JP6738377B2 - Curvature information calculation device and autonomous vehicle including the same - Google Patents

Description

The present invention relates to a curvature information calculation device and an autonomous vehicle including the curvature information calculation device, and more particularly to a curvature information calculation device used when automatically traveling on a predetermined route and an automatic travel vehicle including the curvature information calculation device.

As an example of this type of conventional technology, Patent Document 1 discloses a road curvature detection device. In this device, the guide lines drawn on both sides of the vehicle on the road are imaged, and the tangents of the guide lines at points separated by a predetermined distance from the vehicle in the captured image are calculated for each of the guide lines on both sides. At the same time, the vehicle yaw angle, which is the traveling angle of the vehicle, is detected. Then, the curvature of the road on which the vehicle is traveling is calculated based on the calculated tangential data for the guide lines on both sides and the detected vehicle yaw angle data.

JP-A-7-19893

In order to calculate the curvature of the road with the road curvature detection device of Patent Document 1, it is necessary to capture an image of the guide lines drawn on both sides of the front of the vehicle on the road and calculate the tangents of the guide lines. The curvature cannot be calculated for roads without lines.

Therefore, a main object of the present invention is to provide a curvature information calculation device capable of calculating curvature information of a predetermined route regardless of the presence/absence of a guide line drawn on a road, and an autonomous vehicle including the curvature information calculation device. is there.

In order to achieve the above object, a storage unit that stores position information of a plurality of measurement points from a starting point in a predetermined route, and a measurement point group including three measurement points at a first predetermined interval from the plurality of measurement points. And a curvature information calculation unit that calculates curvature information regarding a curvature radius of an arc passing through the three measurement points based on position information of the three measurement points included in the extracted measurement point group. A calculation device is provided.

According to the present invention, the measurement point group including the three measurement points at the first predetermined interval is extracted from the plurality of measurement points stored in the storage unit. Then, based on the position information of the three measurement points included in the extracted measurement point group, the curvature information regarding the radius of curvature of the arc passing through the three measurement points is calculated. Therefore, the curvature information of the predetermined route can be calculated regardless of the presence or absence of the guide line drawn on the road.

Preferably, the curvature information calculation unit extracts a plurality of different measurement point groups from the plurality of measurement points and calculates curvature information for each of the extracted plurality of measurement point groups. In this case, the curvature information of the default route can be continuously obtained, and the shape of the default route can be easily grasped.

Further preferably, the curvature information calculation unit divides the predetermined route from the starting point at a second predetermined interval and averages the curvature radii of the measurement points belonging to the same section to calculate the curvature information of the same section. In this case, by averaging the curvature radii for each section, it is possible to obtain highly reliable curvature information for each section.

More preferably, there is provided an automatic traveling vehicle configured to be capable of automatically traveling on a predetermined route, the automatic traveling vehicle including a curvature information calculation device. In this case, the curvature information obtained by the curvature information calculation device can be used for controlling the autonomous vehicle.

Preferably, the storage unit stores the distance information regarding the distance from the starting point at each measurement point in association with the position information of each measuring point, and the automatic traveling vehicle further includes the traveling distance information regarding the traveling distance from the starting point to the current point. And a position detection unit that detects the position information of the current location by collating the travel distance information acquired by the travel distance acquisition unit with the distance information read from the storage unit. The curvature information calculation unit calculates the curvature information for the traveling area from the current point to the future, based on the position information from the current point to the future. In this case, the curvature information about the traveling area beyond the current point can be calculated during traveling. Therefore, it is not necessary to calculate the curvature information for the entire predetermined route in advance and store it in the storage unit, so that the amount of curvature information to be stored can be reduced.

Further, preferably, the position information and the distance information are obtained by traveling on a predetermined route in advance. In this case, the autonomous vehicle can obtain the position information and the distance information by traveling on the predetermined route in advance. The position information and the distance information can also be obtained by driving another vehicle of the same type as the autonomous vehicle.

More preferably, at each measurement point while traveling on the predetermined route, an image capturing unit that captures a predetermined direction as viewed from the autonomous vehicle, and a visual odometry method based on a plurality of image data captured by the image capturing unit. It further includes a position acquisition unit that acquires position information of the measurement point. In this case, it is possible to easily and accurately obtain the position information of each measurement point.

Preferably, a wheel for moving the autonomous vehicle, an angle detection unit for detecting the rotation angle of the wheel, and a distance acquisition unit for obtaining distance information of each measurement point based on the detection result of the angle detection unit. Further prepare. In this case, the distance information of each measurement point can be obtained easily and accurately.

Further preferably, the vehicle control device further includes a vehicle speed control unit that controls the vehicle speed of the traveling area from the current point on the basis of the curvature information calculated for the traveling area of the current point. In this case, the vehicle speed of the autonomous vehicle can be controlled based on the curvature information regarding the traveling area from the current location. Therefore, if there is a curve ahead, the automated vehicle can decelerate and travel along the curve according to the degree of bend of the curve, so that the lateral G applied to the automated vehicle can be suppressed and a comfortable ride for the occupant can be obtained.

More preferably, the vehicle speed control unit is based on a first determination unit that determines a first range in front of the autonomous vehicle based on an instruction vehicle speed to the autonomous vehicle, and a minimum value of curvature information within the first range. A second determining unit that determines the first target vehicle speed and a selecting unit that selects the smaller one of the instruction vehicle speed and the first target vehicle speed as the instruction vehicle speed are included. In this case, the first range in front of the autonomous vehicle is determined based on the instruction vehicle speed to the autonomous vehicle. For example, if the instructed vehicle speed increases, the first range also increases, and the search range for the minimum value of curvature information can be set appropriately. Then, the first target vehicle speed is determined based on the minimum value of the curvature information within the first range, and the smaller one of the instruction vehicle speed and the first target vehicle speed is selected as the target vehicle speed. As a result, the vehicle speed of the autonomous vehicle is controlled, and the lateral G applied to the autonomous vehicle can be suppressed.

Preferably, the vehicle speed control unit further includes a third determination unit that determines the second target vehicle speed based on the minimum value of the curvature information in the second range ahead of the first range, and the selection unit includes the instruction vehicle speed and the first vehicle speed. The minimum value of the first target vehicle speed and the second target vehicle speed is selected as the instruction vehicle speed. In this case, the second target vehicle speed is determined based on the minimum value of the curvature information in the second range ahead of the first range, and the minimum value among the commanded vehicle speed, the first target vehicle speed, and the second target vehicle speed is the target value. Is selected as the vehicle speed. In this way, by determining the target vehicle speed in consideration of the second range ahead of the first range, the vehicle speed of the autonomous vehicle is controlled, and the occupant can travel more comfortably.

Further preferably, the second determination unit weights the minimum value of the curvature information within the first range with the current value and the previous value, and determines the first target vehicle speed based on the weighted minimum value, The 3 determination unit weights the minimum value of the curvature information within the second range with the current value and the previous value, and determines the second target vehicle speed based on the weighted minimum value. In this case, noise of the minimum value of curvature information can be suppressed, and undesired deceleration can be prevented.

More preferably, the vehicle travels based on a magnetic field detection unit that detects a magnetic field from a guide wire provided on a predetermined route, a vehicle speed detection unit that detects a vehicle speed, and curvature information and the current vehicle speed detected by the vehicle speed detection unit. Whether or not to continue traveling of the autonomous vehicle based on whether or not the traveling duration has elapsed when the magnetic field from the guide line detected by the time calculating section and the magnetic field detecting section for calculating the duration is less than the threshold value. And a determination unit for determining whether or not. In this case, the running duration is calculated based on the curvature information and the current vehicle speed. Then, when the magnetic field from the guide wire provided on the predetermined route detected by the magnetic field detection unit is less than the threshold value, the traveling of the autonomous vehicle is continued until the traveling duration time elapses, and then stopped. As a result, even if there is a temporary power outage, a momentary disconnection of the guide wire, or a partial disconnection of the guide wire, it is possible to continue driving for the calculated travel duration and to drive immediately. You don't have to stop.

