Dual-Input Planetary Linear Actuator With Motor Redundancy
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Solution Overview
Problem
Linear actuators have failure-prone components that can lead to system failure, and existing technologies face challenges in increasing their reliability.
Innovation Solution
A dual rotary input linear actuator design featuring a planetary gear system with two motors and a braking mechanism that allows either motor to be used as a sole input, providing redundancy and alternating usage to even out wear, while a fault detection system engages brakes in case of power loss or failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single motor is used to drive the planetary gear system, then the device complexity is reduced, but the reliability deteriorates due to failure-prone components
Solution Approach 1:
The single motor is segmented into two separate motors (first motor and second motor), each capable of independently driving the planetary gear system. This segmentation provides redundancy so that if one motor fails, the other can continue operation, thereby improving reliability while maintaining manageable system complexity through modular architecture
Solution Approach 2:
The system incorporates a brake mechanism that can be applied to either motor beforehand as a protective measure. This prior cushioning ensures that if one motor fails or experiences power loss, the brake prevents uncontrolled motion and allows the remaining motor to continue operation safely, improving reliability without significantly increasing complexity
2Reliability
If dual motors are used to drive the planetary gear system, then the reliability is improved through redundancy, but the device complexity increases
Solution Approach 1:
Both motors are designed with universal functionality to drive the planetary gear system independently. Each motor can serve as the primary drive or the backup drive, and either motor can be braked when not in use. This multi-functionality allows the system to maintain high reliability through redundancy while managing complexity by having identical, interchangeable components
Solution Approach 2:
The control systems of both motors are merged through a common brake mechanism and shared planetary gear system. This merging allows simplified control logic where the same brake can be applied to either motor, and the same gear system receives input from either motor, thereby improving reliability through redundancy while preventing excessive complexity increase through shared components
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 solution enhances the reliability and longevity of linear actuators by allowing motor alternation and redundancy, ensuring continuous operation even if one motor fails, and enables efficient conversion of rotary motion to linear displacement.
Implementation Method 1
a planetary gear system including a sun gear, a ring gear, and a planet carrier
Implementation Method 2
braking the other of the first motor or the second motor
Data Source
AI summary
A linear actuator includes a planetary gear system includes a sun gear, a ring gear, and a planet carrier. A linear output mechanism is coupled to the planetary gear system. A first motor is configured to drive a first input shaft, and the first input shaft is coupled to the planet carrier. A second motor is configured to drive a second input shaft, and the second input shaft is coupled to the ring gear. A first brake is coupled to the first motor and is configured to be engaged into a braked position that holds the planet carrier fixed. In the braked position, rotation of the ring gear results in rotation of the sun gear for linear displacement of the linear output mechanism.