Position Error Of Robot Research Articles

Hybrid vision-based navigation for mobile robots in mixed indoor/outdoor environments

In this paper we present a vision-based navigation system for mobile robots equipped with a single, off-the-shelf camera in mixed indoor/outdoor environments. A hybrid approach is proposed, based on the teach-and-replay technique, which combines a path-following and a feature-based navigation algorithm. We describe the navigation algorithms and show that both of them correct the robot’s lateral displacement from the intended path. After that, we claim that even though neither of the methods explicitly estimates the robot position, the heading corrections themselves keep the robot position error bound. We show that combination of the methods outperforms the pure feature-based approach in terms of localization precision and that this combination reduces map size and simplifies the learning phase. Experiments in mixed indoor/outdoor environments were carried out with a wheeled and a tracked mobile robots in order to demonstrate the validity and the benefits of the hybrid approach.

Research on Absolute Positioning Error of Robot Based on Mapping Theory

Joint-typical Industrial robots tend to have higher repetitive positioning accuracy and lower absolute positioning accuracy. In order to improve the absolute positioning accuracy of robots, this paper puts forward a compensation algorithm based on the mapping theory combining with the kinematics equation, which establish the connection between the space of off-line programming and teaching-programming, so as to approximate the repeat positioning accuracy. A experiment is implemented to confirm its correctness, and the result shows that the supposed method can improve the absolute positioning accuracy heavily, which the absolute positioning error reduces from 8.32mm to 1.08mm.

Error Analysis of 6-DOF Welding Robot

Welding robot has the advantages that welding quality stability, high efficiency, improving the working conditions of workers, and it is widely applied in the manufacturing sector. A six degree of freedom welding robot configuration is presented in this paper. The kinematics model of the robot is established by DH method and its kinematics was analyzed. At last the error model of the position-pose of the robot end-effecter, produced by the influence of robot joint movement variables deviation and structure deviation, was established by the differential method. The deviation influence on the end-effecter was analyzed by numerical simulation. The results prove the error model is right, and they will provide a reliable basis for robot position error compensation and accuracy optimum design.

Proposal of a Masticatory Robot for Analysis of Jaw Movements

In this paper, a life-sized jaw mechanism is proposed on the basis of biological masticatory structure. Its actual parameters are defined in Solidworks according to human masticatory systems, the trajectory and position error of masticatory robot is performed via ADAMS and Matlab. The simulation results have shown that the robotic jaw is able to reproduce the human behavior. However, because the mechanism is a highly coupled and nonlinear system, the position error cannot be eliminated completely, and more sophisticated control system is required in future study.

Research on Deformation Error of Links of Parallel Robot

Aimed at the effect problem of deformation of links on position error of parallel robot, the 3-TPT parallel robot is taken as a study object. The deformation error of links of parallel robot was built by error independent principle based on kinematics; the simulation analysis also is carried out by virtual prototype technique, and the effect law of deformation of links to error of parallel robot is given. The results showed that when the deformation length of links is given, the position error can be affected by deformation of each link and the coordinate position of origin in reference frame; In the beginning of parallel robot moving, the deformation of links are small, and with the time increasing, the deformation of links obviously affect the final position error of parallel robot. The two method proposed in this paper can be used for pre-estimating the error and reducing harmful effects.

Analysis and Control of Robot Position Error in SLAM

摘要: 移动机器人同步定位与建图问题 (Simultaneous localization and mapping, SLAM) 是机器人能否在未知环境中实现完全自主的关键问题之一. 其中, 机器人定位估计对于保持地图的一致性非常重要. 本文分析了 SLAM 问题中机器人定位误差的收敛特性. 分析表明随着机器人的运动,机器人定位误差总体上逐渐增大; 在完全未知环境中无法预测机器人定位误差的上限. 根据理论分析, 本文提出了一种控制机器人定位误差在单位距离上增长速度的算法. 该算法通过搜索获得满足定位误差限制的最佳的机器人运动速度, 从而控制机器人定位误差的增长. 关键词: SLAM问题 / 移动机器人 / 定位误差 / 误差控制

실시간 환경에서의 영상조정 및 패치 변경에 의한 축구로봇의 성능개선

본 논문에서는 카메라 렌즈에서 흔히 발생할 수 있는 렌즈의 왜곡에 의한 화상을 보정하고, 로봇 좌표를 인식하기 위해 사용하는 패치의 변경에 의한 로봇의 위치 및 각도오차를 줄여 축구로봇 시스템의 성능 개선에 대한 새로운 방법을 제시한다. 그리고 렌즈의 왜곡 중 기하학적인 왜곡을 보정하여 로봇의 위치오차를 줄여 실시간 환경인 축구로봇 시스템에 적용한다. 로봇의 인식과 로봇의 좌표 및 방향을 판별하기 위하여 사용하는 패치는 그 모양에 따라 로봇이 가지게 되는 위치오차와 각도오차가 발생하게 된다. 본 논문에서는 개선한 로봇패치에 따른 로봇의 위치 및 각도 오차를 줄이는 방법을 제안하고 실험을 통하여 이를 검증하였다.

A nonlinear model predictive control strategy for trajectory tracking of a four‐wheeled omnidirectional mobile robot

AbstractThis paper presents a nonlinear model‐based predictive controller (NMPC) for trajectory tracking of a four‐wheeled omnidirectional mobile robot. Methods of numerical optimization to perform real‐time nonlinear minimization of the cost function are used. The cost function penalizes the robot's position error, the robot's orientation angle error, and the control effort. Experimental results of the trajectories following and the performances of the methods of optimization are presented. Copyright © 2007 John Wiley & Sons, Ltd.

Statistical error analysis and calibration of industrial robots for precision manufacturing

This paper presents a new perspective on the calibration of industrial robotics systems by describing robot position errors as time varying variations of the actual positions of the end-effector from the target position, the error calibration of a robotics manipulator is treated as a “process” rather than a “state”. Therefore the theory of variations is applicable. The importance of distinguishing the two kinds of variations, namely random system variations and assignable variations, in a robot calibration process is demonstrated through a Monte Carlo simulation.

A Method for Determining and Correcting Robot Position and Orientation Errors Due to Manufacturing

A method is presented for calibration of a robot to correct position and orientation errors due to manufacturing. The method is based on the shape matrix robot kinematic description. Each joint is individually and successively moved in order to explicitly calculate the shape matrix of each link. In addition, methods to correct for the errors in both the forward and inverse kinematic solutions are presented. The modification of the forward solution is a simple task. The modification of the inverse kinematic solution is a difficult problem and is achieved by an iterative technique which supplements the closed-form solution. An example of the calibration and inverse solution is presented to show the improvement in the accuracy of the robot.