구간분할 바이너리 제어를 이용한 3-Finger Anthropomorphic 로봇핸드의 동특성에 관한 연구

Abstract

Development of industrial robot has achieved a new revolution of economic development. Advanced countries have shown the accomplishment of reduction of labor force and improvement of productivity with the introduction of industrial robot. With the development of industrial robot the recognition of robot has been gradually expanded and consequently, in the 21st century, lots of researches on the development of robot evolving around human being are now undergoing. Actuators are key technologies underpinning robotics. The shape memory alloy, piezoelectric ceramic material, air muscle actuator, and electro-active polymer are used as the artificial actuator. Electro-active polymer(EAP) and shape memory alloy(SMA) are non-electromechanical actuators that guarantee soft movement of the robot. In the past, electro-active polymers were used a lot, which could be used for facial muscle or robotic finger that generated relatively fast response speed through mechanical changes like human muscle by electrical force. Hower, the electro-active polymer has problems of difficulty to supply required motor power and heavy weight. The SMA is operated using super elasticity and is used in many fields such as automobile bumper and artificial joint, since it is less burdensome for the changes of environment and weigh. But, the SMA is impossible to restore complex shape and is also difficult to compose the system. In this thesis, the dynamic characteristic of 3-finger anthropomorphic robot hand is studied. The segmented binary control method is proposed for the overcome of the nonlinear dynamic characteristics of SMA actuators. The TEM is used in order to segment the SMA wire. The SMA wire produces displacement in individual segments by heating and cooling control of TEM. To keep constant temperature of the TEM, the metal-oxide semiconductor field effect transistor(MOSFET) is used. The displacement and force produced in each segment by using segment binary control are measured and the possibility as the digital step motor is discussed. The hysteresis characteristics are observed by comparing the segment binary control method with the conventional control method. The temperature control program of segmented SMA wire is developed by using LabVIEW. Temperature control module measures the temperature of TEMs through thermocouple. Relay control module turns on or off the relay by comparing the measured temperature with the threshold temperature. To evaluate the performance of SMA wire using segmented binary control method, the reaction time and the displacement are measured in each segment. TEM which can heat and cold the same surface using the H-bridge circuit is used for segmenting a SMA wire and hysteresis of segmented SMA wire is measured. The hysteresis loop control is used to reduce the latency time of SMA wire according to heating and cooling. The single-axis grouping is used to reduce the control charge of SMA wire. The robotic hand is designed by using ADAMS. By manufacturing the burden robotic hand, the experiment on the dynamical characteristics of the robotic hand is accomplished in the method of segmented binary control.