Robotic Surgical Stapler Motor Control Algorithm
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Solution Overview
Problem
Current surgical staplers in robotic surgical systems face challenges in efficiently controlling motor operations, particularly in overcoming frictional binding and preventing overheating, which can lead to inadequate performance during tissue stapling and cutting procedures.
Innovation Solution
The implementation of a multi-threshold motor control algorithm that uses sensor data to adjust motor control parameters, such as power and speed, to prevent overheating and minimize frictional binding by modifying the motion profile and using algorithmic bumping techniques to ensure effective stapling and cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor operates at high power to overcome frictional binding, then the stapling and cutting performance is improved, but the motor overheats and reliability deteriorates
Solution Approach 1:
The motor control algorithm implements periodic action by using a multi-threshold control system that cycles through different power levels based on real-time feedback from current, temperature, and position sensors. The controller alternates between high-power modes (for overcoming frictional binding and performing stapling/cutting) and low-power modes (for cooling and maintaining operation), preventing continuous overheating while ensuring adequate performance when needed.
Solution Approach 2:
The system employs feedback control by continuously monitoring motor current, temperature, and position through sensors, and using this data to dynamically adjust motor control parameters. The multi-threshold algorithm compares real-time sensor readings against predefined thresholds and modifies power delivery accordingly, creating a closed-loop control system that prevents overheating while maintaining reliability during high-demand operations.
2Productivity
If the motor speed is increased to improve productivity, then the stapling and cutting efficiency is improved, but frictional binding increases causing harmful effects
Solution Approach 1:
The motor control algorithm implements dynamics by continuously adapting motor speed and torque based on real-time operating conditions. Rather than maintaining a fixed high speed, the system dynamically adjusts velocity profiles according to tissue characteristics, jaw position, and resistance forces detected by sensors. This dynamic control allows the motor to operate at high speeds during low-resistance phases while reducing speed during high-friction periods, maintaining productivity while minimizing frictional binding and harmful effects.
Solution Approach 2:
The system applies parameter changes by modifying multiple motor control parameters simultaneously - including speed, acceleration, torque, and duty cycle - based on multi-threshold conditions. The algorithm changes these parameters in response to sensor feedback about tissue density, jaw closure force, and motor temperature, optimizing the balance between productivity and friction generation throughout the stapling and cutting cycle.
Data Source
AI summary
A method of operating a robotically controlled surgical instrument that includes an end effector, a driving assembly, and a lockout, the method includes inhibiting actuation of the driving assembly when the lockout is in a locked configuration in response to an unspent staple cartridge being absent from a first jaw of the end effector. The method also includes inserting the unspent staple cartridge into the first jaw of the end effector to switch the lockout to an unlocked configuration. The method also includes actuating the driving assembly to pivot the first jaw, which includes the staple cartridge, toward a second jaw of the end effector to at least one of staple or cut tissue with the end effector when the lockout is in the unlocked configuration.