Force Control for Vehicle Robot With Inverted Two-wheeled and Stable Travelling Modes

Abstract

This research proposes a force control for a vehicle robot with an inverted two-wheeled/stable traveling mode. The conventional inverted two-wheeled vehicles have advantages such as the capability of pivot turn compared to the vehicle robots with three or four wheels. Additionally, if an arm (manipulator) is mounted on the vehicle, multi-functionalization of the mobile robot is expected. However, the inverted two-wheeled vehicles have disadvantages such as statical instability and deterioration of the main tasks and inverted-pendulum control due to mutual interference because of the presence of the underactuated joint. Therefore, this research proposes a force control as one of the multi-functionalization by a mobile robot with the advantages of both two-wheeled and stable traveling mode. This research introduces a variable compliance control for the pitch angle direction, which enables the flexible and stable transition between a two-wheel mode and stable traveling mode. The proposed method realizes a stable contact motion to the environment with achieving a soft landing and stable inverted traveling movements at the transition from the two-wheel mode to three-wheel mode. The simulations evaluate the proposed method.