JP4924584B2 - Pitching suppression device for industrial vehicles - Google Patents

Description

  The present invention relates to a pitching suppression device that suppresses pitching, which is a motion caused by a moment about a left-right axis with respect to a traveling direction of an industrial vehicle, that is, a motion that rotates up and down about a left-right axis.

In Patent Document 1, for pitching suppression in a train, pitching of a specific frequency component is detected, and traveling motor torque is compensated by that component to suppress pitching. In Patent Document 2, pitching is detected from fluctuations in vehicle speed in a forklift, and a speed command to a traveling motor is fixed when the forklift is in a pitching state.
JP 2006-238513 A Japanese Patent Laid-Open No. 2004-129459

  Since a forklift does not have a suspension like a passenger car, pitching cannot be suppressed by setting springs and dampers when traveling on rough roads. Forklift pitching is mainly caused by tire deflection, and its frequency changes depending on the balance between the load and the counterweight.

  In Patent Document 1, since the pitching detection frequency is fixed, when the pitching frequency changes greatly depending on the state of the load, such as a counterbalance forklift, there is a possibility that it cannot be compensated. In Patent Document 2, since the speed command to the traveling motor is fixed when in the pitching state, even if the accelerator is returned during pitching, deceleration cannot be started until the pitching state ends.

  The present invention has been made under such a background, and an object of the present invention is to pitch industrial vehicles capable of suppressing pitching regardless of the state of the load and ensuring responsiveness to accelerator operation. It is to provide a suppression device.

  According to the first aspect of the present invention, the driving wheel is driven by a traveling motor mounted on the vehicle body, a cargo handling device is provided for loading a load at the front portion of the vehicle body, and a counterweight is provided at the rear portion of the vehicle body. A pitching suppression device for an industrial vehicle, which outputs a signal according to a traveling motor control means for controlling the traveling motor in accordance with an operation amount of an accelerator operating member, and an output shaft of the traveling motor or a rotational speed of the driving wheel. The rotation speed detection means for estimating the pitching frequency based on the weight of the load, and the pitching frequency estimation means in the signal corresponding to the rotation speed from the rotation speed detection means. The pitching frequency component is extracted, and the traveling motor is controlled to reduce the size of the pitching frequency component. And summarized in that comprising a pitching suppressing means.

  According to the first aspect of the present invention, the travel motor is controlled by the travel motor control means in accordance with the operation amount of the accelerator operation member. Further, a signal corresponding to the rotational speed of the output shaft of the traveling motor or the driving wheel is output from the rotational speed detecting means. Further, the pitching frequency is estimated based on the weight of the load by the pitching frequency estimating means. The pitching suppression means extracts the pitching frequency component estimated by the pitching frequency estimation means in the signal corresponding to the rotation speed from the rotation speed detection means, and travels so as to reduce the size of the pitching frequency component. The motor is controlled. Thereby, pitching is suppressed regardless of the state of the load. Further, even if the accelerator operating member is operated in the pitching state, the traveling motor is controlled by the traveling motor control means, and responsiveness to the accelerator operation is ensured.

  The pitching suppression device for an industrial vehicle according to claim 1, wherein the pitching frequency estimation means is configured to determine the pitching frequency based on the weight of the load and at least the height position of the load. , It is possible to suppress the pitching regardless of the state of the load.

  The pitching suppression device for an industrial vehicle according to claim 1 or 2, wherein the pitching frequency estimation means is based on a weight of the load and at least a tilt angle of the cargo handling device. If the pitching frequency is estimated, the pitching can be further suppressed regardless of the state of the load.

  The pitching suppression device for an industrial vehicle according to any one of claims 1 to 3, wherein a signal corresponding to an operation amount of the accelerator operation member is transmitted through the low-pass filter to the traveling motor. When the cut-off frequency is changed by the pitching frequency estimated by the pitching frequency estimation means, the low-pass filter sent to the control means can prevent an increase in vibration due to accelerator shake caused by body vibration due to pitching.

