パラレルリンクロボットを用いた患者体表面における超音波治療器具の面接触制御

Abstract

For ultrasound therapy, e.g. microbubbles delivery, physical contact between therapeutic device and body surface is important. To guarantee the entire contact of the device, we propose a control method considering contact force and reaction moment using a robotic system and sensors. We used a parallel link robot, which has three links and the holder to determine position and angle of the device. First we established a series of surface contact controls, which consists of (a) initial contact control, (b) balance contact control, and (c) angle restoration control. Second we eliminated self-weight moment of the device using the sensors. Next we proposed a measurement method of elasticity coefficient of soft material. Then we performed evaluation experiments using soft material and human body. In the experiment using soft material, contacted area was visualized and evaluated with color ink. In the experiment using human body, convergence time to the desired position and angle was also evaluated while monitoring contact force and moment. We concluded that the determination of appropriate parameters is important and dominant for the quality of the system.