Preferably, the time calculation unit calculates the travelable distance until the magnetic field detection unit deviates from the range in which the magnetic field from the guide line can be detected based on the front and rear curvature information, and the current vehicle speed. A second calculation unit that calculates a stop distance that is a distance required for stopping based on the travel distance, a third calculation unit that calculates a travel continued distance based on the travelable distance and the stop distance, a travel continued distance and a current vehicle speed. And a fourth calculator that calculates the travel duration based on In this case, even if the magnetic field from the guide line detected by the magnetic field detection unit is less than the threshold value, the traveling is continued for the traveling duration time, and then the magnetic field detection unit detects the magnetic field from the guide line from the range in which the magnetic field can be detected. Driving can be stopped so as not to deviate. Therefore, when the traveling is resumed thereafter, the magnetic field detection unit can detect the magnetic field from the guide wire, so that the traveling can be resumed smoothly.

Also preferably, the running duration has an upper limit value. In this case, it is possible to suppress the automatic traveling vehicle from traveling for a long time in a state where the magnetic field from the guide wire detected by the magnetic field detection unit is less than the threshold value. It is effective when traveling on a straight road.

More preferably, a radio wave type detection unit that detects the presence of another vehicle by receiving a radio wave from another vehicle, a range setting unit that sets the detection range of the imaging unit, and a detection unit based on curvature information. And a sensitivity setting unit that sets the sensitivity of. For example, on a route with good visibility such as a curve with a small bend or a straight road, the detection range of the imaging unit can be made larger than the detection range of the detection unit, and the imaging unit can detect other vehicles more easily. On the other hand, for example, in the case of a curve with a bad turn and a large curve, other vehicles on the route may not be within the effective field of view of the imaging unit, and the detection unit may be easier to detect the other vehicle. Therefore, when the curvature information indicates that the degree of bend is small, the image pickup unit mainly performs the detection function of other vehicles by increasing the detection range of the image pickup unit, while the curvature information shows a large degree of bend. In that case, the detection unit mainly has a function of detecting another vehicle by appropriately setting the sensitivity of the detection unit. As a result, another vehicle can be satisfactorily detected regardless of the curvature information, and a good rear-end collision prevention function can be obtained.

Preferably, the sensitivity setting unit further sets the sensitivity of the detection unit based on the vehicle speed commanded to the autonomous vehicle. In this case, the sensitivity of the detection unit, that is, the detection range can be adjusted according to the instructed speed.

Further preferably, the sensitivity setting unit further sets the sensitivity of the detection unit based on the sensitivity switching instruction. In this case, the sensitivity of the detection unit, that is, the detection range can be adjusted according to the conditions of the predetermined route and the surrounding environment.

More preferably, it further includes a receiving unit that receives a sensitivity switching instruction transmitted by a transmitting member provided on the predetermined route. In this case, the sensitivity switching instruction can be easily and surely received.

The present invention can be suitably used for a golf cart.

According to the present invention, it is possible to calculate the curvature information of the predetermined route regardless of the presence or absence of the guide line drawn on the road.

It is an illustration figure which looked at the self-driving vehicle concerning one embodiment of this invention from the side. It is an illustration figure which looked at the automatic vehicle which concerns on one Embodiment of this invention from the front. It is a block diagram which shows the electric constitution of an automatic vehicle. It is an illustration figure which shows a predetermined route, a part of guide line and a measurement point, and a starting point. (A) And (b) is an illustration figure for demonstrating calculation of a curvature radius, (c) is an illustration figure for demonstrating calculation of an average curvature radius, (d) is an average curvature radius and CAN. It is a table which shows the relationship with the curvature information for transmission. It is a flow figure showing an example of operation which controls vehicle speed based on curvature information. 5 is a graph showing the relationship between the instructed vehicle speed and the first range. It is a circuit diagram which shows an IIR filter. (A) is a table showing the relationship between the curvature information in the first range and the first target speed, and (b) is a table showing the relationship between the curvature information in the second range and the second target speed. It is a graph which shows the relationship between a curvature radius and lateral G. It is an illustration figure which shows the positional relationship of a guidance sensor and a guidance wire. (A) is an illustrative view for explaining a method of calculating a travelable distance, and (b) is a table showing a relationship between a current vehicle speed and a stop distance. It is a flowchart which shows an example of the stop operation at the time of a momentary interruption. (A) is an illustration showing a case of a momentary break on a straight road, (b) is an illustration showing a case of a momentary break before entering a curve, and (c) is a momentary break in the middle of a unchanged curve. It is an illustration figure which shows a case, and (d) is an illustration figure which shows the case where there is a momentary break in the middle of a curve with a change. It is an illustration figure for demonstrating the detection range of a rear-end collision prevention sensor. It is an illustration figure for demonstrating a low sensitivity switching instruction. It is an illustration figure for demonstrating the detection range of an imaging part. It is a table for setting the detection range of the rear-end collision prevention sensor, (a) shows the case where the imaging unit function is on, and (b) shows the case where the imaging unit function is off. It is a table for setting the detection range of the imaging unit. It is a flowchart which shows an example of operation|movement of a rear-end collision prevention cooperation function. It is a flow figure showing an example of operation of fixed-point sensor detection processing. FIG. 22 is a flowchart showing a continuation of the operation of FIG. 21. It is a flowchart which shows an example of operation|movement of a rear-end collision prevention sensor reception sensitivity setting process. FIG. 24 is a flowchart showing a continuation of the operation in FIG. 23. It is an illustration figure for demonstrating the rear-end collision prevention function of an imaging part and a rear-end collision prevention sensor.

Embodiments of the present invention will be described below with reference to the drawings. Here, a case where the automatic vehicle 10 according to the embodiment of the present invention is applied to a golf cart will be described. In the following description, front-rear, left-right, and top-bottom refer to front-rear, left-right, and top-bottom with respect to a state in which an occupant is seated on the front seat portion 18 of the autonomous vehicle 10 toward the steering wheel 22.

1 and 2, the automatic vehicle 10 includes a frame portion 12, a pair of front wheels 14, a pair of rear wheels 16, a front seat portion 18, a rear seat portion 20, a steering wheel 22, and front pillars 24a, 24b. , Rear pillars 26a and 26b, and a roof portion 28.

The pair of front wheels 14 are rotatably supported by the front portion of the frame portion 12, and the pair of rear wheels 16 are rotatably supported by the rear portion of the frame portion 12. The front seat portion 18 and the rear seat portion 20 are supported by the frame portion 12 via a connecting member (not shown) or the like. A steering wheel 22 is provided in front of the front seat portion 18. Front pillars 24a and 24b are provided in front of the steering wheel 22, and rear pillars 26a and 26b are provided behind the rear seat portion 20. The lower ends of the front pillars 24a and 24b and the lower ends of the rear pillars 26a and 26b are supported by the frame unit 12. The roof portion 28 is supported by the front pillars 24a, 24b and the rear pillars 26a, 26b so as to cover the front seat portion 18, the rear seat portion 20, and the steering wheel 22 from above.

Further, referring to FIG. 3, the autonomous vehicle 10 includes a guidance sensor 30, a fixed point sensor 32, an imaging unit 34, a curvature information calculation device 36, a rotation angle sensor 38, a reception antenna 40, a transmission antenna 42, a rear-end collision prevention sensor 44, The steering unit 46, the drive unit 48, the brake unit 50, the battery 52, the control unit 54, and the storage unit 56 are included.

The induction sensor 30 is located in front of the front wheel 14, is attached to the front end of the frame portion 12 via the attachment bar 58, and can detect the magnetic field generated by the induction wire L (described later) provided on the predetermined path P. It is provided at the bottom of the vehicle body so as to face the ground. The inductive sensor 30 includes sensor units 30a, 30b and 30c. The sensor units 30a, 30b, and 30c are provided on the lower surface of the mounting bar 58 at the center, left side, and right side in the left-right direction, respectively.

The fixed point sensor 32 is located slightly behind the front wheel 14, is attached to the frame portion 12, and is fixed to the vehicle body so as to face the ground so that a signal from a fixed point member 60 (described later) provided on the predetermined path P can be read. It is provided at the bottom. The fixed point sensor 32 includes a main sensor part 32a and a sub sensor part 32b arranged side by side, and the main sensor part 32a is provided inside and the sub sensor part 32b is provided outside.

