Improving Position Control and Energy Consumption of a Two Degrees of Freedom Robotic Module Actuated by Shape Memory Alloy Springs

Modular robots consist of a few modules that assemble together to create different combinations in order to adapt to new circumstances, perform new tasks or recover from damage. These characteristics allow modular robots to explore unstructured and hazardous environments. It would be greatly beneficial to have manipulators which are scalable to a small size, flexible yet strong and complete the assigned tasks with dexterity. Shape memory alloys (SMA) are a kind of smart materials with attractive features as high power to weight ratio in addition to simple and silent actuation. Using SMA as the actuator of modular robots leads to more miniaturization of such devices. Further, using controllable modules will provide more capable modular systems. In this paper, a fuzzy control design is developed for position control of a two degrees of freedom (DOFs) module incorporating SMA springs as the actuators. The actuators produce relative motion between two parallel plates which linked together by a special ball and socket joint. A magnetic locking system is embedded inside the module joint. This idea result in lower power consumption when we want to set the position of the module.. Through the complex behavior of SMA and un-repeatability, proposed fuzzy controller has provided better accuracy while consuming a lower energy at the same time.

Keywords:

Modular robotic , shape memory alloy , fuzzy control , position stabilization.