  6. The industrial vehicle pitching suppression device according to claim 1, wherein a signal corresponding to an operation amount of the accelerator operation member is transmitted through the low-pass filter to the traveling motor. The low-pass filter sent to the control means can prevent deterioration of the follow-up performance to the operation of the accelerator operating member when the attenuation slope is changed by the magnitude of the pitching frequency component by the pitching suppression means.

  According to the present invention, pitching can be suppressed regardless of the state of the load, and responsiveness to the accelerator operation can be ensured.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
In FIG. 1, the schematic side view of the forklift as an industrial vehicle in this embodiment is shown. FIG. 2 shows a block diagram of a control system for the travel motor including the pitching suppression device.

  As shown in FIG. 1, the forklift 1 is a battery forklift that is driven by an electric motor. A drive wheel (front wheel) 3 a is provided at the front lower portion of the vehicle body 2 of the battery forklift 1, and a steering wheel (rear wheel) 3 b is provided at the rear lower portion of the vehicle body 2. A cargo handling device 4 is provided at the front of the vehicle body 2.

  A mast 5 constituting the cargo handling device 4 is erected on the front portion of the vehicle body 2. The mast 5 includes a pair of left and right outer masts 5a supported so as to be tiltable back and forth with respect to the vehicle body 2, and an inner mast 5b that slides up and down. A lift cylinder 6 is disposed at the rear of each outer mast 5a. A lift bracket 8 having a fork 7 is supported inside the inner mast 5b so as to be movable up and down. Then, the fork 7 is lifted and lowered together with the lift bracket 8 by the expansion and contraction operation of the lift cylinder 6. Then, the load 18 can be mounted on the fork 7 constituting the cargo handling device at the front portion of the vehicle body 2 so as to be movable up and down.

  The pair of left and right tilt cylinders 9 is pivotally connected to the vehicle body (body frame) 2 at the base end side, and is pivotally connected to the side surface of the outer mast 5a at the distal end side. The mast 5 tilts back and forth as the tilt cylinder 9 is driven to expand and contract.

  The cab S is equipped with a handle 10, a lift lever 11 and a tilt lever 12 on the front side thereof. The lift lever 11 is a lever for raising and lowering the fork 7, and the tilt lever 12 is a lever for tilting the mast 5 in the front-rear direction. An accelerator pedal 13 is provided on the floor of the driver's seat, and the vehicle speed is set according to the amount of operation of the accelerator pedal 13 (the amount of pedal depression).

  A battery 14 and a travel motor 15 are mounted on the vehicle body 2. The traveling motor 15 is driven by the battery 14 so that the driving wheel 3a is driven. Specifically, the output shaft of the travel motor 15 is connected to the rotation shaft of the drive wheel 3a via a speed reducer. When the output shaft is rotated by the drive of the travel motor 15, the rotation shaft of the drive wheel 3a is rotated along with the rotation. The drive wheel 3a is driven by rotation.

  Also, a cargo handling motor (not shown) is driven by the battery 14, and a hydraulic pump (not shown) is driven by the driving of the cargo handling motor. Based on the driving of the hydraulic pump, the lift cylinder 6 and the tilt cylinder 9 can be expanded and contracted so that the fork 7 can be moved up and down and tilted. On the other hand, a counterweight 16 is provided at the rear part of the vehicle body 2.

  In FIG. 2, an accelerator opening sensor 23 is provided in the forklift 1. The accelerator opening sensor 23 detects an operation amount of the accelerator pedal 13, that is, an accelerator opening α. A motor control unit 26 is connected to the accelerator opening sensor 23, and the motor control unit 26 detects an operation amount of the accelerator pedal 13 based on a signal from the accelerator opening sensor 23. The motor control unit 26 adjusts the torque of the traveling motor 15 to drive the drive wheels 3 a mechanically connected to the traveling motor 15. At this time, the motor control unit 26 inputs (feeds back) a motor rotation number detection signal from the motor rotation number sensor 27, and the motor control unit 26 controls the traveling motor 15 so that the vehicle speed is in accordance with the accelerator opening. To do. That is, the motor control unit 26 serving as a travel motor control unit controls the travel motor 15 to achieve a travel speed corresponding to the operation amount of the accelerator pedal 13 serving as an accelerator operation member.

