JP2005201661A - Inclination detecting apparatus for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive inclination detecting apparatus for automobiles, having high inclination detection accuracy. <P>SOLUTION: Magnetic distance sensors are mounted to two points in a coil spring 12 of each suspension S at four locations or two locations of a four-wheel vehicle body 11, to periodically measure the distances LF and LR of the coil springs 12 at regular time intervals. On the basis of the lengths LF and LR of the coil springs 12 of a front wheel and of a rear wheel, the angle θ of inclination in the longitudinal direction of the vehicle body 11 is detected. The distance sensors are constituted of a magnet mounted to a part of the coil spring 12, and a Hall device arranged adjacent to the magnet according to the extension and contraction of the coil spring 12. There is no need for an expensive ultrasonic distance sensor for detecting the inclination of a vehicle, as before. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automotive tilt detection apparatus and related technology.

  For the purpose of adjusting the optical axis of a headlamp and the like, conventionally, an automobile inclination detection device for detecting the inclination of a vehicle has been used. In particular, the inclination angle of the vehicle relative to the road surface changes depending on the number of passengers, the seating position (front and rear seats), the luggage loading situation of the trunk, and the slope of the road surface such as a slope. It is useful to adjust the optical axis of the lamp.

  For example, Japanese Patent Application Laid-Open No. 2004-151867 discloses this automobile inclination detection device. As shown in FIG. 8, this patent document 1 reflects the ultrasonic wave on the ground G at two locations in the vehicle width direction below the driver's seat of the vehicle body 1 and the distance from the ultrasonic wave reflection time to the ground G, In other words, ultrasonic distance sensors 2 and 3 for measuring the vehicle height and detecting the inclination angle Δα of the vehicle body 1 are provided. Specifically, each of the distance sensors 2 and 3 includes an ultrasonic oscillator 2a and 3a and an ultrasonic receiver 2b and 3b. The first vehicle height L1 measured by one distance sensor 2 and the other A difference ΔS from the second vehicle height L2 measured by the distance sensor 3 is calculated, and the inclination angle Δα of the vehicle body 1 is detected based on this ΔS.

JP 2003-118476 A

  In Patent Document 1 described above, since the expensive ultrasonic distance sensors 2 and 3 are used to detect the inclination of the vehicle, the cost is increased.

  Further, since the ultrasonic wave is reflected on the ground and the inclination angle is detected from the reflection time, an influence such as irregular reflection appears depending on the road surface condition, and the inclination detection accuracy may be lowered.

  Furthermore, although distance sensors 2 and 3 were arranged at two places below the driver's seat and the respective vehicle heights were measured, since the two places where the distance sensors 2 and 3 are arranged are close to each other, It was difficult to increase the inclination detection accuracy.

  Therefore, an object of the present invention is to provide an automobile inclination detection device that is inexpensive and has high inclination detection accuracy.

  In order to solve the above-mentioned problem, the invention according to claim 1 is an automobile inclination detection device for detecting an inclination angle of a vehicle body with respect to a road surface, wherein the vehicle bodies differ so as to expand and contract with a change in vehicle height with respect to the road surface. A plurality of distance sensors that respectively detect the degree of expansion / contraction of the plurality of expansion / contraction members disposed at positions, and a calculation unit that calculates the inclination angle of the vehicle body based on the expansion / contraction degree of each expansion / contraction member detected by each distance sensor Are provided.

  Invention of Claim 2 is the inclination detection apparatus for motor vehicles of Claim 1, Comprising: The said distance sensor is a magnet installed in the predetermined position of the said expansion-contraction member, and said expansion-contraction of the said expansion-contraction member WHEREIN: And a Hall element that can be separated from and connected to the magnet.

  A third aspect of the present invention is the automotive tilt detection apparatus according to the first or second aspect, wherein the telescopic member is a suspension that buffers the road surface of the vehicle body.

  Invention of Claim 4 is the inclination detection apparatus for motor vehicles in any one of Claim 1 to 3, Comprising: The said distance sensor is installed in all the positions of the four-wheels of a motor vehicle. is there.

