Sliding Mode Variable Structure Control Research Articles

The adaptive sliding mode control using improved genetic algorithm tuning PID controller for the planetary rover

PurposeThe purpose of this paper is to resolve the problem of the dynamic response performance of the driving control system for a six-wheeled planetary rover. An adaptive sliding mode controller based on an improved genetic algorithm (IGA) to tune PID sliding surface parameters was used in the driving control system of the planetary rover.Design/methodology/approachFirst, the mathematical model of planetary rover driving control is established. Second, according to sliding mode variable structure control, an equivalent controller and a disturbance controller are constructed to solve the problem of a multi-disturbance nonlinear driving control system of planetary rovers and an IGA is used to tune PID parameters.FindingsSimulation results show that the proposed control algorithm improves the accuracy of the driving control system and optimizes the smoothness of rover motion control.Practical implicationsThe controller based on the IGA to tune PID sliding surface parameters has good self-adaptability and real-time controllability for the control object which is difficult to present a precise mathematical model.Originality/valueThe advanced control method is adopted to solve the uncertainty and external interference of planetary rovers in a complex environment. The mathematical model of the six-wheeled rover is established as the control object and the uncertainty and external disturbance of the model are considered. The controller based on IGA has good adaptability and real-time performance and the control algorithm can be used to drive robots in complex environments.

Global-Equivalent Sliding Mode Control Method for Bridge Crane

A wide application of sliding mode variable structure control as a nonlinear robust control method, has been witnessed in anti-swing positioning control of bridge crane system. Aiming at the problem that the sliding mode variable structure control system of bridge crane is not robust in approaching process, a new Global-Equivalent Sliding Mode Controller (GESMC) based on bridge crane system is proposed. This controller can realize the anti-sway positioning control of the bridge crane system under the condition of uncertain model parameters and external disturbance. The proposed controller, different from the traditional sliding mode control, excels in improving system robustness through keeping the system states in the sliding surface during the whole response process. Specifically, it initiates with the design of a global sliding surface, which can eliminate the sliding mode approach process of the system and achieve global robustness in the system. Afterwards, a new switching function combined with the equivalent sliding mode control method is incorporated to effectively reduce the chattering generated when the system reaches the sliding mode manifold. Its asymptotic stability is proven without a priori knowledge on the bounds of unknown disturbances by using the Lyapunov stability theory. Lastly, the simulation conducted verifies the effectiveness and robustness of the GESMC proposed in this paper and meanwhile demonstrates a comparatively favorable performance for the GESMC in reducing chattering.

A Novel Cooperative Control System of Multi-Missile Formation Under Uncontrollable Speed

This article investigates a novel cooperative control system based on the sliding mode variable structure control theory for multi-missile formation flight. It is desired in practice to form and maintain the formation under the premise of uncontrollable missile speed. First, under the inertial coordinate system, we obtain the model of the formation control problem using the relative position of the leader to the follower. Then, we perform acceleration conversion and combine it to this model, getting the form of the formation problem model in the ballistic coordinate system. The finished model is useful for researchers to design the formation controller on this basis. Besides, the sliding mode variable structure control theory is used to design the formation controller for the system not considering disturbances and considering disturbances. Then we use the Lyapunov stability theory to analyze the stability of the formation control system. Finally, we compare our method with another method which requires controllable speed. According to numerical simulations, the method proposed in this article can achieve similar relative position errors under the condition of uncontrollable speed. And the robustness, versatility and formation adaptability of the method we propose are confirmed by simulation results.

