System for supervising access to restricted area, and method for controlling such a
system
The present invention relates to a system for supervising access to a restricted area,
5 including at least one obstacle that is mobile between a deployed configuration, in which said
obstacle extends across a passageway for the entry and/or exit totfrom said restricted area,
and a stowed configuration, in which said obstacle is removed from said passageway, the
system also comprising means for driving the obstacle between the deployed configuration
and the stowed configuration, a device for measuring the position of the obstacle, and a
10 module for controlling the drive means.
Such access supervision systems are known. They generally supervise access to a
pedestrian area, the inside of a building, or a public transportation system, and the obstacle
generally consists of a retractable bollard, a gate, or a door.
Access supervision systems must meet two competing requirements. On the one
15 hand, they must provide an effective barrier to the entry of fraudulent users inside the
restricted area, but must at the same time provide safety for users while preventing the
obstacle, after stowing thereof to free the passage for an authorized user, from colliding with
said user upon redeployment.
To meet this dual requirement, the known access supervision systems generally
20 comprise presence sensors suitable for detecting the presence of a user in the passageway
and identifying the position of the user in the passageway. The sensors are most often
suitable for identifying fraudulent users who wrongly try to cross the passageway.
However, these systems are not fully satisfactory. In fact, despite the use of presence
sensors, a user may not be detected when he is in the passageway, and the obstacle may
25 therefore collide with that user during redeployment. A fraudulent user may also manage to
make enough space to cross the passageway by forcing the obstacle.
One aim of the invention is therefore to propose an access supervision system
suitable for reinforcing user safety. Another aim is to propose an access supervision system
enabling more effective fraud prevention.
30 To that end, the invention relates to an access supervision system of the
aforementioned type, wherein the control module is suitable for comparing the measured
position of the obstacle at at least one moment in time with a theoretical position of the
obstacle at said moment in time, and for deriving a rule for controlling the drive means. -:k-3
2
According to pref2rred embodiments of the invention, the access supervision system
comprises one or more of the following features, considered alone or according to any
technically possible combination(s):
- the drive means are capable of exerting torque on the obstacle, and the deduced
control rule is capable of increasing said torque when the measured position differs from the
theoretical position;
- the deduced control rule is capable of immobilizing said obstacle when the
measured position differs from the theoretical position;
- the drive means are electric drive means and are capable of operating at a voltage
lower than 42 V; -
- the drive means are capable of exerting torque on the obstacle, and the drive
module is capable of deducing the control rule designed to stabilize or reduce said torque
when said torque exceeds a threshold torque;
- the value of the threshold torque is different depending on whether the difference
between the measured position and the theoretical position of the obstacle is positive or
negative; '
- the drive means comprise a synchronous electric motor;
- the electric motor is a brushless motor;
- the motor is adapted to be supplied with driving current for the motor and vibrating
current for the motor, the vibrating current being capable of causing the motor to produce a
frequency sound comprised between 2 kHz and 20 kHz when it is supplied with vibration
current;
- the measuring device is integrated into the drive means; and
- the control module is integrated into the drive means.
The invention alsowfaks to a method for controlling a system for supervising access
as defined above, said method comprising the following successive steps:
- stowing the obstacle,
- beginning deployment of the obstacle,
- measuring the position of the obstacle during deployment thereof,
- detecting a difference between the measured position of the obstacle and the
theoretical position of the obstacle, and
- acting on the obstacle.
According to preferred embodiments of the invention, the control method c~mpris&,,-~
one or more of the following features, considered alone or according to any technically
possible combination(s):
- the action is-an'immobilization of the obstacle;
- the drive means are adapted to exert a torque on the obstacle, and the action is an
increase in said torque.
