Optimal Feed-Forward Digital Tracking Controller Design

1994 ◽  
Vol 116 (4) ◽  
pp. 583-592 ◽  
Author(s):  
Tsu-Chin Tsao
Keyword(s):  
Controller Design ◽  
Reference Model ◽  
Phase Error ◽  
Tracking Error ◽  
Reference Signal ◽  
Tracking Performance ◽  
Design Parameters ◽  
Matching Problem ◽  
Feed Forward ◽  
Tracking Controller

This paper presents an approach for optimal digital feed-forward tracking controller design. The tracking problem is formulated as a model matching problem, in which the distance between a specified tracking reference model and the achievable tracking performance by feedforward compensation is minimized. Desired input/output characteristics, finite length preview action, tracking of specific classes of constrained signals, time domain reference signal velocity or acceleration bound, and frequency domain weighting are conveniently incorporated in the proposed controller design and their roles in tracking performance are discussed. The tracking error bound is also explicitly expressed in terms of the controller design parameters. An l1 norm optimal tracking controller is proposed as a solution to the mechanical tolerance control problem. A motion control example illustrates the design approach and several aspects of the resulting optimal feedforward controller, including the optimality of the zero phase error tracking controller.

Closed-Loop Identification and Composed Controller Design for Precise Machining

2010 ◽  
Vol 97-101 ◽  
pp. 3139-3145 ◽  
Author(s):  
Jun Sheng ◽  
Jian Gang Li ◽  
Lei Zhou
Keyword(s):  
Controller Design ◽  
Phase Error ◽  
Control Plant ◽  
Feed Forward ◽  
Tracking Controller ◽  
Position Controller ◽  
Closed Loop Identification ◽  
Derivative Filter ◽  
Feed Forward Controller ◽  
Zero Phase

For a class of three-loop architecture motion control system, two-stage close-loop identification is introduced to estimate the control plant and thus to tune the velocity controller. Based on the estimated model, PID position controller with derivative filter is proposed using pole-zero cancellation and pole assignment. Feed-forward compensators such as Velocity and Acceleration Feed-forward Controller (VAFC), Zero Phase Error Tracking Controller (ZPETC), Zero Magnitude Error Tracking controller (ZMETC) are introduced as well, and their effects are compared.

scholarly journals Modeling and adaptive tracking for stochastic nonholonomic constrained mechanical systems

2016 ◽  
Vol 21 (2) ◽  
pp. 166-184 ◽  
Author(s):  
Zhongcai Zhang ◽  
Yuqiang Wu
Keyword(s):  
Dynamic Model ◽  
Controller Design ◽  
Internal State ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Design Parameters ◽  
Unknown Parameters ◽  
Constrained Mechanical Systems ◽  
Adaptive Tracking ◽  
Tracking Controller

This paper is devoted to the problem of modeling and trajectory tracking for stochastic nonholonomic dynamic systems in the presence of unknown parameters. Prior to tracking controller design, the rigorous derivation of stochastic nonholonomic dynamic model is given. By reasonably introducing so-called internal state vector, a reduced dynamic model, which is suitable for control design, is proposed. Based on the backstepping technique in vector form, an adaptive tracking controller is then derived, guaranteeing that the mean square of the tracking error converges to an arbitrarily small neighborhood of zero by tuning design parameters. The efficiency of the controller is demonstrated by a mechanics system: a vertical mobile wheel in random vibration environment.

Extended State Observer Based Controller Design for the Green Bank Telescope Servo System

2015 ◽  
Author(s):  
Trupti Ranka ◽  
Mario Garcia-Sanz ◽  
John M. Ford
Keyword(s):  
Disturbance Rejection ◽  
Pid Controller ◽  
Controller Design ◽  
Tracking Error ◽  
State Observer ◽  
Extended State Observer ◽  
Tracking Performance ◽  
Extended State ◽  
External Disturbances ◽  
Green Bank Telescope

The Green Bank Telescope is a large flexible structure, requiring rms tracking error ≤ 3 arcseconds against internal and external disturbances. We design an extended state observer (ESO) based controller in various configurations to improve tracking performance and increase disturbance rejection. The controllers are simulated with an experimentally validated model of the GBT. Through the simulations, the response of ESO based controllers and legacy PID controller are compared using time and frequency domain responses. We show that the ESO based controller when implemented in both position and velocity loop can give significant improvement in tracking performance and better disturbance rejection without increase in controller output.

