Showing papers on "Robot published in 1984"

Bettering Operation of Robots by Learning

Abstract: This article proposes a betterment process for the operation of a mechanical robot in a sense that it betters the next operation of a robot by using the previous operation's data. The process has an iterative learning structure such that the (k + 1)th input to joint actuators consists of the kth input plus an error increment composed of the derivative difference between the kth motion trajectory and the given desired motion trajectory. The convergence of the process to the desired motion trajectory is assured under some reasonable conditions. Numerical results by computer simulation are presented to show the effectiveness of the proposed learning scheme.

Initial Experiments on the End-Point Control of a Flexible One-Link Robot

Abstract: The present investigation is concerned with initial experiments regarding a specific unsolved control problem which appeared to be central to advances in the art of robotics. This problem involves the control of a flexible member (one link of a robot system). The position of the end-effector, called the end point or tip, is controlled by measuring that position and using the measurement as a basis for applying control torque to the other end of the flexible member, as for instance, the robot's elbow joint. A description is presented of the features of the first experimental arm which has been made, and an outline is provided of the general strategy for controlling it using its tip sensor and shoulder torquer.

Automatic Synthesis of Fine-Motion Strategies for Robots

Abstract: Active compliance enables robots to carry out tasks in the presence of significant sensing and control errors. Compliant motions are quite difficult for humans to specify, however. Furthermore, robot programs are quite sensitive to details of geometry and to error characteristics and must, therefore, be constructed anew for each task. These factors motivate the search for automatic synthesis tools for robot program ming, especially for compliant motion. This paper describes a formal approach to the synthesis of compliant-motion strategies from geometric descriptions of assembly operations and explicit estimates of errors in sensing and control. A key aspect of the approach is that it provides criteriafor correct ness of compliant-motion strategies.

Autonomous mobile robot

Abstract: A vision system for a mobile robot employs at least two arrays of sensors for obtaining data on the position and distance of objects in a workspace. One of the sensor arrays is used principally to see near objects and the other array is used principally to see far objects. The two arrays are symmetric about an axis that extends through the body of the robot. The robot carries a computer which controls the sequence in which the sensors are serially polled for information. Data received from the sensors is stored and provides a representation of the space and objects seen by the sensors. A software program causes the computer to manipulate data from the sensors to simulate rotation of the robot around the axis of symmetry and control behavior of the robot to complete goals set by input commands from a natural language processor.

Multiple robot control system using grid coordinate system for tracking and completing travel over a mapped region containing obstructions

Abstract: A control system for a mobile robot calculates the instantaneous position of the robot, and sequentially stores data representative of the respective robot positions. The system studies and stores a range which the robot is to travel, and calculates a running pattern of the robot in the specific range. The robot is allowed to travel within the range without leaving any region untravelled in spite of the presence of obstructions which alters its path, while checking its own position. Also, the robot compensates for dislocations caused by slippage of its drive wheels or errors in the operation of its motors.

Configuration Design of the Adaptive Suspension Vehicle

Abstract: The selection of vehicle and leg configuration and of power transmission and actuation system configuration for the adaptive suspension vehicle (ASV) are discussed. The ASV will be a proof-of-concept prototype of a proposed class of transportation vehicles for use in terrain that is not passable for conventional vehicles. It uses a legged locomotion princi ple. The machine will not be an autonomous "robot, " in the sense that it will carry an operator. It will, however, have a very high level of machine intelligence and environmental sensing capability. Much of the technology involved is unique and has potential for application to future robot systems. In this paper, major aspects of the vehicle and leg geometry, the on-board processing configuration, and the hydrostatic power transmission system are discussed.

Re-definition of the robot motion control problem: Effects of plant dynamics, drive system constraints, and user requirements

Abstract: The objective of this paper is a redefinition of the robot control problem, based on realistic (1) models for the industrial robot as a controlled plant, (2) end effector trajectories consistent with manufacturing applications, and (3) the need for end-effector sensing to compensate for uncertainties inherent to most robotic manufacturing applications. Based on extensive analytical and experimental studies, realistic robot dynamic models are presented that have been validated over the frequency range 0 to 50 Hz. These models exhibit a strong influence of drive system flexibility, producing lightly damped poles in the neighborhood of 8 Hz, 14 Hz, and 40 Hz, all unmodeled by the conventional rigid body multiple link robot dynamic approach. The models presented also quantify the significance of nonlinearities in the drive system, in addition to those well-known in the linkage itself. Realistic simulations of robot dynamics and motion controls demonstrate that existing controls coupled with effective path planning produce dynamic path errors that are acceptable for most manufacturing applications. Major benefits are projected, with examples cited, for use of end-effector sensors for position, force, and process control that compensate for uncertainties encountered on the factory floor.

