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Motion planning for coupled rigid bodies in a horizontal plane is investigated. The rigid bodies are serially connected by passive revolute joints. The dynamic constraints on the system are second-order nonholonomic constraints. We attempted to control those n coupled rigid bodies by the translational acceleration inputs at the first joint. If each rigid body is hinged at the center of percussion, it is possible to compose a positioning trajectory by connecting rotational and translational trajectory segments. Each rigid body can be rotated about its center of percussion one after another. When all of the rigid bodies are aligned on a straight line, they can be translated. The algorithm for positioning is presented. Simulations show that the coupled planar rigid bodies can reach the desired configuration by the constructed inputs. KEY WORDS—coupled rigid bodies, passive revolute joints, nonholonomic motion planning, positioning, second-order nonholonomic constraints, underactuated system 1

Physical and affective interaction between human and mental commit robot

Abstract: Recent advances in robotics have been applied to automation in industrial manufacturing, with the primary purpose of optimizing practical systems in terms of such objective measures as accuracy, speed, and cost. This paper introduces research on mental commit robot that seeks a different direction that is not so rigidly dependent on such objective measures. The main goal of this research is to explore a new area in robotics, with an emphasis on human-robot interaction. In the previous research, we introduced a cat robot and evaluated it by interviewing many people. The results showed that physical interaction improved subjective evaluation. However, some subjects gave severe comments on structure of the cat robot when they interacted with it physically. Because of appearance of cat robot, subjects associated with a real cat depending on their own experiences and knowledge, and then compared the robot with real cat. This paper investigates influence of a priori knowledge into subjective interpretation and evaluation of mental commit robot. We developed a new seal robot that has appearance of a baby of harp seal. Most people did not know harp seal precisely nor have experience of interaction with it. Then, subjects evaluated the seal robot while interacting with it

Dynamic Control of a Manipulator with Passive Joints in Operational Space

We present a method to control a manipulator with passive joints, which have no actuators, in operational space. The equation of motion is described in terms of operational coordinates. The coordinates are separated into active and passive components. The acceleration of the active components can be arbitrarily adjusted by using the coupling characteristics of manipulator dynamics. This method is also extended to path tracking control of a manipulator with passive joints. A desired path is geometrically specified in operational space. The position of the manipulator is controlled to follow the path. In this method, a path coordinate system based on the path is defined in operational space. The path coordinates consist of a component parallel to the path and components normal to the path. The acceleration of the components normal to the path is controlled according to feedback based on tracking error by using the dynamic coupling among the components. This in turn keeps the manipulator on the path. The effectiveness of the method is verified by experiments using a two-degree-of-freedom manipulator with a passive joint

Path Tracking Control of a Manipulator Considering Torque Saturation

When the minimum-time trajectory of a manipulator along a geometrically prescribed path is planned taking into consideration the manipulator's dynamics and actuator's torque limits, at least one of the joints should be at the torque limit. The execution of such a trajectory by a conventional feedback control scheme results in torque saturation. Consequently, the tracking error cannot be suppressed and the manipulator may deviate from the desired path. In this paper, we propose a feedback control method for path tracking which takes the torque saturation into account. Based on the desired path, a coordinate system calledpath coordinates is defined. The path coordinates are composed of the component along the path and the components normal to the path. The equation of motion is described in terms of the path coordinates. Control of the components normal to the path is given priority in order to keep the motion of the manipulator on the path. Simulations of a two-degree-of-freedom manipulator show the effectiveness of this method

Manipulation and active sensing by pushing using tactile feedback

Abstract — We investigate manipulation and active sensing by a pushing control system using only tactile feedback. The equations of motion of a pushed object are derived using a model of the object’s limit surface, and we design a control system to translate and orient objects. The effectiveness of the proposed controller is confirmed through simulation and experiments. Active sensing of the object’s center of mass is described. I

Dextrous Manipulation Planning by Grasp Transformation

A novel framework for dextrous manipulation planning based on transformations between canonical grasp con- gurations is proposed in this paper. The proposed approach is inspired by the observation that human hand is capable of a large number of manipulative tasks with a few nger postures or grasps. It is postulated that the key to the control of manipulation tasks, therefore, lies in the combination of these grasps. The proposed framework rst identies important or canonical grasps, dened in terms of contact pairs between topological features (TF's) of the hand and the object, and then obtains the possible transitions between the grasps. With the result expressed in the form of a grasp transformation graph, general manipulation tasks can then be planned by searching the graph for a path connecting the initial and nal congurations of the tasks. The proposed approach is demonstrated by experiments using a three-nger hand performing object manipulation tasks. 1 Introduction Contr..

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