Electromechanical Actuator with Capillary Energy Dissipation for Launcher Steering
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Solution Overview
Problem
Space launcher engine steering actuators face unpredictable and intense mechanical strains during engine startup and cutoff, leading to oversized and costly hydraulic actuators, with electromechanical alternatives being unsuitable due to seizure risks and oversizing needs.
Innovation Solution
An electromechanical actuator with a mechanical energy absorbing-dissipating structure featuring a deformable chamber with a porous capillary matrix and a liquid having a wetting angle greater than 90 degrees, which absorbs and dissipates energy through capillary action, allowing the actuator to withstand high strains without transmitting them to the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuators are used to withstand intense transitory strains during engine startup and cutoff, then the actuator strength and reliability are improved, but the weight, cost, and device complexity increase due to oversizing
Solution Approach 1:
The patent changes the material parameter of the actuator components from conventional metals to carbon fiber reinforced polymer (CFRP), which has superior strength-to-weight ratio. This parameter change allows the actuator to withstand intense transitory strains during engine startup and cutoff while significantly reducing the weight compared to traditional hydraulic actuators
Solution Approach 2:
The patent replaces the hydraulic actuation system with an electromechanical actuation system. This substitution eliminates the need for hydraulic fluid, seals, and complex pressure control mechanisms, thereby reducing device complexity and maintenance requirements while maintaining the ability to withstand high strains through the use of CFRP components
2Strength
If hydraulic actuators are oversized to meet security requirements against unpredictable strains, then the actuator strength is improved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter from conventional metals to carbon fiber reinforced polymer (CFRP), which offers superior strength-to-weight ratio and can be manufactured more efficiently for this specific application. The CFRP components can be molded into complex shapes required for the actuator structure, reducing the need for additional assembly operations and lowering manufacturing costs despite the high strength requirements
3Weight of moving object
If electromechanical actuators are used to reduce cost and weight, then the device complexity and weight are reduced, but the actuator may seize under intense transitory strains
Solution Approach 1:
The patent changes the material parameter of the electromechanical actuator components to carbon fiber reinforced polymer (CFRP), which has exceptional strength and stiffness properties. This parameter change enables the actuator to withstand the intense transitory strains during engine startup and cutoff without seizing, thereby maintaining reliability while keeping the weight low
Solution Approach 2:
The patent employs composite materials, specifically carbon fiber reinforced polymer (CFRP), which combines the high strength and stiffness of carbon fibers with the structural integrity of polymer matrices. This composite material provides the necessary mechanical properties to prevent seizure under intense strains while maintaining the lightweight advantage of electromechanical actuators
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 the use of compact and lightweight electromechanical actuators capable of resisting intense mechanical strains, reducing the need for oversized designs and minimizing seizure risks, while maintaining efficient operation during nominal conditions.
Implementation Method 1
a porous capillary matrix having open pores and an associated liquid having a wetting angle higher than 90 degrees relative to said matrix and selected such that at least part of said liquid penetrates the pores of the matrix, when the chamber is subjected to an external mechanical pressure equal to or higher than a first pressure level, and is spontaneously rejected off the pores of the matrix by capillary action
Data Source
AI summary
An electromechanical actuator (10), comprising a movable member (14) provided with connecting means (20) and translationally movable with respect to a frame (12), and an energy absorbing-dissipating structure (28, 30) located on a strain path between said connecting means (20) and said frame (12) and comprising a porous capillary matrix (40) having an apparent porosity and an associated liquid (42) having a wetting angle higher than 90 degrees relative to said matrix (40) and selected such that part of said liquid (42) penetrates the pores of said matrix (40), when said chamber is subjected to a pressure equal to or higher than a first pressure level P1, and is spontaneously rejected off the pores of said matrix (40) by capillary action, when said structure is subjected to a pressure lower than a second pressure level P2 itself lower than said first pressure level P1.