CN113615361A

CN113615361A - Working vehicle

Info

Publication number: CN113615361A
Application number: CN202010714719.7A
Authority: CN
Inventors: 堀田直岐; 川上修平; 小佐野光; 神谷寿; 飞田秀平; 铃木悠太
Original assignee: Iseki and Co Ltd
Current assignee: Iseki and Co Ltd
Priority date: 2020-05-07
Filing date: 2020-07-23
Publication date: 2021-11-09
Also published as: TW202142102A; TWI825346B; KR20210136792A; JP6988949B2; JP2021176273A

Abstract

A conventional work vehicle such as a rice transplanter cannot control the rotation of a vehicle body. The present invention provides a work vehicle, including: a steering member driving device (44) that drives the steering member (52); a control device (200) for controlling the steering member drive device (44); and a detection means for detecting a turning state of the vehicle body (10), wherein the control device (200) performs turning control when turning the vehicle body (10), and wherein the control device (200) performs turning state determination based on the detection result and controls the steering angle based on the turning state determination.

Description

Working vehicle

Technical Field

The present invention relates to a working vehicle such as a rice transplanter which travels in a farm field.

Background

There is known a rice transplanter comprising: the planting device can be arranged on the vehicle body in a lifting way; a steering motor that drives a steering wheel; and a control device that controls the vehicle body to move straight and turn by driving a steering wheel by a steering motor (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2008-92818

Disclosure of Invention

Problems to be solved by the invention

However, since the control accuracy of the rotation of the vehicle body is low, the continuous travel of the straight travel control in the next step cannot be performed with high accuracy.

In view of the above conventional problems, an object of the present invention is to provide a work vehicle capable of controlling the turning of a vehicle body.

Means for solving the problems

An aspect 1 of the present invention is a work vehicle including: a steering member driving device 44 that drives the steering member 52; a control device 200 for controlling the steering member driving device 44; and a detection means for detecting a turning state of the vehicle body 10, wherein the control device 200 performs turning control when turning the vehicle body 10, and the control device 200 performs turning state determination based on a result of the detection and controls a steering angle based on the turning state determination.

Claim 2 of the present invention is the work vehicle according to claim 1, characterized in that,

in order to cause the turning vehicle body 10 to travel straight again, the control device 200 controls the steering angle by changing the steering angle returning timing to return the steering angle based on the turning state determination.

Claim 3 of the present invention is the work vehicle according to claim 2, characterized in that,

the steering angle return timing can be adjusted based on a manual operation of adjusting a predetermined steering angle return level.

Claim 4 of the present invention is the work vehicle according to claim 1, characterized in that,

the control device 200 controls the steering angle by maintaining the steering angle at a constant angle until a turning state determination time at which the turning state determination is performed, and then changing the constant angle based on the turning state determination.

Claim 5 of the present invention is the work vehicle according to any one of claims 1 to 4,

the detection means is provided with a rear wheel revolution speed sensor 210 and a positioning system 300, and the measurement of the travel distance is started by the rear wheel revolution speed sensor 210 with the start of turning, and when the direction of the vehicle body 10 reaches a predetermined angle, if the travel distance is large, the positioning system 300 determines that turning is turning large, and if the travel distance is small, the positioning system 300 determines that turning is turning small.

Claim 6 of the present invention is the work vehicle according to any one of claims 1 to 4,

the detection means is provided with a rear wheel revolution speed sensor 210 and a positioning system 300, and measurement of the travel distance is started by the rear wheel revolution speed sensor 210 with the start of turning, and when the travel distance reaches a predetermined distance, if the change in the orientation of the vehicle body 10 from the start of turning is small, the positioning system 300 determines that turning is turning, and if the change in the orientation of the vehicle body 10 from the start of turning is large, the positioning system 300 determines that turning is turning.

ADVANTAGEOUS EFFECTS OF INVENTION

According to aspect 1 of the present invention, the turning control of the vehicle body can be performed.

According to aspect 2 of the present invention, in addition to the effect of aspect 1 of the present invention, highly accurate control can be realized.

According to aspect 3 of the present invention, in addition to the effect of aspect 2 of the present invention, control with high compatibility can be achieved.

According to aspect 4 of the present invention, in addition to the effect of aspect 1 of the present invention, highly accurate control can be realized.

