Multiturn Angle Detection with Single-Sensor Pulse Counting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiturn angle detection devices using power generation sensors are large and costly due to the need for multiple sensors and complex signal processing to determine rotation direction and correct for pulse missing, which complicates precise angle detection.
Innovation Solution
A multiturn angle detection device utilizing a single power generation sensor with a magnetic wire exhibiting a large Barkhausen effect, combined with a precision absolute angle detector, determines rotation direction and compensates for pulse missing through a novel algorithm that updates count values based on voltage pulse polarity and sensor element state, without requiring external power for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple power generation sensors are used to determine rotation direction and correct for pulse missing, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the magnetic field cycle into multiple phases and uses a single power generation sensor to detect pulse signals at different segments. By dividing the detection task into temporal segments rather than using multiple simultaneous sensors, the system achieves multi-position detection capability with reduced hardware complexity
Solution Approach 2:
The patent applies preliminary magnetic field treatment by pre-magnetizing the magnetic wire and establishing specific magnetic field conditions before detection. This preliminary action ensures that the single sensor can reliably detect pulse signals corresponding to different rotational positions without requiring complex real-time processing or multiple sensors
2Reliability
If multiple power generation sensors are used to determine rotation direction and correct for pulse missing, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The single power generation sensor performs multiple functions: detecting rotational position, determining rotation direction, and providing pulse signals for counting. By making the single sensor multi-functional through clever signal processing and magnetic field management, the system achieves the reliability of multiple sensors without the associated manufacturing cost
Solution Approach 2:
The magnetic wire structure inherently provides self-service by automatically generating distinguishable pulse signals at different magnetic field phases during rotation. The system utilizes the natural magnetic properties of the wire to provide its own reference signals, eliminating the need for external reference sensors or complex calibration procedures
3Measurement precision
If complex signal processing is used to determine rotation direction and correct for pulse missing, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent employs periodic magnetic field cycling through the rotation of the magnetic field generation source, which naturally produces periodic pulse signals from the power generation sensor. This periodic action creates a rhythmic detection pattern that simplifies signal processing and enables rapid determination of rotational parameters without complex computational delays
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
Enables precise multiturn absolute angle detection with reduced size and cost by using a single power generation sensor, effectively compensating for pulse missing and generating accurate count values without complex signal processing.
Implementation Method 1
Magnetic wires having a large Barkhausen effect (large Barkhausen jump) are known in the name of Wiegand wire or pulse wire... When the external magnetic field strength is increased to a certain magnetic field strength, the magnetization direction of the soft layer is reversed. The reversal of the magnetization direction starts at a certain position of the magnetic wire to propagate to the entire wire, whereby the magnetization direction of the soft layer is totally reversed. At this time, the large Barkhausen effect is exhibited to induce a pulse signal in the coil wound around the magnetic wire.
Implementation Method 2
A power generation sensor is produced by winding a coil around the magnetic wire... A voltage outputted from the coil is characteristically constant irrespective of the change rate of an input magnetic field (external magnetic field), and is free from chattering because of its hysteresis with respect to the input magnetic field.
Implementation Method 3
A voltage outputted from the coil is characteristically constant irrespective of the change rate of an input magnetic field (external magnetic field), and is free from chattering because of its hysteresis with respect to the input magnetic field.
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A multiturn angle detection device includes: a segment counter to count segments defined by dividing the single-turn cycle of a rotation shaft in an angular range over the single turn of the rotation shaft; a precision absolute angle detector to generate an absolute angle detection value within the single-turn cycle of the rotation shaft; and an arithmetic device to generate a multiturn absolute angle detection value by combining the output of the segment counter with the output of the precision absolute angle detector. 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 two or more-cycle alternating magnetic field per each turn of the rotation shaft axially of a magnetic wire. The arithmetic device uses the count value stored in the nonvolatile memory as it is to combine the count value with the absolute angle detection value of the precision absolute angle detector when receiving external electric power supply.