Showing papers on "Articulated robot published in 1989"

Task-level planning of pick-and-place robot motions

Abstract: A task-level robot system named Handey, which is under development, is described. The current system is limited to pick-and-place operations, and it has successfully carried out dozens of such operations involving a variety of parts in relatively complex environments. The pick-and-place problem is described, and approximate approaches to the problem are examined. Heuristic motion planning in Handey is then discussed. >

Blanche: Position Estimation For An Autonomous Robot Vehicle

Abstract: This paper describes the position estimation system for an autonomous robot vehicle called Blanche, which is designed for use in structured office or factory environments. Blanche is intended to be low cost, depending on only two sensors, an optical rangefinder and odometry. Briefly, the position estimation system consists of odometry supplemented with a fast, robust matching algorithm which determines the congruence between the range data and a 2D map of its environment. This is used to correct any errors existing in the odometry estimate. The integration of odometry with fast, robust matching allows for accurate estimates of the robot’s position and accurate estimates of the robot’s position allow for fast, robust matching. That is, the system is self sustaining.

Multifingered robot hand with selfadaptability

Abstract: Today, most commercially available robots are equipped with grippers which have two or three rigid fingers. Practical experience has shown that such simplified grippers represent a serious limiting factor for the application of robots to more complex tasks. In order to overcome these difficulties, a gripper of anthropomorphic structure has been developed—the robot hand. This device enables the realization of all basic grasp modes although it is controlled only by three servomotors. The hand is equipped with two mechanisms for selfadaptability which provide for a safe and reliable grasp of the target. The anthropomorphic hand structure is suitable for the implementation of expert control systems. This paper describes the mechanical construction of the hand and its functional performance.

Coupled drive of the multi-DOF robot

Abstract: A robot system design to minimize the robot weight while producing multi-degree-of-freedom (DOF) functioning is proposed. This method aims to couple mutually the degrees of freedom of the robot in such a way that, so far as possible, they can be jointly driven in the robots most common modes of operation. The method is called coupled drive. As an evaluation function for the coupled drive, an actuation index, which is the ratio of the power for the actuation to the whole output power to be provided to the robot system, is introduced. A simulation experiment involving a quadruped walking robot with suckers ascending the vertical surface of a wall is carried out. The experiment deduces by linear programming a walk by which the actuation ratio of the robot is maximized when specific configurations or gaits of the walking robot are given. >

A Wire Mobile Robot with Multi-unit Structure

Abstract: This paper proposes a mechanism and a control system for a wire mobile robot with a multi-unit structure The mobile robot has an ultrasonic sensing system for environment recognition enabling it to move autonomously With this mechanism, control and sensing system, the robot can transfer to a branch wire and avoid obstacles on the wire This paper first clarifies the design of a mechanism and a method for avoiding obstacles and transferring the robot to a branch wire Then it shows experimental results using a prototype of mobile robot with an ultrasonic sensing system

Method of teaching a robot

Abstract: An articulated robot such as an arc welding robot includes a plurality of articulations and an end effector having a tool center point. To teach the robot, a coordinate transformation matrix for transforming coordinates between the articulations is determined from condition data of the articulations. A present position of the tool center point is calculated based on the coordinate transformation matrix and a moving vector is determined from the present position of the tool center point to a next position thereof. Thereafter, a new coordinate transformation matrix for transforming coordinates between the articulations is determined so that the posture of the end effector at the next position of the tool center point, which is calculated based on the first-mentioned coordinate transformation matrix and the moving vector, will coincide with the posture of the end effector at the present position of the tool center point. Then, new condition data of the articulations are calculated from the new coordinate transformation matrix.