  According to a fifth aspect of the present invention, there is provided the automotive tilt detection apparatus according to the fourth aspect, wherein the calculation means detects a tilt angle of the vehicle body in the front-rear direction, and the vehicle body front side The average value of the two vehicle height values calculated based on the detection results of the left and right distance sensors is calculated, and the two calculated values are calculated based on the detection results of the left and right distance sensors on the rear side of the vehicle body. An average value of vehicle height values is obtained, and an inclination angle of the vehicle body in the front-rear direction is calculated based on the difference between the two average values.

  A sixth aspect of the present invention is the vehicle tilt detection apparatus according to any one of the first to third aspects, wherein the distance sensor is provided in a pair, and the both distance sensors are arranged on a four-wheeled vehicle. Among them, they are installed at two points on a straight line that crosses the vicinity of the center point in plan view of the vehicle body.

  The invention according to claim 7 is the automotive tilt detection apparatus according to claim 5 or 6, wherein the calculation means has a function of adjusting the optical axis of the headlamp based on the tilt angle. It has been stuffed.

  The invention according to claim 8 is the automotive tilt detection apparatus according to any one of claims 1 to 7, wherein the calculation means includes a time measuring means, and is constant based on the time measured by the time measuring means. The tilt angle of the vehicle body is calculated based on the expansion / contraction degree of each expansion / contraction member from the distance sensor at time intervals.

  According to a first aspect of the present invention, there is provided a tilt detection apparatus for an automobile, in which distance sensors are respectively installed on a plurality of telescopic members disposed at different positions of a vehicle body so as to expand and contract with a change in vehicle height with respect to a road surface. Since the degree of expansion / contraction of the expansion / contraction member is detected based on the distance between the two points of the member, and the vehicle body inclination angle is calculated based on the expansion / contraction degree of each expansion / contraction member, the vehicle height is detected by road surface reflection as in the past. The vehicle height detection accuracy is improved.

  In particular, as described in claim 2, by applying a Hall element as the distance sensor, it is not necessary to use an expensive ultrasonic distance sensor in order to detect the inclination of the vehicle. Therefore, the cost can be reduced, and an inexpensive automotive inclination detection device can be realized.

  In the vehicle inclination detecting device according to the third aspect of the invention, since the expansion / contraction member is a suspension that cushions the road surface of the vehicle body, the vehicle height change with respect to the road surface can be reliably captured, and the distance sensor can provide high accuracy. A change in vehicle height can be detected.

  Since the distance sensor is installed at all positions of the four wheels of the automobile, the vehicle inclination detection device according to the invention of claim 4 can reliably detect the front, rear, left and right inclination angles of the vehicle body.

  According to a fifth aspect of the present invention, there is provided a vehicle tilt detection apparatus for detecting a tilt angle in the front-rear direction of a vehicle body, for example, when adjusting the optical axis of a headlamp as in the seventh embodiment. From the average value of the front vehicle height and the average value of the rear vehicle height, the inclination angle of the vehicle body in the front-rear direction can be easily calculated.

  In the tilt detection apparatus for an automobile according to the sixth aspect of the invention, the pair of distance sensors are installed at two points on a straight line that crosses the vicinity of the center point in plan view of the vehicle body among the four wheels of the automobile. Only a pair of distance sensors can detect the vehicle height in the longitudinal direction and the lateral direction of the vehicle body. Therefore, when detecting the tilt angle in the front-rear direction of the vehicle body, for example, when adjusting the optical axis of the headlamp as in claim 7, the vehicle height at the front of the vehicle body and the vehicle height at the rear of the vehicle body are used. The inclination angle of the vehicle body in the front-rear direction can be easily calculated.

  According to an eighth aspect of the present invention, there is provided a vehicle inclination detecting device that determines the inclination angle of a vehicle body based on the degree of expansion / contraction of each expansion / contraction member from a distance sensor at regular time intervals based on the time measured by the time counting means of the calculation means. Since the calculation is performed, it is possible to accurately detect the inclination angle that changes over time. In particular, because the inclination angle of the vehicle body with respect to the road surface changes depending on various situations such as changes in the number of passengers, changes in the seating position, trunk loading conditions, and slopes of road surfaces such as hills, The change in the tilt angle can be detected with high accuracy.

<Configuration>
FIG. 1 is a plan view showing the mounting position of a vehicle tilt detection device according to an embodiment of the present invention in a vehicle, and FIG. 2 is a front view showing the position of a suspension to which a distance sensor of the vehicle tilt detection device is mounted in the vehicle. FIG. 3 is a block diagram showing a tilt detector for an automobile.

