Cable-Driven Robotic End Effector for Stable Needle Rotation
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Solution Overview
Problem
Developing a reliable endoscopic suturing device for robotic arms is challenging due to size, flexibility, driving part complexity, maintaining needle position and orientation, and transferring rotational movement within the patient's body, especially with limited instrument channels in flexible endoscopes.
Innovation Solution
A non-back driven cable driven gripper with a pull-pull mechanism using actuation wires to provide high gripping force and rotational motion, integrated into a robotic arm, featuring a gripper and rotary joint for endoscopic suturing, with a scalable design for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a robotic arm is made small and flexible to reach target position without hurting the patient, then the robot can access difficult-to-reach areas, but the robot loses the ability to manipulate the suturing needle firmly and maintain position and orientation
Solution Approach 1:
The robotic system is divided into a flexible robotic arm for navigation and a separate end effector for stable needle manipulation. The end effector includes a gripper mechanism with multiple degrees of freedom that can firmly grasp and orient the needle, compensating for the limited stability of the flexible arm.
Solution Approach 2:
A dedicated end effector acts as an intermediary between the flexible robotic arm and the suturing needle. This intermediate component provides the necessary mechanical stability and manipulation precision that the flexible arm alone cannot achieve.
2Device complexity
If the complexity and number of driving parts of the suturing mechanism is limited due to only one to two instrument channels, then the device can be used with current flexible endoscopes, but the robot cannot achieve precise control and rotational movement
Solution Approach 1:
Traditional mechanical cable-driven actuation is replaced with magnetic actuation. Magnets embedded in the end effector are controlled by external magnetic fields, enabling precise control of the gripper and needle orientation without requiring complex mechanical transmission through the endoscope channels.
Solution Approach 2:
The control mechanism changes from mechanical cable tension to magnetic field strength and orientation. By varying magnetic field parameters, the system achieves precise control over the end effector's position, gripper opening/closing, and needle orientation with minimal physical components.
3Ease of operation
If rotation along the endoscope's axis is implemented, then the gripping device can perform suturing motions, but transferring rotational movement from outside the patient's body becomes difficult
Solution Approach 1:
Mechanical rotational transmission through the endoscope is replaced with magnetic torque transmission. External magnetic fields generate rotational torque on magnets within the end effector, enabling rotation along the endoscope axis without mechanical connection or complex transmission mechanisms.
Solution Approach 2:
The end effector utilizes the flexibility of the endoscope while adding magnetic actuation capability. The magnetic components are integrated into the flexible structure, allowing rotation and manipulation at the distal end without rigid mechanical linkages.
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
The gripper provides precise and strong suturing capabilities, enabling minimally invasive procedures with improved control and reduced interference, suitable for endoscopic surgery and other applications.
Implementation Method 1
a first pair of actuation wires; wherein said first pair of actuation wires are connected to said at least one rotational member to actuate rotation with a pull-pull mechanism whereby tension and displacement in each wire of said first pair of actuation wires are same but direction is different
Data Source
AI summary
This invention provides an end-effector for robotic arms. In one embodiment, said adaptor comprises: a) a first housing having a center line; b) at least one rotational member with rotational axis perpendicular to said center line; c) a first pair of actuation wires; wherein said first pair of actuation wires are connected to said at least one rotational member to actuate rotation with a pull-pull mechanism whereby tension and displacement in each wire of said first pair of actuation wires are same but direction is different.