Hitachi, Ltd.

Shinichi Takarada

Akira Tsuchihashi

Hiroshi Yamamoto

Kichio Nakajima

Taro Iwamoto

Tatsu Aoki

Naoya Ezawa

Satoshi Mohri

Naoki Noguchi

Masahiro Matsuzawa

A manipulator whose economic efficiency and reliability are raised by reducing the size and weight of the system through the backup by a common specification drive circuit and actuator when a fault occurs is provided. Thus, the actuator of the end effector is made so as to have the common structure as the actuators of the multiple joints, so that they are driven by a common specification drive unit. Two systems which can be switched are provided in the actuator of the end effector and additionally, a spare drive unit is provided.

Manipulator

A manipulator, having six degrees of freedom of movement and having a force sensor mounted thereto, is controlled by computing forces and moments applied to the regions of the manipulator from the output of the force sensor. When a force and/or a moment in excess of an allowable load and an allowable load moment of the regions is applied to any region, the joint subjected to the largest load is stopped to save energy consumption of the manipulator. Alternatively by driving the joint in the direction of lessening the load and the load moment, forces and/or moments are prevented from being applied to the regions of the manipulator. Therefore, optimum design is made possible with regard to the strength of the regions of the manipulator and reductions in size and weight of the manipulator can be achieved.

Manipulator and control method therefor

A master slave manipulator system includes a master arm having six or more axes of motion and an articulated slave arm having six or more axes of motion and being shaped in sharp contrast with the master arm. The master arm has an arm body with three axes perpendicular to each other and a wrist assembly connected to the arm body. The wrist assembly has a gripper disposed in a space of a size large enough for an operator to operate the gripper with his clutched hand in X, Y and Z directions and also has a pitch-axis, a yaw-axis and a roll-axis all disposed outside of the space. The pitch-axis, yaw-axis and roll-axis have output axes directed toward the gripper. The slave arm has an arm body with axes longitudinally stretchable or foldable into parallel positions, and a wrist assembly having three axes disposed in a space of predetermined dimensions in X, Y and Z directions. The output axes of the three axes of the slave arm wrist assembly are directed away from the mounting portions of these axes. The slave arm is so controlled as to follow movements of the master arm.

Master slave manipulator system

After positional information of the master arm is transformed into first generalized world coordinates corresponding to positional information representing a calculated position of the slave arm, when a signal instructing an interruption of the associated operation between the master arm and the slave arm is received and then the positional relationships between the master arm and the slave arm connected thereto by use of an imaging device are updated, the first generalized world coordinates are transformed into the second generalized world coordinates based on the new positional relationships so as to restart the associated operation therebetween. The optimal control of the manipulator is conducted through matrix operations related to the change-over between imaging devices, the reset operation conducted in an area of the movable range of the master arm, and the alteration of the ratio between the movements of the associated operation.

Master-slave manipulator control

A manipulator having a plurality of articulations to be controlled with a given destination value of position and orientation, has a finite difference unit for obtaining a finite difference between the destination value and a present value for each articulation, and a fuzzy inference determination unit for executing a fuzzy inference for each articulation by using the finite difference and determining a command value for each articulation. The position of the manipulator terminal may be obtained on the basis of each articulation angle data, video data from a TV camera, or data from an ultrasonic sensor.

A robot system in which a force (torque) exerted on an end effector disposed at an end of a robot to hold an object is sensed to achieve a positioning control. The robot system includes a unit to sense an inertial force exerted on the end effector and the sensed result is fed back so as to remove the influence of the inertia force, thereby effecting an accurate positioning control.

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Yokohama, Japan

Shinichi Takarada