Akıllı bir eklem için gürbüz denetleme yönteminin tasarlanması ve uygulanması

The invention of biomedical tools has made medical treatments more convenient; however, manual insertion of these tools requires years of practice and erroneous insertion into the body may cause ruptures and bleeding. Employing medical tools with smart joints can improve the medical procedures making them less traumatic. In this work, a shape memory alloy (SMA) actuator based joint, also known as smart joint, is controlled using a discrete-time integral sliding mode (DISM) control to guide the motion of a smart joint. Two Nitinol based SMA actuators are used in an antagonistic arrangement to provide bending motion. The controller is designed on the base of a simplified physical model of a single SMA actuator which eliminates the necessity of obtaining an accurate model. A disturbance observer (DOB) is integrated to the controller to compensate the model uncertainties and external disturbances to the system. The bandwidth of SMA actuator is relatively low. Due to the high sampling time of the hardware that is used, a discrete-time controller was designed. An experimental setup is designed to test the proposed controller with position feedback. In experimental results, DISM controller with DOB is shown to be robust against system model uncertainties and external disturbances. Different frequency responses are compared and it is shown that the response of 0.04 Hz can be achieved with RMS tracking error of 0.0112 radians. Multiple joints connected with rigid links are successfully tracked using Electromagnetic Tracking system as the position sensor.