Calibration device for minimum turning radius measuring equipment

Abstract

To provide a calibration device for minimum turning radius measuring instruments that measure the minimum turning radius of a moving object using GPSs and sensors.SOLUTION: A calibration device 10 for minimum turning radius measuring instruments that acquire the movement amount of a moving object using a satellite positioning system and a sensor and measure the minimum turning radius of the moving object, comprises: an arm 32; a detection unit fixing table 34 that is secured to one end of the arm 32 and that fixes in place the movement amount detection unit 12 of a minimum turning radius measuring instrument; and a rotation shaft 22 that pivotally supports the arm 32 so as to be horizontally rotatable. The movement amount detection unit 12 is disposed at a prescribed detection unit fixing position of the detection unit fixing table 34, the arm 32 is pivotally supported to the rotation shaft 22, with the distance between the detection unit fixing position and the rotation shaft 22 set to a preset length, in which the rotation shaft 22 is rotated at a prescribed speed, and the radius of circular trajectory calculated on the basis of the movement amount acquired from the movement amount detection unit 12 is compared with the preset length, so as to calculate an error.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for a device that calibrates equipment that uses GPS and sensors to measure the minimum turning radius of a moving object. A moving object includes mechanically moving objects on land, water, or in the air. This specification describes an example of a car, which is required by law to measure its minimum turning radius. [Background technology]

[0002] With regard to the operation of automobiles, from the viewpoint of ensuring safety and protecting the environment, technical standards are established by law for the structure and equipment of automobiles, and vehicles that do not comply with these standards are prohibited from operation. In Japan, these standards are the "Safety Standards for Road Transport Vehicles" in the Road Transport Vehicle Act.

[0003] Safety standards for ensuring safety stipulate preventive safety measures to prevent accidents from occurring, and damage mitigation measures to minimize damage in the event of an accident.

[0004] The minimum turning radius of a vehicle is one of the requirements that must be met by technical standards in terms of the vehicle's structure.

[0005] The "Safety Standards for Road Transport Vehicles" stipulate that "the minimum turning radius of a motor vehicle must be 12 meters or less for the outermost track." Furthermore, the inspection procedures of the National Agency for Automotive and Land Transport Technology (NALTT) state that the minimum turning radius can be obtained by measurement or calculation, and that the measurement method is to measure the maximum radius of the path traced by the center of the contact patch of the outside tire when turning at low speed with the steering device turned to the maximum right or left.

[0006] Representative methods for obtaining the locus of a circle and measuring the radius of the circle include the following prior art.

[0007] The first method conforms to JIS D 1025-1985, and involves using a tracer, for example, a device with chokes attached in front and behind the center of the tire width of the vehicle, to drive the vehicle at a very slow speed with the steering wheel turned to the maximum, making at least two left and two right turns, and drawing a trail on the ground to measure the radius of the circle.

[0008] The second method is to measure the minimum turning radius by attaching a geomagnetic sensor and an angular velocity sensor to the vehicle. This method does not trace a trajectory on the ground, but the vehicle is driven in the same manner as the first method to acquire data. Patent Document 1 discloses a method for calculating the radius of curvature of a vehicle based on the vehicle speed, the direction of travel of the vehicle, the strength of the magnetic field detected by an on-board geomagnetic sensor, the angle of the direction of the detected magnetic field relative to the direction of travel of the vehicle, and the time rate of change calculated from the actual geomagnetic field strength, instead of using an angular velocity sensor, which is easily affected by external factors, as a direction sensor.

[0009] The third method is to measure the minimum turning radius by attaching a GPS antenna to a vehicle and acquiring position information while the vehicle is traveling with the steering wheel turned to the maximum. Like the second method, this method does not involve drawing a track on the ground, but the vehicle is driven in the same manner as the first method to acquire data. Patent Document 2 discloses a method for measuring the turning radius of a moving object with high accuracy and without requiring much effort or time. The method calculates the speed by processing a GPS carrier wave received by a GPS receiver and data output by an inertial measurement unit that can acquire various physical information using a Kalman filter, and then calculates the turning radius from a movement track calculated based on the travel distance obtained by integrating the calculated speed. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 2693174 [Patent Document 2] Patent No. 5686703 Summary of the Invention [Problem to be solved by the invention]

[0011] Regardless of the measurement method described above, errors occur in the minimum turning radius measurement device due to individual differences in components, the accuracy of the sensors used, the accuracy of the global positioning system (GPS), and the like.

