Showing papers on "Robot kinematics published in 1994"
Book•
22 Mar 1994
TL;DR: In this paper, the authors present a detailed overview of the history of multifingered hands and dextrous manipulation, and present a mathematical model for steerable and non-driveable hands.
Abstract: INTRODUCTION: Brief History. Multifingered Hands and Dextrous Manipulation. Outline of the Book. Bibliography. RIGID BODY MOTION: Rigid Body Transformations. Rotational Motion in R3. Rigid Motion in R3. Velocity of a Rigid Body. Wrenches and Reciprocal Screws. MANIPULATOR KINEMATICS: Introduction. Forward Kinematics. Inverse Kinematics. The Manipulator Jacobian. Redundant and Parallel Manipulators. ROBOT DYNAMICS AND CONTROL: Introduction. Lagrange's Equations. Dynamics of Open-Chain Manipulators. Lyapunov Stability Theory. Position Control and Trajectory Tracking. Control of Constrained Manipulators. MULTIFINGERED HAND KINEMATICS: Introduction to Grasping. Grasp Statics. Force-Closure. Grasp Planning. Grasp Constraints. Rolling Contact Kinematics. HAND DYNAMICS AND CONTROL: Lagrange's Equations with Constraints. Robot Hand Dynamics. Redundant and Nonmanipulable Robot Systems. Kinematics and Statics of Tendon Actuation. Control of Robot Hands. NONHOLONOMIC BEHAVIOR IN ROBOTIC SYSTEMS: Introduction. Controllability and Frobenius' Theorem. Examples of Nonholonomic Systems. Structure of Nonholonomic Systems. NONHOLONOMIC MOTION PLANNING: Introduction. Steering Model Control Systems Using Sinusoids. General Methods for Steering. Dynamic Finger Repositioning. FUTURE PROSPECTS: Robots in Hazardous Environments. Medical Applications for Multifingered Hands. Robots on a Small Scale: Microrobotics. APPENDICES: Lie Groups and Robot Kinematics. A Mathematica Package for Screw Calculus. Bibliography. Index Each chapter also includes a Summary, Bibliography, and Exercises
6,592 citations
01 Aug 1994
TL;DR: A linear solution that allows a simultaneous computation of the transformations from robot world to robot base and from robot tool to robot flange coordinate frames and is noniterative, fast and robust.
Abstract: The paper presents a linear solution that allows a simultaneous computation of the transformations from robot world to robot base and from robot tool to robot flange coordinate frames. The flange frame is defined on the mounting surface of the end-effector. It is assumed that the robot geometry, i.e., the transformation from the robot base frame to the robot flange frame, is known with sufficient accuracy, and that robot end-effector poses are measured. The solution has applications to accurately locating a robot with respect to a reference frame, and a robot sensor with respect to a robot end-effector. The identification problem is cast as solving a system of homogeneous transformation equations of the form A/sub i/X=YB/sub i/,i=1, 2, ..., m. Quaternion algebra is applied to derive explicit linear solutions for X and Y provided that three robot pose measurements are available. Necessary and sufficient conditions for the uniqueness of the solution are stated. Computationally, the resulting solution algorithm is noniterative, fast and robust. >
207 citations
08 May 1994
TL;DR: This work calculates the partition of the configuration space R/sup 2//spl times/S/sup 1/ of a car-like robot, only moving forwards, with respect to the type of the length optimal paths, and gives new optimality conditions on these paths.
Abstract: We calculate the partition of the configuration space R/sup 2//spl times/S/sup 1/ of a car-like robot, only moving forwards, with respect to the type of the length optimal paths. This kind of robot is subject to kinematic constraints on its path curvature and its orientation. Starting from the results on shortest paths, we give new optimality conditions on these paths, and compute the partition for any horizontal plane of the configuration space. >
183 citations
08 May 1994
TL;DR: A numerical comparison of kinematic, dynamic and electrical parameters for the PUMA 560 robot which have been reported in the literature is presented, for the first time, data from several experiments are presented in a single system of coordinates, which facilitates comparison.
