Encoder Signal Correlation for High-Speed Motor Position Sync
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Solution Overview
Problem
Existing motor drive systems face challenges in accurately correlating high-speed feedback signals with limited angular position resolution due to finite sampling intervals, leading to decreased precision in synchronized operations, particularly in industrial processes with repeated motions.
Innovation Solution
A substrate-mounted control circuit within the motor synchronizes input signals with enhanced sampling rates, correlating position feedback signals at frequencies up to ten times faster than conventional motor drives, allowing precise synchronization of input data with motor position or time, and transmitting this data to external controllers via an industrial network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor drive samples the position feedback signal at a finite interval to execute control routines, then the control system can generate switching signals for power electronic devices, but the resolution of angular position determination decreases as motor speed increases
Solution Approach 1:
The system performs preliminary interpolation calculations between sampled position values to estimate intermediate position values. This allows the system to determine angular position with higher resolution than the sampling interval would normally permit, effectively preparing position data in advance for more precise speed-dependent position determination.
Solution Approach 2:
The patent replaces the purely hardware-based sampling approach with a hybrid system that uses software-based interpolation algorithms. This substitution allows mathematical computation to enhance the effective resolution of position measurements without requiring faster physical sampling hardware.
2Ease of operation
If the motor drive uses a finite sampling interval for position feedback, then the control routine can execute within the sampling period, but the synchronization accuracy between input signals and motor position deteriorates
Solution Approach 1:
The system pre-calculates interpolated position values between samples and stores them for later retrieval. When synchronization is needed, the system can quickly determine accurate position values without waiting for the next sample, thereby maintaining control routine simplicity while improving synchronization accuracy.
Solution Approach 2:
The interpolation algorithm acts as an intermediary between the sampled position feedback signal and the control system's position requirements. It translates discrete samples into continuous position information, enabling accurate synchronization without requiring the control routine to execute at the high sampling rate.
3Power
If the motor drive samples position at the same rate as switching signal generation, then the control system maintains real-time operation, but the resolution of position correlation with external feedback signals decreases
Solution Approach 1:
The system pre-computes interpolated position values and maintains a buffer of these values for correlation with external feedback signals. This allows the system to provide high-resolution position data for synchronization purposes without requiring the main control loop to run faster, preserving real-time control capability while improving correlation resolution.
Solution Approach 2:
The patent separates the position determination function into two independent operations: the main control loop that generates switching signals at its required rate, and an interpolation function that provides high-resolution position values for synchronization. This segmentation allows each function to operate at its optimal rate without compromising the other.
Data Source
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AI summary
A system for correlating an input signal with an operating state of a motor includes a substrate which is either integral to an encoder or mounted on the motor. The substrate has a first input connected to a sensor proximate to the motor to receive a first signal from the sensor. The substrate also includes a second input to receive a position feedback signal from the encoder. A control circuit is operative to detect a change in state of the first signal and to correlate at least one additional signal to the change in state of the first signal. A data packet including the first signal and the at least one additional signal correlated at the change in state is generated. A communication interface is operative to transmit the data packet from the control circuit to at least one additional controller external from the motor.