JP2010018054A - Autonomous turning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autonomous turning device capable of properly steering with a steering wheel without being influenced by a floor or the like on which a vehicle grounds. <P>SOLUTION: The autonomous turning device 2 is provided with a position detection means 6 detecting a starting point at which a vehicle starts turning, a distance detection means 8 detecting a distance the vehicle travels, a steering device 10 steering the steering wheel 36, an angle detection means 12 detecting a steering angle steered by the steering wheel 36, a storage means 14 storing turning data in which an accumulation value of distances the vehicle travels is corresponded to a target steering angle of the steering wheel 36 when the vehicle turns, and a control device 16 controlling the operation of the steering device 10. The control device 16 operates the steering device 10 so that the steering angle of the steering wheel 36 coincides with the target steering angle of the turning data at a time when the distance the vehicle travels from the starting point reaches to the accumulation value of the turning data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an autonomous turning device that turns a vehicle that travels according to a preset stroke.

As shown in FIG. 5, traveling guides 28 and 30 that are orthogonal to each other are embedded in a floor or the like. The vehicle 32, which is an automatic guided vehicle traveling in the direction of arrow F, detects the traveling guide 28 with the two guide sensors 34 attached to the front and rear portions thereof, and travels straight along the traveling guide 28. When the steering wheel 36 of the vehicle 32 reaches the point A, the vehicle 32 is stopped, and the steering wheel 36 is steered so as to be in a posture represented by a virtual line. Thereafter, when the vehicle 32 is started, the vehicle 32 turns. The figure
A trajectory 38 when the vehicle 32 turns 90 ° and a trajectory 40 of the steering wheel 36 are shown. Subsequently, when the steering wheel 36 of the vehicle 32 reaches the point B, the vehicle 32 is stopped again, and the steering wheel 36 is stopped.
Return to the direction of straight ahead. In other words, the steering wheel 36 is steered so as to be parallel to the traveling guide 30. Thereafter, when the vehicle 32 is started, the vehicle 32 is moved to the two guide sensors 34.
The travel guide 30 is detected by the above and travels straight along the travel guide 30.

While the vehicle 32 is turning as described above, the guide sensor 34 does not detect the travel guides 28 and 30. The autonomous turning described below refers to the vehicle 32 regardless of the travel guides 28 and 30.
Means that the steered wheel 36 is steered to turn. Further, Patent Document 1 detects a turning angle that is a posture of the vehicle with a gyroscope or the like when the vehicle starts autonomous turning,
A technique for determining the timing at which the vehicle finishes turning in light of this turning angle is disclosed.
JP 2003-241837 A

FIG. 6 is a plan view in which changes in posture of the same vehicle 32 are overlapped in the process of turning. An automated guided vehicle operating in an automatic warehouse or the like has the following problems because it is steered while traveling.
That is, steering is started at the same time as the steered wheel 36 passes through the point A, but a certain amount of operation time is required until the steered wheel 36 is steered to a predetermined steering angle. The same applies when returning the steered wheels 36 to the straight direction. Trajectories of the vehicle 32 and the steering wheel 36 that continue to travel during this time are indicated by dotted lines 39 and 41, respectively, and a so-called delay in turning of the steering wheel 36 occurs. If this is significant, the guide sensor 34 is displaced from above the travel guide 30, and the travel guide 30 cannot be detected by the guide sensor 34.

Further, since the steering device that steers the steered wheels 36 receives frictional force as a reaction force of steering from the floor or the like on which the steered wheels 36 are grounded, the above-described operation time tends to be delayed as the friction coefficient of the floor or the like increases. is there. However, since the friction coefficient of the floor or the like is an indeterminate element, it is difficult to quantitatively predict the turning delay of the steered wheels 36. For this reason, in order to bring the trajectory (dotted line 39) of the vehicle 32 steered while traveling closer to the trajectory 38, the steering device operates by groping so that steering is started slightly before the steering wheel 36 passes the point A. You have to adjust the timing.

Therefore, an object of the present invention is to provide an autonomous turning device that can be appropriately steered without being affected by a floor or the like on which a steered wheel contacts the ground.

In order to achieve the above object, the present invention provides an autonomous turning device that steers the steering wheel in order to turn the vehicle during a travel of the vehicle having the steering wheel, wherein the vehicle starts to turn. Position detecting means for detecting; distance detecting means for detecting the distance traveled by the vehicle;
Steering device for steering the steered wheel, angle detection means for detecting a steer angle at which the steered wheel is steered, and target steering of the steered wheel when the vehicle turns based on a cumulative value of the distance traveled by the vehicle A storage means that records turning data corresponding to a corner; and a control device that controls the operation of the steering device, and when the distance traveled by the vehicle from the starting point reaches a cumulative value of the turning data, The control device operates the steering device so that a steering angle of the steered wheel matches a target steering angle of the turning data.

Further, the present invention is characterized in that the storage means records a plurality of cumulative values that sequentially increase and a plurality of target steering angles determined for each cumulative value.

