A radial basis function neural network PID controller under fuzzy rules (FUZZY-RBF-PID) was designed for the electro-hydraulic position servo system under the influence of uncertain factors such as load mutation, and load stiffness change. Firstly, the mathematical model of the system is established, and the frequency domain and time domain analysis of the system are carried out. Secondly, based on the analysis results, a radial basis function (RBF) neural network PID controller is designed, and fuzzy rules are innovatively used to adjust the learning rate of PID parameters in the RBF neural network learning algorithm in real time. Thirdly, the simulation results show that under the action of the FUZZY-RBF-PID controller, the unit step response of the system has high steady-state accuracy, fast response speed, and under the condition of large load stiffness, the system can recover to the steady-state value faster after being disturbed. At the same time, when the input signal is the sinusoidal signal of 10 HZ, the system under the action of the FUZZY-RBF-PID controller has no obvious phase lag phenomenon, and the tracking error is minimal. The proposed method can effectively improve the comprehensive performance of the electro-hydraulic position servo system under the influence of uncertain factors.

Background: Proportional-integral-differential (PID) controller is widely used in the engineering field because of its simple structure, high control accuracy, and easy operation. Different patented PID control technologies have their own advantages, disadvantages, and application scenarios. Objective: By analyzing and discussing the improved PID control techniques in the electrohydraulic servo system, some valuable conclusions have been drawn to predict the future research and development of PID control techniques. Methods: The improved PID control techniques applied to electro-hydraulic servo systems are classified into three categories: PID parameter tuning technology, PID parameter online adjustment strategy and compound control strategy combined with PID algorithm. Results: By comparing the principles and characteristics of the above techniques, the advantages, disadvantages and application scenarios of each are analyzed, and the further development of PID control technology is discussed. Conclusion: Based on the characteristics of electro-hydraulic servo systems, the further combination of the three types of technology can make up for the shortcomings of PID algorithms to form a control strategy with high control accuracy, high robustness, and fast response speed.

Background: The nonlinear problem of the electro-hydraulic servo system directly affects the system accuracy, response speed and other indicators, and the resulting problems of control inaccuracy and response delay urgently need to be solved. Method: This article provides an overview of the working principle of electro-hydraulic servo systems, reviews the development history of electro-hydraulic servo systems, and summarizes the current research difficulties and latest patents of electro-hydraulic servo systems from the characteristics of active and passive loading systems,electro-hydraulic servo system multi flexibility characteristics, gap nonlinearity,parameter time-varying characteristics,mathematical modeling,force tracking accuracy control strategy, etc. Result: A large number of scholars have proposed the latest optimization strategies to address the nonlinear problems in various aspects of the electro-hydraulic servo system, effectively improving the control accuracy and static and dynamic characteristics of the electro-hydraulic servo system. Conclusion: By summarizing the latest progress in the study of nonlinear problems in various links of electro-hydraulic servo systems, it has played a guiding role in their future improvement and optimization strategies.

PID control is the most common control method used in process contro1. Fractional-order PI^¿D^ß control is the generalization and development of the integer-order PID contro1. Compared to integer PID controller, fractional PI^¿D^ß controller has more advantages than integer PID, but the scarcity of tuning methods of the fractional PID is still a problem to be resolved. Based on filter algorithms and adopting the Matlab/Simulink software, a global search optimization method with bacterial foraging oriented by particle swarm optimization was applied for the optimization of the five parameters of fractional controllers, including orders of fractional calculus. Simulation results show that it is an effective tuning strategy. It also can be seen that better control quality can be achieved by using fractional PI^¿D^ß controller for nonlinear systems.

The scanning vibration mirror system drives the scanning mirror fixed to it through the oscillation of the motor shaft, so as to control the reflected light to form a dynamic variable light path. The vibration mirror scanning system has higher controllability than the fixed optical path system and has been widely used.In this dissertation, after establishing the models of the core components of the scanning vibration mirror system, the mathematical model of the whole system is established.On this basis, simulation and theoretical analysis show that the system has some shortcomings, such as small bandwidth, low dynamic tracking accuracy, and the comprehensive dynamic performance of the system is easily affected by the input of external interference branches. A series correction controller and three closed-loop controller are designed for the above problems, respectively, and the control effects of the two controllers on the scanning vibration mirror system are studied through simulation experiments. By comparing the output response results of the system under the action of sinusoidal signals of different frequencies, it can be seen that the comprehensive effect of the three closed-loop controllers is better. Under the action of step signals, the overshoot of the three closed-loop correction controller correction system is 21.5% higher than that of the series controller correction system, the adjustment time is 82.7% less, and the steady-state error is significantly smaller. Therefore, it indicates that the three closed-loop correction system has good rapidity and steady-state accuracy.

Aiming at the sticking phenomenon between the valve core and the valve sleeve when the valve core moves, and to solve the problem that the torque required to drive the valve core to rotate is large, the fluid–solid coupling simulation analysis of the valve core is carried out in this study, and then the valve core structure of the valve core is improved and its parameters are optimized based on the bird colony algorithm. The combination structure of the valve sleeve and valve core is studied, and the fluid–solid coupling model is established by Ansys WorkBench, and the static structure simulation analysis of valve sleeve and valve core before and after structural improvement and parameter optimization is performed. The mathematical models of triangular buffer tank, U-shaped buffer tank and combined buffer tank are established, and the structural parameters of the combined buffer tank are optimized by bird swarm optimization. The results demonstrate the triangular buffer tank has good depressurization effect but great impact, the pressure of the U-shaped buffer tank is stable and gentle but the depressurization effect is not ideal, while the combined buffer tank has obvious depressurization effect and good stability. At the same time, the optimal structural parameters of the combined buffer tank are cut-in angle of 72, plane angle of 60 and depth of 1.65 mm. The excellent structure and parameters of the combined buffer groove are obtained, so that the pressure buffer of the regulating valve at the key position of the valve port achieves the best effect, and an effective solution is provided for solving the sticking problem of the valve core of the regulating valve when working.