JP2007161396A - Cargo handling control device and cargo handling control method of forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo handling control device and a cargo handling control method of a forklift suitable for starting and stopping operation without causing an operational delay. <P>SOLUTION: This cargo handling device of the forklift has a potentiometer 2 outputting an operation quantity by detecting the operation quantity of an operation lever 1, a controller 4 outputting a calculated control quantity to a solenoid proportional valve 3 by calculating the control quantity to the solenoid proportional valve 3 on the basis of the operation quantity of the operation lever 1, and the solenoid proportional valve 3 controlling a flow rate flowing to an actuator 7 of a cargo handling device on the basis of the inputted control quantity, and changes and outputs the control quantity outputted from the controller 4 on the basis of a rate of change set smaller than a rate of a change in the calculated control quantity in an operation starting area of the starting operation of the cargo handling device from a stopping state and an operation stopping area of stopping the operation from an operation state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cargo handling control device and a cargo handling control method for a forklift that operates a cargo handling device by electrohydraulic control.

  Conventionally, a forklift cargo handling control device that controls the operation of a cargo handling device based on an averaged control amount has been proposed in order to eliminate a sudden change in the control amount and perform smooth cargo handling control (Patent Document 1). reference).

This is based on a potentiometer that detects the operation amount of the operation lever, and a function that inputs the operation amount from the potentiometer and defines the relationship between the operation lever operation amount and the electromagnetic proportional valve control amount from the input operation amount. Calculating a control amount for the electromagnetic proportional valve, averaging the control amount over the control amount a predetermined number of times before, calculating an average control amount, and outputting the control amount, and the controller And an electromagnetic proportional valve for controlling the flow rate flowing through the work implement actuator based on the input control amount.
JP-A-8-133700

  However, in the above conventional example, since the control is based only on the above function that defines the relationship between the addition average value obtained by averaging over the control amount before the predetermined number of times and the electromagnetic proportional valve control amount, the cargo handling operation, for example, There is a problem that if the lever operation is slightly abrupt at the start, stop, lift descent start and stop, the fork starts and stops suddenly and a strong shock occurs.

  Also, as a measure for preventing the shock, the control average is increased by increasing the control average, the control average change is made slowly with respect to the lever operation change amount, and the control current change becomes gentle, and the flow rate change of the electromagnetic proportional valve becomes gentle. If controlled in this way, the fork operation start delay and stop delay occur with respect to the lever operation, and the fork cannot be stopped at a desired position.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a cargo handling control device and a cargo handling control method for a forklift that are suitable for starting and stopping an operation without causing an operation delay.

  The present invention detects an operation amount of an operation lever, calculates a control amount to an electromagnetic proportional valve based on the operation amount of the potentiometer which outputs the operation amount, and the operation lever, and calculates the calculated control amount to the electromagnetic proportional valve A forklift load handling control device comprising: a controller for outputting to the control unit; and an electromagnetic proportional valve for controlling a flow rate flowing to an actuator of the load handling device based on an input control amount, wherein the control amount output from the controller is In the operation start region where the operation is started from the stop state and the operation stop region where the operation is stopped from the operation state, the change is output based on the change rate set smaller than the change rate in the calculated control amount. .

  Therefore, in the present invention, the control amount output from the controller is calculated based on the operation amount of the operation lever in the operation start region where the cargo handling device starts operating from the stopped state and the operation stop region where the operation is stopped from the operating state. The output is changed based on the change rate set smaller than the change rate in the controlled variable. For this reason, the change of the output control current value, which is the control amount in the operation start / stop region of the cargo handling device, can be moderated, and the shock generated when the cargo handling device starts and stops operating can be reduced. Furthermore, since the normal control amount change rate is allowed in the other cargo handling operation regions, the operation delay of the cargo handling device with respect to the operation lever can be minimized.

  Hereinafter, an embodiment of a forklift cargo handling control device and a cargo handling control method according to the present invention will be described with reference to FIGS.

