Showing papers on "Articulated robot published in 2005"

Design and implementation of a multi-section continuum robot: Air-Octor

Abstract: In this paper, we describe the design and implementation of a novel multi-section, continuous-backbone ("continuum") robot. The design is based on an innovative "hose-in-hose" concept. Its implementation is novel with respect to previous continuum robot designs in that stiffness and extension, in addition to bending, are actively controlled in each section of the robot. This requires a non-trivial extension of previously proposed kinematic models, and poses challenges for real-time control of the robot. We introduce a tangling/untangling algorithm to map between overall cable lengths and per-section cable lengths. Details of the design and its implementation are presented, along with a summary of real-time control issues and experimental results.

Dynamic Analysis of a Nonholonomic Two-Wheeled Inverted Pendulum Robot

Abstract: As a result of the increase in robots in various fields, the mechanical stability of specific robots has become an important subject of research. This study is concerned with the development of a two-wheeled inverted pendulum robot that can be applied to an intelligent, mobile home robot. This kind of robotic mechanism has an innately clumsy motion for stabilizing the robot's body posture. To analyze and execute this robotic mechanism, we investigated the exact dynamics of the mechanism with the aid of 3-DOF modeling. By using the governing equations of motion, we analyzed important issues in the dynamics of a situation with an inclined surface and also the effect of the turning motion on the stability of the robot. For the experiments, the mechanical robot was constructed with various sensors. Its application to a two-dimensional floor environment was confirmed by experiments on factors such as balancing, rectilinear motion, and spinning motion.

A visually guided swimming robot

Abstract: We describe recent results obtained with AQUA, a mobile robot capable of swimming, walking and amphibious operation. Designed to rely primarily on visual sensors, the AQUA robot uses vision to navigate underwater using servo-based guidance, and also to obtain high-resolution range scans of its local environment. This paper describes some of the pragmatic and logistic obstacles encountered, and provides an overview of some of the basic capabilities of the vehicle and its associated sensors. Moreover, this paper presents the first ever amphibious transition from walking to swimming.

Proposed wall climbing robot with permanent magnetic tracks for inspecting oil tanks

Abstract: This paper presents a proposed research on the wall climbing robot with permanent magnetic tracks. A brief review about the wall climbing robot is given, different prototypes of wall climbing robot are compared, and the different application fields are introduced. A proposed wall climbing robot with permanent magnetic adhesion mechanism for inspecting oil tanks is put forward. The mechanical system architecture is detailed in the paper. By analyzing the robot's workspace, permanent magnetic adhesion mechanism is chosen for the robot. Also, tracked locomotion mechanism is applied to the robot. By static and dynamic force analysis of the robot, design parameters about adhesion and locomotion mechanism are derived. In addition, safety constraints for the robot are obtained. Finally, the electrical system architecture for the robot is offered. To improve the efficiency, hierarchy control architecture is employed in the robot system. An embedded system is used and installed in the robot to manage multiple sensors and to communicate with the master computer through the wireless link. And the Web-based teleoperation for the robot is illustrated in the paper.

Five-fingered Robot Hand using Ultrasonic Motors and Elastic Elements

Abstract: A five-fingered robot hand having almost an equal number of DOF to the human hand is developed. The robot hand is driven by a unique method using ultrasonic motors and elastic elements. The method makes use of restoring force as driving power in grasping objects, which enables the hand to perform stable and compliant grasping motion without power supply. In addition, all the components are placed inside the hand because the ultrasonic motors have characteristics of high torque at low speed and compact size. Applying the driving method to a multi-DOF mechanism, a five-fingered robot hand is designed. The robot hand has twenty joints and DOF. It is almost equal in size to the hand of an average grown-up man. The robot hand is produced, and control experiments are conducted. As a result, the potential of the robot hand is confirmed.

Off-line programming of an industrial robot for manufacturing

Abstract: A procedure for the automatic generation of the robot programming used in manufacturing operations is introduced in the present paper. The off-line programming system developed here includes graphical simulation of the robot and its workcell, kinematic model of the robot, motion planning and creation of the NC code for manufacturing process. The proposed system is applied in a robot with five revolute joints for manufacturing operations and in a robot with six revolute joints for welding operations.

