BACKSTEPPING CONTROLLER WITH PSO FOR AN UNDERACTUATED X4-AUV

2016 ◽  
Vol 78 (6-13) ◽  
Author(s):  
Nur Fadzillah Harun ◽  
Zainah Md. Zain
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Control Method ◽  
Fitness Function ◽  
Control Technique ◽  
Underactuated System ◽  
Effective Response ◽  
Control Approach ◽  
Comparison Results ◽  
Highly Nonlinear ◽  
Backstepping Controller

X4-AUV is a type of an autonomous underwater vehicle (AUV) which has 4 inputs with six degrees of freedoms (6-DOFs) in motion and is classified under an underactuated system. Controlling an underactuated AUV is difficult tasks because of the highly nonlinear dynamic, uncertainties in hydrodynamics behaviour and mostly those systems fails to satisfy Brockett’s Theorem. It usually required a nonlinear control approach and this paper proposed a backstepping control method with Particle Swarm Optimization (PSO) to stabilize an underactuated X4-AUV system. In backstepping controller design, accurate parameters are important in order to obtain the maximal and effective response. Hence, PSO is implemented to obtain optimal parameters for backstepping controller and its carry out by minimizing the fitness function. Comparison results illustrated the controller with PSO has a smooth and fast transient response into the desired point compared than manually tune controller parameters and also improve the system performances. The validity of the proposed control technique for an underactuated X4-AUV demonstrates through simulation.

COMPARISON OF AN X4-AUV PERFORMANCE USING A BACKSTEPPING AND INTEGRAL BACKSTEPPING APPROACH

2016 ◽  
Vol 78 (6-11) ◽  
Author(s):  
Nur Fadzillah Harun ◽  
Zainah Md. Zain
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Control Method ◽  
Underwater Vehicle ◽  
Control Technique ◽  
Underactuated System ◽  
Control Law ◽  
Backstepping Approach ◽  
Highly Nonlinear ◽  
Backstepping Controller ◽  
Propose Control System

X4-AUV is a type of an autonomous underwater vehicle (AUV) which has 4 inputs with six degrees of freedoms (6-DOFs) in motion and is classified under an underactuated system. Controlling an underactuated system is difficult tasks because of the highly nonlinear dynamic, uncertainties in hydrodynamics behaviour and mostly those systems fails to satisfy Brockett’s Theorem. It usually required nonlinear control technique and this paper proposed an integral backstepping controller for stabilizing an underactuated X4-AUV. A control law is designed for the system in new state space using integral backstepping. The performance of the proposed control method is examined through simulation and results demonstrate all motion is stabilized and convergence into desired point. We also compared the results with backstepping approach to see the effectiveness of the propose control system.

scholarly journals Comparison of a Triple Inverted Pendulum Stabilization Using Optimal Control Technique

2020 ◽  
Author(s):  
Mustefa Jibril ◽  
Messay Tadese ◽  
Eliyas Alemayehu Tadese
Keyword(s):  
Optimal Control ◽  
Impulse Response ◽  
Inverted Pendulum ◽  
Control Method ◽  
Pole Placement ◽  
Control Technique ◽  
Comparison Results ◽  
Highly Nonlinear ◽  
Pole Placement Controller ◽  
Triple Inverted Pendulum

In this paper, modelling design and analysis of a triple inverted pendulum have been done using Matlab/Script toolbox. Since a triple inverted pendulum is highly nonlinear, strongly unstable without using feedback control system. In this paper an optimal control method means a linear quadratic regulator and pole placement controllers are used to stabilize the triple inverted pendulum upside. The impulse response simulation of the open loop system shows us that the pendulum is unstable. The comparison of the closed loop impulse response simulation of the pendulum with LQR and pole placement controllers results that both controllers have stabilized the system but the pendulum with LQR controllers have a high overshoot with long settling time than the pendulum with pole placement controller. Finally the comparison results prove that the pendulum with pole placement controller improve the stability of the system.

