U.S. patent application number 16/874810 was filed with the patent office on 2020-12-10 for system for sensing a position of a first member relative to a second member based on a radio frequency characteristic of a bias member.
The applicant listed for this patent is AVX Electronics Technology Limited. Invention is credited to Markus Fradrich, Jonathan Hayes, Jaakko Kyllonen, Olivier Pajona, Stephane Proust, Stefan Ruhl, David Witts.
Application Number | 20200384976 16/874810 |
Document ID | / |
Family ID | 1000004865920 |
Filed Date | 2020-12-10 |
United States Patent
Application |
20200384976 |
Kind Code |
A1 |
Witts; David ; et
al. |
December 10, 2020 |
System for Sensing a Position of a First Member Relative to a
Second Member Based on a Radio Frequency Characteristic of a Bias
Member
Abstract
A system for sensing a position of a first member relative to a
second member based on a radio frequency characteristic of a bias
member is disclosed. The bias member may be configured to bias the
second member relative to the first member. Radio frequency
circuitry may be configured to apply a radio frequency signal to
the bias member and provide one or more signals indicative of a
position of the first member relative to the second member based on
a radio frequency characteristic of the bias member.
Inventors: |
Witts; David; (Cambridge,
GB) ; Pajona; Olivier; (Antibes, FR) ;
Fradrich; Markus; (Werne an der Lippe, DE) ; Ruhl;
Stefan; (Werne an der Lippe, GB) ; Proust;
Stephane; (Cagnes-Sur-Mer, FR) ; Kyllonen;
Jaakko; (Antibes, FR) ; Hayes; Jonathan;
(Cambridge, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AVX Electronics Technology Limited |
Cambridge |
|
GB |
|
|
Family ID: |
1000004865920 |
Appl. No.: |
16/874810 |
Filed: |
May 15, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62857298 |
Jun 5, 2019 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01S 13/10 20130101;
B60W 10/198 20130101; B60W 2720/106 20130101; B60W 2510/0604
20130101; B60W 2050/0057 20130101 |
International
Class: |
B60W 10/198 20060101
B60W010/198; G01S 13/10 20060101 G01S013/10 |
Claims
1. A position sensor system comprising: a first member: a second
member movable relative to the first member; a bias member
configured to bias the second member relative to the first member;
and radio frequency circuitry configured to apply a radio frequency
signal to the bias member and provide one or more signals
indicative of a position of the first member relative to the second
member based on a radio frequency characteristic of the bias
member.
2. The position sensor system of claim 1, wherein the bias member
is coupled to each of the first member and second member.
3. The position sensor system of claim 1, wherein the bias member
is configured to bias the second member away from the first
member.
4. The position sensor system of claim 1, wherein the second member
is pivotally coupled to the first member.
5. The position sensor system claim 1, wherein the bias member
comprises a coil spring.
6. The position sensor system of claim 1, wherein the radio
frequency circuity comprises a radio frequency generator
electrically coupled with the bias member at a first location of
the bias member and configured to apply the radio frequency signal
to the bias member at the first location.
7. The position sensor system of claim 6, wherein the radio
frequency circuity comprises a spectrum analyzer electrically
coupled with the bias member at the first location of the bias
member and configured to detect the radio frequency signal
reflected by the bias member at the first location.
8. The position sensor system of claim 7, further comprising a
splitter having a first port, a second port, and a third port, and
wherein the first port is connected to the bias member at the first
location, and wherein the second port is connected to the frequency
generator, and wherein the third port is connected to the spectrum
analyzer such that each of the frequency generator and spectrum
analyzer are electrically coupled with the bias member at the first
location.
9. The position sensor system of claim 1, wherein the radio
frequency circuity comprises a spectrum analyzer configured to
detect an amplitude of a reflected radio frequency signal reflected
by the bias member.
10. The position sensor system of claim 9, wherein the one or more
signals indicative of the position of the first member relative to
the second member provided by the radio frequency circuity are
positively correlated with the amplitude detected by the spectrum
analyzer.
11. The position sensor system of claim 1, wherein the radio
frequency signal comprises a fixed amplitude sinusoidal signal.
