JP6501168B1 - Traveling control device and industrial vehicle - Google Patents

Abstract

A travel control device and an industrial vehicle capable of obtaining a predetermined maximum speed without being affected by a warm air condition or a travel resistance. SOLUTION: A first detection unit 2 for detecting an accelerator operation amount, a second detection unit 3 for detecting a rotational speed of a traveling motor 20, and a storage unit 5 storing torque curve data related to a torque curve of the traveling motor 20. And a control unit 6 that determines a target torque of the traveling motor 20, and an inverter unit 7 that controls the traveling motor 20 according to the target torque. The storage unit 5 stores time data obtained by measuring the time until the rotational speed reaches the maximum speed. The control unit 6 continues the first process of measuring the duration time of the full acceleration state, and the second process of determining the arrival time from reaching the full acceleration state to reaching the maximum speed with reference to time data, and And a third process of performing a correction of increasing the torque curve by the first correction torque when the time is greater than the arrival time. [Selected figure] Figure 1

Description

  The present invention relates to a travel control device and an industrial vehicle.

  In industrial vehicles such as battery forklifts, the maximum torque of a traveling motor that can be output according to traveling speed is limited (see, for example, Patent Document 1). Specifically, as shown by the torque curve in FIG. 5, the maximum torque determined by the maximum allowable current of the traveling motor is output in the low speed region, while the maximum torque gradually decreases as the traveling speed increases in the medium and high speed region. It is restricted to.

  The torque curve is set to reach the maximum speed when the vehicle is fully warmed up (warmed up). On the other hand, when the vehicle is not sufficiently warmed up (non-warmed condition), the viscosity resistance of the gear oil in the driving force transmission mechanism is increased or the rolling resistance of the drive wheel is increased as compared to the warmed state. , Driving resistance increases. As the driving resistance increases, the driving torque also increases, so the maximum speed in the warm-up state can not be reached.

For example, the torque curve in FIG. 5, the travel speed V _E corresponding to the torque T _E of the warm state is assumed to be the maximum speed. In a non-warming state immediately after the start of driving, etc., when the running resistance increases and the torque increases to reach T _F , the running speed decreases to become V _F (the maximum speed V _E is not reached). Further, since running resistance also varies with break-in time and parts accuracy, the running resistance even in warm state is large, may not reach the maximum speed V _E.

Unexamined-Japanese-Patent No. 2003-267697

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a travel control device and an industrial vehicle capable of obtaining a predetermined maximum speed without being affected by a warm air condition or a travel resistance. It is in.

In order to solve the above-mentioned subject, the traveling control device concerning the present invention is:
A travel control device that controls a travel motor according to an accelerator operation amount,
A first detection unit that detects the accelerator operation amount;
A second detection unit that detects a rotational speed of the traveling motor;
A storage unit storing torque curve data related to a torque curve of the traveling motor;
A control unit that determines a target torque of the traveling motor based on the accelerator operation amount, the rotational speed, and the torque curve;
An inverter unit that controls the traveling motor according to the target torque;
Equipped with
The storage unit stores time data obtained by measuring the time until the rotational speed reaches the maximum speed,
The control unit
A first process of measuring a duration of a full accelerator state in which the accelerator operation amount is maximum;
A second process of determining an arrival time from the full acceleration state to the maximum speed with reference to the time data;
And performing a third process of performing a correction of increasing the torque of the torque curve by a first correction torque when the duration is greater than the arrival time.

The control unit performs correction to torque down the torque curve by a second correction torque when the rotation speed has reached the maximum speed and the duration is smaller than the arrival time. It is preferable to execute 4 treatments.

  The control unit may increase the correction amount of the torque curve as the difference between the rotational speed and the maximum speed is larger.

  The control unit may return the torque curve to a state before correction when the full acceleration state is released.

  The control unit may maintain the corrected state of the torque curve while the full acceleration state is released.

Moreover, in order to solve the said subject, the industrial vehicle which concerns on this invention,
One of the above-described travel control devices is provided.

  According to the present invention, it is possible to provide a travel control device and an industrial vehicle that can obtain a predetermined maximum speed without being affected by the warm air condition or the travel resistance.