Position and Attitude Control of Deep-Space Spacecraft Formation Flying Via Virtual Structure and θ-D Technique

2007 ◽  
Vol 129 (5) ◽  
pp. 689-698 ◽  
Author(s):  
Ming Xin ◽  
S. N. Balakrishnan ◽  
H. J. Pernicka
Keyword(s):  
Attitude Control ◽  
Formation Flying ◽  
Libration Point ◽  
Suboptimal Control ◽  
Control Technique ◽  
Deep Space ◽  
Control Approach ◽  
Spacecraft Formation ◽  
Spacecraft Formation Flying ◽  
Highly Nonlinear

Control of deep-space spacecraft formation flying is investigated in this paper using the virtual structure approach and the θ-D suboptimal control technique. The circular restricted three-body problem with the Sun and the Earth as the two primaries is utilized as a framework for study and a two-satellite formation flying scheme is considered. The virtual structure is stationkept in a nominal orbit around the L2 libration point. A maneuver mode of formation flying is then considered. Each spacecraft is required to maneuver to a new position and the formation line of sight is required to rotate to a desired orientation to acquire new science targets. During the rotation, the formation needs to be maintained and each spacecraft’s attitude must align with the rotating formation orientation. The basic strategy is based on a “virtual structure” topology. A nonlinear model is developed that describes the relative formation dynamics. This highly nonlinear position and attitude control problem is solved by employing a recently developed nonlinear control approach, called the θ-D technique. This method is based on an approximate solution to the Hamilton-Jacobi-Bellman equation and yields a closed-form suboptimal feedback solution. The controller is designed such that the relative position error of the formation is maintained within 1cm accuracy.

Autonomous line follower robot with fuzzy based hybrid controller

2020 ◽  
Vol 39 (5) ◽  
pp. 6021-6031
Author(s):  
Anıl Sezgin ◽  
Ömer Çetin
Keyword(s):  
Autonomous Navigation ◽  
Control Method ◽  
Hybrid Control ◽  
Ground Surface ◽  
Control Technique ◽  
Mobile Platforms ◽  
Control Approach ◽  
Advantages And Disadvantages ◽  
External Supports ◽  
Smart Cars

The autonomous navigation problem is currently a popular research topic encountered in many different areas, from smart cars to automated warehouse operations. Autonomous navigation of robotic systems is examined in two basic areas, with and without external supports. Even if the robot uses external supports (like GPS, road signs, ground surface lines, barcodes etc.) or positioning itself with internal sensors (like gyro, IMU, etc.), it independently needs a control method to follow the desired route. When the widely used control approaches in the literature are examined, PID and fuzzy-based approaches are frequently encountered. They both offer advantages and disadvantages. Within the scope of this study, the positive aspects of both of control approaches are utilized and the hybrid control approach for a robot that can autonomously follow the ground line presented as an external reference is mentioned. The success of the approach was tested comparatively on an exemplary mobile platform. The applied results obtained experimentally showed that a more efficient fuzzy logic-based hybrid control method could be developed. In addition, the effect of the number of conditions in the rule table on the success of the hybrid control technique is shown in the study. It has also been experimentally demonstrated that the success of hybrid control approach with a limited low power consuming ARM based processor that is suitable to control most of lightweight mobile platforms.

Robust Joint and Cartesian Control of Underactuated Manipulators

1996 ◽  
Vol 118 (3) ◽  
pp. 557-565 ◽  
Author(s):  
Marcel Bergerman ◽  
Yangsheng Xu
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Variable Structure ◽  
Joint Space ◽  
Control Technique ◽  
Underactuated System ◽  
Underactuated Manipulator ◽  
Underactuated Manipulators ◽  
Compact Design ◽  
Weight Decrease

Underactuated manipulators are robot manipulators composed of both active and passive joints in serial chain mechanisms. The study of underactuation is significant for the control of a variety of rigid-body systems, such as free-floating robots in space and gymnasts, whose structure include passive joints. For mechanisms with large degrees of freedom, such as hyper-redundant snake-like robots and multi-legged machines, the underactuated structure allows a more compact design, weight decrease, and energy saving. Furthermore, when one or more joints of a standard manipulator fail, it becomes an underactuated mechanism; a control technique for such system will increase the reliability and fault-tolerance of current and future robots. The goal of this study is to present a robust control method for the control of underactuated manipulators subject to modeling errors and disturbances. Because an accurate modelling of the underactuated system is more critical for control issues than it is for standard manipulators, this method is significant in practice. Variable structure controllers are proposed in both joint space and Cartesian space, and a comprehensive simulation study is presented to address issues such as computation, robustness, and feasibility of the methods. Experimental results demonstrate the actual applicability of the proposed methods in a real two-degrees-of-freedom underactuated manipulator. As it will be shown, the proposed variable structure controller provides robustness againstboth disturbances and parametric uncertainties, a characteristic not present on previously proposed PID-based schemes.

