JPH11322298A - Running speed controller for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a running speed controller, by which a vehicle can be turned in a stable condition, for an industrial vehicle. SOLUTION: A CPU inside a controller 20 controls a running motor 8 so as to set a vehicle speed complying with a manipulated variable Q of an accelerator pedal 7. A vehicle speed sensor 12 detects a speed Vn of a forklift, while a steering angle sensor 12 detects a steering angle θ, and a height sensor 16 and a load sensor 17 detect a height position (h) and a load weight (w) representing a condition related to stability of a cargo 100 carried on a vehicle. On the basis of the steering angle θ, the height position (h), and the load weight (w), the CPU computes a control speed Vc. Using the control speed Vc, the running motor 8 is controlled with respect to the vehicle speed Vn on demand, and speed reduction or speed restriction is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling speed control device for an industrial vehicle, and more particularly, to speed control during turning.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. 1-30105 discloses a traveling speed control device for turning an industrial vehicle.

[0003] As shown in FIG. 4, this traveling speed control device includes an accelerator sensor 3 in a battery forklift.
At 0, the depression angle Q of the accelerator pedal 31 is detected, and the controller 32 controls the current flowing to the traveling motor 33 according to the depression angle Q. By controlling the current flowing through the traveling motor 33, the number of revolutions of the drive wheel (front wheel) 34 is changed, and the vehicle speed is controlled according to the depression angle Q of the accelerator pedal 31.

On the other hand, the operation amount θ 'of the steering wheel 36 is detected by the rotation angle sensor 35, and the controller 32 controls the rear wheels 3 which are the steered wheels in accordance with the operation amount θ'.
By controlling the steering angle of the vehicle 7, the vehicle (machine base) can be turned. Further, the controller 32 includes a rotation sensor 38
When the number of rotations of the drive wheel 34 detected by the controller becomes equal to or more than the number of rotations required for deceleration determined according to the operation amount θ ′ of the steering wheel 36, the number of rotations of the traveling motor 33 is reduced to a predetermined value. By limiting the traveling speed in this way, stability during turning traveling of the battery forklift is achieved.

[0005]

However, in recent years, further improvements have been made in order to ensure stable running performance when turning, by improving the running performance of industrial vehicles and the performance of cargo handling equipment, and standardizing the power steering. It has been demanded. That is,
In the traveling speed control device shown in FIG. 4, the stabilization at the time of turning is attempted based on the operation amount θ 'of the steering wheel 36 and the rotation speed of the drive wheel (front wheel) 34. Further improvements are desired.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a traveling speed control device for an industrial vehicle which can further improve its performance and can make cornering in a more stable state.

[0007]

According to a first aspect of the present invention, there is provided a travel driving unit for traveling a vehicle, and the traveling drive unit is controlled to achieve a vehicle speed corresponding to an operation amount of an operation member. First traveling speed control means, turning state detection means for detecting a steering angle or a yaw rate acting on the vehicle,
A cargo condition detection means for detecting a stability condition of the cargo material mounted on the vehicle, and a steering angle or a yaw rate by the turning condition detection device and a condition related to the stability of the cargo material by the cargo condition detection device. A second traveling speed control means for decelerating or regulating the speed of the vehicle by the first traveling speed control means when necessary.

According to the first aspect of the present invention, the first drive speed control means controls the travel drive means so as to set the vehicle speed in accordance with the operation amount of the operation member. Further, the steering angle or the yaw rate acting on the vehicle is detected by the turning state detecting means. Further, a state relating to the stability of the cargo carried on the vehicle is detected by the cargo condition detection means. Then, the second traveling speed control means performs deceleration or speed regulation on the vehicle speed as necessary based on the steering angle or the yaw rate and the state relating to the stability of the cargo. As a result, the cornering can be performed in a stable state.

According to a second aspect of the present invention, in the traveling speed control apparatus for an industrial vehicle according to the first aspect, the cargo condition detection means is provided on the vehicle so as to be able to move up and down to hold the cargo. Lifting position detecting means for detecting a lifting position of the cargo handling member, and load detecting means for detecting a load acting on the cargo handling member.

According to the second aspect of the present invention, the first aspect is provided.
In addition to the operation of the invention described in (1), the lifting position detecting means detects the lifting position of the cargo handling member for holding the cargo, and the load detecting means detects the load acting on the cargo handling member.