Abstract: The PUMA 560 robot is the white rat of robotics research - it has been studied and used in countless experiments over many years and in many laboratories. However, it remains a challenge to assemble the complete data needed for model-based control of the robot. This paper presents a numerical comparison of kinematic, dynamic and electrical parameters for the PUMA 560 robot which have been reported in the literature. For the first time, data from several experiments are presented in a single system of coordinates, which facilitates comparison. Differences in the data and the various methods of measurement are discussed. New data have been gathered and are presented where the record was incomplete. >
177 citations
TL;DR: It is concluded that the successful solution of the control problem has implications for biological visuo-motor control because the neural network employed in the control of the SoftArm bears close analogies to a network which successfully models visual brain maps.
Abstract: A neural map algorithm has been employed to control a five-joint pneumatic robot arm and gripper through feedback from two video cameras. The pneumatically driven robot arm (SoftArm) employed in this investigation shares essential mechanical characteristics with skeletal muscle systems. To control the position of the arm, 200 neurons formed a network representing the three-dimensional workspace embedded in a four-dimensional system of coordinates from the two cameras, and learned a three-dimensional set of pressures corresponding to the end effector positions, as well as a set of 3/spl times/4 Jacobian matrices for interpolating between these positions. The gripper orientation was achieved through adaptation of a 1/spl times/4 Jacobian matrix for a fourth joint. Because of the properties of the rubber-tube actuators of the SoftArm, the position as a function of supplied pressure is nonlinear, nonseparable, and exhibits hysteresis. Nevertheless, through the neural network learning algorithm the position could be controlled to an accuracy of about one pixel (/spl sim/3 mm) after 200 learning steps and the orientation could be controlled to two pixels after 800 learning steps. This was achieved through employment of a linear correction algorithm using the Jacobian matrices mentioned above. Applications of repeated corrections in each positioning and grasping step leads to a very robust control algorithm since the Jacobians learned by the network have to satisfy the weak requirement that the Jacobian yields a reduction of the distance between gripper and target. The neural network employed in the control of the SoftArm bears close analogies to a network which successfully models visual brain maps. It is concluded, therefore, from this fact and from the close analogy between the SoftArm and natural muscle systems that the successful solution of the control problem has implications for biological visuo-motor control. >
172 citations
12 Sep 1994
TL;DR: The author presents the robot learning problem as a lifelong problem, in which a robot faces a collection of tasks over its entire lifetime, that provides the opportunity to gather general-purpose knowledge that transfers across tasks.
Abstract: Designing robots that learn by themselves to perform complex real-world tasks is a still-open challenge for the field of robotics and artificial intelligence. In this paper the author presents the robot learning problem as a lifelong problem, in which a robot faces a collection of tasks over its entire lifetime. Such a scenario provides the opportunity to gather general-purpose knowledge that transfers across tasks. The author illustrates a particular leaning mechanism, explanation-based neural network learning, that transfers knowledge between related tasks via neural network action models. The learning approach is illustrated using a mobile robot, equipped with visual, ultrasonic and laser sensors. In less than 10 minutes operation time, the robot is able to learn to navigate to a marked target object in a natural office environment. >
152 citations
TL;DR: It is shown that the product-of-exponentials (POE) formula admits a simple global interpretation of an open kinematic chain and possesses several useful device-independent features absent in the Denavit-Hartenberg (DH) representations.
Abstract: In this article we investigate the modeling and computational aspects of the product-of-exponentials (POE) formula for robot kinematics. While its connections with Lie groups and Lie algebras give the POE equations mathematical appeal, little is known regarding its usefulness for control and other applications. We show that the POE formula admits a simple global interpretation of an open kinematic chain and possesses several useful device-independent features absent in the Denavit-Hartenberg (DH) representations. Methods for efficiently computing the forward kinematics and Jacobian using these equations are presented. In particular, the computational requirements for evaluating the Jacobian from the POE formula are compared to those of the recursive methods surveyed in Orin and Schrader (1984). >
136 citations
08 May 1994
TL;DR: A method is presented for autonomous kinematic calibration of a 3-DOF redundant parallel robot and Experimental results are presented and compared with the results using an external calibration device.