Dynamic Modeling and Error Analysis of a Cable-Linkage Serial-Parallel Palletizing Robot

The efficiency and accuracy for parallel robot play a significant role in the industrial production process. In order to further improve the motion performance of parallel robot, this paper focuses on the study of mechanism design, dynamic modeling and error analysis of a cable-linkage serial-parallel palletizing robot (CSPR). Firstly, the CSPR is designed as a series-parallel hybrid mechanism driven by flexible cables, which can effectively reduce the inertia and improve the dynamic response. As is known that kinematic design optimization of compliant mechanisms requires accurate yet efficient mathematical models, the kinematics and dynamic models are established by the homogeneous coordinate transformation method and Lagrange equation. Based on the dynamic mathematical model of the robot, a variety of sensors are chosen to construct the hardware control system and the sliding mode variable structure control strategy is also designed based on motion errors. Then, the motion performance and load carrying capacity of the CSPR were analyzed and compared in different operating conditions respectively, and the results verify the validity and efficiency of the mechanism.

Automatic Parking Path Planning and Tracking Control Research for Intelligent Vehicles

As a key technology for intelligent vehicles, automatic parking is becoming increasingly popular in the area of research. Automatic parking technology is available for safe and quick parking operations without a driver, and improving the driving comfort while greatly reducing the probability of parking accidents. An automatic parking path planning and tracking control method is proposed in this paper to resolve the following issues presented in the existing automatic parking systems, that is, low degree of automation in vehicle control; lack of conformity between segmented path planning and real vehicle motion models; and low success rates of parking due to poor path tracking. To this end, this paper innovatively proposes preview correction which can be applied to parking path planning, and detects the curvature outliers in the parking path through the preview algorithm. In addition, it is also available for correction in advance to optimize the reasonable parking path. Meanwhile, the dual sliding mode variable structure control algorithm is used to formulate path tracking control strategies to improve the path tracking control effect and the vehicle control automation. Based on the above algorithm, an automatic parking system was developed and the real vehicle test was completed, thus exploring a highly intelligent automatic parking technology roadmap. This paper provides two key aspects of system solutions for an automatic parking system, i.e., parking path planning and path tracking control.

Virtual synchronous motor based-control of Vienna rectifier

Vienna rectifiers are widely used because of their advantages of high power-factor, low voltage stress on the power semiconductor switches, high power density, stable output voltage, low current harmonic content, and good economics. And gradually applied to the front stage AC/DC part of the electric vehicle charger. Traditional Vienna rectifier control methods include double closed-loop control, hysteresis current control, and Sliding mode variable structure control strategy, but all strategies usually regulate DC-Voltage and keep the unity power factor. However, if it is used for the interface part of the electric vehicle charger with frequent load switching, it is necessary not only to ensure the stability of the output voltage and low THD of the current, but also to be able to respond to the fluctuation of the voltage and frequency of the power system and improve the inertia and damping at the interface. Thereby, the stability of the power grid is improved to a certain extent, and fast-charging is ensured while being grid-friendly. Therefore, this paper proposes to apply the virtual synchronous motor control to the Vienna rectifier to improve the adaptability of the grid to the large-scale access of electric vehicles. Build the topology of the Vienna rectifier in simlink and the modulation method using SVPWM to build a complete model on the basis of VSM.

Bivariate grid-connection speed control of hydraulic wind turbines

The requirement for An electrical grid-connected wind turbine is that the synchronous generator speed is stable within a required speed range for the electrical grid. In this paper, a hydraulic wind turbine (HWT) system is considered, and the working principle and working conditions of the HWT are introduced. A novel speed control method is proposed in this paper, using both a proportional flow control valve and a variable displacement motor, which are adjusted in combination to control the speed of the HWT. By establishing a state space model of the HWT and solving the nonlinear system with a feedback linearization method, a bivariate tracking controller is constructed to realize accurate speed control under fluctuating wind speed and the load disturbance conditions. The effectiveness of the control method is verified by simulation, but experimental results highlight problems with the method. The theoretical controller is simplified to reduce sensitivity to measurement noise and modeling error. The control effect has been improved to some extent, but it is limited. Based on these results, combined with the sliding mode variable structure control method and the feedback linearization method to solve the problem of measurement noise and modeling error, and the effectiveness of the control law is finally verified experimentally. It lays a theoretical foundation for the practical application of HWT.