It is a figure showing composition of a run control device concerning the present invention. (A) It is a figure which shows an example of the torque curve data of this invention. (B) It is a figure which shows an example of the time data of this invention. It is a control flowchart of the traveling control device concerning the present invention. (A) It is a figure for demonstrating the torque up correction | amendment in this invention. (B) It is a figure for demonstrating the torque down correction | amendment in this invention. It is a figure which shows the conventional torque curve.

  Hereinafter, with reference to the accompanying drawings, embodiments of a travel control device according to the present invention and a forklift as a preferred example of an industrial vehicle according to the present invention will be described.

  A forklift according to an embodiment of the present invention includes an accelerator lever, a cargo handling lever (lift lever, tilt lever and reach lever), a cargo handling device, a drive wheel, and the like.

  The cargo handling apparatus includes each cylinder (lift cylinder, tilt cylinder and reach cylinder), a carriage, a pair of left and right masts erected on the carriage, and a pair of left and right forks movably mounted on the mast. For example, the fork can be raised and lowered by the lift cylinder, the fork can be inclined by the tilt cylinder, and the carriage can be moved back and forth by the reach cylinder.

  Moreover, the forklift according to the present embodiment includes a traveling control device 10 and a traveling motor (electric motor) 20, as shown in FIG. When the operator of the forklift operates the accelerator lever, the travel control device 10 rotates the traveling motor 20 according to the amount of operation of the accelerator lever to drive the drive wheels.

  The traveling control device 10 includes an accelerator sensor 2 (corresponding to the “first detection unit” of the present invention), a speed sensor 3 (corresponding to the “second detection unit” of the present invention), a load sensor 4, and a storage unit 5. , Controller 6, and a controller 1 including an inverter unit 7.

  The accelerator sensor 2 is, for example, a potentiometer, and detects an accelerator operation amount corresponding to a tilt angle of the accelerator lever. The accelerator sensor 2 outputs the detected accelerator operation amount to the control unit 6 at a predetermined cycle.

  The speed sensor 3 is, for example, a bearing sensor, and detects the rotational speed of the traveling motor 20. The speed sensor 3 outputs the detected rotational speed to the control unit 6 at a predetermined cycle. The control unit 6 converts the rotational speed into the traveling speed of the forklift.

  The load sensor 4 is provided, for example, in the middle of the pipe connected to the lift cylinder, and detects the load of the load loaded on the fork based on the hydraulic pressure in the pipe. The load sensor 4 outputs the detected load to the control unit 6 at a predetermined cycle.

  The storage unit 5 is formed of, for example, a storage device such as a memory. The storage unit 5 stores torque curve data and time data.

The torque curve data is data on a torque curve of the traveling motor 20, as shown in FIG. As can be seen from the drawing, in the low speed region, the maximum torque is determined by the maximum allowable current of the traveling motor 20, while in the middle and high speed region, the maximum torque is limited to gradually decrease as the traveling speed increases.

Time data, as shown in FIG. 2 (B), (in other words, the rotational speed of the traveling motor 20) the running speed of the forklift is data obtained by measuring the time to reach the maximum velocity V _MAX. More specifically, it is data obtained by measuring the traveling speed at the time of the full acceleration state where the accelerator operation amount is maximum and the arrival time until the maximum speed V _MAX is reached from the full acceleration state. For example, to full acceleration state at time _{t 1,} the maximum speed _V when it reaches the _MAX, the traveling speed _{V 1} and the arrival time at time _{t 1} at time _{t 2 (t 2} -t ₁₎ and a storage unit as the time data It is stored in 5. In this embodiment, after the no-load (load [0 kg]) forklift is warmed up, the arrival time is measured at a predetermined speed increment (e.g., 1 km / s increment).

  The control unit 6 is, for example, a microcomputer. The control unit 6 determines the target torque of the traveling motor 20 based on the accelerator operation amount, the rotational speed, and the torque curve of the torque curve data.

  For example, the control unit 6 determines the target rotational speed of the traveling motor 20 in accordance with the accelerator operation amount input from the accelerator sensor 2. Next, the control unit 6 determines a temporary target torque in accordance with the difference between the target rotational speed and the current rotational speed of the traveling motor 20. Next, the control unit 6 compares the maximum torque determined by the torque curve with the temporary target torque to determine the target torque. Then, the control unit 6 drives the inverter unit 7 according to the target torque.

  The inverter unit 7 controls the traveling motor 20 in accordance with the target torque.

