JP2000142455A - Steering method of crawlered vihicle and steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a target vehicular turning motion automatically in response to a turning order value while adding the effect by a crawler slip. SOLUTION: A vehicular target turning angular velocity for the turning order value by a steering lever 15 is set advancely and the real turning angular velocity detected by a real turning angular velocity detection means is compared and calculated with the set target turning angular velocity and based on the deviation between these real turning angular velocity and the target turning angular velocity, a clutch oil pressure control signal and brake oil pressure control signal are outputted to a clutch control valve 31 and brake control valve 32 and control a vehicular turning force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for steering a tracked vehicle, such as a bulldozer, which controls a turning force of the vehicle by controlling clutches and brakes provided on left and right drive wheels. And a steering device.

[0002]

2. Description of the Related Art Conventionally, as a steering device for a tracked vehicle, there is known a steering device in which a clutch and a brake are provided on each of left and right driving wheels and the clutch and the brake are controlled to perform a left-right turning motion of the vehicle. Have been. In this steering apparatus, when the steering lever is operated in the right turning direction while the vehicle is running, the right clutch is released, the right brake is braked, only the right crawler belt stops, and the vehicle turns right. . When the steering lever is returned to the original position, the brake is released, the right clutch is engaged, and the vehicle goes straight. On the other hand, when the steering lever is operated in the left turning direction, the left clutch is released, the left brake is braked, only the left crawler belt stops, and the vehicle turns left.

[0003] By the way, as an example of a travel control device for automatically correcting a turning motion or a straight running of a vehicle, Japanese Patent Application Laid-Open No. 2-151576 and Japanese Utility Model Application Laid-Open No. HEI 3-151576 are disclosed.
There is one disclosed in US Pat. No. 53375. In the vehicle turning control apparatus described in the former publication (Japanese Patent Application Laid-Open No. 2-151576), the actual value of the yaw rate detected from the speed difference between the left and right wheels and the reference value of the yaw rate generated during the vehicle turning movement. A deviation from the value is calculated, and the transmission torque of a hydraulic clutch inserted between the left and right drive wheels and the engine is controlled in accordance with the deviation. Also, the latter publication (Japanese Utility Model Laid-Open Publication No. 3-53375).
In the travel control device for a hydraulically driven vehicle described in (1), an inertial sensor fixed to the vehicle detects an angular velocity around a gravitational axis accompanying turning while the vehicle is traveling, and integrates this detection signal to obtain an azimuth detection signal. In this manner, based on the deviation between the azimuth angle detection signal and the azimuth angle command signal given in advance,
The pump swash plate is controlled by controlling the electromagnetic control valve.

[0004]

However, in the apparatus described in Japanese Patent Application Laid-Open No. 2-151576,
Since the detection of the yaw rate is performed based on the speed difference between the left and right wheels, there is a problem that the slip of the crawler track cannot be reflected in the calculation of the turning force of the vehicle body, and the control accuracy is deteriorated accordingly. . On the other hand, the aforementioned Japanese Utility Model Laid-Open No. 3-53375
The device described in Japanese Patent Application Laid-Open Publication No. H11-209555 relates to a control technique for making a hydraulically driven vehicle travel straight, and is essentially different from a control technique for obtaining a desired turning radius of the vehicle as in the present invention. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and automatically performs a turning motion of a target vehicle according to a turning command value in consideration of the influence of crawler belt slip. It is an object of the present invention to provide a method and a steering device for a tracked vehicle that can be performed.

[0006]

In order to achieve the above object, a method for steering a tracked vehicle according to the present invention comprises providing a clutch and a brake on each of left and right drive wheels, and providing the clutch and the brake. A method for steering a tracked vehicle that controls the turning force of the vehicle by controlling the target turning angular velocity with respect to a preset turning command value of the vehicle, and using the detected actual turning angular velocity of the vehicle. The clutch and the brake are controlled based on a deviation between the actual turning angular velocity and the target turning angular velocity.

