CN113697721B - Method and device for judging unreeling of fork type AGV hoisting system - Google Patents

Method and device for judging unreeling of fork type AGV hoisting system Download PDF

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Publication number
CN113697721B
CN113697721B CN202010436010.5A CN202010436010A CN113697721B CN 113697721 B CN113697721 B CN 113697721B CN 202010436010 A CN202010436010 A CN 202010436010A CN 113697721 B CN113697721 B CN 113697721B
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motor
load
state information
lifting
fork type
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CN113697721A (en
Inventor
陈清
黄荣荣
侯典清
朱平
陈静思
许超
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Linde China Forklift Truck Corp Ltd
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Linde China Forklift Truck Corp Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/063—Automatically guided
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F17/00—Safety devices, e.g. for limiting or indicating lifting force
    • B66F17/003—Safety devices, e.g. for limiting or indicating lifting force for fork-lift trucks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/0755—Position control; Position detectors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/24—Electrical devices or systems

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Forklifts And Lifting Vehicles (AREA)

Abstract

A method and a device for judging the unreeling of a fork type AGV hoisting system acquire state information of a load and state information of a motor, and judge whether the unreeling is carried out according to the state information of the motor and the state information of the load by combining a preset threshold value. The invention can make judgment in early stage of loose coil generation, avoid the continuous occurrence and deterioration of loose coil, and can judge the loose coil caused by the barrier in the descending process of the fork.

