Disturbance suppression in active magnetic bearings with adaptive control and extended state observer

2019 ◽  
Vol 234 (2) ◽  
pp. 272-284
Author(s):  
Xudong Guan ◽  
Jin Zhou ◽  
Chaowu Jin ◽  
Yuanping Xu
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
State Observer ◽  
Magnetic Bearing ◽  
Extended State Observer ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Extended State ◽  
Disturbance Suppression ◽  
Bearing System

Some sources of disturbance inevitably exist in magnetic bearings systems in the process of operation. This article proposes a disturbance suppression scheme for active magnetic bearings systems using an improved characteristic model-based all-coefficient adaptive control algorithm. First, the mathematical model of the magnetic bearing system is established. Then, by introducing the extended state observer into the adaptive control, the adaptive control method is improved. And the simulation of the combined control of the adaptive control and extended state observer is carried out based on mathematical model of controlled object. Simulation results demonstrate that this control method can not only adjust the control parameters online, but also estimate and compensate the disturbance in real time, which improves the control performance of the controller. Finally, the feasibility of adaptive control method with extended state observer is verified by experiments. When the sinusoidal disturbance signal is introduced at the 9000 r/min, the vibration displacement of the magnetic bearing system with the improved adaptive controller is reduced around 43%, which is in accordance with the theoretical results.

scholarly journals Extended-State-Observer-Based Super Twisting Control for Pneumatic Muscle Actuators

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 35
Author(s):  
Yu Cao ◽  
Zhongzheng Fu ◽  
Mengshi Zhang ◽  
Jian Huang
Keyword(s):  
Control Method ◽  
Experimental Studies ◽  
State Observer ◽  
Extended State Observer ◽  
Extended State ◽  
Pneumatic Muscle ◽  
System States ◽  
The Stability ◽  
Twisting Control ◽  
Muscle Actuators

This paper presents a tracking control method for pneumatic muscle actuators (PMAs). Considering that the PMA platform only feedbacks position, and the velocity and disturbances cannot be observed directly, we use the extended-state-observer (ESO) for simultaneously estimating the system states and disturbances by using measurable variables. Integrated with the ESO, a super twisting controller (STC) is design based on estimated states to realize the high-precision tracking. According to the Lyapunov theorem, the stability of the closed-loop system is ensured. Simulation and experimental studies are conducted, and the results show the convergence of the ESO and the effectiveness of the proposed method.

Stable control of the high-speeding magnetically suspended rotor based on extended state observer and two-degree freedom internal model control for control moment gyros with serious moving-gimbal effects

2020 ◽  
Vol 42 (14) ◽  
pp. 2733-2743
Author(s):  
Jiqiang Tang ◽  
Tongkun Wei ◽  
Qichao Lv ◽  
Xu Cui
Keyword(s):  
Internal Model ◽  
Feedback Linearization ◽  
Control Method ◽  
Fast Response ◽  
State Observer ◽  
Internal Model Control ◽  
Extended State Observer ◽  
Extended State ◽  
Control Moment ◽  
Model Control

For a magnetically suspended control moment gyro (MSCMG), which is an ideal attitude actuator for its large outputting control moment and fast response, the moving-gimbal effects due to the coupling between the moving gimbal and high-speeding rotor will make the magnetically suspended rotor (MSR) unstable. To improve control precision, both the dynamic model of MSR and the feedback linearization control are done to decouple tilting motion, and poles of the system are reconfigured to reduce control error. To suppress the varying disturbance moments caused by moving-gimbal effects, an extended state observer (ESO) is originally designed to estimate and compensate them timely and accurately. To improve system robustness, a two-degree freedom internal model control (2-DOF IMC) is researched to suppress model error. Compared with existing proportional integral derivative (PID) control method, simulations done on a single gimbal MSCMG with 200 N.m.s angular momentum indicated that this presented control method with ESO and 2-DOF IMC can suppress the moving-gimbal effects more effectively and make the rotor suspension more stable.

scholarly journals Development and Experimental Validation of Auxiliary Rolling Bearing Models for Active Magnetic Bearings (AMBs) Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Anna Tangredi ◽  
Enrico Meli ◽  
Andrea Rindi ◽  
Alessandro Ridolfi ◽  
Pierluca D’Adamio ◽  
...  
Keyword(s):  
Load Capacity ◽  
Critical Phenomenon ◽  
Magnetic Bearing ◽  
Design Tool ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Short Period ◽  
Auxiliary Bearing ◽  
Bearing System

