Showing papers on "Articulated robot published in 2010"

Synthesizing Robot Motions Adapted to Human Presence A Planning and Control Framework for Safe and Socially Acceptable Robot Motions

Abstract: With robotics hardware becoming more and more safe and compliant, robots are not far from entering our homes. The robot, that will share the same environment with humans, will be expected to consider the geometry of the interaction and to perform intelligent space sharing.

Real-time path planning for a robot arm in changing environments

Abstract: We present a practical strategy for real-time path planning for articulated robot arms in changing environments by integrating PRM for Changing Environments with 3D sensor data. Our implementation on Care-O-Bot 3 identifies bottlenecks in the algorithm and introduces new methods that solve the overall task of detecting obstacles and planning a path around them in under 100 ms. A fast planner is necessary to enable the robot to react to quickly changing human environments. We have tested our implementation in real-world experiments where a human subject enters the manipulation area, is detected and safely avoided by the robot. This capability is critical for future applications in automation and service robotics where humans will work closely with robots to jointly perform tasks.

Comparing ability to complete simple tele-operated rescue or maintenance mobile-robot tasks with and without a sensor system

Abstract: Purpose – The purpose of this paper is to investigate the effect on completion of mobile‐robot tasks depending on how a human tele‐operator interacts with a sensor system and a mobile‐robot.Design/methodology/approach – Interaction is investigated using two mobile‐robot systems, three different ways of interacting with the robots and several different environments of increasing complexity. In each case, the operation is investigated with and without sensor systems to assist an operator to move a robot through narrower and narrower gaps and in completing progressively more complicated driving tasks. Tele‐operators used a joystick and either watched the robot while operating it, or sat at a computer and viewed scenes remotely on a screen. Cameras are either mounted on the robot to view the space ahead of the robot or mounted remotely so that they viewed both the environment and robot. Every test is compared with sensor systems engaged and with them disconnected.Findings – A main conclusion is that human tel...

Wheel-Based Climbing Robot : Modeling and Control

Abstract: This paper addresses the kinematics modeling and control of a novel nonholonomic wheel-based pole climbing robot called UT-PCR. This robot belongs to a challenging and less-studied class of wheel-based mobile robots in which the relative position of the wheels changes in a complex manner and the robot is constrained to maneuver on a closed geometric surface. The problem is formulated in terms of the kinematic model of the robot, which is derived using non-holonomic constraints imposed by the wheels on the motion. This model is an underactuated driftless nonlinear state space (control system) which is linear in its inputs. Feasibility of complex maneuvering is then proved by an analysis of controllability for this nonlinear system. It is shown that three orientations of the robot cannot be controlled independently. Therefore, three basic movements are introduced as the fundamental elements of the kinematic control strategy and stable controllers are designed to create those basic movements. Simulation and ...

System and method for automatic calibration of stereo images

Abstract: A method and system to enable a computer to estimate calibration parameters autonomously so that accurate stereopsis can be performed. The present invention automatically calibrates two or more cameras with unknown parameters with respect to a robot or robotic appendage (e.g., articulated robot arm) with a light source that can be turned on and off at one end. A pair of cameras (e.g., digital cameras) are positioned and aimed so as to give stereoptic coverage of the robot's workspace. The procedure determines the positions and orientations of the pair of cameras with respect to a robot (i.e., exterior orientations) and the focal lengths, optical centers, and distortion coefficients of each camera (i.e., intrinsic parameters) automatically from a set of known positions of the robot arm, and a set of images from the right and left cameras of the robot arm in each position as the light is turned on and off.

Robot workspace estimation and base placement optimisation techniques for the conversion of conventional work cells into autonomous flexible manufacturing systems

Abstract: Robot arms are used in modern work cells and flexible manufacturing systems (FMS) in handling work pieces and loading/unloading processes. The robot arm links may interfere with the bodies of the system components, which are considered as obstacles in the robot workspace. In order that the robot works in safe conditions, study of robot workspace in a free space and in the presence of obstacles should be investigated. The inverse problem of having an existing working space occupied with a number of CNC machines to which it is supposed to introduce a robot to serve is an interesting problem. This is a very common problem when trying to convert conventional work cells into autonomous systems. There are two main questions when studying this kind of problem: what type of robots is suitable to satisfy the existing working space? And where to place the base of this robot to efficiently serve the existing machines? The main objective of this article is trying to answer these two questions. A computational algorithm is developed to estimate the robot workspace. The optimisation of robot base placement is achieved using genetic algorithms. A comparative study of the suitability of different robots for a specified working area is also included. Finally, robot movement visualisation within a pre-defined FMS using solid edge modelling is presented to verify the proposed algorithm and simulate the robot path within the work cell.

