scholarly journals AUTO LOAD-LEVELLING CONTROL OF A LARGE SPRAYER CHASSIS USING THE SLIDING MODE METHOD

2021 ◽  
pp. 65-80
Author(s):  
Chen Yu ◽  
Wu Jun ◽  
Zhang Shuo ◽  
Chen Jun ◽  
Xia Hui ◽  
...  
Keyword(s):  
Working Conditions ◽  
Control Method ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Good Control ◽  
Variable Structure ◽  
Wheel Load ◽  
Structure Control ◽  
Air Suspension ◽  
Sliding Mode Variable Structure

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.

scholarly journals Experimental study on sliding mode variable structure control of active vibration isolation system of floating raft under multiple excitations

2018 ◽  
Vol 37 (4) ◽  
pp. 1176-1187
Author(s):  
Xianglong Wen ◽  
Kang Yi ◽  
Chunsheng Song ◽  
Jinguang Zhang
Keyword(s):  
Vibration Isolation ◽  
Control Method ◽  
Sliding Mode ◽  
Reference Signal ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Vibration Signal ◽  
Isolation System ◽  
Structure Control ◽  
Sliding Mode Variable Structure

The frequency components of vibration signal in vibration isolation system under multiple excitations are quite complex.Self-adaptive feedforward control method based on Least Mean Square algorithm has strict requirements for reference signal, which results in a certain restriction on its practical application. Sliding mode variable structure control method needs neither complicated reference signal nor accurate mathematical model. It has the strong robustness for external disturbance and system parameter perturbation, and the physical implementation is simple. To this end, application of sliding mode variable structure control method is studied. First, mathematical model of the control channel through system is established for identification. Second, the discrete sliding mode variable structure controller based on state-space model is designed to carry out simulation and experiment. The experimental result indicates that root mean square value of vibration signal after control is decreased by 57.90%, of which the amplitudes of two main frequency components 17 and 25 Hz reduce by 42.66 and 72.71%, respectively. This shows that sliding mode variable structure control is an effective control method for active vibration isolation of floating raft under multiple excitations.

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

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 221
Author(s):  
Guishan Yan ◽  
Zhenlin Jin ◽  
Tiangui Zhang ◽  
Penghui Zhao
Keyword(s):  
Control Strategy ◽  
Position Control ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Control Valve ◽  
Good Control ◽  
Variable Structure ◽  
Structure Control ◽  
Sliding Mode Variable Structure ◽  
Valve Control

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.

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

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Flight Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Superior Performance ◽  
Sliding Mode Controller ◽  
Structure Control ◽  
Sliding Mode Variable Structure

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

Control of chaos in vehicle lateral motion using the sliding mode variable structure control

2018 ◽  
Vol 233 (4) ◽  
pp. 776-789 ◽  
Author(s):  
Wuwei Chen ◽  
Rongyun Zhang ◽  
Linfeng Zhao ◽  
Hongbo Wang ◽  
Zhenya Wei
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Chaotic Behavior ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Operating Conditions ◽  
Lateral Motion ◽  
Lateral Stability ◽  
Structure Control ◽  
Sliding Mode Variable Structure

A 3-degree of freedom (DOF) nonlinear model including yaw, lateral, and roll motions was constructed, and a numerical simulation of chaotic behavior was performed using the Lyapunov exponent method. The vehicle motion is complex, manifesting double-periodic, quasi-periodic, and chaotic phases, which negatively affects the vehicle lateral stability. To control this chaotic behavior, a controller was designed based on the sliding mode variable structure control (SM-VSC) method. To decrease chattering and further improve lateral stability of the vehicle under extreme operating conditions, the adaptive power reaching law was realized by using a fuzzy control method. The performance of the SM-VSC system was simulated by using Matlab/simulink. The simulation results including the uncontrol, SM-VSC control, and adaptive-reaching SM-VSC control were compared, which demonstrated that the adaptive-reaching SM-VSC control method is more effective in suppressing the chaotic phase of the vehicle lateral motion. The approach proposed in this paper can significantly improve a vehicle’s lateral stability under extreme operating conditions.

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