JP7639636B2 - Center of gravity estimation device for industrial vehicles - Google Patents

Description

The present invention relates to a center of gravity estimation device for an industrial vehicle.

As an example of a center of gravity estimation device for an industrial vehicle, as described in Patent Document 1, a technology is known that detects the pressure in the tilt cylinder and lift cylinder of a forklift and estimates the center of gravity position of the load held by the forks based on the pressure in the tilt cylinder and the pressure in the lift cylinder.

JP 2020-93741 A

In order to estimate the position of the center of gravity of a load with high accuracy, it is necessary to accurately determine the center of gravity of each of the mast and forks after the load is held by the forks. However, in the case of forklifts, the mast and attachments (holding parts) such as forks may be custom-made products. For this reason, if one tries to obtain the center of gravity for all masts and attachments, the amount of work required to estimate the center of gravity may increase.

The object of the present invention is to provide a center of gravity estimation device for an industrial vehicle that can improve the accuracy of estimating the center of gravity position of a load held in a holding section while reducing the amount of work required.

One aspect of the present invention is a center of gravity estimation device for an industrial vehicle equipped with a loading device having a holding section attached to a mast and holding a load, a lift cylinder for raising and lowering the holding section, and a tilt cylinder for tilting the mast. The device is equipped with a memory section for storing data on the structure of the loading device, a weight detection section for detecting the weight of the load held in the holding section, a tilt state detection unit for detecting the state of the tilt cylinder before the load is held in the holding section and the state of the tilt cylinder after the load is held in the holding section, and a center of gravity estimation calculation section for estimating the position of the center of gravity of the load in the fore-and-aft direction of the body of the industrial vehicle based on the weight of the load, the state of the tilt cylinder before and after the load is held in the holding section, and data on the structure of the loading device.

In such a center of gravity estimation device, the weight of the luggage held in the holding section is detected, as well as the state of the tilt cylinder before the luggage is held in the holding section and the state of the tilt cylinder after the luggage is held in the holding section. Then, an estimation calculation is performed for the position of the center of gravity of the luggage in the fore-and-aft direction of the vehicle body based on the weight of the luggage, the state of the tilt cylinder before and after the luggage is held in the holding section, and data related to the structure of the loading device. In this way, the position of the center of gravity of the luggage held in the holding section is estimated without obtaining the respective centers of gravity of the mast and the holding section. This reduces the amount of work required to estimate the center of gravity, while improving the accuracy of the estimation of the position of the center of gravity of the luggage held in the holding section.

The tilt state detection unit has a rod pressure detection unit that detects the pressure in the rod chamber of the tilt cylinder, a bottom pressure detection unit that detects the pressure in the bottom chamber of the tilt cylinder, and a tilt thrust calculation unit that calculates the thrust of the tilt cylinder before the luggage is held in the holding section and the thrust of the tilt cylinder after the luggage is held in the holding section based on the pressure in the rod chamber of the tilt cylinder and the pressure in the bottom chamber of the tilt cylinder, and the center of gravity estimation calculation unit may estimate the center of gravity position of the luggage in the fore-and-aft direction of the vehicle body based on the weight of the luggage, the thrust of the tilt cylinder before and after the luggage is held in the holding section, and data related to the structure of the loading device. In this configuration, the thrust of the tilt cylinder is detected as the state of the tilt cylinder by detecting the pressure in the rod chamber and the bottom chamber of the tilt cylinder. Therefore, the state of the tilt cylinder before and after the luggage is held in the holding section can be appropriately obtained, so that the center of gravity position of the luggage in the fore-and-aft direction of the vehicle body can be estimated with high accuracy.

The mast is rotatably connected to the front end of the vehicle body via a mast support, and the tilt state detection unit further includes an angle detection unit that detects the tilt angle of the mast, and a distance calculation unit that calculates the distance from the mast support to the tilt cylinder before the load is held in the holding unit and the distance from the mast support to the tilt cylinder after the load is held in the holding unit based on the tilt angle of the mast, and the center of gravity estimation calculation unit may estimate the center of gravity position of the load in the fore-and-aft direction of the vehicle body based on the weight of the load, the thrust of the tilt cylinder before and after the load is held in the holding unit, the distance from the mast support to the tilt cylinder, and data related to the structure of the loading device. In this configuration, the thrust of the tilt cylinder and the distance from the mast support to the tilt cylinder are detected as the state of the tilt cylinder. Therefore, the state of the tilt cylinder before and after the load is held in the holding unit can be obtained more appropriately, so that the center of gravity position of the load in the fore-and-aft direction of the vehicle body can be estimated with higher accuracy.