Other features and advantages will appear upon reading the following description,
provided solely as an example and done in reference to the appended drawings, in which:
- Figure 1 is a diagrammatic top view of an access supervision system according to
the invention,
- Figure 2 is a diagrammatic cross-sectional view of a motor integrated into the
access supervision system of Figure 1,
- Figure 3 is-a diagram of a supervising module for the electricity of a motor
integrated into the access supervision system of Figure 1,
- Figure 4 is a block diagram illustrating a first method implemented by a control
module of the supervising module of Figure 4, and
, , - Figure 5 is a block diagram illustrating a second method implemented by the
control module of the supervising module of Figure 4.
The access supervision system 10, shown in Figure 1, is a gate for supervising
access to a restricted area. Said restricted area is typically a building or a public
transportation system.
The access supervision system 10 includes a housing 12 defining a passageway 14,
an obstacle 16, suitable for obstructing the passageway 14, and means 18 for driving the
obstacle 16.
The housing 12 comprises a motor compartment 20 and, optionally, a low wall 22.
The motor compartment 20 defines an edge 24 of the passageway 14. The low wall 22
defines an edge 26 of the passageway 14, opposite the edge 24.
The passageway 14 constitutes an entry and exit passageway to and from the
restricted area. It extends between the motor compartment 20 and the low wall 22 of said
housing 12. It defines a circulation axis C to enter and exit said restricted area.
The passageway 14 emerges by an outer end 27A at the outside of the restricted
area. Its opposite end 27B1 here called "inner end," emerges inside the restricted area.
The obstacle 16 is mobile between a deployed configuration, in which it extends
through the passageway 14, and a stowed configuration, in which it is freed from the
passageway 14. In the deployed configuration, the obstacle 16 obstructs the passageway 14
and opposes crossing of the passageway 14 by a user. In the stowed configuration, the-?
obstacle 16 frees the passageway 14 and allows crossing of the passageway 14 by a user.
In the illustrared*cxample, the obstacle 16 is formed by a door 28. The door 28 is
mounted pivotably on the motor compartment 20 around a vertical axis Z perpendicular to
the circulation axis C. In the deployed configuration, the door 28 extends substantially
perpendicular to the circulation axis C. In the retracted configuration, the door 28 extends
substantially parallel to the axis C, along the edge 24.
Alternatively, the frame 12 comprises a second motor compartment 20 replacing the
low wall 22. The obstacle 16 then comprises two doors 28, each door 28 being articulated
around a vertical axis on a respective motor compartment 20. In the deployed configuration
of the obstacle 16, each door 28 extends perpendicular to the circulation axis C. In the
retracted configuration of the obstacle 16, each door 28 extends along an edge 24, 26 of the
passageway 14.
The drive means 18 are suitable for driving the obstacle 16 between the deployed
and stowed positions thereof. To that end, the drive means 18 are suitable for pivoting the
door 28 around the vertical axis C.
The drive means 18 comprise a motor 30 and a device 32 for coupling the motor 30
to the obstacle 16.
The motor 30 is an electric motor, preferably synchronous, typically a brushless
electric motor. It is mounted in the motor compartment 20. It is shown in Figure 2.
In reference to Figure 2, the motor 30 comprises a rotor 34 and a stator 36.
The stator 36 is secured to the frame 12. It defines a substantially cylindrical cavity 38
for receiving the rotor 34.
The rotor 34 is cylindrical and extends inside the cavity 38. It is mounted rotating
relative to the stator 36. To that end, ball bearings (not shown) are mounted between the
rotor 34 and the stator 36 at the longitudinal ends of the rotor 34.
The rotor 34 is mechanically connected to the obstacle 16 such that it is rotatable
around its axis jointly with the movement of the obstacle 16.
The rotor 34 comprises at least one permanent magnet 40, preferably several
permanent magnets 40, the or each permanent magnet 40 comprising a north magnetic pole
42 and a south magnetic pole 44. The permanent magnet 40 is made from a ferromagnetic
material, typically ferrite or samarium cobalt. In the illustrated example, the rotor 34
comprises a single permanent magnet 40.
