Showing papers on "Articulated robot published in 2009"

Fast running experiments involving a humanoid robot

Abstract: The present paper describes an implementation of fast running motions involving a humanoid robot. Two important technologies are described: a motion generation and a balance control. The motion generation is a unified way to design both walking and running and can generate the trajectory with the vertical conditions of the Center Of Mass (COM) in short calculation time. The balance control enables a robot to maintain balance by changing the positions of the contact foot dynamically when the robot is disturbed. This control consists of 1) compliance control without force sensors, in which the joints are made compliant by feed-forward torques and adjustment of gains of position control, and 2) feedback control, which uses the measured orientation of the robot's torso used in the motion generation as an initial condition to decide the foot positions. Finally, a human-sized humanoid robot that can run forward at 7.0 [km/h] is presented.

Kinematic Analysis of Robot Manipulators

Abstract: From the Publisher: A robot manipulator is a movable chain of links interconnected by joints. One end is fixed to the ground, and a hand or end effector that can move freely in space is attached at the other end. This book begins with an introduction to the subject of robot manipulators. Next, it describes in detail a forward and reverse analysis for serial robot arms. Most of the text focuses on closed-form solution techniques applied to a broad range of manipulator geometries, from typical industrial robot designs (relatively simple geometries) to the most complicated case of seven general links serially connected by six revolute joints. A unique feature of this text is its detailed analysis of 6R-P and 7R mechanisms. Case studies show how the techniques described in the book are used in real engineering applications. The book meets the need for a thorough, up-to-date analysis of the structure and mobility of serial manipulators and will be useful to both graduate students and engineers working in the field of robotics.

I am my robot: the impact of robot-building and robot form on operators

Abstract: As robots become more pervasive, operators will develop richer relationships with them. In a 2 (robot form: humanoid vs. car) x 2 (assembler: self vs. other) between-participants experiment (N=56), participants assembled either a humanoid or car robot. Participants then used, in the context of a game, either the robot they built or a different robot. Participants showed greater extension of their self-concept into the car robot and preferred the personality of the car robot over the humanoid robot. People showed greater self extension into a robot and preferred the personality of the robot they assembled over a robot they believed to be assembled by another. Implications for the theory and design of robots and human-robot interaction are discussed.

A Reconfigurable Robot With Lockable Cylindrical Joints

Abstract: This paper presents a new conceptual design for reconfigurable robots. Unlike conventional reconfigurable robots, our design does not achieve reconfigurability by utilizing modular joints. Rather, the robot is equipped with passive joints, i.e., joints without actuator or sensor, which permit changing the Denavit-Hartenberg (DH) parameters such as the link length and twist angle. The passive joints will become controllable when the robot forms a closed kinematic chain. Also, each passive joint is equipped with a built-in brake mechanism that is normally locked, but the lock can be released whenever the parameters are to be changed. Such a versatile and agile robot is particularly suitable for space application for its simple, compact, and light design. The kinematics and recalibration of this kind of reconfigurable robot are thoroughly analyzed. A stable reconfiguration-control algorithm is devised to take the robot from one configuration to another by directly regulating the passive joints to the associated, desired DH parameters. Conditions for the observability and the controllability of the passive joints are also derived in detail.

Improving robotic machining accuracy by real-time compensation

Abstract: Although robotics based flexible automation is considered as an ideal solution for foundry pre-machining operation, very few successful installations have been seen due to many major challenges involved in robotic machining processes using conventional articulated robot, such as limited material removal rate, low surface quality, and chatter/vibration. This paper explains the reasons for low surface quality in robotic machining processes and analyzes the stiffness properties of robot structure. Then a real-time compensation algorithm based on a robot stiffness model and force control scheme is introduced. The experimental results show that much better surface quality can be achieved without extending the process cycle time.

Robot interaction system

Abstract: In the case of a robot interaction system comprising a robot (1) having a robot controller with types of operation and operating modes which influence an associated man-robot interface, the aim is to provide a solution which allows flexible matching of a robot or robot system to different degrees of a man-robot interaction. This is achieved in that the robot controller is equipped with types of operation and operating modes which influence an associated man-robot interface and are designed to be matched and/or to be capable of being matched to different automation degrees of the robot (1) and/or to different time and/or physical positions of the man and robot as interaction partners in a working area.