According to aspect 5 of the present invention, in addition to the effect of any one of aspects 1 to 4 of the present invention, steering is controlled such that the machine body moves to the inside when it is determined that a turn is large, and steering is controlled such that the machine body moves to the outside when it is determined that a turn is small, thereby improving the turning accuracy.

According to aspect 6 of the present invention, in addition to the effect of any one of aspects 1 to 4 of the present invention, steering is controlled such that the machine body moves to the inside when it is determined that a turn is large, and steering is controlled such that the machine body moves to the outside when it is determined that a turn is small, thereby improving the turning accuracy.

Drawings

Fig. 1 is a perspective view of a rice transplanter according to an embodiment of the present invention.

FIG. 2 is a block diagram of a power transmission system of a rice transplanter according to an embodiment of the present invention.

FIG. 3 is a block diagram of a control system of a rice transplanter according to an embodiment of the present invention.

Fig. 4 is (a) an explanatory view of rotation control of the rice transplanter according to the embodiment of the present invention.

Fig. 5 is an enlarged explanatory view of rotation control of the rice transplanter according to the embodiment of the present invention.

Fig. 6 is an explanatory diagram of the reverse turning control of the rice transplanter according to the embodiment of the present invention.

Fig. 7 is a partial perspective view of a rice transplanter according to an embodiment of the present invention.

FIG. 8 is a partial plan view of a rice transplanter according to an embodiment of the present invention.

Fig. 9 is an enlarged partial plan view of the vicinity of the auxiliary wheel of the rice transplanter in accordance with the embodiment of the present invention.

In the figure: 10-vehicle body, 44-steering motor (steering member driving device), 52-steering wheel (steering member), 200-control device, 210-rear wheel rotation speed sensor, 300-positioning system.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, the same applies to some constituent elements, which are not shown in the drawings and may be seen through or omitted.

The rice transplanter of the present embodiment is an example of the work vehicle of the present invention or the invention related to the present invention.

In the embodiment of the modified example, for example, the work vehicle of the present invention or the invention related to the present invention may be an agricultural tractor.

The steering wheel 52 is an example of a steering member of the invention or inventions associated with the invention. The steering motor 44 is an example of a steering member driving device that drives the steering wheel 52 of the present invention or the invention related to the present invention.

The control device 200 is an example of a control device that controls the steering motor 44 of the present invention or inventions related to the present invention.

The vehicle body 10 is an example of a vehicle body of the invention or inventions related to the invention. The rear wheel rotation speed sensor 210 and the positioning system 300 are examples of the detection means for detecting the turning state of the vehicle body 10 according to the present invention or the inventions related to the present invention.

The auxiliary wheel 33 is an example of a single or a plurality of auxiliary wheels attached to at least one of the inner side and the outer side of the vehicle body 10 in the vehicle body left-right direction of the invention or the invention related to the invention.

The rear wheel 32 on the turn inner side is an example of a predetermined wheel of the invention or the invention related to the invention.

First, the structure and operation of the rice transplanter of the present embodiment will be specifically described with reference to fig. 1 and 2.

Here, fig. 1 is a perspective view of a rice transplanter according to an embodiment of the present invention, and fig. 2 is a block diagram of a power transmission system of the rice transplanter according to the embodiment of the present invention.

While the operation of the rice transplanter of the present embodiment is described, the travel control method of the invention related to the present invention will also be described.

The rice transplanter of the present embodiment is an 8-row riding mat seedling rice transplanter, and the planting device 100 includes four planting units each having a pair of two planting implements on the left and right.

The transplanter is not limited to a riding seedling transplanter for 8-row planting, and may be a riding potted seedling transplanter for 10-row planting, for example.

First, the basic configuration and operation of the rice transplanter of the present embodiment will be described. Therefore, the turning control and the like will be described in detail later.

The driver unit 50 includes a seat 51 provided above the engine 20.

A steering wheel 52 for operating the front wheels 31 is provided in front of the seat 51. Horizontal pedals are provided on both the left and right sides of the engine 20. The vehicle body 10 is provided with a standby seedling stage 101.

The running device 30 is a device that runs the vehicle body 10 by using the front wheels 31 and the rear wheels 32.