The center of gravity estimation calculation unit may estimate the position of the center of gravity of the luggage in the fore-and-aft direction of the vehicle body using a formula for determining the combined center of gravity of the mast and the holding unit before the luggage is held by the holding unit and the combined center of gravity of the mast, the holding unit and the luggage after the luggage is held by the holding unit. In this configuration, by using a formula for determining the combined center of gravity of the mast and the holding unit and the combined center of gravity of the mast, the holding unit and the luggage, it is possible to easily estimate the position of the center of gravity of the luggage in the fore-and-aft direction of the vehicle body.

The data regarding the structure of the loading and unloading device may include the weight of the mast and the holding part. In such a configuration, it is not necessary to detect the weight of the mast and the holding part, which can contribute to reducing the number of sensors used.

The present invention makes it possible to reduce the amount of work required while improving the accuracy of estimating the center of gravity position of luggage held in the holding section.

1 is a block diagram showing a configuration of a vehicle control device including a center of gravity estimation device according to an embodiment of the present invention; 2 is a side view showing a forklift as an industrial vehicle equipped with the vehicle control device shown in FIG. 1 . 2 is a flowchart showing the procedure of a tilt thrust calculation process executed by a tilt thrust calculation unit shown in FIG. 1 . 1 is a conceptual diagram showing the thrust of a tilt cylinder, the distance from a mast support to the tilt cylinder, and the position of the center of gravity of a load in the front-rear direction. FIG. FIG. 3 is a cross-sectional view of the tilt cylinder shown in FIG. 2 . 4 is a flowchart showing a procedure of a distance calculation process executed by a distance calculation unit shown in FIG. 1 .

The following describes an embodiment of the present invention in detail with reference to the drawings.

Figure 1 is a block diagram showing the configuration of a vehicle control device equipped with a center of gravity estimation device according to one embodiment of the present invention. In Figure 1, the vehicle control device 1 is mounted on a forklift 2 (Figure 2), which is an industrial vehicle. The vehicle control device 1 is a device that controls the travel of the forklift 2.

As shown in FIG. 2, the forklift 2 is equipped with a traveling device 3 and a loading device 4 that is disposed in front of the traveling device 3 and is used to lift and unload cargo W.

The traveling device 3 has a vehicle body 5, a pair of left and right drive wheels 6 located at the front of the vehicle body 5, a pair of left and right rear wheels 7 located at the rear of the vehicle body 5, a traveling motor 8 that rotates the front wheels 6, a loading motor 9 that drives and rotates a hydraulic pump (not shown) of a hydraulic drive unit 26 (see Figure 1) described below, and a battery 10 that supplies power to the traveling motor 8 and the loading motor 9.

The loading and unloading device 4 has a mast 12 rotatably connected to the front end of the vehicle body 5 via a mast support 11 (see FIG. 4), a pair of left and right forks 14 attached to the mast 12 via lift brackets 13, a lift cylinder 15 for raising and lowering the forks 14, and a tilt cylinder 16 for tilting the mast 12. The forks 14 are one of the attachments that are holding parts for holding luggage W. The lift cylinder 15 and tilt cylinder 16 are driven by a hydraulic drive unit 26 (described later).

The vehicle control device 1 includes a lift cylinder pressure sensor 21, tilt cylinder pressure sensors 22, 23, a tilt angle sensor 24, a display 25, the above-mentioned travel motor 8, a hydraulic drive unit 26, and an electronic control unit 27 (ECU: Electronic Control Unit).

The lift cylinder pressure sensor 21 detects the pressure of the lift cylinder 15. Specifically, the lift cylinder pressure sensor 21 detects the pressure in the bottom chamber of the lift cylinder 15.

The tilt cylinder pressure sensor 22 is a rod pressure detection unit that detects the pressure (rod pressure) in the rod chamber 16a (see FIG. 5) of the tilt cylinder 16. The tilt cylinder pressure sensor 23 is a bottom pressure detection unit that detects the pressure (bottom pressure) in the bottom chamber 16b (see FIG. 5) of the tilt cylinder 16.

