Logarithmic Pressure Compensation for Solid Rocket Thrust Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid propellant rocket motors face challenges in controlling thrust due to the difficulty in extinguishing the propellant once ignited and varying thrust levels, requiring complex control schemes and significant computing power to operate effectively over a wide range of conditions.
Innovation Solution
A control system that measures combustion chamber pressure, calculates error signals, filters them in the logarithm domain, and exponentiates the results to generate control signals for valve positioning, allowing for efficient thrust control with minimal computing power and a wide operational range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex control schemes are used to control thrust over a wide range of operating conditions, then the rocket can operate effectively under varying conditions, but the device complexity and computing power requirements increase significantly
Solution Approach 1:
The patent transforms the control problem from the physical domain to the logarithm domain by applying logarithmic transformation to pressure measurements and control signals. This parameter change linearizes the relationship between valve position and chamber pressure, enabling a simple proportional controller to achieve wide operating range coverage without complex control schemes. The logarithmic transformation converts multiplicative relationships into additive ones, simplifying the control law while maintaining adaptability across varying operating conditions.
2Measurement precision
If complex control schemes with multiple controllers are implemented to handle varying thrust levels, then thrust control accuracy is improved, but the computing power requirements and system complexity increase
Solution Approach 1:
The patent replaces complex computational control algorithms with a mathematically transformed control approach in the logarithm domain. By applying logarithmic transformation, the control system achieves accurate thrust control using simple proportional control logic instead of requiring multiple controllers and extensive computing power. The transformation converts the nonlinear control problem into a linear one that can be solved with minimal computational resources while maintaining precision.
3Measurement precision
If pressure compensation methods are implemented to account for unknown variables, then control accuracy is improved, but the computational complexity increases
Solution Approach 1:
The patent implements pressure compensation by working in the logarithm domain where unknown variables and disturbances have reduced impact on control accuracy. The logarithmic transformation naturally compensates for certain types of uncertainties and nonlinearities in the system, achieving accurate pressure control without requiring complex compensation algorithms. This parameter transformation approach simplifies the control system while maintaining or improving accuracy compared to traditional methods.
Data Source
AI summary
Rockets, rocket motors, methods of controlling a rocket and methods of evaluating a rocket design are disclosed. In some embodiments, a method of controlling a rocket may include measuring a combustion chamber pressure, calculating a logarithm of the measured combustion chamber pressure, and computing the difference between the logarithm of the measured combustion chamber pressure and the logarithm of a reference combustion chamber pressure value to generate an error signal. The method may further include filtering the error signal to generate a compensated signal in the logarithm domain, and exponentiating of the compensated signal in the logarithm domain to provide a compensated signal in the physical domain.