Verifing Robot Movement at Low Speed

Austin Schwartz

The Rover Zero and Rover Pro use brushless DC motors installed in the front of the robot. These then power wheels which connect via a track to the back wheels to achieve 4WD, when using the 4WD kit.

Sometimes the rubber track is tight when the robot first arrives and the robot will have trouble moving at very low speeds, particularly when turning. The belts will loosen a bit as the robot drives more.

At Rover production we use this code to verify the movement of the robot at low speeds.

rostopic pub /managed/joy geometry_msgs/Twist "{linear: {x: 0.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}" -r 10 

While there is some variation depending on the friction of the surface the robot is driving on, we typically see the Rover able to turn at +/-0.3 rad/s in closed loop configuration and +/-0.9 rad/s in open loop configuration (editing the angular Z).

If it takes significantly more than either of those speeds to turn the robot, first try a different surface for the robot to drive on and test again. If there is still trouble, contact us here.