scholarly journals NonlinearH∞Optimal Control Scheme for an Underwater Vehicle with Regional Function Formulation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zool H. Ismail ◽  
Matthew W. Dunnigan
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Tracking Error ◽  
Underwater Vehicle ◽  
Control Technique ◽  
Control Law ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Control Scheme ◽  
Highly Nonlinear ◽  
Region Tracking

A conventional region control technique cannot meet the demands for an accurate tracking performance in view of its inability to accommodate highly nonlinear system dynamics, imprecise hydrodynamic coefficients, and external disturbances. In this paper, a robust technique is presented for an Autonomous Underwater Vehicle (AUV) with region tracking function. Within this control scheme, nonlinearH∞and region based control schemes are used. A Lyapunov-like function is presented for stability analysis of the proposed control law. Numerical simulations are presented to demonstrate the performance of the proposed tracking control of the AUV. It is shown that the proposed control law is robust against parameter uncertainties, external disturbances, and nonlinearities and it leads to uniform ultimate boundedness of the region tracking error.

scholarly journals Does city lockdown prevent the spread of COVID-19? New evidence from the synthetic control method

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiaoxuan Yang
Keyword(s):  
Control Method ◽  
Human Mobility ◽  
Initial Period ◽  
Sample Selection ◽  
Weighted Average ◽  
Synthetic Control ◽  
Population Mobility ◽  
Effective Response ◽  
Control Approach ◽  
Suppression Effect

Abstract Background At 10 a.m. on January 23, 2020 Wuhan, China imposed a 76-day travel lockdown on its 11 million residents in order to stop the spread of COVID-19. This lockdown represented the largest quarantine in the history of public health and provides us with an opportunity to critically examine the relationship between a city lockdown on human mobility and controlling the spread of a viral epidemic, in this case COVID-19. This study aims to assess the causal impact of the Wuhan lockdown on population movement and the increase of newly confirmed COVID-19 cases. Methods Based on the daily panel data from 279 Chinese cities, our research is the first to apply the synthetic control approach to empirically analyze the causal relationship between the Wuhan lockdown of its population mobility and the progression of newly confirmed COVID-19 cases. By using a weighted average of available control cities to reproduce the counterfactual outcome trajectory that the treated city would have experienced in the absence of the lockdown, the synthetic control approach overcomes the sample selection bias and policy endogeneity problems that can arise from previous empirical methods in selecting control units. Results In our example, the lockdown of Wuhan reduced mobility inflow by approximately 60 % and outflow by about 50 %. A significant reduction of new cases was observed within four days of the lockdown. The increase in new cases declined by around 50% during this period. However, the suppression effect became less discernible after this initial period of time. A 2.25-fold surge was found for the increase in new cases on the fifth day following the lockdown, after which it died down rapidly. Conclusions Our study provided urgently needed and reliable causal evidence that city lockdown can be an effective short-term tool in containing and delaying the spread of a viral epidemic. Further, the city lockdown strategy can buy time during which countries can mobilize an effective response in order to better prepare. Therefore, in spite of initial widespread skepticism, lockdowns are likely to be added to the response toolkit used for any future pandemic outbreak.

