JP4282828B2 - Leveling device for aerial work platforms - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a leveling device for an aerial work vehicle.
[0002]
[Prior art]
In an aerial work platform, a work table is mounted at the tip of a boom mounted on the vehicle in a swingable manner along the boom hoisting surface so that the work table is always lifted regardless of the boom hoisting operation. Is configured to maintain a constant posture (that is, a posture in which the floor surface is horizontal).
[0003]
And it is a leveling device that holds the posture of the work table, and various structures have been proposed conventionally. One of them is shown in FIG. 7. A boom 43 is mounted on a swivel base 42 mounted on a vehicle 41 so that the boom 43 can be raised and lowered, and the boom 43 is raised and lowered by a hoisting cylinder disposed between the boom 43. While being driven, a work table 44 is pivotably connected to the tip of the boom 43 along the boom undulation surface. A first leveling cylinder 46 is provided between the base end portion of the boom 43 and the swivel base 42 in parallel with the hoisting cylinder 45, and between the tip of the boom 43 and the work table 44. The second leveling cylinder 47 is arranged respectively, and both the leveling cylinders 46 and 47 are hydraulically linked. When the first leveling cylinder 46 is expanded and contracted following the expansion and contraction of the hoisting cylinder 45, that is, the hoisting movement of the boom 43, the second leveling cylinder 47 expands and contracts in conjunction with the expansion and contraction. The platform 44 is always maintained in a horizontal posture regardless of the undulation of the boom 43.
[0004]
In the leveling device having such a structure, since the leveling cylinders 46 and 47 follow the movement of the hoisting cylinder 45, the horizontal posture of the work table 5 is maintained regardless of the hoisting angular velocity of the boom 3. There is no problem in the operation of the aerial work vehicle. However, two leveling cylinders are required and there is a problem that the structure is complicated or the cost is increased due to the configuration in which these are connected to be interlocked.
[0005]
As one method for solving such a problem, a leveling cylinder 47 is disposed only between the tip of the boom 43 and the work table 44 as in an aerial work vehicle shown in FIG. Without being related to the operation of the hoisting cylinder 45, the hoisting operation of the boom 43 is performed according to a signal related to the hoisting of the boom 43, for example, the hoisting angle of the boom 43 or the detected value of the potentiometer provided on the work table 44. There has been proposed one in which the posture of the work table 44 is always kept horizontal.
[0006]
[Problems to be solved by the invention]
However, as in the aerial work vehicle shown in FIG. 8, in the configuration in which the horizontal posture of the work table 44 is maintained by the independent operation leveling cylinder 47 that does not follow the movement of the hoisting cylinder 45, depending on the operation state, There is a concern that the horizontal maintenance action of the work table 44 may be impaired, and the work on the work table 44 may be hindered.
[0007]
That is, in order to maintain the horizontal posture of the work table 44, it is necessary to change the posture of the work table 44 following the raising and lowering operation of the boom 43. However, the maximum extending / contracting speed of the leveling cylinder 47 and the maximum angular speed thereof are fixedly set according to the design specifications of the leveling cylinder 47. Therefore, if the expansion / contraction speed of the hoisting cylinder based on the lever operation by the operator, and eventually the angular speed thereof exceeds the maximum angular speed of the leveling cylinder 44, the hoisting operation of the boom 43 is performed in the hoisting operation of the boom 43. The posture change cannot be followed, and as a result, the horizontal posture of the work table 44 cannot be maintained.
[0008]
The problem of the collapse of the horizontal posture of the work table 44 is a structure in which the number of hoisting cylinders involved in hoisting the boom is large (for example, as shown in FIG. 1, the base end driven by hoisting cylinders 17 as hoisting cylinders). The so-called “multi-joint boom” having the boom 3 and the tip boom 4 driven by the hoisting cylinder 22 at the tip of the base end boom 3 becomes more conspicuous.
[0009]
Accordingly, the present invention has been made with the object of providing a leveling device for an aerial work platform with high reliability that can maintain the posture of the work table at all times regardless of the boom angular velocity. It is a thing.
[0010]
[Means for Solving the Problems]
In the present invention, the following configuration is adopted as a specific means for solving such a problem.