An Approach to Automatic Robot Programming Based on Inductive Learning

Abstract: Automatic programming of manipulator robots attracts in creasing interest within the context of mechanical assembly. In this paper we focus on the problem of mating two parts, which requires sensor-based strategies to deal with geometric uncertainty. We present a system that embodies a two-phase approach to build robot programs implementing such strate gies. First a training phase interacts with the robot actuatorsand sensors and produces traces of execution of a given part- mating operation. Next a purely computational induction phase transforms these traces into an executable manipula tor-level program for the operation. The system embedding this approach has been completely implemented, and it has been used experimentally on several assembly tasks.

Strategies for Solving Collision-free Trajectories Problems for Mobile and Manipulator Robots:

Abstract: This article addresses issues involved in programming auto matic solvers for collision-avoidance problems in robotics. It presents a refined notion of empty space and shows that solution methods to...

Motion Planning with Six Degrees of Freedom

Abstract: : The motion planning problem is of central importance to the fields of robotics, spatial planning, and automated design. In robotics we are interested in the automatic synthesis of robot motions, given high-level specifications of tasks and geometric models of the robot and obstacles. The Mover's problem is to find a continuous, collision-free path for a moving object through an environment containing obstacles. This thesis describes the first known implementation of a complete algorithm (at a given resolution) for the full six degree of freedom Movers' problem. The algorithm transforms the six degree of freedom planning problem into a point navigation problem in a six-dimensional configuration space (called C-Space). The C-Space obstacles, which characterize the physically unachievable configurations, are directly represented by six-dimensional manifolds whose boundaries are five dimensional C-surfaces. Implementing the point navigation operators requires solving fundamental representational and algorithmic questions: we will derive new structural properties of the C-space constraints and show how to construct and represent C-surfaces and their intersection manifolds. Originator-Supplied keywords include: Motion planning, Configuration space, Generalized Voroni diagram, Piano mover's problem, Computational geometry, Path planning, Robotics, Spatial reasoning, Geometric modelling, Obstacle avoidance, Geometric planning, Collision avoidance.

Orientation and control system for robots

Abstract: An orientation and control system for use with robots provides identification, orientation and operating instructions coded indicia on diverse parts, which indicia are viewed by a camera and are digital image processor recognizable, so that the indicia are converted into information for computer control of a robot in utilizing the diverse parts in assembly operations. The present system is useful in assembly operations wherein the parts can be randomly presented, without special orientation or alignment fixtures, to a robot and yet the robot can utilize the parts in a programmed manner to perform the programmed assembly operations.

Dynamic visual servo control of robots : an adaptive image-based approach

Abstract: Sensory systems, such as computer vision, can be used to measure relative robot end-effector positions to derive feedback signals for control of end-effector positioning. The role of vision as the feedback transducer affects closed-loop dynamics, and a visual feedback control strategy is required. Vision-based robot control research has focused on vision processing issues, while control system design has been limited to ad-hoc strategies. We formalize an analytical approach to dynamic robot visual servo control systems by first casting position-based and image-based strategies into classical feedback control structures. The image-based structure represents a new approach to visual servo control, which uses image features (e.g., image areas, and centroids) as feedback control signals, thus eliminating a complex interpretation step (i.e., interpretation of image features to derive world-space coordinates). Image-based control presents formidable engineering problems for controller design, including coupled and nonlinear dynamics, kinematics, and feedback gains, unknown parameters, and measurement noise and delays. A model reference adaptive controller (MRAC) is designed to satisfy these requirements.

Computer controllable robotic educational toy

Abstract: An interface receives a high and low voltage signal from a single contact or pin of an output port of a multipurpose microcomputer and uses such signal to control the electrically-powered movement or action of a robot as determined by the programming of the microcomputer. The robot has a sensor connected to the interface and detecting whether or not a preselected condition exists at the robot. The interface sends a high and low voltage input signal to a second single contact or pin of the microcomputer port to communicate the condition of the robot sensed by the sensor. The robot is designed and constructed by the user from interchangeable parts, and the user writes essentially all of the computer programming in a simplified language. By a series of experiments, the student learns computer terminology and programming and robotic technology.

ARM: An algebraic robot dynamic modeling program

Abstract: The computer program ARM (Algebraic Robot Modeler) has been implemented to generate symbolically the forward solution and complete Lagrangian dynamic robot model for control engineering applications. Development and application of this versatile dynamic modeling and control engineering tool are highlighted in this paper. The Q matrix formulation is employed to develop nested iterative algorithms for the symbolic computation of the inertial, centrifugal and Coriolis, and gravitational components of the Lagrangian dynamic robot model. The computational requirements are enumerated as functions of the number of degrees-of-freedom of the manipulator. Automatic generation of the centrifugal and Coriolis force vector dominates the computational load for both state-of-the-art and futuristic robots. The forward solution and complete dynamic model for the three degree-of-freedom positioning system of the Puma robot are exhibited to illustrate the capabilities of Arm. On-going enhancements to ARM are then summarized.

