Numerical Controller Acceleration Time Constant Calculation
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Solution Overview
Problem
The existing numerical controllers for punch press machines face difficulties in setting table axis operations due to complex settings of boundary values, acceleration, and deceleration time constants, leading to increased overshoot and instability in press timing, especially when using the 'positioning with optimum acceleration' function.
Innovation Solution
A numerical controller that automatically calculates linear and bell-shaped acceleration and deceleration time constants based on the table axis speed and movement amount, reducing the number of operator inputs and stabilizing control by setting parameters such as reference pitch, target hit rate, and motor characteristics, thereby simplifying the setting process and minimizing overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If positioning with optimum acceleration function is used to achieve target hit rate, then press speed is improved, but setting complexity increases due to multiple boundary values and parameters
Solution Approach 1:
The control device automatically calculates and determines the acceleration and deceleration time constants based on motor characteristics and load inertia, eliminating the need for manual setting of multiple boundary values and parameters. The system serves itself by computing optimal control parameters from basic machine specifications.
Solution Approach 2:
The invention extracts the essential parameters (motor characteristics and load inertia) from the complex set of boundary values and control parameters, using only these fundamental properties to determine the acceleration and deceleration time constants, thereby simplifying the setting process.
2Speed
If acceleration and deceleration time constant is calculated from maximum motor torque, then response speed is improved, but control stability deteriorates due to overshoot
Solution Approach 1:
The invention changes the parameter used for calculating time constants from maximum motor torque to a balanced consideration of motor characteristics and load inertia. This parameter change results in time constants that provide both fast response and stable control without overshoot.
Solution Approach 2:
The control device uses feedback from the actual system characteristics (motor and load) to automatically adjust the acceleration and deceleration time constants, ensuring optimal performance without manual tuning or risk of overshoot.
3Measurement precision
If boundary value switching is used for table axis acceleration, then positioning precision is improved, but operation stability deteriorates due to significant changes with slight movement differences
Solution Approach 1:
The invention transitions from static boundary value switching to dynamic time constant adjustment. The acceleration and deceleration time constants are continuously optimized based on actual motor characteristics and load conditions, providing smooth and stable control without abrupt changes.
Solution Approach 2:
The control device performs preliminary calculation of the acceleration and deceleration time constants based on machine specifications before operation begins. This preliminary action ensures stable and predictable control behavior throughout the operation without requiring real-time adjustments or boundary value switching.
Data Source
AI summary
A numerical controller of the present invention includes a parameter setting unit which accepts settings of punch press parameters, an NC parameter calculating unit which calculates an axis control parameter in punch pressing based on the punch press parameters, a parameter storage unit which stores the punch press parameters and the axis control parameter, a command analyzing unit which analyzes a command block in the program to generate movement command data, an interpolating unit which generates interpolation data based on the movement command data, and an accelerating and decelerating unit which calculates a linear acceleration and deceleration time constant and a bell-shaped acceleration and deceleration time constant for use in axis control based on the punch press parameters, the axis control parameter, and a feed rate specified by the command block and performs post-interpolation acceleration or deceleration processing based on each of the calculated acceleration and deceleration time constants.