Lubricant-Flow Damping for Electromechanical Actuator Failures
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Solution Overview
Problem
Electromechanical actuators (EMAs) face uncontrolled movement and potential damage during power loss, as they lack sufficient damping to prevent overshooting and collision with end stops due to minimal friction resistance.
Innovation Solution
A damping arrangement using a lubricant fluid and constrained passages to create a damping force by restricting fluid flow, which slows down the actuator member during failure events, and includes pistons, biasing members, and a structural portion for load-bearing support, allowing for controlled deceleration and repeated use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lubricant fluid is used to reduce friction on the actuator member, then movement efficiency is improved, but damping force during failure events is insufficient
Solution Approach 1:
The patent applies local quality by creating a constrained passage with specific geometry (narrower section) that concentrates the lubricant fluid flow restriction to a localized area. This localized flow restriction generates the necessary damping force only when needed during failure events, while maintaining efficient fluid flow during normal operation.
Solution Approach 2:
The patent changes the physical parameters of the lubricant fluid flow by restricting it through a constrained passage with specific dimensions (passage diameter and exit aperture diameter). By controlling the flow restriction parameters, the system achieves different flow characteristics during normal operation versus failure events, providing both efficiency and damping.
2Speed
If the actuator member moves rapidly during power loss, then the system responds quickly to failure, but damage to end stop and components occurs
Solution Approach 1:
The patent implements beforehand cushioning by pre-configuring the constrained passage within the end stop structure. When the actuator member moves rapidly during power loss, the lubricant fluid flow through the constrained passage automatically generates damping force that cushions the impact, preventing damage to the end stop and other components.
Solution Approach 2:
The patent converts the harmful rapid movement during failure into a beneficial damping effect. The kinetic energy of the rapidly moving actuator member forces lubricant fluid through the constrained passage, and the flow restriction converts this kinetic energy into damping force that protects the system from damage.
3Reliability
If a damping arrangement is added to prevent uncontrolled movement, then protection during failure is improved, but device complexity increases
Solution Approach 1:
The patent merges the damping arrangement with the existing end stop structure. The constrained passage is integrated into the end stop, and the lubricant fluid system is already present in the electromechanical actuator. This merging approach provides failure protection without adding separate complex damping systems.
Solution Approach 2:
The lubricant fluid system serves multiple functions: it provides lubrication during normal operation to reduce friction, and it provides damping force during failure events by flowing through the constrained passage. This multi-functionality eliminates the need for separate damping components.
4Reliability
If piston size and passage size are optimized for damping coefficient, then damping performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the parameters of the constrained passage (passage diameter and exit aperture diameter) and piston dimensions to achieve the desired damping coefficient. By carefully selecting these parameters, the system achieves effective damping while accounting for manufacturing tolerances in the additive manufacturing process.
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 damping arrangement effectively reduces the likelihood of damage by providing a controlled damping force, allowing the actuator member to come to rest safely and enabling multiple reuse cycles while integrating structural support and cost-effective design.
Implementation Method 1
a lubricant fluid for lubricating the actuator member during movement of the actuator member. The damping arrangement comprises a constrained passage, the constrained passage configured to restrict a flow of the lubricant fluid in order to provide a damping force to resist a movement of the actuator member during a failure event.
Data Source
AI summary
A damping arrangement for an electromechanical actuator including an actuator member and a lubricant fluid for lubricating the actuator member during movement of the actuator member. The damping arrangement comprises a constrained passage, the constrained passage configured to restrict a flow of the lubricant fluid in order to provide a damping force to resist a movement of the actuator member during a failure event.