Model-Based Control of an Advanced Actuated Part-Fixture System

In this paper the dynamical behavior of a part and an actuated fixture system is studied. The part is modeled using the finite element method. Subsequently, a reduced model is established using the Craig-Bampton reduction method in order to create a small-sized model, accurately describing the dynamic behavior of the part. The clampers and locators of the fixture are modeled as springs. The fixture frame is considered to be much stiffer than the locators such that it provides zero displacement boundary conditions to the locators. An electromechanical actuator is utilized to provide the adaptive clamping forces. After investigating proportional control, integral control, the three term classical PID controller and a lag filter for dynamic compensation, the analysis shows that position feedback can be used effectively in combination with integral control action to minimize unnecessary displacement of the workpiece and increase the bandwidth of the actuated fixture system.