Development of a Mobile Robot Capable of Tilting Heavy Objects and its Safe Placement with Respect to Target Objects

摘要

This paper describes the development of a mobile robot that is capable of tilting of heavy objects. Tilting is a type of non-prehensile manipulation and is important for various forms of object handling, such as the transportation of a heavy object using handcarts or small mobile robots. A critical aspect in the tilting of heavy objects by a mobile robot is preventing the robot from falling due to the large reactive force created when the robot pushes the object. Therefore, first, we developed a mobile robot capable of applying a large force to an object of arbitrary shape without falling, accomplished with passive joints designed not to convey the force other than that applied by the linear actuator of the robot. However, even if the proposed mechanism prevents the robot from falling, other restrictions related to the robot's position and direction of applied force remain, such as slippage between the robot and the object. Therefore, in addition, we derived the optimal position for the robot to tilt a heavy object in an arbitrary direction, even if it caused a positioning error. We derived the constraints from geometric and force conditions, and the distance relationship between the change of the wheels of the motor and the position of the robot to evaluate the robustness against the positioning error. Finally, the position was optimized by maximizing the distance using the brute force search method as an example.