Showing papers on "Articulated robot published in 1993"

Control of Robot Manipulators

Abstract: Control of robot manipulators , Control of robot manipulators , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Robot for guiding movements and control method thereof

Abstract: A robot for guiding movements has its power provided by an operator who handles a tool integral with the robot. Like a conventional robot, the guiding robot has several axes respectively associated with rotation sensors that are connected to a computer system memorizing a path to be followed. When the operator moves the tool beyond the stored path, blocking devices, controlled by the computer system and replacing the robot's motors, prevent the tool from continuing to depart from the path. Thus, at any time, the operator can move the tool within the stored path only. The blocking devices are passive, that is, they are such that they can only resist to a movement but cannot generate a movement, which prevents the occurrence of any uncontrolled movement.

Motorized rotary joint and method of constructing a modular robot utilizing same

Abstract: A motorized rotary joint for robots integrates a joint bearing with a power transmission, such as a planetary type speed reducer, and provides a large central hole for passing electric and service lines therethrough. The rotary joint includes a built-in rotor and stator arrangement within the same joint housing structure, thus allowing the electric motor to share the same bearings and housing structure with the speed reducer. Preferably, the rotor also carries planets of the reducer and the stator is either integral or coupled to a housing of the reducer. The rotary joint also accommodates an encoder, a circuit board having electronic components thereon and a built-in brake to provide a totally integrated, intelligent rotary joint. A method for constructing a modular robot using the rotary joint is also provided, wherein several such rotary joints are coupled to simple structural elements by means of bolted interfaces to construct a multi-joint robot of an articulated structure. Such a modular robot has low cost, is easy to maintain and service, and can be readily and speedily constructed and reconfigured from integrated modular components.

Control system for legged mobile robot

Abstract: A legged mobile robot control system for enabling the mobile robot, more particularly a biped walking robot to walk stably even over terrain with unexpected irregularities. The robot's motion is approximated by a mathematical model and a mathematical control is conducted, while controlling the robot's attitude on the basis of a walking pattern established in advance, without need to use a high-speed on board computer for non-linearlity compensation. In another embodiment made up of a more simple arrangement, when the foot angle deviates from that on flat terrain owing to the foot stepping on a bump, the foot angle is estimated and joints are driven such that the robot's center of gravity is restored in a predetermined target trajectory. In still another embodiment, the robot body's inclination angle and/or angular velocity is determined and the hip joints connecting the body with two legs are driven to restore a predetermined stable attitude.

Locomotion control system for legged mobile robot

Abstract: A locomotion control system of a biped walking robot having a body and two articulated legs including ankle joints and connected to the body. A mathematical model is predesigned to approximate the robot. The mathematical model is assumed to have ideal rigidity and based on the model target angles of the joints including the ankle joints are preestablished in advance. Robot joints are provided with servo motors and control values are determined on the basis of the target joint angles to drive the servo motors to follow the target joint angles. A sensor is provided to detect moment acting on the ankle joints or the legs. The detected moment is multiplied by a gain made up of the reciprocal number of the amount of rigidity of the ankle joints. And based on the product, the control value is corrected so as to compensate the deformation. As a result, the discrepancy between the model and the actual robot is compensated so that, not only the robot can walk more stably, but the freedom of possible compliance control can be increased. Moreover, the legs can have low weight and inertia so that the walking stability can be further enhanced.

Dynamic control approach for motion coordination of multiple wheeled mobile robots transporting a single object

Abstract: This paper proposes a coordinate dynamic control method for the transfer of a common heavy object by several wheeled mobile robots. The coupler, which comprises an active prismatic link and a passive rotary joint, is installed on each robot so that even an ordinary nonholomonic mobile robot with inferior mobility can correctly manipulate the object. A hierarchical coordinative control system composed of a leader and other staff robots is designed to synchronously control the motions of the robots under severe dynamic interactions. The leader robot successively defines the desired motion of the object along its reference trajectory and broadcasts the information to the staff robots. Each staff robot controls the motions of its own body and the onboard prismatic link so as to achieve the desired object behavior without sideways slippages. When the prismatic link approaches the limit for its movement, the staff robot requests the leader to temporarily modify the desired behavior of the object. The control algorithm is formulated on the basis of the kinematics and the dynamics of the wheeled mobile robot. Simulation results illustrate the validity of the method.

