Rack and Pinion Actuated Surgical Robot Arm
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Solution Overview
Problem
Current surgical robots with bendable arms for minimally invasive surgery face challenges in achieving sufficient stability and force while maintaining mechanical simplicity and efficiency, often requiring complex mechanisms or cables/wires for bending, which can be cumbersome and prone to failure under expected loads.
Innovation Solution
A bendable robot arm design utilizing a rack and pinion pairing, where a rack member on the proximal arm segment moves longitudinally to mesh with pinion teeth on the distal arm segment, converting linear movement into rotational movement, providing stability and force without the need for cables or wires, and allowing for reliable bending and additional degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cables or wires are used for bending the robot arm, then the robot arm can achieve flexibility and bending movement, but the mechanical complexity increases and reliability decreases due to being cumbersome and prone to failure under expected loads
Solution Approach 1:
The patent removes cables and wires from the robot arm structure entirely, extracting the problematic flexible transmission elements that caused reliability issues. Instead, it uses a rigid rack-and-pinion mechanism that achieves bending through rotational movement of the distal segment, eliminating the sources of failure while maintaining adaptability.
Solution Approach 2:
The patent replaces the cable/wire-based flexible transmission system with a rigid mechanical rack-and-pinion system. This substitution transforms the bending mechanism from flexible element deformation to rigid body rotational movement, significantly improving reliability under surgical loads while maintaining the desired adaptability.
2Strength
If complex mechanisms are used to achieve sufficient stability and force, then the robot arm can handle expected loads, but the mechanical complexity increases
Solution Approach 1:
The patent combines the bending mechanism and actuation system into a single integrated rack-and-pinion unit. The rack element on the proximal segment directly engages with pinion teeth on the distal segment, merging what could have been separate complex mechanisms into one simple, efficient system that provides both stability and force capability.
Solution Approach 2:
Instead of using flexible elements that bend under load, the patent inverts the approach by using rigid elements that rotate. The distal arm segment rotates relative to the proximal segment through the rack-and-pinion mechanism, achieving bending movement through rigid body rotation rather than flexible deformation, thereby simplifying the overall mechanism.
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 rack and pinion mechanism offers sufficient stability and force for minimally invasive surgery while reducing mechanical complexity and material costs, enabling reliable bending and movement of the robot arm, even under expected loads, with the option for additional movements using cables or wires.
Implementation Method 1
A rack element (12) is arranged on the proximal arm segment (1) such that the rack element (12) is movable in the longitudinal direction of the rack element (12) parallel to the longitudinal axis by means of a translation, and rack teeth (11) formed on the rack element (12) engage with the pinion teeth (10)
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
According to the disclosure, an articulated robotic arm for minimally invasive surgery is provided. The robotic arm has a proximal arm segment (1) extending along a longitudinal axis of the robotic arm and a distal arm segment (2) pivotably connected to the proximal arm segment (1) about a pivot axis orthogonal to the longitudinal axis. The distal arm segment (2) has a pinion segment formed with pinion teeth arranged around the pivot axis in the form of a pinion.A rack and pinion element (12) is arranged on the proximal arm segment (1) such that the rack and pinion element (12) is movable in the longitudinal direction parallel to the longitudinal axis by means of translation, and the rack teeth formed on the rack and pinion element (12) engage with the pinion teeth, so that a movement of the rack and pinion element (12) in the longitudinal direction via the rack teeth and the pinion teeth is converted into a rotational movement of the distal arm segment (2) about the pivot axis, and the distal arm segment (2) pivots relative to the proximal arm segment (1) about the pivot axis. Furthermore, a method for manufacturing an articulated robot arm and a surgical robot are provided.