Study on environment-adaptive manipulation system

机器人在现实世界中执行任务需要对外部环境的自我识别和对未知环境的适应性接触。这些研究中使用的系统包括视觉传感器和工作部件，如机械手和手，其中视觉传感器的数量和布局根据其目标而变化。视觉伺服系统有两种类型：“眼在手系统”是将视觉传感器放置在机械手末端的系统，“眼-手系统”是将视觉传感器与机械手分开放置的系统。使用后一种系统，我们可以获得像人眼一样的广阔前景，并可以客观地看到工作环境，包括其终点。然而，在控制系统方面，机械手的控制是基于利用图像信息计算出的目标的三维位置进行的，因此系统容易受到摄像机标定误差的影响，不能完成高位置精度。通过通用摄像机组成的主动视觉系统协同控制机械手跟踪运动目标，并在接触后利用环境自适应的力控制系统实现对目标的抓取。为了实现稳定抓取，提出了变刚度矩阵柔度控制系统，并对应用该方法的多指机器人手进行了实验研究，得到了以下结论。通过改变剪切方向力作用下的关节刚度，获得了适应质量变化的抓取控制系统。在摩擦锥体内部设置合适的指力区域，通过约束该区域的力向量，实现了适当力的抓取。

Self-recognition of external environment and accommodative contact to unknown environment are required for robots to carry out tasks in real world. Systems used in these researches consist of vision sensors and working parts such as manipulators and hands, where the number and the layout of vision sensors vary depending on their goal.There are two types of visual servo systems; "eye-in-hand system" is the one with vision sensors placed at the end point of the manipulator, and the "eye-and-hand system" is the one with vision sensors placed separately from the manipulator. Using the latter system, we can obtain a broad outlook as with human eyes and can take an objective view of the work environment including its end point. In terms of control system, however, the manipulator is controlled based on 3D position of the target calculated using the image information, and therefore, the system is vulnerable to the effect of camera's calibration error and can't accomplish high position accuracy.In this research, we constructed the eye-and-hand system having configuration close to human for accomplishing various tasks in real world. The moving target is tracked by cooperatively controlling the manipulator with the active vision system consisting of general-purpose CCD camera, and after the contact is achieved, we aimed to grasp the target using the environment-adaptive force control system. Compliance control system with variable stiffness matrix is proposed to achieve stable grasp, and by handling the experiment using the multifingered robot hand, which this method is applied to, we obtained the following conclusions.1. By changing the joint stiffness due to the shear direction force, the grasp control system adaptable to mass change was attained.2. Area of appropriate finger force was set inside the friction cone, and by constraining the force vector in that region, grasp with appropriate force was achieved.