12. The position sensor system of claim 11, wherein the fixed
amplitude sinusoidal signal has a frequency that ranges from about
50 MHz to about 2 GHz.
13. A position sensor system for a vehicle pedal comprising: a base
member; a pedal member movable relative to the base member; a bias
member configured to bias the pedal member away from the base
member; radio frequency circuitry configured to apply a radio
frequency signal to the bias member and provide one or more signals
indicative of a position of the base member relative to the pedal
member based on a radio frequency characteristic of the bias
member.
14. The position sensor system of claim 13, wherein the pedal
member comprises an accelerator pedal.
15. The position sensor system of claim 13, wherein the bias member
is coupled to each of the base member and pedal member, wherein the
pedal member is pivotally coupled to the base member.
16. The position sensor system of claim 13, wherein the bias member
comprises a coil spring.
17. The position sensor system of claim 13, wherein the radio
frequency circuity comprises a radio frequency generator
electrically coupled with the bias member at a first location of
the bias member and configured to apply the radio frequency signal
to the bias member at the first location.
18. The position sensor system of claim 17, wherein the radio
frequency circuity comprises a spectrum analyzer electrically
coupled with the bias member at the first location of the bias
member and configured to detect the radio frequency signal
reflected by the bias member at the first location, wherein the
position sensor system further comprises a splitter having a first
port, a second port, and a third port, and wherein the first port
is connected to the bias member at the first location, and wherein
the second port is connected to the frequency generator, and
wherein the third port is connected to the spectrum analyzer such
that each of the frequency generator and spectrum analyzer are
electrically coupled with the bias member at the first
location.
19. The position sensor system of claim 13, wherein the radio
frequency circuity: comprises a spectrum analyzer configured to
detect an amplitude of a reflected radio frequency signal reflected
by the bias member, wherein the one or more signals indicative of
the position of the base member relative to the pedal member are
positively correlated with the amplitude detected by the spectrum
analyzer.
20. A method for sensing a position of a first member relative to a
second member, the method comprising: applying a radio frequency
signal to a bias member that is configured to bias the second
member relative to the first member; detecting a radio frequency
characteristic of the bias member; and providing one or more
signals indicative of a position of the first member relative to
the second member based on the radio frequency characteristic of
the bias member.
Description
PRIORITY CLAIM
[0001] The present application claims the benefit of priority of
U.S. Provisional Application Ser. No. 62/857,298, filed on Jun. 5,
2019, titled "System for Sensing a Position of a First Member
Relative to a Second Member Based on a Radio Frequency
Characteristic of a Bias Member," which is incorporated herein by
reference.
FIELD
[0002] The present disclosure relates generally to radio frequency
sensors and related methods, and more specifically to systems and
methods for sensing a. position of a first member relative to a
second member based on a radio frequency characteristic of a bias
member.
BACKGROUND
[0003] Current position sensor systems for detecting relative
position between two members can generally be complex and
expensive. For example, some position sensors require additional
mechanical components that can contact each of the members. Such
systems can add undesirable resistance to relative movement between
the members. Other position sensors may generally require precisely
manufactured components, such as windings. Accordingly, an improved
position sensor system would be welcomed in the art.
SUMMARY
[0004] Aspects and advantages of embodiments of the present
disclosure will be set forth in part in the following description,
or may be learned from the description, or may be learned through
practice of the embodiments.
[0005] One example aspect of the present disclosure is directed to
a system for sensing a position of a first member relative to a
second member based on a radio frequency characteristic of a bias
member. The bias member may be configured to bias the second member
relative to the first member. Radio frequency circuitry may be
configured to apply a radio frequency signal to the bias member and
provide one or more signals indicative of a position of the first
member relative to the second member based on a radio frequency
characteristic of the bias member.
[0006] Another example aspect of the present disclosure is directed
to a position sensor system for a vehicle pedal. The system may
include a base member, a pedal member movable relative to the base
member, and a bias member configured to bias the pedal member away
from the base member. The system may include radio frequency
circuitry configured to apply a radio frequency signal to the bias
member and provide one or more signals indicative of a position of
the base member relative to the pedal member based on a radio
frequency characteristic of the bias member.
[0007] Another example aspect of the present disclosure is directed
to a method for sensing a position of a first member relative to a
second member. The method may include applying a radio frequency
signal to a bias member that is configured to bias the second
member relative to the first member; detecting a radio frequency
characteristic of the bias member; and providing one or more
signals indicative of a position of the first member relative to
the second member based on the radio frequency characteristic of
the bias member.
