JP4265983B2 - Obstacle detection device for automatic door control system - Google Patents

Description

  The present invention relates to a technical improvement of an obstacle detection device of an automatic door control system installed in, for example, an automobile, and more particularly to a detection of a closed obstacle using a capacitive proximity sensor.

  For example, when an automobile door is converted to an automatic door, an object such as a person or a baggage is likely to be caught by the door during the door closing operation, similar to an automatic door at the entrance of a general building. It is desirable to equip an automatic door control system that interrupts the door closing operation. In the case of an automobile door, the environment / situation is different from that of an automatic door at the entrance and exit of a general building. Therefore, the technology of a general automatic door control system cannot be applied as it is. One typical prior art employs a configuration in which a pressure sensor is installed on an opening end surface of a door and an obstacle is detected by contact pressing. In this system, for example, when a human body hits a moving door, there arises a problem that a person falls due to an impact.

  In order to solve the above-mentioned elementary problems using a pressure sensor, it is possible to adopt a configuration using a capacitive proximity sensor as an obstacle detection device that detects a person or a baggage present in a door opening. it can. In this case, the capacitive proximity sensor is disposed so that the space opened and closed by the door is an obstacle detection target area (discrimination threshold), and the door end surface and an opening member that contacts the door (in the case of an automobile) Detects electrostatically an object interposed between the center pillar and the adjacent door end face.

  In other words, the capacitive proximity sensor electrostatically detects the presence of an object within the front-side discrimination threshold that contacts the opening member when the door is closed, so of course immediately before the door is completely closed. Since the door end surface approaches the opening member, the member enters the discrimination threshold of the proximity sensor, and a detection signal is output from the proximity sensor. If the door closing drive is stopped in response to this detection signal, the door may not be completely closed.

  An object of the present invention is to solve these problems and to realize an obstacle detection device for a higher performance automatic door control system.

The obstacle detection device of the automatic door control system according to the present invention is specified by the following items (1) to (7).
(1) Obstacle detection of an automatic door control system that includes a capacitive proximity sensor, a shielding electrode, an electric field strength detection circuit, and a shielding voltage generation circuit, and detects the presence of an obstacle in the space where the door is closed. Being a device,
(2) The capacitance type proximity sensor is attached to one member of the door member and the opening member that forms an opening space that expands and contracts as the door is opened and closed with the discrimination threshold facing the opening space, Including a sensor circuit and a probe electrode;
(3) The sensor circuit detects whether there is an obstacle in the vicinity of the discrimination threshold based on the grounding capacitance formed by the sensor electrode,
(4) The probe electrode is disposed in the vicinity of the sensor electrode,
(5) The electric field strength detection circuit detects the electric field strength sensed by the probe electrode,
(6) The shielding electrode is attached to the other member of the door member and the opening member, and covers the portion close to the capacitive proximity sensor when the door is closed from the capacitive proximity sensor side,
(7) The shielding voltage generation circuit applies a voltage generated based on the output level of the electric field strength detection circuit to the shielding electrode, and variably controls the applied voltage so that the output level of the electric field strength detection circuit is maintained at a set value. To do,

Based on the above configuration, the present invention can be implemented by appropriately adding the following technical items (A) to (E).
(A) The set value in the shielding voltage generation circuit is set based on the output level of the electric field strength detection circuit in the door open state,
(B) The capacitive proximity sensor includes a reference electrode, the reference electrode is arranged so as to be hidden behind the sensor electrode when viewed from the opening space, and the sensor circuit has a capacitance formed by the sensor electrode. And outputting a detection signal based on the difference between the capacitance formed by the reference electrode and
(C) The sensor electrode is configured as a movable electrode that is displaced by contact pressing from the opening space side and contacts the reference electrode, and the sensor circuit includes a circuit that detects contact between the sensor electrode and the reference electrode.
(D) The sensor electrode is configured as a movable electrode that is driven to be displaced by contact pressing from the opening space side and approaches the reference electrode, and the sensor circuit includes a capacitance formed by the sensor electrode and a capacitance formed by the reference electrode. Including a circuit that detects the approach of both electrodes based on capacitance;
(E) the capacitive proximity sensor includes a cushioning actuator disposed on the front side of the sensor electrode;

  For example, in an obstacle detection device of an automatic door control system installed in an automobile, even if a very small object such as a human finger is present immediately before the center pillar, the capacitive proximity sensor is not It is possible to accurately detect a small object (closed obstacle) existing just before the center pillar, ignoring the presence of the pillar. That is, even when the door part approaches the opening part, the closed obstacle can be reliably detected, and an obstacle detection apparatus for a higher-performance automatic door control system is realized.