The stator 36 also comprises a plurality of solenoids 46A, 466, 46C regularly
distributed at the periphery of the cavity 38. In the illustrated example, there are thre-&-7
solenoids 46A, 46B, 46C that define sectors between them of substantially 21~13 radians
along a plane perpendicular to the extension direction of the cavity 38. More generally, when .
5
the stator 36 ~ompfise~naum ber n of solenoids 46A, 46B, 46C, the latter then delimit
sectors between them measuring substantially 2rrln radians in a plane perpendicular to the
extension direction of the cavity 38.
Each solenoid 46A, 46B, 4 6 i~s c apable of being traveled by an electric supply
current of the motor 30, so as to induce a magnetic field inside the cavity 38. Each solenoid
46A, 466, 46C is capable of behaving like a north magnetic pole when it is traveled by the
electric supply current I.
Thus, when a solenoid 46A is traveled by the supply current I, the magnetic field
induced by said solenoid 46A exerts a force on the magnet 40. The magnet 40 then tends to
align with the induced magnetic field. If the magnet 40 is not aligned with said magnetic field,
a motor torque is exerted on the rotor 34, rotating the latter. If the magnet 40 is aligned with
the induced magnetic field, then a resistive torque is exerted on the rotor 34, opposing the
rotation of the rotor 34 around its axis.
When the obstacle 16 is immobile, the solenoids 46A, 466, 46C are capable of
inducing a fixed magnetic field in the cavity 38 applying a resistive torque on the rotor 34.
This resistbe torque opposes the rotation of the rotor 34 around its axis.
When the obstacle 16 is in motion, the solenoids 46A, 468, 46C can induce a rotating
magnetic field inside the cavity 38, so as to apply a motor torque on the rotor 34. To that end,
the solenoids 46A, 46B, 46C are in turn supplied with current such that the magnet 40 is
never aligned with the magnetic field induced by the solenoids 46A, 469,46C.
The motor 30 also comprises a case 48 (Figure 1) surrounding the rotor 34 and the
stator 36. The case 48 defines the outer surface of the motor 30.
The motor and resistive torques applied on the rotor 34 are transmitted to the
obstacle 16 by means of the coupling device 32.
The coupling device 32 typically comprises a planetary reduction gear (not shown)
capable of increasing the torque exerted by the motor 30 on the obstacle 16.
Returning to Figure 1, the access supervision system 10 also comprises means 50 for
controlling the drive means 18. These control means 50 comprise a module 52 for
supervising the electrical power supply of the motor 30, a circulation authorization system 54,
a device 56 for detecting fraud, and a device 58 for measuring the position of the obstacle
16.
The circulation authorization system 54 is installed in the motor compartment 20. It
comprises a central unit 80 and document readers 82. --aY3
Each reader 82 is capable of communicating with a travel document belonging to a
user, typically a card. Each reader 82 is for example a contactless reader and is capable of
exchanging data with-the travel document using a magnetic field, when the document is at a
sufficient distance from the reader 82. The reader 82 is capable of transferring the
exchanged data to the central unit 80.
One of the readers 82 is positioned near the outer end 27A of the passageway 14
5 and another reader 82 is positioned near the inner end 27B of the passageway 14.
The central unit 80 is capable of determining whether the user owning the travel
document is authorized to use the passageway 14. This determination is typically made by
reading a contract number on the document and verifying the accreditations granted to that
contract. Other alternatives are possible and, being known by those skilled in the art, will not
10 be described here. -
The central unit 80 is capable of supervising the stowage of the obstacle 16 when the
user is authorized to use the passageway 14. To that end, the central unit 80 is capable of
emitting a circulation authorization notification A,, to the supervising module 52.
The central unit 80 is also capable of not commanding stowage of the obstacle 16
15 when the user is not authorized to use the passageway 14.
The fraud detection device 56 comprises presence sensors 84A, 848, to detect the
presence of a user in the passageway 14, and a computer 86.
