Sliding Mode Variable Structure Control Research Articles

Multi-Degree-of-Freedom Manipulator Joint Trajectory Tracking Control Method Based on Decision Tree

For industrial-grade manipulators, the study of trajectory tracking control issues provides an important guarantee for accurate and safe work. Therefore, the trajectory control input driving torque can meet the requirements of the robot arm to accurately track a given target trajectory, and the process of building a decision tree is a process of dividing the feature space. For a given training data set, a set of if-then is summarized the rule of. Based on this, this paper launches the research of multi-degree-of-freedom manipulator joint trajectory tracking control method based on decision tree. Based on the established kinematics and dynamics model of the manipulator, this paper uses a proportional-integral-derivative (PID) sliding mode controller based on the sliding mode surface of the manipulator to perform the trajectory tracking control of the end of the manipulator, and the simulation results of the improved sliding mode control are compared with the simulation results of the improved sliding mode control. The simulation results of the PID controller and the traditional sliding mode controller are compared. This paper finally verifies the effectiveness of the proposed new sliding mode controller based on the expanded state observer through the experimental platform. The speed and chattering problems of the trajectory tracking at the end of the manipulator are better than those of the controller on the experimental platform. Finally, this paper adopts the sliding mode variable structure control strategy combining the double-power reaching law and the improved terminal sliding mode surface to study the trajectory tracking control of the planar two-degree-of-freedom manipulator.

Control of a Digital Galvanometer Scanner Using a Discrete-Time Sliding-Mode Variable-Structure Controller Based on a Decoupled Disturbance Compensator

Laser processing plays an important role in industrial manufacturing, in which a galvanometer scanner (GS) functions as the core component of the laser processing equipment. With the development of the digital system, the GS based on the digital system finds a broader range of potential application. In order to address the slow step-responses of a GS with disturbance and parameter perturbation, the mathematical model of the motor of the GS is derived and a discrete-time sliding-mode variable-structure controller (DSVC) based on a decoupled disturbance compensator (DDC) (DSVC+DDC) is designed. The step-response performance of a GS is the key factor affecting the quality evaluation of laser processing. Experiments are conducted on the step responses of the motor of the GS on a digital experimental platform. The experiment results show that when guaranteeing a steady-state error within 20 urad and an overshoot of less than 5%, the rise time for step-responses in 1% and 10% of the whole stroke is 1 and 2 ms, decreasing by 23% and 58% compared with the reference performance index, which indicates the effectiveness of the proposed method. The proposed approach can not only compensate for the external disturbance online and improve the step-response speed of the GS, but also relax the traditionally assumed limit of the upper bound of external disturbance to the limit of the change rate of external disturbance, which reduces the difficulty of a practical application. This method has great significance for further applications in high precision machining.

Torque vectoring control system for distributed drive electric bus under complicated driving conditions

PurposeThe purpose of this study is to propose a torque vectoring control system for improving the handling stability of distributed drive electric buses under complicated driving conditions. Energy crisis and environment pollution are two key pressing issues faced by mankind. Pure electric buses are recognized as the effective method to solve the problems. Distributed drive electric buses (DDEBs) as an emerging mode of pure electric buses are attracting intense research interests around the world. Compared with the central driven electric buses, DDEB is able to control the driving and braking torque of each wheel individually and accurately to significantly enhance the handling stability. Therefore, the torque vectoring control (TVC) system is proposed to allocate the driving torque among four wheels reasonably to improve the handling stability of DDEBs.Design/methodology/approachThe proposed TVC system is designed based on hierarchical control. The upper layer is direct yaw moment controller based on feedforward and feedback control. The feedforward control algorithm is designed to calculate the desired steady-state yaw moment based on the steering wheel angle and the longitudinal velocity. The feedback control is anti-windup sliding mode control algorithm, which takes the errors between actual and reference yaw rate as the control variables. The lower layer is torque allocation controller, including economical torque allocation control algorithm and optimal torque allocation control algorithm.FindingsThe steady static circular test has been carried out to demonstrate the effectiveness and control effort of the proposed TVC system. Compared with the field experiment results of tested bus with TVC system and without TVC system, the slip angle of tested bus with TVC system is much less than without TVC. And the actual yaw rate of tested bus with TVC system is able to track the reference yaw rate completely. The experiment results demonstrate that the TVC system has a remarkable performance in the real practice and improve the handling stability effectively.Originality/valueIn view of the large load transfer, the strong coupling characteristics of tire , the suspension and the steering system during coach corning, the vehicle reference steering characteristics is defined considering vehicle nonlinear characteristics and the feedforward term of torque vectoring control at different steering angles and speeds is designed. Meanwhile, in order to improve the robustness of controller, an anti-integral saturation sliding mode variable structure control algorithm is proposed as the feedback term of torque vectoring control.