According to a third aspect of the present invention, in the traveling speed control apparatus for an industrial vehicle according to the second aspect, the second traveling speed control means includes a steering angle or a yaw rate by the turning state detection means, The control speed during turning is calculated based on the lifting position of the cargo handling member by the high position detecting means and the load acting on the cargo handling member by the load detecting means, and the deceleration or speed is calculated based on the vehicle speed and the control speed. Regulations are to be implemented.

According to the invention described in claim 3, according to claim 2,
In addition to the operation of the invention described in the above, the second traveling speed control means controls the steering angle or the yaw rate by the turning state detecting means, the lifting position of the cargo handling member by the lifting position detecting means, and the load detecting means. A control speed during turning is calculated based on the load acting on the cargo handling member, and deceleration or speed regulation is performed based on the vehicle speed and the control speed.

According to a fourth aspect of the present invention, in the traveling speed control apparatus for an industrial vehicle according to the third aspect, the second traveling speed control means compares the control speed with the vehicle speed to make a turn. If the vehicle speed exceeds the control speed while driving,
The vehicle speed is to be reduced.

According to the invention described in claim 4, according to claim 3,
In addition to the operation of the invention described in the above, the control speed and the vehicle speed are compared by the second running speed control means, and if the vehicle speed exceeds the control speed during turning traveling, the vehicle speed is reduced.

According to a fifth aspect of the present invention, in the traveling speed control device for an industrial vehicle according to the third aspect, the second traveling speed control means is provided when the acceleration control is performed during the turning traveling. Speed control is performed so that the vehicle speed does not exceed the control speed.

According to the invention described in claim 5, according to claim 3,
In addition to the operation of the invention described in the above, the vehicle speed is regulated by the second traveling speed control means so as not to exceed the control speed when the acceleration control is performed during the turning travel.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a battery forklift will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of a traveling speed control device in a forklift according to the present embodiment. This forklift has four wheels, front wheels 1 and 2 are driving wheels, and rear wheels 3 and 4 are steering wheels. The forklift is provided with a fork 5, and the fork 5 is used to
0 can be lifted and transported.

More specifically, an accelerator sensor 6 detects a depression angle (operation amount) Q of an accelerator pedal 7 as an operation member, and based on the pedal depression amount Q, a driving wheel (front wheel).
1 and 2 are rotationally driven by a traveling motor 8 as traveling driving means. The rotating shaft 9 of the driving wheels 1 and 2 is provided with a vehicle speed sensor 10 for detecting the number of rotations (vehicle speed Vn) of the driving wheels 1 and 2.

The steered wheels (rear wheels) 3 and 4 are steered by a steering mechanism (not shown) by an amount corresponding to the operation amount of the steering wheel 11, and the vehicle (machine stand) turns. The steering wheels 3 and 4 are provided with a steering angle sensor 12 for detecting the steering angle θ of the steering wheels 3 and 4.

The forklift is provided with a pair of left and right outer masts 13 at the front thereof, and an inner mast 14 is arranged between the outer masts 13 so as to be able to move up and down. A fork 5 as a cargo handling member is disposed on the inner mast 14,
Lift cylinder 1 arranged on the back of outer mast 13
5 moves the fork 5 up and down. Then, the cargo 100 is placed on the fork 5 and is operated at a desired lifting position h, and can be held at the lifting position h.

The outer mast 13 is provided with a lift sensor 16 for detecting the lift position h of the fork 5. The lift cylinder 15 is provided with a load sensor 17 for detecting a load w of the cargo 100 on the fork 5. That is, the load acting on the fork 5 can be detected by the load sensor 17. Therefore, the state relating to the stability of the cargo load 100 mounted on the forklift can be detected by the lift sensor 16 and the load sensor 17. As described above, in the present embodiment, the lifting sensor 16 and the load sensor 17 constitute a cargo-loading state detection unit.

Next, the electrical configuration of the traveling speed control device will be described with reference to FIG. As shown in FIG. 2, the traveling speed control device includes a controller 20. In the present embodiment, the controller 20 is a central processing unit (CPU) 2
1. Read-only memory (RO) storing control program
M) 22, readable and writable memory (RAM) 23 for temporarily storing data, input interface 2
4, an output interface 25, and a drive circuit 26 for driving the traveling motor 8.