Kinematic and Dynamic Properties of an Elbow Manipulator Mounted on a Satellite

Abstract: The discussion in this paper is intended as an introduction to several topics treated in various forms or extensions in the other papers in this issue. Many applications of robots in space require the robot to manipulate a load mass that is not negligible compared to the satellite on which the robot is mounted. In such cases, the robot motion disturbs the position and attitude of the satellite, and this in turn disturbs the robot end-effector position. This implies that the robot joint angles that would normally be commanded to produce a prescribed robot end-effector position and orientation will result in missing the target. In this paper an overview is given of certain engineering problems arising from this phenomenon. The robot end-effector positioning problem is discussed for the two cases of the satellite attitude control system either off or on, and computation of the robot motion disturbances to the satellite is discussed. Shuttle Remote Manipulator System based examples are given.

Navigation control system for mobile robot

Abstract: A system for controlling navigation, more particularly a current position recognition for a biped walking robot in a navigation environment. A map of the environment is prepared in advance. In the map shape features of an object such as stairs are predesignated. The robot has a vision sensor and in its navigation, the robot recognizes its current position from the shape feature. Evaluation functions are also preestablished for selecting one pair among the shape features, which are defined with respect a distance between the object and the robot and an angle determined by a pair of shape features in such a manner that two shape features existing not far from the robot and an angle determined by the two shape features are relatively large. A path is predesignated and robot motion is described in terms of basic walking patterns such as strait forward, direction change and step length adjustment. More specifically, robot joints are driven to realize the described motion such that the robot walks along the path.

An articulated multi-vehicle robot for inspection and testing of pipeline interiors

Abstract: The authors describe the construction of an articulated multi-vehicle robot for inspection and testing of pipeline interiors. The robot is capable of traveling inside pipes of radius 520-800 mm diameter over a distance 150 m. Output pressure versus extension characteristics of the two-stage air cylinder, reduction of the wave reflection in a wheel-type ultrasonic probe, an umbilical cable assembly housing optical fibers, air tubes and electric cables are key elements of the robot. The articulated robot was tested in the laboratory to evaluate and the scanning performance. The results of the non-destructive test of a weld bead to the longitudinal direction show that the robot can pick up surrounding color images and transmit them to the ground station's monitor with high precision.

Robot with dust-free and maintenance-free actuators

Abstract: A robot with no mechanically contacting components are suitable for use in special environments such as semiconductor manufacturing processes where dust and lubrication are matters of important concern. The robot has a linear actuator composed of magnetic bearings and a linear motor for moving a robot arm linearly without mechanical contact, and a rotary actuator composed of magnetic bearings and a rotary motor for rotating a body which supports the linear actuator, around the rotary actuator without mechanical contact.

Towards planning with force constraints: on the mobility of bodies in contact

Abstract: A configuration-space-based approach for analyzing the interactions and mobility of objects in quasi-static contact is described. This analysis is motivated by a class of articulated robot motion-planning problems that are not handled by current planning systems. Examples are a snake-like robot that crawls inside a tunnel by bracing against the tunnel walls, a limbed robot (analogous to a monkey) that climbs a trussed structure by pushing and pulling, and a dextrous robotic hand that moves its fingers along an object while holding it stationary. In these examples, one must plan the robot motion to satisfy high-level goals while maintaining quasistatic stability. Planning the hand-hold states (analogous to the hand-holds used by rock climbers between dynamically moving states) where the robot mechanism is at a static equilibrium is considered primarily. The results obtained are some of the first steps necessary to develop planning paradigms for this class of problems. Although the authors have the general class of quasistatic planning problems in mind, the authors use the language of grasping for discussion. >

A study on the design and control of an articulated hand

Abstract: In many applications, the typical parallel-jaw end-effector of a robot arm has been remarkably satisfactory. But, it is not adequate for the applications such as complicated manipulation. In the study, a finger with 4 joints (so, having redundancy) was consturcted to investigate the characteristics of an articulated hand. Each joint was driven by one actuator, and the motor torque was transmited to each joint through a tendon-pulley system. In the context, major considerations for hardware design and the method to solve the inverse kinematics of a redundant manipulator were presented. Finally, the basic capabilities of an articulated hand were presented through experiments.

