阅读说明：本技术 无人搬运车 (Unmanned carrying vehicle ) 是由 西泽康裕 上野俊幸 松下祐也 于 2018-04-27 设计创作，主要内容包括：本发明提供一种对台车(10)进行搬运的无人搬运车(20),无人搬运车(20)设有：流体压力缸(22),其向台车(10)的地面作用向上的上推力且在上下方向上伸缩自如；流体压力供给装置(70),其对于流体压力缸(22)供给流体；压力调整机构(50),其调整从流体压力供给装置(70)向流体压力缸(22)供给的流体的流体压力；控制基板(40),其向压力调整机构(50)输出流体压力的指令值；以及压力传感器(100),其检测向流体压力缸(22)供给的流体的流体压力,控制基板(40)计算由压力传感器(100)检测出的流体压力的微分值,基于计算出的微分值的图案来推断台车开始悬浮的时刻,并对由压力传感器(100)在推断出的时刻下检测出的流体压力乘以小于1的系数,从而计算指令值。(The present invention provides an automated guided vehicle (20) for conveying a trolley (10), wherein the automated guided vehicle (20) is provided with: a fluid pressure cylinder (22) which exerts upward thrust on the floor surface of the carriage (10) and is freely extendable and retractable in the vertical direction; a fluid pressure supply device (70) that supplies fluid to the fluid pressure cylinder (22); a pressure adjustment mechanism (50) that adjusts the fluid pressure of the fluid supplied from the fluid pressure supply device (70) to the fluid pressure cylinder (22); a control substrate (40) that outputs a command value for the fluid pressure to the pressure adjustment mechanism (50); and a pressure sensor (100) that detects the fluid pressure of the fluid supplied to the fluid pressure cylinder (22), wherein the control board (40) calculates a differential value of the fluid pressure detected by the pressure sensor (100), estimates the time at which the carriage starts to float based on a pattern of the calculated differential value, and calculates a command value by multiplying the fluid pressure detected by the pressure sensor (100) at the estimated time by a coefficient smaller than 1.)

1. An automated guided vehicle that travels into a predetermined space formed between a bottom surface of a vehicle and a floor surface to transport the vehicle, the automated guided vehicle comprising:

A fluid pressure cylinder which makes an upward thrust act on the ground of the trolley and can freely extend and retract in the vertical direction;

A fluid pressure supply device that supplies fluid to the fluid pressure cylinder;

A pressure adjustment mechanism that adjusts a fluid pressure of the fluid supplied from the fluid pressure supply device to the fluid pressure cylinder;

A control substrate that outputs a command value of fluid pressure to the pressure adjustment mechanism; and

a pressure sensor that detects a fluid pressure of the fluid supplied to the fluid pressure cylinder,

The control substrate is provided with:

A differential circuit that calculates a differential value of the fluid pressure detected by the pressure sensor;

An estimation circuit that estimates a time when the vehicle starts to float, based on a pattern of differential values calculated by the differential circuit; and

And a coefficient multiplication circuit configured to multiply a fluid pressure detected by the pressure sensor at the time estimated by the estimation circuit by a coefficient smaller than 1 to calculate the command value.

2. The automated guided vehicle according to claim 1,

The fluid pressure cylinder is configured such that a piston is inserted into a cylinder body so as to be movable up and down, a receiving plate that contacts a bottom surface of the carriage is provided at an upper end of a piston rod connected to the piston, and a proximity switch that is turned on when the proximity switch approaches a ground surface of the carriage by a predetermined amount or more is provided on the receiving plate.

The estimation circuit estimates a time when the vehicle starts to float, when the differential value calculated by the differential circuit increases to a first predetermined value or more and then decreases to a second predetermined value or less in a state where the proximity switch is turned on.

3. The automated guided vehicle according to claim 1,

The estimation circuit estimates the time when the carriage starts to float, after a predetermined time has elapsed since the fluid pressure cylinder starts to extend, the differential value calculated by the differential circuit has increased to a first predetermined value or more and then has decreased to a second predetermined value or less.

4. The automated guided vehicle according to claim 1,

The estimation circuit estimates a time when the vehicle starts to float, when the differential value calculated by the differential circuit becomes substantially 0.

5. the automated guided vehicle according to claim 1,

When the number of the fluid pressure cylinders is plural, the pressure adjusting mechanism and the pressure sensor are provided for each of the fluid pressure cylinders,

The coefficient multiplication circuit outputs a command value corresponding to the pressure detected by each of the pressure sensors to each of the pressure adjustment mechanisms.

Technical Field

The present invention relates to an automated guided vehicle. More particularly, the present invention relates to an automated guided vehicle capable of stably conveying a carriage.

Background

patent document 1 discloses a traction method: in order to transport parts to an assembly line of an assembly plant, an automated guided Vehicle (hereinafter abbreviated as AGV) that travels along a Guide path laid on a plant floor is pulled by integrating the automated guided Vehicle and a trolley by pin coupling. Namely, the traction method is as follows: a combination groove is provided on the bottom surface of the trolley, and a combination pin is inserted into the combination groove of the trolley from the AGV in a state where the AGV is inserted under the bottom plate of the trolley, thereby integrating the combination pin. Patent documents 2 and 3 also disclose the same technique.

Patent document 4 discloses the following technique: and (4) enabling the AGV to drill into the lower part of the trolley, and completely lifting the trolley through a lifting device equipped with the AGV. The lifted cart becomes the wheel off the ground.