[0008] These and other features, aspects and advantages of various
embodiments will become better understood with reference to the
following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the present disclosure
and, together with the description, serve to explain the related
principles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Detailed discussion of embodiments directed to one of
ordinary skill in the art are set forth in the specification, which
makes reference to the appended figures, in which:
[0010] FIG. 1 depicts a schematic of select portions of an example
inductive position sensor including radio frequency circuity
according to example embodiments of the present disclosure;
[0011] FIG. 2 depicts a schematic of the example inductive position
sensor of FIG. 1 including an example configuration of a transmit
aerial, a receive aerial and a member having a ferrite coating
according to example embodiments of the present disclosure;
[0012] FIG. 3 is a schematic drawing of another embodiment of a
position sensor system employing a leaf spring bias member
according to aspects of the present disclosure
[0013] FIG. 4 depicts a flow diagram of an embodiment of a method
for sensing a position of a first member relative to a second
member according to aspects of the present disclosure; and
[0014] FIG. 5 is a plot of experimental data collected for a pedal
sensor assembly similar to the pedal assembly of FIG. 2.
DETAILED DESCRIPTION
[0015] Reference now will be made in detail to embodiments, one or
more examples of which are illustrated in the drawings. Each
example is provided by way of explanation of the embodiments, not
limitation of the present disclosure. In fact, it will be apparent
to those skilled in the art that various modifications and
variations can be made to the embodiments without departing from
the scope or spirit of the present disclosure. For instance,
features illustrated or described as part of one embodiment can be
used with another embodiment to yield a still further embodiment.
Thus, it is intended that aspects of the present disclosure cover
such modifications and variations.
[0016] Example aspects of the present disclosure are directed to
systems and methods for sensing a position of a first member
relative to a second member based on a radio frequency
characteristic of a bias member (e.g., a coil spring, or other
resilient member). The bias member may be configured to bias the
second member relative to the first member. Radio frequency (RF)
circuitry may be configured to apply a radio frequency signal to
the bias member and provide one or more signals indicative of a
position of the first member relative to the second member based on
a radio frequency characteristic of the bias member.
[0017] The radio frequency signal applied to the bias member can be
reflected by the bias member. The reflected radio frequency signal
can be detected by the radio frequency circuitry. The
characteristics of the radio frequency signal(s) (e.g., amplitude,
frequency, etc.) that is applied by the radio frequency circuitry
may be selected based on one or more characteristics of the system.
Example characteristics include dimensions or resonant frequencies
of the bias member and/or any surrounding conductive structure. For
instance, the radio frequency signal may have a frequency that
corresponds with a resonant frequency of the bias member (e.g., a
first resonant frequency, second resonant frequency, etc.).
[0018] The radio frequency circuity, or radio frequency circuit,
may include a radio frequency generator configured to apply the
radio frequency signal to the bias member, The radio frequency
circuit may also include a spectrum analyzer that is configured to
detect the radio frequency characteristic of the bias member. For
example, the spectrum analyzer may be configured to detect the
reflected radio frequency circuit that is reflected by the bias
member.
[0019] In some embodiments, the radio frequency generator and
spectrum analyzer may be coupled with the bias member at the same
location. For example, the radio frequency generator electrically
may be coupled with the bias member at a first location of the bias
member and configured to apply the radio frequency signal to the
bias member at the first location. The spectrum analyzer may be
electrically coupled with the bias member at the first location of
the bias member and configured to detect the radio frequency signal
reflected by the bias member at the first location. For example,
the system may include a splitter connected with the frequency
generator, spectrum analyzer, and/or the bias member such that each
of the frequency generator and spectrum analyzer can be coupled
with the bias member at the first location.
[0020] In other embodiments, however, the spectrum analyzer may be
coupled with the bias member at a second location that is distinct
or spaced apart from the first location. The second location may be
defined at any location along the bias member. For instance, in one
embodiment, the second location may be defined at an end of the
bias member that is opposite the first location, In such
embodiments, the radio frequency signal detected by the spectrum
analyzer may correspond with an insertion loss (S.sub.1,2) of the
bias member.
[0021] Example aspects of the present disclosure are directed to a
position sensor system for a vehicle pedal. For example, the system
may be configured to detect the position of a pedal member, such as
an accelerator pedal, brake pedal etc.