The imaging unit 34 is, for example, a stereo camera including left and right image sensors 34a and 34b, and is provided at the front end of the upper surface of the roof 28 and at the center in the left-right direction. The image sensors 34a and 34b are composed of general visible light sensors such as CCD (Charge-Coupled Device) and CMOS (Complementary MOS). The imaging data from the imaging unit 34 is input to the curvature information calculation device 36.

The curvature information calculation device 36 includes a control unit 36a and a storage unit 36b. The control unit 36a includes, for example, a CPU and performs image processing, calculation of front curvature information, and the like. The storage unit 36b is composed of, for example, a memory or a hard disk. The storage unit 36b stores position information, distance information, a table shown in FIG.

The rotation angle sensor 38 detects the rotation angle of the wheel, and is formed of, for example, a rotary encoder, and is provided on the right front wheel 14.

The receiving antenna 40 is provided at the frame portion 12 and thus at the front end portion of the vehicle body so as to be able to receive radio waves from the vehicle in front. The transmitting antenna 42 is provided on the frame portion 12 and thus on the rear end portion of the vehicle body so that radio waves can be transmitted to the rear vehicle. The rear-end collision prevention sensor 44 is a radio wave type sensor, and determines whether or not there is a vehicle ahead based on the radio wave from the reception antenna 40.

The steering unit 46 includes the steering wheel 22, is connected to the pair of front wheels 14, and steers the pair of front wheels 14 . The drive unit 48 includes, for example, an engine and drives the pair of front wheels 14 and/or the pair of rear wheels 16. The brake unit 50 brakes the pair of front wheels 14 and/or the pair of rear wheels 16. The battery 52 is, for example, a 12V battery, and supplies power to the curvature information calculation device 36 and the control unit 54.

The control unit 54 includes, for example, a CPU, and the storage unit 56 includes, for example, a memory and a hard disk. The storage unit 56 stores the graph shown in FIG. 7, the data of the tables shown in FIGS. 9, 18, and 19, the programs for performing the operations shown in FIGS. 6, 13, and 20 to 24. To be done. Signals and information from the guidance sensor 30, the fixed point sensor 32, the curvature information calculation device 36, the rotation angle sensor 38, and the rear-end collision prevention sensor 44 are input to the control unit 54. Based on these signals and information, the control unit 54 instructs the steering unit 46, the drive unit 48, and the brake unit 50 to control the steering, vehicle speed, drive, braking, stop, etc. of the autonomous vehicle 10, and the image capturing unit. 34, and the detection range of the rear-end collision prevention sensor 44.

With reference to FIG. 4, such an automatic vehicle 10 automatically travels along a guide line L provided at the center of a predetermined route P. The guide wire L is embedded in the ground of the predetermined route P, and the guide sensor 30 receives the magnetic field generated by the guide wire L and outputs a detection signal to the control unit 54. The control unit 54 controls the steering unit 46 so that the guide wire L is within 15 cm in the left-right direction from the center of the sensor unit 30a. Further, the left sensor unit 30b and the right sensor unit 30c detect whether the autonomous vehicle 10 is biased leftward or rightward, and the control unit 54 determines the sensor unit of the autonomous vehicle 10 based on the detection result. The steering unit 46 is controlled so that 30a approaches the guide line L. As a result, the autonomous vehicle 10 automatically travels on the predetermined route P.

Referring to FIGS. 4 and 16, fixed point members 60 are embedded along guide line L at a plurality of predetermined positions including starting point C0. The fixed point member 60 is composed of, for example, a combination of a plurality of magnets, and is composed of five magnets like the magnets 60a to 60e in this embodiment. The fixed point sensor 32 is configured to be able to read magnetic pole information from the fixed point member 60, and is composed of, for example, a magnetic pole sensor. The fixed point member 60 transmits, for example, an instruction signal for instructing the instruction vehicle speed to the automatic traveling vehicle 10 and an instruction signal for instructing the sensitivity switching of the rear-end collision prevention sensor 44. When the autonomous vehicle 10 passes over the fixed point member 60, the fixed point sensor 32 receives the instruction signal from the passed fixed point member 60 and outputs the instruction signal to the control unit 54. The control unit 54 controls the traveling, stop, deceleration, etc. of the autonomous vehicle 10 and the sensitivity switching of the rear-end collision prevention sensor 44 according to the instruction signal.

Further, the fixed point sensor 32 outputs information to that effect to the control unit 54 when the autonomous vehicle 10 passes through the fixed point member 60. The control unit 54 measures the distance traveled after passing through the fixed point member 60 based on the information about the rotation angle of the wheel output from the rotation angle sensor 38 with reference to the time point when the fixed point member 60 is passed. If the control unit 54 stores information about the diameter of the right front wheel 14 in the storage unit 56 in advance, the control unit 54 determines a predetermined time point based on the rotation angle (rotation speed) and the diameter of the front wheel 14 from the predetermined time point. It is possible to calculate the mileage of the autonomous vehicle 10 from. Therefore, the control unit 54 can measure the traveling distance from the starting point C0 to the current point by using the time point when the starting point C0 has passed as a reference.

The position information and the distance information stored in the storage unit 36b are generated by the control unit 36a of the curvature information calculation device 36 when the autonomous vehicle 10 travels on the predetermined route P in advance.

When creating the position information, first, while the automatic traveling vehicle 10 travels on the predetermined route P, the imaging unit 34 continuously captures images of the front of the automatic traveling vehicle 10 at a predetermined frame rate. Thereby, the imaging data can be obtained by the imaging unit 34 for each of the plurality of measurement points.

Next, the control unit 36a calculates the position of the autonomous vehicle 10 and the orientation of the vehicle body based on the plurality of imaged data obtained by the imager 34. As this calculation method, for example, a method of visual odometry can be used. As a specific example, it is performed by the control unit 36a extracting a plurality of feature points on the imaged data and detecting the displacement of each feature point on two consecutive imaged data. As a result, the amount of change in the position and the amount of change in the direction of the autonomous vehicle 10 between the two pieces of image data are calculated.

Then, with the starting point C0 as the origin, the calculated change amount is sequentially added from the starting point C0, whereby a total of six components (x coordinate, y coordinate, z coordinate, roll angle, pitch angle, The position information at the measurement point composed of the yaw angle) is acquired. In this way, the control unit 36a creates the position information of the autonomous vehicle 10 over the entire predetermined route P and stores it in the storage unit 36b.

In addition, the control unit 36a measures the position information of the automatic traveling vehicle 10 at each point where each image of the front of the automatic traveling vehicle 10 is captured by the image capturing unit 34, that is, each measurement point, and each measurement from the starting point C0 sent from the control unit 54. The distance information regarding the distance traveled by the autonomous vehicle 10 up to the point is associated and stored in the storage unit 36b.

For example, the automatic traveling vehicle 10 travels on the predetermined route P, and the imaging unit 34 images the front of the automatic traveling vehicle 10 at a frame rate of 30 times per second in the traveling area beyond the starting point C0 of the predetermined route P. In this case, the distance between the adjacent measurement points varies depending on the vehicle speed of the autonomous vehicle 10, and the imaging data and thus the position information is obtained for each measurement point along the predetermined route P, and the distance information regarding the travel distance is obtained. .. Then, the position information and the distance information for each measurement point are linked and stored in the storage unit 36b. In this way, the storage unit 36b stores position information and distance information of a plurality of measurement points from the starting point C0 on the predetermined route P.

After the pre-processing as described above is performed, during the actual traveling, the curvature information calculation device 10 obtains the curvature information of the predetermined route P in front of the autonomous vehicle 10 as follows.

First, the control unit 54 calculates the travel distance information regarding the travel distance from the starting point C0 to the current point based on the output from the rotation angle sensor 38 while the automatic traveling vehicle 10 is traveling on the predetermined route P, and the curvature information. It is output to the control unit 36a of the calculation device 36.

The control unit 36a collates the traveling distance information with the distance information read from the storage unit 36b, and detects the position information of the current position of the automatic vehicle 10 associated with the distance information. At this time, the position information is detected with the measurement point of the distance information having the closest traveling distance information as the current point of the autonomous vehicle 10.