Optimal robot task scheduling based on genetic algorithms

Abstract: Industrial robots should perform complex tasks in the minimum possible cycle time in order to obtain high productivity. The problem of determining the optimum route of a manipulator's end effector visiting a number of task points is similar but not identical to the well-known travelling salesman problem (TSP). Adapting TSP to Robotics, the measure to be optimized is the time instead of the distance. In addition, the travel time between any two points is significantly affected by the choice of the manipulator's configuration. Therefore, the multiple solutions of the inverse kinematics problem should be taken into consideration. In this paper, a method is introduced to determine the optimum sequence of task points visited by the tip of the end effector of an articulated robot and it can be applied to any non-redundant manipulator. This method is based on genetic algorithms and an innovative encoding is introduced to take into account the multiple solutions of the inverse kinematic problem. The results show that the method can determine the optimum sequence of a considerable number of task points for robots up to six-degrees of freedom.

Safe planning for human-robot interaction

Abstract: This paper presents a strategy for improving the safety of human-robot interaction by minimizing a danger criterion during the planning stage. This strategy is one part of the overall methodology for safe planning and control in human-robot interaction. The focus application is a hand-off task between an articulated robot and an inexpert human user. Two formulations of the danger criterion are proposed: a criterion assuming independent safety-related factors, and a criterion assuming mutually dependent factors. Simulations of the proposed planning strategy are presented for both 2D and 3D robots. The results indicate that a criterion based on scaled mutually dependent factors such as the robot inertia and the human robot distance generates safe, feasible paths for interaction. © 2005 Wiley Periodicals, Inc.

Cascaded control concept of a robot with two degrees of freedom driven by four artificial pneumatic muscle actuators

Abstract: Pneumatic muscles are interesting in their use as actuators in robotics, since they have a high power/weight ratio, a high-tension force and a long durability. This paper presents a two-axis planar articulated robot, which is driven by four pneumatic muscles. Every actuator is supplied by one electronic servo valve in 3/3-way function. Part of this work is the derivation of the model description, which describes a high nonlinear dynamic behavior of the robot. Main focus is the physical model for the pneumatic muscle and a detailed model description for the servo valves. The aim is to control the tool center point (TCP) of the manipulator, which bases here on a fast subsidiary torque regulator of the drive system compensating the nonlinear effects. As the robot represents a MIMO system, a second control objective is defined, which corresponds here to the average pressure of each muscle-pair. An optimisation-strategy is presented to meet the maximum stiffness of the controlled drive system. As the torque controller assures a fast linear input/output behavior, a standardized controller is implemented which bases here on the Computed Torque Method to track the TCP. Measurement results show the efficiency of the presented cascaded control concept.

Blending human and robot inputs for sliding scale autonomy

Abstract: Most robot systems have discrete autonomy levels, if they possess more than a single autonomy level. A user or the robot may switch between these discrete modes, but the robot can not operate at a level between any two modes. We have developed a sliding scale autonomy system that allows autonomy levels to be created and changed on the fly. This paper discusses the system's architecture and presents the results of experiments with the sliding scale autonomy system.

Dimensional Synthesis of Parallel Robots with a Guaranteed Given Accuracy over a Specific Workspace

Abstract: We are considering a n d.o.f. parallel robot that has to move within a given workspace and whose geometry is defined by a set of parameters. The motion of active joints of the manipulator are measured with sensors with a known accuracy ±Δρ. These errors together with bounded manufacturing errors on the parameters describing the geometry of the robot induces a positioning errors ΔX of the platform. We present an algorithm that allows one to determine geometries of the robot ensuring that these positioning errors will lie within pre-specified limits for any pose of the robot in its workspace even if the physical realization of the robot differs from the theoretical model while staying within the given manufacturing errors bounds. A by-product variant of this algorithm allows one to compute the maximal positioning errors of a given robot up to a predefined accuracy.

Horizontal articulated robot

Abstract: A horizontal articulated robot has a plurality of horizontal arms coupled by joint shafts, and a working shaft disposed at the extreme end of an extreme end arm among the horizontal arms has mounting portions of an end effector formed to both the upper and lower ends thereof. With this arrangement, there can be provided a horizontal articulated robot that can cope with various work transport forms and various types of works by one type of a robot by selectively using the upper and lower sides of a working shaft.

Robot with learning control function and method for controlling the robot

Abstract: A robot with a learning control function for improving the accuracy of the trajectory of an end effector and a method for controlling the robot. An acceleration sensor and a vision sensor are attached to the end effector of the robot. In this state, the motion of the end effector is measured and a test operation of a motion program is repeatedly executed, whereby a robot control device learns an optimized motion of the robot. In a subsequent actual operation, the acceleration sensor and the vision sensor are not used and the motion of the robot is executed based on the learned optimized motion. The sensors may be removed during the actual operation.

