Motor Controller Diagnostic Mode for Abnormality Detection
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Solution Overview
Problem
Existing methods for detecting motor abnormalities in industrial machines, such as those used in machine tools or robots, often fail to detect impending issues due to minimal sensor usage, as properly controlled motors do not exhibit significant speed or position differences when abnormalities occur, making it difficult to detect errors in cycle time.
Innovation Solution
A controller with a detector for speed or position feedback values that switches between normal and diagnostic operation modes, altering motor control systems to increase sensitivity to disturbances, allowing for abnormality detection without additional sensors by changing gain settings, inserting filters, and stopping control outputs at predetermined moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If motor control parameters are optimized for normal operation to maintain stable motor performance, then motor control stability is improved, but sensitivity to detect abnormalities decreases
Solution Approach 1:
The patent applies dynamics by making the motor control parameters changeable between two distinct modes: a first control parameter set for normal operation that ensures stability, and a second control parameter set for diagnostic operation that enhances abnormality detection sensitivity. The controller dynamically switches between these parameter sets based on the operational phase, allowing the system to adapt its characteristics to meet different functional requirements.
Solution Approach 2:
The patent directly implements parameter changes by modifying motor control parameters (such as gain values in PID control) when transitioning from normal operation to diagnostic operation. During diagnostic mode, parameters are adjusted to amplify the relationship between motor abnormalities and observable output changes, enabling more sensitive detection while maintaining stable control during normal operation.
2Measurement precision
If additional sensors are installed to improve abnormality detection capability, then detection accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent applies self-service by enabling the motor control system to perform its own abnormality detection function. By switching to diagnostic control parameters, the existing motor control infrastructure (sensors, controllers, and actuators) is utilized to detect abnormalities without requiring external diagnostic equipment or additional sensors. The system essentially diagnoses itself by observing how it responds to controlled parameter changes.
Solution Approach 2:
The patent implements multi-functionality by designing the motor control system to serve dual purposes: normal operation control and abnormality detection. The same control parameters and existing sensors are used for both motor control and diagnostic functions, eliminating the need for separate detection hardware and reducing overall system complexity while maintaining detection accuracy.
3Measurement precision
If motor control parameters are adjusted to increase response to disturbances for better abnormality detection, then abnormality detection sensitivity is improved, but normal operation stability deteriorates
Solution Approach 1:
The patent resolves this contradiction through dynamic parameter switching. During normal operation, the first control parameters are used to maintain stable motor performance. When diagnostic operation is initiated, the controller dynamically switches to the second control parameters that are specifically tuned to amplify abnormality signals. This temporal separation allows each parameter set to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent applies segmentation by dividing the operational timeline into distinct phases: normal operation phase and diagnostic operation phase. Each phase has its own optimized control parameters. The abnormality detection process is segmented as a separate operational mode rather than being continuously applied, allowing the system to maintain stability during normal operation while achieving high detection sensitivity during dedicated diagnostic intervals.
Data Source
AI summary
A controller can switch a control system of a motor to a diagnostic operation mode in addition to a normal operation mode. Abnormality of the motor can be detected by taking advantage of the appearance of a clear difference between a feedback value detected when the motor is normal and a feedback value detected when the motor is abnormal if the control system is switched to the diagnostic mode.