The tilt angle sensor 24 is an angle detection unit that detects the tilt angle of the mast 12.

The display 25 displays information such as the tilt angle of the mast 12 and the position of the center of gravity of the luggage W, and also displays a warning regarding the center of gravity of the luggage W.

Although not specifically shown, the hydraulic drive unit 26 includes a hydraulic pump (described above) that supplies hydraulic oil to the lift cylinder 15 and tilt cylinder 16, a lift valve arranged between the hydraulic pump and the lift cylinder 15, and a tilt valve arranged between the hydraulic pump and the tilt cylinder 16.

The electronic control unit 27 is composed of a CPU, RAM, ROM, an input/output interface, etc. The electronic control unit 27 has a memory section 31, a luggage weight calculation section 32, a tilt thrust calculation section 33, a distance calculation section 34, a center of gravity estimation calculation section 35, and a control section 36.

The memory unit 31 stores data regarding the structure of the loading and unloading device 4, including the lift cylinder 15 and tilt cylinder 16, and a calculation formula for estimating the center of gravity of the cargo W. The structure of the lift cylinder 15 includes the dimensions, weight, and position of the lift cylinder 15. The structure of the tilt cylinder 16 includes the dimensions, weight, position, and attitude of the tilt cylinder 16. Other structures of the loading and unloading device 4 include the dimensions, positions, and weights of the mast 12 and forks 14, etc.

The luggage weight calculation unit 32 calculates the weight of the luggage W held by the forks 14 based on the pressure of the lift cylinder 15 detected by the lift cylinder pressure sensor 21. The luggage weight calculation unit 32 cooperates with the lift cylinder pressure sensor 21 to form a weight detection unit that detects the weight of the luggage W held by the forks 14.

The tilt thrust calculation unit 33 calculates the thrust of the tilt cylinder 16 before the luggage W is held by the forks 14 and the thrust of the tilt cylinder 16 after the luggage W is held by the forks 14 based on the pressure in the rod chamber 16a of the tilt cylinder 16 detected by the tilt cylinder pressure sensor 22, the pressure in the bottom chamber 16b of the tilt cylinder 16 detected by the tilt cylinder pressure sensor 23, and data regarding the structure of the tilt cylinder 16 stored in the memory unit 31.

Figure 3 is a flowchart showing the steps of the tilt thrust calculation process executed by the tilt thrust calculation unit 33.

In FIG. 3, the tilt thrust calculation unit 33 first acquires the detection values of the tilt cylinder pressure sensors 22, 23 before the luggage W is held by the forks 14 (step S101). Then, the tilt thrust calculation unit 33 calculates the thrust of the tilt cylinder 16 before the luggage W is held by the forks 14 based on the detection values of the tilt cylinder pressure sensors 22, 23 and the dimensions of the tilt cylinder 16 (step S102).

Specifically, the tilt thrust calculation unit 33 calculates the thrust Ftilt1 of the tilt cylinder 16 before the baggage W is held by the forks 14 using the following formula: The thrust (Ftilt) of the tilt cylinder 16 is a load applied in the axial direction of the tilt cylinder 16, as shown in FIG.
Ftilt1＝Srod×Prod1−Sbtm×Pbtm1

5, Sbtm is the cross-sectional area of the bottom chamber 16b of the tilt cylinder 16. Srod is the cross-sectional area of the rod chamber 16a of the tilt cylinder 16 and is expressed by the following formula. Rrod is the diameter of the piston rod 16c of the tilt cylinder 16. Sbtm and Srod are stored in the memory unit 31.
Srod = Sbtm - Rrod

Prod1 is the pressure in the rod chamber 16a of the tilt cylinder 16 before the luggage W is held by the forks 14. Pbtm1 is the pressure in the bottom chamber 16b of the tilt cylinder 16 before the luggage W is held by the forks 14.

Then, the tilt thrust calculation unit 33 acquires the detection values of the tilt cylinder pressure sensors 22, 23 after the luggage W is held by the forks 14 (step S103). Then, the tilt thrust calculation unit 33 calculates the thrust of the tilt cylinder 16 after the luggage W is held by the forks 14 based on the detection values of the tilt cylinder pressure sensors 22, 23 and the dimensions of the tilt cylinder 16 (step S104).

