The problem of controlling two cooperating robot arms is investigated. The task is to move an object from one place to another by grasping it at two different points using two robot arms. The path of the object is determined first in the Cartesian coordinate system, and the corresponding joint variable trajectory is evaluated from the object path for each robot. Each robot is then position controlled so that it follows its joint variable trajectory. The method was successfully applied to two RHINO robot system.

Part 1 of the paper* was concerned with the Jacobian of serial robot-arms and its matrix of cofactors; part 2 emphasizes the end-effector's velocity characteristics as affected at special configurations. The displacement about a ‘fixture-point’ is extended dually to a ‘fixture-plane’, and then to a ‘fixture-line’. These fixture-elements serve to highlight the prolixity of special configurations. Reciprocal screws lead to a complete survey of how the end-effector can ‘twist’ when one freedom is lost; extension to loss of more freedoms is explained. Then the fixture-elements are given elementary displacements that allow common requirements to be studied with the minimum of complications. Further investigation is thought to have promise for robot-control.

This paper investigates the kinematics and motion of a human arm as a manipulator with seven degrees of freedom, and how to deal with the extra degree of freedom that exists. It proposes that a change of configuration be divided into a sequence of motions where each time one of the joints is locked. It then presents a general technique to solve inverse kinematic equations of the different reduced models that arise.

A direct subspace of a dynamic three-dimensional joint space is found to be useful for robot path planning in workspaces comprised of both static and dynamic objects. Dynamic descriptions permit positioning tables, automated guided vehicles, conveyors and cycling machine tools to be modeled by elements which translate or cycle along rectilinear paths. Graphical path planning procedures use cursor indicators to move the robot configuration point between the desired starting and final configurations while avoiding both the static and dynamic joint space obstacles.

The need to store the trajectory information required by industrial robots, so that they may carry out tasks such as painting, has led to various data compression methods. The method proposed, simple to implement and adaptable to low cost systems, enables a best compromise to be reached for a given application between the detailed description of a complex movement and the use of as little memory as possible. This method was first used on a hydraulic prototype for the French Master-Slave firm PHAREMME.

Path planning a robot arm motion essentially requires that the constraints of the joint variables and the vector of the joint motion rates are taken into account. In order to satisfy the constraints of the joint variables a sliding mode is being employed together with the developed kinematic path control method. The extended form of the kinematic path control method, here proposed, treats simultaneously the constraints of the joint variables and the vector of joint motion rates in path planning a robot arm motion.

Let P = {p1, …,pn} and Q = {q1,…,qm} be two simple polygons in the plane with non-intersecting interiors, the vertices of which are specified by their cartesian coordinates in order. The translation separability query asks whether there exists a direction in which P can be translated by an arbitrary distance without colliding with Q. It is shown that all directions that admit such a motion can be computed in O(nlogm) time, where n > m, thus improving the previous complexity of O(nm) established for this problem. In designing this algorithm a polygon partitioning technique is introduced that may find application in other geometric problems.

The algorithm presented in this paper solves a simplified version of the grasping problem in robotics. Given a description of a robot hand and a set of objects to be manipulated, the robot must determine which objects can be grasped. The solution given here assumes a two-dimensional world, a hand without an arm, and grasping under translation only.