Flexible spacecraft attitude maneuver via adaptive sliding mode control and mixed component synthesis vibration suppression

<p indent=0mm>A mixed component synthesis vibration suppression method (MCSVS) is proposed to solve the problem of residual vibration of flexible attachments, which is difficult to control effectively. Theorems and inferences are provided, and their proofs are performed. Aiming at the problem that the attitude controllers cannot suppress the vibration of flexible attachments in spacecraft attitude maneuver, a strategy combining the MCSVS method with an attitude control method is proposed. Considering the existence of moment of inertia variation and external disturbance of spacecraft, an adaptive sliding mode variable structure controller is proposed. By introducing a sliding mode boundary layer and the update rate of the torque parameter, the disadvantages of torque chattering and parameter dependence are eliminated. Finally, the joint application of the MCSVS method and the adaptive variable structure controller is realized with the assistance of piezoelectric intelligent materials. Simulation results show that the control strategy without the MCSVS method cannot suppress the vibration of flexible attachments. After combining the MCSVS method with the attitude control method, the residual vibration is well controlled, and the attitude accuracy is improved.

Sliding Mode Variable Structure Chaos Control for Propulsion Motor of Deep Sea Robot

As the deepwater robot’s dynamic thruster system, the brushless thruster system’s performance will influence the whole system reliability, stabilization, safety. The brushless thruster system will appear chaotic phenomena when its system structure and parameter match badly. The phenomena will lead the deepwater robot out of control, even involved by ocean wave. Aiming the chaos phenomenon of propulsion motor of deepwater robot, this paper proposes the application of sliding mode variable structure control theory to chaos control. The sliding mode variable structure chaotic control of brushless propulsion motor for deep-sea robot is designed, and the controller is designed. The feasibility and effectiveness of the chaotic control are simulated, analyzed and verified. The research result proves that, the gradation sliding mode variable structure using in control of the deepwater robot thruster motor chaotic motion are feasible and effective, i.e. the thruster motor can research the stabilization state from chaotic state and the procedure of control is related to the controller structure, parameter, and control time. And for the example system, the exponent gradation sliding mode variable stature control effect is the better.

基于滑模控制的大型喷雾机底盘自动调平方法研究

When a sprayer travels on a ramp or a rough road, the load exerted on each wheel changes. If an unbalanced wheel load is maintained for long periods of time, the wheels may slip, the sprayer’s manoeuvrability is affected, and a rollover accident may occur. In this study, the air suspension of a self-propelled sprayer chassis was investigated, and the potential load imbalance conditions of the sprayer suspension were analysed. A mathematical model of the inflation/deflation of the suspension was established based on air nonlinear thermodynamics and vertical dynamics theory and a ¼-scale vertical dynamics model of the sprayer chassis was developed. A control strategy to balance the sprayer’s wheel load was developed. Considering the nonlinear characteristics of the air suspension, a sliding mode variable structure control method was used to balance the wheel load. Simulation experiments were conducted under different working conditions. The simulation results showed that the sliding mode variable structure control provided good control response and precision. The proposed auto load-levelling controller was tested under different working conditions, including different roll and pitch angles and navigating a rough road; the controller successfully changed the load on each spring to ensure that the sprung mass of the suspension was equal and the wheel load was balanced. The results of this study provide reference information for auto load-levelling control of large sprayers.