Research on Intelligent Control Algorithm for Automatic Drilling of Vehicle-mounted Rig

The adaptability of traditional PID, fuzzy PID and feedback linearization sliding mode variable structure control intelligent algorithm to automatic drilling is analyzed. The results show that the feedback linearization sliding mode variable structure control algorithm has more ideal response speed, control accuracy and robustness, which solves the nonlinear problem of the electro-hydraulic control system of the truck-mounted drilling rig and improves the tracking control accuracy of the system during automatic drilling.

Sliding Mode Control for Micro Turbojet Engine Using Turbofan Power Ratio as Control Law

The interest in turbojet engines was emerging in the past years due to their simplicity. The purpose of this article is to investigate sliding mode control (SMC) for a micro turbojet engine based on an unconventional compound thermodynamic parameter called Turbofan Power Ratio (TPR) and prove its advantage over traditional linear methods and thrust parameters. Based on previous research by the authors, TPR can be applied to single stream turbojet engines as it varies proportionally to thrust, thus it is suitable as control law. The turbojet is modeled by a linear, parameter-varying structure, and variable structure sliding mode control has been selected to control the system, as it offers excellent disturbance rejection and provides robustness against discrepancies between mathematical model and real plant as well. Both model and control system have been created in MATLAB® Simulink®, data from real measurement have been taken to evaluate control system performance. The same assessment is conducted with conventional Proportional-Integral-Derivative (PID) controllers and showed the superiority of SMC, furthermore TPR computation using turbine discharge temperature was proven. Based on the results of the simulation, a controller layout is proposed and its feasibility is investigated. The utilization of TPR results in more accurate thrust output, meanwhile it allows better insight into the thermodynamic process of the engine, hence it carries an additional diagnostic possibility.

Study on Fuzzy Neural Sliding Mode Guidance Law with Terminal Angle Constraint for Maneuvering Target

Aiming at the requirement that the guidance law should meet the minimum miss distance and the desired terminal angle at the same time, a sliding mode variable structure control method is introduced. In order to improve the fuzzy variable structure guidance law for maneuvering target attack effect, a neural network to the optimization design is carried out on the guidance law. The neural network is trained by the samples, which is under the condition of different error coefficient of angle, the coefficient of reaching law, and the coefficient of on-off item about target. Fuzzy neural sliding mode guidance law with terminal angle constraint can increase the performance of the large maneuvering target. In addition, on the basis of the traditional PC platform visual simulation system, a new guidance law simulation platform based on embedded system and virtual reality technology is formed. The platform can verify the validity of the guidance law.

Human-autonomous devices for weak signal detection method based on multimedia chaos theory

The detection of weak signals has been widely used in communication, radar and other fields. The detection of weak signals in the background of strong noise is an important research hotspot of modern information theory, and prompts people to explore and study new theories and new methods of weak signal detection. The device takes Holmes-type Duffing mapping as the research object, and uses the Lyapunov exponent as the criterion for chaos identification. The chaotic critical value of the equation is changed from chaotic state to periodic state. Whether it contains the detection algorithm of the target signal, the signal detection for the unknown frequency and the Holmes-type Duffing system is improved by the sliding mode variable structure control method in the control theory. The simulation results show that the improved chaotic Duffing system can effectively suppress the noise and detect the frequency of the weak signal through the power spectrum of the system.

Hierarchical sliding mode attitude control of a spherical underwater exploring robot

Aiming at the attitude control of the spherical underwater robot, the kinematics and dynamics of the underactuated attitude control adjusting system are analyzed, and its dynamics model is established. By using the differential homeomorphism transformation, the model was divided into two subsystems. Based on the advantages of sliding mode variable structure control, this paper adopts the hierarchical sliding mode variable structure method to design the sliding mode of different variables respectively, and then designs the sliding mode of the whole system. The presented control scheme can solve the coupling problem well. The controller has small overshoot and can well suppress chattering phenomenon. The simulation results show that the designed control law can make the system converge quickly and control the attitude of the underwater spherical robot effectively.

