Study of technical aid-for disabled person utilized hydraulic bilateral servo mechanisms

在照顾卧床不起的老人时，最困难的动作是抬起身体的动作，如洗澡、换尿布和下床。虽然有一个配重升降器和一个电机升降器，但由于开关操作和支持老年人姿势的动作同时进行，所以操作开关需要两个以上的助手。本研究通过引入双侧伺服系统的力反馈伺服系统，对包括电机为强力动力源的双侧伺服传力机构进行了系统化，并通过双侧力反馈伺服系统实现了油压的平滑。结果：1997年，我们试制了主从侧均用的三种油压缸(phi20、phi30和phi50)，其中包括一个压力传感器和一个位移传感器。在此基础上，设计了电机旋转力与主侧活塞通过直线驱动机构直接连接的一体化结构。结果表明，在缸径为phi30的16瓦交流电机组成变速箱(减速比：25)的双向伺服系统时，可以以1.8赫兹的速度上下移动40kgf重量。在位置控制方面，采用了对称的双侧伺服系统，构成了力反馈的双侧伺服系统。结果：在1998年的第二年，我们在PC机上更换了一个伺服系统，取得了用一根手指举起5Okgf重量的效果。我们刚刚构建了一个具有3个自由度的多用途机器人。有趣的是，由于开环运动在没有反馈信号的情况下非常稳定，我们通过获得平稳的运动确认了助力源作为福利装置。

The most difficult movements in care for old people confined to bed are motions to lift up a body such as bathing, changing a diaper and moving from bed. Although there were a lifter by counter-weight and a lifter with electric motor, more then two helpers were needed in the method to operate a switch because the switch operation and movements supporting a posture of old person were done at the same time.In this research, we have proceeded with a systematization of a force transfer mechanism by bilateral servo including motor as a strong power source and smoothness of oil pressure by introducing force feedback servo of bilateral servo system.Results in 1997 :In the first year, we manufactured by way of trial three kinds of oil pressure cylinders (phi20, phi3Oandphi50)using in both master and slave sides, which included a pressure sensor and displacement sensor. And then, we designed integration structure connecting motor rotational forces with a piston of master side directly though straight driving mechanism. As a result, we could move up and down 40kgf weight at 1.8Hz speed when composing bilateral servo system of gear box(reduction ratio : 25)by using AC motor of 16 watts in cylinder diameter ofphi30. In the case of position control, we use a symmetrical bilateral servo constructing a force feedback bilateral servo system.Results in 1998 :In the second year, we changed a servo system on personal computer and then obtained the result lifting up 5Okgf weight by one finger. We have just constructed a multipurpose robot with 3 degrees of freedom.As an interesting result, we confirmed a power assisting source as a welfare device by obtaining smooth motions because open loop movements are extremely stable in condition without feedback signal.