Tracking Accuracy Analysis of a Planar Flexible Manipulator With Lubricated Joint and Interval Uncertainty

2016 ◽  
Vol 11 (5) ◽  
Author(s):  
Dongyang Sun
Keyword(s):  
Interval Uncertainty ◽  
Flexible Manipulator ◽  
Accuracy Analysis ◽  
Tracking Accuracy ◽  
Element Discretization ◽  
Revolute Joint ◽  
Interval Analysis Method ◽  
Self Tuning ◽  
The Stability ◽  
Control Accuracy

A method for trajectory tracking accuracy analysis of a two-link flexible manipulator with lubricated revolute joint involving interval uncertainty is presented. In this method, first, fuzzy self-tuning proportion integration differentiation (PID) control is applied to track the desired tip trajectory of the manipulator. The absolute nodal coordinate formulation (ANCF) is employed for the finite element discretization of the flexible manipulator. And lubricated revolute joint is modeled based on the infinitely short journal bearing with Gümbel conditions. Second, uncertainty of clearance size is considered, and interval analysis method is applied. Numerical simulation is posted to investigate the cushioning effect of lubricants on the clearance and influence of uncertainty on control accuracy of the manipulator. The results show that the lubricants can improve the stability of motion and operation precision of the manipulator; however, uncertainty of the manipulator may reduce the control accuracy of the manipulator.

Controlled Freezing of Nonideal Solutions With Application to Cryosurgical Processes

1991 ◽  
Vol 113 (4) ◽  
pp. 430-437 ◽  
Author(s):  
H. M. Budman ◽  
J. Dayan ◽  
A. Shitzer
Keyword(s):  
Cooling Rate ◽  
Freezing Process ◽  
Data Sets ◽  
Tracking Accuracy ◽  
Loop Control ◽  
Set Point ◽  
New Device ◽  
Loop Control System ◽  
The Stability ◽  
Controlled Freezing

Success of a cryosurgical procedure, i.e., maximal cell destruction, requires that the cooling rate be controlled during the freezing process. Standard cryosurgical devices are not usually designed to perform the required controlled process. In this study, a new cryosurgical device was developed which facilitates the achievement of a specified cooling rate during freezing by accurately controlling the probe temperature variation with time. The new device has been experimentally tested by applying it to an aqueous solution of mashed potatoes. The temperature field in the freezing medium, whose thermal properties are similar to those of biological tissue, was measured. The cryoprobe temperature was controlled according to a desired time varying profile which was assumed to maximize necrosis. The tracking accuracy and the stability of the closed loop control system were investigated. It was found that for most of the time the tracking accuracy was excellent and the error between the measured probe temperature and the desired set point is within ±0.4°C. However, noticeable deviations from the set point occurred due to the supercooling phenomenon or due to the instability of the liquid nitrogen boiling regime in the cryoprobe. The experimental results were compared to those obtained by a finite elements program and very good agreement was obtained. The deviation between the two data sets seems to be mainly due to errors in positioning of the thermocouple junctions in the medium.

scholarly journals Design of Augmented Nonlinear PD Controller of Delta/Par4-Like Robot

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Amjad J. Humaidi ◽  
Ahmed Ibraheem Abdulkareem
Keyword(s):  
Trajectory Tracking ◽  
Lyapunov Method ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Pd Controller ◽  
Comparison Study ◽  
Tracking Accuracy ◽  
Control Schemes ◽  
The Stability ◽  
Made In

This work presents the design of two control schemes for a Delta/Par4-like parallel robot: augmented PD (APD) controller and augmented nonlinear PD (ANPD) controller. The stability of parallel robot based on nonlinear PD controller has been analyzed and proved based on Lyapunov method. A comparison study between APD and ANPD controllers has been made in terms of performance and accuracy improvement of trajectory tracking. Also, another comparison study has been presented between augmented nonlinear PD (ANPD) controller and nonaugmented nonlinear PD (NANPD) controller in order to show the enhancement of introducing the augmented structure on dynamic performance and trajectory tracking accuracy. The effectiveness of augmented PD controllers (APD and ANPD) and nonaugmented nonlinear PD (NANPD) controller for the considered parallel robot are verified via simulation within the MATLAB environment.

Time Delay Instabilities in Large Order Systems With Controlled Follower Forces

1972 ◽  
Vol 94 (4) ◽  
pp. 330-334 ◽  
Author(s):  
G. Y. Matsumoto ◽  
C. D. Mote
Keyword(s):  
Time Delay ◽  
Decomposition Method ◽  
Control Mechanism ◽  
Continuous System ◽  
Sample Problem ◽  
Finite Element Discretization ◽  
Element Discretization ◽  
Thrust Vector ◽  
Nonconservative Loading ◽  
The Stability

An extension of the τ-decomposition method is used to predict the stability of a continuous system subjected to nonconservative loading. The technique is implemented through Ritz-finite element discretization. The stability of a flexible rocket (or beam) with a controlled orientation thrust vector (or follower force) is examined with respect to finite time delay in the control mechanism. Higher mode instabilities in the rocket are observed in the sample problem and are treated satisfactorily in the technique. Both buckling and flutter conditions are determined from eigenvalue trajectories in the complex plane.

