Dual-Servo Resonance Suppression Using a Single Power Converter
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Solution Overview
Problem
Current machine tools face challenges in resonance suppression when using two servo motors in parallel, leading to instability, reliability issues, and increased manufacturing and maintenance costs due to the need for multiple inverters and servo drives, which hinders miniaturization and productivity.
Innovation Solution
An apparatus and method that adjust electrical energy applied to first and second servo motors from a single power conversion part based on an invalid torque command to suppress resonance, using a single servo drive and power conversion part, thereby enhancing stability, reliability, and precision of automatic tool changers and palette changers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If two servo motors operate in parallel with separate inverters and servo drives, then sufficient torque and force can be obtained, but the device size increases, manufacturing costs and maintenance costs increase
Solution Approach 1:
The patent merges two separate inverter systems into a single inverter that controls both servo motors. The inverter output is divided into two channels, each driving one servo motor, thereby reducing the number of inverters from two to one while maintaining the parallel operation capability of the two motors for sufficient torque output.
Solution Approach 2:
The single inverter is designed with multi-functionality to control both servo motors simultaneously. It includes separate PWM generation units and control channels that can independently regulate each motor while sharing common power conversion components, achieving universal control capability.
2Force
If two servo motors operate in parallel with separate inverters and servo drives, then sufficient torque can be obtained, but manufacturing costs and maintenance costs increase
Solution Approach 1:
The patent combines two separate inverter systems into one unified inverter, reducing the total component count. This merging eliminates redundant power conversion circuits, control boards, and associated components, directly lowering manufacturing material costs and assembly complexity.
Solution Approach 2:
The single inverter is designed as a universal control unit that can simultaneously manage both servo motors through independent control channels. This multi-functional design reduces per-unit costs by eliminating the need for duplicate expensive inverter assemblies while maintaining full operational capability.
3Device complexity
If a single power conversion part and single servo drive control two servo motors, then device size is reduced and costs are lowered, but resonance occurs leading to instability and reliability issues
Solution Approach 1:
The patent implements a feedback mechanism where the control unit monitors the operational state of both servo motors and dynamically adjusts control parameters. This feedback loop detects resonance conditions and modifies PWM signals to suppress vibrations, maintaining system stability despite the reduced hardware configuration.
Solution Approach 2:
The control system employs dynamic parameter adjustment based on real-time motor operation states. The inverter can dynamically change switching frequencies, PWM duty cycles, and control gains to adapt to varying load conditions and suppress resonance, ensuring reliable operation across different working conditions.
4Device complexity
If a single power conversion part and single servo drive control two servo motors, then device size is reduced, but resonance occurs affecting precision
Solution Approach 1:
The control unit uses feedback from motor position and speed sensors to detect resonance-induced position deviations. It dynamically adjusts control parameters to compensate for these deviations, maintaining manufacturing precision despite the presence of resonance in the reduced-hardware configuration.
Solution Approach 2:
The system dynamically adjusts control parameters including PWM frequency and duty cycle based on real-time motor operation states. This dynamic adaptation allows the system to suppress resonance effects that would otherwise degrade positioning precision, maintaining high manufacturing accuracy.
Data Source
AI summary
An apparatus for controlling resonance suppression of a machine tool according to the present disclosure includes: a numerical control part; a main operation part; a PLC configured to execute a control command by means of communication with the numerical control part or the main operation part; a servo drive configured to execute the control command of the PLC; a servo motor part configured to operate under control of the servo drive; and a power conversion part electrically connected to the servo motor part and the servo drive and configured to apply electrical energy to the servo motor part, wherein the power conversion part controls resonance suppression in accordance with an operation of the servo motor part by adjusting electrical energy to be applied to the servo motor part based on a signal from the servo drive.