Numerical Controller Velocity Stabilization via Command Adjustment
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Solution Overview
Problem
Numerical controllers for servo motors face instability due to abrupt changes in velocity when loads are applied and then removed, causing the motor to accelerate with maximum torque and result in unstable operation.
Innovation Solution
A numerical controller that includes a commanded movement-amount adjustment section, which calculates an adjusted command movement amount based on the commanded movement amount, positional deviation, and actual velocity to prevent abrupt acceleration, ensuring the servo motor returns to a target position and velocity without sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position loop control is used to eliminate positional deviation, then positioning accuracy is improved, but velocity stability deteriorates when load is abruptly removed
Solution Approach 1:
The patent introduces a commanded movement-amount adjustment section as an intermediary between the position command section and positional deviation counter. This intermediary calculates adjusted commanded movement amounts that consider both positional deviation and actual velocity, preventing abrupt velocity changes while maintaining positioning accuracy through gradual correction.
Solution Approach 2:
The patent dynamically adjusts the commanded movement amount based on real-time feedback of actual velocity and positional deviation. The adjustment section modifies the commanded movement amount in each distributed cycle according to the current state, creating a dynamic control system that adapts to load changes and prevents abrupt acceleration.
2Measurement precision
If maximum torque is applied to eliminate accumulated positional deviation, then positioning accuracy is improved, but velocity stability deteriorates
Solution Approach 1:
The patent applies periodic adjustment of the commanded movement amount in distributed cycles rather than applying maximum torque immediately. The adjustment section continuously calculates and applies small corrections over multiple cycles, gradually eliminating positional deviation while maintaining smooth velocity transitions.
Solution Approach 2:
The patent cushions against abrupt velocity changes by pre-calculating adjusted commanded movement amounts that consider the current actual velocity. The adjustment section prepares moderate correction values in advance rather than allowing maximum torque to be applied suddenly, preventing velocity instability.
3Measurement precision
If commanded movement amount is increased to reduce positional deviation, then positioning accuracy is improved, but velocity control precision deteriorates
Solution Approach 1:
The patent uses feedback from the actual velocity detection section to continuously monitor the velocity state. The commanded movement-amount adjustment section uses this feedback to calculate appropriate adjusted commanded movement amounts, ensuring that positioning correction does not cause velocity deviations beyond acceptable limits.
Data Source
AI summary
A numerical controller includes a commanded movement-amount adjustment section, in addition to a position command section and a positional deviation counter but also. The commanded movement-amount adjustment section calculates an adjusted command movement amount based on a commanded movement amount output from the position command section, positional deviation acquired from the positional deviation counter, and an actual velocity of a control axis, and outputs the calculated adjusted command movement amount to the positional deviation counter. When a load acts on a servo motor so that positional deviation is accumulated and the load is abruptly removed, a situation in which the servo motor abruptly accelerates with its maximum torque in an attempt to eliminate the accumulated positional deviation is avoided.