J. Phys. IV France 11 (2001) Pr8-559-Pr8-564
Position control of a SMA microgripperE. Just1, M. Kohl1 and S. Miyazaki2
1 Forschungszentrum Karlsruhe GmbH, IMT, Postfach 3640, 76021 Karlsruhe, Germany
2 Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
A SMA microgripper system with an integrated optical position sensor is presented. The microgripper consists of two actuation units and an optical slit fabricated from one piece of SMA material with overall dimensions of 2 x 5.8 x 0.23 mm3. The gripper is sandwiched by two substrates with an aligned photodiode and a photosensor, respectively. This transmission setup allows position sensing with a spatial resolution of 1 µm per 2.5% optical signal change. By feedback of the position signal to a PI controller a position error of 0.3% is achieved. The typical time constant for reaching stationary positions is about 140 ms.
© EDP Sciences 2001