JP2624039B2 - Cargo handling control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling control device suitable for use in a forklift for carrying heavy objects, glass, and the like.

[0002]

2. Description of the Related Art Forklifts often carry heavy objects, such as heavy objects and glass, which are vulnerable to impact. FIG.
3 is a block diagram showing a control system of the forklift cargo handling control device. The forklift is moved up and down by the CPU
(Central processing unit) This is performed by controlling the hydraulic pressure of a lift cylinder 2 that lifts and lowers the load by a forklift loading and unloading control device including 1 and the like. When the lift lever 3 is tilted, a lever angle signal S1 proportional to the tilt angle is output as CP.
It is supplied to U1. The CPU 1 outputs a control signal C1 to a motor 5 for driving the pump 4,
The open / close command signal C2 according to a preset pattern as shown in FIG. FIG. 24 shows that when the lift lever 3 is at an angle (on the dotted line in the figure), the opening / closing command signal C2 increases along the solid line shown by the solid line with the passage of time.

Accordingly, the motor 5 drives the pump 4 in a predetermined rotation direction and a predetermined rotation speed according to the control signal C1. The pump 4 pumps up the oil in the tank 7 and supplies it to the lift cylinder 2 via the proportional valve 6. Also,
At this time, the proportional valve opens and closes in response to an open / close command signal C2 from the CPU 1 and controls the amount of oil supplied to the lift cylinder 2. The pressure sensor 8 detects the cylinder pressure and supplies a pressure signal S2 corresponding to the pressure to the CPU 1.
The CPU 1 finely adjusts the control amount of the proportional valve according to the pressure signal S2.

[0004]

In the above-described cargo handling control device, if the lift operation is performed rapidly, the weight of the load may cause the vehicle body to vibrate or the load may be damaged. When performing such a lift operation of a conveyed object, a skilled worker operates the lift lever 3 so that the movement of the lift starts and the moment at which the lift stops is smooth so that the load does not shake.

[0005] The lift operation by a skilled person is intuitive, and has a problem that it is too difficult for a beginner to remember. Therefore, when a beginner operates the lever 3 as described above, there is a concern that the transported article may be damaged. For this reason, there is a need for a cargo handling control device capable of performing a smooth lever operation so that even a beginner does not shake the load as much as an expert.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a cargo handling control device that enables a beginner to perform a smooth operation without causing a load sway for a skilled person without damaging a conveyed object. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, the hydraulic pressure supplied to the lift cylinder loaded with the load is adjusted according to the operation angle of the lift lever. In the cargo handling control device that lifts and lowers the conveyed object by controlling the degree of opening and closing of the proportional valve, a fuzzy control rule based on the operation of a skilled person is based on the operation angle of the lift lever and the lifting speed of the lift cylinder. A fuzzy controller is provided for determining the opening / closing degree of the proportional valve by fuzzy inference and controlling the proportional valve.

According to the second aspect of the present invention, the load is lifted and lowered by controlling the opening / closing degree of a proportional valve that adjusts the hydraulic pressure supplied to the lift cylinder loaded with the load according to the operation angle of the lift lever. In the cargo handling control device, based on the operation angle of the lift lever and the degree of opening and closing of the proportional valve, the amount of correction of the degree of opening and closing of the proportional valve is obtained by fuzzy inference according to a fuzzy control rule based on the operation of a skilled person, A fuzzy controller for controlling the proportional valve is provided.

[0009]

According to the first aspect of the present invention, the proportional valve is opened / closed by the fuzzy controller in which the fuzzy control rule based on the operation of the expert is set based on the operation angle of the lift lever and the elevating speed of the lift cylinder. A degree is determined and the proportional valve is controlled. According to the second aspect of the present invention, the fuzzy controller in which the fuzzy control rule based on the operation of the expert is set allows the opening / closing of the proportional valve based on the operating angle of the lift lever and the opening / closing of the proportional valve. Is calculated, and the proportional valve is controlled.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a control system according to a first embodiment of the present invention. Note that, in this figure, the same components as those shown in FIG. 23 are denoted by the same reference numerals, and description thereof will be omitted. In the first embodiment, the lift cylinder 2
Is provided with a speed sensor 10 for detecting an increasing / decreasing speed of the oil supplied into the cylinder, that is, a rising / falling speed of the lift cylinder, and the speed sensor 10 is proportional to the rising / falling speed of the shift cylinder 2. The speed signal VS1 is supplied to the CPU 11.

