Sensing capability of a PZT-driven cantilever actuator

An electromechanical transducer can exert a mechanical force to the tested structure because of the electromechanical interaction when ac power is applied. Once this interaction is characterized, the output mechanical variables can be indirectly evaluated by measuring the input electrical variables, which indicates that the transducer performs as a sensing cum actuating (SCA) device. In this paper, a PZT-driven cantilever actuator is identified either analytically or numerically. The four transduction functions in the matrix are determined by imposing two different boundary conditions. It is more difficult to get the two transduction functions defined under the boundary condition in which the velocity at mechanical output port is zero. A method for overcoming these experimental difficulties is to attach weights of different known mass to the output port of PZT-driven cantilever actuator to generate information for constructing the matrix. Simulation shows that the proposed methods fulfill the purpose and significantly improve the convenience of using the sensor-less technique for measuring mechanical impedance.