JPH0138758B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a moving device for a boom-end work platform in an aerial work vehicle, and more specifically, a work platform such as a gondola is provided at the end of the boom, and the present invention relates to a moving device for a boom-end work platform in an aerial work vehicle. This invention relates to a boom-end workbench moving device that allows the platform to be moved at a constant speed along a work surface where painting or welding is performed while maintaining a constant interval.

[Conventional technology]

Conventionally, as shown in Fig. 1, when painting or welding the outer surface 2 of the hull of a ship 1 under construction, a turret 4 is erected on the ground 3 on the side of the ship, and a worker 5 climbs onto it and sequentially lowers it. or while moving upwards.
Working on a vertical work surface.

Since such work on a turret is dangerous, as a solution to this problem, an aerial work vehicle 8 having a gondola 7 attached to the tip of a boom 6 as shown in FIG. 2 is used. This work is performed by the outrigger 9
After placing the work vehicle 8 in place, a worker is placed on the gondola 7, and the swing motor 11,
This is done by appropriately operating hydraulic equipment 15 such as the undulating cylinder 12 and the telescopic cylinder 13 to move the gondola 7 at the end of the boom 6 while maintaining it at a constant distance L suitable for the work from the work surface 14.

However, if the workbench 14 is vertical, for example,
If only the undulating cylinder 12 is contracted or expanded, the gondola 7 will draw a circular arc trajectory and approach or move away from the work surface 14. Therefore, unless the extension amount of the telescoping cylinder 13 is appropriately changed, the gondola 7 will move against the work surface. Unable to maintain constant spacing.

This operation must be performed sequentially by the operator using the control unit during painting work, etc., which requires time and effort to move the gondola, and it is difficult to move the gondola at a constant speed along a vertical work surface. However, there are disadvantages in that the coating lacks uniformity and the work efficiency is significantly reduced.

[Problem to be solved by the invention]

By the way, Japanese Unexamined Patent Publication No. 52-39295 describes an automatic copying device that can displace a gondola installed at the tip of a boom in the horizontal direction while maintaining the same distance from the work surface. ing. This uses two sensors to detect the facing distance between the gondola and the work surface, and then controls the rotation of the gondola so that it aligns with the work surface.It also controls the rotation angle of the boom and rotates the gondola again. By adding rotation control, it is possible to correct the posture.

However, the speed of movement of the gondola relative to the work surface is not maintained constant, and even if such control were applied to a gondola moving vertically, the boom itself would not be mounted on a trolley, etc. Therefore, it is almost impossible to move the gondola upward or downward, which is the displacement direction of the gondola. Therefore, if you try to move only the gondola attached to the tip of the boom in the vertical direction without raising or lowering the boom itself, it is necessary to employ a number of control means and drive means, and it is difficult to know the specifics. It is desirable to clarify the configuration and establish a technology that can realize it.

The present invention was made in view of the above-mentioned needs, and its purpose is to maintain a constant distance between the gondola and the work surface by avoiding the operator having to manually adjust the distance between the gondola and the work surface. Another object of the present invention is to provide a moving device for a boom end work platform in an aerial work vehicle that can automatically move a gondola vertically at a commanded constant speed.

[Means to solve the problem]

The present invention is equipped with hydraulically actuated equipment such as a swing motor for displacing a workbench attached to the tip of a boom, a hoisting cylinder, and a telescoping cylinder. It is applied to aerial work vehicles that can move the platform up and down while maintaining it at a fixed distance from the work surface.

Its features include, as shown in FIGS. 3 and 4, a control means 20 that operates to automatically move the workbench 7 from a predetermined reference position 16 on the work surface 14; will be provided. The control means 20 includes a reference position command unit 21 that issues a command to place the workbench 7 at the reference position 16, and a reference position command unit 21 that gives an instruction to automatically move the workbench 7 from the reference position 16 in which direction. A movement command section 22 having a movement operation section 27 that commands the movement speed and a speed command section 28 that commands the speed of movement thereof.
and will be provided.

