Low Backlash Actuator Interface for Surgical Instruments
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Solution Overview
Problem
Surgical instruments with robotically controlled systems face challenges in minimizing backlash, which affects the transmission of controlled torque and position, leading to unpredictable instrument movement during installation, especially in confined spaces.
Innovation Solution
A surgical system with a low backlash mechanical interface that includes a drive unit, drive output assembly, and preload springs to ensure zero backlash for torque levels used in surgical procedures, utilizing a combination of alignment elements and preload forces to securely engage disks and prevent unwanted motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical interface is used to couple drive units to surgical instruments, then torque and position can be transmitted, but backlash occurs causing unpredictable instrument movement
Solution Approach 1:
The patent applies preliminary action by pre-loading the mechanical interface with springs before operation. The preload force is applied in advance to eliminate backlash, ensuring that when torque is transmitted during surgical procedures, the interface maintains zero backlash and predictable movement without requiring adjustment during actual use.
2Manufacturing precision
If alignment elements are added to ensure proper engagement of disks, then positioning accuracy improves, but device complexity increases
Solution Approach 1:
The patent employs asymmetry in the alignment elements, using asymmetric features on the disks that guide engagement in a specific orientation. This asymmetric design ensures precise alignment during installation while requiring only a few strategically placed elements rather than multiple symmetric features, thereby maintaining positioning accuracy without excessive complexity.
3Manufacturing precision
If preload force is applied to eliminate backlash, then torque transmission accuracy improves, but the risk of damaging delicate components increases
Solution Approach 1:
The patent applies parameter changes by carefully selecting and adjusting the preload force magnitude to be sufficient for backlash elimination but limited to prevent damage. The spring constants and preload distances are optimized so that the force is high enough to maintain zero backlash during torque transmission yet low enough to protect delicate surgical instrument components from excessive stress.
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 effectively minimizes backlash, ensuring precise and predictable instrument movement, enhancing the reliability and accuracy of surgical procedures by maintaining zero backlash for torque levels used in surgical procedures.
Implementation Method 1
drive output assembly, and preload springs to ensure zero backlash for torque levels used in surgical procedures
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A surgical system (200) includes a surgical instrument (260) that is sensitive to backlash that would adversely affect the transmission of controlled torque and position to the surgical instrument. The surgical instrument (260) is coupled to motors in a surgical instrument manipulator assembly (240) via a mechanical interface. The combination of the mechanical interface and surgical instrument manipulator assembly (240) have low backlash, e.g., less than 0.7 degrees. The backlash is controlled in the surgical instrument manipulator assembly (240). From the drive output disk (545) in the surgical instrument manipulator assembly to the driven disk (964) of the surgical instrument, the mechanical interface has zero backlash for torque levels used in surgical procedures.