Study on environment-adaptive manipulation system

点击翻译按钮获取中文摘要

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.