[0012] The first method involves measuring the radius of the traced circle using a tape measure or surveying equipment. Because steel tape measures are used, individual differences can affect the measurement error. Furthermore, in recent years, total stations, which combine an optical distance meter and a zeodride, have become common surveying equipment, and individual differences in the components can be a source of error.

[0013] The second method has the problem that individual differences in sensors affect measurement accuracy.

[0014] The third method involves GPS, but the accuracy of measurements is affected by the number of satellites that can be detected and the influence of external factors surrounding the Earth. In recent years, the accuracy of measurements has improved by correcting the acquired position information using quasi-zenith satellites, but errors still remain.

[0015] Therefore, calibration is required to correct the error, and a reference instrument is required to perform the calibration.

[0016] The surveying equipment and tape measures used in the first method of actually drawing the trajectory of a circle are those that are periodically calibrated using a designated standard instrument and have a calibration certificate issued.

[0017] However, there is currently no specific calibration method for calibrating minimum turning radius measurement devices that do not actually draw a circular trajectory using GPS or sensors, as in the second or third method.

[0018] The present invention has been made in view of the above-mentioned problems, and has an object to provide a calibration device for a minimum turning radius measuring instrument that measures the minimum turning radius of a moving object using a GPS or a sensor. [Means for solving the problem]

[0019] In order to solve the above-mentioned problems, the calibration device for a minimum turning radius measuring device of the present invention is a calibration device for a minimum turning radius measuring device that measures the minimum turning radius of a moving body by obtaining the amount of movement of the moving body using a satellite positioning system or a sensor, and is characterized in that it comprises an arm, a detector unit fixing base for fixing a detector unit of the minimum turning radius measuring device fixed to one end of the arm, and a rotation shaft that supports the arm so that it can rotate horizontally, the detector unit is disposed at a predetermined detector unit fixing position on the detector unit fixing base, the arm is supported on the rotation shaft at a distance between the detector unit fixing position and the rotation shaft that is a preset length, the rotation shaft is rotated at a predetermined speed, and the radius of a circle locus calculated based on the amount of movement obtained from the detector unit is compared with the preset length to calculate an error.

[0020] Furthermore, the calibration device for a minimum turning radius measuring instrument of the present invention is characterized in that the predetermined length is measured by a calibrated surveying instrument and determined by supporting the arm and the rotation axis. [Effects of the Invention]

[0021] Conventionally, there has been no method for measuring the minimum turning radius from data on the amount of movement of a vehicle obtained using an acceleration sensor, a geomagnetic sensor, a GPS, etc., and for calibrating a minimum turning radius measurement device that does not actually trace a circular trajectory. However, the calibration device for a minimum turning radius measuring device of the present invention makes it possible to calibrate the minimum turning radius measurement device.