Design and implementation of a control IC for vertical articulated robot arm using SOPC technology

Abstract: A servo control IC for vertical articulated robot arm using SOPC (system-on-a-programmable-chip) technology is presented in this paper. The SOPC technology, developed by Altera Corporation, consists of a FPGA (field programmable gate array) and a Nios embedded processor. In this proposed servo control IC, there are two modules. One module performs the functions of the sequential control, the motion trajectory control and five-axis position control. The other module performs the functions of the five sets of PWM (pulse width modulation) generation and QEP (quadrature encoder pulse) capture. The former is implemented by software using Nios embedded processor due to the need of complicated control algorithm and low sampling frequency control (motion trajectory control & position control: less than 1 kHz). The latter is implemented by hardware using PLD (programmable logic device) in FPGA due to the need of high sampling frequency control (PWM circuit: 18 kHz, peripheral circuits: 4~8 MHz) but simple computation. As the result, the use of the SOPC technology can make the controller of the vertical articulated robot arm more compact, high performance and cost down.

Design and development of a light weight embodied robotic hand activated with only one actuator

Abstract: At the present time, the robotics hand research field is searching for those robots that could imitate the human hand, both in shape and in skill. As another option, some manipulator are developed, even though they do not imitate the human hand, they try to fulfil certain specific tasks with the biggest precision and skill. Some keys to make the robotic hands integrable in any manipulator are: built them lighter, a minimum amount of actuators and a simple sensorial system to simplify its control. The present work will describe the design of the RL1 Hand developed in the Robotic's Lab at the Carlos III University of Madrid. This robotic hand has 3 articulated fingers, which adapt themselves to the object which is being held. The fingers movement and auctioning are made through one direct current motor. The control is done through simple commands and can be sent from any computer, as a string of characters. To prove its ability the RL1 Hand was mounted in a robotic arm, ASIBOT Robot. This arm was developed to help disabled people or people with special needs. The RL1 Hand, its mechanisms, its electronic control and its actuator weight 250gr and they are embodied in the ASIBOT Robot.

Gait Planning of Quadruped Walking and Climbing Robot for Locomotion in 3D Environment

Abstract: One of the traditional problems in the walking and climbing robot moving in the 3D environment is how to negotiate the boundary of two plain surfaces such as corners, which may be convex or concave. In this paper a practical gait planning algorithm in the transition region of the boundary is proposed in terms of a geometrical view. The trajectory of the body is derived from the geometrical analysis of the relationship between the robot and the environment. And the position of each foot is determined by using parameters associated with the hip and the ankle of the robot. In each case of concave or convex boundaries, the trajectory that the robot moves along is determined in advance and the foot positions of the robot associated with the trajectory are computed, accordingly. The usefulness of the proposed method is confirmed through simulations and demonstrations with a walking and climbing robot.

Design and implementation of reconfigurable modular humanoid robot architecture

Abstract: This paper describes the design and implementation of reconfigurable modular humanoid robot architecture. Our proposed architecture features three key concepts: 1) a reconfigurable mechanical structure; 2) a layered software model; and 3) an end-to-end real-time communication mechanism. Our proposed reconfigurable modular humanoid robot consists of several functional robots such as an arm robot, a mobile robot, and a head robot to realize an effective reconfigurable mechanism for expandability. Depending on many purposes of researchers and users, our reconfigurable modular humanoid robot can be used as some kinds of humanoid robots or as several autonomous functional robots. We design and develop a prototype modular humanoid robot consisting of five functional robots for evaluating our proposed architecture. The results of the experiences show the modular humanoid robot can achieve expandability by our reconfigurable mechanism.

Robot Workspace Optimization Based on a Novel Local and Global Performance Indices

Abstract: In this paper, a novel performance index is introduced for the kinematics optimization of serial robot manipulators. The serial robot manipulators used in order to compare optimization results were classified as in (1). The new performance index is a combination of a manipulability measure and condition number used by previous authors. To find the optimum link lengths and volumes of these robot manipulators, two design objectives are used: maximize the workspace area covered by the robot manipulator and maximize the new local index. As examples, two spherical three-link robot manipulators are examined based on above design objectives. Finally, optimization results of these robot manipulators are obtained and compared to each other. Generally speaking, a robot manipulator structure can be subdivided into a regional structure and orientation structure. The regional structure consists of the arm (first three links), which moves the end-effector to a desired position in the workspace of the robot manipulator. The orientation structure, comprised of the last three links, rotates the end- effector to the desired orientation in the workspace. In this study, the regional structure of the robot manipulators is examined rather then the orientation structure.

System and method for controlling modular robots

Abstract: Techniques are described for control of a robot system, wherein the robot system includes a plurality of individual wheeled robot modules interconnected by at least one compliant member. The technique includes developing a kinematic control model of the robot system from a combination of the kinematic characteristics of the individual wheeled robot modules and the stiffness properties of the compliant member. Development of the kinematic control model for a reconfigurable robot system is enhanced by the scalable nature of the technique.