A fuzzy control rule based on the operation of a skilled person is set in the CPU 11, and the CPU 11 also operates as a fuzzy controller. That is, the CPU 11 obtains an open / close command signal C2 for the proportional valve 6 by performing fuzzy inference based on the fuzzy rule according to the lever angle signal S1 proportional to the angle of the lift lever 3 and the speed signal VS1. Are supplied to the proportional valve 6. That is, this embodiment is characterized in that fuzzy feedback control is performed according to the lift lever angle and the lift speed.

Next, FIG. 2 shows the membership function of the lift lever angle, FIG. 3 shows the membership function of the lift speed, and FIG. 4 shows the membership function of the opening degree of the proportional valve. S, M, B, NB, NS, Z, PS, PB
Label for membership function. The meaning of each is that label S is "small", label M is "medium",
The label B is “large”, the label NB is “close large”, the label NS is “close slightly”, the label Z is “as is”, the label PS is “slightly open”, and the label PB is “large open”. Further, in this embodiment, all the above-mentioned membership functions use triangular functions. Further, the following nine rules are used as fuzzy control rules.

Fuzzy control rule Rule A1: IF lift lever angle = S and lift speed = S THEN opening of proportional valve = Z Rule A2: IF lift lever angle = S and lift speed = M THEN opening of proportional valve = NS Rule A3: IF lift lever angle = S and lift speed = B THEN proportional valve opening = NB Rule A4: IF lift lever angle = M and lift speed = S THEN proportional valve opening = PS Rule A5: IF lift lever Angle = M and lift speed = M THEN proportional valve opening = Z

Rule A6: IF lift lever angle = M
And lift speed = B THEN proportional valve opening = NS Rule A7: IF lift lever angle = B and lift speed = S THEN proportional valve opening = PB Rule A8: IF lift lever angle = B and lift speed = M THEN Proportional valve opening = PS Rule A9: IF Lift lever angle = B and Lift speed = B THEN Proportional valve opening = Z

In the above-described rules, for example, rule A1 is as follows: "If the lift lever angle is S (small),
Also, if the lift speed is S (slow), the opening degree of the proportional valve should be Z (as it is) ”. FIG. 5 shows these fuzzy control rules. The vertical column in FIG. 5 is a label for the lift lever angle, the horizontal column is a label for the lift speed, and the labels in the table are labels for the opening of the proportional valve. In the control according to the present embodiment, the most general "MIN-MAX centroid method" is adopted as the inference method, but other inference methods may be used.

Next, cargo handling control using the above-described fuzzy inference rules will be described with reference to FIGS. [Operation of the First Embodiment] Here, for example, assuming that the lift lever angle is 0.6 and the lift speed is 0.25, the rules A1 to A9 are actually evaluated, and the opening of the proportional valve 6 is calculated. . First, in the rule A1, as shown in FIG. 6, the suitability of the lift lever angle is 0, and the suitability of the lift speed is 0.5. And their MIN (minimum value)
, The degree of conformity of the open / close command value of the proportional valve 6 to the membership function becomes zero. Similarly, rules A2 and A
Also in the case of No. 3, the suitability of the lift lever angle becomes 0, so that it is not suitable.

Next, according to rule A4, as shown in FIG. 7, the suitability of the lift lever angle is 0.8 and the suitability of the lift speed is 0.5. And those MI
Since N (minimum value) is 0.5, a figure truncated at the position of height 0.5 of the membership function PS of the degree of opening of the proportional valve is obtained. Similarly, in rule A5, the suitability of the lift lever angle is 0.8 and the suitability of the lift speed is 0.5, and the membership function Z of the opening degree of the proportional valve is truncated at the position of height 0.5. The obtained figure is obtained (see FIG. 8). Rules A6 and A9 do not match because the degree of suitability of the lift speed is zero.

According to rule A7, as shown in FIG. 9, the suitability of the lift lever angle is 0.2 and the suitability of the lift speed is 0.5, and if their MIN (minimum value) is taken, 0 is obtained. .2. For this reason, a figure obtained by truncating the membership function PB of the opening degree of the proportional valve 6 at the position of height 0.2 is obtained. Since the MIN (minimum value) of the rule A8 is 0.2 in the same manner as the rule A7, a figure obtained by truncating the membership function PS of the opening degree of the proportional valve 6 at the position of the height 0.2 is obtained. (See FIG. 10).

