Design and Validation of a Model Free Controller for a Shape Memory Alloy SMA Spring Actuated Redundant Parallel Manipulator

Abstract

Parallel manipulators are class of robot with closed loop kinematic chain popularly known for its precise positioning and handling high payload capability. Parallel manipulators by design enable usage of non-conventional actuators for their actuation providing benefit of miniaturization and better compliance. Such advantage has opened up wide application in the area of micro manipulation devices, flexible robots, development of precise positioning and orienting devices etc. Among the nonconventional actuators, Shape Memory Alloy (SMA) is very popular due to its advantages of clean and noiseless operation, large strain compared to other smart actuators, ease of integration, ease of actuation and high power density. With such advantages, SMA also offers challenges in control due to large hysteresis, low bandwidth, and material property dependency to environmental conditions, aging, fabrication, training methods etc. Hence, SMA based mechanism pose challenges in terms of design and control newline