No motor output with skid steering


I’m making a rover with a navi2 board. Previously used the board on a quad.
The pre-built image contains Rover 4.0.0.

When configuring the rover with skid steering:
SERVO1_FUNCTION = 73 (Throttle Left)
SERVO3_FUNCTION = 74 (Throttle Right)

PWM_MOT_TYPE = 3 (Brushed with relay)

there is no response on the motor pwm outputs or on the relay pins. Neither using manual control or using motor test. Checked outputs both in MP and with scope on power rail. Other outputs (RC pass through etc) seems to work.

Not sure if its a bug or I have missed some parameters? Any advice or history with skid steering and brushed motors?
Attached is the parameter file.rover_parameters.param (15.2 KB)

Which motor controller are you using?

I’m using a standard H-bridge (L9110). Not sure it will actually work with regards to voltage leves and such. But regardless of motor controller type the pwm pin should generate output signals, which it does not.

Servo rail is powered by a 5V BEC. Measured and everyhing looks good.

Try to set “mot_pwm_type” to “normal” and see if the outputs generate a signal. There are a few threads here and in the Emlid forum of people trying to use “brushed with relay” without success with Navio2.
I asked about the motor controller to see if you really need to use “brushed with relay”. Your options are:

  1. Use a microcontroller between the Navio2 and the motor controller to read the PWM signal and output a PWM signal + on/off.
  2. Use a different motor controller
  3. Use a different flightcontroller

MOT_PWM_TYPE = Normal works fine.

So after reading up on the problem on the Emlid forum, I guess I have to add an arduino in between the servo rail and H-bridge as you suggest.

I still think its strange I don’t get any signal out of the pwm, even if its just 400Hz.

Thanks for the answers, I will give it a try. Might come back with additional questions tough. The navio creates problems every time you try somthing new :smiley: Should have just sticked with a pixhawk.