JP6648629B2 - Autonomous vehicles - Google Patents

Description

  The present invention relates to an autonomous vehicle that travels along a traveling route set along a guide line provided in advance.

  2. Description of the Related Art In recent years, autonomous vehicles that transport parts, products, and the like unattended are used in manufacturing plants for various products. The autonomous vehicle automatically moves along a pre-programmed traveling route along a guide line such as a magnetic tape pasted on a floor surface. The autonomous traveling vehicle automatically performs operations such as acquiring a load at a programmed position, moving (transporting) the cargo along a traveling route, and unloading the cargo at a programmed destination position. In such a manufacturing plant, a plurality of guidance lines are stretched so as to be parallel or intersecting, and one or more autonomous vehicles travel along a unique traveling route according to a program of a control device mounted therein. Move along the guide line. At the intersection where the guide lines intersect, the vehicle travels while turning (changing course) left and right or the like according to a program of a control device mounted on the vehicle.

  For example, in the guidance system for a mobile vehicle described in Patent Literature 1, the vehicle body (corresponding to an autonomous vehicle) is turned at the intersection of the guide lines so that the rear part of the vehicle bulges in a direction opposite to the turning direction, thereby quickly. At this point, a proper posture is taken along the guidance line of the turn. At the time of a turn, the steering angle of the steered wheels is controlled so as to have a steering angle programmed in advance.

JP-A-9-282032

  When the autonomous vehicle turns left and right at the intersection of the guide lines, the vehicle turns the steered wheels at a preset (programmed) steering angle according to the turn angle. For example, at the time of a left 90 ° turn, the control device acquires a preset control amount for the left 90 ° steering, and detects the actual steering angle of the steered wheels using the steering angle detecting means. A steering motor is controlled to control the steered wheels via a steering gear or the like (or the steered wheels are controlled by a preset control amount without using the steering angle detecting means). However, due to mechanical rattling of the steering gear and the steering angle detecting means and aging of the characteristics (aging deterioration), or changes in the load of the motor due to changes in the weight of the load, etc., in the early days (or in the state without the load). In some cases, the trajectory of the turn may deviate from the trajectory of the turn after a long period of time (or when a heavy load is loaded). In such a case, the attitude of the autonomous vehicle at the end of the turn is inclined with respect to the guide line at the turn destination, and the vehicle can meander or go out of course (deviation from the guide line) during the run after the turn. There is. If meandering or course out occurs after the turn, it is necessary to readjust the steering angle (control amount) for each autonomous vehicle, which is very time-consuming.

  The invention described in Patent Literature 1 controls the steering angle of the steered wheels so that the steering angle becomes a pre-programmed steering angle when turning left and right of a moving vehicle (autonomous vehicle). There is no description or suggestion of any measures against mechanical rattling or secular change (aging deterioration) at the time of use or the presence or absence of heavy objects. In this case, if a relatively long time has passed (or a heavy load is loaded), the deviation of the turn trajectory increases, and there is a possibility that the track will meander or go out of course after the end of the turn. It may be necessary to periodically re-adjust for each autonomous vehicle to avoid.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and the mechanical rattling of members and the secular change of characteristics that affect the occurrence of an error in the steering angle during the left and right turns of an autonomous vehicle ( It is an object of the present invention to provide an autonomous vehicle that can automatically correct a steering angle error with respect to aging, etc., and can eliminate the need for readjustment of a steering control amount.

  In order to solve the above problems, the autonomous vehicle according to the present invention employs the following means. First, a first aspect of the present invention is an autonomous vehicle that moves along a traveling route set along a guide line provided in advance, and is disposed in front of the autonomous vehicle to detect the guide line. Front guidance line detecting means to be provided, rear guidance line detecting means arranged behind the autonomous vehicle to detect the guidance line, and a direction of the autonomous vehicle fixed in the front-rear direction of the autonomous vehicle. A driven wheel, which is rotatably provided in a pair of left and right front or rear sides, and a steering unit capable of changing an angle of the autonomous vehicle with respect to the front-rear direction, and is a driven steering wheel driven by the driving unit; Is provided rearward, and when the driven wheel is provided rearward, the drive steering wheel provided, the detection signal from the front guide line detecting means and the rear side Guide wire detection A control device that controls the driving unit and the steering unit based on the detection signal and the traveling route from to move the autonomous traveling vehicle along the traveling route along the guide line, The travel route has an intersection where the plurality of guide lines intersect. And when the control device turns at an intersection according to the traveling route, the control device is configured to perform the steering based on a steering angle set in advance corresponding to the intersection of the traveling route and a correction angle for correcting the steering angle. Turn the intersection by controlling the steering means and the driving means, the deviation distance according to the angle between the guidance line of the turn destination and the longitudinal direction of the autonomous vehicle when it is determined that the intersection has been turned is determined. And an autonomous vehicle that performs correction by steering based on the correction angle at the next intersection.

  Next, a second invention of the present invention is the autonomous vehicle according to the first invention, wherein the type of turn at the intersection according to the travel route includes a plurality of types including the left and right directions of the turn. And the autonomous vehicle has a load detecting means for detecting the presence or absence of a load. The control device stores the steering angle preset in accordance with the type of turn and the presence / absence of the load, and the correction angle corresponding to the type of turn and the presence / absence of the load. When turning at an intersection according to the traveling route, the steering unit and the driving unit are controlled based on the type of turn and the steering angle and the correction angle corresponding to the presence or absence of the cargo, and the intersection is controlled. An autonomous vehicle that changes the correction angle corresponding to the type of turn and the presence or absence of the cargo based on the deviation distance when it is determined that the turn has been completed.

  Next, a third invention of the present invention is the autonomous vehicle according to the second invention, wherein the control device, when turning at an intersection according to the traveling route, determines the type of turn in the current turn. The autonomous vehicle is configured such that an angle smaller than an angle for canceling the shift distance detected in a previous turn in which presence or absence of a load is the same is set as the correction angle used in the current turn.

  According to the first aspect of the present invention, the deviation distance between the autonomous vehicle and the guide line at the turn when it is determined that the intersection has been turned is corrected at the next intersection by steering based on the correction angle. As a result, the steering angle error is automatically corrected in response to the mechanical rattling of the members or the aging (deterioration of characteristics) of the members that affect the occurrence of the steering angle error during the left and right turns of the autonomous vehicle. Can be corrected. Therefore, it is not necessary to readjust the control amount for steering. Also, by detecting the final deviation distance when the intersection has been turned, regardless of which member has an error and how much error has occurred, the final error obtained by integrating the errors of each member is turned. It can be corrected every time.

  According to the second aspect, the steering angle and the correction angle are stored in association with the type of turn and the presence or absence of a load. This makes it possible to make corrections according to the respective situations, depending on the type of turn of the autonomous vehicle and the presence or absence of a load (the magnitude of the load on the motor).

  According to the third aspect of the invention, the deviation distance generated at the time of the turn is not corrected at once in the next turn, but is corrected gradually in each turn, so that the error is reduced in each turn. Thereby, it can be expected that erroneous learning is prevented and unexpected problems are avoided.

