Closed-loop operation of actuator arrays

An actuator array performs distributed manipulation where an object being transported and manipulated rests on a large number of stationary supporting actuators. The authors have developed a macroscopic actuator array consisting of many motorized wheels. As opposed to a MEMS array, the analysis requires the explicit modeling of the discreteness in the system, including the set of supports, distribution of weight, and generation of traction forces. Using an open-loop wheel velocity field, discreteness causes undesirable behavior such as unstable rotational equilibria, suggesting the use of object feedback. Discrete distributed control algorithms are derived by inverting the dynamics of manipulation. These algorithms reduce the many-input-three-output control problem to a three-input-three-output control problem.