Mode Variable Structure Control Algorithm Research Articles

Temperature Control of Methanol Distillation with High Gain Sliding Mode Variable Structure Based on SVM Multi-Classification

In the methanol distillation process, the production conditions are complex and changeable, and the temperature control requirements tend to be diversified. Traditional temperature control process requires manual adjustment of control parameters to adapt to different working conditions. In this paper, a sliding mode variable structure control algorithm based on support vector machine (SVM) multi-classification is proposed. By using the voting strategy of SVM multi-classification, the membership degree between the parameters η in the sliding mode control rate and the indexes of different working conditions is established, and the sliding mode control with a high gain observer is designed to control and adjust the actual temperature. The simulation of the whole temperature control system is realized by using the Simulink platform in Matlab, and the experimental results verify the effectiveness and correctness of the proposed control scheme.

Leveling Control of Hillside Tractor Body Based on Fuzzy Sliding Mode Variable Structure

To address the issues that arise when auto-leveling the vehicle body of a hillside tractor under complex working conditions, an auto-leveling control system was developed based on a newly developed hillside tractor and four-point body leveling mechanism. In this approach, leveling accuracy and stability were improved by adopting a sliding mode variable structure control algorithm based on fuzzy switching gain adjustment to achieve real-time dynamic auto-leveling control. To obtain curves of front and rear axle leveling displacement, speed, flow, pressure and body tilting angle during the leveling process, AMEsim/Simulink co-simulation was used to simulate and analyze the control system. The simulation results revealed that the tractor achieves a good leveling effect under complex working conditions in hilly and mountainous areas; the tractor can remain within a ±2° tilting angle range during the leveling process and can return to 0° after leveling, demonstrating good dynamic stability. To further assess the algorithm, a model of the system was submitted to live-testing on a custom-built auto-leveling test bench. Comparison of the test and simulation results revealed a close agreement between the two, indicating that the self-leveling control system and control algorithm developed in this study have high leveling accuracies. The results reported in this paper could provide assistance with or in reference to obtaining solutions to the problems of tractor body leveling in hilly and mountainous areas.

Expected position and attitude adjustment control method of coal mine roadway support robot

AbstractThis paper proposes an expected position‐attitude adjustment control method of coal mine roadway support robot (CMRSR) based on a real‐time position‐attitude detection system. Taking advantage of lateral adjustment mechanism and control method, the CMRSR has flexible maneuverability and high dynamic expected position‐attitude adjustment performance. It can guarantee stability and safety of the relative position‐attitude in time‐varying roadway environment in underground coal mines. First, the structural characteristics, hydraulic system characteristics, and kinematic characteristics of the CMRSR are considered, and the spatial mathematical relationship model on position‐attitude parameters and sensor data information, roadway environment dimensions, and CMRSR structural dimensions are established. In addition, the real‐time position‐attitude of the CMRSR with respect to the roadway is recognized by the position‐attitude detection system. Then, according to real‐time roadway environment and relative position‐attitude, the expected position‐attitude parameters are set, and the adjustment parameters and types of each lateral hydraulic cylinder are selected based on different deviated position‐attitude conditions. A position‐attitude adjustment controller is designed based on the sliding mode variable structure control algorithm to achieve precise position‐attitude adjustment of the CMRSR. In addition, the position‐attitude detection system is used to provide feedback control to maintain the relative position‐attitude of the CMRSR. Finally, the practical performance illustrates high effectiveness and feasibility of the proposed control method. The average error of distance can be controlled within ±30 mm, the average error of angle can be controlled within ±0.5°, and the adjustment time can be controlled within 20 s.

Sliding Mode Control of Digital Directional Valve Drive System Based on New Approach Rate

As an important development direction of hydraulic control components, static and dynamic properties of the spool drive mechanism determine the dynamic and static performance of the digital valve. For the study, permanent magnet synchronous motor and screw nut unit are used as the core drive mechanism for digital directional valve. To solve the practical problems that permanent magnet synchronous motor can not meet the performance requirements of digital directional valve in terms of spool position control accuracy and response speed, a sliding mode variable structure control algorithm with improved approach rate is registered, then the controller is devised and applied to position high-performance control of spool drive mechanism of digital directional valve. The simulation platform of digital directional valve drive system is built by MATLAB/Simulink software and compared with the control effect of traditional PI control algorithm. The emulation results show that can improved approach rate sliding-mode controller can be good for raise the speed of response and reinforce the trueness of the dynamic tracking accuracy of the system, has good dynamic response characteristics, and satisfies the performance requirements of digital directional valve.

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.

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.

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.

Research on load sensitive pressure control strategy of electro-hydraulic joint

In this paper, the mathematical and the state space model of the electro-hydraulic joint load sensitive pressure system are established. Combined with the perfect performance on optimization of RBF neural network and sliding mode variable structure control algorithm in the complex hydraulic system, this paper proposes a RBF neural network adaptive sliding-mode control algorithm. This paper designs a controller with the electro-hydraulic proportional overflow valve as the control object. The simulation results show that the RBF neural network adaptive sliding-mode controller has the advantages of high control accuracy, excellent dynamic response property and strong robustness in the complex electro-hydraulic system.

A Novel Anti-Swing Positioning Controller for Two Dimensional Bridge Crane via Dynamic Sliding Mode Variable Structure

To improve the control performance of anti-swinging and the orientation of two-dimensional bridge crane, a novel dynamic sliding mode variable structure control algorithm is presented here. The proposed controller can ensure global stability through improved design of sliding surface for the drive control force, and obtain the continuous driving control force in time domain, by using the Sigmoid function for switching function to suppress chattering. Experimental results demonstrated that it is effective on chattering suppression, swing reduction, and robust with various load qualities and friction resistances.

