Showing papers on "Articulated robot published in 1998"

Redundancy problem in writing: from human to anthropomorphic robot arm

Abstract: This paper presents the analysis of motion of a redundant anthropomorphic arm during the writing. The modeling is based on the separation of the prescribed movement into two motions: smooth global, and fast local motion, called distributed positioning (DP). The distribution of these motions to arm joints is discussed. It is based on the inertial properties and actuation capabilities of joints. The approach suggested allows unique solution of the inverse kinematics of redundant mechanisms such as human arm and anthropomorphic robot arm. Distributed positioning is an inherent property of biological systems. Humans, when writing, as shown in literature and in our earlier work control their proximal joints, while the movement of distal joints follow them (synergy). To enhance capabilities of robots, new control schema are necessary. We show that robot control can be improved if it is biological analog. The major aim of this study is to promote such a hypothesis by using anthropomorphic robot arm in writing as an example.

Research on a six-legged walking robot with parallel mechanism

Abstract: A new lightweight six-legged robot is developed which uses a simple mechanism and can move and work with high efficiency. This robot consists of two leg-bases with three legs each and walks by moving each leg-base alternately. These leg-bases are connected to each other through a 6-DOF mechanism. Thus, when the robot stands on three legs, or one leg-base is placed on the ground, the other leg-base can be used as a 6-DOF manipulator or active working platform. The output force, velocity, and movable range of various mechanisms for connecting the two leg-bases were compared and the results showed that good performance could be achieved with a serial-parallel hybrid mechanism consisting of three 6-DOF serial linked arms positioned with radial symmetry about the center of each leg-base, each composed of two active and four passive joints. Walking experiments with this robot confirm that this mechanism has satisfactory performance not only as a walking robot but also as an active walking platform.

Biped-type leg-wheeled robot

Abstract: Biped-type leg-wheeled robot Osamu Matsumoto a , Shuuji Kajita b , Muneharu Saigo c & Kazuo Tani d a Mechanism Division, Robotics Department, Mechanical Engineering Laboratory, 1-2 Namiki, Tsukuba, Ibaraki 305-8564, Japan b Mechanism Division, Robotics Department, Mechanical Engineering Laboratory, 1-2 Namiki, Tsukuba, Ibaraki 305-8564, Japan c Mechanism Division, Robotics Department, Mechanical Engineering Laboratory, 1-2 Namiki, Tsukuba, Ibaraki 305-8564, Japan d Department of' Information Science, Gifu University 1-1 Yanagido, Gifu 501-1193, Japan Published online: 02 Apr 2012.

Artificial potential method for control of constrained robot motion

Abstract: The artificial potential method of constrained robot control is presented. The method does not imply knowledge of a detailed robot model and, nevertheless, makes it possible to drive a robot in the environment with obstacles of any shape and along a desired trajectory as well as to take into account constructive constraints. The method is based on the construction of an artificial potential that provides the absence of intermediate equilibriums in which the robot can be locked.

Analysis and implementation of observers for robotic manipulators

Abstract: Different solutions to the robot control problem by using only position measurements have been studied in literature. The performances of some linear and nonlinear observers previously proposed are discussed in this paper, on the basis of the experimental results obtained in the control of a SCARA two-link manipulator with two revolute joints. The comparison is carried out by using the observed velocities to implement a linear state feedback algorithm for the robot control. The obtained results show that different factors (e.g. the required task, the available knowledge of the robot dynamic model) may influence the choice of a particular observer.

On sensor-based roadmap: a framework for motion planning for a manipulator arm in unknown environments

Abstract: We present a general framework for sensor-based motion planning for an articulated robot arm with many degrees of freedom. We assume a sensor that measures distances in physical space (a range sensor). Inspired by recent work in classical motion planning, the crux of our framework is to represent the connectivity of the configuration space (C-space) with a graph structure, the roadmap. This roadmap is then incrementally built. We have performed some simulations that show the promise of our approach.

