低温贮箱多路管道增压的一种模糊算法研究

火箭发动机地面试验中，低温推进剂贮箱增压过程的传热、传质以及湍流流动过程十分复杂。贮箱增压系统具有非线性、时间滞后、参数变化不确定等特点，对增压系统难以建立精确的数学模型。因此，以低温推进剂贮箱内压力稳定为目的，提出了采用多路、不同直径管道增压的模糊控制方案；应用模糊控制算法中的最大隶属度法进行解模糊化，制定增压管路的模糊控制表，建立了以压力为控制变量的模糊控制器。分别对预增压过程和保持增压过程的两种工况进行了仿真。仿真结果表明：模糊控制算法能有效提高推进剂贮箱中压力调节的控制精度和响应速度，使得离开贮箱的推进剂压力稳定地满足发动机泵入口的压力和净吸程要求。

Research on fuzzy control algorithm of cryogenic propellant-tank pressurization

In the rocket engine ground experiments, the cryogenic propellant tank ressurizat-ion is associated with complex heat transfer, mass transfer and turbulent flow. Characterized by the nonlinear and real-time system with considerable uncertainty, the accurate mathematic model of the control system of tank pressurization is quite difficult to be established. Based on steady pressure in the tank, the pressure in the air cushion is set as the control target parameter in the system of tank pressurization with multi-pipes of different sizes. Using the algorithm of maximum degree of membership, the fuzzy control table of multi-pipes pressurization is set up; the fuzzy controller of pressure parameter is built. Furthermore, two work condition of prep-pressurization and retain pressurization were simulated, the new fuzzy control system of tank pressurization can improve the control precision and the response speed significantly, and therefore, satisfy the strict demands on the pressure and net suction head in the entrance of the rocket engine.