Fluid-Driven Piston Actuation for Robotic Surgical Instruments
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Solution Overview
Problem
Robotic surgical systems face challenges in efficiently actuating surgical instruments with precise control and articulation, particularly in translating rotational inputs into longitudinal motion and managing fluid flow for effective operation of end effectors like jaws and knives.
Innovation Solution
The actuation assembly includes a piston assembly that uses pressurized fluid to translate a driver mechanism, coupled with a lead screw assembly to convert rotational inputs into longitudinal motion, and features a flexible fluid line and biasing member to enable articulation and precise movement of end effectors, such as jaws and a deployable knife, within a surgical instrument attached to a robotic surgical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lead screw assembly is used to convert rotational inputs into longitudinal motion, then the precision of motion control is improved, but the device complexity increases
Solution Approach 1:
The patent employs a piston assembly with fluid lines to actuate the lead screw mechanism. Pressurized fluid is directed to the piston to generate the force needed to drive the lead screw, converting rotational motion into precise longitudinal motion of the surgical instrument. This hydraulic/pneumatic approach provides precise control while managing the complexity through fluid-powered actuation.
2Adaptability or versatility
If a flexible fluid line is used to allow articulation of the surgical instrument, then the adaptability is improved, but the reliability of fluid delivery may worsen
Solution Approach 1:
The patent utilizes a flexible fluid line that can articulate with the surgical instrument while maintaining fluid delivery. The flexible line is designed to bend and flex as the instrument articulates, allowing the surgical tool to reach different positions and angles while continuing to receive pressurized fluid for actuation.
3Ease of operation
If a biasing member is added to the piston assembly to enable two-way actuation, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The patent incorporates a biasing member (such as a spring) in the piston assembly that provides a restoring force to return the piston to its initial position after actuation. When pressurized fluid acts on the piston in one direction, the biasing member compresses; when fluid pressure is released, the biasing member expands to push the piston back, enabling automatic two-way actuation without requiring separate mechanisms for each direction.
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 enables precise and efficient actuation of surgical instruments, allowing for effective grasping, cutting, and articulation of tissue, improving the operational capabilities of robotic surgical systems by translating rotational inputs into controlled longitudinal motion and fluid-driven movements.
Implementation Method 1
positive actuation of the piston assembly urges pressurized fluid from the piston assembly along a fluid line
Implementation Method 2
negative actuation of the piston assembly allows the pressurized fluid to return to the piston assembly from the fluid line
Implementation Method 3
The actuation mechanism further includes a lead screw assembly configured to receive a rotational input and to convert the rotational input into longitudinal motion
Data Source
AI summary
An actuation assembly of a surgical instrument includes an actuation mechanism and an output mechanism. The actuation mechanism includes a piston assembly configured for positive and negative actuation. The output mechanism includes a fluid vessel in fluid communication with a fluid line connected to the piston assembly, a piston sealingly and slidably disposed within the fluid vessel, and a driver coupled to the piston. In response to positive actuation of the piston assembly, the pressurized fluid flows into the fluid vessel to move the piston to translate the driver in one direction. In response to negative actuation, the pressurized fluid exits the fluid vessel into the fluid line to allow the piston to translate the driver in an opposite direction.