Numerical Control Apparatus Emergency Stop Coordinate Restoration
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Solution Overview
Problem
In NC turret lathes without a Y axis, emergency stops complicate the return to the previous state due to cancellation of imaginary Y-axis control, making it difficult to synchronize turret and work movements, leading to potential tool breakage and loss of coordinate precision.
Innovation Solution
A numerical control apparatus that includes an imaginary-Y-axis control unit, an acquiring unit, and a restoring unit to convert X-Y axes movement commands, acquire current positions during an emergency stop, and restore program coordinate positions, enabling the machine tool to return to its previous state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If imaginary Y-axis control is cancelled during emergency stop, then the machine tool can be stopped safely, but it becomes difficult to return the turret and work to synchronized positions
Solution Approach 1:
The control unit stores the coordinate values of the turret and work immediately before emergency stop occurs. This preliminary recording of position data enables the system to restore the synchronized state after emergency stop by replaying the stored coordinates, avoiding the need to manually re-synchronize the turret and work.
Solution Approach 2:
The system continuously monitors the positions of the turret (X-H axes) and work (C axis) during imaginary Y-axis control, and uses this feedback information to calculate and restore the correct synchronized positions after emergency stop. The control unit compares current positions with stored pre-emergency positions to determine restoration commands.
2Reliability
If the machine tool is emergency-stopped with tool inserted into work, then processing can be halted, but the tool may break when attempting to pull out
Solution Approach 1:
The control unit records the precise coordinate positions of the turret and work before emergency stop. After emergency stop release, the system restores these positions to ensure the tool is properly aligned with the work, preventing forced extraction that could cause tool breakage.
Solution Approach 2:
The control unit acts as an intermediary that coordinates the movement of turret and work independently after emergency stop. By controlling each axis separately based on stored coordinates, the system ensures smooth tool extraction without mechanical conflict or excessive force.
3Productivity
If turret and work move with own weights after emergency stop release, then servo-off state is achieved, but coordinate positions cannot be grasped
Solution Approach 1:
The control unit stores the coordinate values of all axes (X, H, C) immediately before emergency stop. This preliminary recording preserves the positional information even when servo motors are turned off and components move under gravity, enabling accurate restoration of the machining state.
Solution Approach 2:
The system creates a digital copy of the position data from the physical axis positions before emergency stop. This copied information is stored and used to restore the exact machining state after emergency stop, eliminating the need to physically reposition components and ensuring coordinate accuracy.
4Adaptability or versatility
If imaginary Y-axis control is used to enable machining without Y axis, then machine tool versatility is improved, but control complexity increases
Solution Approach 1:
The control unit serves as an intermediary that translates imaginary Y-axis movement commands into coordinated movements of the actual X, H, and C axes. This mediation layer maintains the simple programming interface of imaginary Y-axis control while managing the complexity of multi-axis coordination internally.
Solution Approach 2:
The system changes the control parameters by converting Y-axis coordinate commands into combinations of X, H, and C axis movements. This parameter transformation enables the machine to perform Y-axis equivalent operations using available axes, maintaining versatility without requiring additional hardware.
Data Source
AI summary
A numerical control apparatus includes an imaginary-Y-axis control unit configured to execute an imaginary Y-axis control mode which is a mode for converting an X-Y axes movement command in a machining program described in a program coordinate system into a command in a machine coordinate system including X-H-C axes and for driving the X axis, the H axis, and the C axis in association with one another according to the converted command, an acquiring unit configured to acquire, when an emergency stop occurs during the imaginary Y-axis control mode, present positions of the X axis, the C axis, and the H axis at the time when the emergency stop is released, and a restoring unit configured to restore a present X-axis coordinate position and a present Y-axis coordinate position in the program coordinate system from the acquired present positions of the X axis, the C axis, and the H axis.