Showing papers on "Parallel manipulator published in 1983"
TL;DR: In this article, the authors describe efficient procedures for performing transformations from the position and velocity of the end effector to the corresponding joint angles and velocities, and vice versa, for a six-degree-of-freedom robot manipulator having three revolute joint axes intersecting at the wrist.
Abstract: This paper describes efficient procedures for performing transformations from the position and velocity of the end effector to the corresponding joint angles and velocities, and vice versa, for a six-degree-of-freedom robot manipulator having three revolute joint axes intersecting at the wrist. Some attention is paid to the problems that arise when the manipulator's position is near a deadpoint.
231 citations
22 Jun 1983
TL;DR: In this paper, the authors present an optimal control policy which results in minimum-time motion for a robotic manipulator along any predetermined path in a 3D space, which does not interfere with the manipulator's industrial utility.
Abstract: High speed motions and increased productivity are linked in the industrial applications of many robotic manipulators, yet the speeds which can be achieved by a manipulator during a given task are limited by a number of factors. The dynamic properties of a manipulator and its actuator limitations and characteristics are probably the most important factors. This paper presents an optimal control policy which results in minimum-time motion for a robotic manipulator along any predetermined path in three dimensional space. The technique permits the manipulator user to specify completely the path of the arm; therefore the method does not interfere with the manipulator's industrial utility. The method accounts for the nonlinear dynamics of articulated manipulators with rigid links and limitations on the actuators. These limitations may be arbitrary functions of the manipulator joint positions and velocities. The algorithm developed for obtaining the optimal control is computationally simple, and it does not require the extensive iterations often found in optimal control strategies. Examples are presented of the method's application.
156 citations
70 citations
Patent•
27 May 1983
TL;DR: In this paper, a powered, electromechanical manipulator assembly is described, which includes an electrically powered input device coupled by a hydraulic circuit to a mechanical manipulator, and the manipulator arm is formed of a plurality of modules each having a fixed volume, closed, hydraulic circuit and a slave cylinder.
Abstract: A powered, electromechanical manipulator assembly is disclosed which includes an electrically powered input device coupled by a hydraulic circuit to a mechanical manipulator. The hydraulic circuit is a fixed-volume, closed circuit in which a master piston-cylinder assembly is driven by a D.C. motor and is hydraulically coupled for direct and proportional displacement of a slave piston-cylinder assembly to enable smooth, accurate and easily controlled displacement of a manipulator arm. The manipulator arm is formed of a plurality of modules each having a fixed- volume, closed, hydraulic circuit and a slave cylinder. Both the slave and master cylinders include ambient pressure surfaces which are exposed to the water pressure at the operating depth of the assembly so that variation in depth does not materially affect the response or dexterity of the remote manipulator apparatus. An improved terminal module or jaw assembly is also disclosed.
26 citations
22 Jun 1983
TL;DR: In this paper, a linear analytical model between the six Cartesian errors and the four independent kinds of kinematic errors has been developed and can be used as a guide to minimize the open-loop kinematics errors of the robot manipulator.
Abstract: The correct relationship between two connective joint coordinates of a robot manipulator is defined by four link parameters; one is the joint variable and the others are geomatrical values. Also, the basis for all open-loop manipulator control is the relationship between the Cartesian coordinates of the end effector and the joint coordinates. Hence, the fidelity of the Cartesian position and orientation of the end-effector to the real world depends on the accuracy of the four link parameters of each joint. In this paper, a linear analytical model between the six Cartesian errors and the four independent kinds of kinematic errors has been developed. Based on this model, the Cartesian error envelopes due to any combination of four kinds of kinematic errors can be uniquely determined. From the point of view of design, this error model can be used as a guide to minimize the open-loop kinematic errors of the robot manipulator. Finally, a new calibration technique based on this model has also been developed which can be used to correct the kinematic errors of the robot manipulator.
21 citations
13 Dec 1983
TL;DR: The purpose of robot arm control is to maintain a prescribed motion for a manipulator along a desired trajectory by applying corrective compensation torques to the actuators to adjust for any deviations of the manipulator from the trajectory as discussed by the authors.
Abstract: The purpose of robot arm control is to maintain a prescribed motion for the manipulator along a desired trajectory by applying corrective compensation torques to the actuators to adjust for any deviations of the manipulator from the trajectory. This paper presents various control methods for industrial robots. It begins with the discussion of various dynamic models for manipulators and covers several existing control methods from simple servomechanism to advanced controls such as adaptive control with identification algorithm.
13 citations
TL;DR: The basic ideas of computer-aided design of manipulation robots based on adopted optimizational criteria and on set constraints of strengths, as well as on actuator capabilities are presented.