Precision motion control of permanent magnet linear synchronous motor servo system based on an integrated controller with inertia variation compensation

2012 ◽  
Vol 227 (7) ◽  
pp. 1481-1494 ◽  
Author(s):  
Zhijun Li ◽  
Chengying Liu ◽  
Fanwei Meng ◽  
Kai Zhou
Keyword(s):  
Permanent Magnet ◽  
Motion Control ◽  
Disturbance Observer ◽  
Phase Error ◽  
Servo System ◽  
Tracking Performance ◽  
Tracking Controller ◽  
Integrated Controller ◽  
Feed Forward Controller ◽  
Zero Phase

To achieve high robustness and precise motion control of permanent magnet linear synchronous motor servo system, an integrated controller is presented, including a velocity feed forward controller, a zero phase error tracking controller, a disturbance observer and inertia variation compensator. The velocity feed forward controller and the zero phase error tracking controller are included to improve tracking performance and the disturbance observer is involved to enhance disturbance rejection. However, both the zero phase error tracking controller and the disturbance observer are sensitive to inertia variation which often occurs in servo systems. So, an inertia compensator, which consists of a perfect tracking controller for the current loop and a compensation gain, is proposed to retain tracking performance. Detailed experiments are conducted on a PMLSM servo system to confirm the effectiveness of the integrated controller.

scholarly journals A Novel Position Domain Controller For Contour Tracking Performance Improvement

2021 ◽  
Author(s):  
Truong Dam
Keyword(s):  
Time Domain ◽  
Phase Error ◽  
Common Factor ◽  
Tracking Error ◽  
Numerical Control ◽  
Tracking Performance ◽  
Contour Error ◽  
Contour Tracking ◽  
Cnc Machine ◽  
Equivalent Time

A common problem with modern manufacturing processes that utilize high feed-rate machining is how to accurately track a given contour for the tool center point (TCP) of a system. Various methods have been developed to increase axial tracking performance and contouring performance of computerized numerical control (CNC) machines. These include: high gain feedback controllers, feedforward controllers, zero phase error tracking controllers (ZPETC), cross-coupled control (CCC), and iterative learning control to mention a few. The common factor amongst these methods is that they are all based in time domain. This thesis will propose a new control law based in position domain applied to contour tracking control of a CNC machine. The goal of this developed controller is to improve the overall tracking and contouring performance of a CNC system. The idea behind a position domain control involves transforming the dynamics of a system from time domain into position domain through a one-to-one mapping. In the position domain system control, the motion of one of the axis is used as an independent reference by sampling equidistantly to control the remaining axes according to the contouring requirements. The overall contour error in a position domain controller should be lower relative to an equivalent time domain controller since there will be a zero tracking error from the reference motion. The stability of the proposed position domain control is proven through the Lyapunov method. Simulations with linear and nonlinear TCP contours using the proposed position domain controller and an equivalent time domain controller indicate that the proposed position domain control can improve tracking and contouring performance. In addition, a position domain controller with cross-coupled control was also proposed to further improve contour performance.

scholarly journals Bounded Analysis and Practical Tracking Control of Complex Stochastic Nonlinear Systems with Unknown Control Coefficients

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Long-Chuan Guo ◽  
Xiang-Kun Fang
Keyword(s):  
Nonlinear Systems ◽  
Tracking Error ◽  
Upper And Lower Bounds ◽  
Design Parameters ◽  
Stochastic Nonlinear Systems ◽  
Tracking Controller ◽  
Unknown Control Coefficients ◽  
Unknown Control ◽  
Theoretical Results ◽  
Control Coefficients

This paper mainly focuses on the output practical tracking controller design for a class of complex stochastic nonlinear systems with unknown control coefficients. In the existing research results, most of the complex systems are controlled in a certain direction, which leads to the disconnection between theoretical results and practical applications. The authors introduce unknown control coefficients, and the values of the upper and lower bounds of the control coefficients are generalized by constants to allow arbitrary values to be arbitrarily large or arbitrarily small. In the control design program, the design problem of the controller is transformed into a parameter construction problem by introducing appropriate coordinate transformation. Moreover, we construct an output feedback practical tracking controller based on the dynamic and static phase combined by Ito stochastic differential theory and selection of appropriate design parameters, ensuring that the system tracking error can be made arbitrarily small after some large enough time. Finally, a simulation example is provided to illustrate the efficiency of the theoretical results.