1 is a perspective view illustrating an example of the appearance of an autonomous vehicle according to the present invention. FIG. 2 is a schematic plan view of the autonomous traveling vehicle shown in FIG. 1, illustrating an arrangement of wheels of the autonomous traveling vehicle and an arrangement of various detection units and actuators connected to a control device that controls traveling. is there. It is an example of the top view of the manufacturing factory etc. in which the guidance line was set up, and is a figure explaining the example in which the autonomous vehicle travels according to the travel route while traveling straight or turning left and right along the guidance line. It is a flowchart explaining the example of a processing procedure of the control apparatus of an autonomous vehicle in the first embodiment (spin turn). FIG. 9 is a diagram illustrating an example of an operation in which the autonomous traveling vehicle makes a 90 ° left turn at an intersection of a guide line in the first embodiment, and illustrates an example of a straight-ahead operation state before the autonomous traveling vehicle reaches the intersection. In the first embodiment, this is an example of an operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and the autonomous vehicle reaches the turn position and stops after the state shown in FIG. It is a figure showing the example of. In the first embodiment, this is an example of an operation in which the autonomous traveling vehicle makes a 90-degree left turn at the intersection of the guide lines. After the state shown in FIG. It is a figure showing the example of the state where the angle was made into the angle for a 90-degree left turn. In the first embodiment, this is an example of the operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and after the state shown in FIG. 7, the autonomous vehicle maintains the steering angle of the drive steered wheels. FIG. 7 is a diagram illustrating an example of a state in which a drive steering wheel is driven in a state of being turned and a left 90 ° turn is completed in an “ideal state”. In the first embodiment, this is an example of the operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and after the state shown in FIG. 7, the autonomous vehicle maintains the steering angle of the drive steered wheels. FIG. 9 is a diagram showing an example of a state in which the drive steering wheel is driven in the state of being turned and the “actually” 90 ° left turn has been completed. FIG. 6 is a diagram illustrating an example of a correction angle and a basic steering angle stored in association with a type of turn and presence / absence of cargo in the first embodiment. It is a flow chart explaining an example of a processing procedure of a control device of an autonomous vehicle in a 2nd embodiment (pivot turn). In the second embodiment, it is an example of an operation in which an autonomous vehicle makes a 90 ° left turn at an intersection of a guide line, and is a diagram illustrating an example of a straight-ahead operation state before the autonomous vehicle reaches the intersection. In the second embodiment, this is an example of an operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and the autonomous vehicle reaches the turn position and stops after the state shown in FIG. It is a figure showing the example of. In the second embodiment, this is an example of an operation in which the autonomous traveling vehicle makes a 90-degree left turn at the intersection of the guidance lines. After the state shown in FIG. It is a figure showing the example of the state where the angle was made into the angle for a 90-degree left turn. In the second embodiment, this is an example of an operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and after the state shown in FIG. 14, the autonomous vehicle maintains the steering angle of the drive steered wheels. FIG. 7 is a diagram illustrating an example of a state in which a drive steering wheel is driven in a state of being turned and a left 90 ° turn is completed in an “ideal state”. In the second embodiment, this is an example of an operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and after the state shown in FIG. 14, the autonomous vehicle maintains the steering angle of the drive steered wheels. FIG. 9 is a diagram showing an example of a state in which the drive steering wheel is driven in the state of being turned and the “actually” 90 ° left turn has been completed. FIG. 15 is a diagram illustrating an example of a correction angle and a basic steering angle stored in association with a type of turn and presence / absence of cargo in the second embodiment. It is a flow chart explaining an example of a processing procedure of a control device of an autonomous vehicle in a 3rd embodiment (program steer). In the third embodiment, it is an example of an operation in which an autonomous vehicle makes a 90 ° left turn at an intersection of a guide line, and is a diagram illustrating an example of a straight-ahead operation state before the autonomous vehicle reaches the intersection. In the third embodiment, this is an example of an operation in which the autonomous vehicle makes a 90 ° left turn at the intersection of the guide lines, and after the state shown in FIG. FIG. 8 is a diagram illustrating an example in which a steering (program steering) is performed and a left turn is made by 90 °. In the third embodiment, this is an example of an operation in which an autonomous vehicle makes a 90 ° left turn at an intersection of a guide line, and after the state shown in FIG. It is a figure showing the example of the state where it fell. FIG. 14 is a diagram illustrating an example of a corrected addition angle and a basic addition angle stored in association with a type of turn and presence / absence of cargo in the third embodiment.

  An embodiment for carrying out the present invention will be described below with reference to the drawings. In the drawings in which the X axis, the Y axis, and the Z axis are described, the X axis, the Y axis, and the Z axis are orthogonal to each other. The Z-axis direction indicates a vertically upward direction, the X-axis direction indicates one direction (rightward on the paper in the example of FIG. 2) in the factory (inside the facility) shown in FIG. 2, and the Y-axis direction indicates FIG. It shows a direction (upward on the paper in the example of FIG. 2) orthogonal to one direction in the factory (in the facility).

● [Appearance of autonomous vehicle (Fig. 1)]
The autonomous traveling vehicle 1 has various appearances according to applications and work sites. In the description of the present embodiment, an autonomous traveling vehicle having the appearance of a reach-type forklift as shown in FIG. It will be described as. The autonomous vehicle 1 has a reach 10, a mast 70, a fork 60, a right driven wheel 8R, a left driven wheel 8L, a drive steering wheel 8D, a caster wheel 8C, and the like.

  The reach 10 is provided as a pair of left and right, and is provided so as to protrude forward from a lower portion of the vehicle body. A right driven wheel 8R and a left driven wheel 8L are provided on the front side of each of the pair of reach 10s. The mast 70 is provided as a pair of left and right sides, is slidable in the front-rear direction along the reach 10, and is tiltable in the front-rear direction. The forks 60 are provided as a left and right pair, and are slidable vertically (movable up and down) along the mast 70.

  The right driven wheel 8R is provided in the vicinity of the front end of the right reach 10, is fixed in the front-rear direction of the autonomous vehicle 1 (X-axis direction in the example of FIGS. 1 and 2), and is rotatably provided. ing. The left driven wheel 8 </ b> L is provided near the front end of the left reach 10, is fixed in the front-rear direction (the X-axis direction in the examples of FIGS. 1 and 2) of the autonomous vehicle 1, and is rotatably provided. ing. The right driven wheel 8R and the left driven wheel 8L are provided on the autonomous vehicle 1 as a pair of left and right wheels. Note that the right driven wheel 8R and the left driven wheel 8L may be provided in a pair of left and right in front of the autonomous vehicle 1, or may be provided in a pair of left and right behind the autonomous vehicle 1. In the description of the present embodiment, an example in which right driven wheel 8R and left driven wheel 8L are provided as a pair of left and right wheels in front of autonomous traveling vehicle 1 will be described.

  The drive steering wheel 8D has a steering motor 52 (corresponding to a steering means, see FIG. 2) capable of changing an angle of the autonomous vehicle 1 with respect to the front-rear direction (an angle with respect to the center axis 1J in FIG. 2). It is rotationally driven by driving means (see FIG. 2). It should be noted that the number of the drive steered wheels 8D is one, and when the driven wheels (the right driven wheel 8R and the left driven wheel 8L) are provided in the front, the drive steered wheels 8D are provided in the rear and the driven wheels (the right driven wheels 8R). 8R and the left driven wheel 8L) are provided at the rear, the drive steering wheel 8D is provided at the front. The drive steered wheels 8D may be arranged on either the right or left side in the left-right direction. However, when the drive steering wheel 8D is arranged on the right side, the caster wheel 8C (see FIG. 2) is arranged on the left side, and when the drive steering wheel 8D is arranged on the left side, the caster wheel 8C (see FIG. 2). Is located on the right. In the description of the present embodiment, an example in which the drive steering wheel 8D is provided behind and on the left side of the autonomous vehicle 1 will be described.

