Showing papers on "Articulated robot published in 1996"

Decoupled six degree-of-freedom teleoperated robot system

Abstract: The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device's control of the slave robot to be within imaginary predetermined boundaries.

Six axis force feedback input device

Abstract: The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device's control of the slave robot to be within imaginary predetermined boundaries.

Navigating 3D steel web structures with an inchworm robot

Abstract: We wish to navigate across complicated three-dimensional structures. We describe a robot that can propel itself on a web of surfaces oriented around arbitrary directions in three-space. This robot is an inchworm-like robot with a simple, modular, and flexible design. We present control algorithms for the task-level skills that allow the robot to walk vertically, horizontally, and inverted, and the algorithms that allow the robot to make transitions between surfaces. Finally, we discuss our experiments.

Passive Distance Learning for Robot Navigation.

Abstract: Autonomous mobile robots need good models of their environment, sensors and actuators to navigate reliably and efficiently. While this information can be supplied by humans, or learned from scratch through active exploration, such approaches are tedious and time-consuming. Our approach is to provide the robot with the topological and geometrical constraints that are easily obtainable by humans, and have the robot learn the rest while in the course of performing its tasks. We present GROW-BW, an unsupervised and passive distance learning algorithm that overcomes the problem that the robot can never be sure about its location if it is not allowed to reduce its uncertainty by asking a teacher or executing localization actions. Advantages of GROW-BW include that the robot can be used immediately to perform navigation tasks and improves its performance over time, focusing its attention to routes that are more relevant for its tasks. We demonstrate that GROW-BW can learn good distance, sensor, and actuator models with only a small amount of experience.

Design of a wire-suspended mobile robot capable of avoiding path obstacles

Abstract: The basic structure of a wire suspended robot which 'walks' along an aerial wire is proposed. The design and mechanism of robot legs to walk on a wire using linkage mechanisms is described. A slider-crank mechanism is analysed kinematically and applied to the robot legs. The robot has a gait achieved with the optimum design of the linkage mechanism which enables it simultaneously to avoid obstacles and travel stably. A walking robot was originally designed and constructed according to the evaluation of mobile stability. Experiments were carried out with the designed robot to clarify that the proposed method actually produces a stable walking motion.

Mechatronics for a new robot generation

Abstract: The paper outlines the DLR's mechatronic developments in the robotics area over the last five years. They aim at designing a new multisensory, modularly configurable lightweight robot generation in a unified and integral way. A first step in this direction has been the development of a complex multisensory gripper. It turned out to be a key element in ROTEX, the first real robot in space that flew with shuttle Columbia in early 1993. Sensors and actuators in DLR's new ultra-lightweight robot show up miniaturized integration of mechanics, electronics, and microprocessor control. Joint torque control based on inductive sensing is realized in the compact, highly reducing rotational gearings. With optimized carbon-fiber grid structures, optical high-speed information transfer between the joints and all power and signal electronics integrated into the arm, a new extremely lightweight type of robot arises. Joint control concepts are outlined and a 7 degree-of-freedom version of such a lightweight arm is described. The paper also outlines the concept of the artificial muscle and its use in the fingers of a new modular articulated robot hand. Sensor-based man-machine interfaces and automatic camera guidance by robots in minimal invasive surgery are other topics covered in the paper.

Adaptive fuzzy hybrid force/position control for robot manipulators following contours of an uncertain object

Abstract: This paper proposes an adaptive fuzzy hybrid force/position control scheme, which can force the end effector of robot manipulators to follow the contour of an object in lack of knowledge of the exact geometric shape. The control objective is to perform hybrid force/position control regardless of the existence of the manipulator dynamics. The control algorithm proposed can adaptively update the position trajectory command as well as fuzzy control rules, and consequently, guarantee the global stability and drive the tracking errors to a neighborhood of zero. The present work is applied to the control of a five degree-of-freedom (DOF) articulated robot manipulator. Simulation results show that the proposed control architecture is featured in fast algorithmic convergence.

A fuzzy logic positioning system for an articulated robot arm

Abstract: Articulated robot arms offer maximum positioning flexibility but suffer from complex kinematics. In most applications, linear motion is desirable. Calculating the kinematic equations which govern an articulated arm is straight forward; however, it is generally difficult to calculate the inverse kinematic equations that are needed to position the arm in closed form. Using a fuzzy reasoning system, it is possible to accurately position an articulated arm without explicitly solving the inverse kinematic equations.