According to the autonomous turning device of the present invention, the starting point at which the vehicle should start turning is detected by the position detecting means, and at the same time, the distance detecting means detects the distance traveled by the vehicle from the starting point.
When this distance reaches the cumulative value of the turning data, the control device operates the steering device so that the actual steering angle of the steered wheels matches the value of the target steering angle of the turning data. As a result, it is possible to solve the problem that the steering wheel is delayed or the steering angle of the steering wheel precedes the target steering angle. Therefore, according to the autonomous turning device, the steered wheel can be appropriately steered regardless of the situation of the floor where the steered wheel is installed, the material of the steered wheel, or the size of the grounding area of the steered wheel. In addition, the adjustment work of determining the operation timing of the steering device depending on the experience or intuition of the operator can be almost omitted.

Furthermore, in the autonomous turning device according to the present invention, the storage unit records a plurality of cumulative values that increase sequentially and a plurality of target steering angles determined for each cumulative value as turning data. Therefore, every time the distance traveled by the vehicle from the starting point increases, the control device operates the steering device so that the actual steering angle of the steered wheels matches the target steering angle value of the turning data. Even if there is a slight deviation in the steering angle while the vehicle is turning autonomously, this can be corrected repeatedly. Therefore, according to the autonomous turning device, the vehicle that has finished the autonomous turning can be made to accurately follow the preset stroke.

FIG. 1 shows an outline of the autonomous turning device 2 that steers the steering wheel 36 during the travel of the vehicle having the steering wheel 36. The traveling guide is embedded in the floor or the like where the steering wheel 36 is grounded, and the guide sensor is attached to the vehicle 32 shown in FIG. The autonomous turning device 2 includes a position detection unit 6 that detects a starting point 4 at which the vehicle 32 starts turning, a distance detection unit 8 that detects a distance traveled by the vehicle 32, a steering device 10 that steers the steering wheel 36, Angle detection means 12 for detecting the steering angle at which the steered wheels 36 are steered, and storage means 1 for recording turning data described later.
4 and a control device 16 mainly composed of a computer.

The steering device 10 supports the axle 18 of the steering wheel 36 with an arm 20 and rotates the arm 20 around a vertical axis by the rotational force of a steering motor 22. The steering wheel 36 is steered by rotating together with the arm 20. Further, the steering device 10 includes a driving motor 24 that transmits a driving force to the steering wheel 36 via a gear train built in the arm 20. Angle detection means 12
Is a potentiometer that detects an angle of rotation of the arm 20 by the steering device 10 and transmits the detected angle to the control device 16. The distance detection means 8 is a rotary encoder that detects a rotation angle at which the drive motor 24 rotates, and this rotation angle is converted into a distance traveled by the vehicle 32 by the control device 16.

The traveling guide is an induction wire or magnet that is energized with an alternating current, and the guide sensor is configured such that the pickup coil 35 is paired above the induction wire. When the vehicle 32 travels straight along the travel guide, the pair of pickup coils 35 are moved from the travel guide.
However, when the vehicle 32 deviates in the vehicle width direction with respect to the travel guide, a potential difference is generated between the pair of pickup coils 35. At this time, the control device 16
The steering apparatus 10 is steered so that the vehicle 32 is guided to a position where no potential difference occurs. When the travel guide is the magnet, the guide sensor detects the center of the magnetic field,
Steering wheel 36 is steered so that vehicle 32 passes through the center of the magnetic field.

The position detecting means 6 detects a permanent magnet embedded in a place corresponding to the starting point 4 such as a floor with a pickup coil 35. The starting point 4 means a point that the position detection means 6 can identify during the travel of the vehicle 32. The storage means 14 records the cumulative value of the distance traveled while the vehicle 32 is turning and the target steering angle of the steered wheels 36 when the vehicle 32 turns.
M. The accumulated value is the distance that the steered wheel 36 moves from the start point 4 and is the length from the start point 4 of the curve 26 that represents the trajectory of the steered wheel 36. The target steering angle is a radius r for turning the vehicle 32,
This value is calculated based on the turning angle φ of the vehicle 32 and the wheel base d.

As shown in FIG. 3, the steering angle θ is an angle of the steering wheel 36 with respect to the vehicle 32, and the steering wheel 3
The time when 6 turns in the direction in which the vehicle 32 goes straight is defined as 0 degrees. An increase in the value of θ means that the steering angle is increased. Further, when the steering wheel 36 is steered so that the vehicle moving forward in the direction of arrow F turns right, the sign of the steering angle θ becomes +, and when the steering wheel 36 is steered so that the vehicle turns left. The sign of the steering angle θ is −. The turning data is obtained by associating the cumulative value and the target steering angle described above with each other. Table 1 shows that a plurality of cumulative values Xo that increase sequentially correspond to a plurality of target steering angles θo calculated for each of these cumulative values Xo.

Next, the autonomous turning of the vehicle by the autonomous turning device 2 will be described. The following S1 to S6 are:
It refers to the steps of the flowchart of FIG.