Development of multi-fingered universal robot hand with torque limiter mechanism

Abstract: A multi-fingered universal robot hand has been developed in order to construct the platform of humanoid hand study. We also have developed a small and five-fingered robot hand. The robot hand is designed to protect the small driving system from a large external force. This protection mechanism is small enough to be installed in the joint driving mechanism and adaptable enough to deal with various load. This paper describes basic and unique specifications of the robot hand, and the effectiveness is confirmed by fundamental experiments.

Robot Navigation in Multi-terrain Outdoor Environments

Abstract: This paper presents a methodology for motion planning in outdoor environments that takes into account specific characteristics of the terrain. Instead of decomposing the robot configuration space into "free" and "occupied", we consider the existence of several regions with different navigation costs. In this paper, costs are determined experimentally by navigating the robot through the regions and measuring the influence of the terrain on its motion. We measure the robot's vertical acceleration, which reflects the terrain roughness. The paper presents a hybrid (discrete-continuous) approach to guide and control the robot. After decomposing the map into triangular cells, a path planning algorithm is used to determine a discrete sequence of cells that minimizes the navigation cost. Robot control is accomplished by a fully continuous vector field that drives the robot through the sequence of triangular cells. This vector field allows smooth robot trajectories from any position inside the sequence to the goal, even for a small number of large cells. Moreover, the vector field is terrain dependent in the sense it changes the robot velocity according to the characteristics of the terrain. Experimental results with a differential driven, all-terrain mobile robot illustrate the proposed approach.

Design of an articulated robotic leg with nonlinear series elastic actuation

Abstract: An articulated leg for the use in a running robot is presented. It is driven by series elastic actuation with a highly compliant spring at the knee joint to exploit periodic energy storage and passively support a running motion. The spring is connected with the knee motor by a cable pulley system, which allows the advantageous placement of the motor in the hip joint and enables us to use a compression spring instead of a heavier torsional element. Additionally, the pulley system creates a nonlinear spring characteristic at joint level which can be shaped by altering the cable tension. This nonlinearity and the inertial effects associated with it substantially increase the effective damping in the unloaded leg and allow precise foot-placement during the flight phase. Still, damping of the loaded leg during stance phase is kept minimal for highly efficient energy recovery.

Laneway storehouse stacking robot

Abstract: The utility model provides a palletizing robot, which is composed of a palletizing operative part and a translational part. A base translational screw rod servo motor drives a base translational screw rod, and a base translational screw rod nut realizes the horizontal and linear movement of the palletizing operative part through a base; an arm elevating servo motor drives a rotating shaft through a gear transmission mechanism to realize the rotating movement of a frame; the arm elevating servo motor drives an arm elevating screw rod, and the ascending and the descending of an arm are realized through an arm elevating screw rod nut; a paw telescoping servo motor drives a paw telescoping screw rod, and the extending and the retracting of a paw are realized through a paw telescoping screw rod nut. The stacking and the unstacking of objects are realized through the elevating of the rotating-matched arm of the frame and the telescoping of the paw. The palletizing robot has the advantages that the structure is simple, the palletizing robot is suitable for being operated in a narrow roadway or a warehouse, the utilization effect of the limited volume warehouse is improved, and because the problem that the motion control nonlinearity of the end effector of the traditional articulated robot is overcome, the positional control algorithm of the robot is simple.

Modeling and control of a Delta-3 robot

Abstract: This Master Thesis describes the mathematical modeling of a Delta-3 robot actuated by motors and drive units developed by ELAU GmbH. A given model of the ELAU GmbH drive unit and motor is used when building the Delta-3 robot model including three drive units, one for each motor to be able to actuate the three upper arms. The Delta-3 robot model is divided into kinematics and dynamics parts. The kinematics is used to calculate the trajectories for the three robot arms (joint space) and the corresponding motion of the robot travelling plate (Cartesian space). The Thesis also looks into the robot dynamics, so the coupling effect between the three arms is taken into account in the Simulink model. Different trajectories created with ELAU GmbHs own software are imported to Matlab workspace and simulated with the Simulink model. The results from the Simulink model are compared with the results from a real Delta-3 robot driven by ELAU GmbH hardware and software. The Jacobian matrix for the Delta-3 robot is also calculated to be used in the equations for the coupling effect between the three arms. The Jacobian matrix is also implemented in ELAU GmbH software to be able to calculate the joint velocity or joint acceleration when the TCP velocity or TCP acceleration is known and vice versa. These results can then be used in equations for calculating the torque which is needed for each of the three motors to actuate the upper arms along with the desired TCP trajectory. The torque calculations can be done offline so the real robot don't have to be running, which gives the opportunity to see how much torque each motor needs so the robot is able to follow the desired trajectory for the robots travelling plate. Experiments with comparison between the Simulink model and the real robot are done and the results of the measured values are shown in the Thesis. Also the experiments for the implementation of the Jacobian matrix in ELAU GmbH software are shown in the Thesis. (Less)