  1 is a schematic configuration diagram of a forklift cargo handling control device, FIG. 2 is a block diagram related to the cargo handling control device of the present invention, FIG. 3 is an output voltage characteristic diagram of a cargo handling lever sensor, and FIG. 4 is an addition of cargo handling lever sensor output voltage. FIG. 5 is a characteristic diagram showing a current change characteristic in the operation start control and the operation stop control, FIG. 6 is a control flowchart of the cargo handling control device, and FIG. FIG. 8 and FIG. 9 are time charts showing an improved example of the cargo handling control device. FIG. 8 is a time chart showing temporal changes in the lever sensor output voltage and the electromagnetic proportional valve control amount.

  In FIG. 1, a forklift cargo handling device includes a potentiometer 2 that detects an operation amount of a lift lever 1 that is an operation lever operated by an operator, and a solenoid proportional valve 3 that rises according to the lever operation amount input from the potentiometer 2. Controller 4 that controls solenoid 3A for lowering and solenoid 3B for lowering, and electromagnetic that is driven by raising solenoid 3A and lowering solenoid 3B to be switched to the neutral position, the raising position, and the lowering position, and its valve opening degree is controlled. Proportional valve 3, pump 5 for supplying hydraulic oil to electromagnetic proportional valve 3, tank 6 for storing hydraulic oil and returning return hydraulic oil from electromagnetic proportional valve 3, and electromagnetic proportional valve 3 to cylinder chamber 7A The hydraulic oil is extended by being supplied and the hydraulic oil is supplied from the cylinder chamber 7A through the electromagnetic proportional valve 3. A lift cylinder 7 as an actuator that contracts by being discharged, is moved up and down by expansion and contraction operation of the lift cylinder 7, and a fork 8 for raising and lowering the loading luggage.

  The cargo handling device controls the electromagnetic proportional valve 3 by the controller 4 in accordance with the direction and amount of operation of the operation lever 1 by the operator. When the cargo is lifted, the hydraulic oil is supplied from the pump 5 to the lift cylinder 7 via the electromagnetic proportional valve 3. The fork 8 is raised and lowered by discharging hydraulic oil from the cylinder chamber 7A of the lift cylinder 7 to the tank 6 via the electromagnetic proportional valve 3 when the cargo handling is lowered.

  As shown in FIG. 3, the potentiometer 2 outputs a predetermined initial output voltage Vi when the operation of the operation lever 1 is positioned in a neutral state including the dead zone, and the lever operation amount is operated beyond the dead zone. In addition, an output voltage VA that increases according to the operation amount exceeding the dead zone is output.

  The controller 4 reads an operation amount based on the output voltage VA input from the potentiometer 2, performs an averaging operation on the operation amount over a predetermined number of times, and calculates an average operation amount. Based on a function that defines the relationship between the amount and the control amount of the electromagnetic proportional valve 3, the control amount to the electromagnetic proportional valve is calculated, and this control amount is output.

  As shown in FIG. 2, the controller 4 includes a ROM that stores control programs and constants, a RAM that stores data that needs to be temporarily stored, a CPU that executes a control program, and a CPU that executes a control process and performs time measurement. A clock C for generating a reference time signal, an A / D converter 4A for converting an analog signal into a digital signal to transmit the analog signal to the CPU, and a D / A conversion for converting the digital signal calculated by the CPU into an analog signal 4B, and an amplifier 4C that outputs a coil current proportional to a command value from the CPU (output of the D / A converter 4B).

  The controller 4 inputs the operation amount from the potentiometer 2 to the CPU via the A / D converter 4A, calculates the control amount to the electromagnetic proportional valve 3 in the CPU, and outputs it to the D / A converter 4B. The control amount is converted from the D / A converter 4B to the coil current via the amplifier 4C and output.

  The electromagnetic proportional valve 3 is driven by the raising solenoid 3A or the lowering solenoid 3B based on the control amount converted into the coil current input from the controller 4, and controls the flow rate flowing to the lift cylinder 7, thereby The direction and speed of operation of the device are controlled.

