Time-varying high-gain observers for numerical differentiation

2002 ◽  
Vol 47 (9) ◽  
pp. 1565-1569 ◽  
Author(s):  
Y. Chitour
Keyword(s):  
Numerical Differentiation ◽  
High Gain ◽  
Time Varying

Observer-based feedback for the magnetic levitation system

2011 ◽  
Vol 34 (4) ◽  
pp. 422-435 ◽  
Author(s):  
Jerzy Baranowski ◽  
Paweł Piątek
Keyword(s):  
Magnetic Levitation ◽  
Numerical Differentiation ◽  
Careful Analysis ◽  
High Gain ◽  
Model Parameters ◽  
Stable Operation ◽  
Levitation System ◽  
Non Linear ◽  
Magnetic Levitation System ◽  
The Mathematical Model

Control of active magnetic bearings is an important area of research. The laboratory magnetic levitation system can be interpreted as a model of a single axis of bearings and is a useful testbed for control algorithms. The mathematical model of this system is highly non-linear and requires careful analysis and identification. The system is observable from position measurements as long as the electromagnet is powered as shown during the research. Practically measurable signals are the position and the coil current. The velocity that is necessary for any stabilizing control usually is obtained by numerical differentiation of the position. A more sophisticated approach is to estimate the velocity with an observer. Efficient observer types for this system are high-gain and non-linear reduced observers. The velocity estimated by an observer can be effectively used instead of a derivative in PID control of the position. Such an approach substantially improves control quality and extends the range of system’s stable operation. Even greater improvement is introduced by the addition of the non-linear feedforward to the control structure. The best results, provided the model parameters are correctly identified, are obtained with a control system consisting of the PID controller, the high-gain observer and the non-linear feedforward.

scholarly journals High gain observer design for nonlinear systems with time varying delayed measurements

2011 ◽  
Vol 44 (1) ◽  
pp. 692-696 ◽  
Author(s):  
V. Van Assche ◽  
T. Ahmed-Ali ◽  
C.A.B. Hann ◽  
F. Lamnabhi-Lagarrigue
Keyword(s):  
Nonlinear Systems ◽  
High Gain ◽  
Observer Design ◽  
Time Varying ◽  
High Gain Observer ◽  
Delayed Measurements

Manipulator Joints Servo Motor Control Strategy

2013 ◽  
Vol 694-697 ◽  
pp. 1629-1633
Author(s):  
Lin Yang ◽  
Yong Yi He ◽  
Shuai Guo ◽  
Sheng Bao
Keyword(s):  
Control Method ◽  
Lagrange Equation ◽  
High Gain ◽  
Servo Control ◽  
Time Varying ◽  
Servo Motor ◽  
Current Feedback ◽  
Speed Regulation ◽  
High Dynamic ◽  
Manipulator Control

The manipulator with the characteristics of strong coupling, non-linear and time-varying. According to those, the article researched the manipulator properties through dynamics and SPMSM speed regulation mechanical property, calculating the torques through Lagrange equation and transferring to relative current equations, then bringing out the manipulator servo control method based on SVPWM and high gain current feedback. Thus, the joints controls are simplified to independent joints servo motors control, realizing the high dynamic manipulator control. Finally, the validation of this method is verified by setting up the experimental platform with SPMSM and ZX165U manipulator.

scholarly journals Robust Synchronization of Class Chaotic Systems Using Novel Time-Varying Gain Disturbance Observer-Based Sliding Mode Control

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yang Wang ◽  
Zhen Wang ◽  
Lingyun Kong
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Chaotic Systems ◽  
Sliding Mode ◽  
High Gain ◽  
Time Varying ◽  
Mode Control ◽  
Control Precision ◽  
Robust Synchronization ◽  
And Control

For synchronization of a class of chaotic systems in the presence of nonvanishing uncertainties, a novel time-varying gain observer-based sliding mode control is proposed. First, a novel time-varying gain disturbance observer (TVGDO) is developed to estimate the uncertainties. Then, by using the output of TVGDO to modify sliding mode control (SMC), a new TVGDO-based SMC scheme is developed. Although the observation and control precision of conventional fixed gain disturbance observer-based control (FGDOC) for chaotic systems can be guaranteed by a high observer gain, the undesirable spike problem may be caused by the high gain if the initial values of estimate and true states are not equal. The most attractive feature of this work is that the newly proposed TVGDO can eliminate the spike problem by developing a time-varying gain scheme. Finally, the effectiveness of the proposed method is demonstrated by the numerical simulation.

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