Title :
Design of shape memory alloy actuator with high strain and variable structure control
Author :
Grant, Danny ; Hayward, Vincent
Author_Institution :
Dept. of Electr. Eng., McGill Univ., Montreal, Que., Canada
Abstract :
A novel shape memory alloy (SMA) actuator consisting of a number of thin NiTi fibers woven in a counter rotating helical pattern around supporting disks is first described. This structure can be viewed as a parallel mechanism used to accomplish a highly efficient transformation between force and displacement. The actuator overcomes the main mechanical drawback of shape memory alloys, that being limited strain. Two variable structure controllers are applied to a pair of antagonist actuators. The first involves a switching control input creating a sliding mode in conjunction with a linear control activated within a boundary layer in the vicinity of the set point. The second involves a multistage switching control that simplifies amplifier construction. Experimental performance results in the time domain are discussed
Keywords :
intelligent actuators; nickel compounds; shape memory effects; titanium compounds; variable structure systems; NiTi; antagonist actuator pair; counter-rotating helical pattern; force-displacement transformation; high strain control; multistage switching control; parallel mechanism; shape memory alloy actuator; thin NiTi fibers; variable structure control; Capacitive sensors; Coils; Counting circuits; Electric variables control; Intelligent actuators; Mechanical variables control; Shape control; Shape memory alloys; Sliding mode control; Strain control;
Conference_Titel :
Robotics and Automation, 1995. Proceedings., 1995 IEEE International Conference on
Conference_Location :
Nagoya
Print_ISBN :
0-7803-1965-6
DOI :
10.1109/ROBOT.1995.525605