The control unit 36a calculates the curvature information about the traveling area from the current point onward based on the position information on the current point ahead. At this time, the control unit 36a extracts a measurement point group including three measurement points at a first predetermined interval from the plurality of measurement points. For example, a measurement point group consisting of three measurement points is extracted at 2.5 m intervals. In this case, the first predetermined interval is 2.5 m.

Then, the control unit 36a calculates the radius of curvature of an arc passing through the three measurement points based on the position information of the three measurement points included in the extracted measurement point group. With reference to FIG. 5A, perpendicular bisectors B1 and B2 are drawn for line segments A1 and A2 that connect adjacent measurement points, and an intersection O is obtained. The intersection O becomes the center of a circle passing through the three measurement points, and the distance r between the intersection O and each measurement point becomes the radius of the circle, that is, the radius of curvature. The radius of curvature can be calculated using the two-dimensional plane coordinates (x coordinate, y coordinate) of the position information of the measurement point.

With reference to FIG. 5A, such calculation of the radius of curvature is performed by first setting the measurement point at the current position of the autonomous vehicle 10 as the measurement point of the first frame, and the measurement point of the first frame and the measurement point of the second frame. It is performed for a measurement point group consisting of a measurement point 5 m ahead and a measurement point 5 m ahead. Then, with reference to FIG. 5B, the measurement points are shifted frame by frame until the measurement point 5 m ahead reaches the 1024th frame, for a total of 1022 measurement point groups.

Then, with reference to FIG. 5C, the predetermined route P is divided at intervals of 2 m from the measurement point of the first frame to 20 m ahead, the radii of curvature belonging to each section are averaged, and the average radius of curvature is obtained at intervals of 2 m. .. The section to which the measurement point closest to the starting point C0 among the three measurement points belongs is defined as the section to which the radius of curvature obtained from the three measurement points belongs. The control unit 36a converts the obtained average radius of curvature into 16-step CAN transmission curvature information based on the table shown in FIG. 5D, and stores it in the storage unit 36b. In this example, the 2m interval corresponds to the second predetermined interval. The autonomous vehicle 10 repeats the above-described processing while traveling on the predetermined route P to obtain curvature information.

In this way, the control unit 36a extracts a plurality of different measurement point groups from the plurality of measurement points, and calculates the curvature radius as the curvature information for each of the extracted plurality of measurement point groups. Then, the control unit 36a divides the predetermined route P at the second predetermined interval, averages the radii of curvature of the measurement points belonging to the same section, and calculates the average radius of curvature as the curvature information of the same section.

According to the autonomous vehicle 10 including such a curvature information calculation device 36, the measurement point group including three measurement points at the first predetermined interval is extracted from the plurality of measurement points stored in the storage unit 36b. It Then, based on the position information of the three measurement points included in the extracted measurement point group, the curvature information regarding the radius of curvature of the arc passing through the three measurement points is calculated. Therefore, the curvature information of the predetermined route P can be calculated regardless of the presence or absence of the guide line drawn on the road.

The curvature information is calculated for each of the plurality of extracted measurement point groups. Therefore, the curvature information of the predetermined route P can be continuously obtained, and the shape of the predetermined route P can be easily grasped.

By averaging the curvature radii for each section, highly reliable curvature information can be obtained for each section.

It is possible to calculate the curvature information about the traveling area from the current position when traveling. Therefore, since it is not necessary to previously calculate the curvature information for the entire area of the predetermined route P and store it in the storage unit 36b, the amount of curvature information to be stored can be reduced.

Position information and distance information can be obtained by the automatic traveling vehicle 10 traveling on the predetermined route P in advance. The position information and the distance information can also be obtained by driving another vehicle of the same type as the autonomous vehicle 10.

The position information of each measurement point is obtained by the method of visual odometry based on the plurality of imaged data captured by the imager 34. Therefore, the position information of each measurement point can be obtained easily and accurately.

Distance information of each measurement point is obtained based on the detection result of the rotation angle sensor 38. Therefore, the distance information of each measurement point can be obtained easily and accurately.

The curvature information obtained in this manner can be used for control of the automatic traveling vehicle 10, such as the vehicle speed of the automatic traveling vehicle 10, the stopping operation when a momentary interruption occurs, and the operation of the rear-end collision prevention cooperation function.

In this embodiment, the control unit 36a corresponds to the curvature information calculation unit, the position detection unit, and the position acquisition unit. The rotation angle sensor 38 corresponds to the angle detection unit. The control unit 54 includes a distance acquisition unit, a vehicle speed control unit, a first determination unit, a second determination unit, a third determination unit, a selection unit, a time calculation unit, a determination unit, a first calculation unit, a second calculation unit, and a second calculation unit. It corresponds to the third calculation unit, the fourth calculation unit, the range setting unit, and the sensitivity setting unit. The induction sensor 30 corresponds to the magnetic field detection unit. The rear-end collision prevention sensor 44 corresponds to the detection unit. The fixed point member 60 corresponds to the transmitting member. The fixed point sensor 32 corresponds to the receiving unit. The travel distance acquisition unit includes the rotation angle sensor 38 and the control unit 54. The vehicle speed detection unit includes a rotation angle sensor 38 and a control unit 54.

An operation of controlling the vehicle speed of the autonomous vehicle 10 based on the curvature information will be described with reference to FIG. The operation shown in FIG. 6 is repeated in a cycle of 20 msec.

First, the control unit 54 acquires the first range in front of the autonomous vehicle 10 based on the instruction vehicle speed (step S1). The first range is determined based on the data showing the relationship between the instructed vehicle speed and the first range shown in FIG. 7.

The control unit 54 searches for and selects the minimum value of the curvature information within the first range (the average radius of curvature also becomes the minimum value) from the curvature information up to 20 m ahead transmitted from the control unit 36 a by CAN communication. (Steps S3 to S7). Here, the minimum value included in the first range is selected from the data converted into the 16-step curvature information based on the table shown in FIG.

The control unit 54 weights the minimum value of the selected curvature information by the previous value (step S9). In this embodiment, the processing of the IIR filter shown in FIG. 8 is performed by the control unit 54. That is, the minimum value of the curvature information selected this time is 5%, and the value of (after IIR filter processing) obtained by the previous weighting is added at a rate of 95% to obtain the minimum value of the curvature information after weighting. ..

Then, the control unit 54 searches for and selects the minimum value of the curvature information within the second range (steps S11 to S15). Here, the area ahead of the first range and up to 20 m ahead of the autonomous vehicle 10 is the second range, and is the second of the data converted into 16 levels of curvature information based on the table shown in FIG. The smallest value included in the range is selected.

The control unit 54 weights the minimum value of the selected curvature information by the previous value (step S17). In this embodiment, similarly to step S9, the processing of the IIR filter shown in FIG. 8 is performed by the control unit 54. That is, the minimum value of the curvature information selected this time is 5%, and the value of (after IIR filter processing) obtained by the previous weighting is added at a rate of 95% to obtain the minimum value of the curvature information after weighting. ..

Then, the control unit 54 calculates the first target vehicle speed in the first range based on the minimum value of the curvature information obtained in step S9 (step S19), and sets it to the minimum value of the curvature information obtained in step S17. Based on this, the second target vehicle speed in the second range is calculated (step S21). Here, the first target vehicle speed is obtained based on the table shown in FIG. 9A, and the second target vehicle speed is obtained based on the table shown in FIG. 9B.

The control unit 54 compares the first target vehicle speed and the second target vehicle speed (step S23), and if the second target vehicle speed is small, sets the second target vehicle speed as the target vehicle speed (step S25), otherwise, the first target vehicle speed. The vehicle speed is set as the target vehicle speed (step S27). Further, the control unit 54 compares the instructed vehicle speed with the target vehicle speed (step S29), and if the target vehicle speed is small, sets the target vehicle speed as the instructed vehicle speed (step S31). .. The control unit 54 controls the vehicle speed of the autonomous vehicle 10 based on the instruction vehicle speed obtained in steps S29 and S31.

