Coordinate Measuring Machine Active Damping for Vibration Errors
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Solution Overview
Problem
Coordinate measuring machines face challenges in accurately compensating for dynamic errors caused by vibrations and oscillations, which affect measurement precision due to the movement of machine parts and external influences, especially in lighter constructions designed for faster positioning.
Innovation Solution
A method using a dynamic state model and state-space controller to manage natural frequencies and reject environmental disturbances by actively damping oscillations, with a Kalman filter and observers to estimate and control the machine's state variables, ensuring precise movement and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frame structure is made of stone (granite) to achieve high static stiffness and good damping properties, then measurement precision is improved, but the machine weight increases significantly requiring high forces for acceleration
Solution Approach 1:
The patent changes the material parameter from traditional granite to composite materials (carbon fiber reinforced plastics, glass fiber reinforced plastics). This material substitution maintains or improves static stiffness and damping properties while significantly reducing the weight of the frame structure and movable components, thereby resolving the contradiction between measurement precision and machine weight.
2Productivity
If the frame structure is made lighter to enable faster positioning, then productivity is improved, but dynamic errors from vibrations and oscillations increase affecting measurement precision
Solution Approach 1:
The patent modifies the dynamic parameters of the frame structure through material substitution and structural optimization. The composite materials and optimized geometry provide favorable dynamic characteristics including reduced natural frequencies and improved damping ratios, allowing faster positioning while maintaining measurement precision by controlling vibrations and oscillations.
Solution Approach 2:
The patent applies dynamic error compensation through active control systems that measure and compensate for dynamic deflections in real-time. This includes using sensors to detect vibrations and oscillations, then applying compensation algorithms to correct measurement values, thereby maintaining precision during high-speed positioning operations.
3Productivity
If high accelerations are applied to move frame components quickly, then productivity is improved, but dynamic deflections and vibrations increase causing measurement errors
Solution Approach 1:
The patent implements dynamic error compensation systems that actively measure and correct for dynamic deflections caused by high accelerations. This includes using acceleration sensors to detect dynamic movements, calculating compensation values based on the measured accelerations and machine dynamics model, and applying these corrections to the measurement results, thereby maintaining positioning accuracy during high-speed operations.
Solution Approach 2:
The patent employs feedback control mechanisms where sensors continuously monitor the actual position and dynamic state of frame components during movement. The measured data is fed back to the control system which adjusts the driving forces or applies post-processing corrections to compensate for dynamic errors, ensuring positioning accuracy is maintained even during high-acceleration movements.
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
This approach effectively reduces measurement uncertainties by directly managing resonances and damping vibrations, improving the accuracy of coordinate measurements by actively controlling the machine's state and movement, even at higher frequencies relevant for precision.
Implementation Method 1
providing a dynamic state information for at least one of the two structural components by means of a dynamic model with a set of model state variables... and providing a determination of an actual state of at least one of the two structural components. The dynamic model may be based on a Kalman filter and/or implemented using respective observers.
Implementation Method 2
A method using a dynamic state model and state-space controller to manage natural frequencies and reject environmental disturbances by actively damping oscillations
Data Source
AI summary
Method for providing avoiding of excitations of oscillations of a measuring machine and/or for reducing or damping such oscillations by actively controlling a driving unit of the measuring machine or actively controlling an actuation of an additionally attached actuator. The method using information about an actual state of the measuring device, the actual state is derived based on a dynamic model and/or by use of a suitable sensor unit. A state controller, an actuator or a frequency-filtering element are used for counteracting or preventing oscillations.