Showing papers on "Articulated robot published in 2007"

Human-Robot Interaction for Cooperative Manipulation: Handing Objects to One Another

Abstract: For manipulation tasks, the transfer of objects between humans and robots is a fundamental way to coordinate activity and cooperatively perform useful work. Within this paper we demonstrate that robots and people can effectively and intuitively work together by directly handing objects to one another. First, we present experimental results that demonstrate that subjects without explicit instructions or robotics expertise can successfully hand objects to a robot and take objects from a robot in response to reaching gestures. Moreover, when handing an object to the robot, subjects control the object's position and orientation to match the configuration of the robot's hand, thereby simplifying robotic grasping and offering opportunities to simplify the manipulation task. Second, we present a robotic application that relies on this form of human-robot interaction. This application enables a humanoid robot to help a user place objects on a shelf, perform bimanual insertion tasks, and hold a box within which the user can place objects. By handing appropriate objects to the robot, the human directly and intuitively controls the robot. Through this interaction, the human and robot complement one another's abilities and work together to achieve results.

Task constrained motion planning in robot joint space

Abstract: We explore global randomized joint space path planning for articulated robots that are subject to task space constraints. This paper describes a representation of constrained motion for joint space planners and develops two simple and efficient methods for constrained sampling of joint configurations: Tangent Space Sampling (TS) and First-Order Retraction (FR). Constrained joint space planning is important for many real world problems involving redundant manipulators. On the one hand, tasks are designated in work space coordinates: rotating doors about fixed axes, sliding drawers along fixed trajectories or holding objects level during transport. On the other, joint space planning gives alternative paths that use redundant degrees of freedom to avoid obstacles or satisfy additional goals while performing a task. In simulation, we demonstrate that our methods are faster and significantly more invariant to problem/algorithm parameters than existing techniques.

Pre-collision safety strategies for human-robot interaction

Abstract: Safe planning and control is essential to bringing human-robot interaction into common experience. This paper presents an integrated human?robot interaction strategy that ensures the safety of the human participant through a coordinated suite of safety strategies that are selected and implemented to anticipate and respond to varying time horizons for potential hazards and varying expected levels of interaction with the user. The proposed planning and control strategies are based on explicit measures of danger during interaction. The level of danger is estimated based on factors influencing the impact force during a human-robot collision, such as the effective robot inertia, the relative velocity and the distance between the robot and the human. A second key requirement for improving safety is the ability of the robot to perceive its environment, and more specifically, human behavior and reaction to robot movements. This paper also proposes and demonstrates the use of human monitoring information based on vision and physiological sensors to further improve the safety of the human robot interaction. A methodology for integrating sensor-based information about the user's position and physiological reaction to the robot into medium and short-term safety strategies is presented. This methodology is verified through a series of experimental test cases where a human and an articulated robot respond to each other based on the human's physical and physiological behavior.

Physiological and subjective responses to articulated robot motion

Abstract: This paper describes the implementation and validation of a fuzzy inference engine for estimating human affective state in real-time, using robot motions as the stimulus. The inference engine was tested with 36 subjects. To the authors' knowledge, this paper reports the first such trial that measures affective response to human-scale physical robot motions for a statistically significant population. The results demonstrate that affective state arousal can be detected using physiological signals and the inference engine. Comparison of results between the two planners shows that subjects report less anxiety and surprise with the safe planner.

Shady3D: A Robot that Climbs 3D Trusses

Abstract: This paper describes a truss climbing robot we designed and prototyped. The robot has a minimalist design with three motive degrees of freedom that enable movement along three-dimensional truss structures. This robot can form a six-degree-of-freedom structure by connecting to another identical module using a passive bar as a medium. We present the design and implementation of this robot, control algorithms for moving the robot in a 3D truss structure, and hardware experiments

An Acceleration-based State Observer for Robot Manipulators with Elastic Joints

Abstract: Robots that use cycloidal gears, belts, or long shafts for transmitting motion from the motors to the driven rigid links display visco-elastic phenomena that can be assumed to be concentrated at the joints. For the design of advanced, possibly nonlinear, trajectory tracking control laws that are able to fully counteract the vibrations due to joint elasticity, full state feedback is needed. However, no robot with elastic joints has sensors available for its whole state, i.e., for measuring positions and velocities of both motors and links. Several nonlinear observers have been proposed in the past, assuming different reduced sets of measurements. We introduce here a new observer which uses only motor position sensing, together with accelerometers suitably mounted on the links of the robot arm. Its main advantage is that the error dynamics on the estimated state is independent from the dynamic parameters of the robot links, and can be tuned with standard decentralized linear techniques (locally to each joint). We present an experimental validation of this observer for the three base joints of a KUKA KR15/2 industrial robot and illustrate the control use of the obtained results.