Abstract: A method is presented for autonomous kinematic calibration of a 3-DOF redundant parallel robot. Multiple closed loops are used in a least squares optimization method. Ill-conditioning, column scaling of the gradient matrix, and observability indices for the best pose set of robot calibration configurations are discussed. Experimental results are presented and compared with the results using an external calibration device. >
126 citations
08 May 1994
TL;DR: A general learning algorithm is presented for determining the mapping between robot position and object appearance, which enables accurate visual control without any prior hand-eye calibration.
Abstract: The problem of vision-based robot positioning and tracking is addressed. A general learning algorithm is presented for determining the mapping between robot position and object appearance. The robot is first moved through several displacements with respect to its desired position, and a large set of object images is acquired. This image set is compressed using principal component analysis to obtain a four-dimensional subspace. Variations in object images due to robot displacements are represented as a compact parametrized manifold in the subspace. While positioning or tracking, errors in end-effector coordinates are efficiently computed from a single brightness image using the parametric manifold representation. The learning component enables accurate visual control without any prior hand-eye calibration. Several experiments have been conducted to demonstrate the practical feasibility of the proposed positioning/tracking approach and its relevance to industrial applications. >
108 citations
TL;DR: In this article, two parameter identification methods for inertial parameters of the unknown object handled by manipulators on a free-flying space robot are proposed under the condition that the robot is free to translate and rotate.
Abstract: This paper is concerned with parameter identification methods for inertial parameters of the unknown object handled by manipulators on a free-flying space robot. The parameter identification is necessary for precise control because the payload changes the kinematics of the system together with the dynamics. Two methods are proposed under the condition that the robot is free to translate and rotate. One method is based on the conservation principle of linear and angular momentum and the other on Newton-Euler equations of motion. Only the linear/ angular velocities and accelerations of the satellite base are used in the identification methods with no information about the force and torque utilized. The feasibility of the methods is demonstrated by a hardware experiment on the ground as well as numerical simulation.
103 citations
08 May 1994
TL;DR: This nonholonomic planner employs a direct projection strategy to modify online the output of a holonomic incremental planner, and generates velocity control inputs that realize the desired motion in a least-squares sense.
Abstract: We present a simple approach for planning the motion of nonholonomic robots among obstacles. Existing methods lead to open-loop solutions which are either obtained in two stages, approximating a previously built holonomic path, or computationally intensive, being based on configuration space discretization. Our nonholonomic planner employs a direct projection strategy to modify online the output of a holonomic incremental planner, and generates velocity control inputs that realize the desired motion in a least-squares sense. As a result, a feedback scheme is obtained which can use only local sensor information. The proposed approach is applied to unicycle kinematics, with artificial potential fields or vortex fields as local holonomic planners. >
14 Dec 1994
TL;DR: The mobile robot is shown to be exponentially stabilizable for a class of quadratic Lyapunov functions and ideal tracking of the prescribed trajectories is achieved by exploiting the invariance property and the order reduction property of sliding mode control.
Abstract: Mobile robots with non-holonomic kinematics have three degrees of freedom for planar motion, but there are only two control inputs available. The stabilization problem for such robots is known not to be solvable via smooth time-invariant feedback. The authors propose to utilize a Lyapunov function to prescribe a set of desired trajectories to navigate the robot to a specified configuration. Ideal tracking of the prescribed trajectories is achieved by exploiting the invariance property and the order reduction property of sliding mode control. The mobile robot is shown to be exponentially stabilizable for a class of quadratic Lyapunov functions. >
01 Aug 1994
TL;DR: An explicit design procedure for selecting the proportional and derivative gains of the PD control with computed feedforward of robot manipulators is proposed, which assures that the closed-loop system has an unique equilibrium point.
Abstract: In the present paper, we propose an explicit design procedure for selecting the proportional and derivative gains of the PD control with computed feedforward of robot manipulators. The proposed procedure, which is easily obtained from the robot dynamics and desired trajectory, assures that the closed-loop system has an unique equilibrium point. In addition, this equilibrium turns out to be (locally) exponentially stable. Simulation tests are included, with reference to a robot having two degrees of freedom. >
12 Sep 1994
TL;DR: An efficient algorithm for localizing a mobile robot in an environment with landmarks and shows how to estimate the robot's position using a new technique that involves a complex number representation of the landmarks.
