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Gill Sensors & Controls Ltd.
Inductive Position Sensing with
Single Coil Elements
Gill Sensors & Controls Ltd &
Industrial Electronic Controls Inc.
• Inductive Position Sensing Technology & Working Princi...
• Present basic working principles of an inductive position
sensing technology
• Introduce performance differentiators wit...
Industrial Electronic Controls designs and manufactures
a variety of foot pedal, joystick and sensor products to
suit mult...
Jon Klein – Vice President Engineering
Industrial Electronic Controls
Paul Cain – Manager New Business Development,
North ...
• Present basic working principles of Gill’s single coil
inductive technology
• Introduce Technological Differentiators wi...
Pulse Induction
Metal Detector
Inductive Loop
Traffic Sensors
Working principle of inductive coil technologies
The target (or activator) is simply a piece of mild steel with a specific shape
Three basic components: the coil, the targ...
Present basic working principles of an inductive position sensing technology
A1-Activator
C1 -Coil
P1 -Processor
Current D...
Step 1 The processor sends a known pulse of energy to the coil, (Gold
Trace). This results in a magnetic field radiating a...
Step 2 The processor then switches modes and using the same coil, prepares for receive
mode. This is a ‘settle’ state, not...
This pulse of energy is absorbed by the mild steel activator in the form of
eddy currents
Step 3 The processor then switch...
Steps 1 and 3 showing transmitter mode (Gold) pulse and receiver mode
(red) pulse.
Step 4 the processor measures these two eddy current levels, along with the
time duration, comparing these two residual ed...
Step 5 The processor compares the two eddy current levels and arrives at a specific
amount of eddy current decay in the ac...
T0 T1 T6 T7T4 T5T2 T3
Changes in Activator position are monitored over 1,000 times per second
Each new position of the Act...
Adding a second coil brings ratiometric properties to the sensor
A 2 coil design improves:
-Temperature stability
-The abi...
DUAL COIL DESIGN
Both Coils need to be observing eddy currents from the (single) activator
The processor begins storing an...
Definition: Absolute Position is the inherent characteristic of a position sensor to
know its true location at power on / ...
The design’s tolerance to misalignment in mechanical sub-assemblies
The design’s tolerance to misalignment in mechanical sub-assemblies
The design’s tolerance to misalignment in mechanical sub-assemblies
The design’s tolerance to misalignment in mechanical sub-assemblies
The design’s tolerance to misalignment in mechanical sub-assemblies
Two main components in Gill’s 1st Generation Inductive rotary angle sensor
Dual Activators on a shaft Sensor Electronics &...
https://youtu.be/z--K8PBfK38?t=89
Video of Gill Gen I Dual Cavity Sensor
Jon Klein
Vice President of Engineering
Industrial Electronic Controls Inc.
Design characteristics that are typical in an existing Industrial pedal application
where mechanical play was of concern (...
Decision criteria in selecting a rotary angle sensor
-Tolerance to misalignment over lifetime
-Environmental sealing witho...
Exploded view of full pedal assembly
1- There are 2 bushings pressed in the arms
This pressing operation allows for the
po...
Exploded view of full pedal assembly
4- There are 2 weld bushings -one on
each arm. The bushing’s final
positioning at the...
Return Spring
Brake Pedal Arm (section view)
Bearing
Nut & bolt compressing
sub assy.
Inductive Coils
Moving activator 1Mo...
Summary
-Designing for end-of-life mechanical conditions
-High tolerance to misalignment
-Independent outputs
-Ignores lar...
Inductive Position Sensing with Single Coil Elements Using Time Discrimination
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Inductive Position Sensing with Single Coil Elements Using Time Discrimination

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A Gill Sensors & Controls and IEC technical presentation ‘Inductive Position Sensing with Single Coil Elements Using Time Discrimination’ which discussed the key principles of their induction technology. Discover how utilising the technology can improve aspects of performance in demanding applications including, off-highway, process machinery and construction vehicles.

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Inductive Position Sensing with Single Coil Elements Using Time Discrimination

