Surgical Stapler Motor Velocity Control via Articulation Angle
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Solution Overview
Problem
Existing motorized surgical stapling and cutting instruments face challenges in controlling the velocity of the cutting member and articulation velocity of the end effector, particularly as the articulation angle increases, leading to varying forces required for firing or loading.
Innovation Solution
A surgical instrument with a displacement member, a motor, a control circuit, and a position sensor that measures the position of the displacement member and the articulation angle of the end effector. The control circuit determines the articulation angle, sets motor velocity based on the angle, and adjusts the motor velocity when the force on the displacement member exceeds a selected force threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the articulation angle of the end effector increases, then the versatility and adaptability of the surgical instrument is improved, but the force required to fire or load the cutting member increases
Solution Approach 1:
The patent implements dynamic velocity control where the motor velocity is continuously adjusted based on the real-time articulation angle. As the articulation angle changes during operation, the control circuit modifies the motor velocity accordingly, allowing the system to adapt to varying force requirements dynamically rather than using a fixed velocity setting
Solution Approach 2:
The patent changes the operational parameters by varying motor velocity as a function of articulation angle. The control circuit modifies velocity parameters based on measured articulation angles, and this parameter adjustment directly addresses the force requirements at different articulation positions, reducing the force to fire load
2Productivity
If the motor velocity is increased to improve productivity, then the cutting and stapling operation speed is improved, but the force control precision deteriorates
Solution Approach 1:
The patent employs feedback control where the control circuit continuously monitors the articulation angle via the position sensor and uses this information to adjust motor velocity. This closed-loop feedback mechanism ensures that velocity adjustments are precisely controlled based on actual articulation conditions, maintaining force control precision while optimizing firing speed
Solution Approach 2:
The system transitions from static velocity control to dynamic velocity control where motor velocity is continuously adapted based on real-time articulation angle measurements. This dynamic adjustment allows the system to maintain optimal force control precision across varying speeds and articulation positions
3Force
If the motor velocity is decreased to reduce the force to fire load, then the force requirement is reduced, but the productivity and operation speed decrease
Solution Approach 1:
The patent optimizes the velocity parameter by establishing a velocity-profile that varies with articulation angle. Rather than using a uniformly low velocity, the control circuit adjusts velocity parameters to match the force requirements at each articulation position, maintaining high productivity where possible while reducing force requirements where necessary
Data Source
AI summary
A motorized surgical instrument is disclosed. The surgical instrument includes a displacement member, a motor, a control circuit, and a position sensor. The displacement member is configured to translate. The motor is coupled to the displacement member to translate the displacement member. The control circuit is coupled to the motor. A position sensor is coupled to the control circuit. The position sensor is configured to measure the position of the displacement member and to measure an articulation angle of an end effector relative to a longitudinally extending shaft. The control circuit is configured to determine the articulation angle between the end effector and the longitudinally extending shaft and set motor velocity based on the articulation angle.