I have bought and used the LV-168 controller to control 2 motors on a robot/vehicle I have made which so far is just traveling a set distance and stopping. I am using two Tamiya Universal Gearbox kits with two Tamiya Narrow Tire sets. The program simply sets the motor speeds to -255,-255, has a delay for 10 seconds, and then sets motor speeds to 0. One gearbox is at the front of the vehicle, the other is at the rear.
However, upon testing the distance traveled after 10 seconds of running, I am encountering quite a large deviation in the measured distance. The left/right movement is relatively small (gearbox alignment issues) but I am getting up to 15cm deviation in a 360cm trial and 18cm in a 420/500cm trial, and it does not appear to directly follow the discharge of the battery i.e. it is rather random, although over long periods of time the traveled distance generally gets shorter. Is there a reason for the deviation? When I was using a BOEBot controller (with separate power for the microcontroller and motors, and a different Tamiya gearbox (4-speed crank axle)) there was a maximum of 1-2cm deviation on aImost a 700cm run. The old setup however used a relay to control the motors as the BOEBot could not output sufficient current.
I have used 2 0.1uF capacitors on each motor to reduce noise, however, while the motors are running, the controller sometimes does not respond to requests to turn off. I also tried running the motors at speed 200, which still had a large deviation from trial to trial. i.e. (255 speed) 487.7->490.5->497.7 then on 200 speed 341.1, 331.0, 345.1, 338, 338.9
I have since ordered 3 Tamiya 4-speed crank axles, as the metal gearboxes appear to shake a lot on running (but despite that they still go remarkably straight). Does anyone have experience with using Tamiya gearboxes with the LV-168? Is the metal gearbox the least consistent in comparison to the others? A problem I experienced with the 4-speed crank axles was that they tended to exhibit ‘wobble’, which would make the robot travel in a circular/parabolic motion. Also, does decreasing the ‘motorSpeed’ decrease the voltage output to the motors? I would rather run the motors at closer to their 3V spec than at 4.5V with 3 batteries. I am also considering converting the vehicle so only one motor would power it and the other would just be a ‘blank’ axle, but I am having a hard time finding a Tamiya kit for a ‘blank axle’ that keeps the axle in place (restricting left/right movement).