On Self-Tuning Control of Nonminimum Phase Discrete-Time Systems Using Approximate Inverse Systems

1993 ◽  
Vol 115 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Takashi Yahagi ◽  
Jianming Lu
Keyword(s):  
Discrete Time ◽  
Stochastic Systems ◽  
Output Data ◽  
Approximate Inverse ◽  
Nonminimum Phase ◽  
Discrete Time Systems ◽  
Inverse Systems ◽  
Self Tuning ◽  
The Stability ◽  
Time Systems

This paper presents a new method for self-tuning control of nonminimum phase discrete-time stochastic systems using approximate inverse systems obtained from the least-squares approximation. We show how unstable pole-zero cancellations can be avoided, and that this method has the advantage of being able to determine an approximate inverse system independently of the plant zeros. The proposed scheme uses only the available input and output data and the stability using approximate inverse systems is analyzed. Finally, the results of computer simulation are presented to show the effectiveness of the proposed method.

scholarly journals Stability of PDF Controller With Stick-Slip Friction Device

1997 ◽  
Vol 119 (3) ◽  
pp. 486-490 ◽  
Author(s):  
Jia-Yush Yen ◽  
Chih-Jung Huang ◽  
Shu-Shung Lu
Keyword(s):  
Control Algorithm ◽  
Controller Design ◽  
System Model ◽  
Pole Placement ◽  
Order System ◽  
Stick Slip ◽  
Precision Control ◽  
Experimental Works ◽  
The Stability ◽  
Control Accuracy

This paper presents the precision control of drive devices with significant stick-slip friction. The controller design follows the Pseudo-Derivative Feedback (PDF) control algorithm. Using the second order system model, the PDF controller offers arbitrary pole placement. In this paper, the stability proof for the controller with stick-slip friction is presented. On the basis of this proof, the stability criteria are derived. The paper also includes both the computer simulation and the experimental works to confirm the theoretical result. The experiments conducted on a Traction Type Drive Device (TTDD) shows that control accuracy of as high as ±1 arc – second is achieved.

scholarly journals Study on Acc/Dec Algorithm Based on Piecewise Polynomial in CNC

2011 ◽  
Vol 2-3 ◽  
pp. 43-47 ◽  
Author(s):  
Guo Shun Ji ◽  
Zhi Ping Chen ◽  
Ju Yong Zhang ◽  
Wei Liu
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Polynomial Function ◽  
Tracking Accuracy ◽  
Feedrate Planning ◽  
Smooth Motion ◽  
Planning Algorithm ◽  
S Curve ◽  
The Stability ◽  
Motion Profile

In order to improve the stability of feed movement in high speed CNC system, the feedrate planning algorithm based on piece-wise polynomial function was proposed. The flexible transition of feedrate was realized through maintaining linear continuous jerk. The principle of the proposed algorithm was introduced and the method to generate smooth motion profile based on the proposed algorithm was presented. The rapidity, stability and tracking accuracy of the feedrate planning algorithm to linearity, S curve and the proposed one were analyzed. The proposed algorithm is simple and it can be applied in acceleration/deceleration before interpolation in high speed feed movement to improve the stability of it. The proposed algorithm was applied in multi-contour high speed processing and the result indicated that it could improve the stability of large-scale parts motion.

Fuzzy PID Control and Simulation of Wind Power Generation Yaw System

2014 ◽  
Vol 953-954 ◽  
pp. 353-356 ◽  
Author(s):  
Fan Yang ◽  
Tong Yang ◽  
Xiao Hong Yang
Keyword(s):  
Pid Control ◽  
Pid Controller ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Fuzzy Pid Controller ◽  
Time Performance ◽  
System A ◽  
Self Tuning ◽  
Simulation Results ◽  
The Stability

Aimed at the high inertia and non-linear characteristics of yaw system, a parameter self –tuning fuzzy PID controller is designed. The controller can adjust the PID parameters based on the wind direction variation, and make the turbines track the coming wind timely to obtain maximum power output. Simulation results show that the controller has good real-time performance and robustness compared with the traditional PID control. It can lower the fluctuation and overshoot, and improve the stability of the yaw system significantly.

A Robust Aerodynamic Optimization Design for Airfoil Based on Interval Uncertainty Analysis Method

2019 ◽  
Author(s):  
Xin Song ◽  
Guannan Zheng ◽  
Guowei Yang
Keyword(s):  
Robust Optimization ◽  
Interval Analysis ◽  
Optimization Design ◽  
Aerodynamic Force ◽  
Interval Uncertainty ◽  
Upper And Lower Bounds ◽  
Analysis Method ◽  
Geometric Uncertainties ◽  
Interval Analysis Method ◽  
Robust Optimization Design

Abstract Uncertainties will make aircraft deviate from the designed condition, resulting in the decrease in aerodynamic performance and even destruction. This paper presents a fast nonlinear interval analysis method considering geometric uncertainties. DFFD method is used to parameterize the airfoil shape, and the Kriging model for aerodynamic force and uncertainty variables is optimized by PSO algorithm to find the upper and lower bounds of the objective interval. The effects of geometric uncertainties on NACA0012 airfoil are analyzed using the above method. And then, a robust optimization design method is established based on the interval analysis method. FFD method is used to produce the deterministic design variables and the order relation of interval number is employed to transform the uncertain optimization to deterministic multi-objective optimization which is solved by MOPSO based on Pareto entropy. The robust optimization design is implemented for the symmetrical airfoil with the drag objective under geometric uncertainties and thickness constraint, and the results are compared with the deterministic optimization to validate the effectiveness of the developed method.

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