| Semi-flexible pavement material is a new type of pavement material composed of aggregate,water,cement,emulsified asphalt and fiber,which requires special construction equipment for pavement construction.The equipment integrates the batching hydraulic system and the continuous stirring device,and can realize the metering and mixing of semi-flexible pavement materials under normal temperature conditions.Among them,the metering essence of the batching hydraulic system is the coordinated control of multi-valve-controlled motors,and the optimal premise of the coordinated control of multi-valve-controlled motors is that the single-valve-controlled motor itself can accurately measure;the continuous stirring device mixes the accurately metered materials evenly.However,due to the influence of the environment and its own factors,the batching hydraulic system often has problems such as vibration,poor anti-interference and low cooperative coupling,and the mixing uniformity is often affected by the mismatch of operating parameters,resulting in poor construction road quality.Therefore,in order to improve the construction quality of semi-flexible pavement,this paper conducts research on the metering optimization strategy of the batching hydraulic system and the mixing characteristics of the continuous stirring device.Firstly,aiming at the problem of low metering accuracy and poor stability of single-valve-controlled motor,this paper designed an improved particle swarm optimization(IPSO)optimized hybrid PID(PID-fuzzy PID)control method.On the basis of traditional PID,this method introduced IPSO to optimize PID parameters,and added fuzzy control(Fuzzy)to enhance the robustness of the control system.The results show that compared with the response performance of IPSO-PID control and IPSO-FPID control,the time of IPSO optimized hybrid PID control entering the steady-state stage is shorten by 2.29 s and 0.11 s respectively,and it has the advantages of no overshoot of IPSO-PID control and small cycle fluctuation of IPSO-FPID control.Secondly,aiming at the problem that the tracking performance and cooperative performance of multi-valve-controlled motor are difficult to balance,and the compensation of traditional deviation coupling control is poor,this paper designed a mean deviation composite control strategy.Based on the traditional deviation coupled cooperative controller,this method introduced the IPSO optimal hybrid PID control method to build a composite controller for bias coupling,and improved the cooperative controller.The results show that the mean deviation composite control strategy can reduce the tracking error and collaborative error of the batching hydraulic system and improve the metering accuracy.Finally,in order to study the influence of the particle motion characteristics and operating parameters in the continuous stirring device on the mixing uniformity,the discrete element method was used to simulate the particle motion state in the continuous stirring device;by counting the mass of particles in the multi-grid under different operating parameters,the uniformity of the mixing process and the mixing outlet were analyzed.The results show that the speed of the particles in the middle area along the stirring axis is smaller than that on both sides,and the particle flow is in a spiral motion along the stirring shaft;taking the dispersion coefficient as an index,the uniformity of the particles from the inlet to the outlet increases continuously;and analyze the dispersion coefficient of the stirring outlet by the variance method,determine that the particle supply is the most influential factor,and the optimal operation parameter combination is the particle supply of 164t/h and the stirring shaft speed of 130r/min.The research on the batching hydraulic system and continuous stirring device of semi-flexible pavement construction equipment can be extended to the field of multi-material metering and mixing,which provides a certain reference for improving metering accuracy and mixing uniformity. |
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