Numerical Controller Speed Control Using Curvature Change Amounts
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Solution Overview
Problem
Conventional numerical controllers face challenges in achieving optimum speed control along curved and corner-shaped movement paths, leading to decreased machining speed and increased cycle time due to restrictive acceleration limits and difficulty in precise shape determination.
Innovation Solution
A numerical controller that uses curvature and curvature change amounts to dynamically adjust speed calculation constants, allowing for smooth speed transitions and precise control, particularly applying severe speed limitations only where necessary to enhance precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a constant value is set for speed calculation to ensure precision on severe movement paths, then manufacturing precision is improved, but productivity deteriorates due to overall speed limitation
Solution Approach 1:
The patent applies different speed calculation constants to different sections of the movement path based on local curvature characteristics. Severe speed limitations are applied only to edge shapes with high curvature change amounts, while moderately curved sections use more permissive constants, allowing higher speeds in less critical areas.
Solution Approach 2:
The patent dynamically adjusts the speed calculation constant based on the actual curvature change amount at each position along the movement path. Instead of using a fixed constant for the entire path, the system selects from multiple constants (K1, K2, K3) depending on whether the curvature change exceeds predetermined thresholds, enabling adaptive speed control.
2Productivity
If the movement speed is increased to improve productivity, then cycle time is reduced, but manufacturing precision deteriorates due to excessive acceleration on curved paths
Solution Approach 1:
The patent changes the parameter (speed calculation constant) based on the curvature change amount. By using multiple constants (K1 for high curvature change, K2 for medium, K3 for low) and selecting appropriate constants based on actual path conditions, the system optimizes the balance between speed and precision for each section of the movement path.
3Device complexity
If a single constant value is used for speed control to simplify the system, then device complexity is reduced, but manufacturing precision deteriorates due to inability to adapt to varying path shapes
Solution Approach 1:
The patent applies different speed calculation constants to different sections of the movement path based on local curvature characteristics. Severe speed limitations are applied only to edge shapes with high curvature change amounts, while moderately curved sections use more permissive constants, allowing higher speeds in less critical areas.
Solution Approach 2:
The patent dynamically adjusts the speed calculation constant based on the actual curvature change amount at each position along the movement path. Instead of using a fixed constant for the entire path, the system selects from multiple constants (K1, K2, K3) depending on whether the curvature change exceeds predetermined thresholds, enabling adaptive speed control.
4Device complexity
If corner shape determination is performed using angle calculation between blocks to simplify control, then device complexity is reduced, but manufacturing precision deteriorates due to sensitivity to instruction point density
Solution Approach 1:
The patent changes the parameter (speed calculation constant) based on the curvature change amount. By using multiple constants (K1 for high curvature change, K2 for medium, K3 for low) and selecting appropriate constants based on actual path conditions, the system optimizes the balance between speed and precision for each section of the movement path.
Data Source
AI summary
A numerical controller which controls a machine tool on the basis of a program instruction analyzes the program instruction to generate movement instruction data, and sets a value of a constant used for speed change on the basis of a physical amount regarding a curvature at a current position on a movement path based on the generated movement instruction data. Then, the numerical controller calculates movement speeds of axes of the machine tool using the set value of the constant used for the speed change, and controls the axes on the basis of the calculated movement speeds.