A stability control way of bus voltage in DC microgrid with constant power load

During the operation of the independent DC microgrid, the bus voltage will fluctuate with the random changes of the load and source. To maintain the stability of the bus voltage, a control strategy needs to be introduced in the DC microgrid. According to the bus voltage change of DC microgrid, this paper establishes a large‐signal mathematical model of DC microgrid with constant power load. Taking the bidirectional DC‐DC converter as the control object, a sliding mode variable structure controller based on the washout filter is introduced, and the bus voltage is stabilized at the desired voltage value through the selection of control parameters. The simulation experiment results show that the control strategy proposed in this paper can effectively restrain the fluctuation of the bus voltage under the condition of random changes of the load and source and has strong robustness. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Fuzzy and Sliding Mode Variable Structure Control of Vehicle Active Steering System

Background: The safety of vehicles has been valued throughout the world, whether it is now or in the future, the automobile safety issue is the hotspot and focus of the research by experts and scholars both at home and abroad. The continuous increase of car ownership not only brings convenience to people's lives, but it also poses a threat to people's lives and security of the property. Objective: Vehicle active safety system is the hotspot of current research and development as it plays an important role in automobile safety. Through the analysis of patents and references, we aim to understand the development of an active steering system. In order to improve the development efficiency of the active steering system, the paper proposes a feedback control method of the front-wheel angle. Methods: Based on yaw velocity and center of a mass side angle, the Active Front Steering (AFS) model is established respectively by fuzzy control and sliding mode control under the establishment of seven degrees of freedom vehicle dynamics model and the Dugoff tire model. Results: The simulation results show that both the control algorithm of sliding mode control and fuzzy control can improve the handling stability of vehicle steering on high adhesion coefficient road surface. On the low adhesion coefficient road, the control effect of slide mode control is more ideal while fuzzy control caused larger oversteer. Conclusion: The simulation results show that the control effect of sliding mode is superior to fuzzy control.

Research on Inverter Turbine System Based on Sliding Mode Variable Structure Control

This paper uses modern control theory, control the primary inverted tank, established on the basis of state space method, using state feedback to make feedback control. Then use the powerful numerical computing power and data visualization capability of MATLAB software, and the inverted swing system is used to control the simulation. The system simulation results show that the sliding mode variable structure is used to control the inverted shelter, the system is more stable, robustness Good, thereby proves the effectiveness of the sliding mode variable structure controller.

Fuzzy sliding mode variable structure control of a high-speed parallel PnP robot

This paper presents the analysis and experimental evaluation of robot dynamics and control for a four-limb parallel Schönflies-motion generator dedicating to fast pick-and-place operations, with a different topological architecture from its counterparts for efficient use of shop-floor space. The concise equation of motion is built with principle of virtual work to characterize the robot dynamics, which is integrated into the model-based control design. Fuzzy sliding mode variable structure control is adopted for the design of control scheme, aiming at buffeting suppression of the actuated joints and minimization of pose errors of robot end-effector. Numerical simulations are carried out along a trajectory of an industrial standard testing cycle to evaluate the performance, which is validated experientially by observing the joint dynamics. The results show the effectiveness of the developed dynamic control scheme for fast parallel pick-and-place robots.

Sliding Mode Variable Structure Control of the Steerable Drilling Stabilized Platform Based on Disturbance Observer

A sliding mode variable structure control based on disturbance observer (SMVSCDOB) has proposed to tackle the uncertainty caused by friction in the stabilized platform on the rotary steerable drilling. Disturbance observer (DOB) is used to estimate the uncertainty in stabilized platform, and the estimated value is compensated by sliding mode variable structure control (SMVSC) to improve the control accuracy. The simulation experiment of control system is carried out with MATLAB, comparing the SMVSCDOB control method with proportional integral derivative (PID), PID+DOB, SMVSC. The simulation results show that the proposed method SMVSCDOB can better track the tool face angle, reduce the system error, suppress the friction interference, and enhance robustness of the system.

Attitude control of self-balancing vehicle based on sliding mode variable structure control

The two wheeled self balancing vehicle belongs to a typical nonlinear system. Aiming at the problem of attitude control stability of two wheeled self-balancing vehicle. A new sliding mode reaching law of integral sliding mode variable structure control was proposed. The feasibility and effetivenes of the controller are proved by theory and experiment. The experiment results show that the designed controller has remarkable advantages of steady state characteristic,fast dynamic response and strong robustness to external disturbance to compared with traditional PID controller.