Further, a steering apparatus for a tracked vehicle according to the present invention for realizing the method for steering a tracked vehicle more specifically includes a clutch and a brake on each of left and right drive wheels, and the clutch and the brake. A steering apparatus for a tracked vehicle including a control valve for controlling a brake, wherein (a) target turning angular velocity setting means for setting a target turning angular velocity of the vehicle with respect to a predetermined turning command value, and (b) detecting an actual turning angular velocity of the vehicle. (C) comparing the actual turning angular velocity detected by the actual turning angular velocity detecting means with the target turning angular velocity set by the target turning angular velocity setting means, and calculating the actual turning angular velocity and the target turning. Turning force control for controlling a turning force of a vehicle by outputting a clutch hydraulic control signal and a brake hydraulic control signal to the control valve based on a deviation from the angular velocity. It is characterized in further comprising a stage.

According to the method and the apparatus for steering a tracked vehicle, the target turning angular velocity of the vehicle is set for a predetermined turning command value corresponding to, for example, the stroke value of the operating lever. A deviation from the detected actual turning angular velocity is calculated, and a clutch and a brake provided for each of the left and right driving wheels are controlled based on the deviation to control the turning force of the vehicle. In this way, a target turning angular velocity corresponding to the turning instruction value can be easily obtained only by setting a specific turning instruction value, and the vehicle can be automatically turned at this turning angular velocity. In the present invention, since the turning force of the vehicle is controlled based on a comparison operation between the actual turning angular velocity and the target turning angular velocity, it is not necessary to correct the influence of the crawler belt slip and to simplify the configuration. This has the effect that it can be performed.

In the steering apparatus for a tracked vehicle according to the present invention, the actual turning angular velocity detecting means may directly detect the angular velocity by a yaw rate gyro.
By using such a yaw rate gyro, the actual turning angular velocity of the vehicle can be directly detected, so that the device configuration is simplified.

The actual turning angular velocity detecting means may calculate the angular velocity by time-differentiating the azimuth detected by the azimuth sensor.

Further, the actual turning angular velocity detecting means includes a G
The angular velocity may be calculated by detecting the vehicle position by the position detection means using the PS. In the apparatus using the GPS position detecting means, two position detecting means are provided in the vehicle, and a vector between the two points is obtained from position information of two points on the vehicle detected by the two position detecting means. Thus, the azimuth and the angular velocity can be calculated from this vector. In another embodiment, the GPS
Is provided in the vehicle, two vectors are obtained from the position information at three time points detected at predetermined time intervals by the position detecting means, and the azimuth and angular velocity are calculated from these vectors. You can also. As described above, only by mounting the position detecting means by the GPS on the own vehicle, the position information of the own vehicle can be obtained with high accuracy without considering the correction of the crawler belt slip due to the soil condition or the load condition.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the method and the apparatus for steering a tracked vehicle according to the present invention will be described.
This will be described with reference to the drawings.

An embodiment applied to a bulldozer will be described below. FIG. 1 is an external view of a bulldozer according to one embodiment of the present invention.

In the bulldozer 1 of the present embodiment, a hood 3 and a driver's seat 4 are provided on a vehicle body 2.
A crawler belt 5 for advancing, retreating and turning the vehicle body 2 is provided on each of the left and right sides in the forward direction. These tracks 5
Is independently driven for each crawler belt 5 by the corresponding sprocket 6 by the driving force transmitted from the engine.

Left and right straight frames 8, 9 for supporting the blade 7 at the tip end are provided on the left and right sides of the vehicle body 2.
(The right trunnion is not shown) 10 is pivotally supported so that the blade 7 can move up and down. The blade 7 has a pair of left and right blade lift cylinders 11 for raising and lowering the blade 7 between the vehicle body 2 and the blade 7.
And a blade tilt cylinder 13 are provided by disposing the brace 12 between the left straight frame 8 and the blade tilt cylinder 13 between the right straight frame 9.

The steering lever 1 is located on the left side of the driver's seat 4.
5. Shift lever 16 and fuel control lever 17
The right side is provided with a blade control lever 18 and the like for raising, lowering, tilting left and right the blade 7. A dexel pedal (not shown) is provided in front of the driver's seat 4.