Dynamic coordination of multiple robot arms with flexible joints

Abstract: A nonlinear decoupling and linearizing feedback control for dynamic coordination of multiple robot arms handling an ob ject constrained by the environment is considered. A general method is presented that ensures an exact feedback lineariza tion for cases of both rigid and flexible joint arms, as the joint flexibility can cause instability of robotic system control. The method takes the manipulator dynamics and object dynamics into consideration, along with material constraints imposed on the system (mixed contact conditions between arms and object and between object and the environment) and program con straints (specified internal forces, contact forces, and object motion). A method for internal force parameterization, which uses a set of kinematic constraints imposed on the motion of the robot end effectors, is proposed. Control algorithms are developed for redundant flexible joint manipulators designed to have more joints than necessary for given tasks. The appli cation of the control law produces a se...

Method and apparatus for controlling a robot using a neural network

Abstract: A robot controller for an articulated robot, in which a joint angle vector indicating target joint angles of respective joints of the robot is calculated based on a target position matrix indicating a desired target position, and the robot is controlled ill accordance with the joint angle vector. The robot controller is further provided with a neural network for compensating the target position so as to reduce the positioning error. The learning operation of the neural network is repeatedly carried out at predetermined intervals during the operation of the robot. The target position may be preliminarily compensated using a mathematical model.

Method of processing signals within a neural network to position arobot

Abstract: A signal processing method for efficiently searching an optimum solution in a neural network by including a term of a nonlinear resistance in an equation of motion and changing such nonlinear resistance periodically. According to the method, the range of absolute values of connection weights between units in the neural network is limited by the equation of motion, hence preventing a prolonged search time that may otherwise be caused by excessive extension of the search scope beyond the requisite. A plurality of patterns are previously embedded or stored in the neural network and, upon input of a predetermined key pattern, the nonlinear resistance is changed periodically to recall a pattern similar to the key pattern, whereby any desired pattern can be searched or retrieved with rapidity and facility out of the complicated patterns. A process of calculating the next position of an articulated robot corresponding to an optimum solution is repeated while periodically changing a nonlinear resistance included in another equation of the positional energy of the robot, thereby acquiring the data of the robot path up to a desired goal.

Gate cutting device for plastic molded goods

Abstract: PURPOSE:To use a cutting device for the gate parts of plastic molded goods as a conveyor device for the plastic molded goods so as to attain space saving. CONSTITUTION:The gate part of an automobile bumper W transferred onto a supporting device 6 from an injection-molding device 3 by a take-out device 5 is cut/removed by a cutter 37 mounted to the tip of the robot arm 33 by a cutter 37 mounted to the tip of the robot arm 33 of a cutting device 7 formed of an articulated robot. The bumper W cut at its gate part is suction-held by a suction means 40 mounted to the tip of the robot arm 33 and discharged to a transfer device 10 from the supporting device 6. The bumper W is further sent to a stock place by a conveyor device 12. During the cutting work performed by the cutter 37, the suction means 40 is removed from the robot arm 33 and placed on a placing base 9 so as not to be a hindrance to the cutting work.

Control method for articulated robot and articulated robot

Abstract: PURPOSE:To enable positioning with high accuracy even if the arm of a robot is low in stiffness. CONSTITUTION:The robot is so constituted as to allow positioning to be achieved with high accuracy even when a chuck section 7, an arm 6 and the like are vibrated by detecting the action of the chuck section 7 by an inertia sensor 8, and thereby driving arms 4 and 6 based on the output signal 8a of the aforesaid inertia sensor 8.

