Steering motor issue
Steering motor issue
Upon test of the initial driver for PWM control from the Raspberry Pi, weird behaviour of the steering motors was seen. Manual test of the control signal using an Analog Discovery yieled similar behaviour.
The weird behaviour can be described as:
- Sporadic sluggish movement of the front wheels to their end position
- Inability of the steering motors to drive the front wheels to their end position with the robot at a standstill on a flat wooden surface.
Upon inspection of the difference from the DRobotti V.1 and V.2 steering motors, it is noted that:
- V.1 uses Servox SW0231MG motors, producing a max torque of 15 kg/cm, https://www.servocity.com/sw0231mg-waterproof-standard-digital-servo/
- V.2 uses Hitec HS-422 motors, producing a max torque of 4.1 kg/cm, https://www.servocity.com/hs-422-servo/
The motors are currently driven at 5V, which results in them not being able to produce their maximum rated torque. However, recorded (attached) worst case captures the current V.2 motors being stuck in an undesired position, potentially driving the DRobotti in an undefined direction.