Controller Module for External Fixation Strut Adjustment
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Solution Overview
Problem
Existing external fixation systems face challenges in ease and precision of strut adjustment, particularly in achieving precise and controlled adjustments for bone deformity correction, with potential user errors in manual adjustments.
Innovation Solution
The system incorporates adjustable length struts with manual and automated modes of operation, allowing for discrete or infinitesimal length adjustments, and includes controller modules for automated actuation with infinitesimal adjustments, ensuring stable construction and precise bone deformity correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual actuation is used to adjust strut length, then the system is simple to operate, but the adjustment precision is limited to discrete increments
Solution Approach 1:
The strut assembly is designed to accept both manual actuation (providing simplicity) and automated controller module coupling (providing precision). The actuator can function in two modes: manual rotation for discrete adjustments or automated control for infinitesimal adjustments, making the system universal and adaptable to different operational requirements without needing separate systems.
2Measurement precision
If automated controller modules are coupled to struts, then adjustment precision increases to infinitesimal increments, but the system complexity increases
Solution Approach 1:
The same strut assembly serves both manual and automated functions. The controller module couples to the existing actuator mechanism rather than requiring a completely separate automated system, thereby reducing overall complexity while achieving high precision adjustment capability when needed.
Solution Approach 2:
The controller module acts as an intermediary between the control system and the mechanical strut assembly. It interfaces with the existing actuator components (strut gear, knob) to translate electrical control signals into precise mechanical adjustments, bridging the gap between digital control and mechanical adjustment without requiring complete system redesign.
3Extent of automation
If the strut knob is constrained in the first axial position, then discrete increment adjustments are maintained, but automated infinitesimal adjustments cannot be performed
Solution Approach 1:
The strut knob's axial position is made dynamic rather than fixed. It can be constrained in the first position for manual discrete adjustments or translated to the second position for automated infinitesimal adjustments. This dynamic reconfiguration allows the system to adapt its adjustment characteristics based on operational requirements, providing both discrete and continuous adjustment capabilities from the same hardware.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
An external fixation system (10) includes first and second fixation rings (20, 30) and a plurality of adjustable-length struts (200) that have two joints (210, 270), a rod (250), a tube (260), and an actuator (220) configured to drive the rod axially relative to the tube to change an effective length of the strut. The system has a plurality of controller modules (300) each configured to couple to a corresponding strut. In a manual mode of operation, the controller modules are not coupled to the struts, and manual actuation the actuators changes the effective lengths of the struts in discrete length increments. In an automated mode of operation, the controller modules are coupled to the struts and automated actuation of the actuators is configured to change the effective lengths of the struts in infinitesimally small length increments.