Next, in FIG. 2 showing the power transmission system, the rotational driving force from the engine 20 is applied to the damper 21.
And transmitted to the torque converter 23 through the PTO 22. Then, from the output shaft of the torque converter 23, the rotational driving force is transmitted to a transmission 24 that is, for example, a planetary gear wet multi-plate clutch transmission in which the input shaft is connected to the output shaft. The transmission 24 has a forward clutch, a reverse clutch, and first to third speed clutches, and its output shaft is rotated at three stages of forward and backward speeds. Next, the rotational driving force from the output shaft of the transmission 24 is transmitted to a pair of left and right final reduction gears 28 via a transfer 25 and left and right clutches 26 and brakes 27 for steering, and the sprockets 6 for running the crawler belt 5 are driven. Is driven.

In the present embodiment, a yaw rate gyro 29 as actual turning angular velocity detecting means is mounted on the vehicle body 2, and the yaw rate gyro 29 detects the turning angular velocity of the vehicle body 2. The output signal ω from the yaw rate gyro 29 is input to the controller 30 and used as information for calculating the turning force (steering force) of the vehicle. Note that this controller 3
0 is a lever stroke signal (turning command value signal) of the steering lever 15 as information for calculating the turning force.
S _{0 is} also input.

Next, a vehicle steering control procedure in this embodiment will be described with reference to a control system configuration diagram shown in FIG. 3 and a flowchart shown in FIG.

S1: As shown in FIG. 5, the soil condition
Turn command value S according to the load of the vehicle, etc.₀And target turn
Angular velocity ω₀In other words, the turning characteristic mode a,
are set in advance, and the turning characteristic mode
A desired characteristic mode is selected from a, b, c,. S2: A specific turning characteristic mode is operated by operating the steering lever 15.
Lever stroke of the steering lever 15
(Swing command value S₀Target turning angular velocity ω corresponding to) ₀Decide
Set.

S3: Input the actual turning angular velocity ω detected by the yaw rate gyro. S4: the target turning angular velocity ω ₀ obtained in step S2,
A deviation ω ′ from the actual turning angular velocity ω obtained in step S3 is obtained.

S5: The obtained deviation ω 'is multiplied by a predetermined gain k to obtain kω'. S6: omega from _{0 + kω} ', and outputs a clutch pressure signal P _C and the brake pressure signal P _B in accordance with the correlation characteristics between the target slewing angular velocity and the clutch and brake hydraulic pressure, shown in FIG.

[0023] Thus, the vehicle is operated in straight example the steering lever 15 in the rightward turning direction, the clutch pressure signal P _C and the brake pressure signal from the controller 30 in accordance with the target slewing angular velocity omega ₀ corresponding to the lever stroke P _B
Is output to the clutch control valve 31 and the brake control valve 32 on the right side, respectively, and the operating hydraulic pressure is sent to each of the right clutch 26 and the right brake 27 so that the actual turning angular speed ω matches the target turning angular speed ω ₀ , Right clutch 2
6 is released and the right brake 27 is braked. As a result, the rotation of the right sprocket 6 stops, the right crawler belt 5 stops, and the vehicle turns right (the same applies to the case of turning left). In addition,
When the steering lever 15 is returned to the neutral position, the right brake 2
7 is released and the right clutch 26 is engaged, so that the vehicle travels straight.

According to this embodiment, the vehicle can be automatically turned at the target turning angular velocity simply by operating the steering lever 15. In this case, since the turning force of the vehicle is controlled based on a comparison operation between the actual turning angular velocity ω and the target turning angular velocity ω ₀ , the control is performed in consideration of the crawler belt slip. It is not necessary to do it.

In this embodiment, the yaw rate gyro 29 for directly detecting the angular velocity of the vehicle is used as the actual turning angular velocity detecting means. The rotational angle velocity ω may be calculated by time-differentiating (dθ / dt) the azimuth angle θ detected by the azimuth sensor.