  The caster wheel 8C is a wheel supported by the autonomous vehicle 1 so as to freely change its direction in the XY plane shown in FIG. 2 and supported by the autonomous vehicle 1 to be rotatable. . In the description of the present embodiment, an example in which caster wheels 8C are provided behind and on the right side of autonomous vehicle 1 will be described.

● [Disposition of various detection means and actuators connected to control device 50 (FIG. 2)]
Next, various detectors and actuators connected to the control device 50 of the autonomous vehicle 1 will be described with reference to FIG. As shown in FIG. 2, the autonomous vehicle 1 includes a control device 50, a front guide line detecting unit 2A, a rear guide line detecting unit 2B, a right marker detecting unit 2R, a left marker detecting unit 2L, a cargo detecting unit 2C, A drive motor 51, a steering motor 52, a pump motor 61, a hydraulic pump 62, and the like are provided. In addition, the autonomous vehicle 1 travels along a guide line (for example, a magnetic tape) provided in advance on a floor or the like, and guides a predetermined traveling route from a plurality of guide lines. Following the line, the vehicle travels while moving forward and backward, and making left and right turns at the intersection of the guidance lines.

  The front guide line detecting means 2A is arranged in front of and below the autonomous vehicle 1, detects a guide line provided on the floor or the like so as to extend in a line, and sends a detection signal to the control device 50. Output. For example, when the guide wire is a magnetic tape, the front guide wire detection means 2A is a magnetic sensor, and the width 2Aw in the left-right direction is, for example, about 20 [cm]. Based on the detection signal from the front guide line detection means 2A, the control device 50 determines how far the guide line existing below the front guide line detection means 2A is to the left or right of the front detection center 2Ac, and how far. Or it can be detected.

  The rear guide line detecting means 2B detects a guide line which is disposed behind and below the autonomous vehicle 1 and is provided to extend linearly on a floor or the like, and sends a detection signal to the control device 50. Output. For example, when the guide wire is a magnetic tape, the rear guide wire detecting means 2B is a magnetic sensor, and the width 2Bw in the left-right direction is, for example, about 20 [cm]. Based on the detection signal from the rear guide line detecting means 2B, the control device 50 determines how much the guide line present below the rear guide line detecting means 2B is located on the left or right of the rear detecting means center 2Bc. It can be detected whether or not they are far apart.

  The right marker detecting means 2R is disposed on the right side and below the rear guiding line detecting means 2B (or the front guiding line detecting means 2A), and is provided with a right marker (an intersection of the guiding lines) provided as a spot on a floor or the like. Is detected, and a detection signal is output to the control device 50. For example, when the right marker is a magnetic tape or a magnet, the right marker detecting means 2R is a magnetic sensor. The control device 50 can detect whether or not there is a right marker below the right marker detecting means 2R based on the detection signal from the right marker detecting means 2R. Note that the distance 2Rw from the center axis 1J to the right marker detecting means 2R is appropriately set according to the position of the right marker.

  The left marker detecting unit 2L is disposed on the left side and below the rear guiding line detecting unit 2B (or the front guiding line detecting unit 2A), and is provided with a left marker (intersection of the guiding lines) provided on the floor surface or the like as a spot. Is detected, and a detection signal is output to the control device 50. For example, when the left marker is a magnetic tape or a magnet, the left marker detecting unit 2L is a magnetic sensor. The control device 50 can detect whether or not there is a left marker below the left marker detection unit 2L based on the detection signal from the left marker detection unit 2L. Note that the distance 2Lw from the center axis 1J to the left marker detecting means 2L is appropriately set according to the position of the left marker.

  The cargo detection unit 2C is, for example, an object detection sensor provided on the upper surface of the fork 60, and outputs a detection signal corresponding to the presence or absence of a cargo on the upper surface of the fork 60 to the control device 50. The control device 50 can detect whether the autonomous vehicle 1 has a load or not, based on the detection signal from the load detection means 2C.

  The drive motor 51 rotates the drive steering wheel 8D via a drive gear or the like to move the autonomous vehicle 1 forward, backward, stop, and the like. The control device 50 can output a control signal to the drive motor 51 to control the drive steering wheel 8D to a state such as forward rotation, reverse rotation, and stop. The control device 50 can detect the rotation state of the drive motor 51 based on a detection signal from rotation detection means such as an encoder (not shown), and can detect the traveling distance of the autonomous traveling vehicle 1.

  The steering motor 52 changes the steering angle of the drive steering wheel 8D via a steering gear or the like, and changes the traveling direction of the autonomous traveling vehicle 1 to the left or right. The control device 50 can output a control signal to the steering motor 52 to control the steering angle of the drive steering wheel 8D (the angle with respect to the center axis 1J of the autonomous traveling vehicle 1). Further, the control device 50 can detect the rotation state of the steering motor 52 based on a detection signal from rotation detection means such as an encoder (not shown), and can detect the steering angle of the drive steering wheel 8D.

  The pump motor 61 is an electric motor for driving the hydraulic pump 62. The control device 50 outputs a control signal to the pump motor 61 and drives the hydraulic pump 62 through the pump motor 61 to generate hydraulic pressure for performing operations such as sliding and tilting of the mast, and lifting and lowering of the fork. Can be done.

  The center of a virtual straight line 8Pv connecting the right driven wheel center 8Rc, which is the center of the right driven wheel 8R, and 8Lc, which is the center of the left driven wheel 8L, is defined as the center 8Pc of the left and right driven wheels.

● [Example of guide line and example of travel route (Fig. 3)]
FIG. 3 shows an example of a plan view of a manufacturing factory or the like in which a guide wire is stretched on the floor surface. The floor is provided with guide lines X1 and X2 in the left-right direction (X-axis direction) in FIG. 3 and the guide lines Y1 and Y2 in the up-down direction (Y-axis direction) in FIG. In FIG. 3, the position where the guidance line X1 and the guidance line Y1 intersect is the intersection X1Y1, the position where the guidance line X1 and the guidance line Y2 intersect is the intersection X1Y2, and the position where the guidance line X2 and the guidance line Y1 intersect. The intersection X2Y1 and the position where the guidance line X2 and the guidance line Y2 intersect are indicated by the intersection X2Y2.

The traveling route K1 is programmed in advance in the control device of the autonomous traveling vehicle 1. In the example of the traveling route K1 indicated by a dotted line in FIG. 3, the autonomous traveling vehicle 1 travels as follows, for example.
(1) Start while holding the cargo a from the left end of the guide line X2, and move rightward along the guide line X2 based on the programmed traveling route.
(2) The left marker ML1 is detected, and the vehicle turns 90 ° left at the next intersection X2Y1 based on the programmed traveling route, and moves upward in FIG. 3 along the guide line Y1.
(3) The stop marker MS1 is detected, and based on the programmed travel route, the vehicle stops before the facility SE1, and the held load a is dropped to the machining entrance receiving unit.
(4) The vehicle makes a 180 ° turn based on the programmed travel route and moves downward in FIG. 3 along the guide line Y1.
(5) The left marker ML2 is detected, and the vehicle turns 90 ° left at the next intersection X1Y1 based on the programmed traveling route, and moves rightward in FIG. 3 along the guidance line X1.
(6) The left marker ML3 is detected, and the vehicle turns 90 ° left at the next intersection X1Y2 based on the programmed traveling route, and moves upward in FIG. 3 along the guide line Y2.
(7) The stop marker MS2 is detected, and based on the programmed travel route, the vehicle stops before the facility SE1 and holds the cargo b of the processing end payout section.
(8) Based on the programmed travel route, the vehicle turns 180 ° and moves downward in FIG. 3 along the guide line Y2.
(9) The left marker ML4 is detected, and the vehicle turns 90 ° left at the next intersection X1Y2 based on the programmed traveling route, and moves rightward in FIG. 3 along the guidance line X1.