[0022] In some embodiments, the bias member may be coupled to each
of the first member and second member. For example, the bias member
may be configured to bias the second member away from the first
member.
[0023] In some embodiments, the second member may be pivotally
coupled to the first member.
[0024] In some embodiments, the bias member may be or include a
coil spring.
[0025] In some embodiments, the radio frequency circuity may
include a radio frequency generator electrically coupled with the
bias member at a first location of the bias member and configured
to apply the radio frequency signal to the bias member at the first
location.
[0026] In some embodiments, the radio frequency circuity may
include a spectrum analyzer electrically coupled with the bias
member at the first location of the bias member location and
configured to detect the radio frequency signal reflected by the
bias member at the first location.
[0027] In some embodiments, the system may include a splitter
having a first port, a second port, and a third port. The first
port may be connected to the bias member at the first location. The
second port may be connected to the frequency generator. The third
port may be connected to the spectrum analyzer such that each of
the frequency generator and spectrum analyzer are electrically
coupled with the bias member at the first location.
[0028] In sonic embodiments, the radio frequency circuity may
include a spectrum analyzer that is configured to detect an
amplitude of a reflected radio frequency signal reflected by the
bias member.
[0029] In some embodiments, the signal(s) indicative of the
position of the first member relative to the second member provided
by the radio frequency circuity may be positively correlated with
the amplitude detected by the spectrum analyzer.
[0030] In some embodiments, the radio frequency signal may include
a fixed amplitude sinusoidal signal. The fixed amplitude sinusoidal
signal may have a frequency that ranges from about 50 MHz to about
5 GHz, in some embodiments from about 100 MHz to about 4 GHz, in
some embodiments from about 150 MHz to about 2 GHz, and in some
embodiments from about 200 MHz to about 1 GHz.
[0031] Another example aspect of the present disclosure is directed
to a position sensor system for a vehicle pedal. The system may
include a base member, a pedal member movable relative to the base
member, and a bias member configured to bias the pedal member away
from the base member. The system may include radio frequency
circuitry configured to apply a radio frequency signal to the bias
member and provide one or more signals indicative of a position of
the base member relative to the pedal member based on a radio
frequency characteristic of the bias member.
[0032] In some embodiments, the pedal member may include an
accelerator pedal
[0033] In some embodiments, the bias member may be coupled to each
of the base member and pedal member.
[0034] In sonic embodiments, the pedal member may be pivotally
coupled to the base member.
[0035] In some embodiments, the bias member may include a coil
spring.
[0036] In some embodiments, the radio frequency circuity may
include a radio frequency generator electrically coupled with the
bias member at a first location of the bias member and configured
to apply the radio frequency signal to the bias member at the first
location.
[0037] In some embodiments, the radio frequency circuity may
include a spectrum analyzer electrically coupled with the bias
member at the first location of the bias member location and
configured to detect the radio frequency signal reflected by the
bias member at the first location.
[0038] In sonic embodiments, the system may include a. splitter
having a first port, a second port, and a third port. The first
port may be connected to the bias member at the first location. The
second port may be connected to the frequency generator. The third
port may be connected to the spectrum analyzer such that each of
the frequency generator and spectrum analyzer are electrically
coupled with the bias member at the first location.
[0039] In some embodiments, the radio frequency circuity may
include a spectrum analyzer configured to detect an amplitude of a
reflected radio frequency signal reflected by the bias member.
[0040] In some embodiments, the signal(s) indicative of the
position of the base member relative to the pedal member may be
positively correlated with the amplitude detected by the spectrum
analyzer.
[0041] In some embodiments, the radio frequency signal may include
a fixed amplitude sinusoidal signal. For example, the fixed
amplitude sinusoidal signal may have a frequency that ranges from
about 50 MHz to about 2 GHz.
[0042] Another example aspect of the present disclosure is directed
to a method for sensing a position of a first member relative to a
second member. The method may include applying a radio frequency
signal to a bias member that is configured to bias the second
member relative to the first member; detecting a radio frequency
characteristic of the bias member; and providing one or more
signals indicative of a position of the first member relative to
the second member based on the radio frequency characteristic of
the bias member.
