A Semi Closed Loop Compensation Method for Trajectory Error of Continuum Robot Based on Vector Method

2019 ◽  
Author(s):  
Pengyu Wang ◽  
Guohua Gao
Keyword(s):  
Closed Loop ◽  
Compensation Method ◽  
Vector Method ◽  
Trajectory Error ◽  
Continuum Robot

scholarly journals A Concentric Tube Continuum Robot with Piezoelectric Actuation for MRI-Guided Closed-Loop Targeting

2016 ◽  
Vol 44 (10) ◽  
pp. 2863-2873 ◽  
Author(s):  
Hao Su ◽  
Gang Li ◽  
D. Caleb Rucker ◽  
Robert J. Webster III ◽  
Gregory S. Fischer
Keyword(s):  
Closed Loop ◽  
Piezoelectric Actuation ◽  
Continuum Robot ◽  
Mri Guided

Design of 2_DOF Simulation Platform for the Testing of Airborne Laser Communication APT System

2014 ◽  
Vol 989-994 ◽  
pp. 3683-3688
Author(s):  
Li Xin Meng ◽  
Ding Xuan Zhao ◽  
Yang Yang Bai ◽  
Li Zhong Zhang
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Closed Loop ◽  
Laser Communication ◽  
Motion Simulation ◽  
Vector Method ◽  
Kinematics Model ◽  
Airborne Laser ◽  
Model And Simulation ◽  
Simulation Results

Lightweight, flexible motion simulation is the demand of airborne laser communication optical transceive when apply to outside test. A new parallel 2_DOF platform that has the function of azimuth and pitching is put forword based on the analysis of airplane position-pose changes affect the performance airborne laster communication APT system, and the kinematics model is established by using closed-loop vector method. Kinematics model is right through the comparison of mathematical model and simulation results of ADAMS, which provides the reference and basis for the design of control system.

scholarly journals Kinematic Analysis and Verification of a New 5-DOF Parallel Mechanism

2021 ◽  
Vol 11 (17) ◽  
pp. 8157
Author(s):  
Yesong Wang ◽  
Changhuai Lyu ◽  
Jiang Liu
Keyword(s):  
Parallel Mechanism ◽  
Closed Loop ◽  
Three Dimensional ◽  
Line Geometry ◽  
Vector Method ◽  
Five Dimensions ◽  
Grassmann Line Geometry ◽  
Working Performance ◽  
Geometry Method ◽  
Unstable Problem

This paper first designs a new 5-DOF parallel mechanism with 5PUS-UPU, and then analyses its DOF by traditional Grubler–Kutzbach and motion spiral theory. It theoretically shows that the mechanism meets the requirement of five dimensions of freedoms including three-dimensional movement and two-dimensional rotation. Based on this, the real mechanism is built, but unfortunately it is found unstable in some positions. Grassmann line geometry method is applied to analyze its unstable problem caused by singular posture, and then an improving method is put forward to solve it. With the improved mechanism, closed loop vector method is employed to establish the inverse position equation of the parallel mechanism, and kinematics analysis is carried out to get the mapping relationships between position, speed, and acceleration of moving and fixed platform. Monte Carlo method is used to analyze the workspace of the mechanism, to explore the influencing factors of workspace, and then to get the better workspace. Finally, an experiment is designed to verify the mechanism working performance.

scholarly journals Dynamics Modeling and Analysis of a Novel Constraint Metamorphic Reversible Plough

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Yanyan Song ◽  
Boyan Chang ◽  
Guoguang Jin ◽  
Zhan Wei ◽  
Bo Li
Keyword(s):  
Closed Loop ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Initial Position ◽  
Dynamics Modeling ◽  
Constraint Force ◽  
Vector Method ◽  
Modeling And Analysis ◽  
Acceleration Analysis ◽  
Source Phase

To meet the requirements of different farming objects, this paper presents a novel constraint metamorphic reversible plough (CMRP) which has four distinct working phases and the feature of underactuation, and its prototype has been manufactured for practical testing purposes. Firstly, the kinematics of the mechanism in each phase are studied systematically with the closed-loop vector method, including displacement, velocity, and acceleration analysis. Considering the underactuated characteristics of the mechanism in the source phase, its dynamic models in the source phase are further established by the Lagrange equation. Based on the theory that velocity and acceleration are the same in an extremely brief period, the motion laws of the slider in the source phase can be obtained. To obtain the constraint force/torque acting on the crucial joints in each phase, the dynamic model of the CMRP is established by the Newton–Euler equation. Furthermore, the initial position of the CMRP with a flexible prismatic joint can be determined using the static balance equation. Finally, the obtained kinematic and dynamic models of the CMRP in each phase are verified, respectively, through comparing the simulation results in SolidWorks and Matlab software, and the experiment with the prototype is conducted. The CMRP proposed in this study provides a feasible technical scheme for improving the capability of reversible plough over unknown and complex terrains.

