截割机构延迟特性对巷道断面成型精度影响分析

Effect of delay characteristics of cutting mechanism on forming accuracy of roadway section

由于执行元件响应时间差、负载干扰以及液压油液的压缩性等多因素的干扰,使得手动换向阀或电磁换向阀控制掘进机截割煤岩时存在较大延迟,断面成型精度较低。考虑截割部执行机构延迟特性对截割误差的影响,根据掘支锚机组截割部系统硬件组成和基本参数,使用D-H方法建立了截割机构的运动学模型。分析了机构动作延迟对截割控制方程的影响,建立了横摆和纵摆截割动作延时情况下的截割头中心在巷道断面坐标系上的运动误差模型。通过MATLAB数值计算软件进行截割控制误差的仿真研究,研究结果表明:本文仿真工况下,在横摆速度恒定的情况下,当延迟时间分别为50,100和200 ms时,横摆截割的截割轨迹误差分别为10,20,40 mm。当横摆速度分别为50,100和200 mm/s时,横摆截割的截割轨迹误差分别为5,10,20 mm。随着截割部横摆速度和动作延迟的增大,截割轨迹误差随之增大。由于普通的开关电磁换向阀不易于进行流量实时调控,因此无法做到对截割部横摆速度的缓冲控制。需要充分掌握截割执行机构的延迟特性,在控制系统中做好提前量,消除动作延迟带来的截割误差。通过课题组自行研制的掘支锚机组实验平台进行实验研究,研究结果表明,本实验台截割部执行机构存在53 ms的延迟,通过对控制系统进行提前量控制,即截割部位移传感器在到达指定位移之前的53 ms乘以横摆速度后的位置下达停止指令,可削减动作延迟带来的截割误差。

Due to the interference of multiple factors,such as the response time difference of actuator,load interference and the compressibility of hydraulic oil,the manual directional valve or electromagnetic direc-tional valve controls the roadheader machine to cut coal and rock with a relatively large delay and low precision of section forming.Considering the influence of the delay of the actuator of the cutting part on the cutting error,the kinematics model of the cutting part is established by d-h method according to the hardware composition and basic parameters of the cutting part.The influence of the motion delay of the cutting mechanism on the cutting control equation is analyzed,and the motion error model of the cutting head center in the coordinate system of the roadway section under the condition of the delay of the cutting action of the transverse pendulum and the longitudinal pendulum is established.The simulation study of cutting control error is carried out using MATLAB numerical calculation software.The results show that under the simulation condition,under the condition of constant transverse velocity,when the delay time is 50,100 and 200 ms,the cutting track error of transverse pendulum cutting is 10,20 and 40 mm,respectively.When the transverse pendulum velocity is 50 mm/s,100 mm/s and 200 mm/s,the cutting track error of the transverse pendulum cutting is 5 mm,10 mm and 20 mm,respectively.With the increase of the transverse velocity and the motion delay of the cutting part,the cutting trajectory error increases accordingly.Because the general solenoid directional valve is not easy to control the flow in real time,it is not possible to control the speed of the cutting part.It is necessary to fully understand the delay characteristics of the cutting actuator,provide a good lead in the control system,and eliminate the cutting error caused by the action delay.Through the experimental study using the self-developed experimental platform of driving and supporting anchor,the results show that the actuator of test bench cutting part has a 53 ms delay.Through a leading time control on the control system,namely at the position of 53 ms multiplied by the speed of horizontal pendulum before the cutting position displacement sensor reaching the designated displacement,the stop instruction is given,then the cutting error resulted in by action delay can be reduced.