Motion control of unconstrained object in mobile robot system

This paper describes a strategy for a pushing operation by wheeled robot. In the conventional approach, the kinematics of the pushing object is mainly focused without considering the dynamical effects such as friction. In this case, it is difficult to cope with environmental variations since the contact point of pushing motion is fixed on the object's surface and the motion of the end effector is limited by friction corn. To address the above issue, the proposed approach makes it possible to achieve not only the control of driving force but also the position control of contact point by using hybrid controller based on disturbance observer. Here the disturbances are compensated by workspace observer so that an acceleration control of the object is realized in workspace. Then the configuration control of the whole system is also easily carried out. Several numerical and experimental results are also shown to confirm the feasibility of the proposed method.