Description

Method and device for judging unreeling of fork type AGV hoisting system
Technical Field
The invention relates to the field of forklifts, in particular to a method and a device for judging the unreeling of a fork type AGV hoisting lifting system.
Background
And the hoisting system of the fork AGV realizes the lifting movement of the fork by using a hoisting mechanism. One end of a common hoisting mechanism such as a steel wire rope, a flat belt and the like is fixed on the winding drum and can be retracted and released along with the rotation of the winding drum; the other end is fixed on the fork frame. The control unit of AGV drives hoist motor to rotate, drives the reel rotation to realize the elevating movement of fork.
Currently, lifting systems employing hoisting mechanisms may suffer from unreeling problems. The reasons for this phenomenon are generally: 1. when the fork is lowered to the lowest position, the winch motor continues to rotate; 2. the fork can not continue to descend normally when being blocked by an obstacle in the descending process. At this time, the wire rope, the flat belt and the like between the fork and the winding drum lose due tension to be loosened, and further, the wire rope, the flat belt and the like reserved on the winding drum are loosened to generate potential safety hazards.
The common judging method is to install a proximity switch on the winding drum, wherein the detection position of the proximity switch is generally a critical position requiring the least number of turns to be reserved, such as a steel wire rope, a flat belt and the like. Whether the wire rope, the flat belt and the like reserved on the winding drum are paid out or not is judged through a proximity switch feedback signal, so that the judgment of unreeling is realized. This method can determine the unwinding caused by the first cause but cannot make a timely determination of the second cause.
Disclosure of Invention
The invention mainly aims to overcome the defects in the prior art, and provides a method and a device for judging the loose coil of a fork type AGV hoisting lifting system, which are more accurate in judgment and can effectively avoid continuous occurrence and deterioration of the loose coil.
The invention adopts the following technical scheme:
a method for judging the unreeling of a fork type AGV hoisting system is characterized in that: and acquiring state information of the load and state information of the motor, and judging whether to unwind or not according to the state information of the motor and the state information of the load and by combining a preset threshold value.
Preferably, the state information of the motor is the rotation speed of the motor, and the state information of the load is the height of the load; and in a certain time window, calculating a first lifting speed according to the height of the load, calculating a second lifting speed according to the rotating speed of the motor, and if the difference value between the second lifting speed and the first lifting speed is greater than a preset threshold value, winding and unwinding.
Preferably, the first lifting speed calculating method is as follows: in the time window, calculating the lifting speed of each sampling interval according to the load height, and filtering to remove the error value with overlarge deviation; and calculating an average value of the plurality of filtered lifting speeds to obtain a first lifting speed.
Preferably, the second lifting speed calculating method is as follows: and in the time window, filtering the motor rotating speed to remove an error value with overlarge deviation, calculating the lifting speed of each sampling interval according to the motor rotating speed, and calculating an average value of a plurality of lifting speeds to obtain a second lifting speed.
Preferably, the state information of the motor is steering of the motor, the state information of the load is height of the load, and if the motor rotates in a direction of driving the load to descend within a certain time interval, and the height difference of the load is smaller than a preset threshold value, the winding is unwound.
Preferably, the state information of the motor is steering of the motor, and the state information of the load is an actual load; if the motor rotates towards the descending direction in the current state and the actual load is smaller than the preset threshold value, the winding is unwound.
Preferably, the actual load is related to the current of the motor, and if the motor rotates in the descending direction in the current state and the current of the motor is less than a preset threshold value, the winding is unwound.
A fork formula AGV hoist hoisting system's loose roll judgement device, its characterized in that: the method for judging the unreeling of the fork type AGV hoisting system comprises the following steps of
The first detection unit acquires state information of the load;
the second detection unit is used for acquiring state information of the motor;
and the control unit is used for processing according to the state information of the load and the state information of the motor and judging whether the coil is unwound or not by combining a preset threshold value.
The state information of the load comprises the height or the actual load of the load, and the first detection unit is a height sensor or a current sensor.
The state information of the motor comprises the rotating speed of the motor or the steering direction of the motor, and the second detection unit is a motor rotating speed sensor or a motor encoder.
As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:
1. according to the method and the device, the state information of the load and the state information of the motor are obtained, whether the loose coil is released or not is judged according to the state information of the motor and the state information of the load in combination with the preset threshold value, the judgment can be made in the early stage of releasing the coil, and the judgment is not needed until the reserved coil number is reduced to the critical value. Avoid the loose coil to continue to take place and worsen, in addition, can also judge the fork and descend the in-process because of the barrier stops the loose coil that leads to improved the security of AGV automation mechanized operation, thereby judge in time that the loose coil takes place to reduce the shut down maintenance time that the loose coil arouses, improved efficiency.
2. According to the method and the device, the state information of the load comprises the height or the actual load of the load, the state information of the motor comprises the rotating speed of the motor or the steering of the motor, the unreeling is judged through specific information combination, the judging mode is various, and the principle is simple and easy to realize.
