Stick-slip operation of the modular distributed manipulator system

The modular distributed manipulator system (MDMS) is a novel materials handling system which is a fixed array of actuated wheels capable of inducing arbitrary motions in the plane. The wheels transport and manipulate objects that rest on the array. The motion of the object is determined by a combination of object weight distribution, actuator dynamics, speed control law, and friction between the wheels and the manipulated object. This work focuses on a stick-slip friction model and its impact on the dynamics of an object on the array. Factors such as coefficient of friction and object size and weight determine which wheels roll and which wheels slide relative to the object. The paper determines the ranges of parameters for which all wheels are in either sliding contact or rolling contact. Simulations are performed to demonstrate the dynamics of the system.