The leveling device 60 is a device for leveling a farm field by using a leveling rotor mechanism 61 and a leveling float mechanism 62.

A marker 80 for forming a straight line to be a target of a next planting route to a farmland is mounted to the vehicle body 10 so as to be able to be stored therein.

The planting device 100 is mounted to the rear side of the vehicle body 10 via the planting device lifting device 90.

The rotational power of the engine 20 mounted on the main frame is transmitted to a main transmission mechanism 41, which is an hst (hydro Static transmission) mechanism, and the like. The rotational power after the speed change in the main transmission mechanism 41 and the sub-transmission mechanism 42 is separated into the traveling power used in the traveling device 30 and the like and the external extraction power used in the planting device 100 and the like.

Part of the traveling power is transmitted to the left and right front wheel end housings to drive the pair of left and right front wheels 31, and the remaining traveling power is transmitted to the left and right rear wheel gearboxes 43 to drive the pair of left and right rear wheels 32. Part of the traveling power transmitted to the rear wheel gear box 43 is transmitted to the leveling device 60 and the fertilizer applying device 70.

Next, the structure and operation of the rice transplanter of the present embodiment will be described in more detail with reference mainly to fig. 1 to 3.

Here, fig. 3 is a block diagram of a control system of a rice transplanter according to an embodiment of the present invention.

The control device 200 is a device that performs various controls using not only the lever operation of the main shift lever 53, the sub shift lever 54, or the straight auxiliary lever 55 and the switch operation of the auxiliary mode switch 56, but also the detection results of the rear wheel rotation speed sensor 210 or the planting device elevation sensor 220.

The Positioning system 300 is a system for performing Positioning by using dgps (differential Global Positioning system) technology using a typical gps (Global Positioning system) which is a gnss (Global Navigation Satellite system).

Since the travel control must be performed in consideration of the size of the vehicle body 10, the responsiveness of the steering motor 44, the state of the farmland, and the like, it is difficult to perform precise travel control even if the positioning by the positioning system 300 is temporarily extremely accurate, and various attempts are known.

In the straight travel control, the coordinates of the point a corresponding to the start point of the straight travel in which the planting work is performed and the coordinates of the point B corresponding to the end point of the straight travel are registered in advance by the positioning system 300 that acquires the current direction information of the vehicle body 10. Then, the steering motor 44 is driven to perform steering so as to perform straight traveling based on a virtual line connecting the points a and B, thereby realizing straight traveling control.

However, since the on/off operation of the straight control is required every time the manual steering is required, the burden on the operator is not reduced, and operability and workability are not necessarily sufficient.

Therefore, it is desirable to realize not only the straight line control but also the rotation control for automatically performing the line alignment of the planting line distance, and the following basic rotation control is considered.

It is needless to say that the method of swing control described below can be used for various swing controls. Specifically, one of the various turning controls described above is a turning control that does not include a straight-ahead operation during turning, in which the turning angle is substantially constant during turning, and in which the turning path of the vehicle body 10 is a substantially semicircular path.

(A1) Next, the structure and operation of the rice transplanter of the present embodiment will be described in more detail with reference mainly to fig. 4 and 5.

Here, fig. 4 is (a) an explanatory view of rotation control of the rice planting machine according to the embodiment of the present invention, and fig. 5 is an enlarged explanatory view of rotation control of the rice planting machine according to the embodiment of the present invention.

The rice transplanter of the present embodiment is a rice transplanter in which the control device 200 performs rotation control when rotating the straight body 10.

Control device 200 performs turning state determination based on the detection result, and controls the steering angle based on the turning state determination.

For example, in the automatic rotation control of the rice transplanter, the operation of the rice transplanter is not performed in a straight line during the rotation, and the rotation is controlled while maintaining a constant steering angle α (for example, 45 degrees) during the automatic rotation. In the control of setting a turning path by the GPS and turning along the path, the control may be difficult and unstable. Further, when steering is performed during turning, the rotation of the rear wheel on the inside of the turning changes, and so-called Z-turn and other controls become unstable. By setting the steering angle to be constant, control is easy and versatility is large for various types of machine bodies. Since the steering angle is constant, the rotation of the turning inner rear wheel is stable, and it is possible to easily determine whether the turning is small or large when the number of rotations of the inner rear wheel is small, without adding a sensor or the like.

