Parallel Leaf-Spring Rotation Mechanism for Precise 2-DOF Motion
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Solution Overview
Problem
Existing multi-degree-of-freedom manipulators face issues with wire-based power transmission, including frequent wire replacement, limited control precision, difficulty in sterilization, and increased maintenance costs, as well as challenges with size, weight, and cost due to complex link mechanisms, which hinder effective operation in narrow spaces like laparoscopic surgery.
Innovation Solution
A two-degree-of-freedom rotation mechanism using parallel springs with a simple structure, comprising a base body, links, and leaf springs, which converts independent linear motions into two-degree-of-freedom operations, allowing precise and space-efficient motion support while being lightweight, cost-effective, and easy to sterilize.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire is used for power transmission, then power can be transmitted from driving device, but wire needs frequent replacement and maintenance
Solution Approach 1:
The patent replaces the wire-based mechanical power transmission system with a link mechanism system. Instead of using flexible wires that expand and contract requiring frequent replacement, rigid links with rotational joints provide stable mechanical power transmission. The link mechanism eliminates wire-related issues such as elongation, breaking, and control precision limitations while maintaining the ability to transmit power from the driving device to the manipulator joints.
Solution Approach 2:
The power transmission system is divided into multiple rigid link segments connected by rotational joints, rather than using a continuous flexible wire. Each link segment is structurally independent and can be precisely manufactured, eliminating the need for frequent wire replacement while maintaining flexibility in motion control through the segmented link structure.
2Reliability
If link mechanism is used for power transmission, then power can be transmitted from driving device, but number of parts increases and size increases
Solution Approach 1:
The patent merges multiple link segments and driving mechanisms into an integrated manipulator structure where links serve dual purposes as both structural components and power transmission elements. The rotational joints at link connections serve both as mechanical couplings and as controlled degrees of freedom, reducing the number of separate parts compared to traditional wire-driven systems with multiple pulleys and tensioning mechanisms.
Solution Approach 2:
Each link in the mechanism performs multiple functions: it transmits mechanical power from the driving device, provides structural support for the manipulator, defines the geometric constraints for motion, and serves as a mounting structure for other components. This multi-functionality reduces the overall number of parts needed compared to specialized wire-driven systems.
3Power
If wire is used for power transmission, then power can be transmitted, but control precision is limited due to expansion and contraction
Solution Approach 1:
The patent replaces the flexible wire transmission system with rigid link mechanisms that eliminate the expansion and contraction problems inherent in wire-based systems. The rigid links maintain precise geometric relationships throughout motion, enabling accurate control of joint positions and orientations without the elasticity-induced errors that limit wire-driven system precision.
4Reliability
If wire is used for power transmission, then power can be transmitted, but sterilization and cleaning become complicated
Solution Approach 1:
The patent replaces the wire-based system with a link mechanism consisting of rigid, solid components that can be easily sterilized and cleaned. Unlike wires that may fray, absorb fluids, or have complex surface geometries difficult to sterilize, the link mechanism components have smooth, solid surfaces that can withstand standard sterilization procedures, making them suitable for medical and surgical applications.
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 mechanism provides precise, cost-effective, and space-efficient two-degree-of-freedom operations with reduced burden on the target, enabling applications in manipulators and forearm motion support devices, enhancing sterilization properties and reducing maintenance needs.
Implementation Method 1
a first leaf spring of a rectangular shape of which a longitudinal base end is connected to a tip of the first link as a rotation pair... a second leaf spring of a rectangular shape of which a longitudinal base end is connected to a tip of the second link as a rotation pair
Data Source
AI summary
A manipulator includes a base body, a first link supported to be capable of advancing and retracting with respect to the base body, a first leaf spring connected to a tip of the first link as a rotation pair by a first base end pin, a second link that is arranged with the first link side by side and is supported to be capable of advancing and retracting with respect to the base body, a second leaf spring connected to a tip of the second link as a rotation pair by a second base end pin in the same direction as the first base end pin, and a driven link that is connected to tips of the first and second leaf springs as rotation pairs by first and second tip pins in the same direction as the first and second base end pins, respectively.