  The controller 4 calculates the control amount to the electromagnetic proportional valve 3 by calculating the operation lever operation amount average value from the average value obtained by adding and averaging the input operation amount over the operation amount of the operation lever 1 N times before. The control amount to the electromagnetic proportional valve 3 is calculated based on a function that defines the relationship between the operation amount average value and the electromagnetic proportional valve control amount. The function is set as shown in FIG. 4, for example. According to FIG. 4, the rising current at which the solenoids 3 </ b> A and 3 </ b> B of the electromagnetic proportional valve 3 can start operation in a region where the operation amount addition average (voltage) exceeds the initial output Vi in the neutral state including the dead zone of the operation lever 1. Is and falling current Is (for example, 400 to 450 mA), the control amount (output current) I is increased as the operation amount addition average (voltage) increases, and the operation amount addition average (voltage) is the maximum value (for example, 5 [V]), the maximum control amount Imax (the output current is, for example, 1000 mA) is set.

  Further, the controller 4 gradually changes the control amount (output current change) to the electromagnetic proportional valve 3 in the operation start region and the operation stop region of the actuator 7 at the output current value that is the control amount to the electromagnetic proportional valve 3. The operation start control and the operation stop control are provided so as to provide a preset restriction on the control amount (current) change rate. Specifically, as shown in FIG. 5, in the ROM of the controller 4, the output control amount ranges from the rising current value Is (starting current value Ia) to a current value within a predetermined range (ending current value Ib) ( FIG. 5A) and an operation stop region from the current value (start current value Ic) where the output control amount is set in advance to the falling current value Is (end current value Id) (see FIG. 5A) Is set to be a predetermined value (for example, 1 [mA / msec] or less). Thereby, the shock at the start and stop of the operation of the actuator 7 of the cargo handling device is reduced, and the operation delay of the start and stop of the operation of the actuator 7 is also eliminated.

  The processing in the CPU will be described along the flowchart shown in FIG. This flowchart is executed by the CPU every predetermined cycle time (for example, 5 msec).

  First, when power is supplied to the controller 4 in step S1, initialization is performed in the CPU. In step S2, the operation amount (potential voltage V (n)) of the lift lever 1, which is an operation lever, is read from the A / D converter 4A, and the read operation amount is stored in the RAM. Next, in step S3, the current operation amount (V (n)) is added to the stored operation amount (V (nx) +... V (n-2) + V (n-1)) in the past N times. In addition, an average operation of levers (Va (n) is performed by executing an addition average operation [(V (nx) +... V (n-2) + V (n-1) + V (n)) / (X + 1)]. )) Is calculated. In step S4, the control amount (output current value I) to the electromagnetic proportional valve 3 is determined based on a function that defines the relationship between the operation lever operation amount and the electromagnetic proportional valve control amount from the average operation amount (Va (n)). (n)) is calculated.

  Next, in step S5, the current control amount I (n) is compared with the previous control amount I (n-1) to determine whether the control amount is on the increase side or the decrease side. Advances to step S6, and if it is on the decreasing side, advances to step S7.

  In step S6 and step S7, the current control amount I (n) is in a preset operation start region (start current value Ia to end current value Ib) or operation stop region (start current value Ic to end current value Id). If the amount of control is within the range of each region, the process proceeds to step S8 and step S9, respectively. If the current control amount is outside the range of each area, the process proceeds to step S11.

  In step S8 and step S9, the difference current value obtained by subtracting the previous control amount I (m) from the current control amount I (n) is a preset current change rate (for example, 1 [mA / msec]), and the cycle time is If it is 5 msec, the comparison change current value becomes +5 mA or -5 mA), and if the difference current value is larger than the predetermined current change rate, the process proceeds to step S10 and step S12, respectively. If the differential current value is lower than the predetermined current change rate, the process proceeds to step S11.

  In step S11, the current control amount I (n) is output as an output current value as an output current value. In step S13, the current output value (I (n)) is set as the previous output value I (m) in the next time. Then, the current process ends.