Articulated robot for laser ultrasonic inspection

Abstract: An ultrasonic non-destructive evaluation (NDE) system operable to inspect target materials is provided. This ultrasonic NDE system includes an articulated robot, an ultrasound inspection head, a processing module, and a control module. The ultrasound inspection head couples to or mounts on the articulated robot. The ultrasound inspection head is operable to deliver a generation laser beam, a detection laser beam, and collect phase modulated light scattered by the target materials. The processing module processes the phase modulated light and produces information about the internal structure of the target materials. The control module directs the articulated robot to position the ultrasound inspection head according to a predetermined scan plan.

Development of an Adaptive Mobile Robot for In-Pipe Inspection Task

Abstract: For the purpose of performing internal inspection task of pipe, a robot based on adaptive mobile mechanism is developed. The robot equipped with one actuator has two working modes, a normal working mode and an assistant working mode. Robot under normal working mode performs monitoring tasks and travels in the pipe, while under assistant enhanced mode robot will surmount obstacle without any other driving actuator during executing tasks. The special feature is achieved by applying the adaptive mobile mechanism we proposed in this paper. A prototype has been set up and experiments have been conducted to testify the adaptability and efficiency of the robot. The results show that the robot can successfully climb up a step that is formed by concentric junction with a height of 5 mm.

Design and control of a second-generation hyper-redundant mechanism

Abstract: We present a refined, second-generation design, construction and integration, of a compact hyper-redundant snakelike robot, called "Woodstock." This robot has substantial advantages over our previous design iteration, "Snoopy," in terms of cost and performance. The robot is composed of six actuated universal joints which are serially chained to construct a twelve degrees of freedom snake-like robot optimized for strength and compactness. Any joint in the robot is strong enough to produce a torque that is capable of cantilevering the entire robot. This paper also presents the low-level system- control architecture, which is based on a high-speed RS-485 data bus; this allows the entire system to be operated with only two power and two data wires. The system is controlled from a remote computer on a wireless network and can also run over the Internet.

Cooperation of heterogeneous, autonomous robots: A case study of humanoid and wheeled robots

Abstract: In this paper we present a case study of cooperation of a strongly heterogeneous robot team, composed of a highly articulated humanoid robot and a wheeled robot with largely complementing and some competing capabilities. By combining two strongly heterogeneous robots the diversity of accomplishable tasks increases as the variety of sensors and actuators in the robot systems is extended compared with a team consisting of homogeneous robots. The scenario describes a tightly cooperative task, where the humanoid robot and the wheeled robot follow for a long distance a ball, which is kicked finally by the humanoid robot into a goal. The task can be fulfilled successfully by combining the abilities of both robots. For task distribution and allocation, a newly developed objective function is presented which is based on a proper modeling of the sensing, perception, motion and onboard computing capabilities of the cooperating robots. Aspects of reliability and fault tolerance are considered.

Trajectory planning algorithm based on the continuity of jerk

Abstract: This paper presents a trajectory planning method that provides a continuity of position, velocity, acceleration and jerk. The method combines fifth-order and fourth-order polynomials in order to satisfy the continuity of jerk and give smooth accelerations on all segments of the planned trajectory. The proposed method was tested for movements of the three-axes planar articulated robot. The method includes limits of the velocities, accelerations, and jerks of each robot joint. Simulation results are presented and compared with the results obtained by the original Ho and Cook spline-interpolation method.