[0022] According to the calibration device for a minimum turning radius measuring instrument of the present invention, a calibrated surveying instrument is used to determine the length from the rotation axis of the calibration device for a minimum turning radius measuring instrument to the detection unit of the minimum turning radius measuring instrument placed at a predetermined detection unit fixed position, thereby achieving the effect of providing the accuracy required for a calibration device. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a front view of a calibration device 10 for a minimum turning radius measuring device according to the present invention. [Figure 2] 1 is a plan view of a calibration device 10 for a minimum turning radius measurement device according to the present invention. [Figure 3] 1 is a flowchart showing a calibration procedure of the calibration device 10 for a minimum turning radius measurement device according to the present invention. [Figure 4] 1 is an example of an inspection report showing the results of calibration performed by the calibration device 10 for a minimum turning radius measuring instrument according to the present invention. [Figure 5] 1 is a configuration diagram of the calibration device 10 for a minimum turning radius measuring device according to the present invention when adjusting a reference distance. [Figure 6] FIG. 10 is a diagram showing a method for determining a fixed position 524 of the surveying instrument main body for measuring a reference distance. [Figure 7] FIG. 10 is a diagram illustrating a method for determining a reference distance. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment of a calibration device 10 for a minimum turning radius measuring device (hereinafter referred to as the calibration device 10) according to the present invention will be described with reference to the drawings. Fig. 1 is a front view of the calibration device 10 according to the present invention. The calibration device 10 is used when calibrating a device that measures the minimum turning radius from movement amount data acquired from a GPS or sensor, without actually drawing a circular trajectory.

[0025] The calibration device 10 is composed of at least a rotation center portion 20, a rotation arm portion 30, a rail portion 40, and an operation portion 60.

[0026] The rotation center 20 is composed of at least the turntable 24, the motor 26, the motor base 262, the rotating shaft 22, the surveying instrument main body base 52, and the surveying instrument main body base support 522. The rotation center 20 is equipped with a mechanism that changes the rotation speed and rotates the rotating arm 30 in response to commands from the control unit. In addition, the motor base 262 is equipped with a movement amount data acquisition unit 14 that acquires movement amount data from the movement amount detection unit 12, and a rotation radius measurement computer 142 (hereinafter referred to as the rotation radius measurement PC 142) that has the function of measuring the rotation radius. The movement amount data acquisition unit 14, the rotation radius measurement PC 142, and the movement amount data detection unit, which will be described later, correspond to the minimum rotation radius measurement device.

[0027] The turntable 24 has its center portion rotatably supported by the rotary shaft 22. One end of an arm 32 of a rotary arm unit 30 is connected to the turntable 24.

[0028] The motor 26 is mounted on the motor base 262, and the motor shaft is connected to the rotary shaft 22. Therefore, the rotary arm unit 30 rotates in a circular trajectory in synchronization with the rotation of the motor 26. The motor base 262 also includes a motor base height adjuster 264 for adjusting the level of the entire calibration device 10.

[0029] The rotating arm unit 30 is composed of at least an arm 32, a detector fixing base 34, a detector fixing base support 36, and a rotating arm caster 38. The detector fixing base 34 is connected to and fixed at the end of the arm 32 opposite the rotation center 20 via the detector fixing base support 36. The rotating arm caster 38 is attached to the bottom of the detector fixing base support 36 and runs on rails 42. The movement amount detection unit 12 is disposed on the detector fixing base 34 at a predetermined detector fixing position 342, which will be described in detail later. The movement amount detection unit 12 may be a GPS antenna, a geomagnetic sensor, or an angular velocity sensor, but is not limited to these, and may be any device that can electrically detect the amount of movement. The following describes a case where a GPS antenna is used as the movement amount detection unit 12.

[0030] The rail section 40 is composed of at least a rail 42, a rail base 44, and a rail height adjuster 442. The rail 42 is circular, as shown in Fig. 2, which is a plan view of the calibration device 10 according to the present invention. The rail base 44 supports the circumference of the rail 42 from below at predetermined intervals. The underside of the rail 42 is provided with a rail height adjuster 442 that enables the upper surface of the circular rail 42 to be kept horizontal.

[0031] The operation unit 60 remotely controls the rotation of the turntable 24, acquires movement amount data obtained from the GPS antenna via an acquisition unit, acquires the results of measuring the rotation radius by the rotation radius measurement PC 142, calculates errors, and displays calibration results. The operation unit 60 is composed of at least a remote computer 62 (hereinafter referred to as remote PC 62), a wireless unit 64, and a turntable control unit 66, and is placed on an operation unit base 68. The turntable control unit 66 controls the motor 26 that controls the rotation of the turntable 24 based on commands from the remote PC 62. The wireless unit 64 communicates between the remote PC 62 and the rotation radius measurement PC 142. The remote PC 62 sets the rotation conditions of the motor 26 and processes data acquired from the rotation radius measurement PC 142. The remote PC 62 may be a general-purpose computer.

