Analysis of Grasping Force Control by Human and its Application to Pneumatically Controlled fingers

人类的手指可以轻松地握住各种物体。气动控制方式灵活，过载能力强，清洁度高，防爆安全.因此，为了充分利用流体力学的这些优良特性来加工海产品，本文对人的抓取力进行了实验分析。实验的目的是为了反映气动伺服驱动的机械手指的研制结果，利用手套扫描系统对硬、软、各种物体进行了实验。手套扫描系统具有320个力检测点，因此可以密切研究人类的抓握机制。实验结果表明，拇指尖、食指尖和中指尖对物体的抓取起主要作用。因此，它的结论是，指尖有助于力的调整，在把握的对象。对机械手指进行平行运动以夹持物体，并对机械手指的运动进行了改进，使其能够进行力控制，即只有拇指平行运动，食指和中指指尖可以弯曲60度。通过这些改进，可以实现机械三指抓取控制。但当物体太小时，三个手指不能夹持而趋于封闭，研究发现，如果这些改进的机械手指夹持的物体太小，则需要增加手掌的运动机构，虽然这些问题需要解决，但本研究表明，由气动驱动的机械手指可以实现像人的手指一样的力控制作用。

Human's fingers can easily hold various objects. And pneumatic control is flexible to overload, clean, and safety to explosive environment. So, in order to utilize these good features of pneumatics to process sea foods, the Human's grasping force have been analyzed experimentally. The purpose of experiment is to reflect its results for developing mechanical fingers actuated by a pneumatic servo system.Experiments were made on hard, soft, and various objects by using Glove Scan System. Glove Scan System has 320 force detection points, so it can make possible to closely investigate human's grasping mechanism. Experimental results show that tip of a thumb, a forefinger and a middle finger mainly contribute to grasp object. Thus, it is concluded that fingertips contribute to force adjustment in grasping of the object. The prototype mechanical fingers were moved parallel to pinch object.From this result, the movement of the mechanical fingers have been improved to be able to force control, that is, only thumb finger move parallel, and the tips of the forefinger and the middle finger can be bend at 60 degree. By these improvements, the grasp control is possible to realize by mechanical three fingers actuated pneumatically. But if the object is too small, three fingers could not pinch and tend to enclose it. It is found that if these improved mechanical fingers hold a small object, the mechanism to play the palm of hand should be added.Although these problem should be resolved, this research could show that the mechanical fingers actuated by pneumatics could realize the role the force control like Human's fingers.