Minimum distance collision-free path planning for industrial robots with a prismatic joint

Abstract: A collision-free path is a path which an industrial robot can physically take while traveling from one location to another in an environment containing obstacles. Usually the obstacles are expanded to compensate for the body width of the robot. For robots with a prismatic joint, which allows only a translational motion along its axis, additional problems created by the long boom are handled by means of pseudoobstacles which are generated by real obstacle's edges and faces. The environment is then modified by the inclusion of pseudoobstacles which contribute to the forbidden regions. This process allows the robot itself again to be represented by a point specifying the location of its end effector in space. An algorithm for determining the shortest distance collision-free path given a sequence of edges to be traversed has been developed for the case of stationary obstacles.

On the design of multi-robot systems

Abstract: For an efficient design of multi-robot systems it is of interest to consider not only parts of the hierarchical structure but to develop a complete control concept including the dynamics of the robots involved. In spite of high practical interest relatively little work has been done on these topics so far. In the paper, the structure of multi-robot systems based on the nonlinear control approach is considered and a design method including the hierarchical coordinator is presented. The new approach is applied to the collision avoidance of two robots working on a conveyor belt with a common working space.

Interchangeable robot end-of-arm tooling system

Abstract: An interchangeable robot end-of-arm tooling system is provided for performing multiple tasks using interchangeable tools within a work cell. The system includes a computer control for the system attached to the robot controller, a quick change adapter, and at least two tools adapted for attachment to the quick change adapter.

DYMIR: A code for generating dynamic model of robots

Abstract: In this paper a program for generating the model of industrial robots in a symbolic form is presented. The program, called DYMIR, derives the motion equations of robots here considered as a chain of rigid bodies connected by suitable single degree-of-freedom (DOF) joints. This is transparent to the user and allows the symbolic calculation of dynamical models until twelve DOF and may take into account elasticity and transmission losses at the joints.

Control system for mobile robot

Abstract: A control system for a mobile robot includes operation means for calculating an instantaneous position of the robot, storage means for sequentially storing data representative of the respective robot positions, means for studying and storing a rangewhich the robot is to travel, and means for calculating a running pattern of the robot in the specific range. The robot is allowed to travel thrpughly in the range without leaving any region non-travelled, while checking its own position.

Linearization and sensitivity functions of dynamic robot models

Abstract: The authors have implemented the computer program Algebraic Robot Modeler (ARM) to generate symbolically the forward solution and complete dynamic robot model for control engineering applications. ARM incorporates the Q-matrix formulation of the Lagrangian (Lagrange-Euler) dynamic robot model. The symbolic formulation of dynamic robot models is extended in two directions: Q-matrices and the Bejczy theorem are applied to linearize symbolically the Lagrangian dynamic robot model about a nominal trajectory; and a methodology is developed to generate symbolically the trajectory sensitivity models of a manipulator with respect to the kinematic and dynamic link parameters. The classical sensitivity point method is thereby extended to include dynamic robot models. Control engineering applications of the linearized and sensitivity models are described. The properties and structural characteristics of these models are identified, and the computational requirements for their implementation in ARM are estimated. The results are illustrated through the double pendulum.

VAL-II: A new robot control system for automatic manufacturing

Abstract: As automatic manufacturing systems become more sophisticated, there is an increasing need for advanced robots which can be easily integrated into the overall system. These robots need to interact with both a supervisory control network and with various sensory devices. VAL-II is a new robot control system and programming language which addresses these needs by supporting network communications, general sensory interfaces, real-time trajectory modification, and concurrent user-program execution. In addition, VAL-II includes high-level computer programming facilities that allow professional programmers to develop special-purpose application programs which simplify the operator interface.

The robot revolution

Abstract: From the Publisher: Robots are making other robots. They've quietly learned how to reproduce. Now they are numerous enough to change forever the way we live and work. In a factory on the slopes of Mount Fuji, industrial robots are now making more robots, working flawlessly around the clock with virtually no human supervision. In Beverly Hills, a robot that normally serves drinks at parties is arrested for handing out business cards illegally in a busy downtown street. From forbidding lunar landscapes to mineral-rich ocean floors, robots perform tasks we thought only humans could do—or could not be done at all. In The Robot Revolution, noted author and computer engineer Tom Logsdon reveals the fact-is-stranger-than-fiction world of robots and the impact they are having in all facets of society, from industry and defense to sports and entertainment. He explores their history from the legendary creations of the ancient Greeks to the experimental ultra sensitive machines of today. And he explains just what robot is and why the latest advances in such fascinating fields as artificial intelligence are making real robots more and more similar to R2D2 and C3P0. Ready or not, The Robot Revolution is here and our lives are never going to be the same again.