Abstract: We describe an efficient algorithm for localizing a mobile robot in an environment with landmarks. We assume that the robot has a camera and maybe other sensors that enable it to both identify landmarks and measure the angles subtended by these landmarks. We show how to estimate the robot's position using a new technique that involves a complex number representation of the landmarks. Our algorithm runs in time linear in the number of landmarks. We present results of our simulations and propose how to use our method for robot navigation. >
01 Jun 1994
TL;DR: The authors develop and analyze synchronous and asynchronous manipulation protocols for a small team of cooperating mobile robots than can push large boxes and present a methodology for creating new manipulation strategies out of existing ones.
Abstract: Donald (1993) described a manipulation task for cooperating mobile robots that can push large, heavy objects. There, the author asked whether explicit local and global communication between the agents can be removed from a family of pushing protocols. In this paper, the authors answer in the affirmative. They do so by using the general methods of Donald for analyzing information invariants. The authors discuss several measures for the information complexity of the task of pushing with cooperating mobile robots, and they present a methodology for creating new manipulation strategies out of existing ones. The authors develop and analyze synchronous and asynchronous manipulation protocols for a small team of cooperating mobile robots than can push large boxes. The protocols described have been implemented in several forms on the Cornell mobile robots in the authors' laboratory. >
TL;DR: In this article, a survey of calibration and accuracy of kinematic and dynamic models for manipulation robots is presented, where results in measurement and identification of parameters of robot mechanisms, as well as compensation of positioning errors introduced by the differences between the actual robot and the idealized (nominal) Kinematic robot model are presented.
08 May 1994
TL;DR: Simulation of a 48 struct walking robot illustrates the use of CMS joints to design more complex structures and demonstrates new algorithms for parallel robot control.
Abstract: A new spherical joint mechanism which is well suited to parallel robotics is presented. The concentric multilink spherical (CMS) joint allows two or more struts to be connected together such that they rotate about a single point. This joint can replace the traditional ball or universal (Hooke) joints in Stewart platforms, variable geometry truss manipulators, and other parallel robots. The TETRA2 robot consists of five nodes and six actuated struts. It provides a range of motion of 1m/spl times/0.5m/spl times/0.5m and has lifted a payload of 10 kg at full lateral extension. Simulation of a 48 struct walking robot illustrates the use of CMS joints to design more complex structures. The simulation also demonstrates new algorithms for parallel robot control. >
08 May 1994
TL;DR: It is shown that along with message passing, the sign-board model is one of the two important mechanisms for inter-robot communication and a simple fix exists if the propagation delay is bounded.
Abstract: Inter-robot communication based on the conceptual mechanism of "sign-board" in distributed robotic systems (DRS) is discussed. Equipped by each robot, a sign-board can be written only by the robot that carries it, and be read by robots in the neighborhood. Consistent with DRS principles, the sign-board model is not supported by any centralized mechanism, and is considered a natural way of interaction among autonomous robotic units. It is shown that along with message passing, the sign-board model is one of the two important mechanisms for inter-robot communication. Previous research on DRS algorithms employing the sign-board model assume zero signal propagation delay. These algorithms may fail if non-zero propagation delay is taken into account. A simple fix for these algorithms exists if the propagation delay is bounded. Implementation strategies for the conceptual sign-board are also discussed. >
08 May 1994
TL;DR: Methods for planning mobile robot trajectories by considering the kinematic and dynamic constraints on the vehicle motion and the resulting path is smooth and quasilinear in curvature variations are presented.
Abstract: This paper presents methods for planning mobile robot trajectories by considering the kinematic and dynamic constraints on the vehicle motion. The resulting path is smooth and quasilinear in curvature variations. The maximum value of the curvature can be assured to be smaller than the value given by the constraints. Furthermore, speeds along the path are planned subject to the kinematic and dynamic constraints. The resulting trajectories provide ideal conditions for high precision path tracking and positioning. In the paper we present the application of the proposed methods to RAM-1, a new mobile robot designed and built for indoor and outdoor industrial environment. >
TL;DR: In this article, a control methodology for catching a fast moving object with a robot manipulator, where visual information is employed to track the trajectory of the target, is described and a simple but reliable model of the robot controller has been taken into account in the control architecture for improving the performance of the system.
