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Design of a Parallel Robot Actuated by Shape Memory Alloy Wires
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Terenziano Raparelli1), Pierluigi Beomonte Zobel2) and Francesco Durante2)
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1) Dipartimento di Meccanica, Politecnico di Torino
2) Dipartimento di Energetica, Università di L’Aquila, Roio Poggio
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In this paper the design and the manufacture of a 3-dof (degrees of freedom) robot driven by shape memory alloys (SMA) is presented. This robot has a parallel structure including a fixed plate and a moving plate. The plates are linked together by 3 SMA wires and a mechanical spring is located in the central part. Possible applications are the control devices to orient a mirror, a sample under a microscope or to orient the head of a micro snake like robot. The paper explains the kinematic model, the mechanical design and the control system of the robot. The feedback signals of the closed loop control system are the displacements of the SMA joints located on the moving plate, measured by three conductive potentiometers. The control system is P.C. based. The SMA actuators are driven by Nitinol wires of a diameter of 0.15 mm. The robot takes up a cylinder with a diameter of 100 mm and a height of 180 mm. A prototype of the robot has been manufactured and some experimental tests were carried out. These tests are carried out both using a simple test bed made by a SMA wire and a pulley, and using the prototype itself. The step response of a single SMA wire and the trajectory control to describe a circle in the prototype are also shown as validation tests of the robot. The results of the experimental validation show the feasibility of this design, but particular attention has to be paid to the machining and to the assembly.
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Keyword: shape memory alloys (SMA) actuator, shape memory alloys (SMA) wire, robot design, parallel robot, robot prototype, closed loop control, control design
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Received: December 10, 2001
Accepted: February 15, 2002 ,
Published online: September 06, 2005 |
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Copyright (c) 2005 The Japan Institute of Metals |
 Reference
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