Research on Contouring Control of Dual Linear Motors

2014 ◽  
Vol 945-949 ◽  
pp. 1661-1664
Author(s):  
Li Mei Wang ◽  
Hao Zheng
Keyword(s):  
Tracking Error ◽  
Iterative Learning ◽  
Contour Error ◽  
Direct Drive ◽  
Linear Motors ◽  
Load Disturbance ◽  
Contouring Control ◽  
Contour Accuracy ◽  
Velocity Mismatch ◽  
Control Accuracy

In dual-axis contouring motion, contouring error is a more important performance index than tracking error. Considering direct drive XY table control accuracy, the influence of load disturbance and the velocity mismatch between X and Y axis are great. As a result, the position tracking iterative learning controller based on DOB controller is adopted at single axis, it can overcome the influence of the load disturbance, and ensure the robustness of the system; For the velocity mismatch between X and Y axis, a control strategy based on hybrid error iterative learning control (HILC) and the real-time contour error model was proposed. Simulation results show that the designed control system of XY table has strong robustness, high contour accuracy and simple structure.

Iterative Learning Cross-Coupled Control for XY Table Based on Real-Time Contour Error Estimation

2011 ◽  
Vol 383-390 ◽  
pp. 7054-7059 ◽  
Author(s):  
Li Mei Wang ◽  
Qi Yang ◽  
Yi Biao Sun ◽  
Chun Fang Liu
Keyword(s):  
Real Time ◽  
External Disturbance ◽  
Iterative Learning ◽  
Free Form ◽  
Contour Error ◽  
Dynamic Matching ◽  
Linear Motors ◽  
Control Scheme ◽  
Table Model ◽  
Estimate Method

The contour accuracy of XY table directly driven by two linear motors was influenced by the complicated reel-time contour error model of free-form curves, uncertainty external disturbance and dynamic matching between X axis and Y axis. To establish XY table model that easily calculated and suitable for free-form curves, real-time contour error estimate method was adopted. In order to reduce uncertainty external disturbance and dynamic matching between X axis and Y axis, the iterative learning cross-coupled controller (ILCCC) was designed for current compensation on X axis and Y axis. Simulation results show that the control scheme can enhance the robustness of the system, and effectively improve the XY table of contour precision.

Contour Tracking Control for Direct Drive X-Y Table Based on Equivalent Errors Model

2014 ◽  
Vol 945-949 ◽  
pp. 1673-1676
Author(s):  
Zhi Tao Wu ◽  
Jian Ying Xu
Keyword(s):  
Tracking Control ◽  
Contour Error ◽  
Contour Tracking ◽  
Direct Drive ◽  
Tracking Accuracy ◽  
Optimal Position ◽  
Nonlinear Disturbances ◽  
Error Dynamic ◽  
Position Controller ◽  
Contour Accuracy

For the contour accuracy of direct drive X-Y servo system is susceptible to changes of the load parameters and nonlinear disturbances including the friction , A quadratic optimal position controller with sliding contour tracking controller based on equivalent errors model is proposed to improve contour tracking performance and the robustness. The position controller is designed by the factorization of quadratic optimization on frequency domain. Based on Equivalent Errors model including the equivalent contour error and tangential error, the contour tracking problem is converted to the stabilization of error dynamic system. Simulation and experimental results show that the effects of nonlinear disturbances are reduced effectively and the designed controller has high contour tracking accuracy and strong robustness.

Performance improvement of bilateral control systems using derivative of force

Robotica ◽  
2018 ◽  
Vol 36 (11) ◽  
pp. 1627-1640 ◽  
Author(s):  
Eray A. Baran ◽  
Tarik Uzunovic ◽  
Asif Sabanovic
Keyword(s):  
Position Control ◽  
Control Structure ◽  
Controller Design ◽  
Reaction Force ◽  
Tracking Error ◽  
Direct Drive ◽  
Bilateral Control ◽  
Linear Motors ◽  
Force Signal ◽  
Hard Contact

SUMMARYThis paper proposes a bilateral control structure with a realization of the force derivative in the control loop. Due to the inherent noisy nature of the force signal, most teleoperation schemes can make use of only a proportional (P) control structure in the force channel of the bilateral controllers. In the proposed scheme, an α–β–γ filter is designed to smoothly differentiate the force signal obtained from a reaction force observer integrated to both of the master and slave plants. The differentiated force signal is then used in a proportional-derivative (PD) force controller working together with a disturbance observer. In order to design the overall bilateral controller, an environment model based on pure spring structure is assumed. The controller is designed to enforce an exponentially decaying tracking error for both position and force signals. With the presented controller design approach, one can independently tune the controller gains of the force and the position control channels. The proposed approach is experimentally tested in a platform consisted of direct drive linear motors. As illustrated by the experiment results, the contribution of the PD control in the force channel improves the teleoperation performance especially under hard-contact motion scenarios by attenuating the oscillations, hence, improving the transparency when compared to the structures using only a P force control.

scholarly journals Adaptive speed control method for electromagnetic direct drive vehicle robot driver based on fuzzy logic

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1344-1353 ◽  
Author(s):  
Gang Chen ◽  
Weigong Zhang ◽  
Xu Li ◽  
Bing Yu
Keyword(s):  
Fuzzy Logic ◽  
Control Method ◽  
Tracking Error ◽  
Speed Control ◽  
System Structure ◽  
Direct Drive ◽  
Test Standards ◽  
Speed Controller ◽  
Fuzzy Neural ◽  
Vehicle Test

To solve the shortcomings of existing control methods for an electromagnetic direct drive vehicle robot driver, including large speed tracking error and large mileage deviation, a new adaptive speed control method for the electromagnetic direct drive vehicle robot driver based on fuzzy logic is proposed in this paper. The electromagnetic direct drive vehicle robot driver adapts an electromagnetic linear motor as its drive mechanism. The control system structure is designed. The coordinated controller for multiple manipulators is presented. Moreover, an adaptive speed controller for the electromagnetic direct drive vehicle robot driver is proposed to achieve the accurate tracking of desired speed. Experiments are conducted using a Ford FOCUS car. Performances of the proposed method, proportional–integral–derivative, and fuzzy neural network are compared and analyzed. Experimental results demonstrate that the proposed control method can accurately track the target speed, and it can inhabit the change of speed caused by interference under different test conditions, and it has small mileage deviation, which can meet the requirements of national vehicle test standards.