3. The device provided by the invention has the advantages that the first detection unit is a height sensor or a current sensor, the second detection unit is a motor rotating speed sensor or a motor encoder, the structure of the original lifting system is changed little, the preset threshold value can be set according to the requirement, and the popularization is convenient.
Drawings
FIG. 1 is a main flow chart of the present invention;
FIG. 2 is a flow chart of an embodiment of the present invention;
FIG. 3 is a schematic diagram of a stay wire encoder installation;
FIG. 4 is a schematic view of a laser rangefinder installation;
FIG. 5 is a first lifting speed calculation flow chart;
FIG. 6 is a second lifting speed calculation flow chart;
FIG. 7 is a flow chart of an embodiment;
FIG. 8 is a flow chart of an embodiment.
The invention is further described in detail below with reference to the drawings and the specific examples.
Detailed Description
The invention is further described below by means of specific embodiments.
Referring to fig. 1, a method for determining whether a pallet fork type AGV hoist lifting system is unwound is provided, in which state information of a motor and state information of a load are acquired, and whether the pallet fork type AGV hoist lifting system is unwound is determined according to the state information of the motor and the state information of the load in combination with a preset threshold.
Correspondingly, the invention provides a coil loosening judging device of a fork type AGV hoisting and lifting system, which comprises
The first detection unit is used for acquiring state information of the load; the second detection unit is used for acquiring state information of the motor; and the control unit is used for processing according to the state information of the motor and the state information of the load and judging whether the coil is unwound or not by combining with a preset threshold value.
In the invention, the state information of the load comprises the height of the load or the actual load, the first detection unit is a height sensor or a current sensor, and the like, and the actual load is related to the motor torque. The state information of the motor comprises the rotating speed of the motor or the steering direction of the motor, and the second detection unit is a motor rotating speed sensor or a motor encoder and the like. According to different information, the invention can adopt different methods to judge the unreeling condition.
Example 1
Referring to fig. 2, a method for judging whether a pallet fork type AGV hoisting system is unreeled is provided, state information of a motor and state information of a load are obtained, and whether the pallet fork type AGV hoisting system is unreeled or not is judged according to the state information of the motor and the state information of the load and by combining a preset threshold value. The state information of the motor is the rotating speed of the motor, and the state information of the load is the height of the load; and in a certain time window, calculating a first lifting speed according to the height of the load, calculating a second lifting speed according to the rotating speed of the motor, and if the difference value between the second lifting speed and the first lifting speed is larger than a preset threshold value, winding and unwinding the winding, otherwise, normally.
Further, referring to fig. 5, the first lifting speed calculating method is as follows: calculating the lifting speed of each sampling interval in the time window, and filtering to remove the error value with overlarge deviation; and calculating an average value of the plurality of filtered lifting speeds to obtain a first lifting speed. Wherein, the current time t is acquired 1 ，t 2 ,...t n Lifting height H of corresponding load 1 ,H 2 ,...H n The rise and fall speeds over all sampling intervals are calculated and recorded as v 1 ，v 2 ，v 3 ...v n-1 The calculation formula is as follows:where i=1, 2,..n-1.
The total duration of t1 to tn is a time window, and the time difference between every two adjacent sampling moments in t1 to tn is a sampling interval. The selection of the time window should be combined with the frequency requirement of the loose roll judgment. The time window is reduced, the frequency of the unreeling judgment can be improved, and the operation load of a system control unit is increased. In this embodiment, the time window may be 500-1000ms.
The sampling interval is selected by combining the real-time requirement of data, the sampling frequency of the sensor and the working condition characteristics of the lifting mechanism. The sampling interval is reduced, so that the real-time performance of the data is improved, the sampling frequency of the sensor is increased, and meanwhile, the acquired data is more likely to become inaccurate due to the influence of instantaneous impact of lifting motion. In this embodiment, the sampling interval may be selected to be 50-100ms.
Referring to fig. 6, the second lifting speed calculating method is as follows: in the time window, calculating the lifting speed of each sampling interval according to the motor rotating speed, and filtering to remove the error value with overlarge deviation; and calculating an average value of the plurality of filtered lifting speeds to obtain a first lifting speed. Specifically, at t respectively 1 ,t 2 ,...t n At the moment, the motor rotation speed N is obtained 1 ，N 2 ，...N n . For motor rotation speed N 1 ，N 2 ，...N n And filtering to eliminate error value with overlarge deviation. And respectively calculating the corresponding lifting speed for the plurality of rotation speed values after filtering, and calculating an average value for the obtained lifting speed to obtain a second lifting speed.
In the hoisting system, if parameters such as the motor rotation speed, the speed reducer speed ratio, the hoisting radius and the like are known, the hoisting speed is calculated by the following formula:wherein N is the motor rotation speed, and the unit is r/min; r is the winding radius in mm;i is the speed ratio of the speed reducer; v units mm/s.
The preset threshold A is a critical value for judging whether the unreeling occurs or not, and is set in advance and stored in a control unit of the system. If the absolute value of the difference between the second lifting speed and the first lifting speed is larger than A, the lifting speed corresponding to the motor rotating speed is larger than the actual lifting speed of the fork in the same time, and the difference between the lifting speeds exceeds the critical value of the occurrence of unreeling. In this case, the winding is loosened, so that the winding loosening alarm can be given, and otherwise, the winding is ended.
