Showing papers on "Articulated robot published in 2000"

Autonomous multi-platform robot system

Abstract: An autonomous mobile robot system allocates mapping, localization, planning and control functions to at least one navigator robot and allocates task performance functions to one or more functional robots. The at least one navigator robot maps the work environment, localizes itself and the functional robots within the map, plans the tasks to be performed by the at least one functional robot, and controls and tracks the at least one functional robot during task performance. The at least one navigator robot performs substantially all calculations for mapping, localization, planning and control for both itself and the functional robots. In one implementation, the at least one navigator robot remains stationary while controlling and moving the at least one functional robot in order to simplify localization calculations. In one embodiment, the at least one navigator robot is equipped with sensors and sensor processing hardware required for these tasks, while the at least one functional robot is not equipped with sensors or hardware employed for these purposes.

Spherical rolling robot: a design and motion planning studies

Abstract: Describes a prototype and analytical studies of a spherical rolling robot, a new design of a nonholonomic robot system. The spherical robot is driven by two remotely controlled, internally mounted rotors that induce the ball to roll and spin on a flat surface. It is tracked on the plane by an overhead camera. A mathematical model of the robot's motion was developed using the nonholonomic constraints on its motion. For a number of simple motions, it is shown experimentally that the model agrees well with the results. Methods were developed for planning feasible, minimum time and minimum energy trajectories for the robot. These methods are illustrated both by mathematical simulation and hardware experiments.

A physical implementation of the self-reconfiguring crystalline robot

Abstract: We discuss a physical implementation of the crystalline robot system. Crystalline robots consist of modules that can aggregate together to form distributed robot systems. Crystalline modules are actuated by expanding and contracting each unit. This actuation mechanism permits automated shape metamorphosis. We describe the crystalline module concept and a physical implementation of a robot system with ten units. We describe experiments with this robot.

Representing the knowledge of a robot

Abstract: Acquiring information about its environment by sensing is a crucial ability of autonomous robots. Based on the established solution to the Frame Problem of the Fluent Calculus, we present a new, unifying formalism for representing and reasoning about sensing actions, knowledge preconditions, conditional actions, non-knowledge, and about what goals a robot can possibly achieve.

Rotary articulated robot and method of control thereof

Abstract: In a rotary articulated robot having at least a plurality of offset rotary joints in which a drive arm and driven arm are driven in rotation about an offset rotary axis inclined with respect to the arm axis, a hollow rotary shaft that is driven in rotation by a motor is arranged rotatably, being inclined, at the leading end of the arm of either the drive arm or driven arm while a rotor member to which turning effort from the hollow shaft is transmitted is fixed at the base of the other arm, said hollow rotary shaft and said rotor member constituting a high reduction ratio transmission/torque increasing mechanism. The method of control is that the operation of the joints is determined by dividing the operating region of the end effector into a plurality of blocks, the operating conditions of each joint necessary for movement to a prescribed block are converted to database form for each block, the teaching of operating points in the prescribed block region is converted to database form and a track is generated to the block of the operating region on the basis of the block region data; and when a reference point of the block is reached, the in-block operating point data is fetched.

Robotic calibration issues: accuracy, repeatability and calibration

Abstract: The groundwork for a contact calibration methodology using a touch probe is developed for an articulated robot arm. This solution is framed within current calibration and metrology issues in robotics based upon the kinematical mechanical design of a serial link manipulator. Accuracy, repeatability, and resolution are explored and a simplistic approach is taken. This exercise is intended to lay the groundwork for exploring the feasibility of integrating a commercial product such as a force sensor or touch trigger probe on the end of a robot arm. Candidate processes and/or applications are identified. Findings indicate that an in- process contact calibration methodology that is accurate, repeatable, and cost effective would be a desirable solution.

In-pipe inspection robot system with active steering mechanism

Abstract: We present a robot system for in-pipe inspection of underground urban gas pipelines. The robot is configured as an articulated structure like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, and passive modules such as a control module are chained between the active vehicles. The proposed robot has outstanding mobility offered by a new steering mechanism, called double active universal joint, which makes it possible to cope with complicated configurations of underground pipelines. Characteristic features of the system are described and the construction of the system is briefly outlined.