  As shown in FIG. 1, FIG. 2 and FIG. 3, the vehicle inclination detection device is provided with a plurality of devices provided to expand and contract in the vertical direction with respect to the rotation shafts of the four wheels for the purpose of buffering the vehicle body 11 of the vehicle. The distance sensors 13a to 13d for detecting the degree of expansion / contraction are respectively disposed on the expansion / contraction members, and the inclination angle of the vehicle body 11 is detected based on the detection results of the distance sensors 13a to 13d.

  Specifically, this automotive inclination detection device is attached to each coil spring (extensible member) 12 of each suspension provided in the automobile, and detects four magnetic distances for detecting the expansion / contraction dimension of each coil spring 12. Sensors 13a to 13d and an electronic control unit (ECU) 14 as a calculation means for calculating the inclination angle of the vehicle based on the detection results of the four distance sensors 13a to 13d are provided.

  In general, as shown in FIG. 4, a suspension S of an automobile is provided with a pair of shafts arranged in such a manner that its axial direction is substantially vertical so as to support the rotation shafts of the four wheels from the side of the vehicle body 11. A coil spring 12 is wound around the rods 21 and 22 around the rods 21 and 22. With this configuration, the suspension S can be ridden by reducing the impact acting on the vehicle body 11 by extending and contracting the rods 21 and 22 and the coil spring 12 while supporting the load of the vehicle body 11 when the vehicle receives an impact from the road surface. In addition to improving the comfort, the wheel is held in an appropriate direction by ensuring the contact of the four wheels when cornering. In this embodiment, it is assumed that the suspension S is provided corresponding to the front and rear tires (four wheels) of the vehicle body 11, respectively. In this case, the suspension S functions as a plurality of elastic members that expand and contract in the vertical direction in order to cushion the road surface of the vehicle body 11.

  The distance sensors 13a to 13d of the vehicle inclination detection device are located at positions separated from the magnet 24 disposed in a part of the coil spring 12 of the suspension S in the expansion and contraction direction of the coil spring 12, as shown in FIG. And a Hall element 25 that is disposed and magnetically detects the distance from the magnet 24.

  The magnet 24 is a general permanent magnet.

  The Hall element 25 is a semiconductor element made of, for example, gallium or arsenic. As shown in FIG. 5, a Hall voltage Vh is generated when a magnetic field is applied to the Hall element 25 in a state where a current I flows. Is used to convert the state of the magnetic field that changes with the change in the separation distance of the Hall element 25 from the magnet 24 into the Hall voltage Vh as an electrical signal and output it to the electronic control unit (ECU) 14. Is. Even if only the direction of the current I is reversed while the intensity of the magnetic field is constant and the magnitude of the current I flowing in the Hall element 25 is left unchanged, the sign of the Hall voltage Vh is only reversed. The absolute value is the same. Therefore, when the electronic control unit (ECU) 14 detects the Hall voltage Vh, it is desirable to detect the absolute value.

  Here, since the Hall element 25 converts the change in the separation distance from the magnet 24 into the Hall voltage Vh, the vertical relationship between the Hall element 25 and the magnet 24 is the upper one. There is no problem. And the attachment position of both 24 and 25 is arrange | positioned in the position which adjoins up and down in the coil spring 12, for example.

  The current I flowing through the Hall element 25 is set to a constant current and is supplied from any current supply device such as an electronic control unit (ECU) 14 or a predetermined constant current circuit (not shown).

  The electronic control unit (ECU) 14 calculates the inclination angle of the vehicle body 11 based on the Hall voltage Vh (absolute value) obtained by the Hall elements 25 of the distance sensors 13a to 13d. 3, for example, the actuator 27 for adjusting the optical axis of the headlamp is driven and controlled.

  Specifically, the electronic control unit (ECU) 14 is a functional element in which various data calculation processing components such as a ROM, a RAM, and a CPU are built in, and a predetermined built-in in the electronic control unit (ECU) 14. It functions based on a software program stored in advance in the nonvolatile storage device. As a function defined by the software program of the electronic control unit (ECU) 14, the vehicle in each suspension S is based on the respective hall voltages Vh given from the hall elements 25 of the four distance sensors 13a to 13d. Based on the vehicle height calculation function for calculating the height, the inclination angle calculation function for calculating the inclination angle of the vehicle body 11 with respect to, for example, the front-rear direction and the left-right direction based on the difference between the calculated vehicle heights, and the calculated inclination angle And a drive control function for controlling the drive of the actuator 27 for adjusting the optical axis of the headlamp.