  Mechanical rattling of the steering motor, the steering gear, and the steering angle detection means (for example, the encoder of the steering motor) and aging of the characteristics (aging deterioration), or changes in the load of the motor due to the presence or absence of a load (the presence or absence of a heavy object), etc. At, errors may occur in turns. As the errors accumulate, the attitude of the autonomous vehicle after the end of the turn eventually becomes greatly inclined with respect to the guide line at the end of the turn. ). In order to avoid this, it is necessary to periodically readjust the turn control amount and the like for each autonomous vehicle, which is very time-consuming. Accordingly, a control method for an autonomous vehicle that can automatically correct a turn error and eliminate the need for readjustment will be described below.

  There are three types of turns at intersections: a spin turn that turns on the spot, a pivot turn that turns on the spot (the turning center position is different from the spin turn), and a program steer that turns while moving. There is a turn. In addition to the above three types of turns, there are a right turn or a left turn, a 90 ° turn or a 180 ° turn, a turn with a load or a turn without a load.

  Hereinafter, in the first embodiment, a 90 ° left turn (without cargo) in a spin turn will be described as an example, and in the second embodiment, a 90 ° left turn (without cargo) in a pivot turn will be described. In the third embodiment, a description will be given of a 90 ° left turn (with no cargo) in program steering as an example.

● [First Embodiment (Example of 90 ° Left Spin Turn) (FIGS. 4 to 10)]
The flowchart illustrated in FIG. 4 illustrates an example of a processing procedure of a turn process of the control device according to the first embodiment. When the processing is started, the control device proceeds to step S10. Hereinafter, a case where the autonomous traveling vehicle 1 starts moving from the left end of the guide line X2 shown in FIG. 3 will be described as an example. The “spin turn” described in the present embodiment is a turn that turns right or left around the center 8Pc of the left and right driven wheels as a turning center, as shown in FIG. 7, and four wheels (drive steering) during the turn. This is a turn in which all positions of the wheel 8D, the caster wheel 8C, the right driven wheel 8R, and the left driven wheel 8L) move. In the following description, an example of a state in which the autonomous traveling vehicle 1 does not hold a load will be described.

  In step S10, the control device connects the guide line to the center 2Ac (see FIG. 2) of the front detection means of the front guide line detection means 2A and the center 2Bc of the rear detection means (see FIG. 2) of the rear guide line detection means 2B. By controlling the steering motor 52 and the drive motor 51 (see FIG. 2) so that the center axis X2c of X2 is located, the steering angle and drive of the drive steered wheels are controlled, and the autonomous vehicle 1 is moved to the guidance line X2. And the process proceeds to step S15. The state in which the autonomous vehicle 1 is moving along the guidance line X2 is as shown in FIG.

  In step S15, the control device determines whether or not the vehicle has reached the turn position. If it is determined that the vehicle has reached the turn position (Yes), the process proceeds to step S20. If the vehicle has not reached the turn position (No), It returns to step S10. Then, when the process proceeds to step S20, the control device stops driving the drive motor 51 to stop driving the drive steered wheels, stops the autonomous traveling vehicle 1, and proceeds to step S25. In Steps S15 and S20, specifically, as shown in FIG. 6, after detecting the left marker ML1 by the left marker detecting means 2L, the control device moves by the distance D1 along the guide line X2. It is determined that the vehicle has reached the turn position, and the autonomous vehicle 1 is stopped (the distance D1 is appropriately set). The position of the left and right driven wheel center 8Pc in the stopped autonomous vehicle 1 coincides with the center position of the intersection X2Y1. That is, in a state where the center 8Pc of the left and right driven wheels coincides with the center of the intersection X2Y1 (the state shown in FIG. 6), the left marker ML1 is provided at a position left of the left marker detecting means 2L by the distance D1.

  In step S25, the control device determines whether the turn at the current intersection (in this case, the intersection X2Y1) according to the preset (programmed) travel route is a right turn, If it is a right turn (Yes), the process proceeds to step S30. If it is not a right turn (No, left turn), the process proceeds to step S30E. The right turn and the left turn are one of the types of turns.

  When proceeding to step S30, the control device determines whether or not the turn at the current intersection (in this case, the intersection X2Y1) according to the preset traveling route is a 90 ° turn, and If it is a turn (Yes), the process proceeds to step S35A, and if it is not a 90 ° turn (No, 180 ° turn), the process proceeds to step S35C. When the process proceeds to step S30E, the control device determines whether or not the turn at the current intersection (in this case, the intersection X2Y1) according to the preset traveling route is a 90 ° turn, If it is a 90 ° turn (Yes), the process proceeds to step S35E, and if it is not a 90 ° turn (No, 180 ° turn), the process proceeds to step S35G. The 90 ° turn and the 180 ° turn are one of the types of turns.

  When proceeding to step S35A, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detecting means 2C (see FIG. 2). If there is a cargo (Yes), the control device proceeds to step S40A and there is no cargo. In the case (No), the process proceeds to Step S40B. When proceeding to step S35C, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detection means 2C. If there is a cargo (Yes), the control device proceeds to step S40C, and if there is no cargo (No), Proceed to step S40D. When proceeding to step S35E, the control device determines the presence / absence of a cargo based on the detection signal from the cargo detecting means 2C. If there is a cargo (Yes), the control proceeds to step S40E, and if there is no cargo (No), Proceed to step S40F. When proceeding to step S35G, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detecting means 2C. If there is a cargo (Yes), the process proceeds to step S40G, and if there is no cargo (No), Proceed to step S40H.

  When proceeding to step S40A, the control device substitutes (stores) “1” (right, 90 °, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S40B, the control device substitutes (stores) “2” (right, 90 °, no cargo) for the turn type, and proceeds to step S45. When proceeding to step S40C, the control device substitutes (stores) “3” (right, 180 °, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S40D, the control device substitutes (stores) “4” (right, 180 °, no cargo) for the turn type, and proceeds to step S45. When proceeding to step S40E, the control device substitutes (stores) “5” (left, 90 °, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S40F, the control device substitutes (stores) “6” (left, 90 °, no cargo) for the turn type, and proceeds to step S45. When proceeding to step S40G, the control device substitutes (stores) “7” (left, 180 °, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S40H, the control device substitutes (stores) “8” (left, 180 °, no cargo) for the turn type, and proceeds to step S45.

  The control device has storage devices (ROM and RAM), and the ROM of the storage device stores the program of this processing and the basic steering angles 1 to 8 in the spin turn basic steering angles shown in FIG. ing. For example, in the case of [left turn, 90 ° turn, and no cargo] in the spin turn, the basic steering angle 6 is the steering angle θ1 of the drive steering wheel 8D in the state shown in FIG. Steering angle) is stored. The correction angles 1 to 8 in the spin turn correction angles shown in FIG. 10 are stored in the RAM (or FlashROM) of the storage device. The correction angles 1 to 8 can be rewritten. For example, the correction angle 6 includes the steering angle θ1 (before correction) in the state shown in FIG. 7 in the case of [left turn, 90 ° turn, and no cargo] in the spin turn. (A steering angle) is stored. The method of calculating the correction angle will be described later.