The embodiment also provides a loosening judgment device of the fork AGV hoisting system, by adopting the judgment method, the adopted first detection unit is a height sensor, and the second detection unit is a motor rotation speed sensor. The mounting position of the height sensor can be set according to the requirement, and the height sensor comprises a bottom part, a top part, a side part and the like of the frame, and is not limited.
Referring to fig. 3 and 4, the height sensor may be a wire-type encoder. The stay wire type encoder body is fixed at the bottom of the forklift frame, and the tail end of an encoder rope is fixed with the lifting mechanism. When the lifting mechanism acts, the rope is pulled out or retracted, and the encoder shaft is driven to rotate, so that an electric signal is generated. The height sensor may also be a laser rangefinder as shown in fig. 3 at 2. The laser transmitter and the receiver are fixed at the bottom of the frame, and the reflecting plate is fixed on the lifting mechanism. The laser beam emitted by the laser emitter irradiates the reflecting plate and is reflected, and then is received by the laser receiver, and the height information can be obtained by calculating the flight time of the laser.
In this embodiment, the selection of the preset threshold a should be combined with the requirements of the measurement accuracy, the error and the unreeling judgment accuracy of the sensor. The smaller A is, the higher the unreeling judgment precision is, but the requirement on the measurement precision of the sensor is improved, and the misjudgment risk is increased. In this embodiment, A may be selected to be 50-100mm/s.
Example two
Referring to fig. 7, a method for determining whether a pallet fork type AGV hoist lifting system is unwound is provided, in which state information of a motor and state information of a load are acquired, and whether the pallet fork type AGV hoist lifting system is unwound is determined according to the state information of the motor and the state information of the load in combination with a preset threshold. The state information of the motor is steering of the motor, the state information of the load is height of the load, and if the motor rotates in the direction of driving the load to descend within a certain time interval, and the height difference of the load is smaller than a preset threshold value, the winding is loosened.
In this embodiment, the lifting heights H1 and H2 of the load are acquired at times t1, t2, respectively. the time interval between t1 and t2 can be selected according to the actual lifting speed, and in this embodiment, the time interval between t1 and t2 can be selected to be 1-3s. And judging whether the motor steering in the time period from t1 to t2 rotates in the ascending or descending direction according to the acquired motor encoder signals. If the motor rotates towards the descending direction and the difference value between H1 and H2 is smaller than the threshold value A, the occurrence of unreeling is judged, unreeling alarm is carried out, and otherwise, the process is finished.
The embodiment also provides a loosening judgment device of the fork AGV hoisting system, by adopting the judgment method, the adopted first detection unit is a height sensor, and the second detection unit is a motor encoder.
The preset threshold A is a critical value for judging whether the lifting height is changed, and is set in advance and stored in the system control unit. If H1-H2 is less than A, indicating that the lift mechanism of the forklift is not lowered in the period from t1 to t2, but the motor is still rotating in the lowering direction, the winding will unwind in this case.
In this embodiment, the selection of the preset threshold a should be combined with the requirements of the lifting speed, the time interval between t1 and t2, and the judgment accuracy. In this embodiment, A may be selected to be 0.5-1mm.
Example III
Referring to fig. 8, a method for judging whether a fork type AGV hoisting system is unreeled is provided, wherein state information of a motor and state information of a load are obtained, and whether the reels are unreeled or not is judged according to the state information of the motor and the state information of the load and by combining a preset threshold value. The state information of the motor is steering of the motor, and the state information of the load is actual load; if the motor rotates towards the descending direction in the current state and the actual load is smaller than the preset threshold value, the winding is unwound.
The actual load is related to the torque of the motor, which is related to the current of the motor, and when the motor current is less than the rated current, the motor current is reduced as the motor output torque is reduced, and the actual load is small. The current load situation can be determined by the current of the motor. And if the motor rotates towards the descending direction in the current state and the current I of the motor is smaller than the preset threshold A, winding and unwinding are performed, and winding and unwinding alarming is performed.
The embodiment also provides a device for judging the unreeling of the fork AGV hoisting system, the judging method is adopted, the adopted first detection unit is a current sensor, and the adopted second detection unit is a motor encoder. The control unit obtains motor current and motor steering from the first detection unit and the second detection unit respectively, and judges motor torque through the motor current, so as to judge whether to unwind or not.
The preset threshold A is a current critical value for judging whether the motor torque is too small or not, and is set in advance and stored in the control unit. The preset threshold a represents the minimum lifting load of the lifting mechanism (typically the lifting mechanism's own weight). When the lifting mechanism encounters an obstacle in the descending process and is unwound, the torque of the lifting mechanism and the load acting on the motor is counteracted by the obstacle, so that the output torque of the motor is smaller than the torque required by the minimum lifting load.
The foregoing is merely illustrative of specific embodiments of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modification of the present invention by using the design concept shall fall within the scope of the present invention.