Control Strategy of the Vehicle's Active Steer by Wire

Zhang, Q.; Lin, W.; Wang, Y.; Wu, X., and Luo, Y., 2020. Control strategy of the vehicle's active steer by wire. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 355–360. Coconut Creek (Florida), ISSN 0749-0208.The Steer-By-Wire (SBW) system is free from the constraints of mechanical structure. Whether the system can work normally depends on the correctness of the control strategy. Therefore, this paper will study the control strategy of active steering by wire, which includes the design of ideal variable angle ratio control and active front wheel steering controller. Feed-forward control of ideal variable angle transmission ratio was determined based on constant yaw angular velocity gain. The sliding mode variable structure control theory is adopted. Based on the yaw rate deviation, the integral sliding surface is constructed, and the control strategy of equivalent and switching control is designed and active front wheel steering controller is completed. Through feedback control, the active control of the vehicle's front wheel angle is achieved, which improves the stability of the vehicle. Finally, through the typical test conditions, the designed control strategy was simulated and verified, and compared with the simulation results of uncontrolled vehicles. The results showed that the sliding mode controller of active SBW front wheel designed by yaw angular velocity feedback under the ideal variable transmission ratio can run stably under any working conditions and achieve good track following ability.

Trajectory tracking system of wheeled robot based on immune algorithm and sliding mode variable structure

An immune algorithm and a technique of sliding mode variable structure control (VSC) are proposed to achieve real-time and accurate control of wheeled robot in view of uncertainties for time-varying, strong coupling and nonlinear characteristics of wheeled robots, coupled with change of load and influence of external disturbance in traditional control algorithm based on classical control theory. First, the VSC parameters are adjusted online by the immune algorithm, which overcomes limitation that the parameters of reaching law need to be set in advance in conventional VSC. Secondly, the algorithm not only retains advantages of the traditional reaching law, but also effectively improves control quality and eliminates chattering of the system. The experimental results show that the control technique makes the wheeled robot move on sliding surface in an ideal way, for main concern of this paper is to provide an effective systemic for control of wheeled robot.

A general control strategy for planar 3-DoF underactuated manipulators with one passive joint

This paper presents a general control strategy based on the trajectory planning and tracking control for the planar 3-DoF underactuated manipulators with one passive joint at different position. According to the target position of the system, a set of target angles of all links are quickly obtained by using differential evolution algorithm. In order to achieve the control objective of the system from the initial position to the target position, we design the trajectory for each active link of the system, which is composed of two parts. The first part of the trajectory is designed according to the initial and target angle of the active link. The second part of the trajectory is designed based on the constraints between the passive joint and the active joints. Meanwhile, the parameters of the trajectories are optimized by the differential evolution algorithm to ensure that all links reach to their target angles eventually by tracking the designed trajectories. Then, the sliding mode variable structure controllers are designed to make all active links track their trajectories. The effectiveness of the proposed strategy is demonstrated through simulation results.

A Novel Sliding Mode Controller for Underactuated Vertical Takeoff and Landing Aircraft

Compared with other control methods, the biggest advantage of using sliding mode variable structure control method lies in its strong robustness which could be used to directly handle the strong nonlinear flight control system. However, this control method requires switching between different switching surfaces, which will inevitably cause buffeting problems, so that the energy consumption increases. Therefore, how to overcome this disadvantage to achieve the superior performance of sliding mode variable structure control method is the current research focus. This paper studies the trajectory tracking of under-actuated VTOL aircraft with three degrees of freedom and two control inputs under various coupling effects. By the input and coordinate transformation, the dynamic equation of the system is transformed into decoupled standard under-actuated form and the sliding mode controller is designed. Then Lyapunov stability theorem is used to derive sliding mode control law which could ensure that the system asymptotically converges to the given trajectory. The simulation has demonstrated the effectiveness of this method

Research on Semi-Active Vibration Control of Pipeline Based on Magneto-Rheological Damper