  In step S45, the control device reads the basic steering angle (n) and the correction angle (n) corresponding to the turn type (n), calculates a total steering angle (basic steering angle + correction angle), and proceeds to step S50. . When the autonomous vehicle 1 without cargo turns the intersection X2Y1 by 90 ° to the left, since the turn type is “6”, the control device determines that the basic steering angle 6 among the spin turn basic steering angles shown in FIG. And the correction angle 6 in the spin turn correction angle shown in FIG. 10 is read, and the basic steering angle 6 and the correction angle 6 are added to calculate the total steering angle. The correction angle 6 is a correction angle stored at the end of the previous turn of the turn type “6”, as described later.

  In step S50, the control device controls the steering motor 52 to control the steering angle of the drive steered wheels 8D so that the total steering angle obtained in step S45 is obtained while the autonomous vehicle 1 is stopped. Then, the process proceeds to step S55. In step S55, the control device controls the drive motor 51 to drive the drive steering wheel 8D in a left-turn direction while maintaining the steering angle of the drive steering wheel 8D at the total steering angle, and executes a turn. Proceed to S60. In step S60, the control device determines whether or not it is the timing to end the turn. If it is determined that the turn is to be ended (Yes), the process proceeds to step S65. If it is not determined that the turn is to be ended (No), the process returns to step S55. . In step S60, specifically, the control device determines that the distance between the guide line Y1 at the turn destination (the center axis Y1c of the guide line Y1) and the center 2Bc of the rear-side detection means, and which gradually decreases, is obtained. When the distance is within a predetermined distance E1 (an end determination distance, for example, about −10 [mm] to +10 [mm]) (see FIG. 9), it is determined that the turn is ended. For example, when the sign is (-), it indicates that the center 2Bc of the rear detection means is on the left side of the center axis Y1c of the guide line Y1, and when the sign is (+), the center 2Bc of the rear detection means is the guide line Y1. On the right side of the center axis Y1c. Then, in step S65, the control device stops driving the driving motor 51 to stop driving the driving steered wheels 8D, puts the autonomous traveling vehicle 1 in a stopped state, and proceeds to step S70.

  An example of a method of determining the steering angle θ1 (basic steering angle) at the time of the spin turn in the case of “left turn, 90 ° turn, and no cargo” will be described with reference to FIG. As shown in FIG. 7, in the spin turn to the left of 90 °, the center 8Pc of the left and right driven wheels of the autonomous vehicle 1 is made to coincide with the center position of the intersection X2Y1, and the counterclockwise direction is centered on the center 8Pc of the left and right driven wheels. Make a (almost) 90 ° turn. Here, the length of the virtual straight line VL1 from the center 8Pc of the left and right driven wheels to the center 8Dc of the drive steering wheel is defined as a length R1, and the virtual circle having the radius R1 around the center 8Pc of the left and right driven wheels is defined as a virtual circle VC1. The tangent to the virtual circle VC1 at the drive steering wheel center 8Dc is defined as a virtual tangent S1. The angle (the angle in the turn direction) formed by the virtual tangent line S1 and the guide line X2 is the steering angle θ1 (corresponding to the basic steering angle 6 in this case). If various states such as the steering angle of the drive steered wheels 8D are in the ideal state, when the turn is completed, the center 8Pc of the left and right driven wheels is at the intersection X2Y1 as shown in [End of turn in ideal state]. Match with the center. At this time, the center 2Ac of the front detection means and the center 2Bc of the rear detection means are on the center axis Y1c of the guide line Y1 (when the predetermined distance E1 shown in FIG. 9 is set to zero). However, since there are actually various errors including the steering angle, when the turn is completed, the center 8Pc of the left and right driven wheels 8Pc is located at the intersection X2Y1 at the end of the turn as shown in [at the end of actual turn] in FIG. The autonomous vehicle 1 is displaced from the center and is inclined with respect to the guide line Y1 after the turn.

  In step S70, the control device detects a displacement distance (distance E2) corresponding to the displacement angle θe in the state shown in FIG. 9, and proceeds to step S75. Specifically, the control device detects a distance E2 between the center 2Ac of the front detection means and the center axis Y1c of the guide line Y1 at the turn destination, and detects the distance E2 between the center 2Bc of the rear detection means and the center axis Y1c of the guide line Y1 at the turn destination. Is detected. Further, a distance LAB from the center 2Ac of the front detection means to the center 2Bc of the rear detection means is stored in advance in the storage device of the control device. In this case, the deviation angle θe is an angle formed by the guide line (the guide line Y1 in the example of FIG. 9) to which the turn has been made and the front-rear direction of the autonomous vehicle 1 when it is determined that the turn has been completed in step S60. , Sin θe = [(distance E1 + distance E2) / distance LAB]. Since the distance E1 is so small that it can be neglected, the distance E1 may be approximated as sin θe ≒ [distance E2 / distance LAB], or the distance E2 (deviation distance) ≒ distance LAB * sinθe.

  In step S75, the control device converts the offset angle for preventing the shift distance (distance E2) from being generated from the shift distance (distance E2), and corrects the angle based on the converted offset angle (for example, 1/10 of the offset angle). Is obtained, and the process proceeds to step S80. Note that the correction angle converted from the shift distance (distance E2) is, in the example of FIG. 9, the correction angle depending on whether the center 2Ac of the front detection means is on the right side or the left side of the center axis Y1c of the guide line Y1. Have different signs. Then, in step S80, the control device stores the obtained correction angle in the correction angle (n) corresponding to the turn type (n), and returns to step S10. For example, when the turn type is “6”, the obtained correction angle is stored in the correction angle 6, and the value of the correction angle 6 is used in the next turn type “6”.

  As described above, in the first embodiment, when the turn is a spin turn, an error occurs in the steering angle, and a shift distance (distance E2) corresponding to the shift angle θe occurs in the attitude of the autonomous vehicle after the turn. At this time, a learning angle is calculated so as to cancel the misalignment distance (distance E2) (so that the misalignment distance does not occur) and to use the obtained amendment angle in the next turn. As a result, a turn error can be automatically corrected. In addition, by setting an angle smaller than the offset angle at which the offset distance (distance E2) is canceled at one time as the correction angle, the offset distance (distance E2) is not canceled at one time at the next turn, but a plurality of times. The deviation distance is gradually reduced with each turn, and erroneous learning can be prevented. In addition, by having the basic steering angles 1 to 8 and the correction angles 1 to 8 corresponding to the types of turns of left turn or right turn, 90 ° turn or 180 ° turn, with or without cargo, to the drive steering wheel. The turn error can be automatically corrected more accurately in accordance with the load condition and the like.

● [Second embodiment (example of left 90 ° pivot turn) (FIGS. 11 to 17)]
In the second embodiment, the turn at the intersection is a pivot turn, in contrast to the first embodiment in which the turn at the intersection is a spin turn. In the spin turn of the first embodiment, all positions of the four wheels (all wheels) move during the turn (while turning), but in the pivot turn of the second embodiment, during the turn (while turning) ), Turn right or left around one of the wheels. In the case of a pivot turn, for example, a left turn turns left (counterclockwise) about the left driven wheel center 8Lc, and a right turn turns right (clockwise) about the right driven wheel center 8Rc. , Is different from the first embodiment. Further, in the processing procedure, as shown in the flowchart of FIG. 11, step S15 of FIG. 4 is changed to step S16 in FIG. 11, and the processing of steps S25 to S45 is performed as shown in the flowchart of FIG. Are different. As shown in FIG. 17, the basic steering angle and the correction angle are stored as angles dedicated to the pivot turn. Also, the pivot turn assumes a 90 ° turn, but does not assume a 180 ° turn (a 180 ° turn would greatly deviate from the guidance line), so the basic steering angle and the correction angle are each four. Also differs from the first embodiment. Hereinafter, these differences will be mainly described. In the following description, an example of a state in which the autonomous traveling vehicle 1 does not hold a load will be described.

