This paper describes the architecture and performance of a PC-based configuration controller for dexterous 7-DOF manipulators. The computing platform is a 486-based personal computer equipped with a bus extender to access the robot Multibus controller, together with a single-board computer as the graphical engine, and a parallel I/O board to interface with a force-torque sensor mounted on the manipulator wrist. The Windows environment is enhanced by the iRMX real-time operating system that runs the configuration control algorithms for redundancy resolution. The position control algorithm is executed every 2.5 ms; motions can be simulated and displayed in real-time by the graphical engine on a separate monitor. The results of several experiments carried out with a Robotics Research manipulator have shown motion control capabilities comparable to those obtained with more extensive computing systems, thus validating the use of PCs for dexterous manipulator control. PC-based motion controllers for RRC arms, incorporating the configuration control software, are currently produced by the Robotics Research Corporation.

Control of a redundant manipulator based on an impedance-control framework with multiple simultaneous control sources is described. Each control source provides a different behavior type. An application is decomposed into multiple simultaneous behaviors whose resultant behavior will provide the motion necessary to execute the task. The simultaneous control inputs are merged using impedance control to compute a resultant command to the manipulator. The task space of each behavior can have the dimensionality of the mechanism being controlled. Control of a seven-degree-of-freedom manipulator is described here with an available task space for each behavior of dimensionality seven.

Control software system of seven-degree-of-freedom telerobot designed to elicit maximum performance from minimal, fixed-software computer at remote robot site. Includes multiple control modules, each providing parameter-driven control of specified aspect of behavior of telerobot. Software system runs in Ada language on multiple 68020 processors or potentially on single central processing unit. Conceived for use in outer space, also proves useful in underwater construction and inspection, handling of materials in nuclear facilities, and cleaning up hazardous materials.

Efficient algorithms for forward kinematic mappings of seven-degree-of-freedom (7-DOF) robotic manipulator having revolute joints developed on basis of representation of redundant DOF in terms of parameter called arm angle. Continuing effort to exploit redundancy in manipulator according to concept of basic and additional tasks. Concept also discussed in Configuration-Control Scheme Copes With Singularities (NPO-18556) and Increasing the Dexterity of Redundant Robots (NPO-17801).

Summary A local-remote telerobot control system is described which is being developed for time-delayed groundremote control of space telerobotic systems. The system includes a local site operator interface for interactive command building and sequencing for supervised autonomy and a remote site: the Modular Telerobot Task Execution System ( MOTES ), to provide the remote site task execution capability. The local site system also provides stereo graphics overlay on video with interactive update of the remote environmental model. The operator selects objects in the environment to interact with and skill types to specify the tasks to be performed, such as grasping a module or opening a door.

A telerobot task execution system that has been developed for space station Freedom applications is described. The modular telerobot task execution system (MOTES) provides the remote site task execution capability in a local-remote telerobotic system. The design addresses the constraints of limited computational power available at the remote site control system while providing a large range of control capabilities. The system provides supervised autonomous control, shared control, and teleoperation for a redundant manipulator. The system is capable of nominal task execution as well as monitoring and reflex motion. A command interpreter similar to one used on robotic spacecraft is used to interpret commands received from the local site. Execution utilizes multiple control modules which execute based upon command parameterization. The system controls a seven degree-of-freedom manipulator

Graphics simulation and real-time implementation of configuration control schemes for a redundant seven-degree-of-freedom (7-DOF) Robotics Research arm are described. The arm kinematics and motion control schemes are described briefly. This is followed by a description of a graphics simulation environment for 7-DOF arm control on the Silicon Graphics IRIS Workstation. Computer simulation results are presented to demonstrate elbow control, collision avoidance, and optimal joint movement as redundancy resolution goals. The laboratory setup for experimental validation of motion control of the 7-DOF Robotics Research arm is then described. The configuration control approach is implemented on a Motorola-68020/VME-bus-based real-time controller, with elbow positioning for redundancy resolution. Experimental results demonstrate the efficacy of configuration control for real-time control.< >

Two papers present theoretical studies of older and newer uses for configuration control. control described in Increasing the Dexterity of Robots (NPO-17801) and Redundant Robot Can Avoid Obstacles (NPO-17852). One paper Configuration of 7 DOF Arms reviews these concepts, then applies them to commercial robotic arm having seven revolute joints corresponding to those of human arm. Other paper New Goals for Redundancy Resolution Using Control addresses use of redundant degrees of freedom to optimize dynamical instead of kinematical aspects of performance.