Claims (8)

1. A method for judging the unreeling of a fork type AGV hoisting system is characterized in that: acquiring state information of a load and state information of a motor, wherein the state information of the load comprises the height of the load or the actual load, the state information of the motor comprises the rotating speed of the motor or the steering of the motor, and whether the coil is unwound or not is judged according to the state information of the motor and the state information of the load and by combining a preset threshold value;
when the state information of the motor is the rotating speed of the motor, the state information of the load is the height of the load; calculating a first lifting speed according to the height of the load within a certain time window, calculating a second lifting speed according to the rotating speed of the motor, and winding and unwinding if the difference between the second lifting speed and the first lifting speed is greater than a preset threshold value;
when the state information of the motor is the steering direction of the motor, the state information of the load is the actual load; if the motor rotates towards the descending direction in the current state and the actual load is smaller than the preset threshold value, the winding is unwound.
2. The method for determining the unreeling of the fork type AGV hoisting system of claim 1 wherein: the first lifting speed calculating method comprises the following steps: in the time window, calculating the lifting speed of each sampling interval according to the load height, and filtering to remove the error value with overlarge deviation; and calculating an average value of the plurality of filtered lifting speeds to obtain a first lifting speed.
3. The method for determining the unreeling of the fork type AGV hoisting system of claim 1 wherein: the second lifting speed calculating method comprises the following steps: and in the time window, filtering the motor rotating speed to remove an error value with overlarge deviation, calculating the lifting speed of each sampling interval according to the motor rotating speed, and calculating an average value of a plurality of lifting speeds to obtain a second lifting speed.
4. The method for determining the unreeling of the fork type AGV hoisting system of claim 1 wherein: the state information of the motor is steering of the motor, the state information of the load is the height of the load, and if the motor rotates in the direction of driving the load to descend within a certain time interval, and the height difference of the load is smaller than a preset threshold value, the winding is unwound.
5. The method for determining the unreeling of the fork type AGV hoisting system of claim 1 wherein: the actual load is related to the current of the motor, and if the motor rotates towards the descending direction in the current state and the current of the motor is smaller than a preset threshold value, the winding is unwound.
6. A fork formula AGV hoist hoisting system's loose roll judgement device, its characterized in that: a method for determining the unwinding of a fork type AGV hoist system according to any one of claims 1 to 5, comprising
The first detection unit acquires state information of the load;
the second detection unit is used for acquiring state information of the motor;
and the control unit is used for processing according to the state information of the load and the state information of the motor and judging whether the coil is unwound or not by combining a preset threshold value.
7. The roll unwind determination apparatus of a pallet fork type AGV hoist lift system of claim 6, wherein: the first detection unit is a height sensor or a current sensor.
8. The roll unwind determination apparatus of a pallet fork type AGV hoist lift system of claim 6, wherein: the second detection unit is a motor rotating speed sensor or a motor encoder.
CN202010436010.5A 2020-05-21 2020-05-21 Method and device for judging unreeling of fork type AGV hoisting system Active CN113697721B (en)

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Publication number Priority date Publication date Assignee Title
US5462136A (en) * 1994-03-03 1995-10-31 The Raymond Corporation Prevention of slack lift chains on a man-up lift truck
JP2001240231A (en) * 2000-03-02 2001-09-04 Amada Co Ltd Method and device for monitoring tension of rotary traveling member
JP2003238091A (en) * 2002-02-15 2003-08-27 Nippon Yusoki Co Ltd Fork lift truck
CN101935737A (en) * 2010-09-07 2011-01-05 中冶华天南京自动化工程有限公司 Device for integrally detecting height of oxygen lance height and looseness and tightness of steel wire rope of oxygen gun
CN102030279A (en) * 2010-12-31 2011-04-27 徐州重型机械有限公司 Crane and anti-over-discharging protection device of hoisting rope thereof
CN202848953U (en) * 2012-10-19 2013-04-03 武汉钢铁(集团)公司 Rope loosing detecting device of winch

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11565923B2 (en) * 2019-02-19 2023-01-31 Crown Equipment Corporation Chain slack detection system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5462136A (en) * 1994-03-03 1995-10-31 The Raymond Corporation Prevention of slack lift chains on a man-up lift truck
JP2001240231A (en) * 2000-03-02 2001-09-04 Amada Co Ltd Method and device for monitoring tension of rotary traveling member
JP2003238091A (en) * 2002-02-15 2003-08-27 Nippon Yusoki Co Ltd Fork lift truck
CN101935737A (en) * 2010-09-07 2011-01-05 中冶华天南京自动化工程有限公司 Device for integrally detecting height of oxygen lance height and looseness and tightness of steel wire rope of oxygen gun
CN102030279A (en) * 2010-12-31 2011-04-27 徐州重型机械有限公司 Crane and anti-over-discharging protection device of hoisting rope thereof
CN202848953U (en) * 2012-10-19 2013-04-03 武汉钢铁(集团)公司 Rope loosing detecting device of winch

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