scholarly journals Adaptive Digital Disturbance Rejection Controller Design for Underwater Thermal Vehicles

2021 ◽  
Vol 9 (4) ◽  
pp. 406
Author(s):  
Guohui Wang ◽  
Yanan Yang ◽  
Shuxin Wang

Underwater thermal vehicles, as ocean observation tools, are frequently affected by environment disturbances such as waves and currents, which may cause degradation of the observation accuracy of the vehicles. Consequently, it is important to design a controller for a vehicle that can resist ocean disturbance. In this study, an underwater thermal vehicle principle is introduced, and the mathematical model is established in the vertical plane motion. On this basis, an adaptive digital disturbance suppression control method is proposed. For known disturbance parameters, this controller could compensate for external disturbances by pre-setting control parameters using the internal model principle and parameterizations method. For the case where the disturbance parameters are unknown, disturbance parameter estimation method based on forgetting factor least-squares method is proposed to transform the unknown parameter disturbance into a disturbance with known parameters, which is then suppressed by the adaptive digital disturbance rejection control approach. This solution could effectively solve the challenges caused by parameter uncertainty and unknown time-varying ocean external disturbances. Finally, simulations are carried out for the Petrel underwater thermal glider as an example. The simulation results show the proposed control method’s superiority and inherent robustness.

2016 ◽  
Vol 19 (4) ◽  
pp. 45-64
Author(s):  
Phuong Minh Le ◽  
Duy Vo Duc Hoang ◽  
Hoa Thi Xuan Pham ◽  
Huy Minh Nguyen

This paper presents a new load sharing control between paralleled three-phase inverters in an islanded-microgrid based on the line impedance estimation online by the use of the Kalman filter. We can solve the mismatch of power sharing when the line impedance changes due to the temperature and frequency, significant differences of line parameters and requirements of Plug-and-Play mode of inverters connected to the microgrid. Moreover, the paper also presents a new Droop control method working with the line impedance which is different from the Droop traditional algorithm when the line impedance is assumed pure resistance R or pure inductance X. In the paper, the line impedance estimation for parallel inverters uses the least squares method combined with Kalman filter. In addition, secondary control loops are designed to restore the voltage amplitude and frequency of the microgrid by using a combined nominal value SOGI-PLL with generalized integral block and phase lock loop to exactly monitor the voltage magnitude and frequency phase at common PCC. Control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of the power sharing. The simulation results have shown the accuracy of the proposed control method. Therefore, the proposed adaptive droop control method based on line impedance estimation can be an alternative one for load sharing control in islanded microgrids.


Author(s):  
Zhengrong Chu ◽  
Christine Wu ◽  
Nariman Sepehri

In this article, a new automated steering control method is presented for vehicle lane keeping. This method is a combination between the linear active disturbance rejection control and the quantitative feedback theory. The structure of the steering controller is first determined based on the linear active disturbance rejection control, then the controller is tuned in the framework of the quantitative feedback theory to meet the prescribed design specifications on sensitivity and closed-loop stability. The parameter uncertainties of the vehicle system are considered at the tuning stage. The proposed steering controller is simulated and tested on a scale vehicle. Both the simulation and experimental results demonstrate that the scale vehicle controlled by the proposed controller is able to perform the lane keeping. In the experiments, the lateral offset between the scale vehicle and the road centerline is regulated within the acceptable ranges of ±0.03 m during straight lane keeping and ±0.15 m during curved lane keeping. The proposed controller is easy to be implemented and is simple without requiring complex calculations and measurements of vehicle states. Simulations also show that the control method can be implemented on a full-scale vehicle.


Author(s):  
Zhi Qi ◽  
Qianyue Luo ◽  
Hui Zhang

In this paper, we aim to design the trajectory tracking controller for variable curvature duty-cycled rotation flexible needles with a tube-based model predictive control approach. A non-linear model is adopted according to the kinematic characteristics of the flexible needle and a bicycle method. The modeling error is assumed to be an unknown but bounded disturbance. The non-linear model is transformed to a discrete time form for the benefit of predictive controller design. From the application perspective, the flexible needle system states and control inputs are bounded within a robust invariant set when subject to disturbance. Then, the tube-based model predictive control is designed for the system with bounded state vector and inputs. Finally, the simulation experiments are carried out with tube-based model predictive control and proportional integral derivative controller based on the particle swarm optimisation method. The simulation results show that the tube-based model predictive control method is more robust and it leads to much smaller tracking errors in different scenarios.


