Elektrotechnik und Medientechnik
László Juhász, A. Vujanić, N. Adamović, L. Nagy, B. Borovac
A platform for micropositioning based on piezo legs
Mechatronics, vol. 11, no. Oktober, pp. 869-897
In this paper, we describe the development and prototype testing of a platform for micropositioning having three legs made of piezo tubes. Each piezo tube has four outer electrodes and one common inner electrode on its walls. By appropriate polarization of outer(s) electrode(s) with respect to the inner electrode, due to the inverse piezo effect, the tube wall will change its longitudinal dimension and the tube will bend in the corresponding direction. The platform motion is performed by successive slow bending and quick stretching of the tubes (i.e., legs). At this stage of development, the platform is connected by five wires to a power supply and a PC. The range of platform motion is limited only by the length of the wires connecting it to the power source. Electronic circuits for generating appropriate voltage signals are designed to be as simple as possible. This enabled the complete electronics and microcontroller for motion control to be placed onboard. The microcontroller is capable of realizing all operations needed for the motion execution and the communication with PC (containing the information about motion direction and step amplitude) can be done using a standard RS-232 interface. It was experimentally verified that, though being of a simple design, the platform allows a positioning accuracy which is below Full-size image (<1 K). Even more accurate positioning (below Full-size image (<1 K)) can be achieved in the “only bending” mode by simultaneous bending of all legs in a desired direction and without executing the legs' stretching. The platform capability to accomplish controlled complex motion using different motion velocities was demonstrated. Using a joystick, translation and rotation are easily achievable and the motion can be controlled in real time. Platform loading capacity allows some additional devices like a gripper, or any another device for a particular application to be mounted onboard. This enables the platform's potential use in a wide variety of applications.