Then, the altitude sensor 32 detects the distance between the workbench 7 and the specific position 17, and the altitude H ₁ , H ₂ of the workbench 7 measured by the altitude sensor 32 before and after a predetermined minute time Δt. The difference between H ₁ − _{H 2}
A speed calculation processing unit 33 receives the speed signal of the workbench 7 calculated based on the speed signal and the target movement speed signal commanded by the speed command unit 28, and determines the amount of oil to be supplied and discharged to the undulation cylinder 12 or the telescopic cylinder 13.
There is a moving speed holding means 31 having the following. Also,
A distance sensor 39 detects the distance between the workbench 7 and the work surface 14, and the distance detected by the distance sensor 39 is compared with a predetermined target distance,
Telescopic cylinder 13 or undulation cylinder 12
There is a constant interval maintaining means 38 that includes a distance calculation processing section 40 that determines the amount of oil to be supplied and discharged to and from.

Further, the supply and discharge direction of each circuit of the undulation cylinder 12 and the telescopic cylinder 13 is switched in response to a command from the movement operation section 27, and in response to a control signal from the movement speed holding means 31, the supply and discharge amount of hydraulic oil is changed. A flow control valve 58 that adjusts the flow rate, and a flow control valve 59 that adjusts the supply/discharge direction and amount of hydraulic oil in response to a control signal from the constant interval maintaining means 38 are interposed. A hydraulic circuit 55 is provided.

[Effect]

In the movement operation section 27, for example, downward movement of the workbench 7 is selected. Then, for the time being, the undulation cylinder 12 is operated. At this time, the altitude sensor 32 detects the distance between the workbench 7 and the specific position 17. A speed signal of the workbench 7 calculated based on the height difference H ₁ −H ₂ of the workbench 7 measured before and after a predetermined minute time Δt, and a target movement speed signal commanded by the speed command unit 28 From,
The speed calculation processing section 33 determines the amount of oil to be supplied and discharged by the flow rate control valve 58, and the undulation cylinder 12 is operated to contract.

On the other hand, the distance sensor 39 detects the distance between the workbench 7 and the work surface 14. By comparing the detected distance and a predetermined target distance, the distance calculation processing section 40 determines the amount of oil to be supplied and discharged by the flow rate control valve 59, and the telescopic cylinder 13 is operated to contract.

In this way, the luffing cylinder 12 is actuated at a controlled speed and the telescoping cylinder 1
By automatically adjusting the operating speed of 3, the work platform 7 is moved downward in the vertical plane at a commanded constant speed while maintaining a constant distance L from the work surface 14.

〔Effect of the invention〕

According to the present invention, while measuring the moving speed of the workbench in the vertical direction, the undulation cylinder or the telescopic cylinder is actuated so that this speed corresponds to the speed commanded by the operator, and the movement between the workbench and the work surface is controlled. While the spacing is measured, the telescoping or undulating cylinder can be extended and retracted at an automatically adjusted rate to maintain a predetermined constant spacing.

Therefore, the operator can maintain the work platform and work surface at a constant distance without having to sequentially correct the position of the gondola from the control unit, and can command the gondola upward or downward along the vertical work surface. It can be moved automatically at high speed, the coating etc. will be uniform, and the work efficiency will also be significantly improved.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples thereof.

FIG. 3 shows the operation of the undulating cylinder 12 based on the control signal of the moving speed holding means 31, and the operation of the telescopic cylinder 13 based on the control signal of the constant interval holding means 38, by automatically changing the speed and expanding and contracting. , the gondola 7 at the tip of the boom 6 and the work surface 1
4 is a configuration diagram of a moving device for a boom end work platform in an aerial work vehicle that can move at a constant speed in the vertical direction while maintaining a constant distance from the boom end work platform.

This includes a control means 20, a moving speed holding means 31, a constant distance holding means 38, and a luffing cylinder 12 which is a hydraulically operated device 15.
The hydraulic circuit 55 that operates the telescopic cylinder 13 is its main configuration.

The control means 20 is provided on the gondola 7 or on the car side, or on both sides as necessary, and is used by the operator to issue commands for moving the gondola 7 and commands for its movement speed, and is used to control the starting point of painting on the workbench 14. A reference position command unit 21 sets the gondola 7 at a reference position 16 (see Fig. 4), and instructs which direction to move the gondola 7 up or down from this reference position 16, and automatically sets the gondola 7 at any speed. The gondola 7 is also provided with a movement command unit 22 through which an operator instructs whether to move the gondola 7.

