Abstract
Above their glass transition temperatures (T_g), shape-memory polymers (SIVIPs) can be deformed by applying a small load. They maintain their shape after they have been cooled below Tg, and then return to a predefmed shape when next heated above T_g. The reversible change in the elastic modulus between the glassy and rubbery states of SMPs can be of the order of 100 to 1000 times. Exploiting these characteristics, this study seeks to evaluate the application of SMPs to low energy position keeping of a robot ann. Prototypes of a SMP-based position keeping module were fabricated, together with a prototype hybrid McKibben actuator using a SMP. When the SMP is heated above T_g it softens and the prototypes can deform upon the application of a small load. After the robot aim attains a desired length, the SMP is cooled to below T_g and it is fixed in a rigid state. This state is maintained without the need for any electric power, air supply or control system. The enhanced versatility of this application of SMP to position keeping of a robot is shown through a series of experiments conducted on the prototypes.