Industrial robot and human operator collision

Abstract: Our work is focused on cooperation of a small industrial robot and human operator where collision is expected only between the robot end-effector and the lower arm of the human worker. To study the effect of the impact between the robot and man, a passive mechanical lower arm (PMLA) was developed. The investigation presented in this paper evaluates whether the PMLA is a sufficiently accurate emulation system of a passive human lower arm. The same experiments were performed with the PMLA and with human volunteers. The results of both investigations were compared and evaluated to determine whether the PMLA can competently replace human volunteers in dangerous future investigations.

Follow-the-Contact-Point gait control of centipede-like multi-legged robot to navigate and walk on uneven terrain

Abstract: This paper proposes a novel locomotion control scheme of centipede-like multi-legged robot, which is called Follow-the-Contact-Point (FCP) gait control. A centipede-like multi-legged robot is composed of segmented trunks which have a pair of legs and are connected with fore and/or rear ones by joints. This control scheme realizes locomotion control of multi-legged robot on uneven terrain with perfectly decentralized manner. The main concept of the control scheme is to relay the contact points from the fore leg to the rear leg. By creating contact points of the first legs adequately on the environment, the robot can climb over obstacles and be navigated successfully. Finally, the result of physical simulation of a 20-legged robot shows the availability of the proposed method.

Robot system for restaurant serving

Abstract: PURPOSE: A robot system for serving in a restaurant is provided to enable the angle of a display screen to be adjusted according to a user's height. CONSTITUTION: A robot system for serving in a restaurant comprises a top portion(1000), a bottom portion(2000), and a middle portion(3000). The middle portion is fixed to the bottom portion and is rotatably connected to the top portion. A connected PCB(Printed Circuit Board) is located on the middle portion. Signal cables are connected to both sides of the connected PCB. One signal cable is connected to the top portion and the other cable is connected to the bottom portion. The top portion comprises an ordering device(1100), a camera, and a pair of articulated robot arms(1300). An oderer selects and inputs the menu through the ordering device. The bottom portion comprises a controller, a serving robot moving unit, and an obstacle detecting sensor. The controller provides the menu using the video signals of the camera. The serving robot moving unit transfers the serving robot controller according to the control of the controller.

Design, Modeling and Control of a Biped Line-Walking Robot

Abstract: The subject of this paper is the design and analysis of a biped line walking robot for inspection of power transmission lines. With a novel mechanism the centroid of the robot can be concentrated on the axis of hip joint to minimize the drive torque of the hip joint. The mechanical structure of the robot is discussed, as well as forward kinematics. Dynamic model is established in this paper to analyze the inverse kinematics for motion planning. The line-walking cycle of the line-walking robot is composed of a single-support phase and a double-support phase. Locomotion of the line-walking robot is discussed in details and the obstacle-navigation process is planed according to the structure of power transmission line. To fulfill the demands of line-walking, a control system and trajectories generation method are designed for the prototype of the line-walking robot. The feasibility of this concept is then confirmed by performing experiments with a simulated line environment.

Single wheel robot system and its control method

Abstract: This invention relates to a single wheel robot system and its control method. The robot is an intelligent self-control and thus self-balancing unicycle riding robot. The control method is the balance control method of the static imbalance unicycle robot. The single wheel robot includes mechanical body and control system; the body contains a single wheel in the substructure which can rotate around for balance; the control system comprises state sensors, motion controller, servo-driven controllers, and a power system. Among them, the motion controller receive signals from the state sensors, in accordance with control procedures for processing of the received signal, thereby issuing control instructions. The servo drive controller receives the control instructions and controls the motors of the robot to adjust posture to be balanced.

Development of a snake robot moving in a small diameter pipe

Abstract: This paper presents a snake robot moving in a small diameter pipe. A snake robot is a multi-linked modular robot. The snake robot, KAEROT-snake IV consists of 11 2-DOF actuator modules, a head, and a tail module. Each of the 2-DOF actuator modules has two small DC motors and worm gear boxes to increase the torque output and an embedded motor controller. The snake robot can move in a small diameter pipe with a sequence of holding motion as well as with a sinusoidal motion. Some modules holds the robot itself by pressing outward to induce friction while the other modules move forward/backward and hold the robot at a more front/rear position. A sequence of holding moves the robot forward/backward in a small diameter pipe.

A wall climbing robot for tank inspection. An autonomous prototype

Abstract: This paper describes a solution to a mobile climbing robot on magnetic wheels, designed for inspecting exterior oil tank surfaces made of metal sheets. A mechanical design has been developed which presents a practical solution without an umbilical cord. The inspection system has been developed based on client/server architecture. The robot runs a client application and a remote PC executes the server functions. They will both allow any necessary inspections to be performed simultaneously by more than one robot. A sensorial system and a data fusion strategy to estimate the absolute robot position is proposed to allow the robot to navigate autonomously. The graphical monitoring of the robot position in the remote PC (server application) provides the operator with the possibility of controlling the robot, even in situations in which the operator visibility of an area tank is very low or inexistent. Previous experiments have demonstrated the mechanical system's robustness. These experiments consist of robot trajectory measurements and the comparison to a motion kinematic model.