Locomotion control of a snake-like robot based on dynamic manipulability

Abstract: We discuss autonomous locomotion control of a snake-like articulated robot with passive wheels. Such a robot has a quite different mechanism in locomotion from that of other locomotion systems, namely, it has no driving wheel and moves only by bending its body. Hence the locomotability depends on its posture. In order to evaluate the locomotability, we utilize a notion of dynamic manipulability which has been applied to a robot manipulator. We also propose a simple controller based on this manipulability. Simulation results show that a certain periodic winding motion is automatically generated.

The Inchworm Robot: A Multi-Functional System

Abstract: We wish for robots to manipulate objects and move flexibly in three-dimensional spaces. We describe a robot that can move on a web of surfaces oriented around arbitrary directions in three-space and a set of control algorithms that implements motion in three-dimensions. The robot can manipulate objects in three dimensions while moving, by using the same set of physical resources and control algorithms. This robot is an inchworm-like robot with a simple, modular, and flexible design. Finally, we discuss our experiments.

A robot snake to inspect broken buildings

Abstract: We build a snake-like robot for the inspection of areas that are difficult or dangerous to be accessed by human. Pictures from a camera at the robot's head are sent to a remote screen and can be monitored by a human operator. This human operator can also control the robot's motion, but not every single body part. Thus the operator only gives general directives and the robot will then able to follow autonomously the given directives. This is the semi-autonomous behavior of the robot. However, the robot must also be able to act fully autonomous when the contact to the operator is lost. After a short description of the robot we present a method which makes the operator control easy and also allows the robot to act fully autonomous. The autonomous motion control of the robot moving in a sewer pipe has been implemented.

The anthropomorphic biped robot BIP2000

Abstract: This paper describes the progress of the BIP2000 project. This project is aimed at the realization of the lower part of an anthropomorphic biped robot. The robot consists of two legs, two feet, a pelvis and a trunk. It has 15 active joints. The mass distribution, the kinematics and the capacities of the robot in terms of joint torques are close to the ones of humans. The transmissions are specific screw/nut-based systems which have good dynamic performances and small size. They are arranged in parallel at the ankles and at the trunk/pelvis linkage. The control schemes are either based on a control of the center of mass associated with suitable task functions, or take dynamically into account the unilateral constraints foot/ground. The robot has been built and tested, the computer control architecture has been realized and connected with the robot, and the basic control schemes have been implemented.

Autonomous mobile robot in pipe for piping operations

Abstract: An autonomous mobile robot that can move autonomously in a horizontal pipe, a vertical pipe and an elbow joint with bending angle of 90/spl deg/. Furthermore, the robot has a vision sensor and an operating arm in front of the robot body, and accordingly it has functions to execute piping operations, such as inspection of pipe surface, welding of the pipes and so on. The robot is constructed by several units with four wheels connected by universal joints each other. The robot is controlled by a host personal computer and one-chip microcomputers. As the results of operating experiments, the effectiveness of the robot system in autonomous movement in a pipe and an elbow joint and automatic tracking of a welding line was confirmed.

The autonomous miniature robot Alice: from prototypes to applications

Abstract: We present an overview of the prototype family of Alice miniature mobile robots and the improvements achieved so far. Applications are often the final objective but also an incentive to correct and enhance the robot abilities. The research carried out with Alice and various real-world applications, which exceed the robot's use as a research prototype, is presented. They include local and global localization, map building, control strategies for semi-autonomous operation via Internet and Matlab, its use for robot soccer tournaments and as a research platform for studies of collective behaviors.

Sensor-based probabilistic roadmaps: experiments with an eye-in-hand system

Abstract: We present a real implemented eye-in-hand test-bed system for sensor-based collision-free motion planning for articulated robot arms. The system consists of a PUMA 560 with a triangulation-based ar...

Subsumption architecture for the control of robots

Abstract: This paper describes ongoing investigations into the subsumption control of robots. Subsumption architectures are a relatively new and simple approach to the control of robot systems. The technique has been applied to the control of experimental mobile robots. Some of the potential benefits of subsumption control over classical robot control techniques may prove useful in the context of industrial robotics. With subsumption control the robot is not controlled by a powerful reasoning system, but rather by a set of simple processes. Each of these processes is designed to provide the robot with a simple competence, for example, the ability to move away from an obstacle, to move around an area in a random fashion, or to explore the robot's environment. The processes compete for control of the robot at any given time, according to a varying priority scheme which is mediated, inter alia, by external sensor input. The subsumption approach to robot control represents an interesting alternative to classical artificial intelligence techniques, but remains unproven at this time. A small mobile robot testbed has been built to investigate the feasibility of subsumption control for robots. Three simple robot processes have been developed. These are a random motion ability, a collision avoidance competence and a light seeking/ following ability. Implementing primitive abilities such as a wandering behaviour and collision avoidance on both mobile robots and robot arms has potential applications in industrial robotics. Using a subsumption architecture could allow supervisory control to simply deal with task oriented decision making leaving lower level reaction to unexpected or uncontrolled environment conditions to lower level subsumption abilities.