  FIG. 1 is a conceptual diagram illustrating an obstacle detection apparatus according to an embodiment of the present invention. The apparatus shown in the figure includes a capacitive proximity sensor 40, a shielding electrode 15, an electric field strength detection circuit 31, and a shielding voltage generation circuit 32, and there is an obstacle in the opening space 10 that opens and closes the door. The obstacle detection device of the automatic door control system that detects

  The capacitive proximity sensor 40 includes a sensor electrode 11, a probe electrode 13, and a sensor circuit 20. The proximity sensor 40 is attached such that the discrimination threshold (detection target area) faces the opening space 10 that expands and contracts as the door is opened and closed. The opening space 10 is formed by a door member such as a slide door and an opening member such as a center pillar, and is enlarged or reduced by opening / closing the door member.

  In this embodiment, the sensor electrode 11 is attached to the door member side. The sensor electrode 11 forms a ground capacitance (capacitance) Ca. This capacitance Ca changes depending on the presence or absence of an obstacle (detected body) in the vicinity of the discrimination threshold. The sensor circuit 20 detects whether an obstacle exists in the vicinity of the discrimination threshold based on the grounding capacitance Ca formed by the sensor electrode 11. The sensor electrode 11 may be attached to the opening member side.

  A probe electrode 13 is disposed in the vicinity of the sensor electrode 11. The sensor electrode 11 and the probe electrode 13 are electrically independent electrodes, but are structurally integrated (not shown). In the illustrated example, the probe electrode 13 is disposed at one end of the sensor electrode 11. However, the probe electrode 13 may be appropriately disposed at the middle or both ends of the sensor electrode 11 as necessary.

  The shielding electrode 15 is attached to the opening member side, and covers a portion (opening member side portion 16) that comes close to the capacitive proximity sensor 40 when the door is closed from the sensor 40 side. The probe electrode 13 senses an electric field acting in the vicinity of the sensor electrode 11. The electric field strength detection circuit 31 detects the strength of the electric field sensed by the probe electrode 13. The shielding voltage generation circuit 32 applies a voltage generated based on the output level of the electric field strength detection circuit 31 to the shielding electrode 15 and also applies the applied voltage so that the output level of the electric field strength detection circuit 31 is maintained at a set value. Is variably controlled.

Next, the operation will be described.
A voltage VC for capacitance measurement is applied to the sensor electrode 11, thereby forming an electric field in the opening space 10. If a closed obstacle exists in this electric field, a change occurs in the grounding capacitance Ca of the sensor electrode 11. The sensor circuit 20 detects the changing capacitance Ca and converts the voltage. The presence or absence of an obstacle can be determined based on the output Vca of the sensor circuit 20.

  At this time, the opening member side portion 16 positioned in the capacitance sensing direction of the sensor electrode 11 is covered with the shielding electrode 15, and the potential of the shielding electrode 15 is set to the voltage (shielding voltage) VS applied from the shielding voltage generation circuit 32. By setting the potential, the opening member side portion 16 can be electrostatically shielded from the sensor electrode 11, and the opening member side portion 16 can be prevented from becoming a hindrance to detection (noise factor).

  As shown in FIG. 2A, the shielding voltage VS is set to a voltage such that the shielding electrode 15 has the same potential as or close to the sensor electrode 11. The capacitance formed can be canceled out or reduced equivalently. By such active shielding, the shielding electrode 15 is effectively invisible from the sensor electrode 11, and the capacitance change of the sensor electrode 11 caused by the closed obstacle that is the detection target can be selectively detected with high sensitivity.

  However, in the state immediately before closing when the door part approaches the opening part, the shielding electrode 15 and the sensor electrode 11 are close to each other, and the electric fields from both electrodes 15 and 11 are superimposed. At this time, if the potential of the shield electrode 15 is the same as or close to that of the sensor electrode 11, even if an obstacle is present in the opening space 10 between the electrodes 15, 11, the obstacle is present in the sensor electrode 11. Almost no change in capacity due to. The opening space 10 sandwiched between the electrodes 15 and 11 having the same potential is equalized, and even if an obstacle is interposed there, charging / discharging does not occur. Therefore, the change of the capacitance Ca measured by the charge / discharge does not occur. That is, the effect of the active shielding extends to an obstacle near the shielding electrode 15 and the detection sensitivity is lowered.

