Numerical Control Device Smooth Deceleration Override
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Solution Overview
Problem
Existing numerical control devices face challenges in smoothly decelerating and stopping during high-speed cycle machining without increasing the workload for generating high-speed cycle machining data or ladder programs, and require long times for restarting operations due to synchronization issues between the grindstone and workpiece.
Innovation Solution
A numerical control device with an override input unit, decelerating and stopping override change unit, and velocity calculation unit that calculates actual override at each interpolation period to smoothly decelerate and stop the machining tool, reducing the need for large high-speed cycle machining data and decreasing restart time by changing the actual override stepwisely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the machine stops immediately at interruption of high-speed cycle machining, then the control is simple, but mechanical shock and machining error occur
Solution Approach 1:
The patent applies dynamics by making the deceleration process adaptive and dynamic. The feed rate is automatically adjusted based on the distance to the target position and current machining state, transitioning from constant high-speed cycling to controlled deceleration. This dynamic adjustment eliminates mechanical shock while maintaining control simplicity through automated calculation of deceleration parameters.
Solution Approach 2:
The patent changes the feed rate parameter dynamically during the deceleration process. By modifying the feed rate from the original high-speed cycle value to a decelerated value based on calculated parameters (distance, current feed rate, deceleration rate), the system achieves smooth stopping without mechanical shock while preventing machining errors that would occur with immediate stopping.
2Reliability
If high-speed cycle machining data for decelerating and stopping is prepared, then the machine can stop smoothly, but data size and work load for generation increase
Solution Approach 1:
The system applies self-service by automatically calculating and generating the deceleration control parameters during operation. Instead of requiring pre-prepared deceleration data tables that would increase data size, the control device computes the necessary feed rate adjustments in real-time based on current position, distance to target, and machining parameters, thereby achieving smooth stopping without increasing data storage requirements.
Solution Approach 2:
The patent makes the deceleration control dynamic by calculating feed rate adjustments on-the-fly during operation rather than using static pre-programmed deceleration data. This dynamic approach allows the system to adapt to varying machining conditions while avoiding the need to store large amounts of deceleration data for different scenarios.
3Reliability
If the override is decreased little by little using ladder program, then the machine can stop smoothly, but the time and distance necessary for deceleration become long
Solution Approach 1:
The patent applies periodic action by implementing deceleration at fixed interpolation intervals rather than continuously or in large steps. The feed rate is adjusted at each interpolation cycle based on the remaining distance and current state, creating a series of small, periodic adjustments that achieve smooth deceleration efficiently. This periodic adjustment method balances smoothness with time efficiency.
Solution Approach 2:
The system uses dynamic feed rate adjustment where the deceleration rate is adapted based on real-time conditions. Rather than using a fixed gradual override reduction, the control device calculates optimal deceleration parameters dynamically, adjusting the feed rate reduction amount based on distance to target, current speed, and machining state, thereby achieving smooth stopping in minimal time.
4Device complexity
If the machine stops immediately during high-speed cycle machining, then the control is simple, but restart time is long due to synchronization requirements
Solution Approach 1:
The patent applies preliminary action by performing controlled deceleration to a predetermined position before stopping, rather than immediate stopping. This preliminary deceleration phase prepares the system for a smoother, faster restart by ensuring the machine is already moving at reduced speed and positioned appropriately, thereby reducing the time required to resume synchronous operation after interruption.
Data Source
AI summary
A numerical control device configured to perform stopping control of an axis of a machining tool to be controlled corresponding to command for machining interruption during machining by moving a workpiece or a tool using cycle operation, the numerical control device includes an override input unit, a decelerating and stopping override change unit configured to calculate actual override, decelerated in stages at each interpolation period based on the override acquired by the override input unit, and a velocity calculation unit configured to decelerating and stopping control of the axis.