Synchronization of Two Motion Control Axes Under Adaptive Feedforward Control

1992 ◽  
Vol 114 (2) ◽  
pp. 196-203 ◽  
Author(s):  
Masayoshi Tomizuka ◽  
Jwu-Sheng Hu ◽  
Tsu-Chih Chiu ◽  
Takuya Kamano
Keyword(s):  
Motion Control ◽  
Time Domain ◽  
Adaptive Systems ◽  
Feedforward Control ◽  
Synchronization Error ◽  
Adaptive Synchronization ◽  
Motion Error ◽  
Feedforward Controller ◽  
The Difference ◽  
Adaptive Feedforward

In this paper, motion synchronization of two d-c motors, or motion control axes, under adaptive feedforward control is considered. The adaptive feedforward control system for each axis consists of a proportional feedback controller, an adaptive disturbance compensator and an adaptive feedforward controller. If the two adaptive systems are left uncoupled, a disturbance input applied to one of the two axes will cause a motion error in the disturbed axis only, and the error becomes the synchronization error. To achieve a better synchronization, a coupling controller, which responds to the synchronization error, i.e., the difference between the two motion errors, is introduced. In this case, when a disturbance input is applied to one axis, the motion errors appear in the undisturbed axis as well as in the disturbed axis. The motion error in the undisturbed axis is introduced by the coupling controller and the adaptive feedforward controller. The adaptive synchronization problem is formulated and analyzed in the continuous time domain first, and then in the discrete time domain. Stability conditions are obtained. Effectiveness of the adaptive synchronization controller is demonstrated by simulation.

scholarly journals Adaptive Feedforward Control of a Pressure Compensated Differential Cylinder

2020 ◽  
Vol 10 (21) ◽  
pp. 7847
Author(s):  
Konrad Johan Jensen ◽  
Morten Kjeld Ebbesen ◽  
Michael Rygaard Hansen
Keyword(s):  
Control System ◽  
Root Mean Square ◽  
Motion Control ◽  
Experimental Verification ◽  
Feedforward Control ◽  
Position Error ◽  
Mean Square ◽  
Model Uncertainties ◽  
Feedforward Controller ◽  
Adaptive Feedforward

This paper presents the design, simulation and experimental verification of adaptive feedforward motion control for a hydraulic differential cylinder. The proposed solution is implemented on a hydraulic loader crane. Based on common adaptation methods, a typical electro-hydraulic motion control system has been extended with a novel adaptive feedforward controller that has two separate feedforward states, i.e, one for each direction of motion. Simulations show convergence of the feedforward states, as well as 23% reduction in root mean square (RMS) cylinder position error compared to a fixed gain feedforward controller. The experiments show an even more pronounced advantage of the proposed controller, with an 80% reduction in RMS cylinder position error, and that the separate feedforward states are able to adapt to model uncertainties in both directions of motion.

Adaptive Synchronization Control Design for High-Speed Magnetic Bearings

1995 ◽  
Author(s):  
Li-Farn Yang ◽  
Jeen-Gwo Tsao
Keyword(s):  
Disturbance Rejection ◽  
High Speed ◽  
Feedforward Control ◽  
Rotating Disk ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Adaptive Synchronization ◽  
Synchronization Control ◽  
Plant Variation ◽  
Adaptive Feedforward

Abstract The performance of actively controlled magnetic bearings is greatly degraded if subjected to unpredictable disturbances or system dynamic variations. This paper present an adaptive synchronization control on a magnetically suspended rotor system for disturbance rejection and plant variation compensation. The rotor system consists of a rotating disk mounted on a shaft which is actively positioned in the radial directions via two magnetic bearings at both ends. Under the synchronizing control, four displacements of shaft along bearing axes are coordinated such that the disturbed displacement can promptly be recovered with those undisturbed in a complementary way. Such motion synchronization requires strict regulation and adaptation through four local controllers with an adaptive feedforward control scheme. The local controllers can be linked by the coupling law, in which an error along one bearing axis can affect overall control loop of four axes. Two control algorithms are developed under the biaxial and quadaxial synchronization conditions, and their adaptation laws are optimized in an attempt to minimize the adaptation errors. Simulations of disturbance rejection responses will also be presented.

scholarly journals Adaptive Feedforward Control for Gust-Induced Aeroelastic Vibrations

Aerospace ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 86 ◽  
Author(s):  
Yongzhi Wang ◽  
Andrea Da Ronch ◽  
Maryam Ghandchi Tehrani
Keyword(s):  
Feedforward Control ◽  
Single Input Single Output ◽  
Output Controller ◽  
Single Output ◽  
Aeroelastic Model ◽  
Feedforward Controller ◽  
The Time Domain ◽  
Adaptive Feedforward ◽  
The Impact ◽  
Aeroelastic Vibrations

