Design, manufacture, and application to space robotics of distributed piezoelectric film sensors

Abstract

This paper describes the development and manufacture of distributed piezoelectric film strain sensors. The sensors are spatially shaped such that, when bonded to a vibrating structure, their output is selectively proportional to a particular deformation pattern of the flexible structure. In this paper, the selectivity is based on the spatial orthogonality of the structure's natural modes of vibration, but orthogonality of arbitrary basis functions might also be exploited. The generalized amplitudes of these basis functions are states in a multiple-flexible-body dynamic simulation; the new sensors permit direct measurement of states otherwise available only from a dynamic estimation procedure. An experimental two-link planar manipulator is employed in this study to quantify the performance of these sensors in a dynamic environment. Sensor outputs are compared with the state estimates generated by open-loop simulation and by several Kalman filters. Surprisingly close agreement is found, even for a crude linear estimator. This process can also be viewed as using the piezoelectric film sensors to evaluate state estimation procedures applicable to multiple-flex ible-body systems.