  In the calculation using the vehicle height calculation function, the electronic control unit (ECU) 14 determines each hall of each distance sensor 13a to 13d based on a predetermined function or a data table stored in advance in a built-in nonvolatile storage device. The hall voltage Vh applied from the element 25 is converted into a vehicle height value in each suspension S. In this case, based on the Hall voltage Vh, after obtaining the separation distance between the magnet 24 and the Hall element 25 arranged at positions adjacent to each other in the coil spring 12 in the vertical direction, the number N of turns of the coil spring 12 is set at this separation distance. Is integrated, the length of the entire length of the coil spring 12, that is, the vehicle height can be easily calculated. In the following description, four vehicle height values calculated based on the respective hall voltages Vh detected at the portions of the coil springs 12 of the four suspensions S on the left and right sides of the vehicle body 11 are represented by variables. It is represented by LF1, variable LF2, variable LR1, and variable LR2. The variable LF1 is the value of the vehicle height in the suspension S arranged on the right front side of the vehicle body 11, the variable LF2 is the value of the vehicle height in the suspension S arranged on the left front side of the vehicle body 11, and the variable LR1 is the right value of the vehicle body 11. The value of the vehicle height in the suspension S disposed on the rear side and the variable LR2 indicate the value of the vehicle height in the suspension S disposed on the left rear side of the vehicle body 11, respectively.

  In the calculation by the tilt angle calculation function, the electronic control unit (ECU) 14 determines the vehicle body 11 based on the front vehicle height LF and the rear vehicle height LR as shown in FIGS. An inclination angle θ in the front-rear direction is calculated. The front vehicle height LF and the rear vehicle height LR of the vehicle body 11 are average values of left and right vehicle height values (LF1 and LF2, LR1 and LR2) according to the following equations (1) and (2), respectively. Desired.

LF = (LF1 + LF2) / 2 (1)
LR = (LR1 + LR2) / 2 (2)

  If the separation distance between the right front distance sensor 13a and the right rear distance sensor 13c and the separation distance between the left front distance sensor 13b and the left rear distance sensor 13d are both variables A, the variable A It is almost equal to the length of the four-wheel wheelbase in the longitudinal direction. Therefore, the longitudinal length A of the wheel base is stored in advance in the electronic control unit (ECU) 14, and the variable A is used to determine the inclination angle θ in the longitudinal direction of the vehicle body 11 as the following (3). Calculated according to the formula.

θ = tan ⁻¹ ((LF−LR) / A) (3)

  Note that the variable A is a value that varies depending on the vehicle case and the vehicle type, and is stored in advance in a built-in nonvolatile storage device.

  In the calculation by the drive control function, the electronic control unit (ECU) 14 determines the light of the left and right headlamps (not shown) based on the inclination angle θ in the longitudinal direction of the vehicle body 11 obtained by the equation (3). The drive control of the actuator 27 is performed so that the axis is corrected by the inclination angle θ.

  The electronic control unit (ECU) 14 receives a signal from the vehicle speed sensor 28, and at a certain time interval (for example, 1) according to the time measured by a predetermined time measuring means (timer: not shown) incorporated therein. Second), the hall voltages Vh from the hall elements 25 of the distance sensors 13a to 13d are received, and the drive control of the actuator 27 is performed based on this.

<Operation>
The operation of the automobile tilt detection apparatus having the above configuration will be described. In FIG. 3, when the automobile starts traveling, the electronic control unit (ECU) 14 operates when a signal from the vehicle speed sensor 28 is given.

  At this time, as shown in FIG. 4, a current I that is a constant current flows through each Hall element 25 of the distance sensors 13 a to 13 d installed in each suspension S, and a magnet disposed in the coil spring 12. A distance from 24 is magnetically detected, and a hall voltage Vh corresponding to the distance is output to an electronic control unit (ECU) 14.

