Design, manufacturing and control of a continuum robotic module actuated by shape memory alloys

Continuum and flexible manipulators have a special role in medical applications. One application is robotic manipulators use for surgery or endoscopic tool use for inspection of body parts like esophagus or colon. In addition to small size, better maneuverability increases the tool performance in real applications. One of the useful actuators in miniaturizing mechatronic systems is shape memory alloys. The material which is usually used as a linear actuator produce high forces in comparison to weight. In this paper, embedding three shape memory springs inside the structure of a flexible module, a two-DOF mechanism is provided. The module has a rigorous usage in modular robotic systems especially flexible manipulators. The developed module produces large deflection in addition to covering a large workspace. Modeling of the module is discussed in this paper for extracting module parameters in design and implementing the simulation. Through the complex behavior of SMA and uncertainty in model, control of SMA is a challenge. In this paper using a novel algorithm, a desired shape for the module is provided. Using the new non model based control approach, the final shape or position is realized. The adequacy of introduced controller is verified through experiments. Large workspace and controllability of module make it feasible for real applications.