  In step S10 and step S12, a predetermined current change value is added to the previous control amount I (m) as the output current value (+5 mA in the increase control) or subtracted (−5 mA in the decrease control), and the current control is performed. A quantity output value (I (m) +5 mA, I (m) -5 mA) is set and output. In step S13, the current output value (I (m) +5 mA, I (m) -5 mA) is set to the previous time in the next time. The output value I (m) is set and the current process is terminated.

  FIG. 7 shows temporal changes in the operation lever operation amount average value (A) and the control amount (B) with respect to the change in the operation amount of the operation lever 1 when the cargo handling device is controlled based on the flowchart shown in FIG. It is a time chart shown respectively.

  In FIG. 7, the operating lever 1 is operated from the neutral position to the ascending position, for example, at the time t1, the operation reaches the maximum lever operating amount at the time t4, and the stop operation is started from the maximum lever operating amount at the time t6. The time-dependent change of the operation lever operation amount average value and the control amount with respect to the state returned to the neutral position at t8 is shown.

  The average value of the operation lever operation amount is obtained by adding and averaging the past several operation amounts of the lever operation amount in FIG. 7A. Therefore, as shown by the broken line, the lever gradually rises from time t1 and increases to some extent. From the time t4 when the lever operation amount reaches the maximum value, the increase rate gradually decreases and gradually approaches the maximum value. Further, it gradually decreases from time t6, decreases in parallel with the lever operation amount when it decreases to some extent, and from time t8 when the lever operation amount becomes zero, the decrease rate gradually decreases and gradually approaches the minimum value. The neutral potential is restored at time t9.

  As shown in FIG. 7B, the control amount to the electromagnetic proportional valve based on the transition of the operation lever operation amount average value is executed by step S5, step S6, step S8, and step S10 of the flowchart at time t1. As shown by the broken line, the output current value I (n) is controlled to increase from the rising current value Is (start current value Ia of operation start control) at a predetermined current change rate (I (m) +5 mA). At the cycle time after time t2 when the start region (end current value Ib) is exceeded, the output current value I (n) is returned to step S6 and step S11 (time t3), and the subsequent controlled variable is shown by a solid line. Furthermore, the characteristics increase based on the transition of the lever operation amount average value.

  Therefore, at the start of the operation of the cargo handling device, the above operation start control is executed between the time points t1 and t2, and the flow rate characteristic of the electromagnetic proportional valve 3, that is, the operation start speed of the cargo handling device is moderated by the preset current change rate. Therefore, the shock at the start of the operation can be reduced, and the time for setting the control amount at a predetermined current change rate is changed from the rising current value Is (start current value Ia) to the predetermined current value (end current value Ib). Since it is set only between the increasing time points t1 and t2, the operation delay at the start of operation of the cargo handling device can be reduced as much as possible.

  Even when the lever operation amount average value is decreased, the output current value I (n) is decreased between the time t6 and the time t7 as shown by the solid line based on the steps S7 and S11. Steps S7, S9, and S12 are executed from time t7 after time t7 when entering the operation stop region to time t9, and, as indicated by the broken line, a predetermined current change rate (I ( m) The characteristic is controlled to decrease at -5 mA). After time t9, step S7 and step S11 are executed, and as shown by the broken line up to time t10, the current falls to the falling current Is.

  Therefore, when the cargo handling device is stopped, the operation stop control is executed between time points t7 and t9, and the flow rate characteristic of the electromagnetic proportional valve 3, that is, the operation stop speed of the cargo handling device is moderated by the preset current change rate. Therefore, when the operation is stopped, the shock can be reduced and the time for setting the control amount at the predetermined current change rate is decreased from the start current value Ic to the fall current value Is (end current value Id) t7. Since it is set to only between t9, the operation delay when the operation of the cargo handling device is stopped can be reduced as much as possible.

  In the operation start control, it is desirable to set the start current value Ia as close as possible to the rising current value Is or the rising current value Is so as to reduce the acceleration when the cargo handling apparatus starts moving, and stop the operation. In the control, it is desirable to set the end current value Id to be close to the falling current value Is or the falling current value Is so as to reduce the acceleration when the cargo handling device stops.