A first presence sensor 84A is capable of detecting the presence of the user between
the obstacle 16 and the outer end 27A of the passageway 14. A second sensor 848 is
20 capable of detecting the presence of the user between the obstacle 16 and the inner end
27B of the passageway 14.
Each presence sensor MA, 84B is capable of emitting a user detection notification to
a computer 86 when the presence of a user in the passageway 14 is detected by the sensor
84A, 84B.
k 25 The computer 86 is capable of detecting a fraud attempt from user detection
notifications communicated by the sensors 84A, 84B. The computer 86 is for example
I capable of detecting a fraud attempt when it receives a user detection notification from one of
I
;
the sensors MA, 84B whereas no circulation authorization notification has been emitted by
I
I the central unit 80, or when the sensors 84A, 84B detect the simultaneous presence of two
I 30 users in the passageway 14. I
The computer 86 is also capable of emitting a fraud attempt detection notification FO
to the supervising module 52 when it detects a fraud attempt.
The measuring device 58 comprises a sensor 88A (Figure 2) sensing the angular,-?
position of the rotor 34 and a system 88B for detecting the position of the obstacle 16 from
35 the angular position of the rotor 34.
7
The sensor 88A i3 secured to the stator 36 of the motor 30. It is capable of measuring
the angle between the position of the rotor 34 around its axis at a moment and a reference
position of the rotor 34 around its axis.
The sensor 88A is typically capable of measuring the magnetic field prevailing inside
the cavity 38 to deduce the angular position of the rotor 34 therefrom. The sensor 88A is
typically a Hall effect sensor.
The calculation system 88B is capable of deducing the measured position of the
obstacle 16 from the angular position of the rotor 34 measured by the sensor 88A. In fact,
since the rotor 34 is rotatable around its axis jointly with the movement of the obstacle 16,
there is a bijective application connecting the angular position of the rotor 34 to the position
of the obstacle 16 in the passageway 14. This application is implemented in the calculation
system 88.
The measured position-of the obstacle 16 is comprised between -90" and +90°. The -
90" and +90° positions correspond to stowed positions of the obstacle 16. In the +90°
position, the obstacle 16 extends along the edge 24 of the passageway 14, toward the outer
end 27A of the passageway 14. In the -90" position, the obstacle 16 extends along the edge
24 of the passageway 14, toward the inner end 27B of the passageway 14. The 0" position
corresponds to the deployed position of the obstacle 16.
The measuring device 58 is capable of transmitting the measured position P, of the
obstacle 16 to the supervising module 52.
The supervising module 52 is electrically connected on the one hand to an electricity
line 59, and on the other hand to the motor 30. The supervising module 52 is capable of
selectively connecting each solenoid 46A, 46B, 46C of the motor 30 to the supply line 59.
The supervising module 52 is thus capable of supervising the power supply of each solenoid
46A, 46B, 46C. -
The supply line 59 is capable of delivering a DC driving current of the motor 30.
Preferably, the delivered DC current has a voltage below 42 V, said to be very low voltage.
In reference to Figure 3, the supervising module 52 comprises a plurality of electrical
lines 60A, 60B, 60C supplying the motor 30 with current. The number of electrical lines 60A,
60B, 60C is equal to the number of solenoids 46A, 46B, 46C.
Each line 60A, 60B, 60C, respectively, connects the power supply line 59 to one of
the solenoids 46A, 46B, 46C, respectively. Each line 60A, 60B, 60C, respectively, is
equipped with a switch 62A, 62B, 62C, respectively. Each line 60A, 60B, 60C is alsk-3
equipped with a device 63 for measuring the intensity of the current circulating in the line
60A, 60B, 60C.
Each switch 62A:'62B, 62C is capable of selectively blocking the circulation of an
electrical current inside the corresponding line 60A, 60B, 60C, when it is switched into a socalled
off configuration, or allowing the circulation of such an electrical current when it is
switched in a so-called on configuration.