Abstract: A control methodology for catching a fast moving object with a robot manipulator, where visual information is employed to track the trajectory of the target, is described here. Sensing, planning, and control are performed in real time to cope with possible unpredictable trajectory changes of the moving target, and prediction techniques are adopted to compensate the time delays introduced by visual processing and by the robot controller. A simple but reliable model of the robot controller has been taken into account in the control architecture for improving the performance of the system. Experimental results have shown that the robot system is capable of tracking and catching an object moving on a plane at velocities of up to 700 mm/s and accelerations of up to 1500 mm/s/sup 2/. >
TL;DR: In this article, a simple yet accurate approach to measure the six degree of freedom position and orientation of a robot end-effector is presented. Butler et al. proposed a 3-2-1 kinematic configuration for the Stewart platform which can be used to make both static and dynamic measurements for robot calibration and real-time endpoint control.
Abstract: This paper outlines a simple yet accurate approach to measuring the six degree of freedom position and orientation of a robot end-effector. The mechanism, which will be far less costly than currently available devices, can be used to make both static and dynamic measurements for robot calibration as well as real-time endpoint control. The kinematics of the approach stem from a configuration of the Stewart platform. A “3-2-1” kinematic configuration is proposed which results in a closed-form forward kinematic solution for the Stewart platform. The closed-form algorithm can be computed about 100 times faster than conventional iterative algorithms. A prototype system using six string encoders was built and tested. Issues on error compensation were also studied. The presented approach should be useful for a broad range of applications other than robot metrology where convenient, low-cost, six degree of freedom static and/or dynamic pose measurements are required or preffered.
01 Jun 1994
TL;DR: In this chapter, the author examines the role of force and Elasticity in the kinematic design of mobile robots, as well as their role in the physical properties of the frame.
Abstract: Introduction. 1. Workspace and Trajectory Analysis. 2. Computational Geometry in Kinematics. 3. Kinematic Errors and Calibration. 4. Kinematics of Mobile Robots. 5. Kinematic Performance. 6. Kinematics in Control. 7. Force and Elasticity Analysis. 8. Inverse Kinematics. 9. Kinematic Design. 10. Kinematic Analysis. 11. Parallel Manipulators. 12. Task and Motion Planning. Author Index.
26 Jun 1994
TL;DR: The simulation results show that the proposed method, only using dynamic information acquired by ultrasonic sensors, can perform robot navigation in complex and uncertain environments by efficiently weighting reactive behaviors, such as obstacle avoidance, edge following, and moving to the target.
Abstract: This paper presents a method for fuzzy logic-based 'perception-action' behavior control of a mobile robot in uncertain environments. A key problem in 'perception-action' behavior control is to coordinate and integrate more reactive behaviors when the mobile robot executes tasks in complex environments. The main idea of the paper is to formulate 'perception-action' behaviors and to coordinate their conflicts and competitions by fuzzy sets and fuzzy rules. An advantage of this method is that the coordination of more reactive behaviors is very robust (nearly independent of dynamic environments). The simulation results show that the proposed method, only using dynamic information acquired by ultrasonic sensors, can perform robot navigation in complex and uncertain environments by efficiently weighting reactive behaviors, such as obstacle avoidance, edge following, and moving to the target. >
TL;DR: In this paper, the authors define the property of kinematic fault tolerance and develop a general constructive proof of the existence of fault tolerant manipulators, based on which a planar manipulator with a minimal kinematics structure is designed.
08 May 1994
TL;DR: A geometrical construction is provided to construct a system of two planar parallel manipulators with each 6 solutions to the forward kinematic problem and a Stewart platform with 12 configurations is exhibited.
Abstract: We consider a Stewart platform and show that its forward kinematics has at most 12 solutions. A first geometrical demonstration is provided which uses the concept of circularity and in a second proof we show that this problem is equivalent to find a system of two planar parallel manipulators with each 6 solutions to the forward kinematic problem. A geometrical construction is provided to construct such a system and a Stewart platform with 12 configurations is exhibited. >
12 Sep 1994
TL;DR: The communication and cooperation between components to achieve distributed organized control architectures is studied and the main advantage of the new control architecture is the distributed execution of tasks or subtasks by components of the multi-robot system.
