Tip-over stability examination of a compliant anthropomimetic mobile robot

This paper presents a wheeled humanoid robot as a structure composed by upper human-like body and mobile platform. The cart construction is supported by two driving wheels and one caster wheel and subjected to nonholonomic kinematic constraints. The real system configuration of the upper body and its model are represented as a fully anthropomimetic, compliant robot with antagonistic coupled drives. In order to ensure stability of the robot position, the robust control is evaluated. In this paper the focus is not on synthesis of local controllers, but the goal is examination of the limits of the adopted robot control strategy and robot handling with disturbance following from the cart motion (analysis of tip-over stability). In order to avoid tipping over and relying on the Zero Moment Point calculation and control algorithm, the appropriate construction (dimensions) of the cart is adopted. Finally, some simulations are carried out and the influence of different cart movements on the robot balance is analyzed by comparing different cases.