Extended State Observer Based Ascent Trajectory Tracking Method

Author(s):  
Wenming Nie ◽  
Huifeng Li ◽  
Ran Zhang ◽  
Bo Liu

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.

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Weixue Liu ◽  
Jianfang Jiao ◽  
Hamid Reza Karimi ◽  
Jian Jiao

The problem of coordinated control for multiple marine vessels in the presence of external disturbances is considered in this paper. A robust coordinated control algorithm is proposed for multiple marine vessels. The proposed robust coordinated control algorithm is divided into two parts. The first part develops an extended state observer to estimate the disturbances of marine vessels. The second part presents a robust coordinated control algorithm based on the output of the extended state observer. Furthermore, the robust coordinated control algorithm is designed using the dynamic surface control method. In light of the leader-follower strategy, the trajectory for each vessel is defined according to the desired trajectory of the assigned leader and the relative distance with respect to the leader. The effectiveness of the proposed coordination algorithm is demonstrated by the simulation results.


Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 35
Author(s):  
Yu Cao ◽  
Zhongzheng Fu ◽  
Mengshi Zhang ◽  
Jian Huang

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.


2020 ◽  
Vol 42 (14) ◽  
pp. 2733-2743
Author(s):  
Jiqiang Tang ◽  
Tongkun Wei ◽  
Qichao Lv ◽  
Xu Cui

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.


Author(s):  
Dingxin He ◽  
Haoping Wang ◽  
Yang Tian ◽  
Konstantin Zimenko

In this article, an event-triggered discrete extended state observer–based model-free controller is developed for the position and attitude trajectory tracking of a quadrotor with uncertainties and external disturbances. The referred event-triggered discrete extended state observer–based model-free controller is composed of two event-triggered mechanisms, ultra-local model-based discrete extended state observer and proportional-derivative sub-controller. To reduce system output signal transmission, the event-triggered mechanism of output signal which owns dynamic and static threshold is designed. Based on event-triggered output signals, the discrete extended state observer is constructed to obtain the estimations of state values which are utilized as controller’s variables and to compensate for the lumped disturbances. The proportional-derivative sub-controller is adopted to guarantee the convergence of trajectory tracking error. To decrease control input signal transmission, the event-triggered mechanism of input signal that processes static threshold is constructed. Moreover, the stability analysis of overall quadrotor system with the proposed control strategy is investigated using Lyapunov theorem and the Zeno behavior is avoided. Finally, corresponding control scheme for quadrotor system is structured and the numerical comparative simulation and co-simulation experiment are given to demonstrate the effectiveness and performance of the proposed approach.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Peng Gao ◽  
Guangming Zhang ◽  
Huimin Ouyang ◽  
Lei Mei

A novel sliding mode controller (SMC) with nonlinear fractional order PID sliding surface based on a novel extended state observer for the speed operation of a surface-mounted permanent magnet synchronous motor (SPMSM) is proposed in this paper. First, a new smooth and derivable nonlinear function with improved continuity and derivative is designed to replace the traditional nonderivable nonlinear function of the nonlinear state error feedback control law. Then, a nonlinear fractional order PID sliding mode controller is proposed on the basis of the fractional order PID sliding surface with the combination of the novel nonlinear state error feedback control law to improve dynamic performance, static performance, and robustness of the system. Furthermore, a novel extended state observer is designed based on the new nonlinear function to achieve dynamic feedback compensation for external disturbances. Stability of the system is proved based on the Lyapunov stability theorem. The corresponding comparative simulation results demonstrate that the proposed composite control algorithm displays good stability, dynamic properties, and strong robustness against external disturbances.


Author(s):  
Hui Li ◽  
Ruiqin Li ◽  
Jianwei Zhang

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.


2019 ◽  
Vol 52 (9-10) ◽  
pp. 1394-1402 ◽  
Author(s):  
Shengquan Li ◽  
Juan Li ◽  
Hanwen Wu ◽  
Zhongwen Lin

Considering the problems of the internal and external disturbances of wind speed in the direct-drive wind energy conversion system based on a permanent magnet synchronous generator, a novel model predictive control based on the extended state observer method without the accurate mathematical system model is proposed in this paper. First, a model predictive control method is employed as the feedback controller, while the mathematical model of the control system can be adjusted online via the rolling optimization strategy. Second, an extended state observer is introduced to estimate the state variables and lumped disturbances, that is, the internal disturbances including nonlinear characteristic, multi-variety coupling effect, uncertainties of system parameters, and external disturbances including variations of wind speeds and uncertainties of the natural environment. Third, the effect of lumped disturbances can be attenuated by the estimated disturbance value via a feedforward channel. In addition, in order to achieve the real-time speed control performance of the permanent magnet synchronous generator, a speed sensorless algorithm based on a flux observer is proposed to solve the problem of unsuitability of mechanical speed sensor. Finally, the simulation results with several wind speed types show that the proposed sensorless model predictive control with the extended state observer strategy is an effective way to improve the performance of anti-disturbance and ability of tracking maximum wind energy of the wind power control system.


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