Learning control of elastic joint robot and its application to the industrial robot manipulator

Abstract: Learning control, a methodology for obtaining a reference input pattern that enables an actual output of a robot manipulator to coincide with a desired one, is modified and applied to a manipulator with an elastic-joint robot. This type of learning control is suitable for actual industrial robot control systems that have independent feedback controllers with each joint. Learning control has been implemented for a single-link elastic-joint robot. Improved high-speed motion has been achieved. Experiments on an industrial manipulator show that the problem of vibration encountered in high-speed motion is mitigated. >

Collision avoidance during teleoperation using whole-arm proximity sensors coupled to a virtual environment

Abstract: This paper describes a collision avoidance system using Whole Arm Proximity (WHAP) sensors on an articulated robot arm. The capacitance-based sensors generate electric fields which completely encompass the robot arm and detect obstacles as they approach from any direction. The robot is moved through the workspace using a velocity command generated either by an operator through a force-sensing input device or a preprogrammed sequence of motions. The directional obstacle information gathered by the WHAP sensors is then used in a matrix column maximization algorithm that automatically selects the sensor closest to an obstacle during each robot controller cycle. The distance from this sensor to the obstacle is used to reduce the component of the command input velocity along the normal axis of the sensor, allowing graceful perturbation of the velocity command to prevent a collision.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Learning of robot biped walking with the cooperation of a human

Abstract: In this paper, the authors devise a method that a biped walking robot realizes a learning process of walking stabilization with the cooperation of a human, by considering the learning process of a baby. The authors developed a biped walking robot which has a trunk. They have equipped the robot with a system for measuring the zero moment point (ZMP) of the robot by using universal force-moment sensors and with a mechanical interface for the cooperation. The authors did walking experiments with the biped walking robot, in which a human directly taught the robot the desired ZMP which makes the walking be stable, and the robot learned to stabilize its walking with the cooperation of the human. As a result, the robot obtained the given desired stability by modifying its trunk motion and it achieved stable walking by itself through the process of several learning trials. This kind of function is integral to an anthropomorphic robot, which the authors call a Humanoid, being a human's partner in the future. >

Constraining the Motion of a Robot Manipulator Using the Vector Potential Approach

Abstract: In a recent work [ 1 ] the authors suggested an-approach based on Artificial Vector Potential Fields to drive a robot along a safe path to a desired destination. In this paper the approach is extended to place constraints on both the position and velocity of the path. Placing a priori known constraints on both position and velocity of a robot is of considerable practical significance for system operation. Previous results are briefly stated, and simulation results are also provided.

Development of model-based remote maintenance robot system. I. Outline of the robot system

Abstract: Describes the outline of a model-based remote maintenance robot system for nuclear facilities such as nuclear power plants and nuclear fusion reactors. This robot system aims at autonomously carrying out maintenance tasks which the operator directs by task-level commands, for example, "set flange" and "set valve". This robot system is composed of a device for measuring the position of the object to be handled, a task planner which generates the robot control program from the task-level command, and an arm controller which moves the arm under either position or stiffness control according to the generated program. In experiments, the robot system carried out the insertion of a bolt and the setting of a nut on a flange.

A formal method to characterize robot reliability

Abstract: The authors have identified robot system failure modes and characterized the robot system reliability using a structure function model from systems theory. To validate this model, a reliability experiment with a laboratory-scale, teach-pendant microbot was conducted assuming independent failures and ignoring induced failures, since they were not observed. Although the method was developed in a laboratory setting with a small-scale robot, the model can be extended to industry-scale robots. The results can provide feedback to the maintenance and supply organization for supporting robot design studies. >

Horizontal articulated robot, arm unit, and machining system

Abstract: PURPOSE: To provide a horizontal articulated robot which is constituted such that even when it is installed, it is prevented from an obstacle on an operator and no adverse influence is exercised on a layout for a machining device, in a horizontal articulated robot formed such that two or more arm units rotatable in a horizontal direction are intercoupled in series. CONSTITUTION: An articulated robot comprises a motor mechanism 12M to drive rotation around an arm unit 12 serving as a fulcrum; a driver to feed a power to the motor mechanism 12M; a control circuit to control the output power of the driver; and a support base plate 11 which is mounted on the arm unit 12, to which a mechanism 11A to ratably support the arm unit 12 is fixed, and the whole of which is vertically mounted. COPYRIGHT: (C)1995,JPO