Tracking control for snake robot joints

Abstract: This paper considers the problem of model based control of the joints of a snake robot without wheels. The potential range of applications for snake robots are numerous, and delicate operations such as inspection and maintenance in industrial environments or performing search and rescue operations require precise control of a snake robot joints. To this end we present a controller that asymptotically stabilizes the joints of the snake robot to a desired reference trajectory. The controller is based on input-output linearization of a control plant model of the snake robot dynamics also developed in this paper. In addition, we provide a formal Lyapunov-based proof of the closed-loop stability, together with simulation results for a smooth dynamical model. Finally, the performance of the controller is tested on a non-smooth snake robot model with set-valued Coulomb friction that offers an accurate description of the stick-slip transitions during locomotion.

Development of a 3D Snake-like Robot: Perambulator-II

Abstract: Snake-like robots exhibited more advantages than conventional mobile robots on environment adaptation. They almost can move in most ill conditions including rough terrain, desert, water, cave and tree. In this paper, a 3D snake-like robot called Perambulator-II (Shenyang Institute of Automation snake-like robot II) is developed with the acquirement of powerful propulsion and high mobility. The unit of snake-like robot Perambulator-II robot named as modular universal unit (MUU) is introduced, which behaves three DOFs with a series of passive rollers around its cylinder body. Also, some considerations on mechanism design of snake-like robots are presented. And the shell shape of 3D snake-like robot according to mobility is discussed in detail. The locomotion of Perambulator-II is presented for test its performance. The experimental results are given to validate the mobility of the snake-like robot Perambulator-II.

Kinematics Analysis and Implementation of a Motion-Following Task for a Humanoid Slave Robot Controlled by an Exoskeleton Master Robot

Abstract: This article presents the kinematic analysis and implementation of an interface and control of two robots-an exoskeleton master robot and a human-like slave robot with two arms. Two robots are designed and built to be used for motion-following tasks. The operator wears the exoskeleton master robot to generate motions, and the slave robot is required to follow after the motion of the master robot. To synchronize the motions of two robots, kinematic analysis is performed to correct the kinematic mismatch between two robots. Hardware implementation of interface and control is done to test motion-following tasks. Experiments are performed to confirm the feasibility of the motion-following tasks by two robots.

A multilegged modular robot that meanders: Investigation of turning maneuvers using its inherent dynamic characteristics

Abstract: This paper deals with the motion of a multilegged modular robot. The robot consists of a set of homogenous modules, each of which has a body and two legs and is connected to the others through a three-degree-of-freedom rotary joint. The leg joints are manipulated to follow periodic desired trajectories, and the joints between the modules act like a passive spring with a damper. This robot has characteristic dynamic properties. Specifically, a straight walk naturally turns into a meandering walk by changing the compliance of the joints between the modules without incorporation of any oscillatory inputs. We first show that this transition is excited due to a Hopf bifurcation, based on a numerical simulation and Floquet analysis. Following that, we examine whether the maneuverability and agility of the robot increase by utilizing the dynamic characteristics inherent in the robot. In particular, we conduct an experiment in which the robot pursues a target moving across the floor. We propose a simple controlle...

A dynamic single actuator vertical climbing robot

Abstract: A climbing robot mechanism is introduced, which uses dynamic movements to climb between two parallel vertical walls. This robot relies on its own internal dynamic motions to gain height, unlike previous mechanisms which are quasi- static. One benefit of dynamics is that it allows climbing with only a single actuated degree of freedom. We show with analysis, simulations and experiments that this dynamic robot is capable of climbing vertically between parallel walls. We introduce simplifications that enable us to obtain closed form approximations of the robot motion. Furthermore, this provides us with some design considerations and insights into the mechanism's ability to climb.

VIsion force control in task-oriented grasping and manipulation

Abstract: In this paper, we present a novel approach for sensor-guided robotic execution of everyday tasks, which is amenable to be integrated in current mobile manipulators and humanoid robots We consider a robot which is observing simultaneously his hand and the object to manipulate, by using an external camera (ie robot head) Task-oriented grasping algorithms are used in order to plan a suitable grasp on the object according to the task to perform A new vision/force coupling approach [1] is used in order to, first, guide the robot hand towards the grasp position and, second, perform the task taking into account external forces Experimental results on a real robot are presented which validate our approach