  And each control region of the operation start control and the operation stop control needs to be provided with appropriate control ranges, respectively, in order to obtain the maximum shock reduction effect while minimizing the operation delay of the cargo handling device, It is desirable to narrow the control range set by the start current values Ia and Ic and the end current values Ib and Id, and it is about the effective current range set by the rising (falling) current value Is and the maximum current value Imax. It is desirable to make it less than half.

  Further, the current change rate in the operation start control and the operation stop control is expressed as effective current value × 0, where the controllable current value between the rising (falling) current value Is and the maximum current value Imax is an effective current value. By setting it to 0.006 [mA / msec] or less, a sufficient shock reduction effect can be obtained. By providing a restriction on the current change rate in this way, it is possible to easily control the start and stop of the operation of the cargo handling device, and to reduce shocks reliably.

  In the above embodiment, the start current value Ia of the operation start control and the end current value Id of the operation stop control are the rising and falling current values Is of the solenoids 3A and 3B of the electromagnetic proportional valve 3, and the end current value of the operation start control is set. A case has been described in which Ib and the start current value Ic of the operation stop control are set to the same current value, and the current change rate during the control uses the same change rate. However, it is desirable that the start current values Ia and Ic and the end current values Ib and Id of these controls are set to optimum values in the operation start control and the operation stop control, respectively. In addition, the predetermined current change rate is preset and can be changed, but it is desirable to set optimum values in the operation start control and the operation stop control. If it is set to a value that matches the type, a better feeling can be obtained.

  In the improved example 1 shown in FIG. 8, the current change rate in the operation start control and the operation stop control is the same, but the end current value Ib in the operation start control and the start current value Ic in the operation stop control are set to different current values. It is a thing. That is, the start current value Ia in the operation start control and the end current value Id in the operation stop control are set to rise and fall current values Is, for example, 420 [mA], and the end current value Ib of the operation start control is, for example, The starting current value Ic in the operation stop control is set to 740 [mA], for example. The current change rate in the operation start control and the operation stop control is set to 1 [mA / msec] or less.

  Thus, by increasing the operation stop control start current value Ic with respect to the operation start control end current value Ib, the operation stop control start time t7 is advanced, and the operation stop control control time t7 to t9 is lengthened. The inertial energy that can be relaxed can be increased.

  As described above, by increasing the start current value Ic of the operation stop control relative to the end current value Ib of the operation start control, the operation delay due to each control is suppressed (required control time is shortened), and the operation stop time It is possible to effectively suppress the occurrence of a stop shock. That is, the magnitude of shock is different between the operation start region and the operation stop region of the cargo handling device, particularly the lifting device. In particular, since the inertia of the lifting device acts on the operation stop region side, if the stopping speed is high, the lifting device is likely to jump up and a strong shock is generated.

  In the improved example 1, the current change rate is set to the same rate of change in the operation start control and the operation stop control, but may be set to different current change rates. For example, the stop shock on the operation stop region side may be further alleviated by setting the current change rate in the operation stop control smaller than the current change rate in the operation start control.

  In the improved example 2 shown in FIG. 9, the start current value Ia of the operation start control is made larger than the rising current value Is, and the end current value Id of the operation stop control is made larger than the falling current value Is. Thus, by narrowing the control range of the operation start control and the operation stop control to the limit, the start timing of the operation start control is delayed from time t1 to time t11, and the end timing of operation stop control is changed from time t9 to time t12. Accordingly, the operation delay of the cargo handling device with respect to the operation lever 1 can be minimized.

  In the above embodiment, only the operation start and the operation stop have been described as the operation of the cargo handling device. Although not illustrated, when the cargo handling device is a lift device (mast), the start and stop of the lift are performed. In the case of a tilt device, it includes a forward tilt start, a forward tilt stop, a rear tilt start and a rear tilt stop, and also starts and stops various devices including other attachments. You may apply to.

