Design and analysis of a compliant micro-positioning platform with embedded strain gauges and viscoelastic damper

Abstract

Compliant micro-positioning platforms are necessary for highly precise applications. Measurements of the displacement and reinforcements of the stiffness are two major concerns of any compliant micro-positioning platform. This paper proposes a compliant micro-positioning platform (CMPP) with embedded strain gauges and a viscoelastic damper. The strain gauges, glued at the flexure hinges, measure the displacement of the CMPP and so serve as a displacement sensor. In the open-structured CMPP, the polydimethylsiloxane (PDMS) material which fills the cavity serves as a viscoelastic damper, increasing the stiffness and frequency of the CMPP. PDMS also has the function of harvesting undesired vibrations which affect the performance of the CMPP. The working principle of the developed gauge sensor is established. The effects of the geometric parameters on the strain and the stress distributions are investigated in order to assign the most suitable locations for the strain gauges on the elastic bodies. For purposes of comparison, the performance characteristics in cases without and with an embedded damper are investigated herein. An analytical dynamic model of the CMPP is then established through the Lagrange principle. The geometric parameters of the CMPP are optimized via the differential evolution algorithm. The sensitivity of the developed sensor is determined by the calibrations and the analytical model. It can be concluded that the platform with an embedded strain gauge can determine the displacement as a displacement sensor. The stiffness and the frequency of the platform are reinforced by the viscoelastic damper. The performances can be improved using the differential evolution algorithm. The results indicated that the proposed stage possesses the large range of motion of 860 µm and a high frequency of 345.2 Hz with an infinite fatigue-life of 5.67 × 107 cycles. It is believed that the platform has potential applications in micro-positioning manipulations, in situ microindentation and microscratch testing.