Design and analysis of the statically balanced direct-drive robot manipulator

Abstract: A practical architecture, using a four-bar linkage, is considered for the University of Minnesota direct-drive robot (Kazerooni, H., Kim, S.: A new architecture for direct drive robots. In Proc. IEEE International Conference on Robotics and Automation, Philadelphia, Pennsylvania, April 1988). This statically balanced direct-drive robot has been constructed for stability analysis of the robot in constrained manipulation (Kazerooni, H. et al.: Fundamentals of robust compliant motion for robot manipulators. IEEE J. Robotics Automation 2: 1986; Kazerooni, H.: On the robot compliant motion control. ASME J. Dynamic Systems Msmt Control; 111 (3): September 1989. Kazerooni, H. et al.: Theory and experiments on robot compliant motion control. ASME J. Dynamic Systems Msmt Control, June 1990). As a result of the elimination of the gravity forces (without any counterweights), smaller actuators and, consequently, smaller amplifiers were chosen. The motors yield acceleration of 5 g at the robot end point without overheating. High torque, low speed, brushless AC synchronous motors are used to power the robot. Graphite-epoxy composite material is used for construction of the robot links. A 4-node parallel processor has been used to control the robot. A compliant motion control method has been derived and experimentally verified to guarantee stable constrained maneuvers for the robot. As part of the research work, a general criterion has been derived to guarantee the stability of robot manipulators in constrained maneuvers.

Coupled Drive of the Multi-DOF Robot

Abstract: ロボットの機能性向上のためには多自由度化することが不可欠であるしかし, 在来のアクチュエータの出力重量比は著しく制限されている単純な多自由度化はロボット重量の過大な増加を招くそのため機能性を十分発揮し得る軽量で現実的なロボット, 特にこれから必要とされてゆく自律移動ロボットを実現してゆくためには, 従来とはまったく異なる新しい設計手法が必要とされる本研究は, 多自由度化と同時に軽量化も計る新しいロボット設計手法を提案する提案する設計手法は, ロボットに装備する複数の自由度を使用頻度の高い作動状態において出来る限り相互に干渉させ, 共同駆動させようとするものであり「干渉駆動」と呼ぶ干渉駆動によれば, 多自由度的な機能を発揮するために複数のアクチュエータが装備されていたとしても, 各アクチュエータが装備すべき出力容量は低く抑えられるよってロボット本体の重量も軽減できる従来, 制御性の観点からはロボットの駆動系は出来る限り非干渉化すべきであるとされてきた提案する干渉駆動は, 逆に出来る限り干渉化させるべきであることをハードの立場から主張している干渉駆動の評価関数として, 装備すべき全出力パワーに対する作業のためのパワーの比である「駆動率ηc」を導入する干渉駆動の考え方に基づくロボットの機構設計および制御法を検討するため, 4足で壁面を垂直上方に吸着歩行するロボットを想定しシミュレーション実験を行う実験は準静的な運動を対象とし, 歩行ロボットの機構や歩行姿勢が与えられたとき, その駆動率を最大化する歩行を線形画法によって誘導しているこの実験により, 干渉駆動の考え方の導入がロボットの軽量/高速化設計に有効であることを明らかにしている

Design and analysis of a statically balanced direct-drive manipulator

Abstract: A statically balanced direct-drove robot has been constructed for stability analysis of the robot in constrained maneuvers. Using a four-bar linkage, a practical architecture is presented for the University of Minnesota direct-drive robot. As a result of the elimination of the gravity forces (without any counterweights), smaller actuators and amplifiers were chosen. The motors yield an acceleration five times that of gravity at the robot end point without overheating. High-torque low-speed brushless AC synchronous motors are used to power the robot. A graphite-epoxy composite is used to construct the robot links. A four-node parallel processor has been used to control the robot. The dynamic tracking accuracy, with the feedforward torque method as a control law, has been derived experimentally. The compliance and its stability condition have been analyzed and demonstrated experimentally. >

Articulated Body Mobile Robot

Abstract: 多関節構造からなる新しい移動ロボットの提案を行う.提案する形態は車や無限軌道車, 脚方式と並んで移動ロボットを構成する基本形態の一つであり, 特に移動ロボットが狭い空間を多量の物資を積載して移動しなければならない場合に有効である.実際に全6節, 16自由度, 全長1, 391mm, 全重量27.8kgの機械モデルKR-Iを試作し, その駆動制御実験により提案する移動ロボットがある程度の高速移動性と対地適応性を有することを示す.

Compliant motion control for robot manipulators

Abstract: A practical, non-linear controller design methodology is presented for robot manipulators guaranteeing that the robot end-point follows an input command vector ‘closelj’ when the robot is not constrained by the environment, and that the contact force is a function of the same input command vector (used in the unconstrained environment) when the robot is constrained by the environment. The controller is capable of ‘handling’ both types of constrained and uncon5trained manoeuvres, and is robust to bounded uncertainties in the robot dynamics. The controller does not need any hardware or software switch for the transition between unconstrained and constrained manoeuvring. Stability of the environment and the manipulator taken as a whole has been investigated, and a bound for stable manipulation has been derived. For stability, there must be some initial compliancy either in the robot or in the environment. A unified approach to modelling robot dynamics is expressed in terms of sensirivity functions, ...