Depending on the switching frequency of each switch 62A, 628, 62C, the average
supply current received by the associated solenoid 46A, 46B, 46C varies. It is thus possible
to vary the intensity df the magnetic field induced by each solenoid 46A, 46B, 46C and, from
there, to vary the torque exerted by the drive means 18 on the obstacle 16. It is also possible
to vary the orientation of the magnetic field induced inside the cavity 38, so as to generate a
rotating magnetic field jraside the cavity 38 to move the obstacle 16 between its deployed and
stowed positions.
The supervising module 52 also comprises an AC current source 64. This source 64
is connected by electrical connecting lines 66 to each of the supply lines 60A, 60B, 60C. The
line 66 is equipped with a switch 68, to selectively disconnect each solenoid 46A, 466, 46C
from the source 64 when the switch 68 is in the off configuration, or to couple each solenoid
46A, 46B, 46C to the source 64 when the switch 68 is in the on configuration.
The source 64 is capable of generating an AC current for vibrating the motor 30 such
that, when injected into the solenoids 46A, 468, 46C, said current causes the motor 30 to
produce a frequency sound comprised between 2 kHz and 20 kHz.
The supervising module 52 also comprises a device 69 for evaluating the torque C
exerted by the drive means 18 on the obstacle 16, from the intensities measured by the
devices 63. The manner in which this type of evaluation is done is known by those skilled in
the art and will not be described here.
Lastly, the supervising module 52 comprises a control module 70 for the drive means
18. This module 70 is capable of deducing, at each moment t, a control rule LC of the drive
means 18 from a plurality of parameters. These parameters comprise:
- fraud attempt detection notifications Fo emitted by the detection device 56,
- circulation authorization notifications A. emitted by the circulation authorization
module 54,
- the position P, of the obstacle 16 measured by the measuring device 58 at a
moment t-bt, preceding the moment t, and
- a theoretical position Pth of the obstacle 16 at moment t-bt, stored in a memory 72
of the control module 70. -23-
Alternatively, the control module 70 is capable of deducing the control rule LC at least
at one moment.
means 18 on the obstacle 16 and a movement speed reference of the obstacle 16. The
control module 70 is capable of controlling the switching of the switches 62A, 628, 62C
according to the control rule LC.
5 The control rule LC is typically a pulse width modulation (PWM) control rule.
The memory 72 also stores a default predetermined control rule LCo and a plurality of
special predetermined control rules LCsl, LCs2, LCs3, LCs4.
The default predetermined control rule LCo is adapted so that, under normal operating
conditions of the access supervision system 10, the actual position of the obstacle 16
10 corresponds to the the~reticalp osition Pw. "Normal operating conditions" means that, with
the exception of any torques due to friction of the obstacle 16 against the frame 12 or gravity,
no torque other than that exerted by the drive means 18 is applied to the obstacle 16.
A first special predetermined control rule LCsl is adapted to immobilize the obstacle
16 irrespective of its position, without varying the value of the torque C exerted by the drive
15 means 18 on the obstacle 16.
A second special predetermined control rule LCs2 is adapted to increase the torque C
applied by the drive means 18 on the obstacle 16 beyond that provided by the default
predetermined control rule LCo.
A third special predetermined control rule LCs3 is adapted to stabilize the torque C
20 applied by the drive means 18 on the obstacle 16.
A fourth special predetermined control rule LCs4 is adapted to reduce the torque C
applied by the drive means 18 on the obstacle 16.