  Originally, an obstacle interposed in the opening space 10 with a narrow interval should cause a very large capacitance change in the sensor electrode 11 when the distance from the sensor electrode 11 becomes close. That is, immediately before the door is closed, even a small object should be detected with high sensitivity at a close distance. However, due to the superimposed electric field from the shielding electrode 15, there is a disadvantage that the detection sensitivity is greatly lowered even though it is a nearby obstacle.

  In order to avoid such an inconvenience, the shielding voltage generation circuit 32 is configured so that the electric field in the vicinity of the sensor electrode 11 detected by the probe electrode 13 and the electric field strength detection circuit 31 is maintained at a predetermined setting level. The applied voltage VS to the electrode 15 is variably controlled. As a result, as shown in FIG. 2B, when the shield electrode 15 and the sensor electrode 11 are close to each other, a constant electric field strength gradient is formed in the opening space 10 sandwiched between the electrodes 15 and 11. The detection sensitivity of the obstacle present in the opening space 10 can be ensured. In this case, the shielding electrode 15 appears to be effectively large from the sensor electrode 11, but the change in the capacitance Ca due to the nearby obstacle is observed to be large, thereby reducing the detection sensitivity. There is no.

  As described above, an obstacle detection device for a higher performance automatic door control system that can reliably detect a closing obstacle even when the door part approaches the opening part is realized.

  FIG. 3 shows a main part of another embodiment of the present invention. In the same figure, (a) shows the electrode configuration of the proximity sensor 40 in a perspective view. (B) shows a part of the electrode configuration in a sectional view. (C) is a block diagram showing the sensor circuit 20 and the surrounding electronic circuit portion.

  In the embodiment shown in the figure, reference electrodes 12 that are adjacent and parallel to each other at a predetermined interval are arranged along the sensor electrode 11. The reference electrode 12 is disposed at a position hidden behind the sensor electrode 11 with respect to the opening space 10 to be opened and closed. The two electrodes 11 and 12 are electrostatically shielded by a shielding electrode (sensor-side shielding electrode) 14 in a non-detection direction that does not face the opening space 10 that is opened and closed. The sensor-side shielding electrode 14 has a substantially U-shaped cross section and surrounds the two electrodes 11 and 12 from three directions. The three electrodes 11, 12, and 14 are electrically independent from each other, but are structurally integrated. In this case, a spacer 121 having a low dielectric constant may be used for positioning the electrode as necessary.

  A probe electrode 13 for detecting an electric field is provided in the vicinity of the sensor electrode 11. The probe electrode 13 is also an electrically independent electrode, but is structurally integrated with the electrodes 11, 12, and 14 and attached to the door member.

  The sensor circuit 20 includes two capacitance detection circuits 21 and 22 and one differential amplifier circuit 23, and detects the electrostatic capacitances Ca and Cb formed by the sensor electrode 11 and the reference electrode 12 respectively, thereby generating a voltage. In addition to the conversion, the difference between the two detection outputs Vca and Vcb is output as the proximity detection output Vo. This output Vo reflects the change in capacitance of the sensor electrode 11 due to an obstacle. Therefore, the proximity of the obstacle can be determined from the output Vo.

  As described above, the probe electrode 13 senses an electric field acting in the vicinity of the sensor electrode 11. The electric field strength detection circuit 31 detects the strength of the electric field sensed by the probe electrode 13. The shielding voltage generation circuit 32 applies the voltage VS generated based on the output level of the electric field strength detection circuit 31 to the shielding electrode 15, and applies the above-described application so that the output level of the electric field strength detection circuit 31 is maintained at a set value. The voltage VS is variably controlled.

  FIG. 4 shows a main part of still another embodiment of the present invention. The two electrodes 11 and 12 described above can have both functions of a proximity sensor and a contact sensor, as shown in (a) and (b) of FIG. In the figure, (a) is a non-detection state of the contact sensor, and (b) is a sectional view showing the detection state of the contact sensor.