In order to cause the vehicle body 10 to travel straight again during turning, the control device 200 controls the steering angle by changing the steering angle returning timing to return the steering angle based on the turning state determination.

The steering angle returning timing is a timing at which the difference between the orientation of the turning vehicle body 10 and the orientation of the vehicle body 10 that is caused to travel straight again is lower than a predetermined steering angle returning level.

For example, the steering angle return level is 30 degrees.

The adjustment of the steering angle return timing can be performed based on a manual operation of adjusting a predetermined steering angle return level.

For example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dial operation of the threshold value adjustment device 400 based on experience of the operator.

The time when the turning state determination is performed is the time of the position of arrow a determined based on the orientation such as the orientation of the body or the right-angle orientation of the body, the distance, the time, the GNSS position, the vehicle speed, or the like. The turning state is determined based on the azimuth, distance, time, GNSS position, vehicle speed, or the like.

For example, the size of the turning locus can be determined with a time margin at the time of the position where the body orientation is 45 degrees, which is the difference between the orientation of the vehicle body 10 during turning and the orientation in which the vehicle body 10 is made to travel straight again.

When it is determined that the turning locus of the vehicle body 10 starting from the turning start position Ps on the straight line Lv0 as the preceding process line is the turning locus C0 of the standard size, the steering angle is returned at the time when the steering angle of the standard 30-degree steering angle is returned to the horizontal position P0 without changing the steering angle return timing. Even if the steering angle return timing is not changed, the vehicle body 10 can enter the straight traveling control transition region Z as it reaches the virtual line Lh0 immediately before the planting start line Lh, and therefore, smooth transition to the straight traveling control is performed for automatically moving the vehicle body 10 straight again along the straight traveling line Lv.

The transition from the turning control to the rectilinear control is performed, for example, at the time when the entry into the rectilinear control transition region Z is recognized based on the GNSS position.

In order to smoothly transit to the straight traveling control, it is desirable to realize a state in which not only the angle of penetration into the straight traveling line Lv but also the steering angle is not so much increased immediately before the straight traveling control transition region Z as the straight traveling line Lv as the next process line approaches.

The present inventors have reached a method of ensuring a smooth transition to such a straight traveling control regardless of a turning state that is likely to change due to the influence of a farmland state or the like by changing a turning angle returning timing for returning a turning angle based on turning state determination.

Specifically, the steering angle return timing is changed as follows based on the determination of the magnitude of the turning locus.

When it is determined that the turning locus is the turning locus C1 with a small turn, the turning angle is returned at a timing when the turning angle of 35 degrees larger than 30 degrees returns to the horizontal position Q1, for example, instead of the timing when the turning angle of 30 degrees returns to the horizontal position P1. In this way, even if the turning locus is the turning locus C1 with a small turn, the vehicle body 10 can travel close to the straight line Lv and enter the straight traveling control transition region Z, and therefore, a smooth transition to the straight traveling control is similarly performed.

When it is determined that the turning locus is the turning locus C2 of a large turn, the turning angle is returned at a timing when the turning angle of 25 degrees smaller than 30 degrees returns to the horizontal position Q2, for example, instead of the timing when the turning angle of 30 degrees returns to the horizontal position P2. In this way, even if the turning locus is the turning locus C2 which is turned greatly, the vehicle body 10 can enter the straight traveling control transition region Z without traveling away from the straight traveling line Lv, and therefore, smooth transition to the straight traveling control is similarly performed.

Of course, the change of the steering angle return timing may be performed based on the azimuth as described above, but may be performed based on the distance, time, GNSS position, vehicle speed, or the like so as to correct the movement path for smooth transition to the straight traveling control.

In the turning assist correction control using the rear wheel pulse, the turning inner side rear wheel pulse during turning is measured from the start of the automatic turning control in order to know the rear wheel rotation speed for determining the magnitude of the turning locus. The number of pulses on the inner side of the rear wheel during automatic rotation has little influence on sliding and the like, and it is possible to determine whether or not the rotation operation is performed normally.

In the automatic rotation control of the rice transplanter, the number of pulses of the rear wheel inside the rotation from the start of the automatic rotation control to the predetermined direction θ 0 of the orientation of the body is measured. θ 0 is set to 45 degrees or more. Whether or not to add correction of automatic revolution control is determined based on the rear wheel pulse number at the time point of the machine body orientation θ 0. When θ 0 is 45 degrees or less, even if correction is added to the automatic revolution control, the revolution accuracy may become oncoff due to the control.

