Servo Control Phase Velocity Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional servo control devices face challenges in achieving high-precision control due to noise-like signals from second-order differentials, phase delays when using pseudo differentials, and limited ability to handle specific command shapes, especially when dealing with control targets of low rigidity.
Innovation Solution
A servo control device that includes a follow-up control unit, a command function unit, a second derivative unit, and a correction-value computation unit, which uses a phase signal to calculate a motor motion command by multiplying the square of the phase velocity with the second-order differential base signal and a constant, thereby correcting the motor motion command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a second-order differential of a position command is performed to generate a correction value, then control precision is improved, but the signal becomes noise-like and high-precision control becomes difficult
Solution Approach 1:
The patent introduces a phase signal as an intermediary variable that represents the cyclic operation state. Instead of directly differentiating the position command with respect to time, the system differentiates with respect to the phase signal, which acts as a mediator between the time-varying command and the correction value generation.
Solution Approach 2:
The patent changes the parameter used for differentiation from time to phase signal. By using phase signal as the differentiation variable and multiplying by phase velocity squared, the system achieves the same control effect without the noise amplification problem associated with direct time-based second-order differentiation.
2Object-affected harmful factors
If a pseudo differential is used instead of pure differential to reduce noise, then noise is suppressed, but phase delay occurs and high-precision control becomes difficult
Solution Approach 1:
The phase signal serves as an intermediary that allows the system to compute derivatives without introducing phase delay. By using the phase signal and its derivative (phase velocity) as intermediaries, the system avoids the phase-lagging characteristic of pseudo-differential methods while still achieving noise suppression.
Data Source
AI summary
A servo control device includes a follow-up control unit that controls a control target that drives a mechanical system by a motor, a command function unit that has input therein a phase signal θ indicating a phase of a cyclic operation performed by the control target, and that calculates a machine motion command according to the phase signal θ by a preset first function, a second derivative unit that uses a second function obtained by second-order differentiating the first function with respect to the phase signal to calculate a value of the second function according to the phase signal as a second-order differential base signal, a correction-value computation unit that computes a first command correction value for correcting the motor motion command by using a product of a square value of the phase velocity, the second-order differential base signal, and a first constant, and a correction-value addition unit that calculates the motor motion command based on an added value of the first command correction value and the machine motion command.