  In the above embodiment, as the control amount calculation method, the input operation amount is averaged over a predetermined number of previous operation amounts to calculate an average operation amount, and the average operation amount and the electromagnetic proportional valve 3 are calculated. Although the calculation is based on a function that defines the relationship between the control amount and the control amount, although not shown, a function that defines the relationship between the operation lever operation amount and the electromagnetic proportional valve control amount from the input operation amount On the basis of this, the control amount to the electromagnetic proportional valve may be calculated, the control amount may be averaged over the control amount a predetermined number of times, and the average control amount may be calculated. Further, the control amount may be calculated by other means without using the above-described averaging calculation.

  In the present embodiment, the following effects can be achieved.

  (A) The operation amount of the operation lever 1 is detected, the potentiometer 2 that outputs the operation amount, the control amount to the electromagnetic proportional valve 3 is calculated based on the operation amount of the operation lever 1, and the calculated control amount is A forklift loading / unloading control device comprising a controller 4 for outputting to an electromagnetic proportional valve 3 and an electromagnetic proportional valve 3 for controlling a flow rate flowing to an actuator 7 of the loading / unloading device based on an input control amount. The control amount to be output is based on the change rate set to be smaller than the change rate in the calculated control amount in the operation start region where the cargo handling device starts operation from the stop state and the operation stop region where the operation is stopped from the operation state. The output is changed. For this reason, the change of the output control current value, which is the control amount in the operation start / stop region of the cargo handling device, can be moderated, and the shock generated when the cargo handling device starts and stops operating can be reduced. Furthermore, since the normal control amount change rate is allowed in other cargo handling operation regions, the operation delay of the cargo handling device with respect to the operation lever 1 can be minimized.

  (A) The operation start region where the cargo handling device starts to operate from the stop state is the start current value Is or the current value approximated to the current value Is of the electromagnetic proportional valve 3 or the maximum value from the current value Is. An operation stop region where the current value in the middle of the current value Imax is set to a control amount range in which the end control value Ib is set and the cargo handling device is stopped from the operating state is established from the maximum current value Imax of the electromagnetic proportional valve 3. A control amount range in which the current value in the middle of the falling current value Is is set as the start control value Ic and the falling current value Is of the electromagnetic proportional valve 3 or the current value approximate to the falling current value Is is set as the end control value Id. By setting, the operation start area can be set to match the operation rising area of the electromagnetic proportional valve 3, and the operation stop area can be set to match the operation falling area of the electromagnetic proportional valve 3, While reducing the operation start time and operation stop time of the shock can be suppressed its operation delay.

  (C) By setting the operation start region and the operation stop region to different control amount ranges, appropriate control ranges are set for the operation start region and the operation stop region of the cargo handling device having different magnitudes of shocks. The maximum shock reduction effect can be obtained while minimizing the operation delay.

  (D) The control amount change rate in the operation start region and the operation stop region is set to different change rates, so that it is appropriate for the operation start region and the operation stop region of the cargo handling device having different magnitudes of shock. Therefore, the control rate change rate, that is, the current change rate can be set, and the maximum shock reduction effect can be obtained while minimizing the operation delay.

  (E) The operation start region and the operation stop region are set to different control amount ranges and set to different control amount change rates, whereby the operation start region and the operation stop region of the cargo handling device having different magnitudes of shocks, For example, by setting an appropriate current region and current change rate that are independent of the lift start and lift stop operation start region and the operation stop region, the maximum shock reduction effect can be obtained while minimizing the operation delay. it can.

  (F) The control amount to be calculated is obtained by averaging the input operation amount over the operation amount of a predetermined number of times, calculating the average operation amount, and calculating the average operation amount and the control amount to the electromagnetic proportional valve 3 Is calculated based on a function that defines the relationship of the above, or based on a function that defines the relationship between the operation lever operation amount and the electromagnetic proportional valve control amount from the input operation amount, By calculating the control amount, averaging the control amount over the control amount of the previous number of times, and calculating the average control amount, it is possible to eliminate a sudden change in the control amount and facilitate smooth control It is possible to reduce the demand for skill and mental burden on the operator, and to enable a beginner to easily and safely carry out the cargo handling work.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the cargo handling control apparatus of the forklift which shows one Embodiment of this invention. The block diagram which similarly concerns on a cargo handling control apparatus. The output voltage characteristic figure of a cargo handling lever sensor. The characteristic view which defined the relationship between the addition average value of a cargo handling lever sensor output voltage, and an electromagnetic proportional valve control amount. The characteristic view which shows the electric current change characteristic in operation | movement start control and operation | movement stop control. The control flowchart of a cargo handling control apparatus. The time chart which shows the time change of a cargo handling lever sensor output voltage and an electromagnetic proportional valve control amount. The time chart which shows the modification 1 of a cargo handling control apparatus. The time chart which shows the example 2 of improvement of a cargo handling control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lift lever as an operation lever 2 Potentiometer 3 Solenoid proportional valve 4 Controller 5 Pump 6 Tank 7 Lift cylinder as an actuator 8 Fork as a cargo handling device

