LIGHT-DRIVEN ACTUATOR WITH SHAPE MEMORY ALLOY FOR MANIPULATION OF MACROSCOPIC OBJECTS

With the aim of manipulating macroscopic objects, the possibility of improving energy conversion efficiency of light-driven actuators (LDAs) was investigated. Thermal expansion is one of the most efficient mechanisms reported so far but a rough estimation revealed that its upper limit in efficiency is similar to 10(-4)%. Thermodynamics suggests several percent can be achieved in theory, so by using a suitable mechanism there is room for improvement. Based on those considerations we propose a LDA using a pre-tensioned wire of shape memory alloy. This design reduces the energy loss in converting the input light into mechanical motion. We demonstrated that a force larger than 1 Newton and an energy conversion efficiency of 1 percent can be achieved.