Specifically, the tilt thrust calculation unit 33 calculates the thrust Ftilt2 of the tilt cylinder 16 after the baggage W is held by the forks 14 using the following formula.
Ftilt2＝Srod×Prod2−Sbtm×Pbtm2

Prod2 is the pressure in the rod chamber 16a of the tilt cylinder 16 after the luggage W is held by the forks 14. Pbtm2 is the pressure in the bottom chamber 16b of the tilt cylinder 16 after the luggage W is held by the forks 14.

Next, the tilt thrust calculation unit 33 outputs calculation data of the thrust Ftilt1 of the tilt cylinder 16 before the luggage W is held by the forks 14 and calculation data of the thrust Ftilt2 of the tilt cylinder 16 after the luggage W is held by the forks 14 to the center of gravity estimation calculation unit 35 (step S105).

Note that the calculation of the thrust force Ftilt1 of the tilt cylinder 16 before the fork 14 holds the luggage W (steps S101 and S102) does not necessarily have to be performed every time, but may be performed only at appropriate times. In this case, the calculated value of Ftilt1 is stored in the memory unit 31.

The distance calculation unit 34 calculates the distance from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14 and the distance from the mast support 11 to the tilt cylinder 16 after the luggage W is held by the forks 14 based on the tilt angle of the mast 12 detected by the tilt angle sensor 24 and data regarding the structure of the tilt cylinder 16 stored in the memory unit 31.

Figure 6 is a flowchart showing the steps of the distance calculation process executed by the distance calculation unit 34.

In FIG. 6, the distance calculation unit 34 first acquires the detection value of the tilt angle sensor 24 before the luggage W is held by the forks 14 (step S111). Then, the distance calculation unit 34 calculates the distance Ltilt1 from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14 based on the detection value of the tilt angle sensor 24 and the position and attitude of the tilt cylinder 16 (step S112).

The distance (Ltilt) from the mast support 11 to the tilt cylinder 16 is the distance from the mast support 11 to the intersection of a line passing through the mast support 11 and perpendicular to the axis of the tilt cylinder 16 with the axis of the tilt cylinder 16, as shown in Figure 4.

Then, the distance calculation unit 34 acquires the detection value of the tilt angle sensor 24 after the luggage W is held by the forks 14 (step S113). Then, the distance calculation unit 34 calculates the distance Ltilt2 from the mast support 11 to the tilt cylinder 16 after the luggage W is held by the forks 14 based on the detection value of the tilt angle sensor 24 and the position and attitude of the tilt cylinder 16 (step S114).

The distance calculation unit 34 then outputs to the center of gravity estimation calculation unit 35 the calculated data of the distance Ltilt1 from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14, and the calculated data of the distance Ltilt2 from the mast support 11 to the tilt cylinder 16 after the luggage W is held by the forks 14 (step S115).

As with the calculation of the thrust Ftilt1 of the tilt cylinder 16 described above, the calculation of the distance Ltilt1 from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14 (steps S111 and S112) does not necessarily have to be performed every time, but may be performed only at appropriate times. In this case, the calculated value of Ltilt1 is also stored in the memory unit 31.

The tilt cylinder pressure sensors 22, 23, the tilt angle sensor 24, the tilt thrust calculation unit 33, and the distance calculation unit 34 constitute a tilt state detection unit that detects the state of the tilt cylinder 16 before the luggage W is held by the forks 14 and the state of the tilt cylinder 16 after the luggage W is held by the forks 14.

The center of gravity estimation calculation unit 35 estimates the position of the center of gravity of the luggage W in the fore-and-aft direction of the vehicle body 5 based on the weight of the luggage W calculated by the luggage weight calculation unit 32, the thrust of the tilt cylinder 16 before and after the luggage W is held by the forks 14 calculated by the tilt thrust calculation unit 33, the distance from the mast support 11 to the tilt cylinder 16 before and after the luggage W is held by the forks 14 calculated by the distance calculation unit 34, and data related to the structure of the loading device 4 stored in the memory unit 31.