The reference position command section 21 includes a direction switching valve 57 and a flow rate control valve 5 which are interposed in a hydraulic circuit 55, which will be described later.
It has a swing command section 23, a levitation command section 24, and a telescopic command section 25 which switch the supply/discharge passages 8 and 59 and actuate predetermined hydraulically operated equipment 15, and also have an emergency control section 23 that switches the supply/discharge passages 8 and 59 and operates a predetermined hydraulically operated device 15. A stop command unit 26 is also provided.

The movement command unit 22 includes a movement operation unit 27 that commands which direction to automatically move the gondola 7 from the reference position 16 up or down, and a speed command unit 28 that commands the speed of movement thereof. There is. Note that the movement command section 22 may be configured such that the movement operation section 27 and the speed command section 28 are integrated so that a movement command and a movement speed command can be issued with one operation.

The moving speed holding means 31 includes an altitude sensor 32 that detects the altitude of the gondola 7 from a specific position, for example, the ground 17 (see FIG. 4), and an altitude sensor 32 that measures the altitude before and after a predetermined minute time Δt. The difference between the heights H ₁ and H ₂ of gondola 7 is H ₁ −
A flow rate control described below adjusts the amount of oil supplied to and discharged from the undulation cylinder 12 or the telescopic cylinder 13 in response to the speed signal of the workbench 7 calculated based on H ₂ and the target movement speed signal commanded by the speed command unit 28. The valve 58 includes a speed calculation processing section 33 that electrically inputs the opening adjustment amount of the valve 58 .

The altitude sensor 32 is an ultrasonic sensor mounted downward on the side of the gondola 7, as shown in FIG. It is a non-contact type that measures the time until

As shown in FIG _. 5, the speed calculation processing unit 33 measures the altitudes H ₁ and _{H 2} before and after the minute time Δt using the altitude sensor 32, and determines whether the gondola 7 is actually A speed calculation section 34 that calculates the speed at which the vehicle is moving, (H ₁ - H ₂ )/Δt, and this speed calculation section 3
4 and the movement speed commanded by the speed command section 28 of the movement command section 22, and convert this into an electrical signal to generate a control signal for driving the solenoid of the pilot section 58a of the flow control valve 58. It has a speed control section 35 that outputs. A pilot lamp 29 is attached to the control means 20 to indicate that the speed calculation processing section 33 is in operation.

The constant distance holding means 38 is attached to the lower surface of the gondola 7 and maintains a distance L between the gondola 7 and the work surface 14.
A distance sensor 39 that detects the distance, and a flow control valve 59 (described later) that compares the distance detected by the distance sensor 39 with a predetermined target distance and adjusts the amount of oil supplied to and discharged from the telescopic cylinder 13. It has a distance calculation processing section 40 that electrically inputs the opening adjustment amount.

For example, as shown in FIG. 4, this distance sensor 39 includes a rod body 42 restorably supported by a spring 41 on the lower surface of the gondola 7, and an electric resistance of a potentiometer 43 according to the displacement of this rod body 42. A roller 45 supported on the end of the rod body 42 is brought into contact with and rolled on the work surface 14, and the distance L is detected based on the amount of horizontal movement of the rod body 42. That is,
The amount of protrusion of the rod body 42 at the start of work is set to the target distance length, and if the length of the rod body 42 increases or decreases due to subsequent movement of the gondola 7, the length of the rod body 42 is adjusted according to the amount of change in order to correct the amount of change. and is configured to generate an electrical signal. Note that the distance sensor 39 may be one that uses the above-mentioned ultrasonic sensor and measures the time it takes to receive the ultrasonic wave reflected on the work surface 14.

As shown in FIG. 6, the distance calculation processing section 40 includes, for example, a central processing unit 49 including an A/D converter 46, a read-only memory 47, and a random access memory 48, and a D/A converter 50. have,
In response to the amount of voltage change in the potentiometer 43, a control signal for driving a solenoid of a pilot portion 59a of a flow rate control valve 59, which will be described later, is output. Note that this distance calculation processing section 4
From 0 onwards, a pilot lamp 30 is associated with said control means 20 to indicate that it is activated.

In the hydraulic circuit 55, a directional switching valve 57 and flow control valves 58 and 59 are interposed in each circuit of the hydraulic pump 56 and the hydraulically operated equipment 15.

The direction switching valve 57 is a solenoid valve that supplies and discharges hydraulic oil to and from the swing motor 11 and switches its direction, and operates based on a command from the swing command unit 23 in the reference position command unit 21.

