Electric Motor Control for Automatic Inertia Estimation
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Solution Overview
Problem
In machine tools, the inertia estimation function is typically activated manually by operators, which is inefficient and time-consuming, as it requires stable operations and accurate knowledge of the driven body's inertia.
Innovation Solution
A controller for electric motors that includes a first inertia estimating unit to determine if the inertia of the driven body has changed based on operation program information, detection device data, or motor operation state, and a second unit to estimate inertia when changes are detected, allowing for automatic activation of the inertia estimation function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inertia estimation function is activated manually by operators, then the estimation can be performed with stable operations, but the operational efficiency is reduced and time is consumed
Solution Approach 1:
The controller automatically determines whether to activate the inertia estimation function by itself, using its own detected information about the driven body and operation conditions, eliminating the need for manual operator intervention while maintaining reliable estimation
Solution Approach 2:
The controller uses feedback from detection devices that monitor the shape and characteristics of the driven body to automatically trigger inertia estimation when changes are detected, ensuring reliable estimation is performed only when necessary
2Productivity
If the inertia estimation function is activated automatically based on detected changes, then the operational efficiency is improved, but the complexity of the control system increases
Solution Approach 1:
The controller integrates multiple functions into a single device: it detects the shape of the driven body, determines whether inertia has changed, and activates the inertia estimation function, eliminating the need for separate dedicated devices and reducing overall system complexity
Solution Approach 2:
The control system is divided into distinct functional modules: a detection device for monitoring driven body characteristics, a determination unit for assessing inertia changes, and an estimation unit for calculating inertia, allowing each module to be optimized independently while maintaining overall system efficiency
3Measurement precision
If the inertia estimation is performed frequently to ensure accuracy, then the measurement precision is improved, but the time consumption increases
Solution Approach 1:
The inertia estimation function is activated periodically based on detected changes in the driven body's characteristics rather than continuously or manually, ensuring accurate measurement is performed at appropriate intervals without unnecessary time consumption
Solution Approach 2:
The detection device continuously monitors the shape and characteristics of the driven body in advance, so when a change is detected, the inertia estimation function can be activated immediately with accurate data already available, eliminating the need for time-consuming manual assessment
Data Source
AI summary
Provided is a control device capable of automatically determining whether or not an inertia estimation function needs to be activated. The control device 10 is for an electric motor and comprises: a first inertia estimation unit 11 that estimates whether or not there has been a change in the inertia of an object to be driven, on the basis of at least one among first information pertaining to an operation program or operation settings for a device comprising the electric motor, second information obtained from a detection device for detecting the shape of the object to be driven by the electric motor, and third information indicating the operation state of the electric motor; and a second inertia estimation unit 12 that estimates the inertia of the object to be driven if the first inertia estimation unit 11 has estimated that there has been a change in the inertia of the object to be driven.