Backstepping Control Method for the Trajectory Tracking for the Underactuated Autonomous Underwater Vehicle

2013 ◽  
Vol 798-799 ◽  
pp. 484-488 ◽  
Author(s):  
Lei Wan ◽  
Nan Sun ◽  
Yu Lei Liao
Keyword(s):  
Control System ◽  
Trajectory Tracking ◽  
Autonomous Underwater Vehicle ◽  
Control Method ◽  
Autonomous Underwater Vehicles ◽  
Path Following ◽  
Underactuated System ◽  
Strong Nonlinearity ◽  
Parameter Uncertainties ◽  
Path Following Control

The underactuated autonomous underwater vehicles (AUV) have the characteristics of strong nonlinearity and model uncertainty. A method of backstepping path following control was raised for the trajectory tracking control problem of the AUV under Serret-Frenet frame. It transformed the original underactuated system into an actuated nonlinear system based on simplified analysis. A backstepping trajectory tracking controller was proposed based on backstepping method. By means of Lyapunov stability theory, it was proven that the proposed controller can guarantee the path following control system globally asymptotically stable. Simulation experiments show that the control system has good adaptability and robustness in case of parameter uncertainties and external disturbances to avoid shaking of performance.

scholarly journals Neural Network Control for Trajectory Tracking and Balancing of a Ball-Balancing Robot with Uncertainty

2021 ◽  
Vol 11 (11) ◽  
pp. 4739
Author(s):  
Hyo-Geon Jang ◽  
Chang-Ho Hyun ◽  
Bong-Seok Park
Keyword(s):  
Neural Network ◽  
Control System ◽  
Trajectory Tracking ◽  
Control Method ◽  
Tracking Error ◽  
System Structure ◽  
Underactuated System ◽  
Dynamic Surface ◽  
Comparison Results ◽  
Balancing Robot

In this paper, a neural-network-based control method to achieve trajectory tracking and balancing of a ball-balancing robot with uncertainty is presented. Because the ball-balancing robot is an underactuated system and has nonlinear couplings in the dynamic model, it is challenging to design a controller for trajectory tracking and balancing. Thus, various approaches have been proposed to solve these problems. However, there are still problems such as the complex control system and instability. Therefore, the objective of this paper was to propose a solution to these problems. To this end, we developed a virtual angle-based control scheme. Because the virtual angle was used as the reference angle to achieve trajectory tracking while keeping the balance of the ball-balancing robot, we could solve the underactuation problem using a single-loop controller. The radial basis function networks (RBFNs) were employed to compensate uncertainties, and the controller was designed using the dynamic surface control (DSC) method. From the Lyapunov stability theory, it was proven that all errors of the closed-loop control system were uniformly ultimately bounded. Therefore, the control system structure was simple and ensured stability in achieving simultaneous trajectory tracking and balancing of the ball-balancing robot with uncertainty. Finally, the simulation results are given to verify the performance of the proposed controller through comparison results. As a result, the proposed method showed a 19.2% improved tracking error rate compared to the existing method.

A Frequency-Based Control Methodology for the Reduction of Payload Oscillations in Hydraulic Load Handling Machines

2015 ◽  
Author(s):  
Riccardo Bianchi ◽  
Guido Francesco Ritelli ◽  
Andrea Vacca ◽  
Massimiliano Ruggeri
Keyword(s):  
Control Method ◽  
Control Technique ◽  
Control Approach ◽  
Online Identification ◽  
Hydraulic Load ◽  
Pressure Feedback ◽  
Hydraulic Crane ◽  
Mobile Machinery ◽  
Load Handling ◽  
Control Methodology

This paper presents a non-model based control approach to reduce payload oscillations in hydraulic load handling machines. Hydraulic mobile machinery are subjected to different kinds of vibrations related to their actuation, which hamper productivity and safety. In particular, these oscillations can occur at the machine structure, at the operator cabin or at the payload. While several techniques have been proposed to specifically address the first two forms of vibrations, the problem of limiting payload oscillations has encountered less attention by researchers in the fluid power field. The particular control technique proposed in this work is pressure feedback, and utilizes pressure sensor which can be located in well protected areas of the hydraulic system of the machine. The control method is based on an online identification of the frequency of load oscillations and selectively reduces these oscillations by acting on the hydraulic actuators of the machine. With reference to a hydraulic crane installed at the authors’ research center, this paper details the methodology, particularly focusing on the technique utilized for the online identification of the nature of load oscillations. Experimental results are presented to show the effectiveness of the proposed method to reduce payload oscillations, and demonstrate its applicability for hydraulic load handling machines.

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