Intersample Discretization of Control Inputs for Flexible Systems With Quantized Cellular Actuation

Piezoelectrically driven cellular actuators are a technology inspired by biological muscles. Like muscle tissue, several serial and parallel combinations act in concert to achieve the desired motion. In order to simplify the drive electronics and mitigate the effect of hysteresis in piezoelectric materials, it is desired to restrict each input to simple on-off commands. This quantizes the actuation greatly. The cellular actuators also have a number of lightly damped flexible modes, which may be higher than the Nyquist frequency of the discrete–time controller. These may still cause long settling times. We propose a method to convert a continuously variable control input from a controller whose design does not consider quantization and flexible effects to a quantized signal that can be implemented by the actuator which also reduces oscillation in known lightly damped modes.