  At this time, the electronic control unit (ECU) 14 moves the halls of the distance sensors 13a to 13d at a constant time interval (for example, 1 second) according to the time measured by a built-in time measuring means (timer: not shown). Each Hall voltage Vh from the element 25 is received.

  And the hall voltage Vh given from each hall element 25 of each distance sensor 13a-13d is converted into the value of the car height in each suspension S by the vehicle height calculation function of the electronic control unit (ECU) 14.

  Subsequently, the tilt angle θ in the front-rear direction of the vehicle body 11 is calculated by the tilt angle calculation function of the electronic control unit (ECU) 14 according to the above-described formulas (1), (2), and (3).

  Then, by the drive control function of the electronic control unit (ECU) 14, the optical axes of the left and right headlamps (not shown) are adjusted based on the tilt angle θ in the longitudinal direction of the vehicle body 11 obtained by the tilt angle calculation function. The drive control of the actuator 27 is performed so that only the inclination angle θ is corrected.

  As described above, an ultrasonic Hall sensor 25 is used by detecting the inclination angle θ of the vehicle body 11 by installing the inexpensive Hall element 25 on the coil spring 12 of the suspension S of each of the four wheels of the vehicle body 11. Compared with the prior art, an inexpensive tilt detector for automobiles can be realized.

  Further, since the inclination angle θ of the vehicle body 11 can be detected without performing road surface reflection as in the prior art, the influence of road surface conditions such as irregular reflection can be avoided, and the inclination angle θ can be detected with high accuracy.

  Further, since the expansion and contraction of the coil spring 12 of each suspension S is detected by the distance sensors 13a to 13d, the installation positions of the distance sensors 13a to 13d detect the inclination angle θ using the distance between the front and rear axles (wheel base). The distance range in the front-rear direction between the distance sensors 13a to 13d can be made longer than in the prior art in which the inclination angle θ is detected only by the distance sensors provided on the left and right sides of the vehicle body as in the past. Therefore, the detection accuracy of the inclination angle θ can be improved.

  Furthermore, since the degree of expansion and contraction of the coil spring 12 is periodically measured at regular time intervals, the inclination angle θ that changes with time can be detected with high accuracy. In particular, the angle of inclination of the vehicle body 11 with respect to the road surface changes depending on various situations such as changes in the number of passengers, changes in seating positions, trunk loading conditions, and slopes of road surfaces such as slopes. It is significant to adjust the optical axis of the headlamp by detecting the inclination angle θ of the vehicle body 11.

  In the above embodiment, the distance sensors 13a to 13d are set for all the suspensions S of the four wheels. However, if the purpose is to set the inclination angle θ in the front-rear direction of the vehicle body 11, the front side of the vehicle body 11 is limited. One distance sensor is installed only on the coil spring 12 of the left or right suspension S, and the other distance sensor is installed only on the coil spring 12 of the left or right suspension S on the rear side of the vehicle body 11. Thus, it is possible to calculate the inclination angle θ in the longitudinal direction of the vehicle body 11 using only these two distance sensors.

  In this case, it is desirable to arrange the pair of distance sensors so that a straight line connecting the pair of distance sensors crosses the vicinity of the center point in plan view of the vehicle body 11. For example, when one distance sensor is installed on the coil spring 12 of the right front suspension S (distance sensor 13a in FIG. 1), the other distance sensor for the distance sensor 13a is replaced with the coil spring of the left rear suspension S. 12 (distance sensor 13d), and the inclination angle θ of the vehicle body 11 is calculated by a pair of both distance sensors 13a and 13d. Alternatively, when one distance sensor is installed on the coil spring 12 of the left front suspension S (distance sensor 13b in FIG. 1), the other distance sensor for this distance sensor 13b is replaced with the coil spring of the right rear suspension S. 12 (distance sensor 13c), the inclination angle θ of the vehicle body 11 is calculated by the pair of both distance sensors 13b and 13c. In this way, if the pair of distance sensors is arranged so that the straight line connecting the pair of distance sensors crosses the vicinity of the center point of the vehicle body 11 in plan view, the pair of distance sensors may be arranged on the left and right sides, Compared with the case where a pair of distance sensors are arranged on the front and rear of the right side, the inclination angle θ with reference to the vicinity of the center of gravity of the vehicle body 11 can be detected with high accuracy.