Task-oriented programming of large redundant robot motion

Abstract: Large robots are a new domain of advanced robotics. Examples of their application fields are tasks like operations on large free-form surfaces, especially aircraft cleaning and removing paint from hulls. They are equipped with a programmable robot control comparable to a control system used for industrial robots. However, conventional teach-in methods are not able to manage the complexity of programming large redundant robot operation on free-form geometries. The Fraunhofer IPA has developed an innovative off-line programming system that allows the creation of robot motion programs which satisfy time and energy optimization criteria. This system helps to avoid collisions within the workspace and to fulfill conditions that arise from the robot kinematics and dynamics. This advanced programming system has been successfully used to generate motion programs for the world’s largest mobile robot, the aircraft cleaning manipulator SKYWASH. In this context offline programs for eleven different types of aircraft have been developed.

Tea serving robot suspended from ceiling

Abstract: A suspended-from-ceiling type tea serving robot for household use is proposed in this paper. The duty of the tea serving robot is to serve a drink to a bedridden person. A bedridden person can order the robot to bring a cup of tea without hesitation, and therefore can avoid his dehydration. A hand of the robot is suspended from a ceiling, of a house, and driven three dimensionally in the orthogonal coordinates. No installing area is required to utilize the robot because of the suspended structure from a ceiling. The hand swings as a pendulum. A vibration reducing control is proposed to decrease the hand vibration. The swing of the hand is detected by a swing angular detection system. The tea serving experiments are carried out. The robot will be sure to carry the filled teacup without spilling out its contents.

Biped robot to assist walking and moving up-and-down stairs

Abstract: A biped robot technology for household use is proposed in this paper. The motivation of the biped robot is to assist an aged person with an unsteady walk in walking and moving up-and-down stairs. The robot has two legs with waist, and its waist is fixed to a handrail of a house using linear guides. The robot is able to walk by supporting itself on the handrail. A control bar is attached to the robot waist. An aged person can easily walk and move up-and-down stairs by stepping onto the feet of the robot. The robot structure using the handrail is advantageous since it allows for a compact, lightweight, and low cost robot mechanism. A scaled down biped robot was fabricated in order to confirm the proposed principle, and the simulation study was also carried out.

Standing-on-floor type tea serving welfare robot using voice instruction system

Abstract: A tea serving robot for bedridden people is proposed in this paper. The tea serving robot is a standing-on-the-floor type with light weight, requiring a small installation area, and can be easily moved. A robot arm and hand can grasp a tea cup and carry it three dimensionally. A weak stiffness cantilever arm is used as the robot arm in order to ease bedridden people's tension. The bedridden person can easily catch and stop the robot arm and hand. The vibration reducing control of the robot arm is considered. The tea serving robot is actuated following the voice instruction. Therefore, the bedridden person can easily order the robot to carry a cup of tea.

Automatic computing method of load weight and load center-of-gravity position of articulated robot

Abstract: PROBLEM TO BE SOLVED: To provide a method of automatically computing the weight and center-of-gravity position of load at the arm tip of an articulated robot without using a force sensor. SOLUTION: In a method of computing the weight and center-of-gravity position of load positioned at the arm tip of an articulated robot provided with a plurality of driving shafts driven by a servo motor, an action pattern program is prepared (step 12) on the basis of a reference attitude taught by a teaching device (step 11), and the articulated robot with specified load at its arm tip is put in action according to the action pattern program (step 11), and the articulated robot with specified load at its arm tip is put in action according to the action pattern program (step 13). During this action, the driving current of the servo motor driving each driving shaft is detected every preset scan time (14). The average value of torque applied to each driving shaft, computed on the basis of the average value of detected driving current on each driving shaft, is made equivalent to unbalance torque applied to each driving shaft so as to compute the weight and center-of-gravity position of load included as an unknown quantity in unbalance torque (step 15).

