Numerical Control Device Speed Difference Cause Analysis
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Solution Overview
Problem
Existing numerical control devices struggle to identify the specific cause of differences between commanded and actual motor speeds, especially when multiple speed compensation functions are active or when parameter settings are inadequate, leading to difficulties in troubleshooting issues like stalled feed shafts or non-turning spindles during automatic operations.
Innovation Solution
A numerical control device equipped with a command speed calculating unit, speed/acceleration control unit, motor control unit, data storage unit, difference pattern table, cause analyzing unit, and display unit, which calculates and compares command and actual speeds, and their intermediate compensated values to determine the cause of speed differences, allowing operators to visualize changes through graphical displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple speed compensation functions are activated to control motor speed, then the motor speed control capability is improved, but it becomes impossible to specify which function influences the actual speed to what extent
Solution Approach 1:
The patent segments the speed compensation process by calculating and storing intermediate compensated speeds for each individual speed compensation function in sequence. This allows the system to divide the overall speed control into distinct stages, each associated with a specific compensation function, enabling traceability of which function causes which speed change.
Solution Approach 2:
The patent introduces intermediate compensated speeds as intermediary values between the command speed and the final actual speed. Each intermediate speed represents the result after applying a specific compensation function, serving as a mediator that links the command speed to the final actual speed while preserving information about which function caused which change.
2Measurement precision
If the system stores and compares command speed and actual speed data, then the ability to diagnose speed differences is improved, but the complexity of data processing and analysis increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing intermediate compensated speeds for each compensation function in chronological order before final analysis. This preparation work is done in advance, organizing the data structure so that cause analysis can be performed by simple comparison without complex real-time processing.
Solution Approach 2:
The patent implements feedback by comparing the stored intermediate compensated speeds with the actual speed and displaying the results to the operator. This feedback loop provides information about which compensation function is causing speed differences, enabling operators to adjust parameters or switch functions to resolve issues.
3Ease of operation
If the system displays detailed speed compensation information to help operators diagnose issues, then the ease of operation is improved, but the information processing load increases
Solution Approach 1:
The patent extracts only the essential diagnostic information needed for troubleshooting by displaying which specific compensation function is causing the speed difference and by how much. Instead of showing all raw data, it extracts and presents the relevant cause information, reducing the effective information volume while maintaining diagnostic capability.
Data Source
AI summary
A numerical control device includes: a data storage unit that cyclically associates and stores command speeds and actual speeds of a motor in chronological order; a difference pattern table that associates and stores causes of a difference between the command speed and the actual speed, and difference patterns of the causes; a cause analyzing unit that analyzes the cause of the difference between the command speed and the actual speed by comparing the command speeds and the actual speeds stored in chronological order in the data storage unit, with the difference patterns stored in the difference pattern table; and a display unit that displays the analyzed cause.