  In the embodiment shown in the figure, the sensor electrode 11 is configured as a movable electrode, and a cushioning actuator 111 made of rubber or the like is provided on the front surface of the sensor electrode 11. When this actuator 111 abuts against an obstacle such as a finger or the shielding electrode 15 on the opening member side, the sensor electrode 11 is driven to be displaced and brought into electrical contact with the reference electrode 12. Therefore, if the presence or absence of a short circuit between the sensor electrode 11 and the reference electrode 12 is detected, the contact of an obstacle can be detected. The reference electrode 12 in this case <functions as a sensor electrode of the contact sensor.

  (C) shows the structural example of the sensor circuit 20 corresponding to both functions of a proximity sensor and a contact-type sensor. The sensor circuit 20 shown in the figure includes operational amplifiers OP1 to OP4, voltage comparators CP11 and CP12, switching circuits S1 to S3, gain setting resistors R1a, R2a, R1b, and R2b, feedback capacitors Cfa and Cfb, and the like. .

  The switching circuits S1 and S2 are alternately turned on / off in synchronization with a clock having a predetermined period. The switching circuit S3 is controlled so as to be on only for a certain period within the period in which the switching circuit S1 is off. The resistors R1a and R1b, and R2a and R2b are set to the same value (R1, R2) (R1 = R1b = R1, R2a = R2b = R2). The capacitors Cfa and Cfb are also set to the same value (Cf) (Cfa = Cfb = Cf1). Vr1 to Vr4 are reference voltages, respectively.

  The operational amplifier OP1, the switching circuits S1 and S2, and the feedback capacitor Cfa form a switched capacitor type capacitance detection circuit 21 that detects the capacitance Ca appearing in the sensor electrode 11, and the capacitance ratio (impedance ratio) of Ca and Cfa. A voltage corresponding to is periodically output. Similarly, the operational amplifier OP2, the switching circuits S1 and S2, and the feedback capacitor Cfb form a switched capacitor type capacitance detection circuit 22 that detects the capacitance Cb appearing at the reference electrode 12, and the capacitance ratio of Cb and Cfb is set. The corresponding voltage is output periodically.

The operational amplifier OP3 and the gain setting resistors R1a, R2a, R1b, and R2b form a differential amplifier circuit 23 that outputs a difference between capacitance detection voltages output from the two capacitance detection circuits 21 and 22, respectively. This differential output voltage is sampled and held for each switching period by an analog storage circuit 24 including an operational amplifier OP3, a switching circuit S3, a capacitive element C1, and the like. This holding output voltage is input to the post-processing circuit (not shown) as the proximity detection output Vo.
The circuit described above detects a change in the capacitance of the sensor electrode 11 due to an obstacle, converts the voltage, and uses this as the proximity detection output Vo.

Here, in the non-contact detection state in which the sensor electrode 11 and the reference electrode 12 are not short-circuited, the difference Ca−Cb = ΔCi between the capacitances Ca and Cb appearing on the electrodes 11 and 12 is amplified and output. This output Vo (voltage) can be expressed as the following equation (1).
That is, Cfa = Cfb = Cf1, R1 = R1b = R1, R2a = R2b = R2
So if R2 / R1 = n,
Vo = (ΔCi / Cf) × Vr1 × n + Vr2 (1)
It becomes.
In the contact detection state in which the sensor electrode 11 and the reference electrode 12 are short-circuited, the difference Ca−Cb = ΔCi between the capacitances Ca and Cb becomes zero. Therefore, the output voltage Vo expressed by the equation (1) is expressed by )become that way.
Vo = Vr2 (2)

  Therefore, it can be determined that the output voltage Vo is in the non-contact detection state when it is in the state represented by Expression (1), and that it is in the contact detection state when it is in the state represented by Expression (2). This determination can be easily performed by discriminating the level of the output voltage Vo if a slight difference (Ca ≠ Cb) is provided between Ca and Cb. In order to perform this level discrimination, the circuit shown in the figure uses a window comparator 25 using two voltage comparators CP11 and CP12 and two comparison reference voltages Vr3 and Vr4. Thus, by adding some circuits to the circuit for performing proximity detection, both proximity detection and contact detection can be performed.

