Abstract: A smart cantilever structure based on Galfenol alloy is developed, and a dynamic distributed parameter model is built, which takes into account the influence of adhesive layer on the dynamic performance of structure. The proposed model, excited with magnetic coil, can be used to predict the dynamic behavior of the smart cantilever structure. In order to reduce the eddy current loss from high frequency magnetic field, a laminated U- shaped frame is adopted for the flux return path in the solenoid driven magnetic circuit. Since the state output variable of the distributed parameter model is not directly coupled with the reference voltage, a decoupling control method of sliding mode variable structure based on the distributed parameter model is proposed. Then direct coupling of input and output can be realized through decoupling of output variable matrix. Furthermore, in view of the subharmonic disturbance in the flexible structure, Lyapunov function is adopted to prove the stability condition of the control system under mismatch condition, and the conclusion is verified via computer simulation. Moreover, proportional-integral control is employed for comparison with the proposed control. It can be seen from the experimental tests that the proposed control method can not only solve the decoupling problem in the distributed parameter model, but also efficiently suppress the nonlinear hysteresis of Galfenol alloy, thus enabling the system to better track the external reference input.

Key words: Adhesive layer, Cantilever beam, Dynamic tracking control, Galfenol alloy, Sliding mode variable structure