  As shown in the flowchart of FIG. 11, when the processing is started, the control device proceeds to step S10. Hereinafter, processing different from the flowchart of FIG. 4 will be mainly described.

  In step S16, the control device determines whether or not the vehicle has reached the turn position. If it is determined that the vehicle has reached the turn position (Yes), the process proceeds to step S20. If the vehicle has not reached the turn position (No), It returns to step S10. Then, when the process proceeds to step S20, the control device stops driving the drive motor 51 to stop driving the drive steered wheels, stops the autonomous traveling vehicle 1, and proceeds to step S25. In Steps S16 and S20, specifically, as shown in FIG. 13, the control device moves forward from the state shown in FIG. 12, detects the left marker ML1 by the left marker detecting means 2L, and then guides by the distance D2. It is determined that the vehicle has reached the turn position at the position moved along the line X2, and the autonomous vehicle 1 is stopped (the distance D2 is appropriately set). The position of the left driven wheel center 8Lc (or the right driven wheel center 8Rc) in the stopped autonomous vehicle 1 is located at a distance D2A from the center axis Y1c of the guide line Y1, and "distance D2A = (right driven wheel center 8Rc)". And the distance D2 between the left marker ML1 and the left driven wheel center 8Lc) / 2.

  In step S25, the control device determines whether the turn at the current intersection (in this case, the intersection X2Y1) according to the preset (programmed) travel route is a right turn, If it is a right turn (Yes), the process proceeds to step S35A, and if it is not a right turn (No, left turn), the process proceeds to step S35E. The right turn and the left turn are one of the types of turns.

  When proceeding to step S35A, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detecting means 2C (see FIG. 2). If there is a cargo (Yes), the control device proceeds to step S40A and there is no cargo. In the case (No), the process proceeds to Step S40B. When proceeding to step S35E, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detection means 2C. If there is a cargo (Yes), the process proceeds to step S41E, and if there is no cargo (No), Proceed to step S41F.

  When proceeding to step S40A, the control device substitutes (stores) “1” (right 90 °, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S40B, the control device substitutes (stores) “2” (90 ° right, no cargo) for the turn type, and proceeds to step S45. When proceeding to step S41E, the control device substitutes (stores) “3” (90 ° left, with cargo) for the turn type, and proceeds to step S45. When proceeding to step S41F, the control device substitutes (stores) “4” (90 ° left, no cargo) for the turn type, and proceeds to step S45.

  The control device has a storage device (ROM and RAM), and the ROM of the storage device stores a program of this process and basic steering angles 1 to 4 in the pivot turn basic steering angle shown in FIG. . For example, the basic steering angle 4 includes the steering angle θ2 of the drive steering wheel 8D in the state shown in FIG. 14 (the steering angle in the ideal state where no correction is required) in the case of [90 ° left turn and no cargo] in the pivot turn. Is stored. The correction angles 1 to 4 in the pivot turn correction angle shown in FIG. 17 are stored in the RAM (or FlashROM) of the storage device. The correction angles 1 to 4 can be rewritten. For example, the correction angle 4 is the steering angle θ2 (the steering angle before correction) in the state shown in FIG. 14 in the case of [90 ° turn left and no cargo] in the pivot turn. ) Is stored. The method of calculating the correction angle will be described later.

  In step S45, the control device reads the basic steering angle (n) and the correction angle (n) according to the turn type (n), calculates the total steering angle (basic steering angle + correction angle), and proceeds to step S50. This is the same as the first embodiment. When the autonomous vehicle 1 without cargo turns the intersection X2Y1 by 90 ° to the left, since the turn type is “4”, the control device determines that the basic steering angle 4 among the pivot turn basic steering angles shown in FIG. And the correction angle 4 among the pivot turn correction angles shown in FIG. 17, and adds the basic steering angle 4 and the correction angle 4 to calculate the total steering angle. The correction angle 4 is a correction angle stored at the end of the previous turn of the turn type “4”, as described later.

  The processes in steps S50 to S65 are the same as those in the first embodiment, but differ in the method of determining the basic steering angle at the time of turning, as described below.

  With reference to FIG. 14, an example of a method of determining the steering angle θ2 (basic steering angle) at the time of the pivot turn in the case of [90 ° left turn and no cargo] will be described. As shown in FIG. 14, in the left 90 ° pivot turn, the center of the left driven wheel 8Lc of the autonomous vehicle 1 is shifted from the center axis Y1c of the guide line Y1 by a distance D2A (from the center of the right driven wheel 8Rc to the center of the left driven wheel 8Lc). (1/2) of the distance of the left driven wheel, and turns (substantially) 90 ° in the counterclockwise direction around the left driven wheel center 8Lc. Here, the length of a virtual straight line VL2 from the center 8Lc of the left driven wheel, which is the center of the turn, to the center 8Dc of the drive steering wheel is a length R2, and a virtual circle having a radius R2 around the center 8Lc of the left driven wheel is assumed. Let it be a circle VC2. The tangent to the virtual circle VC2 at the drive steering wheel center 8Dc is defined as a virtual tangent S2. The angle (the angle on the side in the turn direction) formed by the virtual tangent line S2 and the guide line X2 is the steering angle θ2 (corresponding to the basic steering angle 4 in this case). If various states such as the steering angle of the drive steered wheels 8D are in the ideal state, when the turn is completed, the position of the left driven wheel center 8Lc is at the end of the turn, as shown in [End of turn in ideal state]. The position coincides with the position of the left driven wheel center 8Lc shown in FIG. At this time, the front detection means center 2Ac and the rear detection means center 2Bc are on the center axis Y1c of the guide line Y1 (when the predetermined distance E1 shown in FIG. 16 is set to zero). However, since there are actually various errors including the steering angle, when the turn is completed, the position of the left driven wheel center 8Lc is, as shown in [at the end of actual turn] in FIG. The position is shifted from the position of the left driven wheel center 8Lc shown in FIG. 14, and the autonomous vehicle 1 is inclined with respect to the post-turn guidance line Y1.

  The processing in steps S70 to S80 is the same as in the first embodiment. As described above, in the second embodiment, when the turn is a pivot turn, an error occurs in the steering angle, and a shift distance (distance E2) corresponding to the shift angle θe occurs in the attitude of the autonomous vehicle after the end of the turn. At this time, a learning angle is calculated so as to cancel the misalignment distance (distance E2) (so that the misalignment distance does not occur) and to use the obtained amendment angle in the next turn. As a result, a turn error can be automatically corrected. Further, by setting an angle smaller than the offset angle (for example, an angle that is 1/10 of the offset angle) smaller than the offset angle for offsetting the offset distance (distance E2) at one time, the offset distance (distance E2) in the next turn. Is not canceled out once, but the deviation distance is gradually reduced in a plurality of turns, so that erroneous learning can be prevented. Also, by having basic steering angles 1 to 4 and correction angles 1 to 4 corresponding to the types of turns of left turn or right turn, with or without cargo, depending on the state of the load on the drive steered wheels and the like. , The turn error can be automatically corrected more accurately.