This paper proposes a scheme to control the low-frequency vibration of pipelines by using magneto-rheological (MR) vibration reduction technology. The state equation and the transfer function of the pipeline system are established, and its stability and the sinusoidal excitation response are analyzed. The prototype of MR damper is developed. The dynamic characteristics of MR damper are tested and the double-sigmoid model of MR damper is established. The two-state control, Proportion Integration Differentiation (PID) control and sliding-mode-variable-structure (SMVS) control methods of pipeline vibration using MR damper are analyzed comparatively, and the vibration control laws are deduced. The simulation analyses are carried out to predict the control effect of different pipeline vibration control algorithms. The verification tests through a semi-active measurement and control platform are carried out, and the feasibility and applicability of different pipeline vibration control strategies are analyzed. The test results show that the three kinds of pipeline vibration control methods based on MR damper can effectively control the pipeline vibration. Especially, SMVS control has the best vibration control effect, the pipeline amplitude drop and the acceleration drop can reach 22.31 dB and 16.34 dB respectively, while the amplitude attenuation rate and the acceleration attenuation rate can reach 92.34% and 84.77%, respectively.

Real-Time Implementation of Maximum Net Power Strategy Based on Sliding Mode Variable Structure Control for Proton-Exchange Membrane Fuel Cell System

Increasing in the net output power of proton-exchange membrane fuel cell (PEMFC) systems is an important aspect of improving the performance of PEMFC. In order to enhance the net output power of the PEMFC system, the maximum net power strategy of the PEMFC system is proposed. Since the PEMFC system is a nonlinear system with time delay and uncertainty, sliding mode variable structure control (SMVSC) based on the exponential approach law is applied to achieve real-time operation at the maximum net PowerPoint. This article has two main contributions. The first major contribution of this article is to obtain the maximum net power surface of the PEMFC by multivariate fitting and to design the maximum net power regulator. The second major contribution of this article is to design a sliding mode variable structure based on the exponential approach law. The Lyapunov function is used to converge the sliding mode surface to the defined neighborhood. The advantage of this structural design is that the approach speed is gradually reduced from a larger value, and the response time is shortened. The control effect of the maximum net power strategy based on SMVSC is verified by the PEMFC experimental platform.

Simulation and contrast study on flywheel energy storage control strategy for dynamic stabilization of power fluctuation in power grid

Flywheel Energy Storage System can not only effectively reduce the impact of energy fluctuation on the power grid, but also fully improve the utilization of distributed energy system because of its characteristics of energy storage and rapid charging. In this study, permanent magnet brushless DC motor is selected as flywheel motor for wind power system. The mathematical model of flywheel energy storage system in rectangular coordinate system is established. The double closed-loop simulation model of speed and current of flywheel energy storage system is built by using MATLAB/Simulink. In order to improve the control performance of flywheel energy storage system, three different control strategies, PID control, sliding mode variable structure control and ADRC control, were used to simulate the charging and discharging dynamic process of FESS. Considering the particularity of flywheel energy storage system as a limited energy storage unit, the controller parameters of three traditional control modes are adjusted effectively on the premise of keeping the parameters of the flywheel motor unchanged. The simulation results are compared from rotation rate and torque, and the advantages and disadvantages of three control strategies and the dynamic performance of flywheel energy storage system under different control strategies are analyzed.

Application of RBF Sliding Mode Control in Pump System for Electric Vehicle Heat Air Conditioning

Aiming at the characteristics of time-varying, time-delay and non-linearity of electric vehicle heat pump air-conditioning system, this paper presents a sliding mode control method based on RBF neural network. The RBF neural network can approximate the nonlinear function with arbitrary precision under certain conditions, and has strong self-learning and self-adaptive ability. Combining the RBF neural network with the sliding mode variable structure control not only has the anti-interference of the sliding mode control and the robustness to the parameter changes, but also effectively reduces the flutter caused by the sliding mode control. The simulation results show that the RBF neural network sliding mode control method can improve the system control accuracy, effectively weaken the chattering, and has good adaptability to the interference conditions.