Surgical Instrument Force Sensor for Precision Feedback
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Solution Overview
Problem
Current robotically-assisted surgical systems lack accurate force feedback to surgeons, leading to inconsistencies in force measurement across different surgical instruments and increased costs due to the need for high-resolution torque sensors and sensitive elements that are prone to noise and environmental variations.
Innovation Solution
A surgical instrument with a mechanical structure featuring a sleeve and a force sensor that includes sensitive elements and a peripheral measurement module to accurately measure contact forces on the terminal end, allowing for precise calculation of both resultant force and moment, and enabling reusable sensitive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors with high measurement accuracy and resolution are used to detect minor contact forces, then measurement precision is improved, but the system becomes sensitive to noises, causes signal distortions, and results in expensive costs
Solution Approach 1:
The patent introduces a force sensor as an intermediary device that directly measures contact forces at the terminal end of the surgical instrument. This force sensor acts as a mediator between the surgical instrument and the control system, providing accurate force measurements without requiring high-resolution torque sensors at the robotic arm joints. The force sensor includes a sensitive element that directly detects contact forces, converting them into measurable signals.
Solution Approach 2:
The patent replaces the traditional mechanical torque sensing system (which relies on torque sensors at robotic arm joints) with a direct force sensing approach using a force sensor at the instrument terminal. This substitution eliminates the need for complex torque measurement and calculation chains, directly measuring the contact force of interest with simpler and more cost-effective sensing technology.
2Measurement precision
If strain sensitive elements are embedded in each surgical instrument terminal end, then direct force measurement is achieved, but measurement consistency across different instruments becomes difficult to ensure and sensor costs increase
Solution Approach 1:
The patent creates a universal force sensor design that can be applied to multiple surgical instruments. The force sensor with its sensitive element serves as a standardized component that can be integrated into different instrument types, ensuring measurement consistency across the instrument library. This universal approach allows for standardized calibration and measurement protocols to be applied across all instruments using the force sensor.
Solution Approach 2:
The patent addresses environmental sensitivity by implementing parameter compensation and calibration mechanisms. The system monitors and compensates for variations in sensitive element properties caused by temperature, humidity, and atmospheric pressure changes. Through parameter adjustment and calibration procedures, the system maintains measurement consistency and reliability across different environmental conditions and instrument uses.
3Duration of action of stationary object
If surgical instruments are equipped with reusable sensors, then measurement capability is maintained, but the cost increases when instruments need to be scrapped along with sensors
Solution Approach 1:
The patent segments the surgical instrument system into reusable and disposable components. The force sensor is designed as a separate, reusable component that can be detached from the disposable surgical instrument. This segmentation allows the expensive sensor to be recovered and reused while the instrument itself can be discarded after use, optimizing the lifecycle management of both components.
Solution Approach 2:
The patent implements a recover and reuse strategy for the force sensor. After the surgical instrument is used and potentially discarded, the force sensor is recovered from the instrument for continued use on future procedures. This approach maximizes the utilization of the expensive sensing component, reducing overall system costs and minimizing waste of critical measurement capabilities.
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
This solution enhances measurement accuracy, reduces instrument-specific calibration needs, and avoids unnecessary sensor scrappage, providing a more precise and cost-effective force feedback system for surgical robots.
Implementation Method 1
the sensitive element is disposed on the sleeve and configured to obtain a strain information of the sleeve
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~5a
AI summary
The present invention provides a surgical robot system and a surgical instrument thereof, which can measure a contact force acting on a terminal end of the surgical instrument with enhance precision and accuracy. The surgical instrument includes a mechanical structure, a sleeve and a force sensor. The mechanical structure includes a shaft and an end effector connected to a terminal end of the shaft. The sleeve fixedly or detachably sleeves over the terminal end of the shaft. The force sensor includes a sensitive element and a peripheral measurement module connected thereto. The sensitive element is arranged on the sleeve and configured to acquire strain information of the sleeve. The peripheral measurement module is configured to obtain stress measured by the sensitive element based on the strain information acquired thereby, and to obtain both an equivalent resultant force and an equivalent resultant moment of an action force exerted by the shaft on the sleeve based on the stress measured by the sensitive element, the position of the sensitive element and the direction of the sensitive axis of the sensitive element, thereby obtaining a contact force acting on the end effector of the surgical instrument.