Horizontal articulated robot.

Abstract: A light, miniaturized horizontal articulated robot capable of being moved in a large space, and fabricated, assembled, maintained and transported at reduced costs. A ball screw (21) in a direct-acting actuator (100) is supported rotatably at its upper end on an upper plate of a column (10), and connected at its lower end to a driving unit (40) provided on a base plate of the column. A first link (220) is connected pivotably to a connecting member (210) of a manipulator (200) fixed to a slider (30) in the actuator, and a second link (240) to the first link. The ball screw is turned by the driving unit to move the manipulator with the slider along the ball screw, and a servomotor (230, 250) for the manipulator is driven to turn the two links in a horizontal plane, whereby robot work is carried out as wrist of the robot is positioned in a robot-provided space. Since a base on which the actuator is supported pivotably is not required, the robot can be made smaller in dimension and weight at a lower cost, and the space of movement of the robot becomes large owing to the low downward movement limit position of the manipulator.

Trajectory planning, optimization and control for industrial robots

Abstract: Following a defined geometric trajectory with an industrial robot requires on-line path generation, coordinate transformation and a suitable closed-loop control. In order to find advanced methods for the process of trajectory planning, optimization, generation and control, a complete robot control system was developed using powerful modern microprocessors. This paper describes the concept and the present state of the project presenting measurement results, obtained with a commercial six-axis robot.

A Robot Control System for Research: ARS/A

Abstract: This paper presents an open architecture robot control system for lower level manipulator control such as motion control or force control. Basically, the system consists of three elements: an industrial robot manipulator called A-HAND, a servo-computer with the motor driver units, and a host computer. The system is called ARS/A (Aoba Robot System for A-HAND). The robot and the servo-computer are regarded as an independent robotic module with a standard interface to the host computer, from which it accepts a set of real time commands to control the robot. Any computer to have the interface may be connected to the robotic module as a host computer. To design the set of real time commands is a crucial issue because it determines the capability and flexibility of the robot system. This paper proposes a set of real time commands which are needed for lower level control experiments. The set was found through experiences. A real time monitor called MOS/A (Motor Operating System for A-HAND) to process the commands to control the robot are implemented on the servo-computer. The MOS commands are defined as functions of a C language on the host computer. The C language is called ARC/A (Aoba Robot C Language for A-HAND) to have other robot control utility functions such as graphic simulation functions as well as the MOS functions. Sample programs show that ARC/A is an efficient programming tool for lower level control.

Cooperative and Learning Control for Complex Robot Systems

Abstract: The control problem of robot systems with unmodeled factors is discussed by using two examples One example of such complex systems is a robot manipulator with Rubbertuators which have complicated dynamical characteristics such as the hysterisis and the compressibility of air Another one is a multi-fingered robot hand manipulating an object under the influence of the task environment The applicability of a learning control scheme to the former and a cooperative control scheme to the latter is examined through several experiments

Articulated robot controller

Abstract: PURPOSE: To move the finger of a robot smoothly as setting the robot at desired posture by finding the joint angles of the robot for plural representiative points in a work coordinate system, and storing them in a table. CONSTITUTION: The joint angles of the robot are found by using an evaluation function to decide the joint angles of the robot for the plural representative points in the work coordinate system, and they are stored in a storage part 4 as table data. A robot arm 7 is driven controllably via a servo control part 6 by prescribed arithmetic processings by a main control part 3 and a subcontrol part 5 based on an inputted targeted value of the work coordinate of a robot finger and storage data stored in the storage part 4. In other words, the joint angle of the robot for a redundant joint is decided with a simple data processing such as an interpolation arithmetic operation, etc., and a remaining joint angle except for the redundant joint can be designated by applying reverse coordinate transformation. Thereby, the robot finger can be smoothly and accurately moved in real time along a targeted locus by operating all joints cooperatively as setting the robot at the desired posture. COPYRIGHT: (C)1990,JPO&Japio