A telerobotics system is described which provides supervised autonomous control capability for time-delayed ground-remote control applications. The system includes a local site operator interface for interactive task description and a remote site task execution system. Interactive stereo graphics overlay on video is provided at the local site to update the remote environment model. The remote site system is capable of nominal task execution, as well as monitoring and reflex motion. Execution utilizes multiple control modules which execute based on command parameterization

The control of a redundant manipulator with multiple simultaneous control sources is described. Each control source provides a different behavior type. An application is decomposed into multiple simultaneous behaviors whose resultant behavior will provide the motion necessary to execute the task. The simultaneous control inputs are merged using impedance control to compute a resultant command to the manipulator. The task space of each behavior can have the dimensionality of the mechanism being controlled. Control of a seven-degree-of-freedom manipulator is described. The available task space for each behavior has dimensionality seven.<>

The Extended Task Space Control approach to robotic operations based on manipulator behaviors derived from task requirements is described. No differentiation between redundant and non-redundant robots is made at the task level. The manipulation task behaviors are combined into a single set of motion commands. The manipulator kinematics are used subsequently in mapping motion commands into actuator commands. Extended Task Space Control is applied to a Robotics Research K-1207 seven degree-of-freedom manipulator in a supervisory telerobot system as an example.

This paper presents kinematic algorithms for resolved-rate based inverse kinematics of redundant manipulators. Efficient and robust Jacobian and weighted damped least squares algorithms are given which provide a method that allows full utilization of the redundancy to best achieve task requirements. A nominal set of task space variables is suggested and procedures for modifying this specification or their relative priorities due to changing task requirements or events are discussed. Examples are shown using a simulation of the seven degree-of-freeom Robotics Research manipulator. These simulations demonstrate the singularity robustness of the algorithms and the ability to smoothly transition between task parameterizations and relative priorities.

This article presents a kinematic analysis of seven-degree-of-freedom serial link spatial manipulators with revolute joints. To uniquely determine the joint angles for a given end-effector position and orientation, the redundancy is parameterized by a scalar variable that defines the angle between the arm plane and a reference plane. The forward kinematic mappings from joint space to end-effector coordinates and arm angle and the augmented Jacobian matrix that gives end-effector and arm angle rates as functions of joint rates are presented. Conditions under which the augmented Jacobian becomes singular are also given and are shown to correspond to the arm being either at a kinematically singular configuration or at a nonsingular configuration for which the arm angle ceases to parameterize the redundancy.

An operational local-remote telerobot system which provides interactive supervisory control of robots which are spatially and/or temporally remote from the local operator station is described. The system has been implemented for the NASA Space Station Freedom engineering prototype development program as a technology prototype dual-arm local-remote system for space telerobotics. The system has two distinct parts: the local site user macro interface for interactive task description and execution, and the remote site task execution system providing single and dual-arm autonomous control. Various time delays can be artificially introduced into the laboratory system to study operations under communication time delay. The remote site of the system and the local site are described. Experimental results are presented. Advanced capabilities currently under development are discussed

The design of the remote site of a local-remote telerobot control system is described which addresses the constraints of limited computational power available at the remote site control system while providing a large range of control capabilities. The Modular Telerobot Task Execution System (MOTES) provides supervised autonomous control, shared control and teleoperation for a redundant manipulator. The system is capable of nominal task execution as well as monitoring and reflex motion. The MOTES system is minimized while providing a large capability by limiting its functionality to only that which is necessary at the remote site and by utilizing a unified multi-sensor based impedance control scheme. A command interpreter similar to one used on robotic spacecraft is used to interpret commands received from the local site. The system is written in Ada and runs in a VME environment on 68020 processors and initially controls a Robotics Research K1207 7 degree of freedom manipulator.

A kinematic analysis of anthropomorphic 7 DOF serial link spatial manipulators with revolute joints is presented. To determine joint angles uniquely for a given end-effector position and orientation, the redundancy is parameterized by a scalar variable which corresponds to the angle between the arm plane and a reference plane. The forward kinematic mappings from joint-space to end-effector coordinates and arm angle and the augmented Jacobian matrix which gives end-effector and arm angle rates as functions of joint rates are given. Conditions under which the augmented Jacobian becomes singular are given and are shown to correspond to the arm being either at a kinematically singular configuration or at a nonsingular configuration for which the arm angle ceases to parameterize the redundancy