Next, the figure obtained as a result of the above calculation is
When AX (maximum value) synthesis is performed, the result becomes as shown in FIG.
The result is defuzzified, that is, its center of gravity X
When 1 is taken, this value becomes the opening of the proportional valve 6. This center of gravity X1 is supplied to the proportional valve 6 as an open / close command signal C2.
The proportional valve 6 opens and closes the valve according to the open / close command signal C2 to control the amount of oil sent to the lift cylinder 2.

According to the first embodiment, for example, before the lift starts to fall or before the lift stops, the acceleration of the lift can be reduced to reduce the load sway, so that the conventional forklift control such as PI control can be used. 24, the lift lever angle and the lift speed are always controlled to be the same regardless of the swing of the load or the vibration of the vehicle body.
), An extremely human control can be performed.

Next, a second embodiment of the present invention will be described. [Second Embodiment] FIG. 12 shows a block diagram of cargo handling control by fuzzy control. In this figure, the same components as those shown in FIG. 1 or FIG. 23 are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, an open / close command signal C3 for controlling the opening of the proportional valve 6 is fed back to the CPU 12. A fuzzy control rule based on the operation of a skilled person is set in the CPU 12, and the CPU 12 also operates as a fuzzy controller. That is, the CPU 12
Performs a fuzzy inference based on the fuzzy control rule according to the lever angle signal S1 supplied from the lift lever 3 of the forklift and the open / close command signal C3, thereby newly outputting the open / close command signal C3 for the proportional valve 6.

The open / close command signal C3 for the proportional valve 6 is
This is an increase / decrease value with respect to the current opening degree of the proportional valve 6. That is, in the second embodiment, the lever angle of the lift lever 3 is compared with the opening of the proportional valve 6 to obtain an increase / decrease value with respect to the current opening of the proportional valve 6 (fuzzy feedforward control) (pattern control). Is performed.

Next, FIG. 13 shows the membership function of the lift lever angle, FIG. 14 shows the membership function of the opening degree of the proportional valve, and FIG. 15 shows the opening / closing command value C3 (corresponding to the opening / closing command value) of the proportional valve 6. Here are the membership functions for Labels SS, S, M, B, BB, NM, and PM are labels of membership functions newly added in the present embodiment.

The label SS is "slightly open", the label S is "slightly open", and the label M is "mediumly open" with respect to the opening / closing command value (increase / decrease value) of the proportional valve 6. B means "widely open" and label BB means "very wide open", and the open / close command value C3
Label NM for "close medium", label PM
Means "open medium". In this embodiment, all triangular functions are used. The following ten rules were used as fuzzy control rules.

Fuzzy control rule Rule B1: IF lift lever angle = S and proportional valve opening = SS THEN Proportional valve open / close command value = Z Rule B2: IF lift lever angle = S and proportional valve opening = S THEN Proportional valve opening / closing command value = NS Rule B3: IF lift lever angle = S and proportional valve opening = M THEN Proportional valve opening / closing command value = NB Rule B4: IF lift lever angle = S and proportional valve opening = B THEN Proportional valve open / close command value = NM Rule B5: IF lift lever angle = S and proportional valve opening = BB THEN Proportional valve open / close command value = NS

Rule B6: IF lift lever angle = B
AND proportional valve opening = SS THEN proportional valve opening / closing command value = PS Rule B7: IF lift lever angle = B AND proportional valve opening = S THEN proportional valve opening / closing command value = PM Rule B8: IF lift lever angle = B and proportional valve opening = M THEN proportional valve opening / closing command value = PB Rule B9: IF lift lever angle = B and proportional valve opening = B THEN proportional valve opening / closing command value = PS Rule B10: IF lift Lever angle = S and proportional valve opening = BB THEN Proportional valve open / close command value = Z

In the above-described rules, for example, rule B1 is as follows: "If the lift lever angle is S (small) and the opening of the proportional valve is SS (slightly open), a command to open / close the proportional valve is issued. Change the value C3 to Z (as is) "
It means. These fuzzy rules are shown in FIG.
Shown in The vertical column in FIG. 16 is a label for the lift lever angle, and the horizontal column is a label for the opening of the proportional valve. In the table, labels for the open / close command values of the proportional valve are shown.

