Encoder Signal Correction for Servo Motor Position Accuracy
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Solution Overview
Problem
Conventional systems for determining the rotary position of a servo motor are not sufficiently accurate due to impairments such as phase offsets, DC offsets, and amplitude mismatches in the signals from photo detectors, which affect the computation of the motor's position.
Innovation Solution
An encoder system with a first correction circuit for applying fixed gain and DC offset correction, and a second correction circuit for dynamic gain and DC offset correction, is used to preprocess the signals before computing the phase and rotary position of the servo motor, ensuring accurate signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional encoder systems are used to determine rotary position, then the system structure is simple, but the measurement precision is insufficient due to signal impairments
Solution Approach 1:
The patent applies preliminary action by performing offset and gain correction on the photo detector signals before they are used for position computation. The correction circuits pre-process the signals to remove impairments (offsets, gain mismatches) that would otherwise degrade measurement precision. This advance correction ensures that the subsequent position calculation operates on clean, calibrated signals, resolving the contradiction by improving accuracy without requiring fundamental changes to the encoder architecture.
Solution Approach 2:
The patent introduces correction circuits as intermediary components between the photo detectors and the position computation logic. These intermediary circuits act as mediators that condition the raw signals by removing offsets and correcting gain mismatches before the signals reach the position calculation stage. This intermediary processing layer improves measurement precision while maintaining the overall system structure, effectively resolving the technical contradiction.
2Measurement precision
If signal correction circuits are added to improve position accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the signal correction function into two distinct correction circuits: one for offset correction and another for gain correction. This segmentation allows each circuit to perform a specific function with dedicated logic, improving measurement precision through systematic correction while keeping each individual correction module relatively simple. The divided approach resolves the contradiction by achieving high precision through modular, manageable correction stages rather than a single complex correction system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively removes phase offsets and DC offsets, allowing for precise computation of the servo motor's phase and position, even in the presence of impairments, thereby enhancing the accuracy of the rotary position determination.
Implementation Method 1
a light source, such as light emitting diodes (LEDs)
Implementation Method 2
a photo detector, and a disc with slots (the combination of these is generally referred to as an optical encoder)
Data Source
AI summary
Various embodiments of the present technology comprise a method and apparatus for an encoder. In various embodiments, the encoder is configured to perform offset and gain correction. The encoder includes a first correction circuit to perform offset and gain correction and a second correction circuit to perform additional offset and gain correction.