A Novel 5 DOF Fully Parallel Robot Combining 3T1R Motion and Grasping

Abstract: This paper presents an innovative 5 DOF robot that generates 3T1R motion (3 translations + 1 rotation) plus a linear grasping motion. To generate this type of grasping motion, a robot needs two end-effectors. Grasping motions are usually generated by adding a grasping device at the top of an already existing robot or by coordinating two distinct robots. We propose in this paper a new robot architecture which includes the grasping degree of freedom as a part of the mechanism itself. The two end-effectors of the mechanism are mounted on an articulated platform and can move together in a 3T1R motion and their distance to each other can be controlled to generate the grasping capability. The 5 actuators are located on the base and are connected with five identical legs to the two end-effectors using only mechanical links, forming a fully parallel robot with 5 DOF. The architecture of the robot will be presented in detail. Then, we will describe the kinematics needed for the control of the robot. Finally, geometric optimization results will be presented and discussed.© 2010 ASME

Optimization of a 4 dof tele-echography robot

Abstract: This paper deals with the optimization of the design of a 4 degree-of-freedom robot dedicated to tele-echography. It has been designed to reproduce in real time on a patient, the medical gestures performed by a remote expert moving a fictive probe. Our goal is to optimize the kinematic structure to determine geometrical parameters, as they have a significant role in the singularities localization. In this paper, we propose optimum solutions obtained from a combination of kinematic performances and compactness indices.

Haptic-based interactive path planning for a virtual robot arm

Abstract: In this paper, based on the structural similarity between the PHANToM haptic device and a six-DOF (Degrees of Freedom) articulated robot arm, a six-DOF virtual robot arm driven by the PHANToM device is modeled. In order to enable the virtual robot arm to haptically interact with virtual prototypes in a virtual assembly (VA) environment, a workspace mapping method based on robot kinematics analysis is proposed. The haptic-based virtual robot arm is used in interactive modeling in free path planning and constraint-based assembly path planning operations in the VA system. In both planning processes, the user can interactively edit an assembly path with the guiding forces as feedback. Lastly, A few experiments have been conducted to verify the effectiveness of the proposed methods. The haptic-based virtual robot arm presented in this paper provides a new human-computer interaction method for a VA system.

Design and analysis of a kind of biomimetic continuum robot

Abstract: Continuum robot is a new kind of bionic robot, and it is the beneficial supplement to the traditional joint-type robot. This paper presented a design scheme of Hook Joint type continuum robot, and fully discussed its structure and mechanism connection mode. An exponential product based matrix transformation is used to describe the position and orientation of the end-effector. The forward kinematics is also discussed in this paper. Numerical examples are completed with Matlab M language and simulation results indicate the validity of the proposed analysis method.

Trajectory planning of a one-legged robot performing stable hop

Abstract: In this paper, stable hopping of a one-legged, articulated robot with a flat foot is investigated. The robot has a special feature that before taking off, it goes through an underactuated phase in which the foot rotates about the unactuated toe on the ground. By having the underactuated phase, the robot can perform stable human-like hops with longer hopping distances. To devise a systematic trajectory design methodology for the robot, its dynamics including the ground-foot impact and the hopping constraints are carefully studied. An optimization procedure is then proposed to plan the feasible actuated trajectories which not only meet specific performance requirements but also attain certain optimality with respect to actuation energy. The hopping strategy and the optimal trajectories are verified by simulations and hardware implementation. Experiments indicate that the robot not only can stably perform hops with different hopping distances on the level ground but also can successfully hop up/down staircases.

Biologically Inspired Control of a Compliant Anthropomimetic Robot

Abstract: Anthropomimetics copying nature in order to construct and control similar mechanism in technical world is an increasingly attractive research topic. Its core objective is achieving human efficiency in the aspects of technical world where engineering still cannot compete biology (diversity of motions, manoeuvrability, etc). This paper attempts to develop the appropriate dynamic model and design control for an anthropomimetic humanoid ECCEROBOT. Robot has a human-like mechanical structure skeleton. To mimic muscles, robot joints are driven by antagonistically coupled DC motors with tendons. Since the robot is expected to work in a human centered environment and in the presence of humans, an important accent is given to the safe interaction with the surrounding. To resolve the safety, robot involves passive mechanical compliance elastic springs in tendons. The paper derives the mathematical model of robot dynamics, designed for simulation. The control of antagonistic drives is based on a biologically inspired puller-and follower concept where the puller is responsible for joint motion while the follower keeps the inactive tendon from slackening. The advanced theory of nonlinear control was used for particular joints and the theory of robustness was necessary for applying the control to multi-joint robot body.