According to such an operation, the vehicle speed of the autonomous vehicle 10 can be controlled based on the curvature information in the traveling area beyond the current location. Therefore, if there is a curve ahead, the automatic vehicle 10 can decelerate and travel along the curve according to the degree of bending of the curve, so that the lateral G applied to the automatic vehicle 10 can be suppressed and a comfortable ride for the occupant can be obtained. To be

The first range in front of the autonomous vehicle 10 is determined based on the vehicle speed commanded to the autonomous vehicle 10. For example, if the instructed vehicle speed increases, the first range also increases, and the search range for the minimum value of curvature information can be set appropriately. Then, the first target vehicle speed is determined based on the minimum value of the curvature information within the first range, and the second target vehicle speed is determined based on the minimum value of the curvature information within the second range ahead of the first range. .. The minimum value among the instructed vehicle speed, the first target vehicle speed, and the second target vehicle speed is selected as the target vehicle speed. Thereby, the lateral G applied to the autonomous vehicle 10 can be suppressed. As shown in FIG. 10, even if the radius of curvature of the predetermined route P changes, the lateral G applied to the autonomous vehicle 10 is stable. In addition, by determining the target vehicle speed in consideration of the second range ahead of the first range, the vehicle speed of the autonomous vehicle 10 is controlled, and the occupant can travel more comfortably.

The first target vehicle speed is determined based on the minimum value of the weighted curvature information within the first range, and the second target vehicle speed is determined based on the minimum value of the weighted curvature information within the second range. Therefore, noise of the minimum value of the curvature information can be suppressed, and undesired deceleration can be prevented.

Next, the stop operation of the automatic vehicle 10 when a momentary interruption occurs will be described.

In an automatic vehicle that controls the steering so that it travels along the guide line by detecting the magnetic field generated by the guide line, conventionally, if the magnetic field from the guide line disappears due to a momentary interruption, the steering cannot be controlled. , The steering was turned off (while maintaining the steering angle), and the vehicle immediately entered the stop mode.

Referring to FIG. 11, in the automatic vehicle 10, even when the magnetic field from the guide line L cannot be detected, the distance between the central sensor unit 30a of the guide sensor 30 and the guide line L in the left-right direction is the set distance d. You can continue running until it reaches (±15 cm).

Here, the traveling continuation distance and the traveling continuation time are calculated as follows.

With reference to FIG. 12A, the distance between the sensor unit 30 a and the guide line L in the left-right direction is based on the radius of curvature before the occurrence of the instantaneous interruption and the average radius of curvature of the section 0-2 m ahead of the autonomous vehicle 10. The travelable distance A at which the vehicle can travel until the set distance d is calculated.

In FIG. 12(a), A is the travelable distance, d is the set distance, R is the radius of curvature before the occurrence of the instantaneous interruption (the route the vehicle is going to travel) (dashed line), and R'is the average of the 0-2m section. The radius of curvature (solid line), a indicates the angle R-R', and θ indicates the angle R-d.

According to the cosine theorem, cos θ is calculated by the following formula, and therefore the travelable distance A is calculated by the following formula.

cos θ=|(2aR-2dR+d ² )/2a(R−d)|

θ=ArcCos{|(2aR-2dR+d ² )/2a(R−d)|}

A=θR

The stop distance B, which is the distance required for stopping, is calculated based on the current vehicle speed with reference to the table shown in FIG.

The travel continued distance is calculated by (travel continued distance=travelable distance A−stop distance B).

The running duration is calculated by (running duration=running distance/current vehicle speed).

With reference to FIG. 13, the stop operation of the automatic vehicle 10 at the time of a momentary interruption will be described. The operation shown in FIG. 13 is repeated in a cycle of 20 msec.

First, the control unit 54 determines whether the detection voltage of the inductive sensor 30 is less than 0.5V (step S101). Thereby, it is determined whether the magnetic field from the guide line L detected by the guide sensor 30 is less than the threshold value. If the detected voltage is 0.5 V or more, no instantaneous interruption has occurred, and the control unit 54 determines the travelable distance based on the radius of curvature before the occurrence of the instantaneous interruption and the average radius of curvature of the section 0-2 m ahead. Is calculated (step S103). Here, the radius of curvature obtained in step S119 described below is used as the radius of curvature before the occurrence of the instantaneous interruption, and the radius of curvature 0-2 m transmitted from the curvature information calculation device 36 is used as the average radius of curvature of the region 0-2 m. The average radius of curvature of the section is used, and the travelable distance is calculated by the above formula. As a result, the travelable distance until the guidance sensor 30 deviates from the range in which the magnetic field from the guidance line L can be detected is calculated based on the front and rear curvature information. Next, the control unit 54 refers to the table shown in FIG. 12B, calculates the stop distance based on the current vehicle speed (step S105), subtracts the stop distance from the travelable distance, and calculates the travel continued distance. Is obtained (step S107). The control unit 54 calculates the vehicle speed based on the output from the rotation angle sensor 38 and the required time.

Then, the control unit 54 determines whether or not the traveling continuation distance is 0 or less (step S109), and if the traveling continuation distance is 0 or less, sets the traveling continuation distance to 0 (step S111) and proceeds to step S113. .. In step S109, if the travel continued distance is greater than 0, the process proceeds to step S113. In step S113, the control unit 54 calculates (travel continued distance/current vehicle speed) to calculate the travel continued time. Then, the control unit 54 determines whether or not the traveling duration is longer than 500 msec (step S115). If the traveling duration is longer than 500 msec, the control unit 54 sets the traveling duration to the upper limit value of 500 msec (step S117), and proceeds to step S119. Before the occurrence of a momentary interruption, the running duration is calculated based on the running distance and the current vehicle speed, and a timer is set.For example, in the case of a straight road, the calculated running duration, and thus the running duration, becomes longer and Since the vehicle may be able to travel for hours, the upper limit value of the traveling duration is set to 500 msec. If the traveling duration is 500 msec or less in step S115, the process proceeds to step S119. In step S119, the control unit 54 sets the radius of curvature in the section 0-2m to the radius of curvature before the occurrence of the instantaneous interruption, and ends the process.

On the other hand, in step S101, if the detected voltage is less than 0.5 V, it is determined that the instantaneous interruption has occurred, and the control unit 54 sets the radius of curvature before the occurrence of the instantaneous interruption and the average radius of curvature in the section 0-2 m ahead. Based on this, the travelable distance is calculated (step S121). The travelable distance is calculated by the above formula. Then, the control unit 54 determines whether the calculated travelable distance is smaller than the previous value (step S123), and if the calculated travelable distance is smaller than the previous value, the control unit 54 determines the travelable distance. It is updated (step S125), and the process proceeds to step S127. In this way, the travelable distance is updated to a smaller value after the occurrence of the instantaneous interruption. If the travelable distance is equal to or greater than the previous value in step S123, the process proceeds to step S127. In step S127, the control unit 54 refers to the table shown in FIG. 12B to calculate the stop distance based on the current vehicle speed. Then, the control unit 54 subtracts the stop distance from the travelable distance to obtain the travel continuation distance (step S129).

Then, the control unit 54 determines whether the traveling continuation distance is 0 or less (step S131), and if the traveling continuation distance is 0 or less, the control unit 54 sets the traveling continuation distance to 0 (step S133). , And proceeds to step S135. In step S131, if the traveling continuation distance is greater than 0, the process proceeds to step S135. In step S135, the control unit 54 determines whether the traveling continuation time is 20 msec or more. If the traveling duration is 20 msec or more, the control unit 54 subtracts 20 seconds from the traveling duration (step S137), and proceeds to step S139. Thus, when a momentary interruption occurs, 20 msec is subtracted for each cycle of the operation shown in FIG. If the traveling duration is less than 20 msec in step S135, the process proceeds to step S139. In step S139, the control unit 54 determines whether the traveling duration is 0 or less. When the traveling duration is 0 or less, the control unit 54 determines that the vehicle is stopped and shifts to the stop mode so that the guide line L and the sensor unit 30a of the guide sensor 30 are not separated from each other by the set distance d (step S). S141). On the other hand, if the travel continued distance is greater than 0, the control unit 54 determines that the travel is continued and remains in the travel continued mode (step S143), and ends.

