Coordinate Positioning Leg Constraint for Gravity-Stable Encoder Scales
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-Cartesian coordinate positioning machines face challenges in maintaining measurement accuracy due to gravitational-induced bending of encoder scales affixed to extendable legs, leading to distortion and errors in length measurement.
Innovation Solution
A constraint member is used to maintain the encoder scale in a substantially vertical plane relative to gravity, preventing unwanted rotation and bending, thus ensuring consistent orientation and reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the encoder scale is affixed to the extendable leg, then the length measurement can be obtained, but the encoder scale bends due to gravity causing measurement errors
Solution Approach 1:
A constraint member is introduced as an intermediary element between the encoder scale and the extendable leg. This constraint member prevents the encoder scale from bending under gravity while still allowing the leg to extend and retract, thus eliminating measurement errors caused by gravitational deformation.
Solution Approach 2:
The constraint member changes the physical state of the encoder scale from a flexible, gravity-affected component to a rigid, gravity-resistant structure. By modifying the structural parameters of the encoder scale assembly, the system eliminates gravitational bending while maintaining measurement functionality.
2Measurement precision
If the encoder scale is kept vertical to prevent bending, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The constraint function is extracted from the main extendable leg structure and implemented as a separate, dedicated constraint member. This separation allows the encoder scale to be independently constrained without complicating the overall leg mechanism, as the constraint member can be designed as a simple auxiliary component.
Solution Approach 2:
Instead of trying to make the extendable leg itself resistant to bending (which would complicate the main structure), the solution inverts the approach by adding a separate constraint element that provides the necessary rigidity. This inversion simplifies the design by keeping the main leg structure unchanged and adding only the minimal necessary constraint component.
Data Source
AI summary
A non-Cartesian coordinate positioning machine is provided that comprises an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine, and a constraint member associated with the extendable leg assembly for providing a predetermined part of the extendable leg assembly with substantially a same orientation relative to gravity for a same position of the component within the working volume. In a preferred embodiment, the orientation relative to gravity is maintained substantially constant, so that a plane defined by the predetermined part is substantially aligned with gravity, as the component is moved around the working volume.