[0032] The calibration procedure using the calibration device 10 of the present invention will be described below. Fig. 3 shows a calibration flowchart using the calibration device 10 of the present invention.

[0033] 1 (S11). A movement amount data acquisition unit 14 that acquires movement amount data from a GPS antenna is installed on the motor base 262. In this embodiment, a speedometer and distance meter that acquires GPS position information and measures traveling speed and traveled distance serves as the movement amount data acquisition unit 14 (S12). In addition, a rotation radius measurement PC 142 that acquires the traveling speed and traveled distance of the GPS antenna arranged on the detection unit fixing base 34 from the speedometer and calculates the trajectory of the circle is also installed on the motor base 262 (S12).

[0034] In step S13, a surveying instrument is used to set a predetermined distance between the rotation axis 22 and the detector fixing position 342. Here, the detector installed at the detector fixing position 342 is a GPS antenna. This predetermined distance serves as a reference distance for calibration and is compared with the turning radius value obtained from the minimum turning radius measuring device installed in steps S12 and S13. The reference distance is set to 5,000 m because the minimum turning radius of a standard-sized vehicle is approximately 5 m. However, it may be set to another distance depending on the size of the vehicle being measured by the minimum turning radius measuring device. Once the position of the rotation axis 22 and the detector fixing position 342 is determined, the rotation center 20, the rotating arm 30, and the rail 40 are fixed based on this position. A method for setting the reference distance between the rotation axis 22 and the detector fixing position 342 using a surveying instrument will be described in detail later.

[0035] In this specification, the minimum turning radius measuring device is configured by the speedometer and distance meter (movement amount data acquisition unit 14) equipped with a GPS antenna (detection unit) and the turning radius measurement PC 142, as described above.

[0036] The minimum turning radius measuring device is operated (S15), and calibration is started (S16).

[0037] First, a command is output from the remote PC 62 to the turntable control unit 66 to operate the motor 26 and rotate the turntable 24 to the left. The turntable control unit 66 is provided with a drive circuit for the motor 26, and rotates the rotating arm unit 30 including the detection unit fixing base 34 via the turntable 24 at an extremely slow speed defined in JIS D1025-1985 (S17).

[0038] Every time the detector fixing base 34 to which the GPS antenna is fixed makes one revolution, the PC 142 for measuring the radius of rotation measures the radius of rotation using the position information acquired from the GPS antenna (S18).

[0039] One lap is considered one test, and it is determined whether the required turning radius value has been obtained by turning the specified number of laps (S19). If the specified number of laps has not been reached, the process returns to step S18 and is repeated until the specified number is reached.

[0040] After the left turn test is completed by obtaining a predetermined number of turning radius values, the turning radius is measured in the opposite direction, that is, when the vehicle turns right.

[0041] A command is output from the remote PC 62 to the turntable control unit 66 to operate the motor 26 and rotate the turntable 24 to the right. The turntable control unit 66 rotates the rotating arm unit 30 including the detection unit fixing base 34 via the turntable 24 at an extremely slow speed defined by JIS D1025-1985 (S20).

[0042] As in the test for turning left, the turning radius is measured by the turning radius measuring PC 142 using the position information acquired from the GPS antenna each time the detector fixing base 34 to which the GPS antenna is fixed makes one revolution (S21).

[0043] One lap is considered one test, and it is determined whether the required turning radius value has been obtained by turning the specified number of laps (S22). If the specified number of laps has not been reached, the process returns to step S21 and is repeated until the specified number is reached.

[0044] When a predetermined number of turning radius values ​​are acquired and the right turn test is completed, the calibration is completed (S23).

[0045] The remote PC 62 acquires the data of the radius of rotation value from the PC for the radius of rotation via the wireless unit 64 and calculates the error from the reference distance. A calibration inspection report is created using the error value (S24). The calibration inspection report is output and an end process is performed (S25).