FIG. 5 shows a specific configuration example of an electronic circuit portion suitable for use in the present invention.
In the figure, first, as described above, the capacitances Ca and Cb appearing on the sensor electrode 11 and the reference electrode 12 are individually detected by the first and second capacitance detection circuits 21 and 22 and converted into voltage. Is done. The difference between the two detection outputs is output via the differential amplifier 23 and the analog storage circuit 24. Then, this output Vo is delivered as detection information to the digital control unit 50 which is a post-processing circuit (post circuit).

  Although not shown, the digital control unit 50 has both analog and digital interfaces in addition to a microcontroller that performs digital processing, and determines the proximity or contact of an obstacle based on the detection output Vo. On the basis of this determination, for example, a detection process of a finger of the automatic opening / closing door is performed, and a control process such as controlling the closing operation of the door based on this detection is executed.

  In the sensor circuit 20, when the capacitance Ca appearing in the sensor electrode 11 is increased, the proximity detection output Vo becomes excessive. Therefore, in the illustrated embodiment, there is provided a charge assist circuit 27 that supplements the charging current to the capacitor Ca and suppresses the proximity detection output Vo to a certain level or less when the proximity detection output Vo becomes a set value or more. . The auxiliary charging circuit 27 includes a voltage comparator CP1 that detects whether or not the proximity detection output Vo has become a specified value or more, a register (SAR) 271 that digitally sets the magnitude of the charging supplementary current, and a set value of the register 271 It comprises a D / A converter DA1 for analog conversion, an inverting circuit IV1 for converting the analog conversion output into two phases (phase division), output variable drivers BA1 and BA2 for outputting a charge replenishment current via a capacitive element Cc, and the like. Yes. This suppresses the proximity detection output Vo from becoming excessive when the capacitance Ca increases.

  The electric field strength detection circuit 31 and the shield voltage generation circuit 32 include a switching circuit S1, operational amplifiers OP5 to OP8, a voltage comparator CP2, D / A converters DA1 and DA2, an up / down counter 321 and an output variable driver BA3. Has been. The operational amplifier OP5 and the switching circuit S1 detect the electric field strength acting on the probe electrode 13. The electric field detection output is inverted and amplified by the operational amplifier OP6 and then held in the analog storage circuit 311.

  The analog storage circuit 311 is configured using an operational amplifier OP7, a switching circuit S3, and the like, and periodically samples and holds the electric field detection output (voltage). The electric field detection output voltage held here is compared with a predetermined comparison reference voltage by the voltage comparator CP2. The comparison reference voltage is generated by analog conversion of the digital set value (SSR) by the D / A converter DA2. The digital set value (SSR) is given from the control unit 50 side.

  The up / down counter 321 is preset with an initial value SSP given from the control unit 50. This preset value is increased or decreased according to the comparison output of the voltage comparator CP2. The count value reduced or increased in this way is converted into an analog signal by the D / A converter DA3. This analog conversion output is given as an output voltage control signal to the output variable driver BA3 via the operational amplifier OP8. The voltage variably output by the output variable driver BA3 is applied to the shielding electrode 15 as the shielding voltage VS. As a result, the voltage VS applied to the shield electrode 15 is feedback controlled so that the electrolytic strength acting on the probe electrode 13 is kept at a constant value. The up / down counter 321 is increased / decreased in the direction in which the feedback control is performed.

  Here, the appropriate value of the shielding voltage in the door open state varies depending on the shape of the electrodes 11, 12, 13, 14 and the mounting conditions thereof. Therefore, in the obstacle detection device of the automatic door control system equipped in a vehicle such as an automobile, it is necessary to set the shielding power in the door open state for each vehicle type. Therefore, in the above circuit, the set value in the shielding voltage generation circuit 32 is determined based on the output level of the electric field strength detection circuit in the door open state.

  In the above circuit, the output level VSSSC of the electric field strength detection circuit 32 in the door open state is taken into the digital control unit 50. The digital processing unit 50 executes processing for determining the set value (appropriate value) based on the output level (VSSC), and in accordance with the processing result, the preset value (SSP) of the up / down counter 321 and the voltage comparison. The digital set value (SSR) of the device VP is set. The setting result is stored in a nonvolatile memory.

  This setting may be performed for each vehicle type in a vehicle such as an automobile, but the setting is automatically processed as described above. Therefore, if necessary, it can be performed for each vehicle. Similarly, the setting value of the register (SAR) 271 for digitally setting the magnitude of the charge replenishment current can be automatically set individually by the digital processing unit 50.