The CPU 21 has the above-mentioned accelerator sensor 6,
Each detection signal from the vehicle speed sensor 10, the steering angle sensor 12, the lift sensor 16 and the load sensor 17 is input via the input interface 24. Then, the CPU 21 receives the input signal, the depression angle Q of the accelerator pedal 7, the vehicle speed Vn, the steering angle θ of the steered wheels 3, and the lift position h of the fork 5.
And the load w of the cargo 100 is detected. Also, CPU
21 is a drive circuit 26 via an output interface 25
To output an on / off signal to control the rotation speed of the traveling motor 8.

Next, the operation of the traveling speed control device will be described.
This will be described with reference to FIG. FIG. 3 is a flowchart showing the processing executed by the CPU 21. First, in step 100, the CPU 21 captures the depression angle (operation amount) Q of the accelerator pedal 7, and proceeds to step 101 to determine the lifting position h of the fork 5 and the load w of the cargo 100 on the fork 5. Take in. Then, the CPU 21 calculates the lateral G at which the vehicle can travel safely using the control data stored in the ROM 22 in advance for the lift position h and the load w. Here, the lateral G is an acceleration applied to the vehicle (machine base) in the lateral direction during the turning traveling.
Further, the CPU 21 proceeds to step 102 to take in the steering angle θ, and using this steering angle θ, the distance from the center point OR of the forklift when turning to the center point O of the vehicle body of the forklift as shown in FIG. (Rotation radius) R is calculated, and the yaw rate (rotational angular velocity around a vertical axis passing through the center of gravity O of the machine) ω is calculated based on the change in the steering angle θ. Thereafter, in step 103 of FIG. 3, the CPU 21 calculates the control speed Vc using the calculated data G, R, and ω as in the following equation.

Vc = MIN (√ (GR), G / ω) That is, the speed calculated by √ (GR) and G /
The slower one of the speeds calculated by ω is defined as the control speed Vc.

Further, the CPU 21 fetches the current traveling speed Vn of the forklift based on the detection signal of the vehicle speed sensor 10 in step 104, and compares the actual traveling speed Vn with the calculated control speed Vc in step 105. I do. When the traveling speed Vn is lower than the control speed Vc in step 105 (Vc> Vn), the CPU 2
1 proceeds to step 106 to set the normal traveling mode. In this mode, the CPU 21 controls the vehicle speed Vn so that the vehicle speed corresponds to the depression amount Q of the accelerator sensor 6. That is, the CPU 21 sets a duty ratio so as to obtain a vehicle speed corresponding to the pedal depression angle Q, and outputs an on / off signal to the traveling motor 8 via the drive circuit 26 at this duty ratio to flow to the traveling motor 8. Control the current. Then, the speed of the forklift is controlled by changing the number of revolutions of the traveling motor 8 by this current.

In step 105, when the traveling speed Vn is compared with the control speed Vc and it is determined that the traveling speed is high (Vc <Vn), the CPU 21 proceeds to step 107 and sets the forced traveling mode (I). In this mode, the CPU 21 controls an output signal to the traveling motor 8 so as to decelerate. That is, the rotational speed of the traveling motor 8 is reduced to reduce the traveling speed Vn. And step 1
At 05, if Vc = Vn, the CPU 21 proceeds to step 108 to set the forced traveling mode (II). In this mode, the CPU 21 controls an output signal to the traveling motor 8 via the drive circuit 26 so as not to accelerate. That is, the rotation speed of the traveling motor 8 is controlled so that the traveling speed Vn is kept constant at the control speed Vc, thereby regulating the traveling speed Vn.

In this way, when the vehicle is turning at a speed lower than the control speed Vc, that is, when the vehicle is traveling in the normal traveling mode, the driver (operator) steps on the accelerator pedal 7; That is, in the case where the acceleration operation is performed, the CPU 21 accelerates according to the depression angle Q of the accelerator pedal 7, and shifts to the forced traveling mode (II) when the traveling speed Vn becomes equal to the control speed Vc. Acceleration beyond the control speed Vc is restricted. That is, the control speed Vc becomes the regulation speed.