The flow rate control valve 58 switches the direction of supply and discharge of hydraulic oil to the luffing cylinder 12 to which the pilot check valve 12a is attached, and also adjusts the amount of oil sent. It operates based on signals from the section 22 and the moving speed holding means 31. Note that a regulation valve 66, which will be described later, is interposed in the circuit between the flow rate control valve 58 and the undulating cylinder 12.

The other flow control valve 59 switches the direction of supply and discharge of hydraulic oil to and from the telescopic cylinder 13 to which the double pilot check valve 13a is attached, and further adjusts the amount of oil sent. It is operated by a control signal from the constant spacing means 38. Note that a regulation valve 67, which will be described later, is interposed in the circuit between the flow rate control valve 59 and the telescopic cylinder 13.

To briefly describe the flow rate control valves 58, 59, the main body 5 is connected to the pilot portions 58a, 59a.
8b, 59b is detected as a pilot pressure, the former is a solenoid driven by a control signal from the movement operation section 27 and the movement speed holding means 31, and the latter is driven by a control signal from the constant interval holding means 38. The opening degree of the valve body 59b is adjusted to a desired value.

The hydraulic circuit 55 described above is also provided with a relief valve 61 for the emergency cutoff valve 60 and means 62 for preventing the boom 6 from overturning. This overturn prevention means 62 restricts the gondola 7 from moving further in the deviation direction at the limit position determined by the weight of the gondola 7, the amount of extension and contraction of the boom 6, and its undulation angle.
This prevents the aerial work vehicle from falling over.

Briefly, the amount of expansion and contraction of the undulation cylinder 12 is detected by the amount of payout of the winding wire, etc., and the amount of expansion and contraction of the expansion and contraction cylinder 13 is detected by the amount of expansion sensor 63 having a potentiometer similar to that used in the distance sensor 39. In response to a signal from an elongation amount sensor 64 that detects the amount of elongation, an arithmetic processing section 65 outputs an opening/closing signal to regulation valves 66 and 67.

According to the configuration described above, the operation can be performed as follows.

First, the aerial work vehicle is placed at a predetermined location as shown in FIG. 2, and secured with outriggers 9. An operator inside the gondola 7 or on the car side, while keeping the movement command section 22 of the control means 20 shown in FIG.
The undulation command section 24 and the expansion/contraction command section 25 are operated. Then, actuate the hydraulically operated equipment 15,
Move the gondola 7 at the tip of the boom 6 to the reference position 1, which is the work start position on the work surface 14 shown in FIG.
Place it at 6. At this time, when each lever of the reference position command unit 21 is released, the direction switching valve 57 and the flow rate control valves 58, 59 are in the neutral position, and the hydraulic circuit 5
5 is locked, and the movements of the swing motor 11, the undulation cylinder 12 and the telescopic cylinder 13 are stopped.

Next, in order to start painting the work surface 14 below, for example, the reference position 16, the lever of the movement operation section 27 is operated to make the desired upward or downward movement, and the speed command section 28 is operated. A desired target movement speed is selected and commanded using, for example, a lever on a dial.

In response to one of these commands from the movement operation section 27, the flow rate control valve 58 is switched from the neutral position to the A position, and the undulation cylinder 12 starts its contraction operation. In response to this operation, the gondola 7 descends while approaching the work surface 14, but at this time,
The altitude sensor 32 measures altitudes H ₁ and H ₂ before and after a predetermined minute time Δt. Then, these are input to the speed calculation section 34 (see FIG. 5), where (H ₁ -H ₂ )/Δt=V _c is calculated.

Next, the difference between this V _c and the target movement speed V _d commanded by the speed command section 28 is determined by the speed control section 35.
[See FIG. 5], and a signal based on this ΔV=V _d −V _c is output to the flow rate control valve 58,
Drive the solenoid of the pilot portion 58a,
The oil supply amount is adjusted by controlling the valve opening degree of the main body portion 58b, and the contraction speed of the undulation cylinder 12 is adjusted so that the gondola 7 descends at the commanded target movement speed _Vd .

However, since the gondola 7 approaches the work surface 14 only by the reduction operation of the undulating cylinder 12, the distance sensor 39 of the constant distance maintaining means 38 detects the distance by the amount of horizontal movement of the rod body 42. In order to set the interval to the target distance L, the amount of voltage change in the potentiometer 43 is input as a control signal to the flow rate control valve 59 via the distance calculation processing section 40.

