Hoverboard motor + AMT102 incremental encoder

Mihai_Hubalau · February 12, 2022, 5:47pm

Hello,

I spent a couple of hours on the discourse searching for a solution for my problem, but I am yet to find something.

I am trying to configure Odrive for a hoverboard motor, but I want to use an incremental encoder instead of the built-in HAL encoder.
I configured the motor according to the ODrive documentation (from git-hub tag fw-0.4.11), but for the encoder configuration I used:

odrv0.axis0.encoder.config.mode = ENCODER_MODE_INCREMENTAL
odrv0.axis0.encoder.config.cpr = 8192
odrv0.axis0.encoder.config.bandwidth = 1000

The calibration for the motor and the encoder are successful (the motor beeps during the motor calibration, and it spins during the encoder calibration), but when I try to test the velocity loop control, the motor does not spin.

Any suggestion what I did wrong, or what do I have to configure extra?
I would prefer not to update for now to the latest firmware, because my robot control SW relies on the FW 0.4 API.

I have the following setup:

ODrive HW v3.6.56
ODrive FW v0.4.11
10S LiPo (42v) as power supply
2 Ohm break resistor
AMT102 incremental encoder

After configuration I have the following config:
Controller stats:

config:
  control_mode: 2 (uint8)
  pos_gain: 1.0 (float)
  setpoints_in_cpr: False (bool)
  vel_gain: 0.019999999552965164 (float)
  vel_integrator_gain: 0.10000000149011612 (float)
  vel_limit: 1000.0 (float)
  vel_limit_tolerance: 1.2000000476837158 (float)
  vel_ramp_rate: 10000.0 (float)
current_setpoint: 0.0 (float)
error: 0 (uint8)
move_incremental(obj: object_ref, displacement: float, from_goal_point: bool)
move_to_pos(obj: object_ref, pos_setpoint: float)
pos_setpoint: 0.0 (float)
set_current_setpoint(obj: object_ref, current_setpoint: float)
set_pos_setpoint(obj: object_ref, pos_setpoint: float, vel_feed_forward: float, current_feed_forward: float)
set_vel_setpoint(obj: object_ref, vel_setpoint: float, current_feed_forward: float)
start_anticogging_calibration(obj: object_ref)
vel_integrator_current: 0.0 (float)
vel_ramp_enable: False (bool)
vel_ramp_target: 0.0 (float)
vel_setpoint: 120.0 (float)

Motor stats:

DC_calib_phB: -0.7780774235725403 (float)
DC_calib_phC: -0.34574565291404724 (float)
armed_state: 0 (uint8)
config:
  calibration_current: 10.0 (float)
  current_control_bandwidth: 100.0 (float)
  current_lim: 10.0 (float)
  current_lim_tolerance: 1.25 (float)
  direction: -1 (int32)
  inverter_temp_limit_lower: 100.0 (float)
  inverter_temp_limit_upper: 120.0 (float)
  motor_type: 0 (uint8)
  phase_inductance: 0.0004055439494550228 (float)
  phase_resistance: 0.22742202877998352 (float)
  pole_pairs: 15 (int32)
  pre_calibrated: True (bool)
  requested_current_range: 25.0 (float)
  resistance_calib_max_voltage: 4.0 (float)
current_control:
  I_measured_report_filter_k: 1.0 (float)
  Ibus: 0.0 (float)
  Id_measured: 0.0 (float)
  Iq_measured: 0.0 (float)
  Iq_setpoint: 0.0 (float)
  final_v_alpha: 0.0 (float)
  final_v_beta: 0.0 (float)
  i_gain: 22.742204666137695 (float)
  max_allowed_current: 30.375 (float)
  overcurrent_trip_level: 33.75 (float)
  p_gain: 0.04055439680814743 (float)
  v_current_control_integral_d: 0.0 (float)
  v_current_control_integral_q: 0.0 (float)
current_meas_phB: 0.05323946475982666 (float)
current_meas_phC: 0.0025625526905059814 (float)
error: 0 (uint16)
gate_driver:
  drv_fault: 0 (uint16)
get_inverter_temp(obj: object_ref) -> result: float
is_calibrated: True (bool)
phase_current_rev_gain: 0.012500000186264515 (float)
thermal_current_lim: 43.43867492675781 (float)