Cooperative control method of multi-missile formation under uncontrollable speed

Under the missile speed is uncontrollable, a design method of multi-missile formation flight controller based on the sliding mode variable structure control theory and adaptive dynamic surface control theory is proposed. Firstly, according to the relative position of the leader and the follower in the inertial frame, the tracking error model for the relative position and the expected relative position between the leader and the follower is obtained, and the multi-missile formation control system in the inertial coordinate system is obtained. Secondly, in order to obtain the expression of the formation control system in the ballistic coordinate system, the acceleration of the missile in the ballistic coordinate system is converted to the inertial coordinate system. Combining with the tracking of the relative position and the desired relative position of the leader and the followers, we can obtain the simplified error model for the formation control system. Then the sliding mode variable structure control theory and the adaptive dynamic surface control theory are used to design the formation controllers for the leader and follower missiles respectively, and the stability of the present controller is analysed via the Lyapunov stability theory. Finally, the designed formation controllers are used for the leader and follower missiles to simulate the parameters. The results verify the feasibility and effectiveness of the present method.

Sliding-mode control of gantry crane system with recursive least square parameters identification

In this paper, a set of PDE-ODE (partial-differential-equation and ordinary-differential-equation) are derived to describe the dynamic characteristics of overhead gantry crane system. The control objective in this paper is to move the payload suspended by the cable below the trolley to the desired position through the motion of trolley with a vibration suppression. A sliding-mode variable structure controller (SMC) under dead zone disturbance is derived and the stability of the closed-loop system is proved. At the same time, the key parameters in the model can be identified online by recursive least square (RLS) algorithm for covering the cases of varying parameters such as the mass of payload. Finally, a numerical simulation is given to verify the effectiveness of the proposed controller combined with the parameter identification in this paper.

Research On the Application of Superconducting Magnetic Energy Storage in the Wind Power Generation System For Smoothing Wind Power Fluctuations

As the output power of wind farm is fluctuating, it is one of the important ways to improve the schedule ability of wind power generation to predict the output power of wind farm. The operation mode of tracking planned output takes the planned value issued by the grid dispatching as the control basis of wind power generation. This operation mode is easy to control, which not only meets the needs of power grid dispatching, but also improves the reliability and controllability of new energy generation. This paper introduces the traditional PI control strategy of SMES and combines the advantages of SMES and the characteristics of application scenarios, and introduces sliding mode variable structure control into SMES. Through simulation and comparison of two different control modes, it is verified that SMES adopting sliding mode variable structure control have the advantages of fast response speed and strong robustness, which can make the wind farm output stable power according to the planned value.

Design of Quad-rotor Controller Based on Fractional Order Sliding Mode Control

According to the chattering problems of traditional sliding mode index exponential reaching law, this paper proposes a fractional order sliding mode index exponential reaching law control strategy, which is applied to the quad-rotor helicopter attitude control. Combined the theory of fractional order calculus and sliding mode variable structure control theory, the fractional order sliding mode controller is designed. The method of lyapunov analysis proves that this controller can make the system asymptotically stable. Simulation and experiments show that the proposed fractional order sliding mode control system not only undermines the chattering of traditional sliding mode exponential reaching law but also reduces the adjusting time and control margin of the system.

Scanning control based on real-time contact force feedback for ultrasonic thickness measurement

An effective contact force control strategy is of great significance for accurate and stable ultrasonic thickness on-machine measurement. However, it is difficult to adjust the contact force dynamically due to the uncertainty of the geometric characteristics of the measured workpiece. In this paper, a contact force control method based on the combination of adaptive impedance controller and sliding mode variable structure position controller is proposed. First, the control process with the force tracking impedance control and a normal contact force calculation model is established. Then, a force-position conversion model and a sliding mode variable structure controller are proposed. Further, a simulation with a typical S-shaped measured surface is given to show that the algorithm for controlling contact force can achieve good real-time tracking performance and has stronger robustness than traditional methods. Finally, an arc-shaped aluminum alloy thin-wall part thickness is sampled along the scan trajectory to verify the effectiveness of the algorithm. The experimental results show that the proposed algorithm for controlling contact force can quickly adjust the measuring device to the target position and maintain the stability of the normal contact force to ensure the accuracy of ultrasonic thickness on-machine measurement.