Active magnetic bearing system based on sliding mode control

A new sliding mode variable structure control algorithm suitable for active magnetic bearing is proposed, which is widely used for nonlinear control system. The model and controller is designed, simulation and experimental parts are also made, according to the switching function and the sliding mode control law. The current of electromagnet is adjusted to realize stable levitation of the rotor. The experimental result shows that the sliding mode variable structure controller is an effective way for magnetic bearing control, and the active magnetic bearing system is a highly nonlinear and advanced control method that can reduce the setting time and the cost.

Research on Straight Line Stability Control Strategy of Four Wheel Drive Vehicle Based on the Sliding Mode Variable Structure Control and Optimization Algorithm

Abstract After the reference of straight line stability control strategy of four-wheel drive vehicle, this paper proposes a control algorithm combining the sliding mode variable structure and optimization control method. The control algorithm is mainly divided into the upper generalized moment calculation based on the sliding mode variable structure controller and the lower torque distribution controller based on the optimization algorithm, also including the slip rates controller based on PID algorithm to ensure the straight line stability control. This paper establishes the combined model based on the CarSim and MATLAB, and tests to verify the validation of the control strategy through the four-wheel drive vehicle test-bed based on RT_LAB. The simulation and experimental results show that when the tire-road friction coefficient is low, the control strategy can not only make the vehicle tire slip rates stay near the optimal slip ratio, at the same time through the yawing moment adjustment, ensure the yaw angle of vehicle not beyond 0.5 deg/s, so the method can effectively ensure the straight line stability of four wheel drive vehicle.

The Sliding Mode Control about ASR of Vehicle with Four Independently Driven In-Wheel Motors Based on the Exponent Approach Law

Acceleration slip regulation control system is a new active safety technology. In this paper, through the research of the four-wheel independent drive electric vehicle, a sliding mode variable structure control algorithm based on exponent approach law is proposed, which is applied to the ASR system. This paper establishes a seven DOFs vehicle dynamics model, tests whether the ASR control strategy is efficient on the poor condition road. The simulation results show that the vehicle acceleration performance improvement rate increases by 43.5% and 58.5% with the control strategy. During the two simulation processes, the results indicate that the sliding mode variable structure control algorithm applied to ASR system has a good adaptation to good and slippery roads. The algorithm can greatly improve the four-wheel independent drive electric vehicle's acceleration performance.

Based on Sliding Mode Variable Structure Current Controller for Induction Motor Vector Control Technology

In this paper, according to the induction motor in rotating coordinate system mathematical model, established based on rotor flux oriented vector control model and realized flux linkage and torque decoupling. In order to solve the current high coupling, designed the sliding mode variable structure control algorithm of current controller. Based on the sliding mode variable structure control algorithm achievable conditions and Lyapunov stability theorem, proved that the sliding mode of accessibility and stability, determined the sliding model parameters. The simulation results show that the sliding mode variable structure control of induction motor vector control system, can reduce the torque ripple and the speed overshoot and improve the system parameter perturbation and external disturbance signal robustness.

Analysis and Design of Automatic Steering Sliding Mode Control

A kind of intelligent vehicle–road model based on look-ahead reference system is established. According to the state equation, a novel sliding mode variable structure control algorithm is proposed. The sliding function is defined using pole placement technology, while the trending motion is determined by exponential reaching law. Accordingly, the effect of poles and reaching law parameters to close loop control system is analyzed in depth in order to design a good performance automatic control system. Finally, the developed sliding mode controller is validated by simulation study. Simulation results show that the designed controller has good performance in road tracking scenario.

Active vibration control of a flexible beam using a non-collocated acceleration sensor and piezoelectric patch actuator

In this paper, the design of an acceleration sensor based active vibration control for a cantilever beam with bonded piezoelectric patches is studied. The problem of phase hysteresis and time delay caused by the non-collocated sensor/actuator pairs is considered. The system's dynamic model considering the non-collocated placement of the acceleration sensor and the piezoelectric patch actuator is derived. The phenomenon of phase hysteresis and time delay degrades the performance of the control system, or even induces instability. To solve the problem, an acceleration sensor based proportional feedback control algorithm and a sliding mode variable structure control algorithm with phase shifting technology are proposed, for suppressing the first two bending modes vibration of the beam. The stability of the proposed controllers was theoretically analyzed. The modal frequencies, phase hysteresis loops and phase lag values due to non-collocated placement of the acceleration sensor and the piezoelectric patch actuator are experimentally obtained, and the phase lag is compensated by using the phase shifting technology. Experiments are conducted to compare the above two active vibration control algorithms. Experimental results demonstrate that the presented acceleration sensor based control methods are effective.

Experimental researches on sliding mode active vibration control of flexible piezoelectric cantilever plate integrated gyroscope

The flexible appendages of spacecrafts in aerospace applications demand to be lighter and larger. Thus, they are susceptible to excessive vibration response due to external disturbances or attitude maneuvering. Some of the flexible appendages are cantilever plate structures, such as solar panels and plate shape antennas. Usually, the coupled bending and torsional vibration of cantilever plate will be caused. To decouple the bending and torsional vibration for measuring and driving, gyroscope and PZT patches are used as sensors and actuators by utilizing optimal placement. The motion of equation of the presented piezoelectric plate system is derived. And a kind of discrete-time sliding mode variable structure control (VSC) algorithm is proposed to suppress vibration of the flexible plate. The experimental comparison studies are conducted. The experiments demonstrate that the proposed methods can suppress vibration significantly for cantilever plate.