Design and analysis of a 3-PPR planar robot with U-shape base

Abstract: In this paper, a planar 3-PPR parallel robot with a non-symmetrical base is proposed. The topology of base platform design is addressed for maximizing the robot's workspace. A robot with U-shape base is designed and analyzed. The new robot reveals some interesting features, such as decoupled degrees of freedom and large reachable and orientational workspace.

An interactive tool for designing complex robot motion patterns

Abstract: Low-cost robots with a large number of degrees of freedom are becoming increasingly popular, nevertheless their programming is still a domain for experts. This paper introduces the Kouretes Motion Editor (KME), a freely-available interactive software tool for designing complex motion patterns on robots with many degrees of freedom using intuitive means. KME allows for a TCP/IP connection to a real or simulated robot, over which various robot poses can be communicated to or from the robot and manipulated locally using the KME graphical user interface. This portability and flexibility enables the user to work under different modes, with different robots, using different host machines. KME is originally designed for the Aldebaran Nao humanoid robot which features a total of 21 degrees of freedom, but can be easily customized for other robots. KME has been employed successfully by Kouretes, the RoboCup team of the Technical University of Crete, for designing various special actions at the RoboCup 2008 competition (Standard Platform League).

A low cost hand-eye calibration method for arc welding robots

Abstract: Hand-eye calibration is one of the most important and fundamental tasks in performing visual guided robot control tasks. Many techniques have been proposed that use various expensive equipment ranging from a three dimensional positioning device to a laser measurement device. The work presented in this paper aims at developing a low cost robot hand/eye calibration method that is accurate and robust enough to be used in a robotic arc welding system. The proposed calibration method allows the camera and object frames to be referenced directly to the robots base co-ordinate frame. Experimental results show that the developed method can be used to achieve a calibration accuracy of 1 mm (in the directions of interest, X and Y axes) that is acceptable for robotic welding applications.

Control-command architecture for a mobile robot using articulated limbs

Abstract: The present invention applies to a mobile robot which can have a human appearance and sophisticated functions enabling it to execute missions. To enable communications internal to the robot to be optimized and allow for a versatility that is both physical (possible substitution of parts of the robot) and software (replacement of programs to adapt it to new missions), an architecture with three computer levels is provided. The highest level comprises the intelligence of the robot which generates commands which are transmitted by an intermediate computer to low-level cards which control the sensors and actuators. Communication between the intermediate computer and the low-level cards is managed by at least one specific secure communication protocol.

The Yobotics-IHMC Lower Body Humanoid Robot

Abstract: This video highlights work to date on the Yobotics-IHMC Lower Body Humanoid Robot. The robot is a twelve degree-of-freedom robot with force controllable Series Elastic Actuators at each degree of freedom. Control algorithms utilize Virtual Model Control, and foot placement is determined using Capture Regions. The robot can recover from moderate disturbances and walk on flat ground. Ongoing work is focused on improving robustness to disturbances, walking more quickly and efficiently, and walking over rough terrain.

Trajectory planning optimization with dynamic modeling of four wheeled omni-directional mobile robots

Abstract: Path planning together with the tuning and determination of controller parameters are major concerns in omnidirectional mobile robots. Defining appropriate controller parameters in acceleration and deceleration to reach far and near target points without slippage is one of critical issues since some troubles due to unregulated velocities may greatly affect the ability of robot for the specified path planning and attaining the mentioned targets. A robot accurate kinematic and dynamic modeling and simulation accompanied by velocity and acceleration filtering are mainly discussed in this paper. Major changes and improvements in motion analysis, simulation and accuracy for the newly presented model and its efficiency are discussed in comparison with the previous simple kinematic modeling. Employing the new approach for robot dynamic modeling, particularly acceleration filtering, results in to the more precise robot control and achieving appropriate results.