  In addition, the control unit 6 includes a counter that measures the duration of the full acceleration state, and performs correction (torque correction) to torque up or torque down the torque curve of the torque curve data according to the duration. The counter is configured by, for example, a digital circuit (logic circuit).

  FIG. 3 shows a control flow of the control unit 6 at the time of torque correction. As shown in FIG. 3, the control unit 6 determines whether or not the forklift is not loaded based on the load input from the load sensor 4 (S1). The control unit 6 determines that no load occurs when the load is 0 kg (YES in S1), and determines that no load occurs when the load is not 0 kg (NO in S1). When S1 is NO, the control unit 6 resets the duration time measured by the counter to 0 (S2), and executes the process of S1 again.

  In the case of YES in S1, the control unit 6 determines, based on the accelerator operation amount input from the accelerator sensor 2, whether or not it is in the full accelerator state (S3). The control unit determines that the accelerator operation amount is maximum when it is determined to be a full accelerator state (YES in S3), and determines that the accelerator operation amount is not a full accelerator state when it is not reached (NO in S3). . In the case where S3 is NO, the control unit 6 resets the duration measured by the counter to 0 (S2), and executes the process of S1 again.

  In the case of YES in S3, the control unit 6 determines whether or not the duration of the counter is 0 (S4). If the duration of the counter is 0 (YES in S4), the control unit 6 calculates the current traveling speed of the forklift based on the detection result of the speed sensor 3 and holds the calculated traveling speed (S5). This traveling speed corresponds to the traveling speed when full acceleration is achieved. Further, the control unit 6 holds the traveling speed and causes the counter to start measurement of the duration (S5). This process corresponds to the "first process" of the present invention.

Next, the control unit 6 refers to the time data to determine the arrival time from the held traveling speed to reaching the maximum speed V _MAX (S6). This process corresponds to the "second process" of the present invention. For example, when the traveling speed held is V ₁ , the arrival time is determined to (t ₂ −t ₁ ) (see FIG. 2 (B)).

  If NO in S4 or if the arrival time is determined in S6, the control unit 6 adds a predetermined time to the duration of the counter (S7). The predetermined time is determined by the control cycle of the control unit 6. In the present embodiment, since the control cycle is 1 ms, the control unit 6 adds 1 ms to the duration of the counter. When the control cycle is 2 ms, 2 ms is added to the duration of the counter.

  Next, the control unit 6 determines whether the duration is equal to or less than the arrival time (S8). When the control unit 6 determines that the duration time is longer than the arrival time (NO in S8), the control unit 6 performs a correction to increase the torque curve by the first correction torque (for example, 0.1 N · m) (S9) . This process corresponds to the "third process" of the present invention.

The value of the first correction torque may be changed as appropriate, but as shown in FIG. 4A, it is limited to the maximum torque determined by the maximum allowable current of the traveling motor 20 in the low speed region. Further, as shown in the figure, the running speed V _B corresponding to the torque T _B in warm conditions the maximum speed, if the torque of the non-warm-up state, such as immediately after the start of the operation was T _A, corresponding to the torque T _A The traveling speed is V _A (<V _B ), but by increasing the torque curve, the traveling speed increases from V _A to V _B which is the maximum speed. That is, in the present embodiment, a predetermined maximum speed can be obtained without being affected by the warm air condition or the running resistance.

  The control unit 6 that has performed the torque-up correction in S9 resets the duration measured by the counter to 0 (S2), and executes the processing of S1 again.

  In the case of YES in S8, that is, in the case where the duration time is equal to or less than the arrival time, the control unit 6 determines whether the current traveling speed is equal to or higher than the maximum speed (S10). The control unit 6 calculates the current traveling speed of the forklift based on the detection result of the speed sensor 3. When it is determined that the current traveling speed has not reached the maximum speed (NO in S10), the control unit 6 executes the process of S1 again.

  When the control unit 6 determines that the current traveling speed is equal to or higher than the maximum speed (YES in S10), the control unit 6 determines whether the duration is equal to or more than the arrival time (S11). When the control unit 6 determines that the duration time is equal to or more than the arrival time (YES in S11), the control unit 6 executes the process of S1 again.

  When the control unit 6 determines that the duration time is smaller than the arrival time (NO in S11), the control unit 6 performs correction to torque down the torque curve by the second correction torque (for example, 0.1 N · m) (S12) . This process corresponds to the "fourth process" in the present invention.

