Variable Duration Trigger for Surgical Motor Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motorized surgical stapling and cutting instruments face challenges in controlling the velocity of cutting members and articulation velocity of end effectors, leading to potential maximum current exceeding limits and noise-induced errors, which can affect tissue handling and instrument performance.
Innovation Solution
A surgical instrument with a displacement member, motor, control circuit, parameter sensor, and position sensor that determines the duration of force or current above a threshold and adjusts motor control actions based on position, ensuring precise control and preventing excessive current spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the current limit is triggered by instantaneous exceeding during a predefined zone, then the velocity control precision is improved, but the reliability deteriorates due to noise-induced false triggering
Solution Approach 1:
The patent applies dynamics by making the time period variable rather than fixed. The control circuit adjusts the time period based on the position of the cutting member or anvil within the firing stroke or closure stroke. This dynamic adjustment allows the system to use shorter time periods (more sensitive) during critical zones where velocity control precision is needed, and longer time periods (less sensitive) during other zones to prevent noise-induced false triggering, thus resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The patent changes the parameter of time period duration based on operational context. By modifying the time period parameter dynamically according to the position within the stroke, the system optimizes the balance between detecting genuine current exceeds (for velocity control) and filtering out noise (for reliability). This parameter change strategy directly addresses the contradiction by adapting the detection sensitivity to the operational phase
2Device complexity
If a fixed time period is used for triggering events, then the device complexity is reduced, but the velocity control precision deteriorates due to inability to adapt to different stroke regions
Solution Approach 1:
The control circuit dynamically adjusts the time period parameter based on the detected position of the cutting member or anvil. This dynamic behavior adds functional capability without requiring multiple separate circuits, maintaining relatively simple device architecture while achieving adaptive velocity control precision across different stroke regions
Data Source
AI summary
A motorized surgical instrument is disclosed. The surgical instrument includes a displacement member, a motor coupled to displacement member, a control circuit coupled to the motor, a parameter sensor coupled to the control circuit and a position sensor coupled to the control circuit. The control circuit is configured to receive a parameter output of the parameter sensor indicative of a force applied to translate the displacement member, determine a duration during which the parameter output is maintained at or above a predetermined fault threshold, receive a position output of the position sensor indicative of at least one position of the displacement member during the duration, and effect a motor control action based on the duration and the at least one position.