MagneBike: Compact magnetic wheeled robot for power plant inspection

Abstract: The MagneBike robot is a magnetic wheeled robot designed for the inspection of ferromagnetic structures in power plants, especially steam chests. This video first presents the robot's locomotion concept, i.e. two aligned magnetic wheels integrating lateral lever arms, that allow the robot to pass over complex combinations of obstacles. Laboratory and field experiments show the high mobility of the robot. This video also describes the localization and mapping strategy that consists in combining 3D odometry with 3D scanning and scan registration. An animation of the 3D reconstruction of the environment shows that the localization procedure allows to provide the necessary 3D visual feedback for the remote user or for inspection mission planning.

Robot controller, robot control method, and legged robot

Abstract: A robot controller in accordance with the present invention is a robot controller that makes a robot including a plurality of legs walk by driving joints of the robot, the robot controller being configured to determine a permissible range for a trunk vertical position of the robot based on measured environmental parameters, the measured environmental parameters being information of an environment around the robot, and to make the robot walk based on measured posture parameters representing a posture of the robot so that the trunk vertical position remains within the permissible range. In this way, a legged robot with high robustness as well as its controller and control method can be provided.

Semi-active compliant robot enabling collision safety for human robot interaction

Abstract: Human robot interaction (HRI) tasks requires robots to have safe sharing of work space and to demonstrate adaptable compliant behavior enabling eminent collision safety as well as maintaining high position accuracy. Robot compliance control normally can be achieved by using active compliance control of actuators based on various sensor data. Alternatively, passive devices allow controllable compliance motion but usually are mechanically complex. We proposed a unique method using semi-active compliant actuation mechanism having magneto-rheological (MR) fluid based actutaor that introduces reconfigurable compliance characteristics into the robot joints. This enables high intrinsic safety coming from fluid mechanics as well as, it offers simpler interaction control strategy compared to other concurrent approaches. In this studies, we have described three essential modes of motions required for physical human system interaction. Furthermore, we have demonstarted robot collision safety in terms of static collision and experimentally validates the performance of robot manipulator enabling safe human robot interaction.

Hiding robot inertia using resonance

Abstract: To enable compliant training modes with a rehabilitation robot, an important prerequisite is that any undesired human-robot interaction forces caused by robot dynamics must be avoided, either by an appropriate mechanical design or by compensating control strategies. Our recently proposed control scheme of “Generalized Elasticities” employs potential fields to compensate for robot dynamics, including inertia, beyond what can be done using closed-loop force control. In this paper, we give a simple mechanical equivalent using the example of the gait rehabilitation robot Lokomat. The robot consists of an exoskeleton that is attached to a frame around the patient's pelvis. This frame is suspended by a springloaded parallelogram structure. The mechanism allows vertical displacement while providing almost constant robot gravity compensation. However, inertia of the device when the patient's pelvis moves up and down remains a source of large interaction forces, which are reflected in increased ground reaction forces. Here, we investigate an alternative suspension: To hide not only gravity, but also robot inertia during vertical pelvis motion, we suspend the robot frame by a stiff linear spring that allows the robot to oscillate vertically at an eigenfrequency close to the natural gait frequency. This mechanism reduces human-robot interaction forces, which is demonstrated in pilot experimental results.

Work-assisting robot system

Abstract: The working support robot system of the present invention includes: a robot arm (11); a measuring unit (12) for measuring the worker's position; a work progress estimation unit (13) for estimating the work progress based on data input from the measuring unit (12) while referring to data on work procedure, and for selecting objects necessary for the next task when the work is found to have advanced to the next procedure; and an arm motion planning unit (14) for planning the trajectory of the robot arm (11) to control the robot arm (11) based on the work progress estimated by the work progress estimation unit (13) and selected objects. The working support robot system can deliver objects such as tools and parts to the worker according to the work to be performed by the worker.

Design and Control of a Multi-jointed Robot Finger Driven by an Artificial Muscle Actuator

Abstract: In this paper, we present a robotic actuation system using an artificial muscle actuator based on a dielectric elastomer. A novel linear actuator called a 'multi-stacked actuator' is proposed that can be embedded in the phalanges of a multi-jointed robot finger. This actuator ensures a compact design of the overall system. As an example, a 2-d.o.f. robot finger is developed and its performance under the proposed actuator system is experimentally demonstrated. The application of the proposed system can be extended easily to a multifingered robot hand and even to articulated mechanisms such as legged robots, etc.

Robot walking control apparatus and method thereof

Abstract: Disclosed are a robot walking control apparatus, which removes an ineffective motion, generated by a robot walking based on torque, by selecting a motion state of the robot based on torque and controlling torques of joints of the robot so that a ZMP of the robot is located in a safety area, when the walking of the robot is controlled, and a method thereof.