Further, the actual turning angular velocity detecting means includes a GP
S (Global Positioning System)
em) Position detection hand by real-time kinematic method
The step detects the vehicle position and calculates the angular velocity.
May be. In this case, the position detection means by GPS
2 pieces each, one each before and after
Position information X of two points on the vehicle detected₁(X₁,
y₁, Z₁) And X₂(X₂, Y₂, Z₂) From it
Vector X between two points₁X₂, And this vector X₁
X₂To calculate azimuth angle θ and turning angular velocity ω from
it can. In another aspect, the position based on the GPS
One detecting means is mounted on the vehicle, and this position detecting means
Position information X at time t₁(X₁, Y₁, Z₁),Time
Position information X at time t + Δt₂(X₂, Y₂, Z₂)
And position information X at time t + 2Δt₃(X₃, Y
₃, Z₃), And from these three location information, two
Kuturu X₁X₂And X₂X₃Find these vectors
Azimuth θ obtained from ₁₂And θ₂₃To next
It is also possible to calculate the turning angular velocity ω by the formula
You. ω = (θ₂₃−θ₁₂) / Δt

In the present embodiment, the turning command value is described as the lever stroke of the steering lever 15, but the turning command value may be the command turning angle of the automatic driving navigator.

Although the present embodiment has been described as applied to a bulldozer, it is needless to say that the present invention can be applied to other tracked vehicles.

[Brief description of the drawings]

FIG. 1 is an external view of a bulldozer according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a power transmission system.

FIG. 3 is a configuration diagram of a control system.

FIG. 4 is a flowchart illustrating a procedure of steering control;

FIG. 5 is a graph showing a turning characteristic mode.

FIG. 6 is a graph showing clutch / brake characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bulldozer 2 Body 5 Crawler belt 6 Sprocket 15 Steering lever 20 Engine 22 PTO 26 Clutch 27 Brake 29 Yaw rate gyro 30 Controller 31 Clutch control valve 32 Brake control valve

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Satoshi Morita 3-1-1 Ueno, Hirakata-shi, Osaka F-term in Komatsu Ltd. Osaka Plant (reference) 3D052 AA02 AA04 BB08 DD01 EE01 FF01 GG04 HH01 HH02 HH03 JJ03 JJ10 JJ11 JJ14 JJ17 JJ20 JJ22 JJ23 JJ31 JJ37

Claims (7)

[Claims] 1. A method for steering a tracked vehicle in which a clutch and a brake are provided on each of left and right drive wheels and the turning force of the vehicle is controlled by controlling the clutch and the brake. Using the relationship between the target turning angular velocity to the turning command value and the actual turning angular velocity of the detected vehicle,
A method for steering a tracked vehicle, wherein the clutch and the brake are controlled based on a deviation between the actual turning angular velocity and the target turning angular velocity. 2. A steering apparatus for a tracked vehicle comprising: a clutch and a brake on each of left and right drive wheels; and a control valve for controlling the clutch and the brake.
(A) target turning angular velocity setting means for setting a target turning angular velocity of the vehicle with respect to a predetermined turning command value; (b) actual turning angular velocity detecting means for detecting the actual turning angular velocity of the vehicle; and (c).
The actual turning angular velocity detected by the actual turning angular velocity detecting means is compared with a target turning angular velocity set by the target turning angular velocity setting means, and clutch hydraulic pressure control is performed based on the deviation between the actual turning angular velocity and the target turning angular velocity. A steering device for a tracked vehicle, comprising: a turning force control unit that outputs a signal and a brake hydraulic pressure control signal to the control valve to control a turning force of the vehicle. 3. The tracked vehicle steering apparatus according to claim 2, wherein the actual turning angular velocity detecting means directly detects the angular velocity by a yaw rate gyro. 4. The tracked vehicle steering apparatus according to claim 2, wherein the actual turning angular velocity detecting means calculates an angular velocity by time-differentiating an azimuth detected by an azimuth sensor. 5. The tracked vehicle steering apparatus according to claim 2, wherein the actual turning angular velocity detecting means detects the vehicle position by GPS position detecting means and calculates the angular velocity. 6. Two position detecting means by means of the GPS are provided, and a vector between the two points is obtained from position information of two points on the vehicle detected by the two position detecting means. The steering device for a tracked vehicle according to claim 5, wherein the azimuth and the angular velocity are calculated. 7. A position detecting means using GPS is provided, and two vectors are obtained from position information at three time points detected at predetermined time intervals by the position detecting means. The steering apparatus for a tracked vehicle according to claim 5, wherein the angular velocity is calculated.