As shown in FIG. 2, the vehicle 32 goes straight in the direction of arrow F, and the control device 16 recognizes that the steering wheel 36 has reached the starting point 4 by the pickup coil 35 (S1). At the same time,
The control device 16 causes the steering device 10 to start the steering wheel 36 (S2). The steered wheel 36 shown in the figure is in a posture steered in the + θ direction of FIG. 3. As the vehicle 32 further travels, the control device 16 determines the steering wheel 3 based on the rotation angle of the drive motor 24 detected by the distance detection means 8.
The actual running distance X traveled by the vehicle 32 is measured from the time when 6 reaches the starting point 4 (S3).

When the actual travel distance X reaches the cumulative value Xo of the turning data, the control device 16 compares the actual steering angle θ of the steered wheel 36 with the target steering angle θo of the turning data (S4), and the steering angle. The steering device 10 is operated so that θ matches the value of the target steering angle θo (S5). For example, actual running distance X
If the actual steering angle θ is 7.1 degrees when is 15 mm, the control device 16 steers the steering wheel 36 in the direction in which the value of θ increases by 0.4 degrees, and the [0004] -th turn Target steering angle of data θo
= The steering angle θ is matched to 7.5 degrees. Alternatively, in the above example, the steering wheel 36 is steered by the vehicle 32.
If the actual steering angle θ exceeds the target steering angle θo, the control device 16 steers the steering wheel 36 in the direction in which the value of θ decreases, and sets the steering angle θ to 7.5. Match the degree.

By the operation of the steering device 10 described above, it is possible to eliminate the delay in turning the steering wheel 36 due to the frictional force between the steering wheel 36 and the floor. For this reason, the guide sensor of the vehicle 32 that has finished the autonomous turn does not deviate from the upper side of the travel guide, and the vehicle 32 does not deviate from a preset stroke.

Further, according to the autonomous turning device 2, the adjustment work of determining the operation timing of the steering device 10 depending on the operator's experience or intuition can be omitted. This effect is also achieved when the frictional force between the steering wheel 36 and the floor is small. That is, even if the steering reaction force received by the steering device 10 is too small, the steering angle θ of the steered wheels 36 does not precede the target steering angle θo. Therefore, according to the autonomous turning device 2, the steering wheel 36 can be appropriately steered regardless of the condition of the floor surface, the material of the steering wheel 36, or the size of the grounding area of the steering wheel 36. it can.

Further, the control device 16 accesses the storage means 14 every time the actual running distance X increases (S6).
The steering device 10 can be operated so that the actual steering angle θ of the steered wheels 36 matches the value of the target steering angle θo of the turning data (S5). For this reason, the autonomous turning device 2 has the vehicle 32.
Even if a slight deviation occurs in the steering angle θ while the vehicle is autonomously turning, there is an advantage that this can be corrected repeatedly.

Finally, the control device 16 sets the steering angle θ to the target steering angle θo = 0 ° of the [0050] -th turning data.
The steering device 10 is operated so as to match (S5). When this operation is completed, the autonomous turning of the vehicle 32 by the autonomous turning device 2 ends.

It should be noted that the present invention can be implemented in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Moreover, you may implement with the form which substituted any invention specific matter to the other technique within the range which the same effect | action or effect produces.

The present invention is a technique useful for autonomous turning of any vehicle regardless of the number of steered wheels, the arrangement of steered wheels, or the use of the vehicle.

The block diagram which shows the structure of the autonomous turning apparatus which concerns on embodiment of this invention. The top view which shows the process in which the vehicle which steers a steering wheel by the autonomous turning apparatus which concerns on embodiment of this invention turns. The top view explaining the steering angle of the steered wheel applied to the autonomous turning apparatus which concerns on embodiment of this invention. The flowchart explaining operation | movement of the autonomous turning apparatus which concerns on embodiment of this invention. The top view explaining the process in which a vehicle turns. The top view showing the change of the posture in the process in which a vehicle turns.

Explanation of symbols

2 ... autonomous turning device, 4 ... starting point, 6 ... position detection means, 8 ... distance detection means, 10 ... steering device,
12 ... Angle detection means, 14 ... Storage means, 16 ... Control device.

Claims (2)

An autonomous turning device that steers the steering wheel in order to turn the vehicle during a travel of a vehicle having steering wheels,
Position detecting means for detecting a starting point at which the vehicle starts turning, distance detecting means for detecting a distance traveled by the vehicle, a steering device for steering the steering wheel, and a steering angle at which the steering wheel is steered Angle detecting means for detecting, storage means for recording turning data in which the cumulative value of the distance traveled by the vehicle corresponds to a target steering angle of the steering wheel when the vehicle turns, and operation of the steering device A control device for controlling,
When the distance traveled by the vehicle from the starting point reaches the cumulative value of the turning data, the control device causes the steering device so that the steering angle of the steering wheel matches the target steering angle of the turning data. Autonomous turning device characterized by operating. 2. The autonomous turning device according to claim 1, wherein the storage unit records a plurality of the cumulative values that sequentially increase and a plurality of the target steering angles determined for each cumulative value.

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