[0046] An example of an inspection report is shown in Figure 4. The inspection report includes the turning direction, turning number, turning speed, and turning radius. The turning speed is shown as the average speed (km / h) for each turn.

[0047] The turning radius section shows the reference distance, actual measurement value, error, average error, and accuracy. The reference distance is a predetermined distance value determined using a total station (described later). The actual measurement value is the distance between the rotation axis 22 and the GPS antenna measured by the minimum turning radius measuring device being measured by operating the calibration device 10 of the present invention and rotating the GPS antenna mounted on the detector fixing base 34 provided on the rotating arm unit 30. The error is the difference between the reference distance and the actual measurement value. The accuracy (%) is the error rate relative to the reference distance. The inspection report shown in Figure 4 is an example that shows only the inspection results; in addition to the results, at least the equipment being inspected, the inspector, the inspection date, the location, the specifications of the calibration device 10, and the test environment should also be shown.

[0048] In the calibration device 10 according to the present invention, the rail section 40, rotating arm section 30, and rotation center section 20 in an assembled state serve as the calibration reference devices. Therefore, it is necessary to set a reference distance and arrange the rail section 40, rotating arm section 30, and rotation center section 20 in a state in which the distance between the detection unit fixing position 342 and the rotation axis 22 on the circumference is accurately maintained at the reference distance. Below, we will describe a method for positioning the detection unit fixing position 342 on the rotating arm section 30 and the rotation axis 22 of the rotation center section 20 in accordance with the set reference distance, and then installing the rail section 40 accordingly.

[0049] FIG. 5 is a configuration diagram of the calibration device 10 according to the present invention when adjusting the reference distance. To adjust the reference distance, it is preferable to use a total station, which is a surveying instrument capable of measuring diagonal and horizontal distances with high accuracy, as the standard. In this case, it is preferable to use a prism-based total station, as it provides high accuracy. The total station used is one that has been calibrated and has guaranteed reliability. Note that the surveying instrument is not limited to a total station, and any instrument capable of accurately measuring horizontal distances will suffice. In this specification, a case where a total station is used as the surveying instrument will be described.

[0050] The calibration device 10 of the present invention is assembled without adjusting the reference distance. Next, the surveying instrument main body 50, i.e., the total station main body 50, is placed on the surveying instrument main body base 52. In addition, the total station target prism (hereinafter referred to as the target prism 54), which is the surveying instrument accessory 54, is placed on the accessory mounting base 562 of the accessory cart 56, which is composed of a base 566, an accessory mounting base 562, and an accessory mounting base support 564, and the accessory mounting base 562 is moved so that the target prism 54 is positioned directly above the detection unit fixing base 34. The base 566 is provided with base casters 568 so that it can be moved on the ground.

[0051] FIG. 6 shows a method for determining the fixed position 524 of the surveying instrument body. First, the fixed position 524 of the total station body is determined and fixed. The surveying instrument body base 52 is marked with a mark to indicate the center position of the rotation axis 22, or a hole is drilled so that the rotation axis 22 itself can be directly seen. When the total station body 50 is placed on the surveying instrument body base 52, it is confirmed that it is level. The total station body 50 is equipped with a telescope plummet 502. The intersection of the reticle visible when looking through the scope of the telescope plummet 502 is aligned with the center of the rotation axis 22, thereby aligning the survey reference point with the center of the total station. Once the fixed position 524 of the total station body is determined, the total station body 50 is installed on the surveying instrument body base 52 using screw fittings or other fasteners.

[0052] Next, the process of determining the detection unit fixing position 342 and attaching the GPS antenna will be described. A mark is provided on the detection unit fixing base 34 at the detection unit fixing position 342. When the target prism 54 is placed on the detection unit fixing base 34, it is confirmed that it is level. The target prism 54 is equipped with a laser light source that emits a laser beam RY, which indicates the reference point for surveying, directly below the target prism 54. The target prism 54 is moved so that the laser beam RY coincides with the mark provided at the detection unit fixing position 342. The total station is then operated to measure the distance between the rotation axis 22 and the detection unit fixing position 342.

