Medical Support Arm Gravity Compensation Without Counterweights
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Solution Overview
Problem
Existing medical support arm apparatuses with counterweights are bulky, heavy, and cumbersome, impeding surgical space and requiring significant installation efforts, while their inertia complicates rapid and comfortable operation.
Innovation Solution
A medical support arm apparatus configured without a counterweight, utilizing actuators and encoders to achieve six degrees of freedom, enabling gravity compensation, position fine movement, and pivot operations, allowing compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a counterweight is provided on the base end side of the arm section to balance the weight, then the arm section can be supported and positioned with high precision, but the apparatus becomes bulky and heavy, dominating the operating room space and requiring large-scale construction work for installation
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with an active control system using actuators (motors) and sensors (encoders, torque sensors). The control unit calculates required torque based on arm section position and weight distribution, then commands actuators to provide precise counterbalancing force electronically, eliminating the need for bulky physical counterweights while maintaining positioning precision.
Solution Approach 2:
The system dynamically adjusts the balancing torque parameter based on real-time detection of arm section position and configuration. The control unit continuously calculates and modifies the required counterbalancing force according to changing arm positions and attached tool weights, enabling precise control without fixed mechanical counterweights.
2Weight of moving object
If a counterweight is provided to balance the arm section, then the weight can be supported, but the overall apparatus weight increases, requiring large-scale construction work and increasing installation costs
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with an active control system using actuators (motors) and sensors (encoders, torque sensors). The control unit calculates required torque based on arm section position and weight distribution, then commands actuators to provide precise counterbalancing force electronically, eliminating the need for bulky physical counterweights while maintaining positioning precision.
3Weight of moving object
If a counterweight is provided on the base end side of the arm section, then the weight may be supported, but the inertia becomes large, making it difficult to operate the front end rapidly and comfortably
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with an active control system using actuators (motors) and sensors (encoders, torque sensors). The control unit calculates required torque based on arm section position and weight distribution, then commands actuators to provide precise counterbalancing force electronically, eliminating the need for bulky physical counterweights while maintaining positioning precision.
Solution Approach 2:
The system provides dynamic torque adjustment that adapts to changing operational conditions. The control unit continuously monitors arm position and velocity, and adjusts the counterbalancing torque in real-time to maintain optimal operability throughout the range of motion, enabling both precise positioning and rapid movement when needed.
4Stability of the object's composition
If the support arm apparatus is configured as a balance arm with counterweight, then the arm section is balanced overall, but the apparatus becomes bulky and the surgical work may be impeded
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with an active control system using actuators (motors) and sensors (encoders, torque sensors). The control unit calculates required torque based on arm section position and weight distribution, then commands actuators to provide precise counterbalancing force electronically, eliminating the need for bulky physical counterweights while maintaining positioning precision.
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 apparatus maintains operability and precision without bulk, reducing installation costs and improving ease of operation, enabling intuitive control and efficient use of surgical space.
Implementation Method 1
a drive unit including: an actuator that generates torque in association with rotation about the rotation axis
Implementation Method 2
a rotary encoder that detects a rotational angle in association with rotation about the rotation axis
Implementation Method 3
the control unit calculates a torque necessary for rotating the arm section about the rotation axis in accordance with a gravity compensation operation
Data Source
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AI summary
To make it possible to configure a medical support arm apparatus which does not impair operability for the surgeon, and which is also compact. Provided is a medical support arm apparatus including: an arm section configured so that a medical tool is provided on a front end, and movable axes are arranged so that the arm section has at least six degrees of freedom. Among the movable axes, a movable axis provided on the front end side that prescribes an attitude of the medical tool is a passive axis that rotates by following an external force, and at least one axis provided on a base end side that prescribes a position of the medical tool is a drive axis driven by an actuator.