Abstract: In this paper a new intelligent control architecture for autonomous multi-robot systems is presented. Furthermore, the paper deals with task description, task distribution, task allocation and coordination of the system components. The main advantage of the new control architecture is the distributed execution of tasks or subtasks by components of the multi-robot system. The components are able to build teams dynamically thereby avoiding the bottle neck problem of the information flow in centralized controlled architectures. The communication and cooperation between components to achieve distributed organized control architectures is studied. The described intelligent control architecture is to replace the former control architecture of the autonomous robot KAMRO. >
12 Sep 1994
TL;DR: A model of hand teleoperation is proposed in which the input device commands the motions of a grasped object rather than the joint displacements of the fingers to achieve greater autonomy and the capability to perform high-level functions with minimal external input.
Abstract: This paper considers adding autonomy to robot hands used in teleoperation systems. Currently, the finger positions of robot hands in teleoperation systems are controlled via a robot master using a Dataglove or exoskeleton. There are several difficulties with this approach: accurate calibration is hard to achieve; robot hands have different capabilities from human hands; and complex force reflection is difficult. In this paper we propose a model of hand teleoperation in which the input device commands the motions of a grasped object rather than the joint displacements of the fingers. To achieve this goal, the hand requires greater autonomy and the capability to perform high-level functions with minimal external input. Therefore, a set of general, primitive manipulation functions that can be performed automatically is defined. These elementary functions control simple rotations and translations of the grasped objects. They are incorporated into a teleoperation system by using a simple input device as a control signal. Preliminary implementations with a Utah/MIT are discussed. >
08 May 1994
TL;DR: A control algorithm based on Jacobian control for coordinated position and force control for autonomous multi-limbed mobile robotic systems, called coordinated Jacobian transpose control, or CJTC is proposed.
Abstract: This analytic and experimental study proposes a control algorithm based on Jacobian control for coordinated position and force control for autonomous multi-limbed mobile robotic systems. The technique is called coordinated Jacobian transpose control, or CJTC. Such position/force control algorithms will be required if future robotic systems are to operate effectively in unstructured environments. Generalized control variables, GCV's, express in a consistent and coordinated manner the desired behavior of the forces exerted by the multi-limbed robot on the environment and a system's motions. The effectiveness of this algorithm is demonstrated in simulation and laboratory experiments on a climbing system. >
08 May 1994
TL;DR: A method is presented that uses multiple demonstrations of the same task to identify a more satisfactory robot trajectory, and variation in human trajectories between trials is attributed to human inconsistency and is used to define an obstacle free region by applying the Jordan curve theorem.
Abstract: Programming by human demonstration is an intuitive method of robot programming, in which the programmer demonstrates how a task is performed using a human/robot teaching device that measures human motion, and the data gathered is used to generate the robot program. A direct duplication of the demonstrated trajectory would result in unnecessary robot motion due to human "wiggles" and unintended motion. To identify a more satisfactory robot trajectory, a method is presented that uses multiple demonstrations of the same task. Variation in human trajectories between trials is attributed to human inconsistency and is used to define an obstacle free region, by applying the Jordan curve theorem. The shortest path within the obstacle free region is determined, resulting in a shorter robot path than any of the demonstrations. Thus the presence of human inconsistency is used to improve robot performance. The analysis is restricted to planar translational motion. >
12 Sep 1994
TL;DR: This paper investigates the motion control issues involved in distributing the task of transporting an object over a group of homogeneous mobile robots to identify a method that requires minimum real-time inter-robot communication and computational effort to achieve the group goal.
Abstract: This paper investigates the motion control issues involved in distributing the task of transporting an object over a group of homogeneous mobile robots. We assume that each individual robot has no advanced sensory or communication capability. The motion control here refers to that of the robots to form some geometric pattern before they start moving and to maintain the geometric pattern while the robots are moving towards a goal location. The motion control of the robots is implemented in a distributed fashion. A distributed, concurrent algorithm for forming geometric patterns is discussed. Different control methods are presented and the simulation results from resting these methods are examined. The objective is to study the complexity of motion coordination of the robots in performing the overall task. The ultimate goal is to identify a method that requires minimum real-time inter-robot communication and computational effort to achieve the group goal. >