12 citations
TL;DR: It is shown that the new method proposed in this paper is one of the most efficient when applied on a robot manipulator with successively parallel or rectangular joint rotations.
Abstract: A new method for calculating the Jacobian for a general n degree-of-freedom robot manipulator is presented and compared with some known other methods. The computational efficiency of the method is estimated in terms of the number of multiplications, additions/subtractions, trigonometric functions required, and the execution time on a VAX 11/750 computer. It is shown that the new method proposed in this paper is one of the most efficient when applied on a robot manipulator with successively parallel or rectangular joint rotations.
12 citations
TL;DR: This paper describes a project that addressed teaching a miniature robotic manipulator to play chess by interfacing a Microbot Minimover 5 robot and its Radio Shack TRS-80 control computer to a set of chessboard contacts and a Fidelity Electronics Chess Challenger 7 microcomputer.
Abstract: This paper describes a project that addressed teaching a miniature robotic manipulator to play chess. This task was accomplished by interfacing a Microbot Minimover 5 robot and its Radio Shack TRS-80 control computer to a set of chessboard contacts and a Fidelity Electronics Chess Challenger 7 microcomputer. An extensive control program and interface circuitry were designed to enable each of the major components of the system to electronically communicate with one another.
8 citations
Patent•
28 Oct 1983
TL;DR: In this article, a hand-grip-sensor unit is used to measure forces and torques applied by the operator to the handgrip, and the output of the sensor is connected to the link driving means of the robot via a data-processing unit which converts the output signals from the sensor into data corresponding to forces or torques.
Abstract: There is provided a device for programming motions and operational forces or torques of a robot, and a device for carrying out the method. The device includes a handle grip-sensor unit which includes a known sensor of forces and/or torques of the type which defines a load pick-up plate connected via spokes to a peripheral ring and via upright supports to a rigid base part. The peripheral ring is connected to an inner wall of a hollow body whose outer wall is shaped to match the contours of the human hand. The base part is rigidly connected either to an inertial platform or to an end link of the robot. The output of the sensor is connected to link driving means of the robot via a data-processing unit which converts the output signals from the sensor into data corresponding to forces or torques applied by the operator to the handgrip-sensor unit. The data-processing unit includes an algorithm which converts the output signals from the sensor into drive commands for the joint drives of the robot and adjusts the system of coordinates of the handgrip-sensor unit to the system of coordinates of movements of an actuator on the end link of the robot.
7 citations
01 Dec 1983
TL;DR: In this paper, it is shown how to use a path-controlled manipulator to achieve a swing-free motion for a simply suspended object, where the trajectory consists of an initial acceleration to an intermediate velocity, then a secondary acceleration to final velocity.
Abstract: Objects which cannot be directly grasped by the end effector of a robot manipulator and must be carried by a hook or similar device are susceptible to swinging during transport. For a simply suspended object, it is possible to use a path-controlled manipulator to achieve a swing-free motion. The trajectory consists of an initial acceleration to an intermediate velocity, then a secondary acceleration to final velocity. An experimental demonstration of the method is presented.
TL;DR: A new approach to the geometrical representation of manipulator dynamics is presented, which is applied to aid the design of a mechanical arm, in which dimensions of an arm structure and its mass distribution are optimized through the evaluation and graphical representation of the arm dynamics.
Abstract: Robot manipulators and mechanical arms have complicated behavior including interactions among multiple joints, nonlinear effects such as Coriolis and centrifugal forces, and varying inertia depending on the arm configuration. In this paper, a new approach to the geometrical representation of manipulator dynamics is presented. The inertia ellipsoid, which is used to represent dynamic characteristics of a single rigid body, is extended to a series of rigid bodies in order to represent the manipulator dynamics. The geometrical representation of the generalized inertia ellipsoid (GIE) represents the characteristics of the manipulator as a whole. One can understand the complicated inertia effect and nonlinearity of multi-degree-of-freedom motion by simply investigating the GIE configuration. In the latter half of the paper, the presented method is applied to aid the design of a mechanical arm, in which dimensions of an arm structure and its mass distribution are optimized through the evaluation and graphical representation of the arm dynamics. Keyword: manipulator dynamics, robot arm design, CAD, inertia tensor
TL;DR: Some capabilities of a manipulator with a three-component force sensor which enables one to solve such problems as extraction of workpieces from “bulk”, object contour tracing, etc.
01 Aug 1983
TL;DR: A task board constructed to facilitate time-and-motion studies for remote manipulators and useful in industrial robots programmed to assemble parts.
Abstract: Task board constructed to facilitate time-and-motion studies for remote manipulators. Apparatus equipped with holes, objects of various shapes to be grasped and sensors with switches to indicate contact. Useful in industrial robots programmed to assemble parts.