  A vehicle speed sensor may be used instead of the motor rotation speed sensor 27. That is, since the output shaft of the travel motor 15 and the rotation shaft of the drive wheel 3a are connected via a speed reducer, instead of detecting the rotational speed of the output shaft of the travel motor 15 by the motor rotation speed sensor 27, the drive wheel is driven. The rotational speed (vehicle speed) 3a may be detected.

  Further, the forklift 1 includes a lift height sensor 20, a load sensor 21, and a tilt angle sensor 22. The lift height sensor 20 detects the lift height H of the fork 7, that is, the height position of the load 18. The load sensor 21 detects the weight (load F) of the load 18. Specifically, the weight (load F) of the load 18 is detected by detecting the hydraulic pressure in the bottom chamber of the lift cylinder 6. The tilt angle sensor 22 detects the tilt angle of the mast 5 constituting the cargo handling device, that is, the tilt angle θ. Specifically, the tilt angle θ is detected by detecting the rotation angle of the tilt cylinder 9 relative to the vehicle body 2.

  A pitching frequency estimation unit 24 is connected to the elevation sensor 20, the load sensor 21, and the tilt angle sensor 22. The pitching frequency estimation unit 24 detects the lift height H (the height position of the load 18) of the fork 7 from the signal from the lift sensor 20, and the load F (the weight of the load 18) from the signal from the load sensor 21. Further, the tilt angle θ is detected by a signal from the tilt angle sensor 22. The pitching frequency estimation unit 24 estimates the pitching frequency fp.

  A pitching detection unit 25 is connected to the pitching frequency estimation unit 24, and the pitching frequency fp estimated by the pitching frequency estimation unit 24 is sent to the pitching detection unit 25. Further, a motor rotation number sensor 27 is connected to the pitching detection unit 25, and an output signal (motor rotation number detection signal) of the motor rotation number sensor 27 is input. The pitching detection unit 25 detects the strength (magnitude) Gp of the component of the pitching frequency fp estimated by the pitching frequency estimation unit 24 in the motor rotation number detection signal.

  A motor control unit 26 is connected to the pitching detection unit 25. The motor control unit 26 controls the torque of the traveling motor 15 to reduce the Gp value (control of the energization current of the motor, etc.) and suppresses pitching.

Next, the operation of the forklift pitching suppression device will be described.
When the occupant operates the accelerator pedal 13, the operation amount, that is, the accelerator opening α is detected by the accelerator opening sensor 23. An accelerator opening degree detection signal is sent from the accelerator opening degree sensor 23 to the motor control unit 26 as a required vehicle speed. The motor control unit 26 controls the traveling motor 15 based on the accelerator opening detection signal from the accelerator opening sensor 23. Further, the motor control unit 26 receives the motor rotation number detection signal from the motor rotation number sensor 27, and controls the traveling motor 15 so that the required vehicle speed corresponding to the accelerator opening is obtained (so that the required vehicle speed is obtained). To control the torque of the traveling motor 15).

  On the other hand, the pitching frequency estimation unit 24 estimates the pitching frequency fp from the state of the load 18 (lifting height H, load F, tilt angle θ) obtained by the sensors 20, 21, and 22 using an arithmetic expression obtained in advance. To do. Specifically, for the lift height H, when the lift height H is large, the pitching frequency fp is set low. As for the load F, when the load F is large, the pitching frequency fp is set low. Further, with respect to the tilt angle θ, the pitching frequency fp is set high when the tilt angle θ is large and the distance to the center of gravity is small, and the pitching frequency fp is set low when the tilt angle θ is large and the distance to the center of gravity is large. Is done. Specifically, the estimated pitching frequency is, for example, several Hz.

Thereby, the pitching frequency to be detected can be made variable, and the pitching frequency according to the state of the load 18 (lifting height H, load F, tilt angle θ) can be determined.
Although the pitching frequency was estimated from the three elements of lift height H, load F, and tilt angle (tilt angle θ), the three elements of lift height H, load F, and tilt angle are not necessarily required. For example, the load F alone can be used as an element, the load F and the lift height H can be used as elements, and the load F and the tilt angle can be used as elements.