Measuring intent in human-robot cooperative manipulation

Abstract: To effectively interact with people in a physically assistive role, robots will need to be able to cooperatively manipulate objects with a human partner. For example, it can be very difficult for an individual to manipulate a long or heavy object. An assistant can help to share the load, and improve the maneuverability of the object. Each partner can communicate objectives (e.g., move around an obstacle or put the object down) via non-verbal cues (e.g., moving the end of the object in a particular direction, changing speed, or tugging). Herein, non-verbal communication in a human-robot coordinated manipulation task is addressed using a small articulated robot arm equipped with a 6-axis wrist mounted force/torque sensor and joint angle encoders. The robot controller uses a Jacobian Transpose velocity PD control scheme with gravity compensation. To aid collaborative manipulation we implement a uniform impedance controller at the robot end-effector with an attractive force to a virtual path in the style of a cobot. Unlike a cobot, this path is recomputed online as a function of user input. In our present research, we utilize force/torque sensor measurements to identify intentional user communications specifying a change in the task direction. We consider the impact of path recomputation and the resulting robot haptic feedback on user physiological response.

Object recognition and obstacle avoidance robot

Abstract: Design highlights of a “Three-wheeled Autonomous Navigational Robot” are presented in this paper. An efficient modular architecture is proposed for ease of adding various modules to the robot. Obstacle detection, pattern recognition and obstacle avoidance are the key aspects of the design. The robot has intelligence built into it that enables it to recognize and pick up balls of a particular colour and ignore other objects in its path. A single board computer mounted on the robot acts as the central controller. It communicates with ultrasonic sensors and motors through multiple microcontrollers and controls the entire motion of the unit. As part of the robot design, a modified H-bridge circuit for driving DC motors efficiently is proposed in this paper.

A rolling robot: Design and implementation

Abstract: Even though many researchers have studied spherical mobile robots, a robot with an elastic external frame can hardly be in the literature. Therefore in this study the pendulum-driven spherical mobile robot is introduced. The external frame of the robot is designed as glass fiber sticks which show good elastic characteristics. All control modules, such as a Zigbee wireless communication module and battery, are embedded into the spherical mobile robot. Atmega 2560-based embedded system is adopted as a main controller to drive the robot along desired path. This study also introduces driving and steering dynamic model of the pendulum-driven type spherical robot and performs experiments to verify the models. Based on the model, a PID controller is implemented and good mobility of the robot is verified.

A lead-through robot programming approach using a 6-DOF wire-based motion tracking device

Abstract: A lead-through robot programming solution with a 6-DOF motion tracking device is presented. The motion tracking device is flexible-linked and can be fixed on the end-effector of a robot to realize lead-through teaching. The programming solution covers data acquiring from the six string sensors of the motion tracking device, data processing, kinematical calculation which converts the sensor signals to the motion tracking device pose, motion planning which generates robot jogging command based on poses of the tracking device and the robot, path recording, smoothing and final robot program generating which takes the recorded path as the input thus a robot can repeat the taught path. A prototype has been built up to verify the programming solution with sound results. With the prototype, different teaching modes can be applied to adapt to different teaching requirements and different application areas.

Design of a differential-drive wheeled robot controller with pulse-width modulation

Abstract: This paper presents mobile robots motion control technique based on pulse-width modulation (PWM). This technique is employed on AMiR which is an autonomous miniature robot for swarm robotic platform. That uses differential drive with a caster wheel configuration. Robot's motors enable to work with different speed in different direction, forward and reverse. A microcontroller as the main processor is deployed to generate motor control pulses and manage duty-cycle of PWM signals. Two methods in robot trajectory control which are rotation and straight movement are described in this paper. Time estimation and also speed selection calculations illustrate the feasibility of this technique to be used in mobile robot motion control problem.

The surface walker: a hemispherical mobile robot with rolling contact constraints

Abstract: In this paper, we propose a new example of non-holonomic mobile robot, which we call the surface walker. This robot is composed of a hemisphere-shaped shell and a 2-d.o.f. mass-control device (pendulum) inside it, and undergoes the rolling contact constraint between the hemispherical surface of the robot and the ground. Unlike a lot of non-holonomic robots which have ever been researched, the drift term exists in the system of the hemisphere robot. First, we show basic concepts which the hemisphere robot has, and construct the kinetic model of this robot. Then we realize the locomotion control of the robot by periodically oscillating the internal pendulum and show its effectiveness by control experiments.