[0043] FIG. 1 is a schematic drawing of a position sensor system
100 according to aspects of the present disclosure. The system 100
may include a first member 102 and a second member 104 movable
relative to the first member 102, for example as illustrated by
arrow 106. A bias member 108 may be configured to bias the second
member 104 relative to the first member 102. For example, bias
member 108 may be configured to bias the second member 104 towards
and/or away from the first member 102. The system 100 may include
radio frequency circuitry, such as a radiofrequency circuit 110.
The radiofrequency circuit 100 may be configured to apply a radio
frequency signal to the bias member 108 and provide one or more
signals indicative of a position of the first member 102 relative
to the second member 104 based on a radio frequency characteristic
of the bias member 108.
[0044] The bias member 108, first member 102, and second member 104
may have a variety of configurations. For example, the first member
102 may be directly coupled with the second member 104 (e.g.,
pivotally coupled). As another example, one or more additional
members may be coupled with the first member 102 and/or second
member 104 such that the first member 102 is articulated with
respect to the second member 104. As another example, the first
member 102 and/or second member 104 may be movable on a track or
may have an articulated configuration such that the first member
102 is movable relative to the second member 104. In some
embodiments, the first member 102 may be free of direct connection
with the second member. In other embodiments, the first member 102
may be coupled (e.g., pivotally coupled) to the second member 104.
The second member 104, however, may be movable relative to the
first member 102 in any suitable known configuration.
[0045] The bias member 108 may have a variety of configurations.
For example, the bias member 108 may be a spring having a helical
or conical configuration. In other embodiments, however, the bias
member 108 may be configured as a leaf spring (for examples as
described with reference to FIG. 3) or any other suitable resilient
member.
[0046] The radiofrequency circuit 110 may include a radio frequency
generator 112 electrically coupled with the bias member 108 at a
first location 114 of the bias member 108 and configured to apply
the radio frequency signal to the bias member 108 at the first
location 114. The radio frequency generator 112 may be configured
to apply the radio frequency signal to the bias member 108 at the
first location 114. The radio frequency signal may have a variety
of suitable attributes, such as frequency, amplitude, modulation,
etc. For example, the radio frequency signal may include a fixed
amplitude sinusoidal signal. The fixed amplitude sinusoidal signal
may have a frequency that ranges from about 50 MHz to about 2
GHz.
[0047] The characteristics of the radio frequency signal (e.g.,
amplitude, frequency, etc.) applied by the radio frequency
generator 112 may be selected based on characteristics of the
system 100. Example characteristics include size or resonant
frequencies of the bias member 108 and/or any surrounding
conductive structure.
[0048] The radiofrequency circuit 110 may include a spectrum
analyzer 116 that is electrically coupled with the bias member 108
at the first location 114 of the bias member 108 and configured to
detect the radio frequency signal reflected by the bias member 108
at the first location 114, for example as described in greater
detail below.
[0049] The system 100 may include a splitter 118 having a first
port 120, a second port 122, and a third port 124. The first port
120 of the splitter 118 may be connected to the bias member 108 at
the first location 114 (e.g., by a first cable 126). The second
port 122 of the splitter 118 may be connected to the frequency
generator 112 (e.g., by a second cable 128). The third port 124 may
be connected to the spectrum analyzer 116 (e.g., by a third cable
130) such that each of the frequency generator 112 and spectrum
analyzer 116 are electrically coupled with the bias member 108 at
the first location 114.
[0050] The first location 114 may be located at an end of the bias
member 108, for example as illustrated in FIG. 1. In other
embodiments, however, the first location 114 may be located at any
suitable location along the bias member 108, for example at a
middle location of the bias member 108. Alternatively, the
radiofrequency circuit 110 may be coupled with a conductive member
that is electrically coupled with the bias member 108. For example,
the first member 102 and/or second member 104 may be conductive and
electrically coupled with the bias member 108. The radiofrequency
circuit 110 may be coupled with the first member 102 and/or second
member 104 or otherwise located sufficiently near the bias member
108 to facilitate connection with the bias member 108.
[0051] The system 100 may include a conductive ground layer 132
arranged proximate the bias member 108. As used herein, "proximate"
can refer to a distance that is sufficiently small such that the
presence of the conductive ground layer 132 affects the radio
frequency characteristic of the bias member 108 by a measurable
amount. For example, the conductive ground layer 132 may be spaced
apart from the bias member 108 by a distance that is less than a
length 134 of the bias member 108. Alternatively, the conductive
ground layer 132 may be spaced apart from the bias member 108 by a
distance that is less than a width 136 of the bias member 108. The
conductive ground layer 132 may be coupled to the first member 102,
second member 104, or another suitable surrounding structure near
the bias member 108.
