跟踪微分器在变流量燃气发生器上的应用研究

Research on Tracking Differentiator for VariableFlow Gas Generator

关键词:  变流量固冲发动机  燃气发生器  跟踪微分器  安排过渡过程  闭环控制  流量负调

Key words:  Variable flow ducted rocket  Gas generator  Tracking differentiator  Arrange transient process  Close-loop control  Flow anti-regulation

摘要:

变流量固冲发动机(VFDR)工作时，常采用PID控制器控制燃气发生器内燃气压强。对于阶跃或方波形式的压力指令，往往由于误差信号的突变使执行机构瞬时输出的控制力过大，产生较大的燃气压强超调与燃气流量负调，严重影响了控制系统的性能。为解决上述问题，在常规的PID控制器基础上，引入跟踪微分器(TD)给压力指令信号合理地安排一个快速无超调的过渡过程并提取微分信号。然后令燃气压强跟踪这个安排的过渡过程，使压强达到期望值。通过对变流量燃气发生器的非线性模型进行仿真试验，结果表明:相比于PID控制器，无论压力指令在高或低压强范围内，所提出的控制器均具有更高的稳态精度和快速性，压强的超调量不超过3.7%，响应时间在1s以内。此外，该控制器在抑制燃气流量的负调量上展现了巨大的优势，可将最大负调量减小2.7～3.25倍，显著地提升了VFDR的性能。

Abstract:

PID controller is often used to control gas pressure of gas generator when variable flow ducted rocket (VFDR) works. The pressure instruction in the form of step or square wave often makes instantaneous output control force of actuator too large due to the mutation of error signal， and produce larger overshoot of gas pressure and anti-regulation of gas flow， which seriously affect the performance of control system. In order to solve this problem， the tracking differentiator (TD) was introduced to arrange a rapid and no-overshoot transient process to pressure instruction signal and extracted differential signal based on conventional PID controller. Then gas pressure was traced to the transient process so that the pressure reached expected value. The nonlinear model of a variable flow gas generator was simulated. Simulation results show: compared with PID controller， this controller has higher steady-state accuracy and speediness in both high and low pressure range and the overshoot of pressure is below 3.7%， the response time is within 1s. In addition， this controller shows great advantage in reducing anti-regulation of gas flow. It can reduce anti-regulation about 2.7～3.25 times and significantly improves the performance of VFDR. So it has an important engineering application prospect.