Preloaded Surgical Instrument Interface for Zero-Backlash Coupling
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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, especially during the installation process due to unpredictable motion caused by misalignment of drive motors and instruments.
Innovation Solution
A surgical instrument manipulator assembly with a low backlash mechanical interface, featuring a drive output disk with alignment elements and preload springs, ensures zero backlash for torque levels used in surgical procedures by precisely aligning and securing the drive output disk with an intermediate disk, thereby stabilizing instrument movement during installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mechanical interface with gears or disks is used to couple drive motors to surgical instruments, then torque transmission is achieved, but backlash occurs affecting position precision
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 between mating surfaces, ensuring that when torque is transmitted during surgical operation, the interface maintains zero backlash and precise position control without requiring complex active compensation mechanisms.
2Reliability
If drive motors are rotated back and forth during installation to ensure engagement, then secure coupling is achieved, but unpredictable instrument motion occurs
Solution Approach 1:
The patent eliminates the need for post-installation motor rotation by incorporating alignment elements (such as alignment keys or tapered surfaces) that automatically guide and align the drive output disk with the instrument's driven disk during the coupling process. This preliminary alignment ensures reliable engagement without requiring erratic motion or rotation after installation, maintaining instrument stability throughout the installation procedure.
3Reliability
If a sterile barrier with adaptor is used between drive system and instrument, then sterility is maintained, but alignment precision is reduced
Solution Approach 1:
The patent incorporates alignment elements directly into the sterile adaptor assembly, such as alignment keys or precision-machined surfaces on the adaptor itself. These intermediary alignment features bridge the gap between the drive system and instrument while maintaining sterility, enabling precise alignment to be achieved through the adaptor without compromising either sterility or alignment accuracy.
4Ease of operation
If clear space is provided around instrument to accommodate random movements, then installation flexibility is improved, but surgical space requirements increase
Solution Approach 1:
The patent eliminates the need for clear space around the instrument during installation by implementing preliminary alignment through alignment elements. These elements ensure that the drive output disk and instrument driven disk are precisely aligned during coupling, preventing random movements and eliminating the requirement for additional surgical space, thereby maintaining both installation flexibility and space efficiency.
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 stable transmission of torque and position, reducing unpredictable motion and enhancing the reliability of surgical instrument installation and operation.
Implementation Method 1
The combination of the mechanical interface and surgical instrument manipulator assembly has a low backlash, e.g. less than 0.7 degrees. The mechanical interface couples a drive interface in the surgical instrument manipulator assembly to a driven interface of the surgical instrument. The mechanical interface has zero backlash for torque levels used in surgical procedures
Data Source
AI summary
A surgical system includes a surgical instrument that is sensitive to backlash that would adversely affect the transmission of controlled torque and position to the surgical instrument. The surgical instrument is coupled to motors in a surgical instrument manipulator assembly via a mechanical interface. The combination of the mechanical interface and surgical instrument manipulator assembly have low backlash, e.g., less than 0.7 degrees. The backlash is controlled in the surgical instrument manipulator assembly. From the drive output disk in the surgical instrument manipulator assembly to the driven disk of the surgical instrument, the mechanical interface has zero backlash for torque levels used in surgical procedures.