Author(s):  
Kaveh Merat ◽  
Jafar Abbaszadeh Chekan ◽  
Hassan Salarieh ◽  
Aria Alasty

In this article by introducing and subsequently applying the Min–Max method, chaos has been suppressed in discrete time systems. By using this nonlinear technique, the chaotic behavior of Behrens–Feichtinger model is stabilized on its first and second-order unstable fixed points (UFP) in presence and absence of noise signal. In this step, a comparison has also been carried out among the proposed Min–Max controller and the Pyragas delayed feedback control method. Next, to reduce the computation required for controller design, the clustering method has been introduced as a quantization method in the Min–Max control approach. To improve the performance of the acquired controller through clustering method obtained with the Min–Max method, a linear optimal controller is also introduced and combined with the previously discussed nonlinear control law. The resultant combined controller has been applied on the Henon map and through comparison with both Pyragas controller, and the linear optimal controller alone, its advantages are discussed.


Author(s):  
Mohammed Ali ◽  
Charles K. Alexander

The tracking performance of a robot manipulator is controlled using nonlinear active disturbance rejection control (ADRC). The proposed method does not require the complete knowledge of the plant’s parameters, and external disturbances since it is based on the rejection and estimation of the unknown internal dynamics and external disturbances. The proposed method is simple and has minimal tuning parameters. The robustness of the proposed method is discussed against parameter uncertainties and disturbances. First, the mathematical model of the manipulator is developed. ADRC theory is explained. The manipulator is represented in ADRC form. ADRC’s tracking performance for the joints and end-effector is compared to the tracking performance of the robust passivity (RP) control. The simulations prove that the proposed control method achieves good tracking performance compared to RP control. It is shown that ADRC has a lower energy consumption compared to RP control by calculating the power in the input signals.


Author(s):  
Trupti Ranka ◽  
Mario Garcia-Sanz ◽  
John M. Ford

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.


Permanent-magnet (PM) motors are employed in numerous industrial control applications for their high efficiency, simple mechanism and low cost. In most of the applications, either the plant model is inaccurately defined or the plant parameters are prone to variations over period of time. Also, in most of the applications, have a requirement of good tracking as well as good disturbance rejection, two competing requirements. The controller should cater to the parameter variations as well as provide robust performance against external disturbances and hence requires a robust control approach towards designing a controller. A classical PID controller, which lacks robustness requirements is augmented by H∞ optimization based gain tuning to meet the robustness requirements. This paper discusses a PID controller design using H∞ optimization approach. Different performance goals for tracking and disturbance rejection are defined and PID gains are tuned to meet the goals in H∞ sense. A commercial Maxon RE35 motor is selected for modeling and simulation


2012 ◽  
Vol 479-481 ◽  
pp. 71-75 ◽  
Author(s):  
Gang Zheng ◽  
Jian Dong Wu ◽  
Ming Wei Kuang ◽  
Deng Zhang ◽  
Yang Yang

For any electric vehicle on the road, it is inevitable to be influenced by parameter uncertainties and some kinds of disturbance torques, which present challenge for the controller design in the electric vehicle. Therefore, control of the electric vehicle to achieve the safety running requirement becomes important. In this paper, we investigate the control method for electric drive system of the electric vehicle from both theoretical and applied perspectives, then, speed loop inverse based disturbance rejection control strategy is proposed. The proposed approach is illustrated by implementing it into an experimental platform. The experimental results demonstrated that the proposed control method can achieve rapid response to current variation at operating frequency of electric vehicle, and substantially suppress the adverse effect of current variation at high frequency.


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4675 ◽  
Author(s):  
Xiaohuan Lai ◽  
Haipeng Pan ◽  
Xinlong Zhao

An adaptive control scheme is proposed for a class of uncertain pure-feedback nonlinear systems preceded by asymmetric hysteresis nonlinearity. The asymmetric property is described by the modified Bouc-Wen model based on the proposed asymmetric factor. State variables in the controller design are directly replaced with nonaffine functions to address the control problem caused by nonaffine appearance. Moreover, the control method can handle systems with external disturbances and guarantee the global stability of all the signals in the closed-loop system. The feasibility of the control scheme is verified by a simulation example and experimental results.


Author(s):  
Lei Chu ◽  
Yuqun Han ◽  
Shanliang Zhu ◽  
Mingxin Wang

This paper presents an adaptive multi-dimensional Taylor network (MTN) control approach for a class of nonlinear systems with unknown parameters. MTN is employed to identify unknown nonlinear characteristics existing in the system, and then a novel adaptive MTN tracking control method is proposed, via backstepping technique. In the controller design, double adaptive laws are designed and appropriate Lyapunov functions are chosen to overcome the difficulties caused by the unknown parameters. The designed controller can guarantee that all the variables in the closed-loop systems are bounded and the tracking error can be arbitrarily small. Finally, simulation results are presented to verify the effectiveness of the proposed approach.


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