Problems with SPI Management

1

Hello friends!

  1. I use ODrive v3.5-48V
  2. Encoders: AS5047P-TS_EK_AB connected by SPI.
  3. Firmware: - https://github.com/TobinHall/ODrive/tree/Non-Blocking_Absolute_SPI

Set the settings:
odrv0.axis0.encoder.config.abs_spi_cs_gpio_pin = 4
odrv0.axis0.encoder.config.mode = 257
odrv0.axis0.encoder.config.cpr = 2**14

Encoders:

error = 0x0000 (int)
is_ready = True (bool)
index_found = False (bool)
shadow_count = 20872 (int)
count_in_cpr = 4487 (int)
interpolation = 1.0 (float)
phase = 1.8239965438842773 (float)
pos_estimate = 20872.3125 (float)
pos_cpr = 4489.6875 (float)
hall_state = 7 (int)
vel_estimate = -625.0 (float)
pos_abs = 4487 (int)
config:
  mode = 257 (int)
  use_index = False (bool)
  abs_spi_cs_gpio_pin = 4 (int)
  pre_calibrated = False (bool)
  idx_search_speed = 10.0 (float)
  zero_count_on_find_idx = True (bool)
  cpr = 16384 (int)
  offset = 11282 (int)
  offset_float = 0.7106562852859497 (float)
  bandwidth = 1000.0 (float)
  calib_range = 0.019999999552965164 (float)
  ignore_illegal_hall_state = False (bool)

When turned on, the motor vibrates violently and jitter .
I use - move_to_pos and my engine shuts off with errors.

In [85]: hex(odrv0.axis0.motor.error)                                           
Out[85]: '0x10'

In [86]: hex(odrv0.axis0.controller.error)                                      
Out[86]: '0x1'

In [87]: hex(odrv0.axis0.error)                                                 
Out[87]: '0x200'

If disconnect <axis>.controller.config.vel_limit_tolerance = 0
Everything is working. But the vibration remains.

For some time the function even works move_to_pos.
But then everything turns off and an error pops up on the sensor.

In [94]: dump_errors(odrv0)                                                     
axis0
  axis: Error(s):
    ERROR_ENCODER_FAILED
  motor: no error
  encoder: Error(s):
  controller: no error
axis1
  axis: no error
  motor: no error
  encoder: no error
  controller: no error

In [93]: hex(odrv0.axis0.encoder.error)                                         
Out[93]: '0x80'
2

Help please. Can eat the ideas?
Can drive vibrations due to ADC rattle?

Figure_1
Figure_1.png1853×989 73.4 KB

Maybe there are those who used SPI?

3

Have you tried tuning your gains?

4

Tried, it’s unreal. An error: 0x80
Tell me, is this normal?

Screenshot%20from%202019-08-07%2016-51-26
Screenshot from 2019-08-07 16-51-26.png1920×1080 89.7 KB

I use: start_liveplotter(lambda:[odrv0.axis0.encoder.pos_estimate, odrv0.axis0.controller.pos_setpoint])

5

Oh, wow. I thought you meant the jittering, sorry. Yes, that is very strange behaviour. I have no idea what would cause that.

The sensor is sending the absolute position right? Such a big jump, looks like something is wrong with the signal, or the sensor is picking up noise.

From what I see in the specs you should have 0.063 degrees of noise = \frac{0.063}{(\frac{360}{2^{14}})} = 3 steps, so the jittering seems normal. But that jump of 200 steps is really weird.

See if you can electrically isolate your sensor. Using a plastic spacer or axle or something. To see if the noise goes away. In my case I changed my motor mounts to plastic, after that my other sensors picked up a lot less noise.

6

i think
odrv0.axis0.encoder.config.cpr must be 4000