Geometric Error Identification Using Circular Arc Approximation
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Solution Overview
Problem
Current methods for identifying geometric errors in five-axis machines can only partially identify errors, either requiring expensive equipment for rotational axes or being limited to identifying errors in rotational axes, failing to simultaneously and accurately identify errors in both translational and rotational axes, especially under conditions of thermal displacement and secular changes.
Innovation Solution
A method using a control device with a position measurement sensor to measure jig positions in three-dimensional space, approximating these measurements to a circular arc, and calculating center position and tilt errors for both rotational and translational axes, allowing for simultaneous identification of geometric errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to identify geometric errors in rotational axes, then measurement precision is improved, but device complexity and cost increase due to requiring expensive specialized equipment
Solution Approach 1:
The touch trigger probe is designed to perform multiple functions: it can measure both rotational axis geometric errors and translational axis geometric errors using the same device. The probe serves as a universal measurement tool that eliminates the need for specialized expensive equipment by integrating capability to detect various types of geometric errors through different measurement procedures
Solution Approach 2:
The invention replaces complex mechanical measurement systems with an electrical/electronic sensing system. The touch trigger probe uses electrical signals and digital processing to detect geometric errors, substituting traditional mechanical measurement devices with modern sensor-based systems that are more versatile and cost-effective
2Measurement precision
If conventional methods are used to identify geometric errors, then measurement precision for rotational axes is improved, but completeness of error identification worsens due to inability to simultaneously identify errors in both rotational and translational axes
Solution Approach 1:
The measurement procedure merges the identification of rotational axis geometric errors and translational axis geometric errors into a single integrated process. By combining these measurements and using unified calculation procedures, the system achieves complete error identification without requiring separate measurement systems, thus preventing loss of information about any geometric errors
Solution Approach 2:
The touch trigger probe and measurement system are designed with universal capability to detect both rotational and translational geometric errors. This multi-functional approach ensures that no geometric error information is lost, as the same system can identify all types of errors present in the five-axis machine
3Device complexity
If affordable touch trigger probes are used, then device complexity is reduced and cost decreases, but measurement precision worsens due to potential limitations in detecting geometric errors accurately
Solution Approach 1:
The invention changes the measurement parameters and procedures to optimize the performance of the touch trigger probe. By carefully selecting measurement positions, angles, and calculation methods, the system maximizes the measurement capability of the affordable probe, achieving high precision geometric error identification despite using simpler equipment
Solution Approach 2:
The measurement system uses digital modeling and calculation to create an accurate representation of the geometric errors. By copying the physical measurement data into digital form and processing it through sophisticated algorithms, the system compensates for the simpler hardware, achieving high measurement precision through software-based error correction and calculation
Data Source
AI summary
A method for identifying geometric errors with respect to at least two translational axes and at least one rotational axis of a machine using a control device is disclosed. The method comprises the steps of: measuring positions of a jig in three-dimensional space using a position measurement sensor, wherein a measurement is carried out when the jig being indexed around the rotational axis by a plurality of angles is located at the positions; approximating a plurality of measured values of the positions measured in the measuring step to a circular arc; and calculating an error in regard to a center position of the rotational axis and/or a tilt error in the rotational axis, and tilt errors in the translational axes, based on the circular arc resulting from the approximating step.