Shared-Link Actuator Linkage for Redundant Motion Control
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Solution Overview
Problem
Existing redundant actuator systems face challenges in efficiently controlling multiple degrees of freedom and handling actuator failures, such as jamming or open failures, while minimizing backlash and maintaining mechanical advantage.
Innovation Solution
The actuator system employs a shared link and two actuators with independent degrees of freedom, allowing for simultaneous power application to rotate the controlled element while maintaining one degree of freedom constant, and includes a brake and spring-damper configuration to handle failures and adjust mechanical advantage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple actuators are arranged to sum displacement or torque, then redundancy is achieved, but control complexity and device complexity increase
Solution Approach 1:
The system divides the control function into two independent actuators (first actuator 140 and second actuator 141), each controlling a separate degree of freedom (first variable distance L1 and second variable distance L2). This segmentation allows independent control of each actuator while maintaining redundancy, reducing the complexity of controlling multiple actuators simultaneously.
Solution Approach 2:
The shared link 121 and controlled element 125 serve multiple functions: they are common to both actuator systems, allowing either actuator to independently control the controlled element. This multi-functionality enables redundancy without requiring separate complete actuation systems, thereby reducing overall device complexity.
2Adaptability or versatility
If actuators are configured to control multiple degrees of freedom, then versatility is improved, but ease of operation deteriorates
Solution Approach 1:
The system dynamically configures the linkage geometry through variable distances L1 and L2, allowing the mechanical advantage and control characteristics to change in real-time. This dynamic adjustment simplifies operation by adapting the system to different operational requirements, making it easier to control despite having multiple degrees of freedom.
Solution Approach 2:
The shared link 121 acts as an intermediary between the two actuators and the controlled element 125. It mediates the interaction between the two independent actuation systems, allowing either actuator to independently control the controlled element while maintaining coordinated operation, thereby simplifying the operator's task.
3Manufacturing precision
If linkage geometry is fixed, then manufacturing precision is improved, but adaptability deteriorates
Solution Approach 1:
The linkage geometry is made dynamic through the variable distances L1 and L2, which can be adjusted while maintaining precise control. This allows the system to adapt its mechanical advantage and control characteristics to different operational requirements without sacrificing manufacturing precision in the base linkage structure.
Solution Approach 2:
The system changes the geometric parameters L1 and L2 to adjust the mechanical advantage and control characteristics. By varying these parameters, the system can adapt to different operational conditions while maintaining precise control over the controlled element, resolving the contradiction between fixed geometry and adaptability.
4Power
If hydraulic systems are used, then power is improved, but weight and energy consumption increase
Solution Approach 1:
The patent replaces hydraulic actuation systems with electromechanical actuators (first actuator 140 and second actuator 141). This substitution eliminates the need for hydraulic fluid, pumps, and associated heavy infrastructure, significantly reducing system weight while maintaining adequate power delivery through direct electromagnetic actuation.
Solution Approach 2:
The invention extracts and removes the hydraulic system components (fluid, pumps, reservoirs) from the actuation system, retaining only the essential electromechanical actuators. This extraction eliminates the weight penalty associated with hydraulic systems while preserving the core power delivery function through more efficient electromagnetic actuation.
Data Source
AI summary
An actuator system comprising a shared link arranged to pivot about a first axis relative to a reference structure, a controlled element arranged to pivot about a second axis relative to the reference structure, a first member arranged to pivot about a third axis relative to the shared link and a fourth axis relative to the controlled member, a first actuator arranged to control a first variable distance between the third axis and fourth axis, a second member arranged to pivot about a fifth axis relative to the shared link and a sixth axis relative to the controlled element, a second actuator arranged to control a second variable distance between the fifth axis and the sixth axis, the system configured such that a change in the first variable distance causes rotation of the controlled element about the second axis when the second variable distance is constant and vice versa.