[0011]
In the first invention of the present application, a proximal boom 3 is provided on the vehicle 1 and a next-stage boom is provided at the distal end of the proximal-end boom) so that it can be raised and lowered in sequence, and the most advanced boom 4 in the next-stage boom. The working table 5 is attached to the tip of the boom so as to be swingable along the boom hoisting surface, and hoisting cylinders 17 and 22 are disposed between the vehicle 1 and the base boom 3 and between the boom stages, respectively. A horizontal maintenance drive means 27 is arranged between the cutting edge boom 4 and the work table 5 so that the work table 5 can be kept horizontal regardless of the up and down movement of each boom stage. In the leveling device for an aerial work vehicle constructed as described above, the sum of the required angular velocities “ω1”, “ω2”,... Of the hoisting cylinders 17, 22 is the allowable maximum angular velocity of the horizontal maintenance drive means 27. Beyond “ωa” In this case, the required angular velocities “ω1”, “ω1”, “ωc” so that the total value “ωc” of the actual angular velocities “ωc1”, “ωc2”,. It is characterized by having speed regulating means 24 for regulating ω2 ”,.
[0012]
In the second invention of the present application, a base end boom 3 is provided on the vehicle 1 and a next-stage boom is provided at the front end of the base-end boom 3 so as to be raised and lowered in order, and the most advanced boom 4 in the next-stage boom is provided. The working table 5 is attached to the tip of the boom so as to be swingable along the boom hoisting surface, and hoisting cylinders 17 and 22 are disposed between the vehicle 1 and the base boom 3 and between the boom stages, respectively. A horizontal maintenance drive means 27 is arranged between the cutting edge boom 4 and the work table 5 so that the work table 5 can be kept horizontal regardless of the up and down movement of each boom stage. In the leveling device for an aerial work vehicle constructed as described above, the sum of the required angular velocities “ω1”, “ω2”,... Of the hoisting cylinders 17, 22 is the allowable maximum angular velocity of the horizontal maintenance drive means 27. Beyond “ωa” In this case, based on the ratio “ωa / ωb” of the allowable maximum angular velocity “ωa” and the total value “ωb”, the total of the actual angular velocities “ωc1”, “ωc2”,. It is characterized by comprising speed regulating means 24 for regulating the required angular velocities “ω1”, “ω2”,... So that the value “ωc” is equal to or less than the allowable maximum angular velocity “ωa”.
[0013]
【The invention's effect】
In the present invention, the following effects can be obtained by adopting such a configuration.
[0014]
(1) According to the leveling device for an aerial work vehicle according to the first invention of the present application, the total value “ωb” of the required angular velocities “ω1”, “ω2”,. When the allowable maximum angular velocity “ωa” of the horizontal maintaining drive means 27 is exceeded, that is, when the undulating cylinders 17 and 22 are operated at the required angular velocities “ω1”, “ω2”,. When the operation of the drive means 27 cannot follow and there is a risk that the horizontal maintenance of the work table 5 may be impaired, the speed regulating means 24 causes the actual angular velocities “ωc1”, “ωc2”, The required angular velocities “ω1”, “ω2”,... Are regulated so that the total value “ωc” of the ωc becomes equal to or less than the allowable maximum angular velocity “ωa”. As a result, the followability of the change in the angular velocity of the horizontal maintaining drive means 27 with respect to the change in the angular velocity of the hoisting cylinders 17 and 22 is reliably ensured, and the above work is performed regardless of the hoisting operation of the booms 3 and 4. The posture of the table 5 is always kept horizontal, and the reliability when working at a high place using the work table 5 is further enhanced.
[0015]
(2) According to the leveling device for an aerial work vehicle according to the second invention of the present application, the total value “ωb” of the required angular velocities “ω1”, “ω2”,. When the allowable maximum angular velocity “ωa” of the horizontal maintaining drive means 27 is exceeded, that is, when the undulating cylinders 17 and 22 are operated at the required angular velocities “ω1”, “ω2”,. When the operation of the driving means 27 cannot follow and there is a risk that the horizontal maintenance of the work table 5 may be impaired, the speed regulating means 24 causes the ratio “ωa” between the allowable maximum angular velocity “ωa” and the total value “ωb”. / Ωb ”, the required angular velocities“ ωc ”of the undulating cylinders 17 and 22 are set so that the total value“ ωc ”of the actual angular velocities“ ωc1 ”,“ ωc2 ”,. "ω1", "ω2", ... Be regulated. As a result, the followability of the change in the angular velocity of the horizontal maintaining drive means 27 with respect to the change in the angular velocity of the hoisting cylinders 17 and 22 is reliably ensured, and the above work is performed regardless of the hoisting operation of the booms 3 and 4. The posture of the table 5 is always kept horizontal, and the reliability when working at a high place using the work table 5 is further enhanced.
