基于前馈-反馈复合控制的盾构土压平衡控制

摘要

In order to compensate the earth pressure disturbance in working chamber caused by thrust speed variation and improve the precision of earth pressure balance (EPB) control system,a new EPB control system was designed based on thrust speed feedforward and earth pressure feedback control.The mathematical model of earth pressure in working chamber was proposed.According to the relationship among thrust speed,screw conveyor speed and earth pressure described in the earth pressure model,the adjustment of screw conveyor speed can be generated by the feedforward control loop and the effect of thrust speed variations could be eliminated before the earth pressure in working chamber being influenced.Meanwhile,the earth pressure feedback control loop could further reduce the earth pressure error to improve the system stable precision.Experiment was carried out on the shield machine test rig and the calculating result was compared with the experimental value to verify the earth pressure model.The calculating results show that the response time of EPB control system is reduced from 2.5 s to 0.5 s and the maximum relative error is decreased from 6.52％ to 1.54％ under the effect of feedforward control.Therefore,the performance of the EPB control system in shield tunneling machine is greatly improved.%为使盾构土压平衡控制系统既有较高的土压力控制精度又能及时消除推进速度波动对土压力产生的干扰,在现有土压平衡控制系统基础上,提出基于推进速度前馈-密封舱压力反馈的土压平衡控制系统.建立密封舱土压力数学模型,根据模型描述的推进速度、螺旋输送机转速和密封舱土压力之间的关系,通过推进速度前馈环节得到螺旋输送机转速相应的改变量,在推进速度波动对密封舱压力造成干扰之前进行补偿.同时,系统中的土压力反馈环节可以进一步消除其他干扰因素造成的土压力控制误差,提高系统稳态精度.利用在盾构实验台上采集的实验数据进行对比分析计算,验证土压力产生机理模型的有效性.结果表明,在前馈-反馈土压平衡控制系统中推进速度改变后螺旋输送机马达转速的响应时间约为0.5 s,而在反馈系统中约为2.5 s,前馈-反馈系统土压力控制最大相对误差为1.54％,而反馈系统为6.52％,因此证明当推进速度波动时,采用前馈-反馈控制的土压平衡控制系统具有更好的性能.