[0052] The spectrum analyzer 116 may configured to detect and/or
analyze the radio frequency characteristic of the bias member 108.
For example, the spectrum analyzer 116 may be configured to detect
and/or analyze radio frequency signals received via the third cable
130. Example radio frequency characteristics include frequency,
amplitude, DC bias, or other characteristics of the received radio
frequency signals. For instance, the radio frequency characteristic
may include an amplitude of a reflected radio frequency signal that
is reflected by the bias member 108. In this example, the reflected
radio frequency signal may correspond with a. return loss
(S.sub.11) of the bias member 108, The signals indicative of the
position of the first member 102 relative to the second member 104
may be positively correlated with the amplitude detected by the
spectrum analyzer 116,
[0053] In other embodiments, however, the spectrum analyzer 116 may
be coupled with the bias member 108 at a second location that is
distinct or spaced apart from the first location 114. The second
location may be defined at any location along the bias member 108.
For instance, in one embodiment, the second location may be defined
at an end 134 of the bias member 108 that is opposite the first
location 114. In such embodiments, the radio frequency signal
detected by the spectrum analyzer 116 may correspond with an
insertion loss (S.sub.1,7) of the bias member 108.
[0054] FIG. 2 is a schematic illustration of a position sensor
system 200 for a vehicle pedal. For example, the pedal member 202
may be or include an accelerator pedal for a vehicle. The system
200 may be generally configured as the system 100 described above
with respect to FIG. 1. For example, the system 200 may include a
base member 204 and a pedal member 202 movable relative to the base
member 204, for example as illustrated by arrow 206. The bias
member 208 may be coupled to each of the base member 204 and the
pedal member 202. The pedal member 202 may be pivotally coupled to
the base member 204, for example at a pivot location 203, Thus, the
bias member 208 may be configured to bias the pedal member 202 away
from the base member 204, for example towards an uncompressed
position.
[0055] The system 200 may include radio frequency circuitry, such
as a radio frequency circuit 210, for example as described with
reference to the radio frequency circuit 100 of FIG. 1. The radio
frequency circuit 210 may be configured to apply a radio frequency
signal to the bias member 208. The radio frequency circuit 210 may
be configured provide one or more signals indicative of the
position of the pedal member 202 relative to the base member 204
based on a radio frequency characteristic of the bias member 208.
For example, the radio frequency circuit 200 may include a radio
frequency generator 212 electrically coupled with the bias member
208 at a first location 214 of the bias member 208 and configured
to apply the radio frequency signal to the bias member 208 at the
first location 214. The radio frequency circuit 210 may include a
spectrum analyzer 216 electrically coupled with the bias member 208
at the first location 214 of the bias member 208 and configured to
detect the radio frequency signal reflected by the bias member 208
at the first location 214.
[0056] The system 200 may include a splitter 218, for example as
described above with reference to the splitter 118 of FIG. 1. The
splitter 218 may be connected with the frequency generator 212,
spectrum analyzer 216, and/or the bias member 208, for example as
described above with reference to the splitter 118 of FIG. 1.
[0057] The system 200 may include a conductive ground layer 232,
for example as described with reference to the conductive ground
layer 132 of FIG. 1. The conductive ground layer 232 may be
proximate the bias member 208 such that the conductive ground layer
232 affects the radio frequency characteristic of the bias member
208. The conductive ground layer 232 may be spaced apart from the
bias member 208 by a distance that is less than a length of the
bias member 208. Alternatively, the conductive ground layer 232 may
be spaced apart from the bias member 208 by a distance that is less
than a width of the bias member 208. The conductive ground layer
232 may be coupled to the base member 204 or pedal member 202, or
another suitable surrounding structure near the bias member
208.
[0058] FIG. 3 is a schematic drawing of another embodiment of a
position sensor system 300 employing a leaf spring bias member 308
according to aspects of the present disclosure. The position sensor
system 300 may generally be configured as the position sensor
system 100 described above with reference to FIG. 1 except that the
leaf spring bias member 308 may be employed. The reference numerals
of FIG. 3 may generally correspond with the reference numerals of
FIG. 1. As shown in FIG. 3, movement of the first member 302.
relative to the second member 304 may cause deflection of the leaf
spring bias member 308. The leaf spring bias member 308 may be
coupled with the first and second members 302, 304 in a cantilever
configuration. The first member 302 may be coupled at one end of
the leaf spring bias member 308. The second member 304 may be
coupled at an opposite end of the leaf spring bias member 308.