Iterative learning control algorithm for sensor fault nonlinear systems

2020 ◽  
pp. 1-8
Author(s):  
Zimian Lan
Keyword(s):  
Nonlinear Systems ◽  
Iterative Learning Control ◽  
Control Algorithm ◽  
Tracking Error ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Sensor Fault ◽  
Initial State ◽  
Control Gain

In this paper, we propose a new iterative learning control algorithm for sensor faults in nonlinear systems. The algorithm does not depend on the initial value of the system and is combined with the open-loop D-type iterative learning law. We design a period that shortens as the number of iterations increases. During this period, the controller corrects the state deviation, so that the system tracking error converges to the boundary unrelated to the initial state error, which is determined only by the system’s uncertainty and interference. Furthermore, based on the λ norm theory, the appropriate control gain is selected to suppress the tracking error caused by the sensor fault, and the uniform convergence of the control algorithm and the boundedness of the error are proved. The simulation results of the speed control of the injection molding machine system verify the effectiveness of the algorithm.

Iterative learning algorithm with a quadratic criterion for linear time-varying systems

2002 ◽  
Vol 216 (3) ◽  
pp. 309-316 ◽  
Author(s):  
S N Huang ◽  
K K Tan ◽  
T H Lee
Keyword(s):  
Learning Algorithm ◽  
Linear Time ◽  
Tracking Error ◽  
Iterative Learning ◽  
Tracking Performance ◽  
Time Varying ◽  
Control Scheme ◽  
Time Varying Systems ◽  
Simulation Results ◽  
Learning Law

A novel iterative learning controller for linear time-varying systems is developed. The learning law is derived on the basis of a quadratic criterion. This control scheme does not include package information. The advantage of the proposed learning law is that the convergence is guaranteed without the need for empirical choice of parameters. Furthermore, the tracking error on the final iteration will be a class K function of the bounds on the uncertainties. Finally, simulation results reveal that the proposed control has a good setpoint tracking performance.

scholarly journals Cross-Coupled Contouring Control of Multi-DOF Robotic Manipulator

2021 ◽  
Author(s):  
Puren Ouyang ◽  
Yuqi Hu ◽  
Wenhui Yue ◽  
Deshun Liu
Keyword(s):  
Control System ◽  
Translational Motion ◽  
Contour Error ◽  
Control Law ◽  
Contour Tracking ◽  
Pd Control ◽  
Tracking Errors ◽  
End Effector ◽  
Joint Level ◽  
Contouring Control

Reduction of contour error is a very important issue for high precise contour tracking applications, and many control systems were proposed to deal with contour tracking problems for two/three axial translational motion systems. However, there is no research on cross-coupled contour tracking control for serial multi-DOF robot manipulators. In this paper, the contouring control of multi-DOF serial manipulators is developed for the first time and a new cross-coupled PD (CC-PD) control law is proposed, based on contour errors of the end-effector and tracking errors of the joints. It is a combination of PD control for trajectory tracking at joint level and PD control for contour tracking at the end-effector level. The contour error of the end-effector is transformed to the equivalent tracking errors of the joints using the Jacobian regulation, and the CC-PD control law is implemented in the joint level. Stability analysis of the proposed CC-PD control system is conducted using the Lyapunov method, followed by some simulation studies for linear and nonlinear contour tracking to verify the effectiveness of the proposed CC-PD control system.

Improving Contour Accuracy of Machine Tools Using an Integral-Gain Scheduler

2005 ◽  
Vol 219 (7) ◽  
pp. 511-518 ◽  
Author(s):  
R C Ko ◽  
M C Good
Keyword(s):  
Machine Tools ◽  
High Performance ◽  
Pulse Width Modulation ◽  
Tracking Error ◽  
Contour Error ◽  
Current Loop ◽  
Pwm Inverter ◽  
Current Controller ◽  
Reversal Error ◽  
Grinding Machine

In high-precision machine tools, contour error at axis reversal can significantly reduce the quality of products. Resulting from non-linear friction behaviour, the reversal error is traditionally handled by the velocity controller, which highly relies on a high-performance current servo. However, the widely employed pulse width modulation (PWM) inverter in the power stage of the current servo operates with a severe non-linearity known as deadband. The deadband effect degrades the current-loop tracking performance and consequently hinders the velocity controller in responding to friction disturbances. The result is a significant and oscillatory tracking error, or contour error in a multiaxis system. Unlike other approaches where the deadband is compensated via measurement or estimation, a control system approach is proposed in this paper where the deadband is treated as a voltage perturbation in the current loop. The proposed scheme incorporates a feedforward signal from the current command and schedules the integral action in the current controller accordingly. The proposed scheme was implemented in digital servo drives of a commercial grinding machine. Experiments show that the proposed scheme is an effective and practical solution for this type of problem.

Arc Linear Motors for Direct Drive Robots: Galileo Sphere

2008 ◽  
Author(s):  
Claudio Bianchini ◽  
Fabio Immovilli ◽  
A. Bellini ◽  
Paolo Mignano
Keyword(s):  
Direct Drive ◽  
Linear Motors
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