Kinematic Modelling and Maneuvering of A 5-Axes Articulated Robot Arm

Abstract: This paper features the kinematic modelling of a 5-axis stationary articulated robot arm which is used for doing successful robotic manipulation task in its workspace. To start with, a 5-axes articulated robot was designed entirely from scratch and from indigenous components and a brief kinematic modelling was performed and using this kinematic model, the pick and place task was performed successfully in the work space of the robot. A user friendly GUI was developed in C++ language which was used to perform the successful robotic manipulation task using the developed mathematical kinematic model. This developed kinematic model also incorporates the obstacle avoiding algorithms also during the pick and place operation. Keywords—Robot, Sensors, Kinematics, Computer, Control, PNP, LCD, Software.

Interacting with a human or a humanoid robot

Abstract: Recently, remote-controlled communication robots have been studied. Our question is whether the person interacting with them feels that he/she is interacting with the robot itself or the human behind it. How do such beliefs affect interaction? We conducted an experiment to study the effect of a human presence behind an interactive humanoid robot. We used an interactive robot system based on a motion-capturing system where participants can bodily interact with the robot. They were deceptively informed that they would either be interacting with a robot controlled by a program or a human; in fact, in both conditions the robot was autonomous. Experimental results indicated that two-thirds of the participants felt that they were interacting with the robot itself. Their enjoyment was unaffected by the knowledge of whether the robot was controlled by a program or a human, although their impression of robot intelligence indicated that they distinguished between these conditions. On the contrary, since the remaining one-third of the participants felt they were interacting with a human behind the robot, they were affected by the knowledge: when they were told they were interacting with a teleoperated robot, they enjoyed it less; in contrast, their enjoyment increased when they were told they were interacting with an autonomous robot.

Dynamic force/torque measurement using a 12DOF sensor

Abstract: This article presents an algorithm for dynamic force/torque measurement and robot load identification using the so called 12DOF sensor to measure forces/torques and linear/angular accelerations. The basic equations of dynamic forces and torques arising during robot motion and acting on the end-effector were worked out. To be able to perform the experiments suitable robot system based on a six axes articulated manipulator was constituted. For this system also the appropriate software was developed. The load parameters of the tool were determined during particular motion sequence of the robot and the values were compared with values from CAD software. The compensation of dynamic forces and torques is verified using the experimental robot system and the results are presented.

A Domain-Specific Language for Programming Self-Reconfigurable Robots

Abstract: A self-reconfigurable robot is a robotic device that can change its own shape. Self-reconfigurable robots are commonly built from multiple identical modules that can manipulate each other to change the shape of the robot. The robot can also perform tasks such as locomotion without changing shape. Programming a modular, self-reconfigurable robot is however a complicated task: the robot is essentially a real-time, distributed embedded system, where control and communication paths often are tightly coupled to the current physical configuration of the robot. To facilitate the task of programming modular, self-reconfigurable robots, we have developed a declarative, role-based language that allows the programmer to define roles and behavior independently of the concrete physical structure of the robot. Roles are compiled to mobile code fragments that distribute themselves over the physical structure of the robot using a dedicated virtual machine implemented on the ATRON self-reconfigurable robot.

Obstacle negotiation for the rescue robot with variable single-tracked mechanism

Abstract: The purpose of this paper is to provide a practical introduction to a mobile robot developed for rescue operations. The robot has a variable single-tracked mechanism for the driving part, making it inherently able to overcome indoor obstacles such as stairs. In this research, the robot is given the capacity of obstacle negotiation as a hardware attachment in order to realize autonomous navigation that is well matched to an original target, rescue operation. There are three driving modes to choose from, and the robot recognizes the forward environment once and estimates whether or not any obstacles are there. Experimental results show that the robot moves in opposition to several obstacles, reflecting the proposed algorithm ultimately.

Control system for modular robot based on CAN bus

Abstract: The present invention relates to a modularized control system for an articulated robot, which is based on CAN bus. The present invention is characterized in that the control system comprises a PC, a CAN intelligence interface card, a plurality of control modules (wherein, each control module controls one articulation of the robot), and a CAN bus for connecting the modules and the CAN intelligence interface card. In the control system of the present invention, a two circuit CAN intelligence interface card is connected to the PC by an USB interface at one end, and is connected to the CAN bus by a CAN bus interface at the other end; the control module is connected to the CAN bus. The system and method of the present invention has excellent portability, short development cycle, low cost, regrouping property, fungible property, openness and high stability, and can execute on-line monitoring to robot.

