Integrated Structure/Control Design Using Finite Element Models-Preliminary Results

A new methodology for the integrated structure and control design is developed and applied to flexible robot arms. To maximise performance from an electromechanical system, the structure design and controller design should be performed concurrently. The final design of structure is thus better suited for control. The finite element method is used to model the system for dynamic analysis. Various system characteristics including poles and seros are described as functions of design variables, which are geometric parameters describing the finite element model of the structure. The relationship between the design variables and the system characteristics are linearised by using the generalized jacobian. The inverse problem, that is to find design variables that provide specified system characteristics, is then solved by using the pseudo-inverse of the jacobian. The example of a single link flexible structure is considered and the structure is optimised with respect to the first natural frequency. The moment of inertia about the actuator axis is reduced and the end-point deflection is kept within a given bound. Some of the critical issues of the design process are highlighted.