In reference to Figures 4 and 5, the control module 70 is further adapted to compare,
at each moment t, the measured position P, of the obstacle 16 at a moment t-bt immediately
25 preceding the moment t, with the theoretical position Pa of the obstacle 16 at that moment t- - - -
bt, and to deduce the control rule LC therefrom. Thus, when the measured position P, of the
obstacle 16 at moment t-bt corresponds to the theoretical position Pw of the obstacle at
moment t-bt, the module 70 is capable of deducing the control rule LC as being equal to the
default predetermined control rule LCo. When, however, the measured position P, of the
30 obstacle 16 at moment t-bt differs from the theoretical position Pw of the obstacle at moment
t-bt, the module 70 is adapted to deduce the control rule LC as being equal to one of the
special predetermined control rules LCs1, LCs2, LCs3, LCs4.
As shown in Figure 4, the control module 70 is capable of deducing the control ruI&-J
LC as being equal to the first special predetermined control rule LCsl when:
- the meas5reifi position P, of the obstacle 16 at moment t-bt differs from the
theoretical position Pth of the obstacle 16 at moment t-bt, and
- the module 70 does not receive a fraud attempt detection notification Fo.
The control module 70 is capable of deducing the control rule LC as being equal to
5 the second special predetermined control rule LCs2 when:
- the measured position P, of the obstacle 16 at moment t-bt differs from the
theoretical position Pth of the obstacle 16 at moment t-bt, and
- the module 70 receives a fraud attempt detection notification Fo.
As shown in Figure 5, the control module 70 is capable of producing the control rule
10 LC as being equal to the third special predetermined control rule LCs3 when:
- the torque C exerted by the drive means 18 on the obstacle 16 exceeds a
threshold to r,q,uC, e and
- the module 70 receives a fraud attempt detection notification Fo.
The control module 70 is capable of deducing the control rule LC as being equal to
15 the fourth special predetermined control rule LCs4 when:
- 'the torque C exerted by the drive means 18 on the obstacle 16 exceeds a
threshold to r,q,C,ue and
- the module 70 does not receive a fraud attempt detection notification Fo.
Still in light of Figure 5, the control module 70 is also capable of determining whether
20 the difference between the measured P, and theoretical Pth positions of the obstacle 16 is
positive or negative. Said difference is considered to be the angle formed between the
theoretical position of the obstacle 16 and the measured position of the obstacle 16, from the
theoretical position toward the measured position. Thus, when the measured position P,
indicates that the obstacle 16 is closer to the outer end 27A of the passageway 14 than it
25 would be if it were in its theoretical position Pth, the difference is positive. Likewise, when the
measured position P, indicates that the obstacle 16 is closer to the inner end 27B of the
passageway 14 than it would be if it were in its theoretical position Pth, the difference is
negative.
The control module 70 is adapted so that the value of the threshold torq u,C,e is
30 different depending on whether the difference between the measured P, and theoretical Pu,
positions of the obstacle 16 is positive or negative. In particular, the control module 70 is
adapted so that the value of the threshold torque C,,, is higher when the difference between
the measured P, and theoretical Pth positions is negative than when said difference ik-J
positive.
11
Thus, it is easierqor a user to exit the restricted area by forcing the obstacle 16 than to enter said area by forcing the obstacle 16. The system 10 for supervising access thus
constitutes an effective barrier against fraud, while facilitating the evacuation of users present
inside the restricted area in case of emergency, for example in case of fire.
Returning to Figure 4, the control module 70 is also adapted to switch the switch 68
into the on configuration when:
- the measured position P, of the obstacle 16 at moment t-bt differs from the
theoretical position of the obstacle at moment t-bt, and
- the module 70 receives a fraud attempt detection notification Fo.
Thus, a fraudulent user wishing to cross the passageway 14 by forcing the obstacle
16 would trigger an alarm.
It will be noted that the supervising module 52, the measuring device 58 and the
computer 86 of the detection device 56 are preferably integrated into the motor 30. They are
in particular housed inside the case 48. Thus, the access supervision system 10 is easier to
manufacture and the production costs of the access supervision system 10 are reduced.
A control method for the drive means 18, implemented by the control module 70, will
now be described.
