Implementation of Torque Controller for Brushless Motors on the Omni-directional Wheeled Mobile Robot
This addresses the need for more robust control in wheeled mobile robots for competition settings, though it is incremental as it builds on existing PI control methods.
The researchers tackled the problem of low-level controller gain tuning for wheeled mobile robots in competitions, where floor surface changes affect performance, by implementing a torque controller that combines a PI controller with motor dynamics. The results showed that the torque controller provided better robot paths compared to a regular PI controller across experiments with three different carpets.
The major issue for the wheeled mobile robot is the low level controller gains tuning up especially in the robot competition. The floor surface can be damaged by the robot wheels during the competition, therefore the surface coefficient can be changed over time. PI gains have to be tuned before every match along the competition. In this research, the torque controller is defined and implemented in order to solve this problem. Torque controller consists of a PI controller for the robot wheel's angular velocity and a dynamic equation of brushless motor. The motor dynamics can be derived from the energy conservation law. Three different carpets, which have the different friction coefficients, are used in the experiments. The robot wheel's angular velocity profiles are generated from the robot kinematics with different initial conditions. The output paths of the robot with the torque controller are compared with the output paths of the robot with regular PI controller when the same wheel angular velocity profiles are applied. The results show that the torque controller can provide a better robot path than the normal PI controller.