In the present embodiment, the lateral G that can travel in a stable state is calculated based on the lifting position h of the fork 5 and the load w of the cargo 100 on the fork 5, and the steering angle sensor 12 The turning radius R of the forklift is calculated on the basis of the steering angle θ detected by the steering wheel, and the speed (√ (G · R)) calculated by the radius R and the lateral G;
Yaw rate ω of forklift based on change in steering angle θ
The smaller one of the speeds (G / ω) calculated by the horizontal G and the lateral G is set as the control speed Vc. Thus, for example, when the steering wheel 11 is switched from right turning to left turning, when the steering angle θ of the steered wheels 3 and 4 by the steering wheel 11 indicates the straight traveling direction (θ = 0 °) (R = ∞,
That is, also in (√ (GR) = ∞), the yaw rate ω applied to the forklift is calculated by monitoring the change in the steering angle θ. The control speed Vc is determined based on the yaw rate ω and the lateral G that allows the vehicle to travel in a stable state.
Since (G / ω) is calculated, it is practically preferable.

The present embodiment does not detect the operation amount of the steering wheel 36 for instructing the steering angle as in the traveling speed control device shown in FIG. Since the actual steering angle θ of the machine base is detected by the steering angle sensor 12 provided in the vehicle, the error in the detected steering angle θ is reduced, and the traveling speed control during turning can be performed more accurately. It has become.

As described above, the present embodiment has the following features. (1) The CPU 21 as the first traveling speed control unit and the second traveling speed control unit determines the steering angle θ of the forklift and the stability (fork 5
Vehicle speed Vn corresponding to the depression angle Q of the accelerator pedal 7 based on the lifting position h of the vehicle and the load w) of the cargo load 100.
On the other hand, if necessary in the process of step 105 in FIG. 3, deceleration in step 107 or speed regulation in step 108 is performed. As a result, the forklift can perform the turning traveling in a stable state. (2) The CPU 21 determines the steering angle θ and the lift position h of the fork 5
The control speed Vc during turning is calculated based on the load w of the cargo 100 and the vehicle speed Vn and the control speed Vc, so that deceleration or speed regulation is performed, which is practically preferable. That is, the traveling speed Vn of the forklift is accurately controlled, and the forklift can perform the turning traveling in a more stable state. (3) The CPU 21 compares the control speed Vc with the vehicle speed Vn, and if the running speed Vn exceeds the control speed Vc,
Since the deceleration control is performed, this is practically preferable. In other words, when the control speed Vc calculated by performing the turning operation during traveling in the normal traveling mode in step 106 decreases, and when the current traveling speed Vn of the forklift exceeds the control speed Vc, the CPU 21 proceeds to step 107. Then, the traveling speed Vn of the forklift is reduced. Therefore, even if the turning operation is performed and the current traveling speed Vn of the forklift becomes faster than the control speed Vc at which the vehicle can travel safely,
Since the CPU 21 reduces the rotation speed of the traveling motor 8 to reduce the traveling speed Vn of the forklift, the turning traveling can be performed in a stable state. (4) When the accelerator pedal 7 is depressed during turning and acceleration control is performed, the CPU 21 determines the vehicle speed Vn.
Is controlled so as not to exceed the control speed Vc, which is practically preferable. In other words, even if the driver depresses the accelerator pedal 7 during the cornering operation and performs an acceleration operation, when the traveling speed Vn of the forklift becomes equal to the control speed Vc, the process shifts to the forced traveling mode (II) in step 108. Then, the rotation speed of the traveling motor 8 is controlled so that the traveling speed does not exceed the control speed Vc, and the traveling speed Vn of the forklift is regulated, so that the turning traveling can be performed in a stable state.

The embodiment of the present invention is not limited to the above embodiment, but may be implemented as follows. In the above embodiment, the steering angle sensor 12 is used as the turning state detecting means. However, a yaw rate sensor that detects the yaw rate acting on the vehicle may be used as the turning state detecting means. That is, in the above embodiment, the steered wheels 3, 4
The yaw rate ω applied to the forklift is calculated based on a change in the steering angle θ by detecting the steering angle θ by the steering angle sensor 12 attached to the vehicle. A new yaw rate sensor 18 is provided as shown by a broken line in FIG. Alternatively, the yaw rate sensor 18 may detect the yaw rate ω applied to the forklift. Yaw rate sensor 18
Is used, the yaw rate ω actually applied to the forklift is detected, and based on the yaw rate ω and the lateral G that can travel in a stable state, the more accurate control speed Vc (G /
ω) can be calculated, which is practically preferable. Further, if the yaw rate sensor 18 is used, the yaw rate ω actually applied to the forklift can be detected instead of predicting (calculating) the yaw rate ω applied to the forklift as in the above-described embodiment. By monitoring, an accurate control speed Vc (G /
ω) can be calculated.

