Showing papers on "Revolute joint published in 1984"

Obstacle avoidance using an octree in the configuration space of a manipulator

Abstract: An automatic system for planning safe trajectories for a computer controlled manipulator among obstacles is a key component of robot assembly operations. This paper describes an algorithm transforming cartesian obstacles into obstacles in the space of the first three joints of a manipulator with six revolute joints (e.g. a ACMA-CRIBIER V80), and giving a hierarchical description of the free space by mean of an octree. Such a description is very useful in testing for collision between the arm of the manipulator end obstacles since it is represented by a point in this space.

Heuristic combinatorial optimization in the design of manipulator workspace

Abstract: A method for the optimum design of manipulator workspace is provided based on a recently established criterion. Analytical and computer-aided procedures are presented for the determination of the geometrical proportions of a manipulator for optimum workspace. An effective algorithm is developed by combining a heuristic optimization technique and a computer program for kinematic analysis of manipulators. Two problems are investigated. The first is concerned with the optimum design of a manipulator that has three revolute joints and a spherical joint at the wrist, called the RRRS manipulator; the second is concerned with the problem of design improvement for five commercial robots for larger workspace volume. The potential applicability of the procedure is demonstrated.

A numerical solution of the general kinematic problem

Abstract: The paper proposes a method for the solution of the general kinematic problem, i.e. the transformations between the joint coordinate and the cartesian robot coordinate system. Based on homogeneous transformation matrices the method solves the kinematic problem for a series of n (n >/=/< 6) one-degree-of-freedom joints either revolute or prismatic and with or without branching analytically. The inverse kinematic problem is handled numerically via linearization. The numerical solution is evaluated with respect to some constraints like joint workspace, velocities, energy, e.t.c. The numerical results and the computation time show the applicability of the method for real-time control systems.

The Configuration Space Approach to Robot Path Planning

Abstract: Graphically simulated configuration maps are used to plan manipulator paths in two-dimensions. Configuration maps represent a transformation of the Cartesian workspace into the manipulator joint coordinates, identifying both the free space and the space occupied by obstacles. Visual examination of the configuration map allows simulation users to plan collision-free paths by maneuvering the manipulator point along a series of path line segments which connect starting and final manipulator configurations. A PUMA 600 revolute manipulator experimentally verifies one such path planned through a congested workspace.

Solution of kinematic equations for robot manipulators

Abstract: The paper derives kinematic equations of a general robot manipulator presented in the form of an open kinematic chain. Kinematic modelling is based on placing Cartesian-type local coordinate systems on segments of the manipulator and on calculation of their mutual transformations. Equations are written in a form suitable for programming on a digital computer. The given mathematical apparatus represents the basis of a complex mathematical modelling of a robot manipulator and is outstanding for its simplicity, efficiency, and engineering usefulness.

The Mechanical Arm

Abstract: The mechanical arm is the means used by the robot to move its end effector to the desired points, in a manner similar to that of the human arm. Since most of today’s robots are stationary, the arm is generally the only part of the robot that moves. In the future, with mobile robots coming into use, it is possible that additional parts — such as artificial legs — will be called upon to execute motions. This will require the use of mechanical legs (or wheels), additional motors, and the robot “brain” capable of controlling the motion of the mechanical legs as well as that of the arm (arms).

On the Design of Planar Mechanisms with Consideration of Interferences of Moving Links

Abstract: The links of planar mechanism are arranged on some parallel planes, which are called here layers, to avoid their mutual interferences. The minimum number of layers required to construct mechanisms with revolute pairs is determined from incidence matrices. All possible layer arrangements of links under the minimum number of layers are also obtained from the incidence matrices with consideration of full rotations of revolute pairs. A criterion based on layer-distances of adjacent links is proposed to select the best one out of many arrangements. Then, profiles of links are determined with aid of graphic display of relative loci of pairing points so that the links arranged on the same layers may not interfer with each other during a cycle of motion.