● [Third embodiment (example of left 90 ° program steering) (FIGS. 18 to 22)]
In the third embodiment, the turn at the intersection is a turn called program steering, in contrast to the first embodiment in which the turn at the intersection is a spin turn. In the spin turn of the first embodiment, at the time of turn, the vehicle temporarily stops at an intersection from a forward (or backward) state, turns at that point, stops turning when facing the traveling direction, and performs forward (or reverse). Make a turn in the order of restarting. On the other hand, in the program steering according to the third embodiment, as described later, during the turn, the forward (or reverse) state is continued and the steering angle is gradually increased from just before the intersection, and the guidance before the turn is guided. The difference is that after gradually leaving the line, the vehicle gradually approaches the guide line at the turn destination while gradually reducing the steering angle. Also, the processing procedure is different from the flow chart of the first embodiment shown in FIG. 4, as shown in the flow chart of FIG. The basic addition angle and the correction addition angle are stored as angles dedicated to program steer, as shown in FIG. Further, in the program steering, a 90 ° turn is assumed, but a 180 ° turn is not assumed (turning 180 ° greatly deviates from the guide line), so that the basic addition angle and the correction addition angle are each four. This is also different from the first embodiment. Hereinafter, these differences will be mainly described. In the following description, an example of a state in which the autonomous traveling vehicle 1 does not hold a load will be described.

  As shown in the flowchart of FIG. 18, when the processing is started, the control device proceeds to step S10. Steps having the same reference numerals as those in the flowchart shown in FIG. 4 indicate that the processing contents are the same.

  In step S10, as in the first embodiment, the control device determines the center of the front detection means 2Ac (see FIG. 2) of the front guidance line detection means 2A and the center of the rear detection means 2B of the rear guidance line detection means 2B. By controlling the steering motor 52 and the drive motor 51 (see FIG. 2) such that the central axis X2c of the guide line X2 is located at 2Bc (see FIG. 2), the steering angle and drive of the drive steered wheels are controlled. Then, the autonomous traveling vehicle 1 is moved along the guidance line X2, and the process proceeds to step S17. The state in which the autonomous vehicle 1 is moving along the guidance line X2 is as shown in FIG. The virtual turn path VT1 in FIGS. 19 to 21 shows a virtual turn path, and a turn intermediate marker MC1 is arranged at a position corresponding to the vicinity of the center of the virtual turn path VT1.

  In step S17, the control device determines whether or not the vehicle has reached the turn start position. If it is determined that the vehicle has reached the turn start position (Yes), the process proceeds to step S25, and if the vehicle has not reached the turn start position ( No) returns to step S10. Specifically, as shown in FIG. 20, after detecting the left marker ML1 by the left marker detecting means 2L, the control device reaches the turn start position at a position moved along the guide line X2 by the distance D3. Is determined, and the program steer turn process after step S25 is executed. Note that the distance D3 and the distance D3A shown in FIG. 20 are set as appropriate.

  In step S25, the control device determines whether the turn at the current intersection (in this case, the intersection X2Y1) according to the preset (programmed) travel route is a right turn, If it is a right turn (Yes), the process proceeds to step S35A, and if it is not a right turn (No, left turn), the process proceeds to step S35E. The right turn and the left turn are one of the types of turns.

  When proceeding to step S35A, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detecting means 2C (see FIG. 2). If there is a cargo (Yes), the control device proceeds to step S40A and there is no cargo. In the case (No), the process proceeds to Step S40B. When proceeding to step S35E, the control device determines the presence or absence of a cargo based on the detection signal from the cargo detecting means 2C. If there is a cargo (Yes), the process proceeds to step S42E, and if there is no cargo (No), Proceed to step S42F.

  When proceeding to step S40A, the control device substitutes (stores) “1” (90 ° right, with cargo) for the turn type, and proceeds to step S47. When proceeding to step S40B, the control device substitutes (stores) “2” (right 90 °, no cargo) for the turn type, and proceeds to step S47. When proceeding to step S42E, the control device substitutes (stores) “3” (90 ° left, with cargo) for the turn type, and proceeds to step S47. When proceeding to step S42F, the control device substitutes (stores) “4” (90 ° left, no cargo) for the turn type, and proceeds to step S47.

  Note that the control device has storage devices (ROM and RAM), and the ROM of the storage device stores the program of this processing and the basic addition angles 1 to 4 in the program steer basic addition angle shown in FIG. ing. For example, in the case of [90 ° turn left and no cargo] in the program steer, the basic addition angle 4 includes the steering angle of the drive steering wheel 8D every time a certain distance (or a certain time) elapses from the start of the turn. Is stored in this case (corresponding to the basic addition angle 4 in this case). Further, the correction addition angles 1 to 4 in the program steering correction addition angle shown in FIG. 22 are stored in the RAM (or FlashROM) of the storage device. The correction addition angles 1 to 4 can be rewritten. For example, the correction addition angle 4 is a certain distance (or a certain time) from the start of the turn in the case of [90 turn left and no cargo] in the program steer. An angle for correcting the steering angle θ3 (basic addition angle before correction) to be added to the steering angle of the drive steered wheel 8D is stored each time it elapses. The method of calculating the correction addition angle will be described later.

  In step S47, the control device reads the basic addition angle (n) and the correction addition angle (n) corresponding to the turn type (n), calculates the total addition angle (basic addition angle + correction addition angle), and then proceeds to step S52. Proceed to. In the case where the autonomous traveling vehicle 1 without cargo turns the intersection X2Y1 by 90 ° to the left, the turn type is “4”. Therefore, the control device determines that the basic addition angle 4 in the program steering basic addition angle shown in FIG. And the correction addition angle 4 in the program steering correction addition angle shown in FIG. 22 is read, and the basic addition angle 4 and the correction addition angle 4 are added to calculate the total addition angle. Note that the correction addition angle 4 is a correction addition angle stored at the end of the previous turn of the turn type “4”, as described later.

  In step S52, the control device sets “steering angle <−steering angle + total addition” every time a certain distance (or a certain time) elapses while continuing to move forward (or move backward) (while driving the drive steered wheels). Angle ”is determined, the steered wheels are steered at the determined steering angle, and the process proceeds to step S54. That is, every time a predetermined distance (or a predetermined time) elapses, the steering angle is gradually increased, and the trace is traced from the turn start position on the guide line X2 to the turn intermediate marker MC1 in the virtual turn path VT1 shown in FIG. I will do it.

  In step S54, the control device determines whether the vehicle has reached the intermediate position of the virtual turn path VT1. If it is determined that the vehicle has reached the intermediate position (Yes), the control device proceeds to step S56, and has not reached the intermediate position. If it is determined (No), the process returns to step S52. Specifically, the control device determines whether or not the turn intermediate marker MC1 has been detected based on the detection signal from the front guide line detection means 2A. If the turn intermediate marker MC1 has been detected (Yes), the process proceeds to step S56, and the detection is performed. If not (No), the process returns to step S52.

  When the process proceeds to step S56, the control device sets “steering angle <−steering angle” every time a predetermined distance (or a predetermined time) elapses while continuing to advance (or reverse) (while driving the driving steered wheels). -Comprehensive addition angle "is determined, the steered wheels are steered at the determined steering angle, and the process proceeds to step S60. That is, every time a fixed distance (or a fixed time) elapses, the steering angle is gradually reduced so as to trace from the turn intermediate marker MC1 to the guide line Y1 in the virtual turn path VT1 shown in FIG. Go.

  In step S60, the control device determines whether it is time to end the turn. If it is determined that the turn is to be ended (Yes), the control proceeds to step S70; otherwise, the process returns to step S56. . In step S60, specifically, the control device determines that the distance between the guide line Y1 at the turn destination (the center axis Y1c of the guide line Y1) and the center 2Bc of the rear-side detection means, and which gradually decreases, is obtained. When the distance is within a predetermined distance E1 (an end determination distance, for example, about -10 [mm] to +10 [mm]) (see FIG. 21), it is determined that the turn is ended. For example, when the sign is (-), it indicates that the center 2Bc of the rear detection means is on the left side of the center axis Y1c of the guide line Y1, and when the sign is (+), the center 2Bc of the rear detection means is the guide line Y1. On the right side of the center axis Y1c.