Encoder stats:

calib_scan_response: 0.0 (float)
config:
  bandwidth: 1000.0 (float)
  calib_range: 0.019999999552965164 (float)
  calib_scan_distance: 50.26548385620117 (float)
  calib_scan_omega: 12.566370964050293 (float)
  cpr: 8192 (int32)
  enable_phase_interpolation: True (bool)
  find_idx_on_lockin_only: False (bool)
  idx_search_unidirectional: False (bool)
  ignore_illegal_hall_state: False (bool)
  mode: 0 (uint8)
  offset: -2328 (int32)
  offset_float: -0.18335938453674316 (float)
  pre_calibrated: False (bool)
  use_index: False (bool)
  zero_count_on_find_idx: True (bool)
count_in_cpr: 0 (int32)
error: 0 (uint8)
hall_state: 0 (uint8)
index_found: False (bool)
interpolation: 0.5 (float)
is_ready: False (bool)
phase: 1.6584234237670898 (float)
pos_cpr: 0.0 (float)
pos_estimate: 0.0 (float)
set_linear_count(obj: object_ref, count: int32)
shadow_count: 0 (int32)
vel_estimate: 0.0 (float)

EDIT

I noticed that the odrv0.axis0.encoder.config.pre_calibrated is always False, even if I specifically set it to True.
From another post I found out that I need to use index for AMT102; so I set:

odrv0.axis0.encoder.config.use_index = True
odrv0.axis0.requested_state = AXIS_STATE_ENCODER_INDEX_SEARCH
# I can notice here the motor moves until the index is found. Also idnex_found = True
odrv0.axis0.requested_state = AXIS_STATE_ENCODER_OFFSET_CALIBRATION
# I can notice that the motor rotates again to perform the calibration
odrv0.axis0.encoder.config.pre_calibrated = True
# After this, the pre_calibrated variable is set to True and is persistent after reset
odrv0.save_configuration()
odrv0.reboot()

But when I try again:

odrv0.axis0.requested_state = AXIS_STATE_ENCODER_INDEX_SEARCH
odrv0.axis0.requested_state = AXIS_STATE_CLOSED_LOOP_CONTROL
odrv0.axis0.controller.vel_setpoint = 10

The motor moves a bit (3 degrees) but then it abruptly stops, and I see that the motor has the error 16 (ERROR_CONTROL_DEADLINE_MISSED)

Motor stats

DC_calib_phB: -0.7711188197135925 (float)
DC_calib_phC: -0.3776278793811798 (float)
armed_state: 0 (uint8)
config:
  calibration_current: 10.0 (float)
  current_control_bandwidth: 100.0 (float)
  current_lim: 10.0 (float)
  current_lim_tolerance: 1.25 (float)
  direction: -1 (int32)
  inverter_temp_limit_lower: 100.0 (float)
  inverter_temp_limit_upper: 120.0 (float)
  motor_type: 0 (uint8)
  phase_inductance: 0.0003835245734080672 (float)
  phase_resistance: 0.2256225347518921 (float)
  pole_pairs: 15 (int32)
  pre_calibrated: True (bool)
  requested_current_range: 25.0 (float)
  resistance_calib_max_voltage: 4.0 (float)
current_control:
  I_measured_report_filter_k: 1.0 (float)
  Ibus: 0.28113868832588196 (float)
  Id_measured: -0.9875475168228149 (float)
  Iq_measured: 3.9099690914154053 (float)
  Iq_setpoint: 6.422600746154785 (float)
  final_v_alpha: 1.7034990787506104 (float)
  final_v_beta: 0.9837055802345276 (float)
  i_gain: 22.562253952026367 (float)
  max_allowed_current: 30.375 (float)
  overcurrent_trip_level: 33.75 (float)
  p_gain: 0.03835245594382286 (float)
  v_current_control_integral_d: 0.11580724269151688 (float)
  v_current_control_integral_q: 1.8720605373382568 (float)
current_meas_phB: -0.014534950256347656 (float)
current_meas_phC: -0.00539824366569519 (float)
error: 16 (uint16)
gate_driver:
  drv_fault: 0 (uint16)
get_inverter_temp(obj: object_ref) -> result: float
is_calibrated: True (bool)
phase_current_rev_gain: 0.012500000186264515 (float)
thermal_current_lim: 44.876373291015625 (float)

Any ideas?