  The pitching detection unit 25 extracts a component at the estimated pitching frequency fp shown in FIG. 4 in the rotation speed detection signal shown in FIG. 3 by the motor rotation number sensor 27 and calculates its strength (magnitude) Gp. That is, only a predetermined frequency component is extracted from the rotation speed signal by filtering, and the magnitude of the frequency component is calculated. Specifically, a component centered on the estimated pitching frequency fp is extracted (cut out) and its size is calculated.

  The motor control unit 26 adjusts the torque of the traveling motor 15 with a signal from the pitching detection unit 25 and suppresses pitching. That is, the torque of the traveling motor 15 is adjusted so that the strength (magnitude) Gp of the component at the estimated pitching frequency fp becomes zero.

  Further, when the accelerator pedal 13 is operated in the pitching state, the motor control unit 26 controls the traveling motor 15 so as to achieve a traveling speed corresponding to the accelerator operation amount by a signal from the accelerator opening sensor 23. Therefore, even if the accelerator pedal 13 is operated in the pitching state, the motor control unit 26 controls the traveling motor 15 and ensures responsiveness to the accelerator operation.

According to the above embodiment, the following effects can be obtained.
(1) The forklift pitching suppression device includes a motor control unit 26, a motor rotation number sensor 27 as a rotation speed detection means, a pitching frequency estimation unit 24, and a pitching detection unit 25. A signal corresponding to the rotational speed of the output shaft (or drive wheel 3a) of the travel motor 15 is output. A motor control unit 26 serving as a travel motor control unit controls the travel motor 15 so as to achieve a travel speed corresponding to the operation amount of the accelerator pedal 13. On the other hand, the pitching frequency estimation unit 24 as a pitching frequency estimation unit estimates the pitching frequency fp based on the weight (load F) of the load 18 detected by the load sensor 21, and the pitching detection unit 25 as a pitching suppression unit. And the motor control part 26 extracts the estimated pitching frequency component in the signal according to the rotational speed from the motor rotation speed sensor 27, and controls the traveling motor 15 so that the magnitude | size of the said pitching frequency component may be made small. Therefore, pitching can be suppressed regardless of the state of the load 18 and responsiveness to the accelerator operation can be ensured.

  (2) Since the pitching frequency estimation unit 24 estimates the pitching frequency fp based on the weight of the load 18 and at least the height position of the load 18, the pitching frequency estimation unit 24 can further suppress the pitching regardless of the state of the load. .

  (3) Since the pitching frequency estimation unit 24 estimates the pitching frequency fp based on the weight of the load 18 and at least the tilt angle, that is, the tilt angle of the mast 5 constituting the cargo handling device 4, the pitching frequency estimation unit 24 becomes more loaded. Therefore, pitching can be suppressed.

In addition, you may change this embodiment as follows.
As shown in FIG. 5, the output signal of the accelerator opening sensor 23 (a signal corresponding to the operation amount of the accelerator operation member) is sent to the motor control unit 26 via the low-pass filter 30. As shown in FIG. 6, the low-pass filter 30 has a variable cutoff frequency fc and a variable attenuation slope. In the low-pass filter 30, the cutoff frequency fc is changed by the pitching frequency fp estimated by the pitching frequency estimation unit 24. That is, the estimated pitching frequency fp is set to the cutoff frequency fc of the low-pass filter 30 or the vicinity thereof. Thereby, only the frequency component below the pitching frequency fp becomes the required vehicle speed, and it is possible to prevent an increase in vibration due to the accelerator shake due to the body vibration due to the pitching. That is, it is possible to prevent the vibration caused by pitching from being transmitted to the driver and the accelerator pedal 13 to move and further aggravate the vibration.

