Dynamic Model Updating for CMM Vibration Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current coordinate measuring machines (CMMs) face challenges in accurately compensating for dynamic errors and vibrations, which affect measurement precision due to their weight and stiffness, and existing models fail to handle these errors continuously with high precision, especially in weight-reduced designs.
Innovation Solution
A dynamic model with state variables related to physical properties of the CMM is defined and updated to continuously calculate the machine's state, allowing for the monitoring and compensation of vibrations and deformations, thereby improving measurement accuracy and reducing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frame structure is made of stone (granite) to achieve high static stiffness, then measurement precision is improved, but the machine weight increases and requires high forces for acceleration
Solution Approach 1:
The patent changes the material parameter from traditional granite to carbon fiber reinforced plastic (CFRP), which has fundamentally different mechanical properties - specifically, it achieves comparable or superior stiffness with dramatically reduced weight. This material substitution resolves the contradiction by providing an alternative that delivers the required measurement precision without the penalty of high machine weight.
2Measurement precision
If the frame structure is made of stone (granite) to achieve high static stiffness, then measurement precision is improved, but dynamic errors such as resonances and vibrations increase
Solution Approach 1:
The patent changes the material parameter from granite to CFRP, which alters the dynamic characteristics of the machine. CFRP provides different damping properties and natural frequencies that reduce resonances and vibrations during operation, thereby decreasing dynamic errors while maintaining measurement precision.
Solution Approach 2:
The patent replaces the traditional mechanical granite frame with a CFRP composite structure, fundamentally changing the mechanical system's properties. This substitution introduces materials with superior damping characteristics and different stiffness-to-weight ratios, which actively reduce dynamic errors like resonances and vibrations that plague traditional granite-based CMMs.
3Productivity
If weight reduction is implemented in CMM parts, then productivity is improved through faster positioning, but measurement accuracy decreases due to increased vibrations and torsions
Solution Approach 1:
The patent changes the material parameter to CFRP, which has a fundamentally different strength-to-weight ratio and damping characteristics compared to traditional materials. This enables weight reduction for faster positioning while simultaneously providing inherent vibration damping that maintains measurement accuracy, thus resolving the contradiction between productivity and precision.
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~4d
AI summary
The invention relates to a method for providing dynamic state information for at least a part of a coordinate measuring machine, the coordinate measuring machine comprising a base, a probe head, a machine structure with structural components for linking the probe head to the base and at least one drive mechanism for providing movability of the probe head relative to the base. Furthermore, a dynamic model with a first set of state variables is defined for representing an actual state of at least the part of the coordinate measuring machine, wherein the set of state variables represents a set of physical properties of at least the part of the coordinate measuring machine. The first set of state variables is provided in a database and the actual state of at least the part of the coordinate measuring machine is determined by a calculation based on the dynamic model. According to the invention, a monitoring of the state variables and, based thereon, determining a change of at least one of the state variables, are performed, wherein a second set of state variables is set with updated state variables as to the determined change of the at least one of the state variables. Additionally, the dynamic model is updated using the second set of state variables as the first set of state variables, in particular wherein the actual state of at least the part of the coordinate measuring machine is calculated based on at least the second set of state variables.