Double arm mechanism robot

Abstract: PURPOSE: To make an arm formation conformed to the work breakdown realizable and to aim at high output, high rigidity and high precision of robot power by a method wherein plural pieces of robots are provided with plural units of connecting mechanism which partially connects or separated to or from each other and these robots are connected with each other through the connecting mechanism. CONSTITUTION: A robot 1 and a robot 2 travel on a rail 4 separately, rotating respective articulations, and their hands are positioned at the optical location, thereby performing various operations. In the case where such high output work as unable to be done by an independent arm is performed, the robot 1 assumes the same position as the robot 2, and it travels on the rail 4, getting nearer to the robot 2, and a synchronous connection of four connecting mechanisms 23c, 23d, 23e, 23f themselves is thus carried out. With this constitution, force to be added to an arm tip is dispersed in respective articulated axes of both these robots 1 and 2, where double high power is securable as compared with each individual case. COPYRIGHT: (C)1994,JPO&Japio

Self-running robot group system

Abstract: PURPOSE:To measure the expansion position of a self-running robot with high precision even in unknown environment as to the self-running robot group system consisting of plural self-running robots. CONSTITUTION:The self-running robot group system consisting of >=3 self- running robots employs constitution wherein each self-running robot is equipped with a measuring instrument 10 which measures geometrical information on other self-running robots and is equipped with a gathering device 20 which gathers geometrical information on moving self-running robots measured by measuring instruments that >=2 stationary self-running robots are equipped with. Then this system is equipped with a calculating device 21 which calculates position information on the moving self-running robot according to a triangle shape rule by using the geometrical information gathered by the gathering device 20 and the position information on the stationary self-running robot.

An object-oriented approach to robotic motion

Abstract: The authors describe the application of object-oriented design technqiues to the problem of using a pair of heath robot arms to play a game of checkers. They introduce object-oriented design (OOD) and describe some of the strengths and features of this methodology. Brief descriptions of the Heath Robot Arm and of the mathematics of manipulating this robot follow. Finally, the application of OOD techniques to the Robotic Checkers project is presented. >

Door opening/closing controller using robot

Abstract: PURPOSE:To provide a door opening/closing controller of an NC processor without the need of providing a specific actuator for opening/closing a door for extracting a material to be processed of a housing covering the NC processor CONSTITUTION:An NC processor is covered with a housing 1, and a door 5 for extracting a material to be processed is provided on the front surface of the housing so that the door is opened or closed thereby An articulated robot 9 for exchanging materials to be processed is provided in such a way that the robot can be moved laterally along the opening/closing direction The lateral movement function is provided so that a predetermined material to be processed on a stock table, on which the materials to be processed are arranged vertically and horizontally, is gripped by a robot hand A sensor 39 for detecting a dog 45 provided on the door 5, and an air cylinder 43 for linking the door 5 when the dog 45 is detected, are provided on the articulated robot 9, and the door 5 is opened/closed by the lateral movement of the articulated robot 9

Gravitation balancing device, articulated robot, and wrist device for robot

Abstract: PURPOSE:To supply a gravitation balancing device for an arm device driven in the gravitation acting direction such as a robot of multi-joint type, with which the requisite torque of a drive motor is reduced over a wide operating scope. CONSTITUTION:A gravitation balancing device for an arm-shaped member 1 driven by a motor through power transmitting members 6a, 6b, 7, 8 is formed by coupling a plurality of sub-arms 9a, 9b connected thereto with a stationary member 3 through balancing members 5a, 5b. Thereby places on spring members 5a, 5b where generation of force is not possible can be eliminated over as wide an operating scope as 180 deg. from the arm-shaped member 1 being directed up to down, and the gravitation load moment can substantially be canceled regardless of attitude to allow reducing the requisite torque of the motor, and the arm-shaped member 1 can operate at a high speed.