According to such an operation, the traveling duration is calculated based on the curvature information and the current vehicle speed. Then, when the magnetic field from the guide line L provided on the predetermined route P detected by the guide sensor 30 is less than the threshold value, the traveling of the autonomous vehicle 10 is continued until the traveling duration time elapses, and then stopped. As a result, even if there is a temporary power outage, a momentary disconnection of the guide wire, or a partial disconnection of the guide wire, it is possible to continue driving for the calculated travel duration and to drive immediately. You don't have to stop.

Even if the magnetic field from the guide line L detected by the guide sensor 30 is less than the threshold value, the traveling is continued for the traveling duration time, and then the guide sensor 30 deviates from the range in which the magnetic field from the guide line L can be detected. You can stop running so as not to. Therefore, when the traveling is resumed thereafter, the guidance sensor 30 can detect the magnetic field from the guidance line L, so that the traveling can be resumed smoothly.

Since the traveling duration has an upper limit value, it is possible to prevent the autonomous traveling vehicle 10 from traveling for a long time in a state where the magnetic field from the guide line L detected by the guidance sensor 30 is less than the threshold value. It is effective when traveling on a straight road.

For example, as shown in FIG. 14(a), when there is a momentary disconnection on the straight line of the preset route P, the steering is turned off (the steering angle is maintained). When 500 msec has elapsed, the stop mode is entered, and then the autonomous vehicle 10 stops. As shown in FIG. 14( b ), when there is a momentary break before entering a curve on a straight road of a predetermined route P, the steering is turned off, so the vehicle continues straight ahead and the guide line L and the sensor unit 30 a of the guide sensor 30 are set. The autonomous vehicle 10 is stopped so as not to be separated from the distance d. As shown in FIG. 14C, when there is a momentary break in the curve on which the radius of curvature does not change in the predetermined route P, the steering is turned off, so the vehicle turns along the predetermined route P as it is, and the traveling duration is 500 msec. After a lapse of time, the stop mode is entered, and then the autonomous vehicle 10 is stopped. When there is a momentary interruption in the middle of a curve having a change in the radius of curvature in the predetermined route P as shown in FIG. 14D (a curve in which the radius of curvature before occurrence of the momentary interruption differs from the average radius of curvature in the 0-2 m section) Since the steering is turned off, the vehicle is turned in a direction different from the curve, and the autonomous vehicle 10 is stopped so that the guide line L and the sensor unit 30a of the guide sensor 30 are not separated from each other by the set distance d.

Further, the rear-end collision prevention cooperation function of the autonomous vehicle 10 will be described.

The autonomous vehicle 10 has a rear-end collision prevention function using the rear-end collision prevention sensor 44. Referring to FIGS. 15(a) and 15(b), in automatic vehicle 10, when reception antenna 40 receives a radio wave of a predetermined frequency transmitted from the transmission antenna of the vehicle ahead, it is given to rear-end collision prevention sensor 44. The rear-end collision prevention sensor 44 compares the input radio wave with a voltage threshold value, and if the radio wave is larger than the voltage threshold value, detects that there is a vehicle ahead.

The rear-end collision prevention sensor 44 has three sensitivities: low sensitivity, medium sensitivity, and high sensitivity. For example, the low sensitivity detection range is 1.8±0.15 m, the medium sensitivity detection range is 3.8±0.15 m, and the high sensitivity detection range is 4.2±0.15 m. The sensitivity and thus the detection range can be adjusted by switching the voltage threshold of the rear-end collision prevention sensor 44, and the sensitivity increases as the voltage threshold decreases. In this embodiment, the detection range refers to the maximum distance from the reception antenna 40 to the transmission antenna of the vehicle ahead when the rear-end collision prevention sensor 44 can detect the vehicle ahead.

The instruction to switch the rear-end collision prevention sensor 44 to the low sensitivity is performed as follows, for example.

Referring to FIG. 16, fixed point member 60 including five magnets 60a to 60e is embedded in the ground along guide line L of predetermined path P, and the surfaces of magnets 60a to 60c are N poles. Thus, the magnets 60d and 60e are provided so that the surfaces thereof are S poles. The magnets 60a to 60d are main magnets, and the magnet 60e is a sub magnet. When the autonomous vehicle 10 travels along the guide line L, the main sensor portion 32a of the fixed-point sensor 32 detects the magnetic poles of the magnets 60a to 60d in this order, and the sub sensor portion 32b detects the magnetic pole of the magnet 60e. By doing so, the automated vehicle 10 receives the low sensitivity switching instruction, and the sensitivity of the rear-end collision prevention sensor 44 is switched to the low sensitivity.

Further, with reference to FIG. 17A, the autonomous vehicle 10 has a rear-end collision prevention function using the image capturing unit 34. In the autonomous vehicle 10, the imaging unit 34 provided at the front end of the roof portion 28 images the front of the autonomous vehicle 10 and can detect an obstacle (vehicle in front) on the predetermined route P. The detection range required by the imaging unit 34 is determined based on the curvature information, and is set, for example, in front of the autonomous vehicle 10 at a maximum of 10 m. Further, as shown in FIG. 17B, the width of the predetermined route P can be detected by the imaging unit 34.

18A and 18B are tables for setting the detection range of the rear-end collision prevention sensor 44. FIG. 18A shows a case where the imaging unit function is turned on, and the sensitivity of the rear-end collision prevention sensor 44 is set to low sensitivity or medium sensitivity based on the curvature information and the low sensitivity switching flag, and the detection range is set accordingly. To be done. When the function of the imaging unit is on, high sensitivity is invalid. Further, when the instructed vehicle speed is 3.6 km/h, the sensitivity becomes low. FIG. 18B shows the case where the function of the imaging unit is off, and the sensitivity of the rear-end collision prevention sensor 44 is set to low sensitivity, medium sensitivity or high sensitivity based on the instructed vehicle speed.

FIG. 19 is a table for setting the detection range of the imaging unit 34. FIG. 19 shows the instruction vehicle speed for the curvature information, the detection range of the image pickup unit 34, and the detectable range of the image pickup unit 34. Here, the detection range refers to a range that the imaging unit 34 needs to detect, and the detectable range refers to a range that the imaging unit 34 can detect. When the curvature information is 2 or 3 (the radius of curvature is more than 6 m and 10 m or less), the detectable range of the imaging unit 34 becomes the detection range or less, and therefore the rear-end collision prevention sensor 44 is set to the middle regardless of whether the low sensitivity switching flag is on or off. Set to sensitivity (see FIG. 18). When the curvature information is 1 or less (the curvature radius is 6 m or less), the instructed vehicle speed is 3.6 km/h, and the rear-end collision prevention sensor 44 can be sufficiently stopped with low sensitivity. Therefore, at this time, in the imaging unit 34, there is no problem even if the detectable range falls below the detectable range.

With reference to FIGS. 20 to 24, the rear-end collision prevention cooperation function of the autonomous vehicle 10 will be described. The operation shown in FIGS. 20 to 24 is repeated in a cycle of 20 msec.

The overall operation of the rear-end collision prevention cooperation function will be described with reference to FIG.

First, the control unit 54 acquires curvature information from the curvature information calculation device 36 based on CAN information (step S201). When the reception is successful, the rear-end collision prevention function of the image pickup unit 34 is turned on.

Next, the control unit 54 refers to the detection range switching table shown in FIG. 19 and sets the detection range of the imaging unit 34 based on the instructed vehicle speed (step S203). In other words, the detection range of the imaging unit 34 can be set based on the radius of curvature and thus the curvature information. The control unit 54 instructs the detection range of the imaging unit 34 through the curvature information calculation device 36.

Next, the control unit 54 performs fixed point sensor detection processing (step S205). At this time, the reception sensitivity of the rear-end collision prevention sensor 44 is instructed by the fixed point member 60. Details of the operation will be described later.

Then, the control unit 54 changes the instructed vehicle speed and determines the current curvature information by the vehicle speed control process described above with reference to FIG. 6 (step S207). The current curvature information is the curvature information obtained in step S9 of the vehicle speed control operation shown in FIG.

Further, the control unit 54 performs the reception sensitivity setting process of the rear-end collision prevention sensor 44 based on the curvature information, the instructed vehicle speed, and the reception sensitivity instruction (step S209). Details of the operation will be described later.