Specifically, the center of gravity estimation calculation unit 35 calculates the center of gravity position GCx_w of the luggage W in the fore-and-aft direction (X direction) of the vehicle body 5 by the following formula. The center of gravity in the fore-and-aft direction of the vehicle body 5 is simply referred to as the fore-and-aft center of gravity. Here, the position of the center of gravity GCx_w of the luggage W in the fore-and-aft direction is a position with the mast support 11 as the origin, as shown in FIG.
GCx_mast_att＝(Mmast×GCx_mast＋Matt×GCx_att)/(Mmast＋Matt) …(A)
GCx_mast_att＝(Ftilt1×Ltilt1)/(Mmast＋Matt) …(B)
GCx_mast_att_w＝((Mmast＋Matt)×GCx_mast_att＋Mw×GCx_w)/(Mmast＋Matt＋Mw) …(C)
GCx_mast_att_w＝(Ftilt2×Ltilt2)/(Mmast＋Matt＋Mw) …(D)
Mmast×GCx_mast＋Matt×GCx_att＝(Mmast＋Matt)×GCx_mast_att …(E)

GCx_mast_att is the combined center of gravity in the fore-and-aft direction of the mast 12 and the forks 14 before the luggage W is held by the forks 14. GCx_mast_att_w is the combined center of gravity in the fore-and-aft direction of the mast 12, the forks 14, and the luggage W after the luggage W is held by the forks 14. GCx_mast is the center of gravity in the fore-and-aft direction of the mast 12 alone. GCx_att is the center of gravity in the fore-and-aft direction of the forks 14 alone.

Mmast is the weight of the mast 12 and is stored in the memory unit 31. Matt is the weight of the forks 14 and is stored in the memory unit 31. Mw is the weight of the luggage W calculated by the luggage weight calculation unit 32.

The above formulas (A) and (B) are used to calculate the combined center of gravity of the mast 12 and the forks 14 before the luggage W is held by the forks 14. The above formulas (C) and (D) are used to calculate the combined center of gravity of the mast 12, the forks 14, and the luggage W after the luggage W is held by the forks 14. The position of the center of gravity GCx_w in the fore-and-aft direction of the luggage W is calculated using the above formulas (A) to (E).

Here, the lift cylinder pressure sensor 21, the tilt cylinder pressure sensors 22, 23, the tilt angle sensor 24, the memory unit 31 of the electronic control unit 27, the luggage weight calculation unit 32, the tilt thrust calculation unit 33, the distance calculation unit 34, and the center of gravity estimation calculation unit 35 constitute the center of gravity estimation device 20 of this embodiment.

The control unit 36 causes the display 25 to display the position of the center of gravity of the luggage W in the forward/backward direction, and also causes the display 25 to display a warning when the position of the center of gravity of the luggage W in the forward/backward direction is not within a predetermined center of gravity tolerance range.

The control unit 36 also controls the travel motor 8 and the hydraulic drive unit 26 to restrict travel and loading and unloading when the position of the center of gravity of the luggage W in the fore-and-aft direction is not within the allowable center of gravity range. For example, the control unit 36 controls the travel motor 8 to restrict the travel acceleration during acceleration and the travel deceleration during deceleration. The control unit 36 also controls the hydraulic drive unit 26 to restrict the acceleration and deceleration during lifting and lowering of the luggage W and the acceleration and deceleration during forward and backward tilting of the mast 12. The control unit 36 may also control the hydraulic drive unit 26 to stop the lifting of the forks 14, or control the hydraulic drive unit 26 to stop the forward tilting of the mast 12, as restrictions on loading and unloading.

As described above, in this embodiment, the weight of the luggage W held by the forks 14 is detected, and the state of the tilt cylinder 16 before the luggage W is held by the forks 14 and the state of the tilt cylinder 16 after the luggage W is held by the forks 14 are detected. Then, based on the weight of the luggage W, the state of the tilt cylinder 16 before and after the luggage W is held by the forks 14, and data related to the structure of the loading device 4, an estimation calculation is performed for the center of gravity position of the luggage W in the front-rear direction of the vehicle body 5. In this way, the center of gravity position of the luggage W held by the forks 14 is estimated without acquiring the centers of gravity of the mast 12 and the forks 14. This reduces the labor required for estimating the center of gravity, while improving the estimation accuracy of the center of gravity position of the luggage W held by the forks 14. In addition, it is no longer necessary to acquire the centers of gravity of the mast 12 and the forks 14 in advance for each product of the mast 12 and the forks 14, improving versatility.