Disclosure of Invention

technical problem to be solved by the invention

As in patent documents 1, 2, and 3, in the traction system, a bottom surface of the carriage is modified to provide a combination groove, which leads to an increase in cost. The method is particularly remarkable in factories and logistics centers which need to be modified by a large number of trolleys. In addition, in the case of the traction system, the main body of the AGV needs to be heavy in order to prevent the driving wheels from idling.

As in patent document 4, in the technique of completely lifting the carriage by the lifting device provided in the AGV, since the wheels of the carriage float off the ground, there is a risk that the load in the carriage falls down when the load is unbalanced.

In this regard, the inventors of the present invention have made a related application (Japanese patent application 2015-255945).

In this related application, if the dolly is completely lifted up to about 20mm without turning on the upper limit switch of the cylinder, the load balance is not clear.

Therefore, if the cylinder is not operated to level the receiving plate in contact with the carriage, the carriage may be greatly inclined or the load of the carriage may collapse.

in addition, since it is necessary to lift the cylinder to the maximum stroke even if there is an unbalanced load, it is necessary to select the maximum load applied to an assumed one of the cylinders and the pressure to be supplied to the cylinder that can lift the maximum load.

Technical solution for solving technical problem

An automated guided vehicle according to a first aspect of the present invention to solve the above problems is an automated guided vehicle that travels a carriage by entering a predetermined space formed between a bottom surface of the carriage and a floor surface, the automated guided vehicle including: a fluid pressure cylinder which is extendable and retractable in a vertical direction in which an upward thrust is applied to a ground surface of the carriage; a fluid pressure supply device that supplies fluid to the fluid pressure cylinder; a pressure adjustment mechanism that adjusts a fluid pressure of the fluid supplied from the fluid pressure supply device to the fluid pressure cylinder; a control substrate that outputs a command value of fluid pressure to the pressure adjustment mechanism; and a pressure sensor that detects a fluid pressure of the fluid supplied to the fluid pressure cylinder, the control board including: a differential circuit that calculates a differential value of the fluid pressure detected by the pressure sensor; an estimation circuit that estimates a time when the vehicle starts to float, based on a pattern of differential values calculated by the differential circuit; and a coefficient multiplication circuit that multiplies the fluid pressure detected by the pressure sensor at the timing inferred by the inference circuit by a coefficient smaller than 1 to calculate the command value.

According to a first aspect of the present invention, in an automated guided vehicle according to a second aspect of the present invention to solve the above-described problems, the fluid pressure cylinder is configured such that a piston is inserted into a cylinder main body so as to be movable up and down, a receiving plate that contacts a bottom surface of the carriage is provided at an upper end of a piston rod connected to the piston, a proximity switch that is turned on when the proximity switch approaches a ground surface of the carriage by a predetermined value or more is provided at the receiving plate, and the estimation circuit estimates a timing at which the carriage starts to float, when the estimation circuit decreases to a second predetermined value or less after the differential value calculated by the differential circuit increases to the first predetermined value or more in a state in which the proximity switch is turned on.

According to the first aspect, in the automated guided vehicle according to the third aspect of the present invention, in order to solve the above-described problems, the estimation circuit estimates the time at which the vehicle starts to float, as the time at which the vehicle starts to float, after the fluid pressure cylinder starts to extend and a predetermined time elapses, the differential value calculated by the differential circuit increases to a first predetermined value or more and then decreases to a second predetermined value or less.

According to the first aspect, in the automated guided vehicle according to the fourth aspect of the present invention, in order to solve the above-described problem, the estimation circuit estimates the time at which the vehicle starts to float, when the differential value calculated by the differential circuit becomes substantially 0.

According to a fifth aspect of the present invention, in the automated guided vehicle according to the first aspect, in which the fluid pressure cylinders are provided in plurality, the pressure adjusting means and the pressure sensors are provided for the respective fluid pressure cylinders, and the coefficient multiplying circuit outputs instruction values corresponding to pressures detected by the respective pressure sensors to the respective pressure adjusting means.

Effects of the invention

in the automated guided vehicle according to the present invention, the fluid pressure of the fluid supplied to the fluid cylinder is detected by the pressure sensor, the differential value of the detected fluid pressure is calculated by the differential circuit, the timing at which the vehicle starts to float is estimated by the estimation circuit based on the pattern of the differential value calculated by the differential circuit, and the fluid pressure detected by the pressure sensor at the timing estimated by the estimation circuit is multiplied by a coefficient smaller than 1 by the coefficient multiplication circuit to be output as a command value from the control board to the pressure adjustment mechanism.

Drawings

Fig. 1 is a side view of an automated guided vehicle according to a first embodiment of the present invention.

Fig. 2 is a plan view of the automated guided vehicle according to the first embodiment of the present invention.

Fig. 3 is a diagram of a pressure adjustment system of the automated guided vehicle according to the first embodiment of the present invention.

Fig. 4 is a schematic view of an electric-gas pressure regulating valve used for the automated guided vehicle according to the first embodiment of the present invention.

Fig. 5 is a plan view of an automated guided vehicle according to a second embodiment of the present invention.

Fig. 6 is a graph showing the pressure of the cylinder superimposed on the trolley elevation.

Detailed Description

The present invention will be described in detail below with reference to embodiments shown in the drawings.