[0016]
In particular, as in the present invention, the required angular velocities “ω1”, “ω2”,... Are regulated based on the ratio “ωa / ωb” between the allowable maximum angular velocity “ωa” and the total value “ωb”. The actual angular velocities “ωc1”, “ωc2”,. ”,... Are proportionally distributed according to their sizes, so that the undulation angular velocity of the booms 3 and 4 is reduced as a whole. It has a relative undulation angular velocity as intended, and the operator does not feel uncomfortable with respect to the undulation operation of the booms 3 and 4, so that good operability is maintained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a leveling device for an aerial work vehicle according to the present invention will be described in detail.
FIG. 1 shows an aerial work vehicle equipped with a leveling device according to the present invention. This aerial work vehicle has a first hoisting cylinder in which a telescopic base end boom 3 is movably mounted on a swivel base 2 that is pivotably mounted on a vehicle 1 and is disposed between the swivel base 2. 17, the telescopic boom boom 4 is attached to the distal end portion of the proximal boom 3 so as to be movable up and down along a plane parallel to the undulating surface of the proximal boom 3. The hoisting drive is enabled by the second hoisting cylinder 22 disposed between the distal end of the proximal boom 3. A work table 5 is attached to the tip of the tip boom 4 so as to be swingable along a surface parallel to the undulation surface of the tip boom 4. The work table 5 is attached to the tip of the tip boom 4. It can be driven to swing by a leveling cylinder 27 (corresponding to “horizontal maintaining drive means 27” in the claims) disposed between them.
[0018]
Then, in this aerial work platform, the leveling cylinder 27 is operated in response to the hoisting operation of the booms 3, 4 accompanying the operation of the hoisting cylinders 17, 22, and the work table 5 is placed on its floor. The posture is controlled so that the surface is always level.
[0019]
By the way, in order for the posture of the workbench 5 to be always kept horizontal, the raising / lowering angular velocities of the booms 3, 4, that is, the total value of the angular velocities of the hoisting cylinders 17, 22, The swing angular velocity, that is, the angular velocity of the leveling cylinder 27 needs to be smaller. In this case, the allowable maximum angular velocity of the work table 5 is defined by the allowable maximum angular velocity of the leveling cylinder 27, and the allowable maximum angular velocity of the leveling cylinder 27 is fixed to a constant value based on the design specifications of the leveling cylinder 27. Is. Therefore, when the total value of the angular velocities of the undulation cylinders 17 and 22 exceeds the allowable maximum angular velocity of the leveling cylinder 27, the angular velocities of the undulation cylinders 17 and 22 are regulated in the decreasing direction and after the regulation. It is necessary to make the total value of the angular velocities below the allowable maximum angular velocity of the leveling cylinder 27.
[0020]
From this point of view, the invention of the present application regulates the angular velocity of the hoisting cylinders 17 and 22 when the total value of the hoisting angular velocities of the hoisting cylinders 17 and 22 exceeds the allowable maximum angular velocity of the leveling cylinder 27. It suggests a way. Hereinafter, this will be specifically described based on the embodiment.
[0021]
First embodiment
FIG. 2 is a control block diagram of the leveling device for an aerial work vehicle according to the first embodiment.
[0022]
In this aerial work platform, the raising / lowering operation of each boom is performed based on the operation of the proximal boom raising / lowering operation lever 11 and the distal boom raising / lowering operation lever 12. Further, the swinging motion of the work table 5 corresponding to the hoisting operation of the booms 3 and 4 is performed based on the hoisting angle of the booms 3 and 4. The raising / lowering operation of the booms 3 and 4 and the swinging operation of the work table 5 are different in control form between “normal operation” and “abnormal operation”. Here, “in normal operation” refers to the case where the sum of the angular velocities of the undulation cylinders 17 and 22 does not exceed the allowable maximum angular velocity of the leveling cylinder 27, and “in abnormal operation”. This is the case where the total value of the angular velocities of the undulation cylinders 17 and 22 exceeds the allowable maximum angular velocity of the leveling cylinder 27.
[0023]
First, the control mode during “normal operation” will be described.
[0024]
When the proximal end boom raising / lowering operation lever 11 and the distal end boom raising / lowering operation lever 12 are operated by an operator, an operation signal corresponding to the operation amount is sent to the first command value calculation means 14 and the second command value calculation means 19. Each is entered. The first command value calculating means 14 and the second command value calculating means 19 receive the operation signal, and cause the booms 3 and 4 to respond to the operation signals via the hoisting cylinders 17 and 22, respectively. The command values of the first undulation control valve 16 and the second undulation control valve 21 that are required for the undulation operation are calculated.