When the number of pulses at this time is p1 to p2, it is determined that the rotation is normally performed, and the control is performed without performing the correction control. By setting the widths of p1 to p2 to the appropriate values of the rear wheel pulses on the inner side of the revolution in the automatic revolution control, the revolution accuracy can be improved without adding unnecessary correction control or the like.

When the pulse number p is not less than p2, the rotation is judged to be a big turn, and the rotation is controlled to be returned to the starting direction to delay so as to make the machine body to be close to the inner side, so as to start the planting alignment. When it is determined that the turning is a big turn from the rotation speed of the rear wheel, the turning is controlled to return to the starting position so that the machine body comes inside, and the planting start can be aligned, so that the turning accuracy can be improved.

When the pulse number p is p.ltoreq.p 1, the rotation is judged to be a small rotation, and the rotation is controlled to be returned to the starting direction to delay and advance the machine body to the outer side so as to start the alignment of the planting. When the rotation speed of the rear wheel is judged to be the small turning, the turning is controlled to return to the starting position so that the machine body comes to the outer side to align the planting start, thereby improving the turning precision.

The size of the turning locus may be determined based on the size of the rear wheel rotational speed at the time when the body orientation reaches the position of the predetermined angle in this way, but conversely, the size of the turning locus may be determined based on the size of the body orientation at the time when the rear wheel rotational speed reaches the position of the predetermined number of times. For example, when the size of the body orientation at the time when the rear wheel rotation speed reaches the position of the predetermined number of times is small, it may be determined that the turning is a large turn, and the turning is controlled so that the turning is delayed to return to the starting orientation and the body is moved inward so as to start the planting alignment.

As a result, the time at which the turning state determination is performed is determined based on a single or a plurality of physical quantities selected from the azimuth, the distance, the time, the GNSS position, the vehicle speed, and the like, and the turning state is determined based on the same physical quantities, but the combination of these physical quantities is arbitrary. For example, the time at which the turning state determination is performed may be determined based on the distance and the GNSS position, and the turning state determination may be performed based on the azimuth and the vehicle speed.

Further, the steering angle returning timing is changed based on a single or a plurality of physical quantities selected from the azimuth, the distance, the time, the GNSS position, the vehicle speed, and the like, but a combination of the physical quantity based on the control of the steering angle, such as the change of the steering angle returning timing, and the above-described physical quantity may be independently determined or may be dependently determined. For example, the time at which the turning state determination is performed may be determined based on time, the turning state determination may be determined based on the vehicle speed, and the steering angle return time may be changed based on the azimuth and the GNSS position.

The control device 200 may control the steering angle by changing the constant angle based on the turning state determination after the turning state determination time at which the turning state determination is performed is maintained so that the steering angle is the constant angle.

When the pulse number p is not less than p2, it is determined that the turning is a large turn, and the steering angle α, which is a constant angle, is controlled to be a small turn for increasing the deflection. When it is determined that the cornering is large based on the rotation speed of the rear wheels, the cornering accuracy can be improved by controlling the steering to be small.

When the pulse number p is p.ltoreq.p 1, it is determined that the turning is a small turn, and the steering angle α, which is a constant angle, is controlled to be a large turn. When it is determined from the rotation speed of the rear wheels that the cornering is small, the cornering accuracy can be improved by controlling the steering to be large.

The change of the constant angle such as the yaw increase or the yaw return of the steering angle α may be performed simultaneously with the turning state determination, and it goes without saying that it may be performed after 0.2 seconds of the turning state determination, for example.

In order to cause the turning vehicle body 10 to travel straight again, the control device 200 may control the steering angle by changing the steering angle returning speed for returning the steering angle based on the turning state determination.

Of course, the change of the steering angle returning speed may be performed simultaneously with the change of the steering angle returning timing instead of the change of the steering angle returning timing, so that the movement path can be corrected satisfactorily. For example, the body orientation of the return steering angle may be constant, or only the steering angle return speed may be changed.

The return of the steering angle may be performed simultaneously with the turning state determination, and it goes without saying that it may be performed after 0.2 seconds of the turning state determination, for example.

