Numerical Control Unit Interference Prevention via Safe Distance Calculation
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Solution Overview
Problem
Conventional numerical control units for machine tools face challenges in accurately preventing collisions during manual axial movement operations, as they rely on pre-defined safe ranges and lack precise methods to decelerate and stop at desired positions, especially when interfering objects are involved.
Innovation Solution
A numerical control device with an operation input device, memory for shape data, interference check section, and function generator that calculates a stop position separated from an interference position to prevent collisions, allowing for safe movement and deceleration in machine tools, even during two-axis or multi-axis operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stop command is issued unidirectionally towards the numerical control unit when interference is detected, then interference prevention is achieved, but axial movement cannot be accurately decelerated and stopped at the desired position
Solution Approach 1:
The patent implements bidirectional communication between the interference prediction device and numerical control unit. The NC unit sends axial movement instructions to the prediction device, which returns interference determination results. This feedback loop enables the NC unit to receive real-time interference information and generate appropriate control functions to decelerate and stop the moving section at precise positions before interference occurs.
Solution Approach 2:
The interference prediction device performs interference determination in advance based on predicted axial positions before actual movement occurs. By calculating potential interference positions beforehand and communicating them to the NC unit, the system can proactively adjust movement commands to prevent interference while maintaining accurate stopping at desired positions.
2Reliability
If the moving section moves very finely to confirm whether or not there is interference, then interference avoidance is achieved, but movement efficiency is significantly reduced
Solution Approach 1:
The patent replaces the mechanical trial-and-error movement approach with an information-based interference prediction system. Instead of moving the physical moving section incrementally to test for interference, the system uses shape data of the moving section and interfering objects to computationally predict interference positions, enabling continuous efficient movement while maintaining safety.
Solution Approach 2:
The system creates virtual models (shape data) of the moving section and interfering objects to simulate and predict interference scenarios. By working with these digital copies rather than physical movements, the system can evaluate multiple potential paths and positions rapidly without actual mechanical movement, maintaining productivity while ensuring safety.
3Ease of operation
If a pre-defined safe range is used for each control axis, then collision prevention is simplified, but interference with objects within the safe range cannot be avoided
Solution Approach 1:
The patent applies different levels of safety control to different spatial regions. Within pre-defined safe ranges, normal movement operations are permitted with standard control. When the moving section approaches boundaries defined by interfering objects (determined through shape data comparison), localized interference prediction activates to provide additional safety checks, allowing efficient operation in safe zones while maintaining protection near potential hazard zones.
Data Source
AI summary
When causing manual movement of a moving section of a machine tool, shape data of the moving section is made to move in a movement direction that has been input manually, and it is confirmed whether there is no interference with shape data of a surrounding interfering object. If interference occurs, a position returned a specified distance from the position where interference occurs is made a stop position, the moving section is moved to this stop position, and stopped at that position.