[0025]
In this embodiment, the command values are given as the required angular velocities “ω1” and “ω2” of the hoisting cylinders 17 and 22, respectively. The required angular velocities “ω1” and “ω2” are input to the first undulation control valve 16 and the second undulation control valve 21 as actual angular velocities “ωc1” and “ωc2” via the subtracters 15 and 20, respectively. The When the subtracters 15 and 20 do not perform the subtraction process (that is, “normal operation”), the required angular velocities “ω1” and “ω2” are the actual angular velocities “ωc1” and “ωc2”. Is input to the first undulation control valve 16 and the second undulation control valve 21.
[0026]
The first undulation control valve 16 and the second undulation control valve 21 are operated based on the actual angular velocities “ωc1” and “ωc2” from the first command value calculation means 14 and the second command value calculation means 19. As a result, the hoisting cylinders 17 and 22 are expanded and contracted at angular velocities corresponding to the actual angular velocities “ωc1” and “ωc2”, respectively, and the booms 3 and 4 are appropriately driven to undulate.
[0027]
The undulation angles of the booms 3 and 4 are respectively detected by the first undulation angular velocity detection means 18 and the second undulation angular velocity detection means 23, and the detected values are the speed regulation means 24 and the third command value calculation means described below. 25. As will be described later, at the time of “abnormal operation”, the values after the subtraction process is performed on the required angular velocities “ω1” and “ω2” are the actual angular velocities “ωc1” and “ωc2”. The values are input to the control valve 16 and the second undulation control valve 21, respectively.
[0028]
On the other hand, the leveling cylinder 27 is driven to expand and contract by actuating the leveling control valve 26 based on the command value output from the third command value calculation means 25, and swings the work table 5 to change its posture. Keep level. In this case, in the third command value calculation means 25, the work table 5 is moved based on the hoisting angles of the booms inputted from the first hoisting angular speed detecting means 18 and the second hoisting angular speed detecting means 23. The command value of the leveling control valve 26 necessary for maintaining the level is calculated.
[0029]
The third command value calculation means 25 is inputted with the current position of the work table 5 (that is, the posture in the swing direction) from the work table position detection means 28. An input signal from the position detection means 28 is used as feedback control information on the position of the work table 5, and a reliable follow-up of the posture of the work table 5 with respect to changes in the undulation angle of each boom 3, 4 is ensured. The
[0030]
In this way, during the “normal operation”, the raising and lowering operations of the booms 3 and 4 are not affected by the operation of the work table 5, and the proximal boom raising and lowering operation lever 11 and the leading boom raising and lowering operations are not performed. This operation is executed based on the operation of the operation lever 12. In this case, it is determined from the detected values of the hoisting angle detecting means 18 and 23 that the booms 3 and 4 do not follow the hoisting operation amounts of the hoisting operation levers 11 and 12. Sometimes, the hoisting operation of the booms 3 and 4 can be stopped at that time. Similarly, when it is determined from the detection value of the work table position detection means 28 that the posture of the work table 5 does not follow the change in the undulation angle of the booms 3 and 4, the booms 3. , 4 can be configured to stop at the time.
[0031]
Next, an operation mode “at the time of abnormal operation” will be described.
[0032]
In the “abnormal operation”, an operation form in which restriction control by the speed restriction means 24 described below is added to the operation form in “normal operation” is adopted. That is, the speed restricting means 24 includes the requested angular velocities “ω1” and “ω2” from the first command value calculating means 14 and the second command value calculating means 19, and the first undulating angular speed detecting means 18 and the second undulation. The undulation angle of each boom 3, 4 from the angular velocity detection means 23 is input, and the allowable maximum angular velocity of the work table 5, that is, the allowable maximum angular velocity “ωa” of the leveling cylinder 27 is input from the memory 13. Is done. The speed regulating means 24 calculates the angular velocity subtraction amount “ωx” of the undulation cylinders 17 and 22 to regulate the speed of the undulation cylinders 17 and 22 based on the input information. This is output to the subtracters 15 and 20. The calculation control of the speed regulating means 24 will be described based on the flowchart of FIG.
