Robotic Surgical End Effector Grip Force Locking for Stability
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Solution Overview
Problem
Robotically-controlled surgical instruments face challenges in controlling gripping force, leading to unintended movements and instability during procedures, as surgeons may inadvertently apply higher gripping forces than necessary, affecting the precision and effectiveness of minimally invasive surgeries.
Innovation Solution
A method to control the gripping force of a surgical instrument's end effector by receiving specific input signals from a surgeon console, allowing for adjustable gripping force levels, with a servo motor torque mechanism to increase the force only during procedures requiring higher grip, and locking degrees of freedom to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high gripping force is applied to ensure adequate tissue contact for sealing and cutting procedures, then the reliability of surgical procedures is improved, but unintended movements and instability occur during procedures
Solution Approach 1:
The system dynamically adjusts the gripping force level based on the detected surgical procedure type. The control system transitions between different gripping force states (first level for sealing/cutting, second level for other procedures) to optimize both reliability and stability for each specific procedure
Solution Approach 2:
The control system uses feedback from detecting the surgical procedure type to automatically adjust the gripping force. By monitoring what procedure is being performed and responding with appropriate force levels, the system maintains stability while ensuring adequate contact force for each procedure type
2Stability of the object's composition
If automatic control of gripping force is implemented to prevent unintended movements, then the stability of end effector is improved, but the device complexity increases
Solution Approach 1:
The control system is pre-programmed with knowledge of different surgical procedures and their required gripping force levels. When a procedure is detected, the system automatically retrieves and applies the appropriate pre-determined force level, simplifying the control logic while maintaining stability
Solution Approach 2:
The system changes the gripping force parameter based on the detected procedure type. By automatically adjusting this single critical parameter according to procedure requirements, the system achieves stability without requiring complex mechanical modifications or multiple control systems
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 approach enables precise control of gripping forces, minimizing tissue damage and maintaining stability during procedures, ensuring accurate execution of surgical tasks by limiting high gripping forces to necessary operations and locking movements accordingly.
Implementation Method 1
servo-actuators (e.g., servo motors), can be used to transmit force or torque to various components that ultimately transmit from a transmission mechanism that interfaces with the patient side manipulator down the shaft and to the end effector
Implementation Method 2
a spring assembly in the transmission backend to transmit and control the torque from the servomotor that ultimately acts to actuate the end effector
Data Source
AI summary
A computer-assisted surgical system comprises a master grip input mechanism, a surgical instrument comprising an end effector configured to apply a gripping force, and a controller. The controller is configured to receive a first input signal in response to grip input at the master grip input mechanism. The controller is further configured to receive a second input signal after receiving the first input signal, wherein the second input signal is received in response to a procedure input at a master input device, with the procedure input being different from the grip input at the master grip input mechanism and further being indicative of a user's readiness to operate the surgical instrument to perform a first surgical procedure. The controller is further configured to, in response to receiving the first input signal and the second input signal, cause one or more degrees of freedom of the surgical instrument to be placed in a locked state.