Rocket Engine Actuator Control via Bang-Bang Inhibition
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Solution Overview
Problem
Current servocontrol systems for engine actuators, such as those in rocket engines, require costly high-bandwidth and high-electrical-power electronics for effective control, leading to unnecessary energy consumption and complex electronics due to the need for precise and rapid actuation.
Innovation Solution
Implementing slow actuators controlled in bang-bang mode with non-linear control strategies that include an inhibition module and duration quantization to generate commands, reducing the need for complex electronics and minimizing unnecessary oscillations near the operating point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-bandwidth and high-electrical-power electronics are used for servocontrol of actuators, then effective control with extremely short transient is achieved, but energy consumption increases and device complexity increases
Solution Approach 1:
The patent implements bang-bang control with periodic pulse commands instead of continuous high-bandwidth control signals. The actuator is activated in discrete on/off pulses only when the error exceeds the dead zone threshold, converting continuous high-power control into periodic low-power actuation while maintaining effective control performance
Solution Approach 2:
The patent extracts and eliminates the continuous high-power electronics control loop by replacing it with simple threshold-based bang-bang control. The complex servocontrol electronics are removed entirely, keeping only the essential actuation function while discarding the energy-intensive continuous control mechanism
2Measurement precision
If continuous servocontrol is implemented to maintain actuator position relative to setpoint, then precise control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive, complex continuous control electronics with simple, inexpensive threshold comparison and pulse generation logic. The control system uses basic dead zone detection and bang-bang pulse generation instead of sophisticated servocontrol circuits, achieving adequate precision at fraction of the cost and complexity
Solution Approach 2:
The patent segments the control range into distinct zones: a dead zone where no control action is taken, and outer zones where bang-bang control is applied. This segmentation allows the system to avoid complex continuous control in the critical mid-range while maintaining simplicity through discrete control regions
3Device complexity
If slow actuators are used instead of high-bandwidth actuators, then device complexity and energy consumption decrease, but control effectiveness with short transient response deteriorates
Solution Approach 1:
The patent applies preliminary action by accumulating error beyond the dead zone threshold before triggering actuator activation. This allows slow actuators to catch up with the accumulated error through sustained pulse application, compensating for their slower response while maintaining overall control effectiveness without requiring high-bandwidth components
Data Source
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AI summary
The device (105) has a subtractor (10) for calculating an error obtained from a difference between a measurement of a variable (PC) and a set point (PCc). A command generating unit (20) generates a bang-bang type command to be applied to an actuator (VR1) i.e. slow actuator, from the error. A sending unit (30) sends of the command to the actuator. An inhibitor (INH) is placed in an upstream of the command generating unit to inhibit the error when the error lies within in a given range (ZM). A quantifier (QD) quantifies a duration of the command. Independent claims are also included for the following: (1) an engine comprising an adjustment device (2) a method for adjusting an operating variable of an engine according to an set point (3) a computer program having a set of instructions for executing an engine operating variable adjusting method (4) a computer readable storage medium for storing a computer program to implement the engine operating variable adjusting method.