On the Robot Compliant Motion

Abstract: Control The work presented here is a nonlinear approach for the control and stability analysis of manipulative systems in compliant maneuvers. Stability of the environment and the manipulator taken as a whole has been investigated using unstructured models for the dynamic behavior of the robot manipulator and the environment, and a bound for stable manipulation has been derived. We show that for stability of the robot, there must be some initial compliancy either in the robot or in the environment. The general stability condition has been extended to the particular case where the environment is very rigid in comparison with the robot stiffness. A fast, light-weight, active end-effector (a miniature robot) which can be attached to the end-point of large commercial robots has been designed and built to verify the control method. The device is a planar, five-bar linkage which is driven by two direct drive, brush-less DC motors. The control method makes the end-effector .to behave dynamically as a two-dimensional, Remote Center Compliance (RCC).

Experimental Studies of Adaptive Manipulator Control

Abstract: Effective adaptive controller designs potentially combine high-speed and high-precision in robot manipulation, and furthermore can considerably simplify high-level programming by providing consistent performance in the face of large variations in loads or tasks. Previously, a simple, globally tracking-convergent, direct adaptive manipulator controller was derived and demonstrated experimentally. It was then further refined into a “composite” version, whose adaptation law is driven by both tracking error in joint motion and prediction error in joint torques, and therefore represents a combination of a direct and an indirect approach. An effective implementation for multi degrees-of-freedom manipulators was later achieved by developing appropriate recursive algorithms for both joint-space and direct cartesian space control. This paper summarizes the implementation and gives experimental results, performed on a 4-degrees-of-freedom articulated robot arm, verifying the performance of the controller.

Force Analysis of Robot Manipulators

Abstract: The design of a robot manipulator to perform a certain task needs the knowledge of the forces and moments exerted on its joints due to static and dynamic loads. This paper presents a mathematical algorithm for computing the joint forces and moments of the robot arm using the Newton-Euler formulation due to a specified load at its end effector. The computation complexity of an n joint robot arm of a general structure is optimized to need 107n multiplications, 113n additions and 81n equations. A computer program has been developed to perform these computations. Two examples are presented to show the computation procedure: a simple arm of two links and the J PL robot arm of six links. This study is very important for the choice of robot dimensions, the material and shapes of links, and the actuators of joints. It provides the predesign stage of robot manipulators.

Articulated robot for laser work

Abstract: This invention relates to an articulated robot for a laser work which emits a laser beam to a desired position inside a three-dimensional space. The robot includes a robot turning drum (14) fitted to a robot base (12), a first hollow robot arm (16) fitted to the top of the robot turning drum (14) in such a manner as to be capable of rocking, a second hollow robot arm (18) fitted to the tip of the first hollow robot arm (16) in such a manner as to be capable of rocking and rotating around the center axis, and a robot wrist (20) equipped with a condensing unit (22) having a laser emission port (22a) and fitted to the tip of the second hollow robot arm (18). The robot wrist (20) can rotate the condensing unit (22) around one axis orthogonal to the laser emitting direction by converting first and second rotation inputs transmitted through first and second hollow rotation drive shafts (30a, 30b) disposed on the second hollow robot arm (18) by a transmission mechanism and can move back and forth the condensing unit (22) in the laser emitting direction.

Vertical articulated robot

Abstract: This invention relates to a vertical articulated robot which can rapidly calculate each joint angle in accordance with a target position and posture of an end effector and hence, is equipped with offset wrists having high work accuracy. A robot arm consists of first to third links, a joint shaft (YO) of a first joint (1) that connects a base disposed and fixed in a work space to the first link extends in a direction orthogonal to the axis of the base and a joint shaft (Z1) of a second joint (2) that connects the first and second links extends in the axial direction of the first link. A wrist which is offset with respect to the arm is fitted to the third link and the end effector is fitted to this offset wrist. A computer mounted to the robot calculates a first joint angle (Υ1) in accordance with a calculation formula which is established between corresponding transformation matrices for effecting coordinates transformation between the 0th to sixth coordinates systems set to the first to sixth joints (1 ∩ 6) and to the center of the end effector fitting surface and which uses, as its variables, the vector components that represent the origins of the sixth coordinates system in the 0th coordinates system and can be calculated from the target position and posture of the end effector, and the link length and offset distance (d2 ∩ d4) that are determined in accordance with the robot structure. Next, the computer calculates other joint angles (Υ2 ∩ Υ 6) on the basis of the similar calculation formulas.

