An improved design of Piezo-Composite Actuator used as the artificial muscle for bio-inspired robots

During the past decade, lots of diverse researches have been conducted on application of smart materials to build small-scale robots. Several small, powerful, and reliable piezoelectric actuators using piezoelectric ceramic materials have been invented. Among them, LIPCA was introduced as the best unimorph actuator suitable for bio-inspired robots. The actuator plays the role as an artificial muscle which can produce up-and-down bending motion as voltage is applied. This paper presents an improved design of LIPCA (lightweight piezo-composite actuator) by using the direct piezoelectric effect along the poling direction (d₃₃ mode) with interdigitated electrodes patterned on the two surfaces of PZT wafer that could help the new LIPCA enhancing the actuation performance considerably. An analytical model is used to give a comparison on the performance between the new design and the traditional LIPCA. Numerical optimization analysis on the design variables as electrode width, gap between electrodes and applied voltage for poling process is also performed.