Servo Control Device for High-Speed Tracking Accuracy
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Solution Overview
Problem
In servo control systems for machining, the combination of low-speed and high-speed servo systems fails to accurately track command values due to differing response delays, leading to tracking errors and insufficient response, especially at high speeds.
Innovation Solution
A servo control device that controls both a low-speed and a high-speed servo system by creating a combined position target value and using transfer functions to convert it into command values for each system, ensuring the product of the first and second model transfer functions coincides, thereby eliminating the impact of response differences between the systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one motor is used for one direction of movement in servo control, then the control system is simple, but tracking error occurs due to response delay and rapid response cannot be achieved
Solution Approach 1:
The patent divides the single servo control system into two separate servo systems: a low-speed servo system and a high-speed servo system. Each system uses a dedicated motor optimized for specific speed ranges, allowing the low-speed system to handle steady-state positioning while the high-speed system addresses rapid movements and corrections, thereby eliminating tracking errors without excessive complexity
Solution Approach 2:
The patent implements dynamic switching between two servo systems based on operational requirements. The low-speed servo system operates during normal machining, while the high-speed servo system activates during rapid movements or corrections. This dynamic allocation optimizes both tracking accuracy and response speed without requiring both systems to operate simultaneously at full complexity
2Speed
If an additional motor with rapid response is added to create a cooperative control system, then response speed improves, but tracking accuracy deteriorates due to different response delays between systems
Solution Approach 1:
The patent implements a feedback mechanism where the actual positions of both the low-speed and high-speed servo systems are continuously monitored. The control unit compares the combined actual position with the command value and adjusts the distribution of command values between the two systems in real-time, compensating for differences in response delays and maintaining high tracking accuracy
Solution Approach 2:
The patent dynamically adjusts the command value distribution parameters between the two servo systems based on their respective response characteristics. By changing the allocation ratio of command values according to operational conditions and system responses, the patent optimizes both speed and accuracy without requiring identical response delays from both systems
Data Source
AI summary
A servo control device controls a combined position of a first servo system and a second servo system having higher response than response of the first servo system. The servo control device includes a first axis target value creation unit and a correction unit. The first axis target value creation unit creates a first axis target value based on a combined command value which is a position command value of the combined position. The correction unit converts the first axis target value into a first axis command value by using a first transfer function. In addition, the correction unit converts the first axis target value by using a second transfer function, and calculates a second axis command value by subtracting the converted first axis target value from the combined command value. The product of the first transfer function and a first model transfer function which models characteristics of the first servo system is equal to the product of the second transfer function and a second model transfer function which models characteristics of the second servo system.