Reference attitude determining device for industrial robot

Abstract: PROBLEM TO BE SOLVED: To easily determine a reference attitude, so that the reference attitude of a robot set up in a manner of wall mounting and hanging can be also easily determined. SOLUTION: A jig 7 secured to a six-axis articulated robot base 1 has two tapered holes 7a. A jig 6 mounted in a robot wrist 5 is provided with two tapered shaft parts 6a fitted to the tapered hole 7a. By fitting the two tapered shaft parts 6a to the tapered hole 7a, a robot attitude is uniformly determined, and a reference attitude is obtained. Only, by fitting the tapered shaft part and a fitting part of the tapered hole, the reference attitude is obtained. By providing a tightening part in the jigs 6, 7, a device is applicable for a robot for by wall mounting and hanging device.

Development of a stair-climbing mobile robot with legs and wheels

Abstract: This paper deals with the development of a stair-climbing mobile robot with legs and wheels. The main technical issues in developing this type of robot are the stability and speed of the robot while climbing stairs. The robot has two wheels in the front of the body to support its weight when it moves on flat terrain, and it also has arms between the wheels to hook onto the tread of stairs. There are two pairs of legs in the rear of the body. Using not only the rorational torque of the arms and the wheels, but also the force of the legs, the robot goes up and down stairs. It measures the size of stairs when going up and down the first step, and therefore the measurement process does not cause this robot to lose any time. The computer which controls the motion of the robot needs no complicated calculations as other legged robots do. The mechanism of this robot and the control algorithm are described in this paper. This robot will be developed as a wheelchair with a stair climbing mechanism for disabled and elderly people in the near future.

An unified approach to teleoperation: human and robot integration

Abstract: To increase the accuracy and the reliability of teleoperation, close interaction between human and the slave robot is required. Korea Institute of Science and Technology (KIST) is developing a Humanoid robot, which has two 9-DOF arms, two 4-DOF hands, a 3-DOF waist and a 2-DOF neck. An automatic path planner which takes advantage of redundancy is also developed, but it requires huge computational power and time. For tasks which are very complex, or interacting with environments, robot path can be generated very easily and accurately by human teaching, hence the automatic path planner is not required. Using sensors, human motion is analyzed and converted to robot joint angles. For tasks interacting with unknown environment, teleoperation with force feedback is more useful. A simple platform-type master arm is designed based on the kinematic analysis of human. For force reflection, the pneumatic actuators are used. This device is integrated with KIST Humanoid robot as well as graphic simulator, so that the master arm can be used for teaching the robot or as the virtual reality device integrated with the graphic simulator. Force reflecting master hand is also developed. These force reflecting master arm and hand are very light and compact so that a human can wear easily while he feels the same force as the robot does while giving position command to the slave robot. In addition to master arm/hand, visual information is feedback to human through HMD for higher interaction. Therefore, a new way of integration of human and the robot is developed.

Heterogeneous function-based human/robot cooperations

Abstract: Explores a new dimension in the area of human/robot cooperation: heterogeneous human/robot cooperations. The heterogeneity of human and robot functions can be characterized by the fact that humans are intelligent while robots are fast, powerful and accurate. The important issue, in light of human/robot heterogeneity, is how to plan and control a robotic operation such that the human and the robot can cooperate in a complementary manner. In the paper, the specific problems to be discussed include developing a perceptive action reference frame to integrate human/robot heterogeneous functions; and modeling, analyzing and designing an integrated human/robot system with respect to the perceptive reference frame. These lead to the development of theoretical results on stability of human/robot cooperations, and special methods for planning and control of human/robot integrated systems. The implementations and experimental results presented demonstrate the advantages of the proposed methods.

Reactive planning of robot arms in single and cooperative tasks

Abstract: Reactive/agent based planners which have been previously applied to mobile robots with autonomous tasks are extended to fixed robot arms in an obstacle rich environment. Initial work describes how the environment is represented to provide both information to the planner and mimic potential sensor information. Basic behaviours are then derived which enable a robot to move in planar space, an outline of simple local minima avoidance methods is then given. This 2D planner is then extended to the more general classification of an industrial robot arm with 3D planning with allowance for prismatic and revolute joints. Static and moving obstacles can be handled by the planner and it is especially useful in unstructured environments and real-time situations.

