Control of Wheeled Mobile Manipulators with Flexible Suspension Considering Wheels Slip Effects

Wheeled mobile manipulators utilize both the locomotion capabilities of the wheeled platform and manipulation capacity of the arm. While the modelling and control of such systems have previously been studied, most of them have considered robots with rigid suspension and their wheels are subject to pure rolling conditions. To relax the aforementioned limiting assumptions, this research addresses modelling and control of a mobile manipulator with flexible suspension while considers the frictional effects. To this end, the Newton-Euler approach is employed and the modelling process is elaborated. To control the system, a two degree-of-freedom policy is suggested at two levels. In the first level, the Multiple Impedance Control (MIC) algorithm is modified and then is effectively utilized. Next, in the second level, the wheels actuating torques are adjusted such that the required forces/torques of the platform resulted from the first level be realized. The obtained simulation results support the proficiency of the suggested control scenario to control of wheeled mobile robots with flexible suspension and pneumatic tires.