The fixed point sensor detection processing will be described with reference to FIGS. 21 and 22.

First, the control unit 54 determines whether or not the main sensor unit 32a of the fixed-point sensor 32 detects the main magnet (step S301). If the main magnet is detected, the control unit 54 determines that the polarity of the main magnet is S. It is determined whether it is a pole (step S303). If it is the S pole, the current fixed point information is set to S (step S305), while if it is the N pole, the current fixed point information is set to N (step S307), and the process proceeds to step S309. Even when the main magnet is not detected in step S301, the process proceeds to step S309.

In step S309, the control unit 54 determines whether the sub-sensor unit 32b of the fixed-point sensor 32 has detected the sub-magnet. When the sub magnet is detected, the control unit 54 determines whether the polarity of the sub magnet is the S pole (step S311). If it is the S pole, the fixed fixed point information is set to S (step S313), while if it is the N pole, the fixed fixed point information is set to N (step S315), and the process proceeds to step S317. Even when the sub magnet is not detected in step S309, the process proceeds to step S317.

In step S317, the control unit 54 determines whether or not it is a low sensitivity switching fixed point. Here, if the fixed fixed point information=S, the current fixed point information=S, the third fixed point information=N, the second fixed point information=N, and the first fixed point information=N, the low sensitivity switching fixed point is determined, and the release distance= The low-sensitivity switching instruction is given as 200 m. If it is the low sensitivity switching fixed point, the control unit 54 turns on the low sensitivity switching flag (step S319), turns on the slow speed 3.6 km/h instruction flag (step S321), and clears the release distance (step S323). , And proceeds to step S325. In step S317, if it is not the low sensitivity switching fixed point, the process proceeds to step S325.

In step S325, the control unit 54 determines whether the low sensitivity switching flag is on. If the low sensitivity switching flag is on, the release distance is set to 200 m (step S327), and the process proceeds to step S329. On the other hand, if the low sensitivity switching flag is not on in step S325, the process proceeds to step S329. In step S329, the control unit 54 determines whether the traveling distance is equal to or greater than the release distance. If the traveling distance is equal to or longer than the release distance, the control unit 54 turns off the low sensitivity switching flag (step S331), turns off the slow speed 3.6 km/h instruction flag (step S333), and proceeds to step S335. In step S329, if the traveling distance is not the release distance or more, the process proceeds to step S335.

In step S335, the control unit 54 determines whether or not the slow drive 3.6 km/h instruction flag is on. If the slow-moving 3.6 km/h instruction flag is on, the control unit 54 sets the target speed to 3.6 km/h (step S337), the instruction vehicle speed is higher than the target vehicle speed, and the function of the imaging unit 34 is invalid. It is determined whether or not (step S339). If the instructed vehicle speed is higher than the target vehicle speed and the function of the imaging unit 34 is invalid, the instructed vehicle speed is set to the target vehicle speed (step S341), and the process proceeds to step S343. When steps S335 and S339 are NO, it progresses to step S343.

In step S343, the second fixed point information is moved to the first fixed point information, in step S345, the third fixed point information is moved to the second fixed point information, and in step S347, the current fixed point information is moved to the third fixed point information, and the processing is ended.

Next, the reception sensitivity setting processing operation of the rear-end collision prevention sensor 44 will be described with reference to FIGS. 23 and 24.

First, the control unit 54 determines whether or not the function of the imaging unit 34 is valid (step S401). When the CAN communication between the curvature information calculation device 36 and the control unit 54 is established, the function of the imaging unit 34 becomes effective. If the function of the imaging unit 34 is valid, the control unit 54 determines whether the low sensitivity switching flag is on (step S403). If the low-sensitivity switching flag is ON, the control unit 54 determines whether the instructed vehicle speed is 3.6 km/h or less, or the current curvature information is 4 or more (curvature radius is greater than 10 m) ( Step S405). If the instructed vehicle speed is 3.6 km/h or less or the current curvature information is 4 or more, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to low sensitivity (step S407). On the other hand, when the instructed vehicle speed is higher than 3.6 km/h and the current curvature information is less than 4, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to medium sensitivity (step S409).

If the low-sensitivity switching flag is not turned on in step S403, the control unit 54 determines whether the instructed vehicle speed is 3.6 km/h or less (step S411). If the instructed vehicle speed is 3.6 km/h or less, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to low sensitivity (step S413), while if the instructed vehicle speed is not less than 3.6 km/h. The control unit 54 determines whether the current curvature information is 2 or more (the curvature radius is larger than 6 m) (step S415). If the current curvature information is 2 or more, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to medium sensitivity (step S417). On the other hand, if the current curvature information is less than 2, the control unit 54 The reception sensitivity of the rear-end collision prevention sensor 44 is set to low sensitivity (step S419).

If the function of the imaging unit 34 is invalid in step S401, the control unit 54 determines whether the instructed vehicle speed is 8 km/h or less (step S421). If the instructed vehicle speed is 8 km/h or less, the control unit 54 determines whether the instructed vehicle speed is 3.6 km/h or less (step S423). If the instructed vehicle speed is 3.6 km/h or less, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to low sensitivity (step S425), while the instructed vehicle speed is higher than 3.6 km/h and 8 km. If /h or less, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to the medium sensitivity (step S427). If the instructed vehicle speed is higher than 8 km/h in step S421, the control unit 54 sets the reception sensitivity of the rear-end collision prevention sensor 44 to high sensitivity (step S429).

According to such an operation, the detection range of the image pickup unit 34 can be made larger than the detection range of the rear-end collision prevention sensor 44 in a route with good visibility such as a curve with a small bend or a straight road, and the image pickup unit 34 has a predetermined route. It is easy to detect the vehicle in front of P. On the other hand, for example, in the case of a curve with a bad turn and a large curve, the front vehicle on the predetermined route P may not be within the effective field of view of the imaging unit 34, and the rear-end collision prevention sensor 44 may be easier to detect the front vehicle. Therefore, when the curvature information indicates that the degree of bend is small, the image pickup unit 34 mainly performs the function of detecting the preceding vehicle by increasing the detection range of the image pickup unit 34, while the curvature information indicates the degree of bend. When it indicates that the rear-end collision prevention sensor 44 has a large sensitivity, the rear-end collision prevention sensor 44 mainly has a function of detecting the preceding vehicle by appropriately setting the sensitivity of the rear-end collision prevention sensor 44. As a result, the preceding vehicle can be satisfactorily detected regardless of the curvature information, and a good rear-end collision prevention function can be obtained.

Further, by setting the sensitivity of the rear-end collision prevention sensor 44 based on the instruction vehicle speed to the automatic traveling vehicle 10, the sensitivity of the rear-end collision prevention sensor 44, that is, the detection range can be adjusted according to the instruction speed.

Further, by setting the sensitivity of the rear-end collision prevention sensor 44 based on the sensitivity switching instruction, the sensitivity of the rear-end collision prevention sensor 44, that is, the detection range can be adjusted according to the situation of the predetermined route P and its surrounding environment.

When the fixed point sensor 32 receives the sensitivity switching instruction transmitted from the fixed point member 60 provided on the predetermined path P, the sensitivity switching instruction can be easily and surely received.

In the example shown in FIG. 25, in a route with a large effective field of view (curvature radius is more than 24 m), the instruction vehicle speed is as high as 14 km/h, the detection range of the imaging unit 34 is 10.0 m, and the rear-end collision prevention sensor 44 is If there is a low sensitivity switching instruction, the sensitivity will be low. On the other hand, in a curve with a small effective field of view (curvature radius is more than 6 m and 8 m or less), the indicated vehicle speed is as low as 6 km/h, and the detection range of the image pickup unit 34 is 4.0 m (detectable range is 3.7 m). The rear-end collision prevention sensor 44 has medium sensitivity.

In this way, by utilizing the function of the image pickup unit 34 capable of detecting a distant vehicle and changing the sensitivity of the rear-end collision prevention sensor 44 based on the curvature information (curvature radius), the rear-end collision prevention function is improved and the traveling speed is increased. Can be compatible with both.

The distance information is not limited to the travel distance of the autonomous vehicle 10 from the starting point C0, and may be information about the rotation angle of the right front wheel 14 of the autonomous vehicle 10 from the starting point C0.