An efficient steering control formulation for the articulated body mobile robot “KR-II”

Abstract: This paper introduces an efficient steering control method for the articulated body mobile robot “Koryu-II (KR-II)”. KR-II is a real robot, composed of six cylindrical segments linked in series and has a long snake-like appearance. The main issue on KR-II's steering control is, given from a remote human operator the velocity and orientation commands for the foremost segment, to automatically generate joint commands for all the following segments, such that they follow the foremost segment's trajectory. The derived method is based on a trajectory planning scheme in the inertial reference frame, and is feasible for real time computation. It also presents good energy efficiency and trajectory tracking performance characteristics, and can be extended for KR-II's “W-Shaped Configuration” steering control, which augments the lateral stability of the robot, essential for locomotion over uneven terrain. The validity of these methods are verified by experiments on the mechanical model KR-II.

Designing a behavior of a mobile robot equipped with a manipulator to open and pass through a door

Abstract: One approach of how to pass through a doorway by a mobile robot is discussed. In this task-oriented approach, proposed task is to realize a total behavior with opening a door and passing through a doorway by a mobile robot equipped with a manipulator. In this paper, we described a design of such behavior by a robot, and show a simulation of robot motion series for this task. The key issue for realizing such behavior is cooperation between robot's function sub-systems, such as the locomotion control system, the manipulator control system and the sensor systems.

Calibration free visually controlled manipulation of parts in a robotic manufacturing workcell

Abstract: In this paper we introduce a new approach to visually manipulate, with the aid of a robot manipulator, a part placed randomly on a rotating turntable. The highlight of our approach is that the camera and the robot end effector are both assumed to be uncalibrated. We only assume that the height of the robot end effector is known. Our approach utilizes virtual rotation of the camera via image processing not previously introduced in the literature. Finally, the tracking scheme is implemented by planning the error and gradually forcing it to zero while maintaining the torque controls within acceptable limits. This way we demonstrate a new visually guided analytical tracking scheme.

A two-armed intelligent robot assembles mini robots automatically

Abstract: Fanuc has recently developed an automated assembly system where a newly developed two-armed intelligent robot assembles a maximum of 500 units of mini robots a month, that is to say, one robot builds another robot. By introducing the two-armed intelligent robot, this system has become a universal assembly system for mechanical parts of high variety and small lot production which has previously been considered difficult to automate. This system is also profitable because very few dedicated fixtures for the clamping of parts are needed. The two-armed intelligent robot is equipped with force sensors and a three-dimensional vision sensor at its wrists. This robot has a rail unit, driven by a high speed and high accuracy linear motor.

Coating method of external wall material for corner

Abstract: PROBLEM TO BE SOLVED: To provide a coating method of external wall material for a corner in which even a large exterior material is coated in a narrow working space and also an articulated robot capable of reducing the manufacturing cost of the robot itself is used. SOLUTION: The paint spray pattern of a spray gun 3 is made to be a circular shape and also when the spray gun 3 is moved in the direction leaving the corner part 71 of an external wall material 7, an elbow part 51 is rotated while relatively lowering the wrist part 52 side of an under arm part 5 to the lower part for the elbow part 51 side. When the spray gun 3 is moved in the direction approaching the corner part 71 of the external wall material 7, the elbow part 51 is rotated while relatively raising the wrist part 52 side of the under arm part 5 to the upper part for the elbow part 51 side. COPYRIGHT: (C)1998,JPO

Acceleration and deceleration control method for articulated robot

Abstract: PROBLEM TO BE SOLVED: To provide an acceleration/deceleration control method for articulated robot with which the allowable maximum angular velocity of every driving shaft can be easily derived without pressing the arithmetic part of a controller. SOLUTION: A minimum torque tolerance ξmin is calculated by an unbalance torque Pi and a maximum allowable torque Tsplyi of a motor and a decelerator and while considering inertia Ji for it, allowable maximum angular acceleration αmaxi is calculated. Besides, after estimated maximum angular velocity Vmaxi at an intermediate position θi among plural teaching points set by teaching is calculated based on the recording information of teaching points, an estimated maximum value Cmaxi of centrifugal force and Coriolis force at the intermediate position θi is calculated. In this case, when the estimated maximum value of centrifugal force and Coriolis force is higher than a critical value (Tsplyi -Pi ), the estimated maximum angular velocity Vmaxi is corrected and this value is defined as the allowable maximum angular velocity Vmaxi . Based on the calculated allowable maximum angular acceleration maxi and allowable maximum angular velocity Vmaxi of respective driving shafts, the acceleration/deceleration of articulated robot is controlled.