  1. 1. Gill Sensors & Controls Ltd. Inductive Position Sensing with Single Coil Elements
  2. 2. Gill Sensors & Controls Ltd & Industrial Electronic Controls Inc. • Inductive Position Sensing Technology & Working Principle • Industrial Application in Production Volumes
  3. 3. • Present basic working principles of an inductive position sensing technology • Introduce performance differentiators with this technology’s ability to: Be immune to thermal shifts Tolerance to local magnetic interference Achieve true absolute position Tolerate mechanical misalignment in the mating mechanical assy. • Provide details on an existing Industrial pedal application where mechanical play was of concern (IEC) Gill Sensors & Controls Ltd / IEC
  4. 4. Industrial Electronic Controls designs and manufactures a variety of foot pedal, joystick and sensor products to suit multiple industrial control applications Gill Sensors is a leading UK based manufacturer of sensors used in Construction, Agriculture, Motorsport, Defense, Marine and Material handling industries. Products include: non-contact rotary and linear position sensing, liquid level sensing, oil condition monitoring and fluid flow sensing Original Equipment ManufacturersEnd Usage
  5. 5. Jon Klein – Vice President Engineering Industrial Electronic Controls Paul Cain – Manager New Business Development, North America Co-Authors
  6. 6. • Present basic working principles of Gill’s single coil inductive technology • Introduce Technological Differentiators with Gill’s ratiometric properties with the second, third, coil: Immune to thermal shifts Ability to achieve true absolute position Tolerance to mechanical misalignment in the mating mechanical assy. • Provide details on an existing Industrial application where mechanical play was of concern (IEC) Gill’s Inductive Position Sensor
  7. 7. Pulse Induction Metal Detector Inductive Loop Traffic Sensors Working principle of inductive coil technologies
  8. 8. The target (or activator) is simply a piece of mild steel with a specific shape Three basic components: the coil, the target (activator) and Gill’s proprietary signal processing electronics. Gill’s Single Coil Inductive Position Sensing Technology
  9. 9. Present basic working principles of an inductive position sensing technology A1-Activator C1 -Coil P1 -Processor Current Day Standard Product
  10. 10. Step 1 The processor sends a known pulse of energy to the coil, (Gold Trace). This results in a magnetic field radiating across the airgap
  11. 11. Step 2 The processor then switches modes and using the same coil, prepares for receive mode. This is a ‘settle’ state, noting the switch position
  12. 12. This pulse of energy is absorbed by the mild steel activator in the form of eddy currents Step 3 The processor then switches modes and using the same coil, now in receiver mode, begins to measure the remaining energy that resides in the activator
  13. 13. Steps 1 and 3 showing transmitter mode (Gold) pulse and receiver mode (red) pulse.
  14. 14. Step 4 the processor measures these two eddy current levels, along with the time duration, comparing these two residual eddy currents. Reading To and T1 t0 t1
  15. 15. Step 5 The processor compares the two eddy current levels and arrives at a specific amount of eddy current decay in the activator. Knowing these two energy states, the processor calculates the size of the energy drop, plus the known time delay and calculates the current position of the activator
  16. 16. T0 T1 T6 T7T4 T5T2 T3 Changes in Activator position are monitored over 1,000 times per second Each new position of the Activator has a unique slope in eddy current decay (red curve) Each of processor iteration results in a new position in linear activator movement
  17. 17. Adding a second coil brings ratiometric properties to the sensor A 2 coil design improves: -Temperature stability -The ability to calculate absolute position and direction -Mechanical tolerance immunity -i.e. uncontrolled movement in other axis -Susceptibility to outside magnetic influences. A1-Activator C1 & C2 Coils P1 -Processor
  18. 18. DUAL COIL DESIGN Both Coils need to be observing eddy currents from the (single) activator The processor begins storing and comparing both coil results. Both coils will be reading the decayed energy for the exact same duration but in sequence of C1, C2, C1, C2, etc). T0 T1 T2 T3 The design effectively ignores temperature fluctuations The processor ‘knows’ both coils are reading a target that is the same temperature, by observing the same target, hot or cold, any relative change in energy state has to be a change in position, not a temperature induced energy change.
  19. 19. Definition: Absolute Position is the inherent characteristic of a position sensor to know its true location at power on / off / on. When turned back ‘on’, an absolute sensor begins broadcasting its actual position without requiring any movement or triggering of an index pulse or any reference positioning. This absolute characteristic applies even when the sensor has been moved during the ‘off’ event.
  20. 20. The design’s tolerance to misalignment in mechanical sub-assemblies
  21. 21. The design’s tolerance to misalignment in mechanical sub-assemblies
  22. 22. The design’s tolerance to misalignment in mechanical sub-assemblies
  23. 23. The design’s tolerance to misalignment in mechanical sub-assemblies
  24. 24. The design’s tolerance to misalignment in mechanical sub-assemblies
  25. 25. Two main components in Gill’s 1st Generation Inductive rotary angle sensor Dual Activators on a shaft Sensor Electronics & Coils The Complete Assembly
  26. 26. https://youtu.be/z--K8PBfK38?t=89 Video of Gill Gen I Dual Cavity Sensor
  27. 27. Jon Klein Vice President of Engineering Industrial Electronic Controls Inc.
  28. 28. Design characteristics that are typical in an existing Industrial pedal application where mechanical play was of concern (IEC) -Long cycle life -Heavy side loading -Bearing wear -Possible location close to large electric motors -Tight packaging constraints -High importance on robustness and reliability Application History on a Steering Column Mounted Pedal Assy (Industrial Vehicle)
  29. 29. Decision criteria in selecting a rotary angle sensor -Tolerance to misalignment over lifetime -Environmental sealing without bearings or rotary seals -Unit price -Independent Outputs -End of shaft style sensors -Elimination of (internal) return springs as an anti-hysteresis compensator -fewer parts = fewer failure modes -broad input voltage range +5V to +48V
  30. 30. Exploded view of full pedal assembly 1- There are 2 bushings pressed in the arms This pressing operation allows for the possibility of mechanical misalignment 2- When the Pivot Tube is tightened down it reduces the axial movement of the other components.
  31. 31. Exploded view of full pedal assembly 4- There are 2 weld bushings -one on each arm. The bushing’s final positioning at the weld operation can contribute to activator misalignment 5- The separation washer thickness is used to control the minimum gap between the two arms.
  32. 32. Return Spring Brake Pedal Arm (section view) Bearing Nut & bolt compressing sub assy. Inductive Coils Moving activator 1Moving activator 2 2 bushings / pedal Pivot tube Width of the mounting bracket tolerance allows for the arms to slide on the pivot tube.
  33. 33. Summary -Designing for end-of-life mechanical conditions -High tolerance to misalignment -Independent outputs -Ignores large magnetic interference -Withstands high pressure water blasting

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