Velocity Summing Linear Actuator Redundancy
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Solution Overview
Problem
Existing linear actuation systems face challenges in maintaining functionality after component failure, particularly due to issues with motor redundancy and unwanted electrical power generation, as well as performance reduction from anti-rotation features.
Innovation Solution
A dual-channel redundant linear actuation system with primary and secondary channels, each equipped with motors, brakes, and a velocity summing gearbox, where the sleeves are capable of rotation and connected through a gear housing to allow seamless transition of motion between channels, ensuring continuous operation even with motor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundant linear actuation system with multiple motors is used to maintain functionality after component failure, then reliability is improved, but unwanted electrical power generation occurs and device complexity increases
Solution Approach 1:
The patent extracts and removes the harmful function of unwanted electrical power generation from the redundant motor system. When one motor fails, the system actively disengages or brakes the failed motor to prevent it from generating unwanted electrical power, while maintaining the redundant motor's ability to provide motion. This separates the useful function (motion provision) from the harmful function (unwanted power generation).
Solution Approach 2:
The patent converts the potential harmful effect of a failed motor acting as a generator into a beneficial controlled state. By implementing active braking or disengagement mechanisms, the system prevents the failed motor from generating unwanted electrical power, and in some configurations, the failed motor's inertia can be utilized to maintain system momentum or reduce the load on the remaining functional motor.
2Reliability
If anti-rotation features are added to prevent unwanted motion, then reliability is improved, but performance is reduced due to friction and mechanical constraints
Solution Approach 1:
The patent replaces static anti-rotation features with dynamic control mechanisms. Instead of using fixed mechanical constraints that continuously resist motion, the system employs active braking and controlled engagement mechanisms that only apply constraints when needed (e.g., when preventing reverse motion or when a motor fails). This dynamic approach maintains reliability while minimizing friction and mechanical resistance during normal operation.
Solution Approach 2:
The patent changes the state of the anti-rotation features from always-engaged to conditionally-engaged. By monitoring system state and motor performance, the control system adjusts the engagement level of braking and anti-rotation mechanisms, allowing them to provide necessary constraints only when required, thereby maintaining performance during normal operation while ensuring reliability when needed.
3Reliability
If velocity summing gearbox is used to combine motor outputs, then continuous operation is enabled after failure, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the velocity summing function into separate, modular components rather than requiring a single complex integrated gearbox. Each motor has its own dedicated gearbox unit, and the outputs are combined through a simpler coupling mechanism. This segmentation allows for easier manufacturing, maintenance, and replacement of individual components while maintaining the velocity summing capability for continuous operation after failure.
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 continuous operation of the linear actuator with failed motors by adjusting motor speeds and using gearing to maintain linear motion without performance reduction, ensuring reliability and precision in applications requiring constant actuation.
Implementation Method 1
a rotary motion is then converted into linear motion via the use of a screw assembly. Various technologies exist for the screw assembly including Acme or lead screws, ball screws, and roller screws.
Data Source
AI summary
A linear actuation system has two linear actuator channels acting in tandem and a gear housing connecting the two actuator channels and providing an output for the actuation system. The gear housing has multiples gears with at least one gear connected to each actuator and is movable.