However, it should be understood that other suitable configurations
may be employed. For example, the first or second member 302, 304
may be coupled with the leaf spring bias member 308 at an
intermediate position (e.g., at a middle of the leaf spring bias
member 308). In such configurations, one or more of the ends of the
leaf spring bias member 308 may be mounted to supporting
structure.
[0059] The radiofrequency circuit 310 may be configured to apply a
radio frequency signal to the leaf spring bias member 308 and
provide one or more signals indicative of a position of the first
member 302 relative to the second member 304 based on a radio
frequency characteristic of the leaf spring bias member 308, for
example as described above with reference to FIGS. 1 and 2. It
should be understood that the bias member may have other
configurations.
[0060] FIG. 4 illustrates a flow diagram of an embodiment of a
method 400 for sensing a position of a first member relative to a
second member according to aspects of the present disclosure.
Although FIG. 3 depicts steps performed in a particular order for
purposes of illustration and discussion, the methods discussed
herein are not limited to any particular order or arrangement. One
skilled in the art, using the disclosures provided herein, will
appreciate that various steps of the methods disclosed herein can
be omitted, rearranged, combined, and/or adapted in various ways
without deviating from the scope of the present disclosure.
Moreover, the method 400 may be described herein with reference to
the sensor assemblies 100, 200, 300 described above with reference
to FIGS. 1 through 3. However, it should be appreciated that the
disclosed method 400 may be used for sensing a position of a first
member relative to a second member using a bias member having any
other suitable configuration.
[0061] The method 400 may include, at (402), applying a radio
frequency signal to a bias member that is configured to bias the
second member relative to the first member, for example as
described above with reference to the sensor assemblies 100, 200 of
FIGS. 1 and 2.
[0062] The method 400 may include, at (404), detecting a radio
frequency characteristic of the bias member. Example radio
frequency characteristics include frequency, amplitude, dc bias or
other characteristics of the received radio frequency signals. For
instance, the radio frequency characteristic may include an
amplitude of a reflected radio frequency signal that is reflected
by the bias member 108, for example as described above with
reference to the sensor assemblies 100, 200 of FIGS. I and 2.
[0063] The method 400 may include, at (406), providing one or more
signals indicative of a position of the first member relative to
the second member based on the radio frequency characteristic of
the bias member, for example as described above with reference to
the sensor assemblies 100, 200, 300 of FIGS. 1 through 3.
EXAMPLE
[0064] FIG. 5 illustrates experimental data collected for a pedal
sensor assembly that was fabricated similar to the pedal assembly
200 of FIG. 2. A radiofrequency signal having a frequency of about
656 MI-Iz was applied to the bias member at a first location. The
radiofrequency circuit detected the amplitude of a reflected
radiofrequency circuit at the first location. It was discovered
that the reflected radio signal (vertical axis) was approximately
linearly positively correlated with the compression of the bias
member (horizontal axis). In an uncompressed position (0%
compression), a sinusoidal signal having a frequency of about 656
MHz and an amplitude of about 1.19 mV was detected. In a fully
compressed position (100% compression), a sinusoidal signal having
a frequency of about 656 MHz and an amplitude of about 2.18 mV was
detected.
[0065] The radio frequency circuitry can include processing
circuitry configured to calculate the percent compression of the
bias member based on the detected amplitude of the reflected radio
frequency signal. For instance, the processing circuitry can employ
a lookup table, a correlating formula (e.g., empirically or
theoretically determined), and/or any other suitable means for
calculating the percent compression based on the amplitude of the
reflected radio frequency signal.
[0066] While the present subject matter has been described in
detail with respect to specific example embodiments thereof, it
will be appreciated that those skilled in the art, upon attaining
an understanding of the foregoing may readily produce alterations
to, variations of, and equivalents to such embodiments.
Accordingly, the scope of the present disclosure is by way of
example rather than by way of limitation, and the subject
disclosure does not preclude inclusion of such modifications,
variations and/or additions to the present subject matter as would
be readily apparent to one of ordinary skill in the art.
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