Multi-Axis Numerical Control for Reciprocating End-Point Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-axis synchronization control systems, the child axis often fails to reach the end point due to servo delays during reciprocating motions, leading to shock when feedforward control is activated, and existing methods require trial-and-error corrections, resulting in non-uniform band shapes in applications like non-woven fabric wrapping.
Innovation Solution
A numerical controller with an end-point correction unit that calculates and adds an additional movement amount to the child axis to reach the end point and adjusts the synchronization ratio, and subsequently corrects the parent axis movement to recover synchronization, allowing for precise control without trial-and-error adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feedforward control is activated during reciprocating motion to overcome servo delay, then the child axis can reach the end point, but too much shock is caused making activation unrealistic
Solution Approach 1:
The system performs preliminary correction by adding an additional movement amount to the child axis command before the reciprocating motion begins. This preliminary action compensates for the servo delay in advance, allowing the child axis to reach the end point without requiring aggressive feedforward control during motion, thereby avoiding excessive shock.
Solution Approach 2:
The system changes the movement amount parameter by calculating and adding an additional movement amount (Δc) based on the servo delay characteristics. This parameter adjustment compensates for the servo delay effect, enabling precise end point reachability while maintaining normal acceleration and deceleration profiles that avoid excessive shock.
2Manufacturing precision
If trial and error correction is used to calculate movement operation, then correction amount can be determined, but movement operation must be repeated and appropriate correction is not performed initially
Solution Approach 1:
The system uses feedback from the actual reciprocating motion to calculate the additional movement amount. By measuring the deviation from the expected end point and using this feedback information, the system determines the precise correction amount needed, eliminating the need for repetitive trial and error operations.
Solution Approach 2:
The correction amount calculated from feedback is applied as a preliminary adjustment to the child axis command in subsequent operations. This preliminary application of correction based on learned feedback eliminates the need for repeated trial and error movements, achieving accurate positioning from the start of corrected operations.
3Manufacturing precision
If correction is applied to the child axis to reach end point, then positioning accuracy improves, but synchronization between parent and child axes is destroyed
Solution Approach 1:
The system applies local quality correction by adding the additional movement amount (Δc) only to the child axis command, while keeping the parent axis command unchanged. This localized correction achieves end point positioning accuracy for the child axis without disrupting the overall synchronization relationship between parent and child axes.
Solution Approach 2:
The synchronization ratio acts as an intermediary that coordinates the relationship between parent and child axes. By calculating the additional movement amount based on the synchronization ratio and applying it only to the child axis, the system maintains the proportional relationship between axes while achieving precise positioning.
Data Source
AI summary
A numerical controller, which reciprocates a parent axis and a child axis according to a predetermined synchronization ratio by multi-axis synchronization control, is provided with a command decoding unit configured to decode a command including a plurality of command blocks, a distribution processing unit configured to generate a distribution movement amount, which is an amount of movement for each control period of a motor, based on the command blocks, an end-point correction unit configured to perform first correction processing for correcting the distribution movement amount so that a feedback position of the child axis reaches an end point, which is a turning point of the reciprocating motion, and second correction processing for recovering synchronization destroyed by the first correction processing, and a motor control unit configured to drivingly control the motor based on the corrected distribution movement amount.