  Further, the attenuation slope of the low-pass filter 30 is changed by the strength (magnitude) Gp of the pitching frequency component by the pitching detection unit 25. Specifically, since there is little possibility of pitching when traveling on a flat road, it is not necessary to apply the low pass filter 30. Therefore, when the magnitude of the pitching frequency component (intensity Gp) is small, the deterioration of the ability to follow the operation of the accelerator pedal 13 can be prevented by reducing the attenuation gradient and weakening the effectiveness of the filter 30. it can.

  As described above, by performing an appropriate filter process corresponding to the pitching frequency fp and the like on the accelerator input, it is possible to reduce the influence of the vehicle vibration on the accelerator without deteriorating the vehicle response to the accelerator.

-Although the accelerator pedal 13 was used as an accelerator operation member, it is not restricted to this, For example, a lever etc. may be used.
-It may be applied to a hybrid forklift, that is, a forklift equipped with an engine and a traveling motor 15, and in short, is applied to a counterbalanced industrial vehicle that travels by driving a drive wheel by the rotational force of an electric motor. be able to.

  -Although the structure which controls the driving | running | working motor 15 in order to make it the driving speed according to the operation amount of the accelerator pedal 13 was employ | adopted, it is not restricted to this, For example, it drive | works so that it may become a motor output according to the operation amount of the accelerator pedal 13. You may employ | adopt the structure which controls a motor. In short, the travel motor control means only needs to control the travel motor in accordance with the operation amount of the accelerator operation member.

The schematic side view of the forklift in this embodiment. The block diagram of the control system of the traveling motor including a pitching suppression apparatus. The wave form diagram which shows the output of a motor rotation speed sensor. The figure which shows the intensity | strength with respect to the frequency in the output waveform of a motor rotation speed sensor. The circuit diagram of the control system of the traveling motor in another example. FIG.

Explanation of symbols

  2 ... Vehicle body, 3a ... Driving wheel, 5 ... Mast, 7 ... Fork, 13 ... Accelerator pedal, 15 ... Traveling motor, 16 ... Counterweight, 20 ... Lift height sensor, 21 ... Load sensor, 22 ... Tilt angle sensor, 23 Accelerator opening sensor, 24 Pitching frequency estimation unit, 25 Pitching detection unit, 26 Motor control unit, 27 Motor rotation speed sensor, 30 Low pass filter.

Claims (5)

A driving wheel is driven by a traveling motor mounted on a vehicle body, and a cargo handling device for loading a load is provided at a front portion of the vehicle body, and a pitching suppressing device for an industrial vehicle provided with a counterweight at a rear portion of the vehicle body. ,
Travel motor control means for controlling the travel motor according to the operation amount of the accelerator operation member;
A rotational speed detecting means for outputting a signal corresponding to the rotational speed of the output shaft of the traveling motor or the driving wheel;
Pitching frequency estimation means for estimating a pitching frequency based on the weight of the load;
The pitching frequency component estimated by the pitching frequency estimation means in the signal corresponding to the rotation speed from the rotation speed detection means is extracted, and the traveling motor is controlled so as to reduce the magnitude of the pitching frequency component. Pitching suppression means to perform,
An industrial vehicle pitching suppression device characterized by comprising:   2. The industrial vehicle pitching suppression device according to claim 1, wherein the pitching frequency estimation means estimates a pitching frequency based on a weight of the load and at least a height position of the load.   3. The industrial vehicle pitching suppression device according to claim 1, wherein the pitching frequency estimation unit estimates a pitching frequency based on a weight of the load and at least a tilt angle of the cargo handling device. 4. A signal corresponding to the operation amount of the accelerator operation member is sent to the travel motor control means via a low-pass filter,
4. The industrial vehicle pitching suppression device according to claim 1, wherein a cutoff frequency of the low-pass filter is changed by a pitching frequency estimated by the pitching frequency estimation unit. 5. A signal corresponding to the operation amount of the accelerator operation member is sent to the travel motor control means via a low-pass filter,
The industrial vehicle pitching suppression device according to any one of claims 1 to 4, wherein the low-pass filter has an attenuation gradient changed according to a magnitude of the pitching frequency component by the pitching suppression unit.

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