Rocket Engine Pressure Control via Model-Based Mixing Ratio Estimation
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Solution Overview
Problem
Rocket engine control systems face challenges in accurately controlling pressure and mixing ratio without measuring the mixing ratio, especially in non-linear systems, where traditional methods are uncertain and require complex measurements or redundant sensors.
Innovation Solution
A method using a pressure feedback loop to deliver control signals to control valves, estimating the mixing ratio from control valve signals and measured pressure, and employing a model that can account for non-linear systems, potentially using an artificial neural network for accurate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional open loop control is used to control rocket engine pressure and mixing ratio, then the control system is simple, but the control accuracy and reliability are low due to high uncertainty
Solution Approach 1:
The patent implements a closed-loop feedback control system where the measured pressure is fed back to the regulator, which adjusts the control valves accordingly. This feedback mechanism eliminates the high uncertainty of open-loop control by continuously monitoring and correcting the actual pressure and mixing ratio based on the model-based estimates and measured values.
2Reliability
If closed loop regulation is implemented to improve control accuracy, then measurement modules are required, but the device complexity and cost increase due to additional sensors and redundant measurements
Solution Approach 1:
The patent introduces a mathematical model as an intermediary that estimates the mixing ratio based on measured pressure and control valve positions. This model acts as a virtual sensor, providing the necessary measurement information without requiring physical mixing ratio sensors, thereby reducing device complexity while maintaining control accuracy.
Solution Approach 2:
The patent replaces physical measurement devices (mixing ratio sensors) with a computational approach using a mathematical model. This substitution eliminates the need for complex hardware measurement modules while achieving the same control objective through software-based estimation.
3Ease of operation
If linear compensation methods are used to maintain mixing ratio, then the control is simple, but the accuracy is limited because linear compensation is only applicable in the vicinity of a chosen operating point and cannot handle non-linear systems
Solution Approach 1:
The patent employs a dynamic, adaptive model that can handle non-linear system behavior across varying operating conditions. Unlike static linear compensation, this model dynamically adjusts its predictions based on the current operating point, maintaining high accuracy throughout the entire operating range of the rocket engine.
Data Source
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AI summary
The invention relates to a method and device for controlling the pressure (PGC) and a mixture ratio of a rocket engine on the basis of a set pressure value (PGCc) and set mixture ratio value (RMc). In said method and device, a control generates signals for controlling two control valves (VR1, VR2) of said engine, the control using a pressure feedback loop. Said control also uses a determination of an estimated mixture ratio value (RMe). The estimated mixture ratio value is obtained by a model generating estimated mixture ratio values from at least one of the two signals for controlling control valves and/or the measured pressure.