This control signal switches the flow rate control valve 59 to the D position to contract the telescopic cylinder 13, and also drives the solenoid of the pilot section 59a to control the opening degree of the valve of the main body section 59b, so that the amount of oil sent is controlled. The contraction speed of the telescopic cylinder 13 is changed.

The telescopic cylinder 13 has shrunk too much and the gondola 7
When the distance sensor 39 moves away from the fixed distance L, the distance sensor 39
detects this, and a control signal is inputted from the distance calculation processing section 40 to the flow rate control valve 59 again. This control signal switches the flow rate control valve 59 to the C position and adjusts the amount of oil fed.

Even if the descending speed of the gondola 7 changes due to the telescopic operation of the telescopic cylinder 13, the moving speed holding means 31 adjusts the contraction speed of the undulating cylinder 12 again, so that the descending speed of the gondola 7 changes. Never.

In this way, when the telescopic cylinder 13 is automatically extended and contracted by changing the speed so as to maintain the predetermined distance L based on the speed change reduction operation of the undulating cylinder 12, the gondola 7 approaches and moves away from the work surface 14. is avoided, and the gondola 7 can be lowered automatically at a commanded speed while always keeping a constant distance L from the work surface 14. Incidentally, when the gondola 7 and the work surface 14 are raised and lowered at different intervals _L1 , there is no difference from the above operation except that the initial position of the potentiometer 43 is different.

On the other hand, when moving gondola 7 upwards,
In the same manner as above, the flow control valve 58 is switched to the B position, the amount and speed of extension of the undulating cylinder 12 is controlled, and the telescopic cylinder 13 is extended or contracted in accordance with the operation, and the gondola 7 is always moved at a constant distance L.
Therefore, it can be automatically raised at a commanded speed. Therefore, the operator inside the gondola 7 can continue working at a uniform coating speed without operating the levers of the turning command section 23, the up/down command section 24, and the extension/contraction command section 25 of the control means 20.

The gondola 7 can be stopped by setting the lever of the movement command part 22 to neutral, and if necessary, by operating the lever of the emergency command part 26, the entire hydraulic circuit is locked by the emergency shutoff valve 60. You can also do that. In addition, since the regulation valves 66 and 67 are operated appropriately by the overturn prevention means 62, the aerial work vehicle will not overturn.

FIG. 7 shows an embodiment of a different boom end workbench moving device, in which the operation of the telescopic cylinder 13 is based on the control signal of the movement speed holding means 31, and the operation of the undulating cylinder 12 is based on the control signal of the constant interval holding means 38. By automatically changing speed and extending and contracting based on the above, the distance between the gondola 7 at the tip of the boom 6 and the work surface 14 can be maintained at a constant distance L, and the boom 6 can be moved at a constant speed in the vertical direction. .

This is the moving operation unit 2 that inputs control signals to the flow rate control valves 58 and 59 in the example shown in FIG.
7, the moving speed holding means 31 and the constant distance holding means 38 are connected to the flow rate control valves 59 and 58 of the circuits of the telescopic cylinder 13 and the undulating cylinder 12, respectively.
It was replaced with a new one.

According to this example, by operating the movement command section 22 of the control means 20, the movement speed holding means 3
1 expands and contracts the telescopic cylinder 13, while the distance sensor 39 of the constant distance holding means 38
A control signal is input to the flow rate control valve 58 via the distance calculation processing section 40 by detecting the distance L between the distance L and the distance L. Therefore, the amount of oil fed to the undulating cylinder 12 and the telescopic cylinder 13 is adjusted, and as in the above example, they are expanded and contracted appropriately, and the gondola 7 is prevented from approaching or leaving the work surface 14. As a result, also in this example, the gondola 7 is placed at a constant distance L from the work surface 14.
It can be raised or lowered at a constant speed.

In the two examples above, if an unmanned workbench equipped with work equipment is installed instead of the gondola at the tip of the boom and operated from the control means on the vehicle, work can be done remotely and automatically. can.

