Motor-Driven Vibration Mode Determination for Machine Structures
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Solution Overview
Problem
Conventional vibration mode determining apparatuses face challenges in determining the vibration mode of machines with high reliability and accuracy due to user burden and size restrictions, particularly when using impulse hammers or vibrators for excitation, and require complex data processing for sensor orientation and transfer function recalculations.
Innovation Solution
A vibration mode determining apparatus that includes a vibration command generating unit, a control unit, a motor drive unit, a vibration sensor, and a measurement-point information input unit, which calculates the vibration mode using the motor excitation force and sensor output, allowing for efficient and accurate determination of machine vibration modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impulse hammer is used for vibration excitation, then vibration mode determination can be performed, but user burden increases due to manual hitting actions required
Solution Approach 1:
The motor drive unit serves dual purposes: normal operation and vibration excitation. The vibration command generating unit generates vibration commands that are processed through the control unit to drive the motor, which then vibrates the machine structure automatically without requiring manual impulse hammer operations. This self-service approach eliminates user burden while maintaining reliable vibration mode determination.
2Ease of operation
If a vibrator is used for vibration excitation, then automated vibration excitation is achieved, but machine size restrictions apply due to space requirements
Solution Approach 1:
The motor is designed to perform both its primary function of driving the machine and the secondary function of vibration excitation. By using the motor itself as the vibration source rather than requiring a separate vibrator, the system eliminates space restrictions. The control unit generates vibration commands that modulate the motor operation, enabling automated vibration excitation without additional components.
3Reliability
If conventional vibration excitation methods are used, then vibration mode determination is possible, but insufficient excitation force is exerted on large-sized machines
Solution Approach 1:
The motor drive unit utilizes the motor's own capability to generate sufficient excitation force. Since the motor is already designed to drive the machine structure, its inherent force generation capacity is leveraged for vibration excitation. This self-service approach ensures that adequate excitation force is applied to large-sized machines without requiring external vibration exciters.
4Measurement precision
If sensor orientation data processing is performed manually, then accurate vibration mode determination is possible, but processing complexity and time increase
Solution Approach 1:
The control unit receives vibration commands and processes them through feedback loops to generate appropriate motor current commands. The vibration command generating unit creates commands based on predetermined patterns, and the control unit adjusts the motor operation accordingly. This automated feedback mechanism handles sensor orientation data processing internally, maintaining measurement precision while reducing manual processing complexity and time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus enables reliable and efficient determination of vibration modes in machines with multiple motors, reducing user burden and size-related restrictions, while providing high accuracy and broad-band vibration excitation.
Implementation Method 1
a motor drive unit that receives the motor current command from the control unit and drives the motor
Implementation Method 2
a vibration sensor that detects vibration of the machine structure
Data Source
AI summary
A vibration mode determining apparatus that determines vibration mode of a machine structure of a machine including motors and that includes a vibration command generating unit that generates a vibration command for the motor; a control unit that generates a current command for the motor according to the vibration command and outputs a conversion value for a motor excitation force to a vibration mode calculating unit; a motor drive unit that receives the motor current command and drives the motor; a vibration sensor that detects vibration of the machine structure; a measurement-point information input unit that sets information about the attachment point of the vibration sensor; a vibration mode calculating unit that calculates the vibration mode using the conversion value for the motor excitation force and the output of the vibration sensor; and a vibration mode output unit that outputs the vibration mode.