This paper demonstrates the implementation of an adaptive feedforward controller to reduce structural vibrations on a wing typical section. The aeroelastic model includes a structural nonlinearity, which is modelled in a polynomial form. Aeroelastic vibrations are induced by several gusts and atmospheric turbulence, including the discrete “one-minus-cosine” and a notably good approximation in the time-domain to the von Kármán spectrum. The control strategy based on the adaptive feedforward controller has several advantages compared to the standard feedback controller. The controller gains, which are updated in real-time during the gust encounter, are found solving a minimization problem using the finite impulse responses as basis functions. To make progress with the application in aeroelasticity, a single-input single-output controller is designed measuring the wing torsional deformation. For both deterministic and random atmospheric shapes, the controller was found successful in alleviating the aeroelastic vibrations. The impact of the control action on the unmeasured structural modes was found minimal.

Adaptive Feedforward Vibration Control of Flexible Structure With Discrete Sliding Mode Controller

2006 ◽  
Author(s):  
J. Fei
Keyword(s):  
Control System ◽  
Sliding Mode Control ◽  
Sliding Mode ◽  
Feedforward Control ◽  
Flexible Beam ◽  
Sliding Mode Controller ◽  
Control Scheme ◽  
Feedforward Controller ◽  
Adaptive Lms ◽  
Adaptive Feedforward

This paper presents an adaptive feedforward control scheme using the least mean square (LMS) algorithm combined with sliding mode control for a flexible beam using piezoceramic actuator. A finite element model of the dynamic response of flexible beam system with PZT patches is derived and analyzed. Implementation of an adaptive LMS feedforward controller has the advantages of inherent stability and simplicity in design. The proposed adaptive LMS feedforward control system maintains the basic structure of the adaptive feedforward controller, but incorporates reference model in the system. Discrete sliding mode controller is added in the feedback loop to enhance the robustness of control system subjected to the variation of system parameters and external disturbances. Simulation results from flexible beam model verify the effectiveness of the proposed adaptive LMS feedforward with sliding mode control scheme and good disturbance rejection properties.

Zero Phase Error Tracking Algorithm for Digital Control

1987 ◽  
Vol 109 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Masayoshi Tomizuka
Keyword(s):  
Phase Shift ◽  
Motion Control ◽  
Closed Loop ◽  
Feedforward Control ◽  
Phase Error ◽  
Robotic Arms ◽  
Phase Cancellation ◽  
Feedforward Controller ◽  
General Motion ◽  
Zero Phase

A digital feedforward control algorithm for tracking desired time varying signals is presented. The feedforward controller cancels all the closed-loop poles and cancellable closed-loop zeros. For uncancellable zeros, which include zeros outside the unit circle, the feedforward controller cancels the phase shift induced by them. The phase cancellation assures that the frequency response between the desired output and actual output exhibits zero phase shift for all the frequencies. The algorithm is particularly suited to the general motion control problems including robotic arms and positioning tables. A typical motion control problem is used to show the effectiveness of the proposed feedforward controller.

High-Speed End Milling Using a Feedforward Control Architecture

1996 ◽  
Vol 118 (2) ◽  
pp. 178-187 ◽  
Author(s):  
E. D. Tung ◽  
M. Tomizuka ◽  
Y. Urushisaki
Keyword(s):  
High Speed ◽  
Feedforward Control ◽  
End Milling ◽  
Phase Error ◽  
Cutting Speed ◽  
Frequency Domain Analysis ◽  
Maximum Speed ◽  
Drive Control ◽  
Machining Errors ◽  
Feedforward Controller

Experiments are performed for end milling aluminum at 15,000 RPM spindle speed (1,508 m/min cutting speed) and up to 3 m/min table feedrate using an experimental machine tool control system. A digital feedforward controller for feed drive control incorporates the Zero Phase Error Tracking Controller (ZPETC) and feedforward friction compensation. The controller achieves near-perfect (±3 μm) tracking over a 26 mm trajectory with a maximum speed of 2 m/min. The maximum contouring error for a 26 mm diameter circle at this speed is less than 4 μm. Tracking and contouring experiments are conducted for table feedrates as high as 10 m/min. Frequency domain analysis demonstrates that the feedforward controller achieves a bandwidth of 10 Hz without phase distortion. In a direct comparison of accuracy, the machining errors in specimens produced by the experimental controller were up to 20 times smaller than the errors in specimens machined by an industrial CNC.

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