Vision-based self-localization for soccer robots

Abstract: In this paper, a method for robot self-localization based on a catadioptric omni-directional sensor is introduced. The method uses natural geometric landmarks of the environment. It is assumed that the robot moves on flat surfaces and straight lines can be identified in the surrounding environment image acquired by the catadioptric system. This omni-directional vision system is based on a camera plus a convex mirror designed to obtain (by hardware) the ground plane bird's eye view. Results from the application to a real robot moving on RoboCup soccer field and concerning the method's accuracy are presented.

An industrial application of control of dynamic behavior of robots-a walk-through programmed welding robot

Abstract: Robot programming is a very tedious task that involves defining the relevant robot positions and configurations, and writing the robot program to execute the task. In this paper, we present an application of the control of the dynamic behavior of robotic manipulators to achieve walk-through programming of a powered arm. The algorithm is based on impedance control with zero stiffness to allow the robot to be moved by the human hand during walk-through teaching. We demonstrate the application using a welding robot we have customized and improved on for use in shipyards. We describe the architecture, our methodologies, the practical issues and present the results of our performance evaluation.

Development and control of new legged robot QUARTET III - from active walking to passive walking

Abstract: We introduce a newly developed legged robot QUARTET III. Two direct drive motors are mounted on the robot as a main actuator. Therefore, this robot can walk both actively and passively. We also propose a new control law for the robot on a slight slope. The strategy of the control scheme is as follows. At the beginning of the walking, the robot walks with actuator. Then after a while the control input gradually decrease. Finally, the robot walks passively. The effectiveness of the control law is shown through simulations and experiments.

Development of the quadruped walking robot, "TITAN-IX"

Abstract: This paper proposes a quadruped-walking robot that performs the humanitarian mine detection and removal tasks. We (1998) have proposed the concept of humanitarian demining robot system. We performed the basic experiments on the first prototype VK-I using the modified quadruped walking robot, TITAN-VIII. After these experiments, we refined our concept. The new robot has a tool (end-effector) changing system on its back, so by utilizing the legs as manipulation arms and connecting various tools to the foot, it can perform mine detection and removal tasks. To accomplish these tasks, we developed the various end effectors that can be attached to the working leg. In this paper we discuss the advance of the study of the robot system VK-II and introduce the new walking robot called TITAN-IX to be applied to the new VK-II. robot system.

Legged mobile robot and external module for the robot

Abstract: A legged mobile robot in which sensors which can measure contact pressure are provided so as to be distributed at corresponding portions of whole body of the robot in order to determine the state of contact with the external world. In addition, modules which use shock-absorbing members for reducing shock are provided at the corresponding portions of the whole body of the robot. These modules cover their corresponding portions of the robot in order to further function as external parts for protecting the robot from shock. The modules can be constructed so as to be removable from the body of the robot, and may include batteries for supplying electrical power to terminal parts such as sensors. The invention provides a robot which can operate while being subjected to external forces as a result of coming into contact with an obstacle or other external objects, and which makes it possible to reduce shock which is produced when the robot comes into contact with an external object.

Mixed camera-laser based control for mobile robot navigation

Abstract: Presents two control strategies based on the data provided by a camera and a 2D laser range sensor for driving a mobile robot towards a target amidst obstacles. The methods are based on the task function formalism and use the robot redundancy with respect to the tracking task to control both the base and the camera during the avoidance phase. Simulation results are given at the end of the paper.

Robot mechanisms

Abstract: Classes of robot mechanisms are reviewed. Technology constraints on robot mechanism design are discussed and examples of various robot mechanisms are provided.