Robotic assistance for aged people

Abstract: Welfare robot technology to assist aged persons is presented. The tea serving robot can carry a cup of tea according to human instructions. The suspended-from-ceiling type tea serving robot requires no installation area since the robot hand is suspended from the ceiling of a house. The standing-on-floor type tea serving robot can be easily moved due to its rod structure which is equipped with a three directional drive mechanism and a robot hand. The idea for the standing-on-floor type robot came from a drip transfusion stand in hospitals. Two types of robots which assist in walking and moving up-and-down stairs were also developed. Both types use a handrail of a house to assist aged persons. The stick type robot can assist in walking and moving up-and-down stairs using tires and rubber belts. The biped type robot can assist using a structure with two legs.

Omni-directional self-propulsive trowelling robot

Abstract: A omni-directional self-propulsive trowelling robot is proposed. The proposed robot with two rotary trowels does not require any mechanism such as wheels to obtain driving forces. When the robot flattens a concrete floor with its two rotating trowels, the unbalanced friction forces occur between the trowels and the concrete floor. These friction forces are used to move the robot. Thus, the robot can move in any direction by controlling the two rotary trowels properly. In this paper, firstly the driving force for each trowel is computed by deriving the friction force between the trowel and the concrete floor. Secondly, the relationship between the driving force for the robot and the control variable of the robot is derived. Finally, the basic motions of the robot are realized by using the obtained relationship. This paper figures out how the concrete floor finishing robot with two trowels moves and will contribute to realizing it.

A singular point avoiding method in direct teaching of articulated robot

Abstract: PROBLEM TO BE SOLVED: To provide a singular point avoiding method which requires little calculation and can be easily realized, in direct teaching when teaching a robot SOLUTION: This singular point avoiding method is for a tip of a robot arm not to pass through a singular point inherent to a robot, when carrying out direct teaching to the robot with plural joints The tip of the robot arm is arranged to damp a component of velocity, which can not be realized at the singular point by a correction formula defined in advance, as it approaches to the singular point In the correction formula defined in advance, a correction function to linearly make the component of velocity closer to zero, as the tip of the arm approaches closer to the singular point and to make it zero in the neighborhood of the singular point, is used The correction function is a function having an index variable to indicate a distance from the singular point as its variable

GripSee: A Robot for Visually-Guided Grasping

Abstract: We have designed an anthropomorphic robot system at our institute as a research platform and demonstrator for the next generation of service robots. GripSee is a visually guided robot which is endowed with a number of skills based on different neural network architectures. The skills include the interpretation of human gestures, localization and recognition of objects, planning and generation of grasping movements, and automatic calibration of the eye-hand coordination. This paper gives an overview of the system and reports on our experiences in applying diverse neural network architectures in a real robot.

Control architecture for a three-wheeled roller robot

Abstract: We present the implementation of an architecture for the distributed control of an omnidirectional mobile robot driven by stepper motors. We have developed the kinematic modelling of such a robot from which control and sensor equations are derived. These relations permit us to map in time, movements with respect to a fixed floor frame into wheels movements, and vice versa. A hierarchical control model has been selected for real time computation of control algorithm and parallel synchronisation of motors movement. It consists on a low cost specific hardware which includes one master processor (a PC) plus three slave microcontrollers (8051).

Development of a hot-line work robot, "Phase II" and a training system for robot operators

Abstract: Since 1990, Kyushu Electric Power Co. Inc. (KEPCO) has actively strived for development of a semi automatic hot-line work robot system, called Phase II. At this point, to expand automated tasks performed by the robot, we have developed a two-point laser measuring method based on measurements of the work object's position and orientation. Additionally, a simplified robot language exclusively for Phase II was developed. We have also produced a training system for robot operators. Incorporating these functions in the existing Phase II made for remarkable work efficiency with the robot. With these developments, the robot system's efficiency in terms of operation has been entirely achieved. This paper outlines these developed functions and methods.