Next, cargo handling control using the above-described fuzzy inference rules will be described with reference to FIGS. [Operation of the Second Embodiment] Here, assuming that the lift lever angle is 0.5 and the opening of the proportional valve is 0.4, the rule B
1 to evaluate the rule B10 and calculate the opening and closing of the proportional valve 6. First, in the rule B1, as shown in FIG. 17, the suitability of the lift lever angle is 0.5, and the suitability of the opening of the proportional valve 6 is 0. When these MINs (minimum values) are taken, the degree of conformity of the opening / closing command value C3 of the proportional valve 6 to the membership function becomes zero.

Next, in rule B2, as shown in FIG. 18, the suitability of the lift lever angle becomes 0.5, the suitability of the opening of the proportional valve 6 becomes 0.4, and their MIN
Since (minimum value) is 0.4, a figure obtained by truncating the membership function NS of the proportional valve opening / closing command value C3 at the position of height 0.4 is obtained. Similarly, also in rule B3, the suitability of the lift lever angle is 0.5, and the suitability of the opening of the proportional valve 6 is 0.6. Therefore, a figure is obtained in which the membership function NB of the opening / closing command value of the proportional valve is truncated at the position of height 0.5 (see FIG. 19).

Next, the rules B4 and B5 do not match because the degree of conformity of the opening of the proportional valve 6 is 0. Similarly, the rules B6, B9, and B10 do not conform because the degree of conformity of the opening of the proportional valve 6 is 0. According to the rule B7, as shown in FIG. 20, the suitability of the lift lever angle is 0.5 and the suitability of the opening of the proportional valve 6 is 0.4, so that their MIN (minimum value) is obtained. 0.4. Therefore, a figure is obtained in which the membership function PM of the opening / closing command value C3 of the proportional valve 6 is truncated at the height of 0.4. In the rule B8, the MIN (minimum value) is 0.5 when calculated in the same manner as the rule B7. Therefore, the membership function PB of the opening / closing command value of the proportional valve 6 is truncated at a height of 0.5. A figure is obtained (see FIG. 21).

Next, the figure obtained as a result of the above calculation is
When AX (maximum value) synthesis is performed, the result becomes as shown in FIG.
The result is defuzzified, that is, its center of gravity X
If 2 is taken, this value becomes the opening of the proportional valve 6. This center of gravity X2 is supplied to the proportional valve 6 as an open / close command value C3. The proportional valve 6 opens and closes the valve in accordance with the open / close command value C3 to control the amount of oil sent to the lift cylinder 2.

As described above, according to the first and second embodiments, by applying the fuzzy control to the loading / unloading control of the lift, control very close to the lever operation of an expert can be performed. The same lift operation that does not shake the load is possible.

In the control according to the above-described first and second embodiments, in each case, only two inputs, the lift lever angle and the opening of the proportional valve, or the lift lever angle and the lift speed are used. However, in addition, for example, a pressure signal S proportional to the cylinder pressure from the pressure sensor 8 may be used.
2 is used as an input for fuzzy control, the output of the proportional valve 6 is finely adjusted by fuzzy control, or the vibration of the lift is detected, and the lifting / lowering speed of the lift cylinder 2 is controlled so that the load does not shake. It can also be applied to various controls.

[0034]

As described above, according to the present invention, knowledge about lever operation possessed by a skilled person is taken in as fuzzy control rules, and fuzzy control is applied to forklift loading / unloading control. However, there is an advantage that the skilled person can perform a smooth operation without causing the load to sway without breaking the transported object.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a control system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a membership function of a lift lever angle in the first embodiment.

FIG. 3 is a diagram showing a membership function of a lift speed in the first embodiment.

FIG. 4 is a diagram showing a membership function of the opening degree of the proportional valve in the first embodiment.

FIG. 5 is a diagram illustrating a fuzzy control rule according to the first embodiment.

FIG. 6 is a diagram showing a degree of conformity of a lift lever angle and a degree of lift speed with respect to a rule A1, and a degree of conformity with respect to a membership function of an opening / closing command value of a proportional valve based on a result thereof;

FIG. 7 is a diagram showing the degree of conformity of the lift lever angle and the degree of conformity of the lift speed with respect to the rule A4, and the degree of conformity of the opening degree of the proportional valve with respect to the membership function PS based on the results thereof.