In addition, in this embodiment, the thrust of the tilt cylinder 16 is detected as the state of the tilt cylinder 16 by detecting the pressure in the rod chamber 16a and the bottom chamber 16b of the tilt cylinder 16. Therefore, the state of the tilt cylinder 16 before and after the luggage W is held by the forks 14 can be properly obtained, so the position of the center of gravity of the luggage W in the fore-and-aft direction of the vehicle body 5 can be estimated with high accuracy.

In addition, in this embodiment, the state of the tilt cylinder 16 is detected as the thrust of the tilt cylinder 16 and the distance from the mast support 11 to the tilt cylinder 16. Therefore, the state of the tilt cylinder 16 before and after the luggage W is held by the forks 14 can be obtained more appropriately, so that the position of the center of gravity of the luggage W in the fore-and-aft direction of the vehicle body 5 can be estimated with higher accuracy.

In addition, in this embodiment, by using a formula for determining the combined center of gravity of the mast 12 and the forks 14 and the combined center of gravity of the mast 12, the forks 14, and the luggage W, it is possible to easily estimate the position of the center of gravity of the luggage W in the fore-and-aft direction of the vehicle body 5.

In addition, in this embodiment, by storing the weights of the mast 12 and forks 14 in the memory unit 31, it is not necessary to detect the weights of the mast 12 and forks 14, which contributes to reducing the number of sensors used.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the distance from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14 and the distance from the mast support 11 to the tilt cylinder 16 after the luggage W is held by the forks 14 are calculated, but the present invention is not particularly limited to such an embodiment. For example, if there is little change in the distance from the mast support 11 to the tilt cylinder 16 before and after the luggage W is held by the forks 14, the distance from the mast support 11 to the tilt cylinder 16 before the luggage W is held by the forks 14 may be calculated, and the calculated data of the distance may also be used as the distance from the mast support 11 to the tilt cylinder 16 after the luggage W is held by the forks 14.

In the above embodiment, the pressure in the rod chamber 16a and bottom chamber 16b of the tilt cylinder 16 is detected to calculate the thrust of the tilt cylinder 16 before the luggage W is held by the forks 14 and the thrust of the tilt cylinder 16 after the luggage W is held by the forks 14, but this is not limited to a particular form. For example, a strain gauge, a bolt axial force meter, or the like may be used to detect the state of the tilt cylinder 16 before the luggage W is held by the forks 14 and the state of the tilt cylinder 16 after the luggage W is held by the forks 14.

In the above embodiment, the pressure of the lift cylinder 15 is detected to calculate the weight of the luggage M held by the forks 14, but this is not limited to a particular form, and the weight of the luggage M held by the forks 14 may be calculated using a strain gauge or the like. Also, the driver may measure the weight of the luggage M in advance and input the weight data of the luggage M using an input device or the like.

In addition, the center of gravity estimation device 20 in the above embodiment is applied to a battery-powered forklift 2 in which the front wheels 6, which are the drive wheels, are rotated by a travel motor 8, but the present invention can also be applied to an engine-powered forklift in which the drive wheels are rotated by an engine.

In addition, the center of gravity estimation device 20 in the above embodiment is mounted on a forklift 2 equipped with forks 14 for holding cargo W, but the present invention can also be applied to industrial vehicles such as forklifts equipped with other attachments for holding cargo W.

2...Forklift (industrial vehicle), 4...Loading device, 5...Vehicle body, 11...Mast support, 12...Mast, 14...Fork (holding section), 15...Lift cylinder, 16...Tilt cylinder, 16a...Rod chamber, 16b...Bottom chamber, 20...Center of gravity estimation device, 21...Lift cylinder pressure sensor (weight detection section), 22...Tilt cylinder pressure sensor (rod pressure detection section, tilt state detection unit), 23...Tilt cylinder pressure sensor (bottom pressure detection section, tilt state detection unit), 24...Tilt angle sensor (angle detection section, tilt state detection unit), 31...Memory section, 32...Luggage weight calculation section (weight detection section), 33...Tilt thrust calculation section (tilt state detection unit), 34...Distance calculation section (tilt state detection unit), 35...Center of gravity estimation calculation section, W...Luggage.