Drilling device with robot

Abstract: PROBLEM TO BE SOLVED: To provide a drilling device of high workableness and safety operated by a robot in which a drilling operation can be performed in a flexible manner under application of a multi-articulated robot. SOLUTION: A slide base 3 is installed at a wrist 2 of an articulated robot through a force sensor 4. There is provided a motor supporting block 6 slid on a guide rail 5 placed on the base by a pressurized air cylinder 11. A drill device rotated by an inverter motor 7 through a coupling 8 is installed at the supporting block 6. A shock absorber 13 is installed between the motor supporting block 6 and the slide base 3 so as to control the motor 7 and the air cylinder 11 in response to an input of load to the robot with the sensor 4, wherein the air cylinder 11 of the drill device and the inverter motor 7 are controlled in response to the input of load into the robot detected by the force sensing sensor 4 arranged at the wrist are controlled so as to prevent the input for the robot from becoming an overload and at the same time an input of acceleration can be effectively dampened. COPYRIGHT: (C)1997,JPO

Method and device for releasing joint of articulated robot from restraint

Abstract: PURPOSE: To carry out the maintenance and the inspection of the joints of a robot simply and safely, in a method and a device to release the joints of an articulated robot from restraint CONSTITUTION: A motor with nonexciting operation type brake is used to drive the joints, and the restraint of a brake is released by a main loop MBL to feed the current to the exciting coils 21E to 51E of the brake When the brake is being restrained by the main loop MBL, in the method to release the restraint of the joints of a multi-joint robot, an operator selects a motor for rotation of a desired joint whose restraint is to be released And a brake releasing current is fed from an auxiliary loop SBL exclusive for brake releasing connected additionally to the exciting coils 21E to 51E of the main loop MBL, to the brake exciting coil of a motor for rotation of the corresponding joint, so as to release the restraint of the joint of the multi-joint robot

Development of a Snake-like Robot

Abstract: In spite of the wide theoretical capabilities they are attributed, the use of snake-like mobile robots is still limited, partly because the control of such systems is difficult, and requires a high computational cost, even in very simple situations. In this paper we described the design of a wheeled hyperredundant robot that can perform 3-dimensional movements. We also simulated a specific planar movement mode that requires no control of the joints. Both the mechanical and the control structures of the robot were thought as modular for reasons of robustness and convenience of development. The mechanical structure of each module was based on the use of two different mechanical joints: one powerful for the vertical rotation, which was connected with the wheels, and the other for horizontal rotation that could move freely when it was not controlled. This last feature enabled to simulate the considered planar movement. The modular control structure improves the robustness of the robot as it makes self-reconfiguration possible. Finally the simulation showed the fact that using such a planar mode is relevant and requires a few computational cost. Some trajectories of the movement of the robot were numerically investigated.

Screw parts feeder and automatic screw fastening machine

Abstract: PURPOSE: To suck screw parts without stopping a robot and without imparing the characteristics of a horizontal articulated robot and a vertical articulated robot and make common use possible including also a rectangular system robot so as to be high in general-purpose poperty. CONSTITUTION: Screw parts 14 fed from a parts feeder through a rectilinear part 15 are prevented from falling by a fall preventing guide 22. A screw parts feeder 16 is so constituted that the screw parts 14 are regulated in the screw position by a stopper at one screw receiving part 18 rotated by 180 by a rotatory-driving part 21 and that the screw parts 14 taken in first to the other thread receiving part 18 act in such a way as to be positioned below the screw suction part of a robot. A robot having a screw suction part for suction-holding the screw parts 14, and a driver tool for fastening the screw parts 14, held to the screw suction part, to a screwed body is provided with the screw parts feeder 16 in the separately placed state.

