Modeling and Control of a 2-DOF Dielectric Elastomer Diaphragm Actuator

In optical systems, reflectors are commonly used for directing light beams to desired directions. In this paper, a dielectric elastomer (DE) based optical manipulator is developed for two degrees-of-freedom (2-DOF) manipulation. The DE manipulator consists of a diaphragm with four segments that are controlled in two pairs, thus generating 2-DOF tilting motions. Due to its soft and gear-less moving structure, the DE manipulator is lightweight and naturally resistant to mechanical vibrations. Moreover, its nonelectromagnetic-driven mechanism allows it to work under the environments that are exposed to strong magnetic fields. To design a robust control strategy for the actuator, a physics-based and control-oriented nonlinear model is then developed and linearized around the equilibrium point. A feedback control system, which consists of two H-infinity controls, is developed to track two tilting angles along two axes. Experimental results have shown that this manipulator is able to track 0.3° 2-DOF tilting angle with 0.03° accuracy.