Reconfigurable articulated robot arm

Abstract: The invention relates to a reconfigurable robot arm having a plurality of articulatedly interconnected rigid components (20, 22, 26, 28), a moving mechanism (12, 14, 16, 18) which gives the robot arm a sufficient degree of mobility, and having control members (32, 34, 36, 38, 42, 44, 46, 48) for controlling the moving system, in which the moving system has a plurality of motor joint mechanisms (12, 14, 16, 18) which each produce one degree of freedom and are interconnected by the rigid components (20, 22, 26, 28), and in which the control members (32, 34, 36, 38, 42, 44, 46, 48) are arranged on the rigid components (26, 28) and control the motor movement of the joint mechanisms in such a way that at least one in each case selectable joint mechanism can be separately controlled for the purpose of configuring the robot arm for the task to be carried out in each case.

Arm fitting structure of horizontal articulated robot

Abstract: A fitting structure of a first arm fitted to a robot base of a horizontal articulated robot, wherein a linearly movable slide is longitudinally guided along the robot base. A base at a base end of the first arm is rotatably fitted to the slider, and rotation of the base relative to the slider is restricted by a removable fixing device. This invention is efficiently used when packaging the robot.

Teaching method for course of robot using force sensor and its device

Abstract: PURPOSE:To make the direct teaching of a course possible even in a vertical articulated robot by fixing a force sensor to a robot arm, and externally providing a command signal generating means. CONSTITUTION:A force sensor 4 on a robot arm perceives force applied to the arm during the moving of the robot, and a command signal generating means 11 generates a command signal according to the magnitude and direction of the applied force on the output signal issued from the force sensor 4 to output the command signal to a robot controller 10. A controlling means then functions to make the robot controller 10 store the command signal to teach the robot its source. In addition, a switching means is operated to release the attitude maintaining force of the robot arm as occasion demands.

Robot controlling method

Abstract: PURPOSE:To enable high speed processing by making a robot and an additional axis operate coordinatively, and in addition, using the same matrix as a transformation matrix at the time when the whole robot is not moved CONSTITUTION:This system is constituted of an articulated robot 11, the robot control device 12 of computer constitution, a teaching operating panel 13, an axis control part 14 and a traveling means 15 Here, the coordinative operation of the robot and the additional axis can be performed, and in addition, the same matrix as the transformation matrix in the case of no additional axis can be used Thus, the time required for transformation processing can be shortened, and high speed traveling comes possible as well

Method of teaching and reproducing operation program for an industrial articulated robot

Abstract: A method of teaching and reproducing operation program for an articulated robot that carries out the operation depending upon the load conditions. A ROM (24) of a robot controller (20) stores a plurality of data tables that determine speed values and acceleration values corresponding to an operation range of articulate drive motors (M theta , MV) depending upon the load weight. The ROM (24) further stores a maximum load inertia determined for the wrist drive motors (M alpha , MZ) and the corresponding servo gain value. In the step of teaching the operation program, the operator sets the load weight as well as load inertia at the time of registering the operation program from a start point to an end point. At the time of reproduction, the corresponding speed value, acceleration value and servo gain are read from the ROM (24) and are automatically set to the servo unit (34).

Optimum movement control system for industrial articulated robot

Abstract: PURPOSE:To quickly perform the robot work by not limiting the speed condition and the time constant of the operation of each robot mobile part to certain values but varying them and calculating the optimum condition and the time constant to generate an operation command CONSTITUTION:An industrial articulated robot 10 has a longitudinal axis 14 stood on a base 12, first and second arms 16-18, and a hand 20 as mobile parts Driving motors M1-M3 are provided as driving sources of arms 16-18 and the hand 20, and their bits of position information are detected by detectors E1-E3 A robot control part 30 is provided with an operation processing device 32 and a storage device 34, and the robot operation command is generated by them and is sent to a servo device 50 The storage device 34 is provided with a means 52 which teaches and sets a program, etc In case of moving operation, optimum speed condition and time constant are controlled and selected before this operation to generate a maximum output torque