  The values of the basic addition angles 1 to 4 are determined based on a certain time (or a certain distance) for adding the steering angle, a value of the distance D3A, and the like. However, since there are actually various errors including the steering angle, when the turn is completed, as shown in [Actual end of turn] in FIG. The autonomous vehicle 1 is in an inclined state.

  In step S70, the control device detects a displacement distance (distance E2) corresponding to the displacement angle θe in the state shown in FIG. 21, and proceeds to step S77. Specifically, the control device detects the distance E2 between the center 2Ac of the front detection means and the center axis Y1c of the guide line Y1 at the turn destination, and detects the distance E2 between the center 2Bc of the rear detection means and the center line Y1c of the guide line Y1 at the turn destination. Is detected. Further, a distance LAB from the center 2Ac of the front detection means to the center 2Bc of the rear detection means is stored in advance in the storage device of the control device. In this case, the deviation angle θe is the angle between the guidance line (the guidance line Y1 in the example of FIG. 21) and the front-rear direction of the autonomous vehicle 1 when it is determined that the turn has been completed in step S60. , Sin θe = [(distance E1 + distance E2) / distance LAB]. Since the distance E1 is so small that it can be ignored, the distance E1 may be approximated as sinθe ≒ [distance E2 / distance LAB], or the distance E2 (deviation distance) ≒ distance LAB * sinθe.

  In step S77, the control device converts the offset angle for preventing the shift distance (distance E2) from being generated from the shift distance (distance E2), and corrects the addition angle based on the converted offset angle (for example, 1 of the offset angle). / 10 (the number obtained by adding the steering angle in step S52), and the process proceeds to step S80. Note that the correction addition angle converted from the shift distance (distance E2) is corrected depending on whether the center 2Ac of the front detection unit is on the right side or the left side of the center axis Y1c of the guide line Y1 in the example of FIG. The sign of the addition angle is different. Then, in step S80, the control device stores the obtained correction addition angle in the correction addition angle (n) corresponding to the turn type (n), and returns to step S10. For example, when the turn type is “4”, the obtained correction addition angle is stored in the correction addition angle 4, and in the case of the next turn type “4”, the value of the correction addition angle 4 is used.

  As described above, in the third embodiment, when the turn is the program steer, an error occurs in the steering angle that changes every moment, and the shift distance (distance) according to the shift angle θe in the attitude of the autonomous vehicle after the end of the turn. When E2) occurs, a learning control is performed such that a correction addition angle is obtained so as to cancel the deviation distance (distance E2) (so that the deviation distance does not occur), and the obtained correction addition angle is used in the next turn. Perform This makes it possible to automatically correct a turn error. In addition, by setting an angle smaller than the offset angle at which the offset distance (distance E2) is canceled at one time as the correction addition angle, the offset distance (distance E2) is not canceled at one time at the next turn, but a plurality of times. In this turn, the deviation distance is gradually reduced, so that erroneous learning can be prevented. In addition, by having basic addition angles 1 to 4 and correction addition angles 1 to 4 corresponding to the type of turn of left turn or right turn, with or without cargo, depending on the state of the load on the drive steering wheel, etc. Thus, the turn error can be automatically corrected more accurately.

  The autonomous vehicle of the present invention is not limited to the configuration, structure, appearance, shape, processing procedure, and the like described in the present embodiment, and various changes, additions, and deletions are possible without changing the gist of the present invention. is there.

  Further, the autonomous traveling vehicle of the present invention is not limited to the use of transporting products or parts in a manufacturing plant, and can be applied to various autonomous traveling vehicles used for various applications.

  The numerical values used in the description of the present embodiment are merely examples, and the present invention is not limited to these numerical values.

DESCRIPTION OF SYMBOLS 1 Autonomous vehicle 1J Center axis 2A Front guidance line detection means 2Ac Front detection means center 2B Rear guidance line detection means 2Bc Rear detection center 2C Cargo detection means 2L Left marker detection means 2R Right marker detection means 8C Caster wheel 8D Drive Steering wheel 8Dc Driving steering wheel center 8L Left driven wheel 8Lc Left driven wheel center 8R Right driven wheel 8Rc Right driven wheel center 8Pc Left and right driven wheel center 10 Reach 50 Control device 51 Drive motor (drive means)
52 Steering motor (steering means)
60 Fork 61 Pump motor 62 Hydraulic pump 70 Mast a, b Cargo K1 Travel route MC1 Turn intermediate marker ML1 to ML4 Left marker MS1, MS2 Stop marker SE1 Equipment X1, X2 Lead line Y1, Y2 Lead line X1Y1, X1Y2, X2Y1, X2Y2 Intersection X2c, Y1c Center axis θ1, θ2 Steering angle θe Shift angle E2 Distance (shift distance)

Claims (2)

An autonomous traveling vehicle that moves according to a traveling route set along a guide line provided in advance,
A front-side guide line detecting means arranged in front of the autonomous vehicle to detect the guide line,
A rear guide line detecting means arranged behind the autonomous vehicle to detect the guide line,
A driven wheel fixed in the front-rear direction of the autonomous vehicle and provided rotatably in a pair of left and right in front or behind the autonomous vehicle,
The vehicle has a steering device capable of changing an angle of the autonomous vehicle with respect to the front-rear direction, and is a driving steering wheel driven by a driving device, wherein the driven wheel is provided rearward, and the driven wheel is provided rearward. In the case where it is provided in the front, the driving steering wheel provided,
Based on the detection signal from the front guide line detecting means, the detection signal from the rear guide line detecting means, and the travel route, the driving means and the steering means are controlled, and the driving means and the steering means are controlled along the guide line. A control device for moving the autonomous traveling vehicle according to a traveling route,
The traveling route has an intersection where the plurality of guidance lines intersect,
There are a plurality of types of turns at intersections according to the traveling route, including left and right directions of turning.
The autonomous traveling vehicle has a cargo detection means for detecting the presence or absence of a cargo,
The control device includes:
When turning at an intersection according to the traveling route, the steering unit and the driving unit are based on a steering angle set in advance corresponding to the intersection of the traveling route and a correction angle for correcting the steering angle. Control and turn at the intersection,
When it is determined that the intersection has been turned, a deviation distance corresponding to an angle formed between the guidance line at the end of the turn and the longitudinal direction of the autonomous vehicle is corrected by steering based on the correction angle at the next intersection. And
The control device includes:
The steering angle preset in accordance with the type of turn and the presence or absence of the load, and the correction angle corresponding to the type of turn and the presence or absence of the load are stored,
When turning at an intersection according to the traveling route, the steering means and the driving means are controlled based on the type of turn and the steering angle and the correction angle corresponding to the presence or absence of the cargo,
When it is determined that the intersection has been turned, the correction angle corresponding to the type of turn and the presence or absence of the load is changed based on the shift distance, and the changed correction angle is stored.
Autonomous vehicles. The autonomous vehicle according to claim 1 ,
The control device includes:
When turning at an intersection according to the traveling route, an angle smaller than the angle that offsets the deviation distance detected in the previous turn, in which the type of turn and presence / absence of a load in the current turn are the same, in the current turn, The correction angle used at the time,
Autonomous vehicles.