Floor‐cleaning robot using omni‐directional wheels

Abstract: Purpose – The purpose of this paper is to present an omni‐directional floor‐cleaning robot equipped with four omni‐directional wheels. The research purposes are to design a robot for cleaning jobs in domestic, narrow and crowded places and to provide a robotics‐study platform in a laboratory.Design/methodology/approach – The robot system using Swedish wheels, one dust collector (brush) switching device and a sort of air‐bag sensing device is designed. The kinematics and the motion control conditions of the robot are analyzed. Specifically, a design method of wheels is described.Findings – The configuration of the robot, parameters of the wheel and controlling methods are studied and demonstrated. The smooth locomotion capability and high‐working efficiency are verified by experiments.Practical implications – The robot can perform its work in semi‐autonomous and tele‐operated mode. Moreover, the robot can pivot around, avoid obstacles and is provided with automatic power management system.Originality/value...

Online motion planning for HOAP-2 humanoid robot navigation

Abstract: Autonomous robot navigation is becoming an increasingly important research topic for mobile robots. In the last few years, significant progress has been made towards stable robotic bipedal walking. This is creating an increased research interest in developing autonomous navigation strategies which are tailored specifically to humanoid robots. Efficient approaches to perception and motion planning, which are suited to the unique characteristics of biped humanoid robots and their typical operating environments, are receiving special interest. In this paper, we present a time-efficient motion planning system for a Fujitsu HOAP-2 humanoid robot. The sampling based algorithm is used to provide the robot with minimal free configuration space which is sampled to extract the robot path. For collision detection, a cylinder model is used to approximate the trajectory for the body center of the humanoid robot during navigation. It calculates the actual distances required to execute different actions of the robot and compares them with the distances to the nearest obstacles. The A* search algorithm is then implemented to find smooth and low-cost footstep placements of the humanoid robot within the resulting configuration space. The proposed hybrid algorithm reduces searching time and produces a smoother path for the humanoid robot at a low cost.

Design and Motion Analysis of an In-pipe Robot with Adaptability to Pipe Diameters

Abstract: For the purpose of pipe inspection,an adaptive mobile mechanism is proposed and a robot based on this mechanism is designed and developed.Due to the unique transmission mechanism the robot has the adaptability to the change of pipe diameters, while number of the driving actuator does not increase.When the robot encounters a step,the adaptive mobile mechanism of the robot will change its working mode to surmount the obstacle.Compared to classical screw-driven robots,this robot does not employ the link-type configuration,but only uses one actuator to solve the low capability of surmounting obstacle.The observed rotation problem of the supporting parts is solved by the kinematical analysis of the robot.Basic experiments are performed to testify the adaptability and efficiency of the robot.

Parent-child robot system for rescue missions

Abstract: High mobility, large obstacle performance, narrow space crossing-over capacity and stable data communication are important features for a rescue robot. The authors proposed a parent-child robot system that could achieve all of these abilities. The robot system is composed of a parent robot, a tracked child robot and a legged robot. The parent robot has high mobility and can climb over ordinary obstacles. The tracked child robot is relatively small and high mobility surveyor type. The legged child robot is also small and surveyor type as well, which has superior adaptability in narrow spaces. To achieve the mission, the parent robot first carries the two child robots to collect information about disaster and victims. When the parent robot encounters narrow space which it cannot get through, the child robots are released from the body of the parent robot by a manipulator to search for details in the narrow space. Meanwhile, the parent robot can be controlled to perform tasks in another place. When the parent robot detects that the wireless signal intensity is too low to communicate with the operator, the child robots can also be released as a network node to expand the area of the wireless network. So far we have developed prototypes of each robot. We have also proposed a method which confirms to be effective, using Zigbee and electronic compass to estimate the localization of the three robots. Finally, we put the three robots in test situations to simulate the disaster scenarios. The experimental results showed that the grouping parent-child robots have a strong ability to adapt the disaster situation.

A Mobile Robot Platform with Double Angle-Changeable Tracks

Abstract: This paper presents a different structured mobile robot platform (MRP) with double tracks, which consists of two segments connected with a swing joint. As the angle between the two segments of the ...