How to setup Ardupilot based Rover with L298N motor driver to control with reverse simple DC brushed motors
A rover with this kind of DC motors:
My rover has two of them: for driving and for steering
An Ardupilot hardware (Pixhack 2.8.4 in my case, fmuv3 is required, AP version should be 4.2+):
L298N motor driver board (MRL298 V2 in my case):
Power module:
Wiring:
| L298N pin | Pixhawk pin/device |
|---|---|
| IN1 | AUX3 |
| IN2 | AUX4 |
| IN3 | AUX5 |
| IN4 | AUX6 |
| GND | any output rail GND |
| ENA | PWM1 |
| ENB | PWM2 |
| motorA | Driving motor |
| motorB | Steering motor |
| Vcc+GND | Power module output |
Ardupilot setup: Assuming calibration and other things are already completed. RC stick mode is set to 1 (right stick controls steering and throttle, left stick is not used).
| Key/Value | Comments |
|---|---|
| BRD_PWM_COUNT,2 | Allocate more AUX pins for relays (reduce amount of PWM pins) |
| BRD_SAFETYENABLE,0 | Don’t require safety switch |
| MOT_PWM_TYPE,3 | Set motor’s type to BrushedWithRelay |
| RELAY_PIN,50 | AUX1 (reserved) |
| RELAY_PIN,51 | AUX2 (reserved) |
| RELAY_PIN3,52 | AUX3 |
| RELAY_PIN4,53 | AUX4 |
| RELAY_PIN5,54 | AUX5 |
| RELAY_PIN6,55 | AUX6 |
| SCR_ENABLE,1 | Enable LUA scripting |
| SERVO1_FUNCTION,26 | Steering |
| SERVO1_MAX,1928 | |
| SERVO1_MIN,1061 | |
| SERVO1_REVERSED,1 | |
| SERVO1_TRIM,1494 | Required for reverse |
| SERVO2_FUNCTION,70 | Throttle |
| SERVO2_MAX,1923 | |
| SERVO2_MIN,1100 | |
| SERVO2_REVERSED,0 | |
| SERVO2_TRIM,1100 | Required for reverse |
| SERVO9_FUNCTION,-1 | AUX1 GPIO mode (reserved) |
| SERVO10_FUNCTION,-1 | AUX2 (reserved) |
| SERVO11_FUNCTION,-1 | AUX3 |
| SERVO12_FUNCTION,-1 | AUX4 |
| SERVO13_FUNCTION,-1 | AUX5 |
| SERVO14_FUNCTION,-1 | AUX6 |
BrushedWithRelay motor mode reserves the first relays (AUX1 and AUX2 in our case), so we must use other relay outputs for our purposes. In this case AUX3-AUX6 outputs will be used.
In Mission Planner upload the set_rotation_dir.lua script to the scripts folder and reboot the Pixhawk.
