80 A
Note that some of these are higher than the "peak" rated current. That's okay for us as long as the robot is only running for a few seconds at a time.
Also note that ODrive Pro peak current output is 120 A.
odrv0.axis0.config.motor.current_hard_max = 80 # for RMDX10
# odrv0.axis0.config.motor.current_hard_max = 120 # for R100kv90
# odrv0.axis0.config.motor.current_hard_max = 60 # for R80kv110
Don't forget to save after entering these settings.
odrv0.save_configuration()
If using a power supply, use the max voltage of the power supply + 1.
odrv0.config.dc_bus_overvoltage_trip_level = 25
Or if using the batteries, use the number of cells * 4.25 + 2. (Add a little extra in case the battery is filled up).
odrv0.config.dc_bus_overvoltage_trip_level = 53
Use the number of cells * 3.6.
3.3 V is the absolute minimum, but it's better to stop at 3.6 V.
odrv0.config.dc_bus_undervoltage_trip_level = 43.2
Use the C rating on your batteries divided by the number of ODrives being used. This is the current on the power supply side, so it's not necessarily going to match the current demanded by the motors.
With 1.2 Ah pack:
$ \text{Max Positive Current} = 150C * 1.2Ah / 5 = 36 A $
odrv0.config.dc_max_positive_current = 36
With 5 Ah pack:
$ \text{Max Positive Current} = 150C * 5Ah / 5 = 150 A $
odrv0.config.dc_max_positive_current = 150
-1 and 0 if you do not have regen braking.
If you do have regen braking, the highest value would be max charge rate * p count. Max charge rate should be found from the battery specifications, or you can use 1C to be safe...
Remember to divide by the number of ODrives you apply this to. There are 5 ODrives. Currently we require only 3 (the reaction wheels) to have regen.
12S1P, 5C, 1.2Ah:
$ \text{Max Charge} = 5C * 1.2Ah / 3 = 2 A $
odrv0.config.dc_max_negative_current = -2
odrv0.config.max_regen_current = 2
12S1P, 15C, 5Ah:
$ \text{Max Charge} = 15C * 5Ah / 3 = 25 A $
odrv0.config.dc_max_negative_current = -25
odrv0.config.max_regen_current = 25
Set the number of pole pairs.
- RMDX10: 21 (42 poles and 36 slots)
- R100kv90: 21
- R80kv90: 21
odrv0.axis0.config.motor.pole_pairs = 21
Note that resistance_calib_max_voltage can't be more than half your bus voltage.
odrv0.axis0.config.motor.resistance_calib_max_voltage = 20
Once all settings have been saved, run:
odrv0.axis0.requested_state = AXIS_STATE_FULL_CALIBRATION_SEQUENCE
For whatever reason, the reaction wheel actuators tend to calibrate with the wrong encoder direction. You may notice the reaction wheels go off on a runaway feedforward loop in position or velocity control because of this.
For your own sake and the robot's sake, run encoder direction finding right after the calibration sequence.
odrv0.axis0.requested_state = AxisState.ENCODER_DIR_FIND
To test position control:
odrv0.axis0.requested_state = AxisState.CLOSED_LOOP_CONTROL
odrv0.axis0.controller.config.control_mode = CONTROL_MODE_POSITION_CONTROL
odrv0.axis0.controller.input_pos = 1
Note: The latest firmware resets input_pos, input_vel, and input_torque when you change control modes.
Or, for velocity:
odrv0.axis0.requested_state = AxisState.CLOSED_LOOP_CONTROL
odrv0.axis0.controller.config.control_mode = CONTROL_MODE_VELOCITY_CONTROL
odrv0.axis0.controller.input_vel = 1
To disable, change the state to IDLE. This is necessary for saving the configuration.
odrv0.axis0.requested_state = AxisState.IDLE
odrv0.save_configuration()
The watchdog timer may be useful for safety, but may force you to restart during testing.
Starting up in closed loop control mode is probably unnecessary because the CAN bus can set up closed loop control when it's needed.
odrv0.axis0.config.enable_watchdog = True
odrv0.axis0.config.watchdog_timeout = 5 * 60 # 5 minutes
odrv0.axis0.config.startup_closed_loop_control = True
dump_errors(odrv0)
odrv0.clear_errors()
To get shadow count:
odrv0.onboard_encoder0