| This paper in the coiling machine lap gradually pressurization system on the basis of analysis and research, design a new type of electrohydraulic proportional control technology based on the coiling machine lap gradually pressurization mechanism, and gives the corresponding control circuit and control algorithm and the two different control mode from the open loop and closed loop two aspects respectively made full research, and from the Angle of theory and experiment of the control system is carried out the analysis and argumentation. This paper carry on the main work and obtain the main conclusion shown below:(1) Mechanical and pneumatic coiling machine lap gradually pressurization mechanism was analyzed on the current. Through the analysis the points:1) Mechanical gradually pressurization mechanism work stability, but the pressure regulating characteristic difference, the control precision is low, with increasing the diameter of the lap, the pressure gradually diminish.2) Pneumatic coiling machine lap gradually pressurization mechanism adopted mechanical pressure valve and gradually supercharging valve, and at the same time also need configuration corresponding air compressor, through to the valve port open degree control make lap pressure under control, but gas compressibility is very big, in the process of work pressure and unstable, it makes lap coiling quality is difficult to be assured, and at the same time, production and manufacturing corresponding valve need cost is also very high.(2) From the point of view of mechanics to gradually pressurization mechanism were analyzed, introduced a lap of the pressure formula. With the aid of matlab software draw out lap coil in the process of the pressure change curve, quantitative given as lap thickness change gradually pressurization mechanism should be applied corresponding pressure. Finally, the comprehensive analysis and comparison to the electrohydraulic proportional technology and the advantages and disadvantages of electro-hydraulic servo technology, the comprehensive consideration after a set of design based on the electro-hydraulic proportional control technology of coiling machine lap gradually pressurization mechanism. (3) The influence of established gradually supercharging system mathematical model, the paper theoretically analyzes the overflow valve, hydraulic cylinder and selection on the system stability;Using Matlab software Simulink toolbox to the mathematical model of the simulation analysis, through the research time domain response characteristic and the frequency domain response characteristics on system stability judgment. Combined with theory analysis, simulation and parameter query, can reach the following conclusion:1) Gradually supercharging system hydraulic loop response characteristics can approximate for second order system, the system and the stable time of the damping ratio with ζ changes, when hydraulic cylinder damping ratio ζ=1.5system can in the shortest possible time to achieve stability.2) Theoretically can see:This design gradually supercharging system rise time is0.026S, peak time was0.046S, stable time was0.26S, maximum overshoot is25%. From the simulation data can show that the system has faster response speed and better stability.(4) To PID control algorithm and the control principle was analyzed, and choose the incremental PID algorithm as the system control algorithm. By empirical try rounding fixed method after repeatedly testing that it is concluded that the optimal PID control parameters. That experiments show:In the Kp=2.6, TI=7.3, TD=8.2system can in the shortest possible time to achieve stable state.(5)From the point of view of experiment to the system are analyzed and demonstrated. The experiment platform are analyzed, from theory analysis and computation are given the expected value, through the open loop control experiment of a discrete take20sets of data to carry on the analysis, through the observation and record the experiment data, the experiments were sampling record the six groups of experimental data, the six sets of data analysis and choose the most close to the theory of data for the laboratory of measured data in sampling record20sets of data, the real value and theoretical value between the largest absolute error is only0.08MPa, maximum relative error is only4.02%, the actual measured coil machine lap gradually supercharging pressure and displacement curve and theory of pressure and displacement curve are basically the same.Then the process of closed loop with Labview software with the corresponding data acquisition card collection experimental data, the experimental results are analyzed finally. From the experimental data can see:In some sampling18sets of data, the real value and theoretical value between the largest absolute error is only0.04MPa, maximum relative error is only2.12%, and for real measured coil machine lap gradually supercharging pressure and displacement curve and theory of pressure and displacement curve phase approximation. In this experimental system, the line along the path of the pressure loss and partial pressure loss and system of flow loss, all these factors will lead to the hydraulic system of the actual output pressure value smaller than the theoretical value, it is mainly that because the actual measurement has certain interference exists, the general trend with the theoretical basic approximation. The results show that the third chapter the established system mathematical model is correct, that based on the electro-hydraulic proportional control coiling machine lap gradually pressurization system has high control precision, small in volume, pressure stable advantages.Through the analysis and experiment shows that based on the electro-hydraulic proportional control coiling machine lap gradually pressurization mechanism can satisfy the keep lap under pressure constant requirements. This topic results to textile industry automation level improved, but also to optimize product quality, reduce production cost has important significance. On the other hand, the electro-hydraulic proportional control coiling machine lap gradually supercharging system is a collection of mechanical, electronic, hydraulic technology in the integration of automation control system, have certain academic research value, can be used as our country textile machinery technical reserves. |
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