Building Linkage Models of Human Arms

在这个项目中，我们开发了一个系统的方法来建立一个人的链接模型的人体上臂，通过他们的运动测量。本文利用三维位置传感器和柔性关节角度传感器对上臂和手腕的运动进行测量。首先，在上臂的连杆模型中引入一个二连杆单自由度机构来描述人体肩部的运动。需要估计链路模型中涉及的个人模型参数，使得模型可以应用于个人。因此，我们已经建立了一种方法来识别模型参数，通过测量的简单运动进行提前。通过测量，可以确定两杆单自由度机构的肩关节中心位置、两杆长度、两关节角度之间的关系、肘关节中心位置、前臂长度等模型参数。传统的单连杆单自由度模型不能同时描述人手的位置和方向，而所提出的模型能够以简单的方式描述它们。此外，可以很容易地将个人之间的差异纳入链路模型中，并且可以通过模型参数的识别来消除传感器位置的差异。其次，我们开发了柔性关节角度传感器来测量人类手腕运动。由于腕部运动的范围是狭窄的，我们已经发现，3D传感器是不适合的手腕运动的测量。因此，我们已经使用应变仪制作了角度传感器的原型，并发现只要手腕角度低于50度，它们就具有足够的精度。如上所述，我们已经发现，所提出的方法是有效的，以建立一个人的上臂模型。构建手腕模型是一个悬而未决的问题。

In this project, we have developed a systematic method to build a personal link model of human upper arms through their motion measurements. A3D position sensor and flexible joint angle sensors are utilized in the measurements of upper arm motion and wrist motion.First, we have introduced a 2-link 1-DOF mechanism into the link model of a upper arm to describe human shoulder motion. It is required to estimate personal model parameters involved in the link model so that the model can be applied into individual persons. Thus, we have established a method to identify model parameters through the measurements of simple motions performed in advance. Model parameters including the location of shoulder joint center, length of two links and the relationship between two joint angles in the introduced 2-link 1-DOF mechanism, the location of elbow joint center, and length of forearm can be identified through the measurements. Traditional 1-link 1-DOF models cannot describe the position and the orientation of human hand simultaneously while the proposed mode is capable of describing them in a simple manner. In addition, difference among individual persons can be taken into the link model easily as well as the difference of sensor locations can be eliminated through the identification of model parameters. Second, we have developed flexible joint angle sensors to measure human wrist motion. Since the range of wrist motion is narrow, we have found that the 3D sensor is inappropriate to the measurements of wrist motion. Thus, we have prototyped angle sensors using strain gauges and have found that they have sufficient accuracy as long as the wrist angle is under 50 degrees. As mentioned above, we have found that the proposed method is effective to build a personal model of human upper arms. Building wrist models is an open issue.