[0033]
3, after the control is started, the allowable maximum angular velocity “ωa” of the work table 5 (that is, the leveling cylinder 27) is first input from the memory 13 (step S1). The required angular velocities “ω1” and “ω2” of the hoisting cylinders 17 and 22 corresponding to the manipulated variables 11 and 12 are input (step S2), and the total value of the required angular velocities “ω1” and “ω2” “ In step S4, the allowable maximum angular velocity “ωa” and the total value “ωb” are compared, and when (“ωa”> “ωb”), When “normal operation” is determined, and (“ωa” <“ωb”), it is determined “abnormal operation”.
[0034]
If it is determined that “normal operation”, the angular velocity subtraction amount “ωx” of each of the undulating cylinders 17 and 22 is set to 0 (step S8). Therefore, the command values output from the first command value calculation means 14 and the second command value calculation means 19, that is, the required angular velocities “ω1” and “ω2” are not subtracted by the subtracters 15 and 20, respectively. The actual angular velocities “ωc1” and “ωc2” are input to the first undulation control valve 16 and the second undulation control valve 21 as they are.
[0035]
On the other hand, when it is determined that “at the time of abnormal operation”, first, a subtraction process of the total value “ωb” of the required angular velocities of the hoisting cylinders 17 and 22, that is, a certain amount from the total value “ωb”. The process of subtracting by the subtraction amount “ω0” is repeated until the total value after subtraction, that is, the subtraction total value “ωc” is equal to or lower than the allowable maximum angular velocity “ωa” (steps S5 and S6), and finally. A subtraction total value “ωc” is obtained.
[0036]
Next, the subtracted total value “ωc” is divided by the number of undulating cylinders (in this embodiment, each undulating cylinder 17, 22 is provided, so “2”). An angular velocity subtraction amount “ωx” is obtained (step S7).
[0037]
The angular velocity subtraction amount “ωx” obtained as described above is input from the speed regulating means 24 to the subtracters 15 and 20 as shown in FIG. The angular velocity subtraction amount “ωx” is subtracted from the required angular velocities “ω1” and “ω2” output from the 1 command value calculation means 14 and the second command value calculation means 19, respectively, and the value after the subtraction is the actual angular velocity “ωc1”. , “Ωc2” is output to the first undulation control valve 16 and the second undulation control valve 21.
[0038]
The first undulation control valve 16 and the second undulation control valve 21 are operated on the basis of the final actual angular velocities “ωc1” and “ωc2”, and the undulation cylinders 17 and 22 are expanded and contracted. The booms 3 and 4 are appropriately raised and lowered.
[0039]
In this case, the total value “ωc” of the actual angular velocities “ωc1” and “ωc2” is made equal to or less than the allowable maximum angular velocity “ωa” by subtracting the required angular velocities “ω1” and “ω2” in the subtracters 15 and 20. As a result, the speeds of the hoisting cylinders 17 and 22 are regulated, so that the required angular speed “ω1” of the hoisting cylinders 17 and 22 is controlled by the proximal boom hoisting operation lever 11 and the distal boom hoisting operation lever 12. ”And“ ω 2 ”, although each of the undulating cylinders 17 is in an“ over operation ”state in which the operation is performed such that the total value“ ωb ”exceeds the allowable maximum angular velocity“ ωa ”of the horizontal maintaining drive means 27. , 22 is ensured to follow the change in the angular velocity of the leveling cylinder 27 with respect to the change in the angular velocity of the leveling cylinder 27, and the work table regardless of whether the booms 3, 4 are raised or lowered. Its attitude is horizontally maintained constantly, but the reliability during aerial of using the work platform 5 is ensured.
[0040]
Second embodiment
FIG. 4 is a control block diagram of the leveling device for an aerial work vehicle according to the second embodiment. The control block diagram in the leveling device of this embodiment is basically the same as that of the leveling device in the first embodiment, and the difference is that
The leveling device according to the first embodiment includes subtracters 15 and 20 and, at the time of “abnormal operation”, the required angular velocities “ω1” and “ω2” from the first command value calculation means 14 and the second command value calculation means 19. However, in this embodiment, the multipliers 31 and 32 are provided in place of the subtracters 15 and 20, and the speed regulating means 24 in the first embodiment is In contrast to the configuration in which the subtraction amount “ωx” of the angular velocity is obtained, the velocity regulating means 24 of this embodiment is configured to obtain the correction coefficient “C” that is the basis of multiplication in the multipliers 31 and 32. The point
It is.
[0041]
Accordingly, only the configuration specific to this embodiment will be described here, and the description of the same configuration as in the first embodiment will be omitted by using the corresponding description in the first embodiment.
