改进遗传算法在燃气流量调节中的应用

Application of Improved Genetic Algorithm for Gas Flow Regulation

关键词:  固体火箭冲压发动机  燃气发生器  控制系统  流量调节  遗传算法  适应度函数

Key words:  Solid rocket ramjet engine  Gas generator  Control system  Flow regulation  Genetic algorithm  Fitness function

摘要:

为了改善固体火箭冲压发动机燃气流量控制系统的性能，对于整个控制过程中的响应时间、压强超调量、流量负调量等重要的设计参数进行先验的评估和考量，通过改进遗传算法来整定PID控制器的参数，并在此基础上实现燃气发生器内的压强控制和流量调节。首先，为了加速遗传算法的收敛进程，优化了选择算子。此外，改进了适应度函数的表达式，从而降低了燃气负调量和流量在调节过程中的振荡。仿真结果表明：对于阶跃形式的压力指令，相较原始的PID控制器，经过改进的遗传算法寻优所设计的控制系统能够在更短的响应时间内基本消除燃气压强的超调量，并减小燃气流量的负调量。对于方波形式的压力指令，经过改进遗传算法优化的PID控制器能够大幅降低燃气发生器长时间工作后引起的流量负调量，显著提升了燃气流量控制系统的性能。

Abstract:

In order to improve the performance of gas flow control system in the ducted rocket， it is necessary to evaluate and consider the important design parameters such as response time， pressure overshoot， and flow negative regulation during the entire control process. Therefore， the improved genetic algorithm was adopted to tune the parameters of the PID controller. On this basis， the pressure control and flow regulation in the gas generator were realized. First， the selection operator was optimized to speed up the convergence process of genetic algorithm. In addition， the expression of fitness function was modified to reduce flow negative regulation and suppress flow oscillation. The simulation results show that for the step pressure command， compared with the original PID controller， the control system based on the improved genetic algorithm can effectively eliminate the pressure overshoot and reduce the flow negative regulation in a shorter response time. For the square wave pressure command， the PID controller tuned by the improved genetic algorithm can dramatically reduce the flow negative regulation after a long working time in gas generator， which significantly improves the performance of the gas flow control system.