In the initial state, the obstacle 16 is in the deployed position. The control module 70
commands the switches 62A, 62B, 62C according to the default predetermined control rule
LCo, such that the drive means 18 exert a resistive torque C on the obstacle 16 keeping it
immobile.
A user approaches one end 27A, 276 of the passageway 14. He shows his card to a
reader 82, and the central unit 80 determines whether the user is authorized to cross the
passageway 14.
The control module 70 then receives a circulation authorization notification &, emitted
by the module 54. According to the default predetermined control rule LC, it commands the
stowage of the obstacle 16 then, after a predetermined period of time, it commands the
redeployment of the obstacle 16.
If the user approached the outer end 27A of the passageway 14, the supervising
module 70 commands the drive means 18 so as to stow the obstacle 16 toward the inner end
27B. If the user approached the inner end 27B of the passageway 14, the module 70
commands the drive means 18 so as to stow the obstacle 16 toward the outer end 27A.
At the same time, the position P, of the obstacle 16 is measured using the measurin&--7
device 58. This information is sent to the control module 70 which, at each moment,
compares it with the the6retical position Pth that the obstacle 16 is supposed to occupy at that
same moment.
Once the control module 70 detects a difference between the measured position P,
and the theoretical position Pw, it modifies the control rule LC of the drive means 18.
At the same time, the control module 70 determines the sign of the difference
between the measured P, and theoretical Pth positions of the obstacle 16. If that difference is
positive, it sets a threshold torqu e,,C, , exerted by the drive means 18 on the obstacle 16,
equal to a first value C,. If the difference is negative, it sets the threshold torq u,,eC, equal to
a second value C2, greater than C,.
If the detection-device 56 does not emit a fraud attempt detection notification Fo, the
control module 70 deduces the control rule LC as being equal to the first special control rule
LCsl. The control of the switches 62A, 626, 62C is then modified so as to stop the rotation of
the magnetic field within the cavity 38. The torque C applied by the drive means 18 on the
obstacle 16 is kept constant.
If the detection device 56 emits a fraud attempt detection notification Fo, the control
module 70 deduces the control rule LC as being equal to the second special control rule
LCs2. The switching frequency of the switches 62A, 62B, 62C is then increased.
Furthermore, the control module 70 commands the switching of the switch 68 into the on
configuration. The AC current generated by the source 64 is then injected into the solenoids
46A, 46B, 46C. Under the effect of that current, the motor 30 produces a sound with a
frequency comprised between 2 kHz and 20 kHz.
If, however, the torque C exerted by the drive means 18 on the obstacle 16 exceeds
the threshold torque C, then the control module 70 again modifies the control rule LC, so
as to stabilize the torque C exerted by the drive means 18. Said torque C then no longer
increases.
In the example described above, the access supervision system 10 has been
described as comprising a fraud detectron device. Alternatively, the access supervision
system 10 does not comprise such a device, and the module 70 is then programmed to carry
out only one of the first and second special control rules LCsl, LCs2, and only one of the third
and fourth special control rules LCs3, LCs4.
Owing to the invention, the safety of the access supervision system 10 is
strengthened. The obstacle 16 is in fact less likely to collide violently with the user.
Furthermore, the evacuation of the restricted area in case of emergency is made easier. - 3 - 3
Furthermore, the access supervision system 10 makes it possible to combat fraud
more effectively. In fact, the increasing torque exerted by the drive means 18 on the obstacle
16 makes it possible tomeffectively oppose-the force applied by a fraudulent user on the
obstacle.
Additionally, using a brushless synchronous electric motor allows particularly easy
control of the drive means.
5 Furthermore, the supply current of the drive means 18 is a very low-voltage current,
which makes it possible to limit electrical risks for maintenance workers.
Lastly, the generation of a sound by the motor makes it possible to provide an alert
that a fraud attempt is in progress.