  The digital control unit 50 is expressed as a different configuration in the illustrated example. However, the control unit 50 includes other electronic devices including the sensor circuit 20, the electric field strength detection circuit 31, the shield voltage generation circuit 32, and the like. Along with the circuit portion, it can be integrated on the same semiconductor chip (so-called LSI).

  As described above, the present invention has been described based on the representative embodiments, but the present invention can have various modes other than those described above. For example, the proximity sensor 40 may be attached to the opening member side, and the shielding electrode 15 may be attached to the door member side. Capacitance detection circuits 21 and 22 may be of a system other than a switched capacitor, such as one that detects a change in capacitance by a change in oscillation frequency.

It is a block diagram which shows the outline | summary of the obstruction detection apparatus of the automatic door control system by one Embodiment of this invention. It is a conceptual diagram which shows the electric field state of the opening space where the detection by the sensor electrode by this invention is performed. It is the perspective view, sectional drawing, and block diagram which show the principal part of another embodiment of this invention. It is sectional drawing and the circuit diagram which show the principal part of another embodiment of this invention. It is a circuit diagram which shows the specific structural example of the electronic circuit part of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Opening space opened and closed 11 Sensor electrode 12 Reference electrode 111 Cushioning actuator 121 Low dielectric constant spacer 13 Probe electrode 14, 15 Shielding electrode 16 Opening member side part 21, 22 Capacitance detection circuit 23 Differential amplification circuit 24 Analog memory circuit 25 Window Comparator 27 Charging Auxiliary Circuit 271 Register 31 Field Strength Detection Circuit 32 Shielding Voltage Generation Circuit 40 Capacitive Proximity Sensor 50 Digital Control Unit (Microcontroller)
Ca Capacitance of the sensor electrode 11 Cb Capacitance of the reference electrode 12

Claims (6)

An obstacle detection device for an automatic door control system specified by the following items (1) to (7).
(1) Obstacle detection of an automatic door control system that includes a capacitive proximity sensor, a shielding electrode, an electric field strength detection circuit, and a shielding voltage generation circuit, and detects the presence of an obstacle in the space where the door is closed. Being a device,
(2) The capacitance type proximity sensor is attached to one member of the door member and the opening member that forms an opening space that expands and contracts as the door is opened and closed with the discrimination threshold facing the opening space, Including a sensor circuit and a probe electrode;
(3) The sensor circuit detects whether there is an obstacle in the vicinity of the discrimination threshold based on the grounding capacitance formed by the sensor electrode,
(4) The probe electrode is disposed in the vicinity of the sensor electrode,
(5) The electric field strength detection circuit detects the electric field strength sensed by the probe electrode,
(6) The shielding electrode is attached to the other member of the door member and the opening member, and covers the portion close to the capacitive proximity sensor when the door is closed from the capacitive proximity sensor side,
(7) The shielding voltage generation circuit applies a voltage generated based on the output level of the electric field strength detection circuit to the shielding electrode, and variably controls the applied voltage so that the output level of the electric field strength detection circuit is maintained at a set value. To do, The obstacle detection device for an automatic door control system according to claim 1, wherein the set value in the shielding voltage generation circuit is set based on an output level of the electric field strength detection circuit in the door open state. The capacitive proximity sensor includes a reference electrode,
The reference electrode is arranged so as to be hidden behind the sensor electrode when viewed from the opening space,
The obstacle detection device for an automatic door control system according to claim 1 or 2, wherein the sensor circuit outputs a detection signal based on a difference between a capacitance formed by the sensor electrode and a capacitance formed by the reference electrode. The sensor electrode is configured as a movable electrode that is driven to move by contact pressing from the opening space side and contacts the reference electrode.
The obstacle detection device for an automatic door control system according to claim 3, wherein the sensor circuit includes a circuit for detecting contact between the sensor electrode and the reference electrode. The sensor electrode is configured as a movable electrode that is driven to displace by the contact pressure from the opening space side and approaches the reference electrode,
The obstacle detection device for an automatic door control system according to claim 3, wherein the sensor circuit includes a circuit that detects approach of both electrodes based on a capacitance formed by the sensor electrode and a capacitance formed by the reference electrode. The obstacle detection device for an automatic door control system according to claim 4, wherein the capacitive proximity sensor includes a cushioning actuator disposed on a front side of the sensor electrode.

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