Flexible Mechanical Joint for Robotic Head Articulation
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Solution Overview
Problem
Existing mechanical joints in robotics lack the flexibility to mimic human-like movement, particularly in allowing multiple degrees of freedom for articulation similar to a human neck, which restricts the range and naturalness of motion in robotic heads.
Innovation Solution
A flexible mechanical joint composed of disk-shaped links coupled by flexures distributed at 45-degree increments around a common axis, actuated by cables that control the joint's configuration and stiffness, enabling it to curl in any direction and mimic human-like tilting motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional mechanical joints are used, then the structure is simple and reliable, but the flexibility and range of motion are limited
Solution Approach 1:
The mechanical joint is divided into multiple disk-shaped links connected by flexures, allowing independent movement of each segment. This segmentation enables the joint to achieve complex curved trajectories and multiple degrees of freedom while maintaining a relatively simple overall structure.
Solution Approach 2:
The joint incorporates flexures that allow dynamic movement and adaptation of the mechanism's configuration. The cables provide variable actuation forces that can change the joint's stiffness and movement characteristics in real-time, enabling the system to adapt to different operational requirements.
2Adaptability or versatility
If multiple degrees of freedom are provided, then the range of motion increases, but the control complexity increases
Solution Approach 1:
The cable actuation system serves multiple functions simultaneously: it provides actuation forces for movement, controls the joint's stiffness, and can maintain positional stability. This multi-functionality reduces the need for separate control systems for each degree of freedom, simplifying the overall control architecture.
Solution Approach 2:
The joint's stiffness and movement characteristics are controlled by changing the tension parameters of the cables. By varying cable tension, the system can dynamically adjust its mechanical properties to match different operational requirements, enabling smooth transitions between different movement modes without complex control algorithms.
3Adaptability or versatility
If cables are used for actuation, then the flexibility and stiffness control improve, but the manufacturing precision requirements increase
Solution Approach 1:
The cable routing is designed to pass through holes in the centers of the disk links, creating a symmetric and balanced configuration. This equipotential arrangement ensures that cable forces are distributed evenly and predictably, reducing the sensitivity to minor manufacturing variations and simplifying the routing process.
Solution Approach 2:
The cable holes are pre-positioned at the centers of the disk links during manufacturing, establishing a precise reference framework before final assembly. This preliminary positioning ensures that cable routing aligns correctly without requiring high-precision adjustment during assembly, reducing manufacturing complexity.
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 flexible mechanical joint provides multiple degrees of freedom, allowing a robotic head to tilt similarly to a human head, enhancing the naturalness and range of motion while being actuated for various configurations and stiffness levels.
Implementation Method 1
The flexible mechanical joint is actuated through one or more cables, for instance a set of four cables. The cables may, for example, be distributed at four opposing corners of the links. The cables may be fixed to a last one of the links and pass through a number of throughholes in each of the links. Actuation (e.g., tensioning, relaxing) of the cables controls both a configuration (i.e., amount of curl about one or more axes) and a stiffness of the flexible mechanical joint.
Data Source
AI summary
A flexible joint includes a plurality of links, a plurality of flexures, and at least one cable which can be tensioned or relaxed to cause a bending about a plurality of axes. The links may include a base link; a last link; and a plurality of intermediate links, coupled together by the flexures such that the plurality of intermediate links, the first link, and the last link form a chain of links having the base link at a first end of the chain and the last link at a second end of the chain and each of the plurality of intermediate links is coupled to two other ones of the plurality of links by two flexures. The cable(s) extend through cable pass-through-holes in the links. The links may comprise disks with sloped faces, and may be rotational offset from another around a longitudinal axis. The flexures may comprise living hinges.