Imitation Study of Hybrid-Driven Five-Bar Mechanism Output Movement Characteristic Based on Kinematics Analysis

2010 ◽  
Vol 44-47 ◽  
pp. 2728-2732
Author(s):  
Ning Shan
Keyword(s):  
Closed Loop ◽  
Low Cost ◽  
Mathematic Model ◽  
Original Position ◽  
Kinematics Analysis ◽  
Vector Method ◽  
Movement Characteristic ◽  
Movement Parameters

Hybrid-driven five-bar mechanism that combines the motions of two characteristically different motors can attain the flexibility output movement. Its structure is simply and it has low cost. Therefore it is widely used manufacture fields. In this paper, the kinematics mathematic model of plane closed-loop five-bar mechanism is established according to the model-transforming method and closing-vector method. And expressions of its output movement parameters are attained. The output movement characteristic of hybrid-driven five-bar mechanism is imitated and studied. The results show that hybrid-driven five-bar mechanism which its geometry parameters confirmed can accomplish diversiform tasks through changing its input movement rule. Output movement track of hybrid-driven five-bar mechanism changes along with the original position of two input components changing. It indicates hybrid-driven five-bar mechanism can accomplish many group tasks at one time.

scholarly journals Study of a New 5-DOF Parallel Mechanism for Multi-Directional 3D Printing

2020 ◽  
Author(s):  
Yesong Wang ◽  
Changhuai Lyu ◽  
Jiang Liu ◽  
Jinguang Zhang ◽  
Zhixin Jia
Keyword(s):  
3D Printing ◽  
Parallel Mechanism ◽  
Closed Loop ◽  
Three Dimensional ◽  
Line Geometry ◽  
Vector Method ◽  
Grassmann Line Geometry ◽  
Working Performance ◽  
Geometry Method ◽  
Unstable Problem

Abstract This paper first designs a new 5-DOF parallel mechanism with 5PUS-UPU for multi-directional 3D printing, and then analyses its DOF by traditional Grubler-Kutzbach and motion spiral theory. It theoretically shows that the mechanism meets the requirement of 5 dimensions of freedoms including three-dimensional movement and two-dimensional rotation. Basing on this, the real mechanism is built, but unfortunately it is found unstable in some positions. Grassmann line geometry method is applied to analyze its unstable problem caused by singular posture, and then an improving method is put forward to solve it. With the improved mechanism, closed loop vector method is employed to establish the inverse position equation of the parallel mechanism, and kinematics analysis is carried out to get the mapping relationships between position, speed and acceleration of moving and fixed platform, Monte Carlo method is used to analyze the workspace of the mechanism, to explore the influencing factors of workspace, and then to get the better workspace. Finally an experiment is designed to verify the mechanism working performance to satisfy the spatial motion requirements of multi-directional 3D printing.

scholarly journals An Improved Model Predictive Control Method for Three-Port Soft Open Point

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Zhengqi Wang ◽  
Liusen Sheng ◽  
Qunhai Huo ◽  
Sipeng Hao
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Complex Structure ◽  
Prediction Method ◽  
Current Control ◽  
Compensation Method ◽  
Vector Method ◽  
Vector Angle ◽  
Improved Model ◽  
Open Point

Soft open point (SOP) is a key power electronic device to improve the flexibility and stability of the distribution network and is becoming a research hotspot. The traditional double closed-loop control of SOP has a complex structure, difficult process of parameter design, and poor output power quality. To solve these problems, finite control set model predictive control (FCS-MPC) has been adopted. Since FCS-MPC involves a large amount of calculation and experiences delay in current tracking, an improved FCS-MPC with delay compensation is proposed for three-port SOP in this paper to replace the inner loop current control strategy. Improved model predictive control combines the two-step prediction method based on the voltage vector and vector angle compensation method. The vector method is used to construct a mathematical model and a prediction model of three-port SOP. Based on FCS-MPC, the two-step prediction method that takes voltage as the target is used to compensate for the current delay problem, and the amount of calculation is reduced by converting the control target. Meanwhile, the vector angle compensation method is used to compensate the future reference value. Finally, a simulation model is built in MATLAB/Simulink. The simulation results under steady state and dynamic conditions show that the proposed strategy can effectively improve the current delay and reduce the amount of calculation. Furthermore, it has better current tracking accuracy and faster dynamic response speed.

Accuracy analysis and synthesis of asymmetric parallel mechanism based on Sobol-QMC

2020 ◽  
Vol 234 (21) ◽  
pp. 4200-4214
Author(s):  
Mengli Wu ◽  
Xianqu Yue ◽  
Weibin Chen ◽  
Qi Nie ◽  
Yue Zhang
Keyword(s):  
Parallel Mechanism ◽  
Closed Loop ◽  
Jacobian Matrix ◽  
Mapping Function ◽  
Error Modeling ◽  
Accuracy Analysis ◽  
Vector Method ◽  
Evaluation Indexes ◽  
Quasi Monte Carlo ◽  
Analysis And Synthesis

Aiming at the aircraft composite skin grinding, a new three degree-of-freedom (DOF) parallel mechanism with asymmetrical structure (TAM) is proposed to replace manual grinding. The TAM is achieved by integrating one of active limbs into the passive limb while keeping the required DOF unchanged, which is divided into two closed-loop chains: telescopic rod and parallelogram. The inverse kinematics models of the two chains are established according to closed-loop vector method. Thus, the actuation and the constraint Jacobian matrix are obtained. Based on the perturbation principle, the error modeling of the TAM is built. Adopting the constraint Jacobian matrix, 15 uncompensated errors are distinguished from the error model. In order to improve the working accuracy of the TAM, accuracy analysis and synthesis are necessary for all the uncompensated errors. The mapping function reflects the influence of uncompensated errors on the pose accuracy. The global sensitivity evaluation indexes are established by mapping function. Since Sobol sequences are superior in uniformity and convergence, the Quasi-Monte Carlo method based on Sobol sequences (Sobol-QMC) is introduced for sensitivity analysis. Taking the minimum manufacturing and installation costs as the optimization target, the objective function of accuracy synthesis is constructed. Ultimately, the reasonable tolerance zone of each uncompensated error is calculated by genetic algorithm. Simulation is performed by Sobol-QMC to verify the rationality of the optimization. The results show the probability is above 97% where most pose errors are in [[Formula: see text], [Formula: see text]] within the workspace. Therefore, accuracy synthesis is correct and practical.

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