Further, the fixed point member 60 provided on the predetermined path P is not limited to a magnet and may be an RFID (Radio Frequency IDentification) tag.

The self-driving vehicle according to the present invention can be suitably used for a golf cart, but is not limited to this, and can be used for unmanned work vehicles used in factories, orchards, etc. along the route (runway) in the ground. It is suitable for use in any unmanned vehicle that automatically runs on a buried guide line. Further, the autonomous vehicle according to the present invention is not limited to a four-wheeled vehicle, but may be a three-wheeled vehicle.

10 Autonomous vehicle 30 Guidance sensor 32 Fixed point sensor 34 Imaging unit 36 Curvature information calculation device 36a, 54 Control unit 36b, 56 Storage unit 38 Rotation angle sensor 40 Reception antenna 42 Transmission antenna 44 Rear-end collision prevention sensor 46 Steering unit 48 Drive unit 50 Brake Unit 60 Fixed point member A Runnable distance B Stop distance C0 Starting point d Set distance L Guide line P Default route R Curvature radius before instantaneous interruption R'Average radius of curvature in the 0-2m section

Claims (16)

An autonomous vehicle configured to be able to automatically travel on a predetermined route,
A storage unit that stores position information of a plurality of measurement points from a start point in the predetermined route, and distance information regarding a distance from the start point at each measurement point associated with the position information of each measurement point,
A travel distance acquisition unit that acquires travel distance information regarding the travel distance from the starting point to the current point,
A position detection unit that detects the position information of the current position by collating the distance information acquired by the distance acquisition unit and the distance information read from the storage unit,
A measurement point group consisting of the three measurement points is extracted from the plurality of measurement points at a first predetermined interval, and based on the position information of the three measurement points included in the extracted measurement point group. , Curvature information calculation for calculating curvature information about a radius of curvature of an arc passing through the three measurement points, and calculating the curvature information for a traveling area ahead of the current point based on the position information ahead of the current point Department,
Based on the curvature information calculated for the traveling area ahead of the current location, a vehicle speed control unit for controlling the vehicle speed for the traveling area beyond the current location,
The vehicle speed control unit,
A first determination unit that determines a first range in front of the autonomous vehicle based on an instruction vehicle speed to the autonomous vehicle;
A second determining unit that determines a first target vehicle speed based on a minimum value of the curvature information within the first range;
And a selector for selecting smaller one of the instruction speed and the first target vehicle speed as the instruction speed, automatic traveling vehicle. The vehicle speed control unit further includes a third determination unit that determines a second target vehicle speed based on a minimum value of the curvature information in a second range ahead of the first range,
The automatic vehicle according to claim 1 , wherein the selection unit selects a minimum value among the instruction vehicle speed, the first target vehicle speed, and the second target vehicle speed as the instruction vehicle speed. The second determination unit weights a minimum value of the curvature information within the first range with a current value and a previous value, and determines the first target vehicle speed based on the weighted minimum value,
The third determination unit weights a minimum value of the curvature information in the second range with a current value and a previous value, and determines the second target vehicle speed based on the weighted minimum value. automatic traveling vehicle according to 2. An autonomous vehicle configured to be able to automatically travel on a predetermined route,
A storage unit that stores position information of a plurality of measurement points from a start point in the predetermined route, and distance information regarding a distance from the start point at each measurement point associated with the position information of each measurement point,
A travel distance acquisition unit that acquires travel distance information regarding the travel distance from the starting point to the current point,
A position detection unit that detects the position information of the current position by collating the distance information acquired by the distance acquisition unit and the distance information read from the storage unit,
A measurement point group consisting of the three measurement points is extracted from the plurality of measurement points at a first predetermined interval, and based on the position information of the three measurement points included in the extracted measurement point group. , Curvature information calculation for calculating curvature information about a radius of curvature of an arc passing through the three measurement points, and calculating the curvature information for a traveling area ahead of the current point based on the position information ahead of the current point Department,
A magnetic field detection unit for detecting a magnetic field from the guide wire provided in the predetermined path,
A vehicle speed detector for detecting the vehicle speed,
A time calculation unit that calculates a travel duration based on the curvature information and the current vehicle speed detected by the vehicle speed detection unit,
When the magnetic field from the guide wire detected by the magnetic field detection unit is less than a threshold value, a determination unit that determines whether or not to continue traveling of the autonomous vehicle based on whether or not the traveling duration time has elapsed. provided with a door, automatic running vehicle. The time calculation unit,
A first calculation unit that calculates a travelable distance until the magnetic field detection unit deviates from a detectable range of the magnetic field from the guide line based on the front and rear curvature information;
A second calculation unit that calculates a stop distance that is a distance required to stop based on the current vehicle speed;
A third calculation unit that calculates a travel continued distance based on the travelable distance and the stop distance;
The automatic traveling vehicle according to claim 4 , further comprising: a fourth calculator that calculates the traveling duration based on the traveling duration and the current vehicle speed. The autonomous vehicle according to claim 5 , wherein the traveling duration has an upper limit value. An autonomous vehicle configured to be able to automatically travel on a predetermined route,
A storage unit that stores position information of a plurality of measurement points from a start point in the predetermined route, and distance information regarding a distance from the start point at each of the measurement points associated with the position information of each of the measurement points,
A travel distance acquisition unit that acquires travel distance information regarding the travel distance from the starting point to the current point,
A position detection unit that detects the position information of the current position by collating the travel distance information acquired by the travel distance acquisition unit and the distance information read from the storage unit,
A measurement point group consisting of the three measurement points is extracted from the plurality of measurement points at a first predetermined interval, and based on the position information of the three measurement points included in the extracted measurement point group. , Curvature information calculation for calculating curvature information about a radius of curvature of an arc passing through the three measurement points, and calculating the curvature information for a traveling area ahead of the current point based on the position information ahead of the current point Section and
The position information and the distance information are obtained by traveling the predetermined route in advance,
The autonomous vehicle is further
At each of the measurement points while traveling on the predetermined route, an imaging unit that captures a predetermined direction when viewed from the automatic traveling vehicle,
A position acquisition unit that obtains the position information of each of the measurement points by a method of visual odometry based on a plurality of image data captured by the image capturing unit;
A radio-type detection unit that detects the presence of the other vehicle by receiving radio waves from the other vehicle,
A range setting unit for setting the detection range of the image pickup unit,
And a sensitivity setting unit that sets the sensitivity of the detector on the basis of the curvature information, automatic traveling vehicle. The automated vehicle according to claim 7, wherein the sensitivity setting unit further sets the sensitivity of the detection unit based on an instruction vehicle speed to the automated vehicle. The automated vehicle according to claim 7 , wherein the sensitivity setting unit further sets the sensitivity of the detection unit based on a sensitivity switching instruction. The automatic traveling vehicle according to claim 9 , further comprising a reception unit that receives the sensitivity switching instruction transmitted by a transmission member provided on the predetermined route. The autonomous vehicle according to claim 1 or 4 , wherein the position information and the distance information are obtained by traveling on the predetermined route in advance. At each of the measurement points while traveling on the predetermined route, an imaging unit that captures a predetermined direction when viewed from the automatic traveling vehicle,
The automatic traveling vehicle according to claim 11 , further comprising: a position acquisition unit that obtains the position information of each of the measurement points by a visual odometry method based on a plurality of image data captured by the image capturing unit. Wheels for moving the autonomous vehicle,
An angle detection unit for detecting the rotation angle of the wheel,
The automatic traveling vehicle according to claim 7, 11 or 12 , further comprising: a distance acquisition unit that obtains the distance information of each of the measurement points based on a detection result of the angle detection unit. The curvature information calculating unit, the plurality of extracting a plurality of the measurement point group different from measurement point to calculate the curvature information for each of a plurality of measurement point cloud which is the extraction, according to claim 1, 4 Or the curvature information calculation device described in 7 . The curvature information calculation unit calculates the curvature information of the predefined path separated by a second predetermined distance from the origin, on average the radius of curvature about the measurement points belonging to the same section the same section, claim 14 The curvature information calculation device described in. The automated vehicle according to any one of claims 1 to 15 , which is a golf cart.

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