When the tracked mobile robot moves outside, especially on the soil, it's hard to control the robot precisely. Even if you got extremely accurate odometry feedback, estimating your pose is still very hard. One of the major issues of this problem is the slip between the track and the soil. It causes the kinematic model to be incorrect. This repository assumes an unknown slip exists in the kinematic model and uses adaptive control to find the slip while tracking the predefined trajectory adaptively.
This system is built in Simulink 2020b.
Since we need to control a motor, it's improtant to get the transfer function of the motor from system identification. After the System ID experiment, we get the motor transfer function:
We design a PI control to control the motor.
Trajectory tracking adaptive control scheme.
tracking error: Red line is the result with the adaptive law. Blue line is the result without the adaptive law.
desired motion command tracking error: Red line is the result with the adaptive law. Green line is the result without the adaptive law. Blue line is the reference.
slip adaptive tuning performance
With the adaptive law, the tracking error improves tremendously, and the motion command also converges to the desired command.
M. Cui, ‘‘Observer-based adaptive tracking control of wheeled mobile robots with unknown slipping parameters,’’ IEEE Access, vol. 7, pp. 169646–169655, 2019.