1-DOF Dynamic Pitching Robot that Independently Controls Velocity, Angular Velocity, and Direction of a Ball: Contact Models and Motion Planning

This paper demonstrates that a 1-DOF planar ball-throwing robot has the capability of controlling three kinematic variables of a ball independently: translational velocity, angular velocity, and direction. The throwing motion is modeled using two underactuated contact dynamics, called a finger-link contact model and a fingertip contact model, with a unidirectional transition from one model to another. A combination of a preliminary global search method and a search algorithm based on a simulated annealing (SA) algorithm provides joint torque commands for this highly nonlinear system. An experimental system with a 1-DOF planer manipulator has been developed that throws a disk (ball) in a frictionless plane. The experimental results confirm the validity of the contact models and the feasibility of independent control of the three kinematic variables.