As explained in detail above, the reference position command part sets the workbench to the reference position, and the movement command part gives commands to automatically move the workbench from the reference position and its movement speed. an altitude sensor that detects the altitude from a specific position of the workbench, an elevation speed signal that is calculated based on the altitude signal detected by the altitude sensor, and a command from the movement command section. A moving speed holding means having a speed calculation processing unit that receives a target moving speed signal and controls the opening degree of the flow control valve, a distance sensor that detects the distance between the work table and the work surface, and this distance sensor. a distance calculation processing unit that compares the distance measured by the distance with the target distance and controls the opening degree of other flow rate control valves; and each hydraulically operated device is operated by these three means. Since it is equipped with a hydraulic circuit, it measures the vertical movement speed of the workbench and operates the undulation cylinder or telescopic cylinder to make this speed the target speed commanded by the operator, and also controls the workbench and work surface. The telescoping or undulating cylinder can be extended or retracted at an automatically adjusted speed to maintain a predetermined constant distance.

In addition, since the altitude sensor is a non-contact type, it is possible to set a specific position on the ground as the altitude reference,
It can be any other protrusion and no restrictions are imposed on its altitude measurement.

Therefore, the operator can maintain the work platform and work surface at a constant distance without having to sequentially correct the position of the gondola from the control unit, and can command the gondola upward or downward along the vertical work platform. It can be moved automatically at a target speed, the coating etc. can be uniform, and the work efficiency can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of conventional ship hull painting work, Fig. 2 is an installation diagram of an aerial work vehicle, Fig. 3 is a configuration diagram of a moving device for a boom end work platform of the present invention, and Fig. 4 is a device installed on a gondola. Fig. 5 is a configuration diagram of the speed calculation processing unit, Fig. 6 is a configuration diagram of the distance calculation processing unit, and Fig. 7 is a configuration of a different boom end work platform moving device. It is a diagram. 6...Boom, 7...Workbench (gondola), 1
2... Lifting cylinder, 13... Telescopic cylinder, 14... Working surface, 15... Hydraulic operating equipment, 1
6...Reference position, 17...Specific position (ground), 2
0...control means, 21...reference position command section, 22...movement command section, 27...movement operation section,
28...Speed command section, 31...Movement speed holding means, 32...Altitude sensor, 33...Speed calculation processing section, 38...Constant interval holding means, 39...Distance sensor, 40...Distance calculation processing section , 55... Hydraulic circuit, 58, 59... Flow rate control valve, L... Fixed interval.

Claims (1)

[Scope of Claims] 1. Hydraulic operating equipment such as a swing motor for displacing a workbench attached to the tip of a boom, a hoisting cylinder, and a telescoping cylinder are provided, and the amount of extension of the hoisting cylinder and the telescoping cylinder is mutually adjusted. However, in an aerial work vehicle that can move the work platform up and down while maintaining it at a constant distance from the work surface, from a predetermined reference position on the work surface,
A control means is provided that performs a control operation to automatically move the workbench, and the control means includes a reference position command unit that issues a command to place the workbench at a reference position;
a movement control unit that includes a movement operation unit that instructs in which direction the workbench is automatically moved from the reference position and a speed command unit that instructs the speed of movement thereof, and is specified as the workbench; An altitude sensor that detects the distance to the position, a speed signal of the work platform calculated based on the difference in altitude of the work platform measured by the altitude sensor before and after a predetermined minute time, and the speed command section. a moving speed holding means comprising a speed calculation processing unit that receives a commanded target moving speed signal and determines the amount of oil to be supplied and discharged to the undulating cylinder or the telescopic cylinder; and detecting the distance between the work table and the work surface. a distance sensor, and a distance calculation processing unit that compares the distance detected by the distance sensor with a predetermined target distance and determines the amount of oil to be supplied to and discharged from the telescopic cylinder or the undulation cylinder. The holding means, and each circuit of the undulating cylinder and the telescopic cylinder, the supply/discharge direction is switched in response to a command from the moving operation section, and the supply/discharge amount of hydraulic oil is changed in response to a control signal from the moving speed maintaining means. and a flow control valve that adjusts the supply/discharge direction and supply/discharge amount of hydraulic oil in response to a control signal from the constant interval maintaining means, each interposed in a hydraulic circuit. and, by operating the undulation cylinder or telescopic cylinder at a controlled speed and automatically adjusting the operating speed of the telescopic cylinder or the undulation cylinder, the work platform is maintained at a constant distance from the work surface. A moving device for a boom end work platform in an aerial work vehicle, characterized in that the boom end work platform of an aerial work vehicle can be moved upward or downward in a vertical plane at a commanded constant speed while being held.