In the configuration capable of adjusting the steering angle returning speed, even if the time at which the turning state determination is performed is very close to the steering angle returning time, the steering angle can be returned without delay by increasing the steering angle returning speed.

(A2) Next, the structure and operation of the rice transplanter of the present embodiment will be described in more detail with reference mainly to fig. 6.

Here, fig. 6 is an explanatory diagram of the reverse turning control of the rice planting machine according to the embodiment of the present invention.

The rice transplanter of the present embodiment is a rice transplanter as follows: the control device 200 performs turning control when the vehicle body 10 that is traveling straight is stopped, retreated, stopped again, and turned.

When the vehicle travels backward from the point S1 to the point S2, the vehicle automatically or semi-automatically turns from the point S2 to the point S5 via the points S3 and R4.

Of course, it is also conceivable that the turning assist control is not started in a mode in which the HST is automatically controlled, such as the hole planting control and the approach hole control, in the turning control. This is because the HST may unexpectedly operate when the swing assist is started by the erroneous approach to the hole. Therefore, it is desirable to prevent unexpected HST action.

The rice transplanter of the present embodiment is a rice transplanter as follows: the control device 200 performs the straight traveling control before turning when the turning vehicle body 10 is made to travel straight, performs the turning control when the straight vehicle body 10 is made to turn, and performs the straight traveling control after turning when the turning vehicle body 10 is made to travel straight again.

Switching from the straight control before turning to the turning control is performed based on a manual operation.

Of course, the switching from the straight traveling control before the turning to the turning control is the same as the switching from the turning control to the straight traveling control after the turning, and an embodiment in which the switching from the line turning control to the straight traveling control after the turning is performed by a manual operation is considered as well as an embodiment in which the switching is performed automatically.

In order to cause the turning vehicle body 10 to travel straight again, the steering angle returning timing to return the steering angle is set to a timing before the straight travel control start timing of the straight travel control after the turning is started.

As described above, for example, the steering angle return level is 30 degrees.

As described above, for example, the steering angle return level may be reduced to 25 degrees or increased to 35 degrees by dial operation of the threshold value adjusting device 400 based on experience of the operator.

Industrial applicability

The work vehicle of the present invention can control the turning of the vehicle body, and is useful for the purpose of being used in a work vehicle such as a rice transplanter.

Claims

1. A work vehicle is provided with:

a steering member driving device (44) that drives the steering member (52);

a control device (200) for controlling the steering member drive device (44); and

a detection means for detecting a turning state of the vehicle body (10),

the control device (200) performs rotation control when rotating the vehicle body (10),

the work vehicle described above is characterized in that,

the control device (200) determines a turning state based on the result of the detection, and controls a steering angle based on the turning state determination.

2. The work vehicle according to claim 1,

in order to cause the vehicle body (10) to travel straight again during the turning, the control device (200) controls the steering angle by changing a steering angle returning timing at which the steering angle is returned based on the turning state determination.

3. The work vehicle according to claim 2,

4. The work vehicle according to claim 1,

the control device (200) controls the steering angle by maintaining the steering angle at a constant angle until a turning state determination time at which the turning state determination is performed, and then changing the constant angle based on the turning state determination.

5. The work vehicle according to any one of claims 1 to 4,

the detection means is provided with a rear wheel rotation speed sensor (210) and a positioning system (300), and when the direction of the vehicle body (10) reaches a predetermined angle, the measurement of the travel distance is started by the rear wheel rotation speed sensor (210) in accordance with the start of turning, and when the travel distance is large, the positioning system (300) determines that turning is a curve with large turning, and when the travel distance is small, the positioning system (300) determines that turning is a curve with small turning.

6. The work vehicle according to any one of claims 1 to 4,

the detection means is provided with a rear wheel rotation speed sensor (210) and a positioning system (300), and the measurement of the travel distance is started by the rear wheel rotation speed sensor (210) with the start of turning, and when the travel distance reaches a predetermined distance, if the change in the orientation of the vehicle body (10) from the start of turning is small, the positioning system (300) determines that turning is a curve with large turning, and if the change in the orientation of the vehicle body (10) from the start of turning is large, the positioning system (300) determines that turning is a curve with small turning.