  In the above embodiment, the magnets 24 and the hall elements 25 of the distance sensors 13a to 13d are attached to the coil springs 12 of the suspensions S. However, different positions of the vehicle body so as to expand and contract as the vehicle height changes with respect to the road surface. If the degree of expansion / contraction of the expansion / contraction member is detected by the separation distance between two points of the expansion / contraction member, the expansion / contraction member is not necessarily attached to the coil spring 12, for example, One or both may be attached to the rods 21 and 22. In addition, the suspension as the elastic member is not limited to the one using the coil spring 12, but a suspension using a torsion bar, a suspension using a leaf spring (plate spring), or the like may be used. Even in these suspensions, the position where the separation distance between the two points changes depending on the degree of expansion and contraction of the suspension and the Hall element 25 can detect the change of the magnetic field is arranged at any position. It doesn't matter.

It is a top view which shows the installation position in the motor vehicle of the inclination detection apparatus for motor vehicles which concerns on one Embodiment of this invention. It is a front view which shows the position of the suspension of the inclination detection apparatus for motor vehicles which concerns on one Embodiment of this invention. 1 is a block diagram illustrating an automotive tilt detection apparatus according to an embodiment of the present invention. 1 is a side view showing an example in which a distance sensor of an automotive tilt detection device according to an embodiment of the present invention is attached to a suspension. It is a schematic diagram which shows the Hall element of the distance sensor of the inclination detection apparatus for motor vehicles which concerns on one Embodiment of this invention. It is a schematic diagram which shows the vehicle height in each suspension of a vehicle body. It is a schematic diagram which shows the vehicle height in each suspension when the vehicle body is inclined. It is a schematic diagram which shows the distance sensor of the conventional inclination detection apparatus for motor vehicles.

Explanation of symbols

11 Body S Suspension (expandable member)
12 Coil springs 13a to 13d Distance sensor 14 Electronic control unit (calculation means)
21, 22 Rod 24 Magnet 25 Hall element

Claims (8)

An automobile inclination detection device for detecting an inclination angle of a vehicle body with respect to a road surface,
A plurality of distance sensors that respectively detect the degree of expansion / contraction of a plurality of expansion / contraction members disposed at different positions of the vehicle body so as to expand / contract in accordance with a change in vehicle height relative to a road surface;
An automotive tilt detection apparatus comprising: a calculation means for calculating an inclination angle of the vehicle body based on a degree of expansion / contraction of each expansion / contraction member detected by each distance sensor. The vehicle tilt detection device according to claim 1,
The distance sensor is
A magnet installed at a predetermined position of the elastic member;
A tilt detector for an automobile comprising: a hall element that can be separated from and connected to the magnet by expansion and contraction of the expansion and contraction member. An automotive tilt detection device according to claim 1 or claim 2,
A tilt detector for an automobile, wherein the telescopic member is a suspension that cushions a road surface of a vehicle body. An automotive tilt detection device according to any one of claims 1 to 3,
A tilt detection apparatus for automobiles, wherein the distance sensor is installed at all positions of the automobile four wheels. The vehicle tilt detection device according to claim 4,
The calculation means detects an inclination angle of the vehicle body in the front-rear direction, and an average of two vehicle height values calculated based on the detection results of the left and right distance sensors on the front side of the vehicle body A value is obtained, and an average value of two vehicle height values calculated based on detection results of the left and right distance sensors on the rear side of the vehicle body is obtained, and the longitudinal direction of the vehicle body is determined based on the difference between the two average values. A tilt detector for an automobile that calculates the tilt angle of the vehicle. An automotive tilt detection device according to any one of claims 1 to 3,
A vehicle tilt detection apparatus, wherein the distance sensors are provided in a pair, and the distance sensors are installed at two points on a straight line that crosses the vicinity of the center point in plan view of the vehicle body among the four wheels of the vehicle. An automobile tilt detection device according to claim 5 or 6,
A tilt detector for an automobile, wherein the calculation means has a function of adjusting the optical axis of the headlamp based on the tilt angle. An automotive tilt detection apparatus according to any one of claims 1 to 7,
Inclination detection for automobiles, wherein the computing means includes timekeeping means and computes the inclination angle of the vehicle body based on the degree of expansion / contraction of each expansion / contraction member from the distance sensor at regular time intervals based on the timekeeping by the timekeeping means. apparatus.

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