Development and Control Method of Six-Wheel Robot with Rocker Structure

Abstract: In our research group, the project, named "networked robotic system for disaster mitigation", has been carried out to perform robotic victim-search in disaster environment. In this project, we have developed a mobile robots' system which consists of small mobile robots (to search victims in collapsed buildings) and a large-mobile-robot (to convey small robots into it). In order to approach to the target buildings, the large robot is required to surmount some debris and bumpy terrain. For this purpose, the robot has six wheels, and two pairs of wheels in front are formed as actuated rocker structures. This wheel configuration can achieve "active load-equalizer" or other control methods by using load cell data. In this paper, the system description and control methods of the large robot are introduced. We also report a performance of the control methods using a "robot dynamics simulator" developed in our group and preliminary experiments using real robot to evaluate the feasibility of our approach.

Neuro‐adaptive sliding‐mode tracking control of robot manipulators

Abstract: In this work, a new dynamical on-line learning algorithm for robust model-free neuro-adaptive control of a class of nonlinear systems with uncertain dynamics is proposed and experimentally tested in order to evaluate its performance and practical feasibility in industrial settings. The control application studied is the trajectory tracking control task for the first three joints of an open architecture articulated robot manipulator. The control scheme makes use of variable structure systems theory and the feedback-error-learning concept. An inner sliding motion is established in terms of the neurocontroller parameters, aiming to lead the error in its control signal towards zero. The outer sliding motion bears on the system under control, the state tracking error vector of which is simultaneously driven towards the origin of the phase space. The existing relation between the two sliding motions is shown. Experimental results illustrate that the proposed neural-network-based controller possesses a remarkable learning capability to control complex dynamical systems, virtually without requiring a priori knowledge of the plant dynamics and laborious start-up procedures. Copyright © 2007 John Wiley & Sons, Ltd.

Robotic modeling and simulation of palletizer robot using Workspace5

Abstract: Employment of robots in manufacturing has been a value-added entity in a manufacturing industry. Robotic simulation is used to visualize entire robotic application system, to simulate the movement of robot arm incorporated with components consist in its environment and to detect collision between the robot and components. This paper presents result of a project in implementing a computer based model to simulate Okura A1600 palletizer robot. The application uses Okura A1600 robot for palletizing bags at the end of the production line and focuses on pick-and-place application. The project objective is to generate a computer simulated model to represent the actual robot model and its environment. The project simulates the robot's first four joints, namely as the waist, shoulder, elbow and waist and focuses on the position of the robot's end effector, regardless its orientation. Development of the model is using Workspace5 as a simulation tool. Two types of methodology are used, which are the methodology for developing the robotic workcell simulation model and the methodology for executing the robotic simulation. The output of the project will be a three-dimensional view of robot arm movement based on series of predefined geometry points, layout checking and robot's reachability by generating working envelope, collision and near miss detection, and monitoring on the cycle time upon completing a task. The project is an offline programming and no robot language is generated.

Development of a wall climbing robot with wheel-leg hybrid locomotion mechanism

Abstract: A novel prototype of self-contained wall-climbing robot used for special tasks such as rescue, inspection, surveillance and reconnaissance is developed. The wheel-leg hybrid locomotion mechanism enable the robot to achieve quick motion on wall surface, as well as obstacle- spanning on wall surfaces and smooth wall-to-wall transitions. The robot is composed of a base body and a mechanical leg with 3 DOF. The base body is a big flat suction cup with three-wheeled locomotion mechanism inside, and there is a small flat sucker in the end of the mechanical leg. The new designed chamber seal has simple structure and has steady and reliable performance. A distributed embedded control system is also described which enable the robot operating manually and semi-autonomously in wheeled motion mode or legged motion mode. Kinematics model of the robot is established to analyze the robot's motion on the wall. And the locomotion gait of the robot is discussed. Safety analysis of the robot on vertical surfaces shows the robot's reliable adhesion ability to working on wall surfaces.