Although the value of the second correction torque may be changed as appropriate, as shown in FIG. 4B, in the low speed region, the maximum torque determined by the maximum allowable current of the traveling motor 20 is obtained. Also, as shown in the figure, when the traveling speed V _C corresponding to the torque T _C at normal traveling resistance is the maximum speed, and the torque at low traveling resistance is T _D , the torque T _D is supported. The traveling speed becomes V _D and the maximum speed V _C is exceeded. The control unit 6 reduces the torque curve from torque to return the traveling speed from V _D to V _C , which is the original maximum speed. That is, in the present embodiment, a predetermined maximum speed can be obtained without being affected by the warm air condition or the running resistance.

  The control unit 6 that has performed the torque down correction in S12 resets the duration measured by the counter to 0 (S2), and executes the process of S1 again.

  In the present embodiment, the torque curve data corrected for torque up or torque down is maintained even when the full acceleration state is released. In other words, the control unit 6 determines the target torque based on the corrected torque curve even if the full acceleration state is released.

  The embodiments of the travel control device and the industrial vehicle according to the present invention have been described above, but the present invention is not limited to the embodiments.

  For example, in the control flow of the control unit 6 at the time of torque correction, the processing of S11 and S12 related to the torque down correction may be omitted.

  The control unit 6 calculates the difference between the traveling speed of the forklift (the rotational speed of the traveling motor 20) and the maximum speed when performing the torque up correction (S9) or the torque down correction (S12), and the larger the difference is, The correction amount of the torque curve may be increased. Thereby, the predetermined maximum speed can be obtained earlier than the above embodiment.

  The control unit 6 may return the torque curve to the state before the correction when the full acceleration state is released. Thus, when the full acceleration state is released, the torque curve data returns to the initial state when stored in the storage unit 5.

  In the above embodiment, torque correction is performed only when the forklift is unloaded, but torque correction can be performed even when there is a load, that is, even when a load is mounted on the fork. In this case, it is necessary to generate time data in the presence of a load (for example, changing the load in increments of 100 kg).

  The control unit 6 determines whether or not the duration is smaller than the arrival time + the predetermined time (for example, 1s) in S8 of the control flow of FIG. 3, and the duration is the arrival time in S11 of the control flow. It may be determined whether or not it is longer than a predetermined time (for example, 1 s). This makes it possible to reduce the number of torque corrections when the difference between the duration and the arrival time is small.

  The industrial vehicle of the present invention may be a vehicle other than a forklift as long as it performs cargo handling work.

1 controller 2 accelerator sensor (first detector)
3 Speed sensor (second detector)
4 load sensor 5 storage unit 6 control unit 7 inverter unit 10 traveling control device 20 traveling motor

Claims (6)

A travel control device that controls a travel motor according to an accelerator operation amount,
A first detection unit that detects the accelerator operation amount;
A second detection unit that detects a rotational speed of the traveling motor;
A storage unit storing torque curve data related to a torque curve of the traveling motor;
A control unit that determines a target torque of the traveling motor based on the accelerator operation amount, the rotational speed, and the torque curve;
An inverter unit that controls the traveling motor according to the target torque;
Equipped with
The storage unit stores time data obtained by measuring the time until the rotational speed reaches the maximum speed,
The control unit
A first process of measuring a duration of a full accelerator state in which the accelerator operation amount is maximum;
A second process of determining an arrival time from the full acceleration state to the maximum speed with reference to the time data;
And a third process of performing correction that causes the torque curve to be torqued up by a first correction torque when the duration is greater than the arrival time. The control unit performs correction to torque down the torque curve by a second correction torque when the rotation speed has reached the maximum speed and the duration is smaller than the arrival time. The travel control device according to claim 1, wherein the four processes are executed.
The travel control device according to claim 1, wherein the control unit increases the correction amount of the torque curve as the difference between the rotational speed and the maximum speed is larger. The travel control device according to any one of claims 1 to 3, wherein the control unit returns the torque curve to a state before correction when the full acceleration state is released. The travel control device according to any one of claims 1 to 3, wherein the control unit maintains the state after the correction of the torque curve while the full acceleration state is released. An industrial vehicle comprising the travel control device according to any one of claims 1 to 5.

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