FIG. 8 is a diagram showing the degree of conformity of the lift lever angle with respect to the rule A5, the degree of conformity of the lift speed, and the degree of conformity with respect to the membership function Z of the degree of opening of the proportional valve based on the results thereof.

FIG. 9 is a diagram showing the degree of conformity of the lift lever angle and the degree of conformity of the lift speed to the rule A7, and the degree of conformity to the membership function PB of the opening degree of the proportional valve based on the results thereof.

FIG. 10 is a diagram illustrating the degree of conformity of the lift lever angle and the degree of lift speed with respect to the rule A8, and the degree of conformity of the opening degree of the proportional valve with the membership function PS based on the results thereof.

FIG. 11 is a diagram showing a composite figure of the degree of conformity of the membership function of the degree of opening of the proportional valve with respect to rules A1 to A9.

FIG. 12 is a block diagram illustrating a configuration of a control system according to a second example of the present invention.

FIG. 13 is a diagram showing a membership function of a lift lever angle in the second embodiment.

FIG. 14 is a diagram showing a membership function of the opening degree of the proportional valve in the second embodiment.

FIG. 15 shows an open / close command value C of the proportional valve in the second embodiment.
FIG. 3 is a diagram showing a membership function of No. 3 (corresponding to an opening / closing command value).

FIG. 16 is a diagram illustrating a fuzzy control rule according to the second embodiment.

FIG. 17 is a diagram showing the degree of conformity of the lift lever angle to the rule B1, the degree of conformity of the opening degree of the proportional valve 6, and the degree of conformity of the membership function of the opening / closing command value of the proportional valve 6 based on the results thereof. is there.

FIG. 18 is a diagram showing the degree of conformity of the lift lever angle to the rule B2, the degree of conformity of the opening of the proportional valve 6, and the degree of conformity of the membership function of the opening / closing command value of the proportional valve 6 based on the results thereof. is there.

FIG. 19 is a diagram showing the conformity of the lift lever angle with respect to the rule B3, the conformity of the opening of the proportional valve 6, and the conformity of the membership function of the opening / closing command value of the proportional valve 6 based on the results. is there.

FIG. 20 is a diagram showing the conformity of the lift lever angle to the rule B7, the conformity of the opening of the proportional valve 6, and the conformity of the membership function of the opening / closing command value of the proportional valve 6 based on the results. is there.

FIG. 21 is a diagram showing the degree of conformity of the lift lever angle with respect to the rule B8, the degree of conformity of the opening degree of the proportional valve 6, and the degree of conformity of the membership function of the opening / closing command value of the proportional valve 6 based on the results thereof. is there.

FIG. 22 is a diagram showing a composite figure of the degree of conformity of the membership function of the proportional valve opening / closing command value with respect to rules B1 to B10.

FIG. 23 is a block diagram showing a configuration of a control system of a conventional forklift cargo handling control device.

FIG. 24 is a diagram showing a control pattern of a conventional forklift cargo handling control device.

[Explanation of symbols]

 2 lift cylinder 3 lift lever 4 pump 5 motor 6 proportional valve 7 tank 8 pressure sensor 11, 12 CPU (fuzzy controller)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G05D 16/20 G05D 16/20 A

Claims (2)

(57) [Claims] 1. A cargo handling control device that lifts and lowers a load by controlling the opening / closing degree of a proportional valve that adjusts a hydraulic pressure supplied to a lift cylinder loaded with the load according to an operation angle of a lift lever. A fuzzy controller for controlling the proportional valve by obtaining the degree of opening and closing of the proportional valve by fuzzy inference according to a fuzzy control rule based on an operation of a skilled person based on the operation angle of the lift lever and the elevating speed of the lift cylinder. A cargo handling control device comprising: 2. A cargo handling control device for raising and lowering the load by controlling the opening / closing degree of a proportional valve that adjusts a hydraulic pressure supplied to a lift cylinder loaded with the load according to an operation angle of a lift lever. Based on the operation angle of the lift lever and the degree of opening and closing of the proportional valve, a fuzzy inference according to a fuzzy control rule based on operation of a skilled person is used to obtain a correction amount of the degree of opening and closing of the proportional valve, and a fuzzy control of the proportional valve is performed. A cargo handling control device comprising a controller.