Collision-Free Path Planning for Articulated Robots

Abstract: The purpose of this paper is to develop a method of Collision-Free Path Planning (CFPP) for an articulated robot. First, the configuration of the robot is built by a set of robot joint angles derived from robot inverse kinematics. The joint space, that is made of the joint angle set, forms a Configuration space (Cspcce). Obstacles in the robot workcell are also transformed into the Cobstacles using slice projection method. Actually the Cobstacles means the configurations of the robot causing collision with obstacles. Secondly, a connected graph, a kind of roadmap, is constructed by the free configurations in the Cspace, where the free configurations are randomly sampled from a free Cspace immune from the collision. Thirdly, robot paths are optimally determinant in the connected graph. A path searching algorithm based on is employed in determining the paths. Finally, the whole procedures for the CFPP method are shown for a proper articulated robot as an illustrative example.

Calibration method of articulated robot

Abstract: PURPOSE: To provide easy and accurate error detection by comparing an error evaluation reference value based on an error model with an error showing an actual machine to be calibrated while estimating an error of a kinematics parameter by observing variation in position of an end effector of a robot arm. CONSTITUTION: In calibrating an articulated robot A, first, position of an end effector E is fixed at a point in a work space and allows it to perform attitude changing action at an articulated angle obtained in a condition without any error (step I) and change in position of the end effector E caused by an error contained in actual link arm C1 -C3 structure of the robot A is measured (step II). A step III in which this measurement of variation is executed for mode numbers of change in attitude is repeated. Then, termination of the calibration is judged in a step IV and if the judgment is NO, the above operation is repeated until the variation of the end effector becomes certain value or less after a kinematics parameter is calibrated by certain amount.

Articulated robot, driving method thereof, and position detector for robot arm

Abstract: PROBLEM TO BE SOLVED: To improve durability of a robot while reducing a rotation radius of a hand in an articulated robot. SOLUTION: A robot arm 13 is constructed of the first arm 11 and the second arm 12, and the base end part of the first arm 11 is installed in a robot main body 10 freely rotationally. The second arm 12 is installed in the tip part of the first arm 11 freely rotationally, while a hand 14 is installed at the tip of the second arm 12 freely rotationally toward the second arm 12. When the hand 14 is moved from the first position to the second position, the hand 14 is moved so as to be brought close to the main body 10 side, and then, rotationally moved with a reduced rotation radius which is reduced because of the approaching shift.

Design and control of a manipulator arm for a walking robot

Abstract: Many hazardous environments require walking machines which can carry out real work in the event of an emergency. In order to perform these works the machines have to be equipped with light-weight manipulators capable of working with relatively high payloads. In the paper issues associated with the design and control of such manipulators are addressed. This paper is based on the authors' experience with design of a manipulator for the Robug III articulated limb walking robot.

Hardware Standard Design Method with Open System Architecture for Intelligent Robots

Abstract: There are many research approaches to develop intelligent robot. However most of them could not be applied to real tasks. We think it is important to develop a new hardware design concept which includes moduled robot elements and system interfacing flexibility through verious robot developments. Through this concept moduled robot elements which have new open interfaces to be useful for many kind of users were developed. These elements have hierarchical 5 level hardware modules; Mechanism, Servo, I/O, Network, Computer interface. By using this result, we could develop some robot systems, e. g. 7-Axis Manipulator, Under Water Maintenance Robot with Double Arms and Oil-Tank Bottom-Plate Blast Robot, and require some evidences in order to develop robots rapidly. We think our Open System causes many Intelligent Robots to be applied. Because most of intelligent robot researcher can work in own field without robot hardware developments which require much research part.

Automatic cutter for footstep metal-fitting

Abstract: PURPOSE: To remove footstep metal-fittings for a waker to lift and lower in a manhole, without an operator entering the manhole. CONSTITUTION: In a footstep metal-fitting automatic cutter 1, an articulated robot 4 suspended from hoists 3 mounted on a frame 2 is installed, and a camera 37 is mounted on the elbow rotary section 35 of the robot 4. A monitor 23, a robot-control section 22, etc., electrically connected to these hoist, robot and camera are set up on the ground side. An operator can cut footstep metal- fittings without entering a manhole 50 by operating each control section while observing the images of the monitor 23.