Review of Vehicle Active Safety Systems and Their Coordinated Control

Background:It is obvious that the safety concern associated with a vehicle is greatly valued by all, whether it is now or in the future, the automobile safety issue is the hotspot and the focus of the research by experts and scholars. The continuous increase in car ownership brings convenience to people's life and also poses a threat to people's life and property. Vehicles’ active safety system is the hotspot of current research and development, which plays an important role in automobile safety. Firstly, the vehicle’s active safety technology and its development are introduced. Then, a review is carried out examining the Anti-Lock Brake System (ABS), the Electronic Brake force Distribution (EBD/CBC), the Brake Assist System (BAS/EBA/BA), the Traction Control System (TCS/ASR), the Vehicle Stability Control (VSC/ESP/DSC), etc. At present, there are many patents on the control of each subsystem, but few patents on the integrated control for the active safety of vehicles.Objective:The main contents of this paper are as follows: the control strategies and methods of different active safety systems, the strategies to improve the stability of a vehicle control system and ensure the effectiveness of active safety system control. It provides a reference for the development of active safety control technology and patent.Methods:Through the analysis of different control algorithms and control strategies of Anti-lock and braking force distribution systems, it is pointed out that the switching of EBD/ABS coordinated control strategy according to slip rate can make full use of slip rate and road adhesion coefficient to improve the safety of the system. For the BAS, the slip problem is solved through the combination of the Mechanical Assistant Braking System (MABS) and Electronic Braking Assistant (EBA) system by measuring the distance and the speed of the vehicle ahead. The optimal slip rate control is realized by different control algorithms and control strategies of the traction control system. It is pointed out that the adaptive fuzzy neural controller should be used to control the yaw angular velocity and centroid side angle of the Electronic Stability Program (ESP), which has a good effect on maintaining vehicle stability. A sliding mode variable structure controller combined with constant speed control and law control is used to control the yaw moment.Results:Through the coordinated control strategy of EBD/ABS, the slip rate and road adhesion coefficient were fully utilized by switching according to the slip rate. The problem of the sliding slope was solved by MABS with EBA system. The ESP should use an adaptive fuzzy neural controller to control the yaw angular velocity and centroid side angle, and adopt the joint sliding mode variable structure controller which combines the ABS control and the yaw moment control. Through the optimal control theory, the coordinated control of each subsystem can significantly improve driving stability, riding comfort, fuel economy and so on.Conclusion:This study adopts different control strategies and control algorithms for different active safety control systems and makes full use of the tire-road friction coefficient and slip ratio optimal slip ratio. These focus on accurate control of control variables such as yawing angular velocity, centroid side-slip angle, yawing moment and finally ensure the vehicle braking stability, robustness of the controller and the lateral stability of the vehicle.

Position Control Study on Pump-Controlled Servomotor for Steam Control Valve

In steam turbine control and actuation, the steam control valve plays a key role in operability and reliability. The electrohydraulic regulating system for the steam control valve, usually called the servomotor, needs to be reliable and high performing under nonlinear excitation interference in actual conditions. Currently, electrohydraulic servo valve control technology is widely used in servomotors. Although this technology has good control performance, it still has some technical defects, such as poor antipollution ability, low energy efficiency, large volume size, and limited installation space. Aiming at the abovementioned technical shortcomings of electrohydraulic servo valve control technology, a servomotor-pump-hydraulic cylinder volume control scheme is proposed in this paper, forming a pump-controlled servomotor for the steam control valve. By analyzing the working principle of the pump-controlled servomotor position control in the steam control valve, the mathematical model of a pump-controlled servomotor for the steam control valve is established. The sliding mode variable structure control strategy is proposed, and the variable structure control law is solved by constructing a switching function. To verify the performance of the proposed control method, experimental research was conducted. The research results show that the proposed sliding mode variable structure control strategy has a good control effect, which lays the theoretical and technical foundation for the engineering application and promotion of pump-controlled servomotors for steam control valves and helps the technical upgrade and product optimization of steam turbines.

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.