In chapter 2 a math model of the hydraulic system with motor speed regulation is built , in which the author builds the model of the converter - electromotor with two different modes , the vvvf control and the advanced vector control . using matlab , these models is simulated and , after comparing the results of system step response with different system parameters , some useful conclusions is drawn . then , through relevant experiments data study and theory analysis analyze some characteristics of the hydraulic system with motor speed regulation 论文中第一章介绍了变频技术的国际发展状况,以及在液压系统中的应用,第二章里建立了详尽的变频液压系统数学模型,尤其是对变频器电机环节的模型,分别建立了变频器的变频变压控制方式和先进矢量控制方式两种模型,利用matlab的时域仿真功能,对模型进行了仿真,对比分析了系统不同参数情况下的系统阶跃响应情况,得到了一些有意义的结论,然后通过相应系统实验验证了仿真模型,并通过实验数据研究,结合理论分析,进一步说明了变频驱动液压系统的一些特性。
The paper makes a systematic study on frictional torque model for hydraulic system , after the analysis of the ultra ? low speed principle of closed - loop system , it can be concluded that the existence of the difference between static frictional and dynamic frictional torque , and the periodic saltation of the dynamic frictional torque , are the main reasons of the low speed stick - skip to the electrohydraulic position servo system 针对伺服马达的低速性能,进行了低速实验研究,并兼顾快速性能进行了阶跃响应和正弦响应实验研究,对实验结果进行了分析,得出了一些有价值的结论,提出下一阶段进行实验的建议。
The innovative ideas in this paper is to replace the linear fixed - gain pid controller for a nonlinear pid controller . based on the step response curves of conventional control system , we analyze the ideal variety of three gains in different times and construct the simulated curves of proportional , intergral and derivative gain . the controllers has considered all sorts of imperceptible factors affecting the servo performances in a lpmsm servo system , which include the parametric uncertainties brought by the changes of the mobile mass , the dynamitic performance of the system and the size of input . to solve the problem of so many unknown parameters , we use transmit arithmetic to find the parameters which are fit for the system . to keep the robust and stable performance 本文的创新之处在于,将传统的固定增益的pid控制器用非线性pid控制器来代替,并在此基础上,就一般控制系统的阶跃响应曲线,分析了在不同响应时间阶段pid的三个增益调节参数的理想变化情况,并根据这些理想变化,分别给出了比例、积分、微分增益参数的一种连续的非线性拟和函数。在分析双位置环时,仔细考虑了能使系统性能变坏的各种因素,如系统的动态性能及控制出入能量的大小等等。
It really provides convenience to evaluate and optimize the design result . 3 ) vibration analysis has been fulfilled by calling some math libraries and graphic libraries in matlab to plot graphics such as velocity - time , displacement - velocity , step response , impulse response , gain - frequency and phase - frequency . we can know the capabilities of the spring system from the graphics 3 、在matlab环境下调用相应的数学函数库和图形库对设计的弹簧进行分析,绘制弹簧加载后系统的速度-时间响应曲线、速度-位移响应曲线、阶跃响应曲线、脉冲响应曲线、增益-频率响应曲线和相角-频率响应曲线,根据曲线来分析系统的各项性能。
First , the step response of the steam temperature process is obtained by experimentation , and the transfer function of the controlled process is calculated out using the step response data of the process . then , the pid parameters of the control system are optimized using the obtained process transfer function . finally , simulations are carried out to show the performance of the optimization - before system and optimization - after system 首先通过现场试验获取过热汽温过程的阶跃响应曲线,再根据试验得到的过程阶跃响应数据求取相应过程的传递函数模型;然后,根据传递函数模型进行控制系统pid参数的优化整定;最后,对优化前后的控制系统性能进行了仿真研究。
Because there are some shortcomings on tuning the parameters of conventional pid controller , which include the difficulty to make sure the direction of tuning , the possibility to cause the crash of system and the requirement of the system ' s model parameters , a new self - tuning algorithm of pid based on wavelet is proposed in this paper , which is using some wavelet items to describe the state of system through studying the connection between the step response of system and the wavelet transform of the step response and simulating it by use of matlab 由于常规pid控制器参数调整中存在不少缺陷,如调整方向难以确定,容易引起系统崩溃,有些方法需要知道预先确定系统模型参数等。针对这些情况,本文通过研究小波变换的特点以及控制系统单位阶跃响应和响应的小波变换之间的关系,在应用hatlab软件进行了大量仿真研究的基础上,找到了表征系统状态的小波指标,提出了一种基于小波变换的pid参数自调整算法,为研究小波变换在控制领域的应用提供了新的思路。
This provides new clew for making the controller ' s parameters of pump - control - motor speed governing system with inverter certain . ( 4 ) the performance simulating in time domain and open loop step experiment of pump - motor speed governing system with inverter are made , and the rules of parameter change affecting response performance are obtained . the theoretic references are provided to improve the system ' s performance ( 4 )对主要参数对变频泵控马达调速系统的性能影响进行了时域仿真分析和开环阶跃响应实验研究,得到了参数变化对响应性能指标的影响规律,为提高大功率大惯性变频泵控马达调速系统的性能指标提供了参考理论依据。
At first , the dynamic mathematic model is created in the light of the known dimensions and structure . then base on the mathematic model , dynamic analysis of the system is studied by drawing the open - loop bode diagram closed - loop bode diagram and step response curve using the analysis and calculating function of matlab . the influence factor on frequency character steady and performance of the system is also analyzed 首先,根据已确定的尺寸参数和结构需要,计算并建立起系统的动态数学模型,然后在已知系统数学模型的基础上,利用matlab语言强大的分析计算功能,对系统进行动态分析,通过画出系统的开环bode图、闭环bode图及系统的阶跃响应曲线,分析了系统的频率特性、稳定性及系统性能的影响因素。
And classic pid control method and numerical pid control method have been introduced in the paper . the paper adopt stabilization border method to set the pid parameters and simulates the control system which is based on matlab / simulink . simulation results indicate that pid control ’ s simulation results have a good effect in low - frequency stage , but it is not perfect in mid - frequency and high - frequency stage 采用稳定边界法实现对pid参数的整定,并基于matlab / simulink对控制系统进行了仿真,仿真结果表明:低频段pid控制正弦跟踪曲线取得了良好的效果,而在中频和高频段时的跟踪效果不是很好, pid控制的阶跃响应超调量较大, pid控制三角波曲线的高频性能也不理想。
Through simulation and calculating the four models , the influence on proportion coefficient , integral time constant , derivative time constant and partial feedback coefficient for system performance is analyzed . the ideal reference value of every parameters and step respond curves are given . the simulation result may be used as reference for making analogue controller or digital controller 通过对这四种模型的仿真研究,分析了各模型中比例系数、积分时间常数,微分时间常数及局部反馈系数对系统性能的影响,并给出了各参数较为理想的参考值及阶跃响应曲线,仿真结果对制作模拟控制器及数字控制器有一定的借鉴作用。