Painting brush control techniques in Chinese painting robot

Abstract: This paper describes a Chinese painting robot (CP robot) that can be categorized as an art robot. The whole system consists of a robot arm, robot hand, Chinese brush, and system controller. In Chinese painting, the following four objects: bamboos, plum blossoms, chrysanthemums, and orchids are often used to practice painting techniques. This paper focuses on how to draw bamboos by a CP robot. When a bamboo drawing is presented, the CP robot decomposes the drawing into stems, joints, branches, and leaves. According to the drawing order information, the system controller creates the trajectory of the Chinese brush. The trajectory of the Chinese brush is considered as B-spline curves determined by the points included in the drawing order information. The trajectory and the pressure control information are sent to the CP robot to imitate painter's behavior. The experiment results show that the proposed techniques are efficient for the CP robot to perform the fundamental drawing in Chinese painting.

Recognizing interaction from a robot's perspective

Abstract: For meaningful interaction between a robot and a human, an autonomous robot must recognize whether the experienced situation is created by people or by the environment. Using only proprioceptive data from a mobile robotic platform, we discover that it is possible to distinguish sensory data patterns involving interaction. These patterns are obtained whilst navigating varying environments, both human populated and unpopulated. The paper reports the initial set of trials using Roball, a spherical mobile robot. Also described is the experimental methodology currently followed to validate the hypothesis that child interaction can be perceived directly from navigation sensors onboard a robotic platform.

Experiments in Vision-Guided Robot Walking in a Structured Scenario

Abstract: Locomotion of a biped robot in a scenario with obstacles requires a high degree of coordination between perception and walking. This article presents key ideas of a vision-based strategy for guidance of walking robots in structured scenarios. Computer vision techniques are employed for reactive adaptation of step sequences allowing a robot to step over or upon or walk around obstacles. A highly accurate visual feedback is achieved by a combination of line-based scene analysis and real-time feature tracking. The proposed vision-based approach was evaluated by experiments with a real humanoid robot. I. INTRODUCTION

Simultaneous Calibration of Action and Sensor Models on a Mobile Robot

Abstract: This paper presents a technique for the Simultaneous Calibration of Action and Sensor Models (SCASM) on a mobile robot. While previous approaches to calibration make use of an independent source of feedback, SCASM is unsupervised, in that it does not receive any well-calibrated feedback about its location. Starting with only an inaccurate action model, it learns accurate relative action and sensor models. Furthermore, SCASM is fully autonomous, in that it operates with no human supervision. SCASM is fully implemented and tested on a Sony Aibo ERS-7 robot.

Motion Control of a Micro Biped Robot for Nondestructive Structure Inspection

Abstract: For the aircraft structure inspection, this paper introduces a micro biped robot with inspection probe and wireless vision, analyzes the robot locomotion modes and dynamic models, and studies the motion control algorithm. Considering the movement flexibility caused by five degrees of freedom, a hierarchy structure is presented for the robot motion control system. For the long distance locating problem, a relay locating approach is presented to solve robot locating and to estimate the orientation of the robot by using vision and distance information from encoder and CAD model. The movement orientation can be adjusted rivet by rivet in the inspection process. The experimental results show that the control algorithm works well, and orientation estimation algorithm provides an acceptable orientation precision for continuous rivet inspection.

Mechanism design and motion analysis of a spherical mobile robot

Abstract: A new spherical mobile robot BHQ-1 is designed. The spherical robot is driven by two internally mounted motors that induce the ball to move straight and turn around on a flat surface. A dynamic model of the robot is developed with Lagrange method and factors affecting the driving torque of two motors are analyzed. The relationship between the turning radius of the robot and the length of two links is discussed in order to optimize its mechanism design. Simulation and experimental results demonstrate the good controllability and motion performance of BHQ-1.

Development of a Five-fingered Robot Hand using Ultrasonic Motors and Elastic Elements

Abstract: A robot hand imitating human hand is developed. The robot hand is driven by a new method proposed by authors using ultrasonic motors and elastic elements. The method utilizes restoring force of elastic element as driving power for grasping an object, so that the hand can perform the soft and stable grasping motion with no power supply. In addition, all the components oare placed inside the hand thanks to the ultrasonic motors with compact size and high torque at low speed. Applying the driving method to multi-DOF mechanism, a five-fingered robot hand is designed and implemented. It has equal number of joints and DOF to human hand, and it is also equal in size to the hand of average adult male. The performance of the robot finger is confirmed by fundamental driving experiments.