Claims (8)

A potentiometer that detects the operation amount of the operation lever and outputs the operation amount, and a controller that calculates the control amount to the electromagnetic proportional valve based on the operation amount of the operation lever and outputs the calculated control amount to the electromagnetic proportional valve And an electromagnetic proportional valve that controls the flow rate of the flow of the actuator of the cargo handling device based on the input control amount.
In the operation start region where the cargo handling device starts operating from the stopped state and the operation stop region where the operation is stopped from the operating state, the controller controls the amount of control based on the change rate set smaller than the change rate in the calculated control amount. A forklift cargo handling control device characterized in that the output is changed. The operation start region in which the cargo handling device starts to operate from a stopped state is a midway step from the rising current value to the maximum current value with the current value approximated to the rising current value or the rising current value of the electromagnetic proportional valve as the start control value. Set to a control amount range with the current value as the end control value,
The operation stop region in which the operation of the cargo handling device is stopped from the operating state is a current value in the middle stage from the maximum current value of the electromagnetic proportional valve to the falling current value as a start control value and the falling current value of the electromagnetic proportional valve or 2. The cargo handling control device for a forklift according to claim 1, wherein the load control device is set to a control amount range in which a current value approximate to a falling current value is set as an end control value.   The forklift cargo handling control device according to claim 1 or 2, wherein the operation start region and the operation stop region are set to different control amount ranges.   The forklift cargo handling control device according to claim 1 or 2, wherein the control amount change rates in the operation start region and the operation stop region are set to different change rates.   The forklift cargo handling control device according to claim 1 or 2, wherein the operation start region and the operation stop region are set to different control amount ranges and set to different control amount change rates.   The calculated control amount is obtained by averaging the input operation amount over a predetermined number of previous operation amounts, calculating an average operation amount, and indicating the relationship between the average operation amount and the control amount to the electromagnetic proportional valve. Calculate based on a defined function, or calculate the control amount to the solenoid proportional valve based on a function that defines the relationship between the control lever operation amount and the solenoid proportional valve control amount from the input operation amount 6. The control amount according to any one of claims 1 to 5, wherein the control amount is averaged over the control amount a predetermined number of times before to calculate an average control amount. Forklift cargo handling control device. Industrial vehicle cargo handling control method in which an electromagnetic proportional valve interposed in a hydraulic circuit connecting a hydraulic power source and an actuator of a cargo handling device is controlled by a control amount calculated by a controller based on an operation signal from an operation lever In
While the operation amount of the operation lever passes through the activation region from the operation position at which the cargo handling device starts to operate to a preset operation amount and the stop region from the preset operation amount to the operation position at which the cargo handling device is stopped. A forklift cargo handling control method, wherein the control amount is changed and output based on a change rate set smaller than the change rate in the calculated control amount. The start range is a control amount range in which the starting current value of the electromagnetic proportional valve or a current value approximated to the rising current value is a start control value, and the current value in the middle stage from the rising current value to the maximum current value is an end control value. Set to
In the stop region, the current value in the middle stage from the maximum current value of the electromagnetic proportional valve to the falling current value is set as the start control value, and the current value approximated to the falling current value or the falling current value of the electromagnetic proportional valve is ended. The forklift cargo handling control method according to claim 7, wherein the control amount range is set as a control value.

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