scholarly journals Adaptive Output Feedback Tracking Controller Design of Stochastic Nonlinear Systems with Parameter Uncertainty for Polynomial Function Growth Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Long-Chuan Guo
Keyword(s):  
Nonlinear Systems ◽  
Output Feedback ◽  
Controller Design ◽  
Polynomial Function ◽  
Tracking Error ◽  
Parametric Uncertainty ◽  
Growth Conditions ◽  
Stochastic Nonlinear Systems ◽  
Tracking Controller ◽  
Feedback Tracking

This paper mainly focuses on output feedback practical tracking controller design for stochastic nonlinear systems with polynomial function growth conditions. Mostly, there are some studies on output feedback tracking control problem for general nonlinear systems with parametric certainty in existing achievements. Moreover, we extend it to stochastic nonlinear systems with parametric uncertainty and system nonlinear terms are assumed to satisfy polynomial function growth conditions which are more relaxed than linear growth conditions or power growth conditions. Due to the presence of unknown parametric uncertainty, an output feedback practical tracking controller with dynamically updated gains is constructed explicitly so that all the states of the closed-loop systems are globally bounded and the tracking error belongs to arbitrarily small interval after some positive finite time. An example illustrates the efficiency of the theoretical results.

Sine phase compensation combining an amplitude phase controller and a discrete feed-forward compensator for electro-hydraulic shaking tables

2017 ◽  
Vol 40 (11) ◽  
pp. 3377-3389 ◽  
Author(s):  
Ge Li ◽  
Gang Shen ◽  
Zhen-Cai Zhu ◽  
Xiang Li ◽  
Wan-Shun Zang
Keyword(s):  
Control Strategy ◽  
Phase Error ◽  
Phase Delay ◽  
Shaking Table ◽  
Response Signal ◽  
Feed Forward ◽  
Amplitude Attenuation ◽  
Tracking Controller ◽  
Phase Deviation ◽  
Zero Phase

This article presents a novel control strategy on an electro-hydraulic shaking table under the acceleration control combining an amplitude phase controller and a zero phase error tracking controller with a discrete feed-forward compensator. Because of the electro-hydraulic system’s nonlinearity, phase delay and amplitude attenuation exist in the acceleration response signal inevitably when the electro-hydraulic shaking table system is excited by a sine vibration signal. Moreover, the phase delay of the electro-hydraulic shaking table is composed of phase deviation and actuator delay. For improving the acceleration tracking accuracy, an amplitude phase controller is employed to compensate the phase deviation and amplitude attenuation by introducing weights to adjust the reference signal. Meanwhile, the discrete feed-forward compensator is applied to compensate the actuator delay. As an offline compensator, the zero phase error tracking controller is employed to compensate the phase delay of the response signal and improve the convergence speed of the proposed controller. Overall, the proposed control strategy combines the merits of these three controllers with better tracking performance demonstrated by simulation and experimental results.

Feedforward Tracking Controller Design Based on the Identification of Low Frequency Dynamics

1993 ◽  
Vol 115 (3) ◽  
pp. 348-356 ◽  
Author(s):  
E. D. Tung ◽  
M. Tomizuka
Keyword(s):  
High Speed ◽  
Linear Models ◽  
Controller Design ◽  
Phase Error ◽  
Low Frequency ◽  
Reference Trajectory ◽  
Accurate Identification ◽  
Tracking Controller ◽  
Feed Drive System ◽  
Zero Phase

Several methodologies are proposed for identifying the dynamics of a machine tool feed drive system in the low frequency region. An accurate identification is necessary for the design of a feedforward tracking controller, which achieves unity gain and zero phase shift for the overall system in the relevant frequency band. In machine tools and other mechanical systems, the spectrum of the reference trajectory is composed of low frequency signals. Standard least squares fits are shown to heavily penalize high frequency misfit. Linear models described by the output-error (OE) and Autoregressive Moving Average with eXogenous Input (ARMAX) models display better closeness-of-fit properties at low frequency. Based on the identification, a feedforward compensator is designed using the Zero Phase Error Tracking Controller (ZPETC). The feedforward compensator is experimentally shown to achieve near-perfect tracking and contouring of high-speed trajectories on a machining center X-Y bed.

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