DC Motor Flow Valve Multistage Control
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Solution Overview
Problem
Existing flow rate control valves for liquid rocket engines, particularly those using pneumatic actuators, face challenges in precise thrust control and are cumbersome, lacking advanced technologies for precise propellant mass and thrust management, which is crucial for stable rocket propulsion and safe stage separation.
Innovation Solution
A multistage control method using a DC motor that sets suitable limit values based on angular speed components and drive voltage to control the motor's speed within specific ranges, preventing overshoot or undershoot, allowing precise flow rate control by rotating the motor at intended speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a pneumatic actuator is used for flow rate control, then the valve can be actuated, but the device weight increases due to peripheral control devices
Solution Approach 1:
The patent replaces the pneumatic actuator system with a DC motor-driven system. The DC motor directly drives the valve mechanism through a gear reduction mechanism, eliminating the need for pneumatic cylinders, pressure regulators, and associated peripheral control devices. This substitution of mechanical/pneumatic systems with an electric motor system reduces overall device weight while maintaining actuation capability.
2Device complexity
If simple speed control is applied to the DC motor, then the control system is simple, but overshoot or undershoot occurs preventing precise flow rate control
Solution Approach 1:
The patent segments the speed control process into multiple stages with different control strategies. During the acceleration phase, one control parameter set is used, and during the deceleration phase, a different parameter set is applied. This segmentation of the control process into distinct phases allows precise control without overshoot or undershoot while maintaining relatively simple system architecture.
Solution Approach 2:
The control system dynamically adjusts parameters based on the operational phase. The controller switches between different control parameter sets depending on whether the motor is accelerating or decelerating. This dynamic adaptation of control parameters enables precise flow rate control without the complexity of more advanced control algorithms.
3Productivity
If the DC motor is controlled to reach target speed quickly, then productivity is improved, but overshoot occurs reducing control precision
Solution Approach 1:
The patent implements periodic switching of control strategies based on the motor's operational state. The controller periodically transitions between acceleration-phase parameters and deceleration-phase parameters, switching control modes at appropriate intervals. This periodic action allows the system to achieve rapid response while preventing overshoot by applying the appropriate control parameters at each phase transition.
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
Enables rapid and precise control of flow rates without overshoot or undershoot, allowing for smooth thrust adjustments, simplifying the control mechanism, and eliminating the need for additional tuning procedures, while being adaptable to various target values and thrust levels.
Implementation Method 1
a flow rate control valve which is opened or closed when a direct current (DC) motor rotates
Data Source
AI summary
A multistage control method of a flow rate control valve which is opened or closed when a DC motor rotates. The method includes dividing angular speed limit areas of the DC motor depending on stages based on limit values so that angular speed values of the DC motor are to be scheduled depending on the stages and controlling the DC motor to rotate at a determined angular speed value depending on a corresponding angular speed instruction to the DC motor within one angular speed limit area. When the angular speed value of the DC motor is outside a limit value of the corresponding angular speed limit area, the DC motor rotates at a determined angular speed value until reaching outside a limit value of the corresponding limit area depending on a corresponding angular speed instruction to the DC motor within an angular speed limit area of the next stage.