Multiturn Angle Detection With Single-Sensor Pulse Counting
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Solution Overview
Problem
Existing multiturn angle detection devices are hindered by size and cost issues due to the use of multiple power generation sensors, and they struggle with pulse missing, which complicates the determination of rotation direction and requires complex signal processing.
Innovation Solution
A multiturn angle detection device utilizing a single power generation sensor, a magnetic field generation source, and a precision absolute angle detector, which generates a multiturn absolute angle detection value by combining count values without complex signal processing, ensuring precise angle detection even with pulse missing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple power generation sensors are used to detect rotation direction and prevent pulse missing, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the detection task into two parts: a single power generation sensor detects pulse signals for turn counting, while a separate absolute angle detector provides precise angle information within each turn. This segmentation allows the system to achieve high precision without using multiple power generation sensors, thereby reducing device complexity and cost.
Solution Approach 2:
The patent introduces an absolute angle detector as an intermediary component that works alongside the power generation sensor. The absolute angle detector provides reference angle information that helps determine rotation direction and corrects for pulse missing, enabling accurate multiturn angle detection without requiring multiple power generation sensors.
2Reliability
If multiple power generation sensors are used to ensure reliable rotation direction determination, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the detection system into a power generation sensor for turn counting and an absolute angle detector for precise angle measurement within each turn. This segmentation improves reliability by providing multiple independent detection mechanisms while controlling manufacturing cost by using only one power generation sensor instead of multiple.
Solution Approach 2:
The patent implements feedback by using the absolute angle detector to monitor the angle within each turn and comparing it with the count value from the power generation sensor. This feedback mechanism ensures reliable rotation direction determination by detecting inconsistencies and correcting for pulse missing, thereby improving reliability without increasing the number of power generation sensors.
3Measurement precision
If complex signal processing is used to correct pulse missing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by using the absolute angle detector to continuously monitor the angle within each turn before pulse missing occurs. This allows the system to establish a reference angle that can be used to detect and correct pulse missing events, improving measurement precision without requiring complex real-time signal processing.
Solution Approach 2:
The patent replaces complex mechanical signal processing with a simpler approach by using the absolute angle detector to directly measure the angle within each turn. This substitution eliminates the need for complex signal processing algorithms to correct pulse missing, as the absolute angle detector provides direct angle information that can be combined with the power generation sensor count value.
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 device achieves size reduction and cost-effectiveness by using a single power generation sensor, while ensuring precise multiturn angle detection without complex signal processing, even when pulse missing occurs.
Implementation Method 1
Magnetic wires having a large Barkhausen effect (large Barkhausen jump) are known in the name of Wiegand wire or pulse wire
Implementation Method 2
A power generation sensor is produced by winding a coil around the magnetic wire. When the hard layer and the soft layer are magnetized in the same direction axially of the wire and the strength of an external magnetic field applied in a direction opposite to that magnetization direction is increased to a certain magnetic field strength, the magnetization direction of the soft layer is reversed. At this time, the large Barkhausen effect is exhibited to induce a pulse signal in the coil wound around the magnetic wire.
Data Source
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Figure 3A~3C
AI summary
A multiturn angle detection device is provided, which generates the multiturn absolute angle detection value of a rotating body that is rotated about a rotation axis. The multiturn angle detection device includes: a segment counter to count segments defined by dividing the single-turn cycle of the rotating body in an angular range over the single turn of the rotating body; a precision absolute angle detector to generate an absolute angle detection value within the single-turn cycle of the rotating body; and an arithmetic device to generate the multiturn absolute angle detection value by combining the outputs of the segment counter and the precision absolute angle detector with each other. The segment counter includes: a single power generation sensor; a magnetic field generation source; a sensor element; and a nonvolatile memory to store a count value. The magnetic field generation source applies a k-cycle alternating magnetic field (wherein k is an integer not smaller than 3) per each turn of the rotating body axially of a magnetic wire. The arithmetic device uses the count value stored in the nonvolatile memory as it is when receiving external electric power supply, and combines the count value with the absolute angle detection value of the precision absolute angle detector.