Experimental identification of robot dynamics for control

Abstract: The paper discusses the experimental identification of dynamic robot models for their application in model based robot control, e.g., computed torque control. The accuracy of these controllers relies highly on the ability of the robot model to accurately predict the required actuator torques. The paper shows how this application reflects on the choices that have to be made in the different steps of the identification procedure, and consequently on the accuracy of the obtained model parameters and actuator torque prediction.

Molding apparatus and method using a robot to introduce and insert into a mold

Abstract: Apparatus for molding articles from moldable material in a mold includes end of arm tooling for an articulated robot arm associated with the mold, where the end of arm tooling includes an insert transfer member mounted on the end of the articulated robot arm. The insert transfer member has an insert holder for gripping the insert. The apparatus also includes a charger for generating an electric field that causes the insert to adhere onto a surface of the mold.

An off-line automatic teaching by vision information for robotic assembly task

Abstract: In this study, an off-line automatic teaching method using vision information for robotic assembly task is proposed Many of industrial robots are still taught and programmed by a teaching pendant. This conventional teaching method is time-consuming and somewhat dangerous. In the proposed method, the operator teaches the desired locations on the image acquired through CCD camera mounted on the robot hand The robotic language program is automatically generated and transferred to the robot controller. This teaching process is implemented through an off-line programming (OLP) software. The OLP is developed for the robotic assembly system used in this study. In order to transform the location on image coordinates into robot coordinates, a calibration process is established The proposed teaching method is implemented and evaluated on the assembly system for soldering electronic parts on a circuit board A six-axis articulated robot executes assembly task according to the off-line automatic teaching.

Interception of a projectile using a human vision-based strategy

Abstract: Visual-servoing tasks for mobile robots characteristically require the processing of vast amounts of navigational information which can impede the performance of even the most well designed systems. This paper investigates the idea of using a simple human-based strategy to guide a mobile robot to intercept a projectile. This vision based control strategy relies on a single image-based parameter whose sign corresponds to a decision whether to run forward or backward for successful interception. Assuming the ball can be tracked easily in real time by the robot's vision system, motion decision making and control computations are minimized. We examine and develop several motion control strategies which incorporate the robot's velocity and acceleration in addition to this human-based strategy. The simplest strategy is tested on a mobile robot and demonstrates results similar to a human.

Hand-Shaped Force Interface for Human-Cooperative Mobile Robot

Abstract: Aiming at realization of direct and intuitive cooperation between human and robot, we develop an interface system for a mobile robot that can take physical communication with its user via hand-to-hand force interaction The hand-shaped device equipped on the robot with a flexible rubber-made arm can sense the intentional force exerted by its user The finger part can be actuated in 1 DOF to achieve haptic force feedback The robot also has bumper sensors and ultrasonic sensors around the body The balance of the intentional force and the environmental condition determines the robot's motion In this research, we design simple algorithms for both human-following and humanleading motions, and devise experiments with human users Qualitative and quantitative evaluations of the experimental results are also presented

Master-Slave Control for Tele-Operation Construction Robot System.

Abstract: In this study, we have developed a bilateral telerobotics system for construction robot using virtual reality. The system consists of a servo-controlled construction robot, two joysticks for operation of the robot from a remote place and a 3-degrees-of-freedom motion base. The operator of the robot is sitting on the motion base and is able to control bilaterally from a remote place. The role of the motion base is to simulate the realistic motion of the construction robot. We proposed, in this study, a new method of master-slave control in order to control hydraulic actuators, which were used for actuating the construction robot. The availability of the proposed method was examined by experiment and simulation and thus the validity of the method was confirmed.

Robot control system for safe and rapid programming of grinding applications

Abstract: Presents a robot control system dedicated for grinding and deburring robots. The control system is based on an active force feedback system using three axes force sensor attached to the robot’s end effector. This system offers new functionality in rapid programming of the robot by applying automatic programming and force supervision. The system is implemented and tested experimentally on a MultiCraft 560 robot with parallel kinematics. The experimental results show a significant reduction in the programming and set up time compared to conventional robot control systems.

On-Line Evolution of Control for a Four-Legged Robot Using Genetic Programming

Abstract: We evolve a robotic controller for a four-legged real robot enabling it to walk dynamically. Evolution is performed on-line by a linear machine code GP system. The robot has eight degrees of freedom and is built from standard R/C servos. Different walking strategies are shown by the robot during evolution and the evolving system is robust against mechanical failures.