| Electro hydraulic servo pump control system is a volume servo control unit which is highly integrated with a servo motor,a quantitative pump,a hydraulic cylinder and functional valves.By adjusting the speed and torque of the servo motor,the system pressure and flow are changed to control the hydraulic cylinder actuation output.Compared with the traditional valve control system,the system eliminates the huge hydraulic station,complex pipeline system and expensive servo valves,which effectively overcomes the inherent technical defects of electro-hydraulic servo valve control technology,such as poor anti-pollution ability,low integration,serious energy waste.Electro hydraulic servo pump control system has technical advantages such as high efficiency and energy saving,high power to weight ratio and environmental friendliness.The above technical advantages provide strong support for the application of electro hydraulic servo pump control system,but the volume direct drive control scheme with servo motor-quantitative pump-hydraulic cylinder brings many challenges to the efficient operation of the system.Electro hydraulic servo pump control system still faces many problems that need to be solved urgently in the stage of technology promotion.First of all,due to the large inertia of the servo motor and the quantitative pump and the time delay of the volume servo response,the static accuracy of the system is not high and the dynamic performance is limited.The response speed,bandwidth and positioning accuracy of the system usually lag behind the traditional valve control system.In addition,electro hydraulic servo pump control system greatly reduces the heat dissipation capacity while pursuing the high power-to-weight ratio and high integration,resulting in heat becoming an urgent problem to be solved before the system is installed and applied.To sum up,the problems of low control performance and serious heat generation in electro hydraulic servo pump control system directly affect the improvement of the working quality of the system,and restrict the promotion and engineering application of this technology.This paper takes the improvement of the working performance for electro hydraulic servo pump control system as the research goal.Research is carried out around the system high-performance control and heat power characteristic optimization.Based on the study of electromechanical-hydraulic coupling nonlinearity of electro hydraulic servo pump control system,the control mechanism of current loop,speed loop,position loop and pressure loop in the system is revealed,and a high-performance control strategy for system position/force is proposed.The heat power model of each key component is established,the heat power characteristics of each key component and the system are analyzed,and a multi-objective optimization and coordination matching strategy for component parameters is proposed,taking into account the dynamic characteristics,and realizing the optimization of the heat power characteristics for the system.The specific research contents include the following aspects:(1)The basic composition and working principle of electro hydraulic servo pump control system are analyzed,and the relevant mathematical models are established by using the mechanism modeling method.The system-level design is carried out around the requirements of various indicators,the load matching method is proposed,and the main dynamic parameters of the system are determined.Research on the inertia matching of servo motor and quantitative pump is carried out,and the selection requirements of the core component electrohydrostatic pump unit are put forward.(2)The system electromechanical-hydraulic coupling dynamics model is established,and the system electromechanical-hydraulic coupling law is revealed from the perspective of energy flow.The electromechanical-hydraulic coupling characteristics of the hydraulic cylinder and the load,the pressure-flow coupling characteristics of the hydraulic transmission system,and the electromechanical coupling of the electrohydrostatic pump unit are analyzed.The mechanism of multi-parameter action of the system under electromechanical-hydraulic coupling conditions is revealed.The traceability analysis of the nonlinear nature of the system is carried out,and the nonlinear mapping model of the electrohydrostatic pump unit flow is established.The nonlinear behavior of the system flow under the excitation of rotational speed and pressure is studied by partition.(3)The control mechanism of the current loop,speed loop,position loop and force loop of electro hydraulic servo pump control system is revealed,and the dynamic frequency response characteristics of each control link are analyzed.The nonlinear mapping adaptive backstep control strategy is proposed,and the rotational speed of electrohydrostatic pump unit is obtained by using the nonlinear model inverse solution,which realizes the high-performance control of the system position.The load torque dynamic compensation active disturbance rejection control strategy is proposed.The reference balance torque control is realized through the active disturbance rejection control algorithm,and the dynamic compensation is carried out based on the "excess flow",and the high performance control of the system force is realized.(4)The energy transfer and conversion models of electro hydraulic servo pump control system are established,and the traceability analysis is carried out on the nature of the heat power in the system.The heat power model of each key component is established.The heat power characteristics of each key component and the system are analyzed,and the efficiency characteristics are studied.The optimization index of heat power characteristics is refined,and the multi-objective optimization and coordination of component parameters are carried out,taking into account the dynamic characteristics,and realizing the optimization of the heat power characteristics for the system.(5)Electro hydraulic servo pump control system is applied to industrial equipment such as gas turbine guide vane adjustment,lithium battery pole piece rolling and steam turbine oil motor control.The relevant theories such as electromechanical-hydraulic coupling characteristics,high-performance control,and heat power characteristic optimization are experimentally verified through engineering applications,and the feasibility and effectiveness of the proposed theoretical method are further demonstrated.This research will lay a theoretical and technical foundation for the engineering popularization and application of electro-hydraulic servo pump control technology and the leap-forward development of the system towards compactness,high efficiency and intelligence. |
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