Claims (6)

2. A center of gravity estimation device for an industrial vehicle equipped with a loading device having a holding part attached to a mast and holding a load, a lift cylinder for raising and lowering said holding part, and a tilt cylinder for tilting said mast,
A storage unit that stores data related to the structure of the loading device;
a weight detection unit that detects the weight of the baggage held by the holding unit;
a tilt state detection unit that detects a state of the tilt cylinder before the luggage is held by the holding portion and a state of the tilt cylinder after the luggage is held by the holding portion;
a center of gravity estimation calculation unit that estimates and calculates a center of gravity position of the load in a front-rear direction of a body of the industrial vehicle based on a weight of the load, a state of the tilt cylinder before and after the load is held by the holding unit, and data related to a structure of the loading device ,
the tilt state detection unit has a rod pressure detection unit which detects the pressure in a rod chamber of the tilt cylinder, a bottom pressure detection unit which detects the pressure in a bottom chamber of the tilt cylinder, and a tilt thrust calculation unit which calculates the thrust of the tilt cylinder before the luggage is held in the holding section and the thrust of the tilt cylinder after the luggage is held in the holding section based on the pressure in the rod chamber of the tilt cylinder and the pressure in the bottom chamber of the tilt cylinder,
The center of gravity estimation calculation unit is a center of gravity estimation device for an industrial vehicle that estimates and calculates the position of the center of gravity of the cargo in the fore-and-aft direction of the vehicle body based on the weight of the cargo, the thrust of the tilt cylinder before and after the cargo is held in the holding unit, and data regarding the structure of the loading and unloading device. The mast is rotatably connected to a front end portion of the vehicle body via a mast support,
the tilt state detection unit further includes an angle detection unit that detects a tilt angle of the mast, and a distance calculation unit that calculates, based on the tilt angle of the mast, a distance from the mast support to the tilt cylinder before the load is held by the holding unit and a distance from the mast support to the tilt cylinder after the load is held by the holding unit,
2. The center of gravity estimation device for an industrial vehicle as described in claim 1, wherein the center of gravity estimation calculation unit estimates and calculates the position of the center of gravity of the cargo in the fore-and-aft direction of the vehicle body based on the weight of the cargo, the thrust of the tilt cylinder before and after the cargo is held by the holding unit and the distance from the mast support to the tilt cylinder, and data regarding the structure of the loading and unloading device. 3. A center of gravity estimation device for an industrial vehicle as described in claim 1 or 2, wherein the center of gravity estimation calculation unit estimates the position of the center of gravity of the luggage in the fore-and-aft direction of the vehicle body using a formula for determining the combined center of gravity of the mast and the holding part before the luggage is held in the holding part and the combined center of gravity of the mast, the holding part and the luggage after the luggage is held in the holding part. 4. The center of gravity estimation device for an industrial vehicle according to claim 3 , wherein the data relating to the structure of the loading device includes weights of the mast and the holding portion. 2. A center of gravity estimation device for an industrial vehicle equipped with a loading device having a holding part attached to a mast and holding a load, a lift cylinder for raising and lowering said holding part, and a tilt cylinder for tilting said mast,
A storage unit that stores data related to the structure of the loading device;
a weight detection unit that detects the weight of the baggage held by the holding unit;
a tilt state detection unit that detects a state of the tilt cylinder before the luggage is held by the holding portion and a state of the tilt cylinder after the luggage is held by the holding portion;
a center of gravity estimation calculation unit that estimates and calculates a center of gravity position of the load in a front-rear direction of a body of the industrial vehicle based on a weight of the load, a state of the tilt cylinder before and after the load is held by the holding unit, and data related to a structure of the loading device,
The center of gravity estimation calculation unit is an industrial vehicle center of gravity estimation device that estimates and calculates the position of the center of gravity of the cargo in the fore-and-aft direction of the vehicle body using a formula to determine the combined center of gravity of the mast and the holding part before the cargo is held in the holding part and the combined center of gravity of the mast, the holding part and the cargo after the cargo is held in the holding part. 6. The center of gravity estimation device for an industrial vehicle according to claim 5 , wherein the data relating to the structure of the loading device includes weights of the mast and the holding portion.

Images