Wetmelon · February 13, 2022, 5:30am

Please send the set of command you used to calibrate and move the motor.

Erase config
Set motor pole pairs
Full calibration sequence
Controller config control mode = velocity
Increase velocity limit
Enter closed loop control
Run motor

Mihai_Hubalau · February 13, 2022, 7:44am

Hello @Wetmelon,

Here are the commands I used for configuration and test:

odrv0.erase_configuration()
odrv0.reboot()
# Motor Configuration
odrv0.axis0.motor.config.pole_pairs = 15
odrv0.axis0.motor.config.resistance_calib_max_voltage = 4
odrv0.axis0.motor.config.requested_current_range = 25
odrv0.axis0.motor.config.current_control_bandwidth = 100
# Encoder configuration
odrv0.axis0.encoder.config.mode = ENCODER_MODE_INCREMENTAL
odrv0.axis0.encoder.config.cpr = 8192
odrv0.axis0.encoder.config.use_index = True
# Controller configuration
odrv0.axis0.controller.config.pos_gain = 1
odrv0.axis0.controller.config.vel_gain = 0.02
odrv0.axis0.controller.config.vel_integrator_gain = 0.1
odrv0.axis0.controller.config.vel_limit = 1000
odrv0.axis0.controller.config.control_mode = CONTROL_MODE_VELOCITY_CONTROL

odrv0.save_configuration()
odrv0.reboot()

# Motor Calibtration
odrv0.axis0.requested_state = AXIS_STATE_MOTOR_CALIBRATION
odrv0.axis0.motor.config.pre_calibrated = True

# Encoder Calibration
odrv0.axis0.requested_state = AXIS_STATE_ENCODER_INDEX_SEARCH
odrv0.axis0.requested_state = AXIS_STATE_ENCODER_OFFSET_CALIBRATION
odrv0.axis0.encoder.config.pre_calibrated = True
odrv0.axis0.config.startup_encoder_index_search = True

odrv0.save_configuration()
odrv0.reboot()

# Test Motor
odrv0.axis0.requested_state = AXIS_STATE_CLOSED_LOOP_CONTROL
odrv0.axis0.controller.vel_setpoint = 10

After I set the vel_setpoint to 10, and read odrv0.axis0.motor.error I get the error code 16

If I dump errors I get the following output:

In [12]: dump_errors(odrv0)
system: not found
axis0
  axis: Error(s):
    UNKNOWN ERROR: 0x00000200
  motor: Error(s):
    MOTOR_ERROR_CONTROL_DEADLINE_MISSED
  sensorless_estimator: no error
  encoder: no error
  controller: Error(s):
    CONTROLLER_ERROR_OVERSPEED

It seems there is also a CONTROLLER_ERROR_OVERSPEED, can this be caused by a misconfiguration of the controller PID?

Wetmelon · February 13, 2022, 4:09pm

Hmm, in the old firmware since you’re still in Counts, you need to increase vel_limit quite a bit. 1000 counts is 1/8 of a turn per second. And a command of 10 is … 1/80? Of a turn per second

Mihai_Hubalau · February 13, 2022, 7:41pm

@Wetmelon, I tried with higher vel_limit values of 10 000 and even 100 000, and I can definitely see a difference; now the motor starts shaking.
I also played a bit with vel_gain and vel_integrator_gain but without success.
I got desperate and updated to the firmware 0.5.4, but with this version the motor turns for about 3-4 seconds and then it stops.
When I switch back to built in HAL sensors, the motor turns smoothly, so it is for sure some misconfiguration related to the encoder.