Chatter Vibration Suppression via Variable Rotation Speed Control
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Solution Overview
Problem
Existing methods for suppressing chatter vibration in machine tools require determining the moment of inertia for each workpiece and machine tool, leading to increased operational steps and a risk of motor breakdown due to excessive acceleration and deceleration.
Innovation Solution
A method that calculates and records the moment of inertia once for the machining program, allowing for easy variation of rotation speed to suppress chatter vibration without motor breakdown, by using a machine tool with a moment of inertia acquisition unit, recording unit, and calculating unit to determine a variable amplitude and period based on the stored moment of inertia and maximum motor power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotating shaft is repeatedly accelerated and decelerated sharply to suppress chatter vibration, then the chatter vibration suppressing effect is improved, but the motor may produce heat and break due to increased input power
Solution Approach 1:
The patent changes the parameters of rotation speed variation (amplitude and period) based on the moment of inertia calculation. By optimizing these parameters according to the specific workpiece and machine tool combination, the system achieves effective chatter suppression while keeping the acceleration and deceleration within safe limits for the motor, thus preventing motor breakdown.
2Reliability
If a dedicated operation is performed to determine the moment of inertia for each workpiece and machine tool combination, then the rotation speed variation can be optimized, but the number of work steps increases and the process becomes less rational
Solution Approach 1:
The patent performs the moment of inertia determination operation in advance and stores the result. This preliminary action eliminates the need to repeat the determination for each subsequent machining operation with the same workpiece and machine tool combination, thereby reducing the number of work steps while maintaining accurate rotation speed control.
Solution Approach 2:
The patent creates a universal solution by determining the moment of inertia once for a given workpiece-machine tool combination and reusing this information across multiple machining operations. This universal approach makes the process more rational and efficient, as the same moment of inertia value can be applied to different machining steps without requiring redetermination.
3Reliability
If the same workpiece is machined by another machine tool, then the previously determined moment of inertia cannot be used, requiring the same dedicated operation again
Solution Approach 1:
The patent segments the moment of inertia into two components: the moment of inertia of the rotating body (workpiece + tool) and the moment of inertia of the machine tool's rotating parts. By separating these components, the system can transfer the workpiece-related moment of inertia between different machine tools, requiring only the machine tool's own rotating part inertia to be added, thus reducing the need for complete redetermination.
Data Source
AI summary
A chatter vibration suppressing method includes acquiring a moment of inertia of a rotating body, recording a value indicating the acquired moment of inertia into a machining program, and calculating a variable amplitude and a variable period when a rotation speed of the rotating body is varied in order to suppress chatter vibration from the value indicating the moment of inertia recorded in the machining program and the maximum input power of a motor for rotating the rotating body.