In the above embodiment, the steering angle sensor 12 as the turning state detecting means is attached to the steered wheels 3.
Instead of the steering angle sensor 12, the steering wheel 1
The steering angle θ may be detected using a detector (for example, a rotation angle sensor) that detects the first operation amount.

In the above-described embodiment, the lift sensor 16 and the load sensor 17 are used as the cargo state detection means. However, the present invention is not limited to this, and only the lift sensor 16 or the load sensor 17 may be used.

In the above embodiment, the present invention is embodied as a battery forklift, and the electric traveling motor 8 is used as traveling driving means.
However, the present invention may be embodied using a hydraulic motor or an engine.

[0037]

As described in detail above, according to the first aspect of the present invention, it is possible to perform a turning operation in a more stable state.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in (1), it is possible to detect a state related to the stability of the cargo carried on the vehicle, which is practically preferable.

According to the invention set forth in claim 3, according to claim 2
In addition to the effects of the invention described in the above, the second traveling speed control means can accurately perform deceleration or speed regulation based on the vehicle speed and the control speed, which is practically preferable.

According to the invention described in claim 4, according to claim 3,
In addition to the effects of the invention described in the above, even if the turning operation is performed and the current speed of the vehicle is higher than the control speed at which the vehicle can safely travel, the speed of the vehicle is reduced by the second traveling speed control means, The turning traveling can be performed in a stable state.

According to the invention described in claim 5, according to claim 3,
In addition to the effects of the invention described in (1), since the speed is regulated by the second traveling speed control means so as not to exceed the control speed, the turning traveling can be performed in a stable state.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a traveling speed control device of a forklift according to an embodiment.

FIG. 2 is a block diagram showing an electrical configuration of the traveling speed control device.

FIG. 3 is a flowchart for explaining the operation of the embodiment;

FIG. 4 is a configuration diagram of a traveling speed control device in a conventional forklift.

[Explanation of symbols]

5 fork, 7 accelerator pedal, 10 vehicle speed sensor, 12 steering angle sensor, 16 height sensor, 17 load sensor, 18 yaw rate sensor, 21 CPU.

Claims (5)

[Claims] 1. A traveling drive means for traveling a vehicle, a first traveling speed control means for controlling the traveling drive means to achieve a vehicle speed corresponding to an operation amount of an operation member, a steering angle or a vehicle. Turning state detecting means for detecting a yaw rate acting on the vehicle; cargo state detecting means for detecting a state relating to the stability of a cargo object mounted on a vehicle; a steering angle or a yaw rate by the turning state detecting means; A traveling speed of an industrial vehicle, comprising: a second traveling speed control unit that decelerates or regulates the vehicle speed by the first traveling speed control unit when necessary based on a state regarding stability of the cargo by the detection unit. Control device. 2. The cargo handling state detecting means, which is provided on the vehicle so as to be able to ascend and descend, detects a lifting position of a cargo handling member for holding a cargo, and acts on the cargo handling member. 2. A load detecting means for detecting a load.
3. The traveling speed control device for an industrial vehicle according to claim 1. 3. The second traveling speed control means acts on a steering angle or a yaw rate by the turning state detection means, a lifting position of the loading member by the lifting position detection means, and a loading member by the load detection means. The travel speed control device for an industrial vehicle according to claim 2, wherein the control speed at the time of turning traveling is calculated based on the load, and deceleration or speed regulation is performed based on the vehicle speed and the control speed. 4. The second travel speed control means compares the control speed with the vehicle speed, and reduces the vehicle speed if the vehicle speed exceeds the control speed during turning. The traveling speed control device for an industrial vehicle according to claim 3. 5. The vehicle according to claim 3, wherein said second traveling speed control means regulates a speed so that a vehicle speed does not exceed said control speed when acceleration control is performed during turning. The travel speed control device for an industrial vehicle according to claim 1.