RRR-robot : design of an industrial-like test facility for nonlinear robot control

Abstract: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication

Controller of robot for spot welding

Abstract: PROBLEM TO BE SOLVED: To give a means by which if a welding gun and the robot are synchronously moved or if they are independently moved, can be freely selected SOLUTION: In servogun robots 22, 23 (one servogun robot or over) driving weld gun tips by one articulated robot 21 and motor-driven servomechanisms 25, 26, in a synchronization OFF state, each robot is independently moved each other On the other hand, in a synchronization ON state, the respective servogun robots 22, 23 which become slaves, are moved at not a moving speed designated in each work program of the servogun robots 22, 23 but at a moving time designated by the moving time information of the articulated robot 21 which becomes a master Consequently, the synchronous control of the articulated robot 21 and the servogun robots 22, 23 becomes possible, and the changeover of the synchronous control and the independent control is freely performed in one work program

Analysis of robot motion performance and implications to economy principles

Abstract: This paper utilizes the idea of "robot ergonomics" in which robotic tasks are evaluated according to ergonomics criteria. Robot performance is continuously recorded in terms of total motion for each robotic link, the load applied on each joint, and the accuracy of each motion. Evaluating robot motion can assist in the design of a robotic cell, where robot position and layout of peripheral equipment are determined. In previous work, the main measure has been arm joint utilization (AJU). Two new measures are developed here: arm joint accuracy (AJA) and arm joint load (AJL). A test case of an articulated industrial robot, performing a kitting task is presented. Robot performance is evaluated for various bin positions, and based on these results, the bin position relative to the robot is determined based on all three measures, AJA, AJL and AJU.

Automatic blast device

Abstract: PROBLEM TO BE SOLVED: To provide a device to automatically apply blast treatment on a solid and large work, to reduce equipment cost by simplifying structure of the device, to improve blast treatment capacity, to reduce a blast treatment impossible region and to improve blast treatment quality. SOLUTION: To apply automatic blast treatment along an overall region or almost along the overall region on inner and outer surfaces of a work W by a robot 6 while making the work W self-travel on the lower side of a beam frame 4 by providing a carrier carriage 3 to self-travel in the longitudinal direction on a rail 8, the beam frame 4 fixedly provided, a robot support mechanism 5 free to laterally move in the cross direction along a beam part 4b of the beam frame 4, the articulated robot 6 installed on a horizontal arm member 15 of an L shaped arm 11 of the robot support mechanism 5 and a blast grain body supply mechanism to force-feed blast grain body with pressure air to a blast nozzle 31 installed on a hand of the articulated robot 6.

Articulated robot system with function of measuring attitude, method and system for certifying measuring precision of gyro by use of turntable for calibration reference, and device and method for calibrating turntable formed of n-axes

Abstract: PROBLEM TO BE SOLVED: To realize a real-time, non-contact, and highly precise attitude measurement free from limitation of measuring range by arranging a piezoelectric rotary gyro at the fingertip of a robot SOLUTION: An articulated robot system 100 is provided with a piezoelectric element rotary gyro 50 which consists of, for example, two gyro units each consisting of two sets of piezoelectric element-made benders and detects the angular velocity around three axes and acceleration in three axial directions of the fingertip of a robot 10 The detected angle speed is arithmetically processed by a signal processing box 55, whereby the attitude change from the initial attitude can be determined The static and dynamic precision certification with the assumption of the natural movement of the robot with respect to the gyro 50 is performed, for example, by use of a turntable with three degrees of freedom as calibration reference, and a laser tracking system, for example, is used for the calibration of dimensional error or mounting error of the turntable itself