Collision Prevention in Numerical Control Apparatus
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Solution Overview
Problem
Conventional collision preventing devices in numerical control apparatuses fail to accurately prevent collisions as they do not account for the deviation of the actual moving path from the commanded path, leading to potential interference despite initial detection of no interference along the commanded path.
Innovation Solution
A collision preventing device that includes an acceleration/deceleration simulating unit to generate a moving path, an interference check unit to verify potential interference along this path, and a moving command blocking unit to inhibit the function generation if interference is detected, ensuring accurate collision prevention by considering the deviation of the actual moving path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference checking is performed only on the commanded path, then the checking process is simple and fast, but the actual collision prevention accuracy deteriorates because the actual moving path may deviate from the commanded path
Solution Approach 1:
The patent performs preliminary interference checking on the commanded path before actual machining, and then performs secondary interference checking on the simulated actual moving path. This preliminary action allows the system to identify potential collision risks before they occur, while the simulation step accounts for actual path deviations caused by acceleration/deceleration processing.
Solution Approach 2:
The patent creates a virtual copy of the actual moving path through simulation of acceleration/deceleration processing on the commanded path. This copied simulated path is then used for interference checking, allowing the system to verify collision-free operation on the actual trajectory without physically executing the machining operation first.
2Object-affected harmful factors
If acceleration/deceleration processing is applied to each axis, then the impact on workpiece is reduced, but the actual moving path deviates from the commanded path, causing potential interference
Solution Approach 1:
The patent simulates the acceleration/deceleration processing on the commanded path to generate a copied actual moving path. This simulation copying allows the system to predict the true trajectory the tool will follow during machining, accounting for the path deviations caused by acceleration/deceleration while maintaining the benefits of smooth motion control.
Solution Approach 2:
The system performs preliminary simulation of acceleration/deceleration effects on the commanded path before actual machining. This preliminary action reveals the actual moving path and allows interference checking to be performed on this simulated trajectory, ensuring collision prevention reliability while maintaining smooth acceleration/deceleration processing.
3Measurement precision
If interference checking is performed on the simulated actual moving path, then collision detection accuracy is improved, but the processing time increases
Solution Approach 1:
The patent performs interference checking on the simulated actual moving path as a preliminary verification step before actual machining. By simulating the acceleration/deceleration processing and checking the resulting path in advance, the system ensures high collision detection accuracy while the computational overhead is incurred during the programming/setup phase rather than during production machining.
Data Source
AI summary
A collision preventing device includes an acceleration/deceleration simulating unit 30 that performs acceleration/deceleration processing based on a moving command generated by a function generation unit 16 according to a method similar to that used by acceleration/deceleration units 18x and 18z and obtains a moving path resulting from the acceleration/deceleration processing, an interference check unit 34 that performs interference check between a mobile member and an interfering object along the moving path generated by the acceleration/deceleration simulating unit 30 and determines whether any interference may occur, a delay unit 32 that successively stores moving commands generated by the function generation unit 16 and successively outputs a moving command having been stored a predetermined time before, and a moving command blocking unit 36 that sends the moving command output from the delay unit 32 to the acceleration/deceleration units 18x and 18z if the interference check unit 34 determines that there is no interference, and blocks the moving command to be sent from the delay unit 32 to the acceleration/deceleration units 18x and 18z if the interference check unit 34 determines that interference may occur.