Redundant Rocket Engine Servo Control for Fault-Tolerant Thrust Regulation
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Solution Overview
Problem
Conventional electromechanical servo systems for liquid rocket engines face challenges in achieving high reliability, accuracy, and fast response while maintaining a small size and light weight, due to large and heavy multi-redundancy actuators and low inherent reliability of servo drivers.
Innovation Solution
A multi-redundancy electromechanical servo system with triple-redundancy control and double-redundancy driving, featuring a servo controller with independent control modules and redundancy management, permanent magnet synchronous motors, and double-winding actuators to ensure reliable operation even with faults, simplifying the engine's gas-liquid system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-redundancy electromechanical actuators are used to ensure high reliability, then the reliability of the servo system is improved, but the size and weight of the system increase
Solution Approach 1:
The servo driver is segmented into multiple independent driving modules (first driving module, second driving module, third driving module). Each module can independently drive the actuator, allowing the system to maintain functionality even when some modules fail. This segmentation enables redundancy without requiring a complete duplicate of the entire actuator system, thereby reducing overall weight while maintaining reliability.
Solution Approach 2:
The patent applies redundancy locally at the driving module level rather than system-wide. Each driving module is designed with specific functional capabilities, and the electromechanical actuator incorporates multiple winding sets (first winding set, second winding set, third winding set) that can be selectively activated. This localized redundancy approach minimizes the additional weight compared to full system redundancy.
2Reliability
If multi-redundancy electromechanical actuators are used to ensure high reliability, then the reliability of the servo system is improved, but the volume of the system increases
Solution Approach 1:
Multiple winding sets (first winding set, second winding set, third winding set) are merged into a single electromechanical actuator structure. These windings are electrically independent but share the same magnetic circuit and mechanical components. This merging approach provides redundancy while avoiding the need for separate actuator housings and mechanical structures, thereby minimizing volume increase.
Solution Approach 2:
The electromechanical actuator is designed with multi-functionality, where a single actuator structure can be driven by multiple independent driving modules through different winding sets. This universal design allows the same physical actuator to serve multiple redundant functions, eliminating the need for separate actuator volumes for each redundant channel.
3Device complexity
If conventional electromechanical servo systems are used, then the system structure is simplified compared to electro-hydraulic systems, but the inherent reliability of servo drivers remains low
Solution Approach 1:
The patent implements beforehand cushioning by designing the servo driver with multiple independent driving modules and redundant winding sets before any failure can occur. The system includes fault detection and isolation capabilities that prepare redundant pathways in advance. When a fault is detected in one driving module or winding set, the system can immediately switch to another module without interruption, cushioning against the impact of failures and maintaining high reliability.
4Reliability
If redundancy is increased to achieve high reliability, then the ability to operate with failures is improved, but the device complexity increases
Solution Approach 1:
The servo driver incorporates feedback mechanisms that continuously monitor the operational status of each driving module and winding set. Fault detection circuits provide real-time information about system health, enabling the control system to identify failures and switch to redundant components. This feedback approach manages complexity by providing intelligent control logic that automatically handles redundancy management, reducing the need for complex manual intervention or overly complicated hardware architectures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves high reliability, accuracy, and fast response for thrust and mixture ratio regulation, with the ability to operate with two control failures and one drive failure, while reducing size and weight, and simplifying the engine's energy supply and control mechanisms.
Implementation Method 1
permanent magnet synchronous motors
Data Source
AI summary
A multi-redundancy electromechanical servo system for regulating a liquid rocket engine, comprising a triple-redundancy servo controller (1), a double-redundancy servo driver (2), double-winding electromechanical actuators (4, 5), a triple-redundancy position sensor (6), a thrust regulator (8) and a mixed ratio regulator (9). Engine thrust, a mixed ratio regulation instruction and a feedback signal of the triple-redundancy position sensor are inputted to the triple-redundancy servo controller, and the triple-redundancy servo controller outputs thrust and mixed ratio regulation PWM wave control signals to the double-redundancy servo driver. The double-redundancy servo driver outputs a three-phase variable-frequency variable-amplitude sine wave current to drive the double-winding electromechanical actuators to drive the thrust regulator and the mixed ratio regulator to move, thus achieving engine thrust and mixed ratio regulation. The present servo system has a simple system and excellent control characteristics, has the ability to “control a two-degree fault operation and drive a one-degree fault operation”, and significantly improves the reliability and usage maintainability of the thrust and mixed ratio regulation of the liquid rocket engine. Also disclosed is a method for implementing the foregoing multi-redundancy electromechanical servo system.