1.- A system (10) for supervising access to a restricted area, including at least one
obstacle (16) that is mobile between a deployed configuration, in which said obstacle
extends across a passageway (14) for the entry and/or exit tolfrom said restricted area, and
a stowed configuration, in which said obstacle is removed from said passageway (14), the
system (1 0) also comprising:
- means (18) for driving the obstacle (16) between the deployed configuration and the
stowed configuration, adapted to exert torque (C) on the obstacle (16),
- a device (58) for measuring the position of the obstacle (16),
- a circulation wthorization system (54), installed in a motor compartment (20) of the
access supervision system (lo), and comprising a central unit (80) and document readers
(82), each document reader (82) being adapted to communicate with a travel document of a
user, and the central unit (80) being adapted to determine whether the user owning the travel
document is authorized to use the passageway (14), and
- a module (70) for controlling the drive means (1 8),
characterized in that the control module (70) is suitable for comparing the measured
position (P,) of the obstacle (16) at at least one moment in time (t-at) with a theoretical
position (Pth) of the obstacle (16) at said moment in time, and for deriving a rule (LC) for
controlling the drive means (la), said control rule (LC) being designed to stabilize or reduce
the torque (C) exerted by the drive means (18) when that torque (C) exceeds a threshold
torque (C,), the value of the threshold torque (C,,,) being different depending on whether
the difference between the measured position (P,) and the theoretical position (Pth) of the
obstacle (16) is positive or negative.
2.- The access supervision system (1 0) according to claim 1, characterized in that the
deduced control rule (LC) is adapted to increase the torque (C) exerted by the drive means
(1 8) when the measured position (P,) differs from the theoretical position (Pth).
3.- The access supervision system (10) according to claim 1, characterized in that the
deduced control rule (LC) is capable of immobilizing said obstacle (16) when the measured
position (P,) differs from the theoretical position (Pth).
4.- The access supervision system (1 0) according to any one of the preceding claims,
characterized in that the drive means (18) are electric drive means and are capable of
operating at a voltage lower than 42 V.
5.- The access supervision system (1 0) according to any one of the preceding claim-ew-7
characterized in that it comprises a fraud detection device (56).
-9" -_ ._ cey4 6.- The access supervision system (1 0) according to any one of the preceding claims,
characterized in that the motor compartment (20) defines an edge (24) of the passageway
(14).
7.- The access supervision system (10) according to any one of the preceding claims,
5 characterized in that the drive means (18) comprise a synchronous electric motor (30).
8.- The access supervision system (10) according to claim 7, characterized in that the
electric motor (30) is a brushless motor.
I 9.- The access supervision system (10) according to claim 7 or 8, characterized in
I that the motor (30) is adapted to be supplied with driving current for the motor (30) and
I 10 vibrating current for themotor (30), the vibrating current being capable of causing the motor
(30) to produce a frequency sound comprised between 2 kHz and 20 kHz when it is supplied
with vibration current.
10.- T~B-access superusion system (10) according to any one of the preceding
claims, characterized in that the measuring device (58) is integrated into the drive means
15 (18).
11 .-' The access supervision system (1 0) according to any one of the preceding
claims, characterized in that the control module (70) is integrated into the drive means (1 8).
12.- A method for controlling the access supervision system (10) according to any
one of the preceding claims, said method comprising the following successive steps:
20 - stowing the obstacle (16), . I
- beginning deployment of the obstacle (16),
- measuring the position of the obstacle (16) during deployment thereof,
- detecting a difference between the measured position (P,) of the obstacle (16) and
-
the theoretical position (Pth) of the obstacle (16), and
- 25 ' - acting on the obstacle (16). --. . - .
13.- The control method according' to claim 12, characterized in that the action is an
immobilization of the obstacle (16).
14.- The control method according to claim 12, characterized in that the drive means
(18) are adapted to exelt a torque (C) on the obstacle (16), and the action is an increar in
30 said torque (C).
__ _ .__.
Dated this November 29,2013 -1 _
ATTORNEY FOR THE APPLIC/LEIT[S]