Nowadays, the search for increasing performances in turbomachinery applications has led to a growing utilization of active magnetic bearings (AMBs), which can bring a series of advantages thanks to their features: AMBs allow the machine components to reach higher peripheral speeds; in fact there are no wear and lubrication problems as the contact between bearing surfaces is absent. Furthermore, AMBs characteristic parameters can be controlled via software, optimizing machine dynamics performances. However, active magnetic bearings present some peculiarities, as they have lower load capacity than the most commonly used rolling and hydrodynamic bearings, and they need an energy source; for these reasons, in case of AMBs overload or breakdown, an auxiliary bearing system is required to support the rotor during such landing events. During the turbomachine design process, it is fundamental to appropriately choose the auxiliary bearing type and characteristics, because such components have to resist to the rotor impact; so, a supporting design tool based on accurate and efficient models of auxiliary bearings is very useful for the design integration of the Active Magnetic Bearing System into the machine. This paper presents an innovative model to accurately describe the mechanical behavior of a complete rotor-dynamic system composed of a rotor equipped with two auxiliary rolling bearings. The model, developed and experimentally validated in collaboration with Baker Hughes a GE company (providing the test case and the experimental data), is able to reproduce the key physical phenomena experimentally observed; in particular, the most critical phenomenon noted during repeated experimental combined landing tests is the rotor forward whirl, which occurs in case of high friction conditions and greatly influences the whole system behavior. In order to carefully study some special phenomena like rotor coast down on landing bearings (which requires long period of time to evolve and involves many bodies and degrees of freedom) or other particular events like impacts (which occur in a short period of time), a compromise between accuracy of the results and numerical efficiency has been pursued. Some of the elements of the proposed model have been previously introduced in literature; however the present work proposes some new features of interest. For example, the lateral and the axial models have been properly coupled in order to correctly reproduce the effects observed during the experimental tests and a very important system element, the landing bearing compliant suspension, has been properly modelled to more accurately describe its elastic and damping effects on the system. Furthermore, the model is also useful to characterize the frequencies related to the rotor forward whirl motion.

Extended State Observer Based Ascent Trajectory Tracking Method

2017 ◽  
Author(s):  
Wenming Nie ◽  
Huifeng Li ◽  
Ran Zhang ◽  
Bo Liu
Keyword(s):  
Trajectory Tracking ◽  
Control Method ◽  
State Observer ◽  
Linearization Method ◽  
Extended State Observer ◽  
Extended State ◽  
External Disturbances ◽  
Modeling Uncertainties ◽  
Trajectory Tracking Controller ◽  
Linearization Errors

The ascent trajectory tracking problem of a launch vehicle is investigated in this paper. To improve the conventional trajectory linearization method which usually omits the linearization errors, the extended state observer (ESO) is employed in this paper to timely estimate the total disturbance which consists of the external disturbances and the modeling uncertainties resulting from linearization error. It is proven that the proposed trajectory tracking controller can guarantee the desired performance despite both external disturbances and the modeling uncertainties. Moreover, compared with the conventional linearization control method, the proposed controller is shown to have much better performance of uncertainty rejection. Finally, the feasibility and performance of this controller are illuminated via simulation studies.

On the design of extended state observer-based robust finite controller: For underactuated robotic system with multiple sources of uncertainties

2020 ◽  
pp. 014233122096611
Author(s):  
Hui Li ◽  
Ruiqin Li ◽  
Jianwei Zhang
Keyword(s):  
Control Method ◽  
External Disturbance ◽  
Control Process ◽  
Output Feedback Control ◽  
State Observer ◽  
Robotic System ◽  
Extended State Observer ◽  
Extended State ◽  
Multiple Sources ◽  
Parameter Uncertainties

Controlling an underactuated robot is always an important research and engineering issue, especially when the robot is suffering from multiple sources of uncertainties, such as unmodeled dynamics, external disturbance, and parameter uncertainties. To cope with these uncertainties in such uncertain nonlinear systems which is not fully-actuated, this paper proposes a control method that can actively estimate these uncertainties via the extended state observer (ESO), under the scheme of output-feedback control, the lumped uncertainties can be online estimated and actively compensated. Every joint of the underactuated robotic system can robustly reach the pre-given state in finite-time even though there are only fewer joints than the actual number of joints that can be controlled directly. The experimental results demonstrate the control process and validate that the proposed method is feasible for the studied underactuated robotic system.

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