[0053] FIG. 7 shows a method for determining the reference distance. A prism-based total station emits light from the total station main body 50 to a target prism 54, and measures distance based on the phase difference between the emitted light and the light that is reflected back to the total station main body 50. The oblique distance r between the rotation axis 22 and the detector fixed position 342 shown in FIG. 7 is measured. The angle θ of the emitted light or the returned light from the vertical or horizontal can be measured using the theodolite function of the total station. As a result, the vertical distance b and the horizontal distance a can be calculated using the equations b = r × sin θ and a = r × cos θ.

[0054] To improve the measurement accuracy, measurements are taken multiple times. The length of the rotating arm unit 30 is adjusted so that the measured horizontal distance a becomes a predetermined reference distance, for example, 5,000 m, and the rotating arm unit 30 is fixed to the turntable 24 of the rotation center 20.

[0055] Next, the GPS antenna is fixed to the detection unit fixing position 342, thereby completing the assembly and installation of the calibration device 10 according to the present invention. After the installation is complete, the total station main body 50 and the accessory cart 56 on which the target prism 54 is mounted are removed.

[0056] Thereafter, S15 in the calibration procedure flowchart of FIG. 3 is executed to start calibration and obtain the calibration results. [Industrial Applicability]

[0057] The calibration device of the present invention makes it possible to calibrate minimum turning radius measuring devices that do not actually trace a circular path using GPS or sensors. Furthermore, because the minimum turning radius of an automobile varies greatly depending on whether it is a large automobile, a standard automobile, or a compact automobile, the accuracy of the minimum turning radius measuring device can be accurately measured by changing the reference distance of the calibration device and performing calibration at a distance close to the minimum turning radius appropriate for each type of automobile. [Explanation of symbols]

[0058] 10. Calibration device for minimum turning radius measuring equipment (calibration device) 12 Movement amount detection unit 14. Movement data acquisition unit 142 Radius of rotation measurement computer (radius of rotation measurement PC) 20 Rotation center 22 Rotation axis 24 Turntable 26 Motor 262 Motor stand 264 Motor stand height adjuster 30 Rotating arm 32 Arm 34 Detector fixing stand 342 Detector fixed position 36 Detector unit fixing base support 38 Rotating arm caster 40 Rail section 42 Rail 44 Rail stand 442 Rail height adjuster 50 Surveying equipment main body (total station main body) 502 Telescope plummet 52 Surveying equipment main unit stand 522 Surveying equipment main body support 524 Fixed position of surveying equipment main body (fixed position of total station main body) 54 Surveying equipment accessories (target prism) 56 Accessory bogie 562 Accessory mounting stand 564 Accessory mounting support 566 Base 568 Base caster 60 Control section 62 Remote Computer (Remote PC) 64 Radio Section 66 Turntable control section 68 Control unit stand AX center axis EY Eyes GD ground RY laser light

Claims

1. A calibration device for a minimum turning radius measuring device that measures the minimum turning radius of a moving object by acquiring the amount of movement of the moving object using a satellite positioning system or a sensor, Arm and a detector fixing base for fixing a detector of the minimum turning radius measuring device fixed to one end of the arm; a rotation shaft that supports the arm so that it can rotate horizontally; Equipped with The detection unit The detector fixing table is disposed at a predetermined detector fixing position, The arm The detection unit is supported by the rotation shaft at a predetermined distance between the detection unit fixing position and the rotation shaft, rotating the rotation shaft at a predetermined speed, and calculating an error by comparing the radius of a circular locus calculated based on the amount of movement acquired from the detection unit with the predetermined length; A calibration device for a minimum turning radius measuring device, characterized by:

2. The preset length is The distance is measured using a calibrated surveying instrument and determined by supporting the arm and the rotation axis.

2. The calibration device for a minimum turning radius measuring instrument according to claim 1.

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