Surgical End Effector Arm Gravity Compensation With Variable Spring
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Solution Overview
Problem
Conventional surgical guidance systems for robotic surgery, such as those used in total knee arthroplasty, face challenges in maintaining precision and reducing surgeon fatigue due to the weight of the end effector arm, especially when the resection plane is inclined or vertical, leading to undesirable strain and stress on the surgeon's hand.
Innovation Solution
An end effector arm with a spring mechanism that imparts a variable rotational force based on the angle of rotation, compensating for gravitational forces across a range of angles, thereby reducing the need for the surgeon to support the weight of the system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the end effector arm uses aluminum structural parts to reduce weight and manufacturing cost, then manufacturing cost and weight are reduced, but gravitational force causes undesirable strain on the surgeon's hand during inclined or vertical resections
Solution Approach 1:
The patent applies the anti-weight principle by introducing a spring mechanism that generates an opposing force to counteract the gravitational force acting on the end effector arm. The spring mechanism is configured to apply a force equal and opposite to the gravitational force, thereby compensating for the weight of the aluminum structural parts and eliminating the strain on the surgeon's hand during inclined or vertical resections.
Solution Approach 2:
The patent employs parameter changes by making the spring mechanism adjustable to accommodate different resection angles and configurations. The spring force can be modified to match the gravitational force at various angles, allowing the system to maintain optimal performance across different surgical scenarios while using lightweight aluminum construction.
2Manufacturing precision
If the end effector arm is designed with high transverse stiffness for resection accuracy, then manufacturing precision is improved, but the weight of the arm increases causing surgeon fatigue
Solution Approach 1:
The spring mechanism serves as a counterweight system that compensates for the weight of the stiff aluminum structure. By applying an equal and opposite force, the spring mechanism allows the end effector arm to maintain high transverse stiffness for accurate resections without transmitting the full weight to the surgeon's hand, thus preventing fatigue.
Solution Approach 2:
The patent effectively creates a composite system combining aluminum structural parts with spring mechanism components. This composite approach allows the aluminum parts to provide the necessary stiffness and strength for manufacturing precision, while the spring mechanism compensates for the weight, achieving both resection accuracy and reduced surgeon fatigue.
3Adaptability or versatility
If the resection plane is inclined or vertical to access difficult surgical sites, then adaptability is improved, but the gravitational force on the end effector arm increases causing surgeon fatigue
Solution Approach 1:
The spring mechanism provides continuous gravitational compensation that adapts to different resection plane orientations. Whether the resection is horizontal, inclined, or vertical, the spring force adjusts to counteract the component of gravitational force acting on the end effector arm, allowing the surgeon to operate comfortably across all orientations without hand strain.
Solution Approach 2:
The spring mechanism introduces dynamic adaptability to the end effector arm system. The spring force automatically adjusts based on the orientation and position of the arm, providing real-time compensation for gravitational effects. This dynamic response enables the system to maintain optimal performance across varying resection planes without requiring manual adjustment by the surgeon.
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
Enhances precision in surgical cuts and reduces surgeon fatigue by dynamically balancing the weight of the end effector arm, ensuring consistent guidance and stability during inclined or vertical resections.
Implementation Method 1
a spring mechanism configured to impart a variable rotational force on the mechanical linkage based on an angle of rotation of the mechanical linkage with respect to the base
Data Source
AI summary
An end effector arm for use with a surgical navigation system includes a base configured to attach to an end effector coupler of a surgical robot arm and a mechanical linkage. The mechanical linkage includes a first end rotatably coupled to the base and a second end opposite the first end, the second end configured to be removably coupled to a handheld surgical tool. The end effector arm further includes a spring mechanism configured to impart a variable rotational force on the mechanical linkage based on an angle of rotation of the mechanical linkage with respect to the base.