Modeling and Simulation of a Shape Memory Alloy Spring Actuated Flexible Parallel Manipulator

摘要

Parallel platforms are known for its positioning ability. Adding flexibility to a robotic system gives an advantage to better interact with the environment. In this paper a 2 DOF flexible parallel platform has been developed which consist of a triangular top and base plate connected by a universal joint at its centroid. The Shape memory alloy (SMA) springs are used as an actuator because of its large strain and are connected between the top and base plate on all the three vertices of the platform. The top plate provides desired orientation with respect to base plate on SMA actuation. The work intends to understand the system behavior by developing a mathematical model of the system. Two separate models, one to understand the kinematics and dynamics of the platform and other to understand the dynamics of the SMA spring actuator has been developed. The models were then integrated to understand the complete system behavior. The paper focuses on the integration of various system level equations to develop a general model of the SMA actuated platform and the algorithm incorporated for the same has been discussed in the work. The mathematical models were developed in MATLAB/Simulink. The kinematic model of the platform was verified on the experimental set up. The dynamic model of SMA actuator described by Liang was used and the results obtained were found to characterize the SMA. The integrated model simulation results were also verified on the experimental set up.