[0042]
First, a method of calculating the correction coefficient “C” in the speed regulating means 24 will be described based on the flowchart of FIG.
[0043]
5, after the control is started, first, the allowable maximum angular velocity “ωa” of the work table 5 (that is, the leveling cylinder 27) is input from the memory 13 (step S1), and the first command value calculation is performed. The required angular velocities “ω1” and “ω2” of the undulation cylinders 17 and 22 are input from the means 14 and the second command value calculating means 19 (step S2), and the required angular velocities “ω1” and “ω2”. In step S4, the allowable maximum angular velocity “ωa” is compared with the total value “ωb”, where (“ωa”> “ωb”). In some cases, “normal operation” is determined, and (“ωa” <“ωb”), and “abnormal operation” is determined.
[0044]
If it is determined that “normal operation”, the correction coefficient “C” for the angular velocity of the hoisting cylinders 17 and 22 is set to 1 (step S6). Accordingly, the required angular velocities “ω1” and “ω2” output from the first command value calculating means 14 and the second command value calculating means 19 are not corrected in the multipliers 31 and 32, but are directly applied to the actual angular velocities. “Ωc1” and “ωc2” are input to the first undulation control valve 16 and the second undulation control valve 21.
[0045]
On the other hand, when it is determined that “at the time of abnormal operation”, the correction coefficient “C” is obtained in step S5. That is, the allowable maximum angular velocity “ωa” is divided by the total value “ωb” of the required angular velocities “ω1” and “ω2” to obtain a correction coefficient “C = (ωA / ωb)”.
[0046]
As shown in FIG. 4, the correction coefficient “C” obtained as described above is input from the speed regulating means 24 to the multipliers 31 and 32, and each of the multipliers 31 and 32 receives the first coefficient. Each of the required angular velocities “ω1” and “ω2” output from the command value calculating means 14 and the second command value calculating means 19 is multiplied by the correction coefficient “C” to reduce this, and the actual angular speed “ωc1”, Let “ωc2”. Accordingly, since the total value “ωc” of the actual angular velocities “ωc1” and “ωc2” is equal to or less than the allowable maximum angular velocity “ωa”, the proximal boom raising / lowering lever 11 and the distal boom raising / lowering operation are performed. The lever 12 is operated so that the total value “ωb” of the required angular velocities “ω1” and “ω2” of the hoisting cylinders 17 and 22 exceeds the allowable maximum angular velocity “ωa” of the horizontal maintaining drive means 27. In spite of the above-mentioned operation time, the followability of the change in the angular velocity of the leveling cylinder 27 to the change in the angular velocity of the hoisting cylinders 17 and 22 is ensured, and the hoisting operation of the booms 3 and 4 is ensured. In any case, the work table 5 is always maintained in a horizontal position, and reliability at the time of working at a high place using the work table 5 is ensured.
[0047]
In this embodiment, the ratio “ωa / ωb” between the allowable maximum angular velocity “ωa” and the total value “ωb” is set as a correction coefficient “C”, and the request is made based on the correction coefficient “C”. The speeds of the hoisting cylinders 17 and 22 are regulated by correcting the angular velocities “ω1” and “ω2”. The correction by the correction coefficient “C” is performed by the required angular speeds of the hoisting cylinders 17 and 22, respectively. This means that “ω1” and “ω2” are proportionally distributed according to their sizes. Therefore, the angular speed of the hoisting motion of each of the booms 3 and 4 is smaller than originally planned. However, the booms 3 and 4 have relative undulation angular velocities as intended by the operator. For this reason, the operator has almost no sense of incongruity with respect to the raising and lowering operations of the booms 3 and 4, and the operability of the aerial work vehicle is maintained accordingly.
[0048]
Third embodiment
FIG. 6 is a control block diagram of the leveling device for an aerial work vehicle according to the third embodiment. The control block diagram in the leveling device of this embodiment is basically the same as that of the leveling device in the first embodiment, and is different from the first embodiment in the first embodiment. A command value for the leveling control valve 26 is calculated based on the detection values of the detection means 18 and the second undulation angular velocity detection means 23, and the detection value of the work table position detection means 28 is used as feedback control information of the posture of the work table 5. The third command value calculation means 25 is separated from the first undulation angular velocity detection means 18 and the second undulation angular velocity detection means 23, and the third command value calculation means 25 is separated from the work table position. The command value for the leveling control valve 26 is calculated based only on the detected value of the attitude of the work table 5 detected by the detecting means 28. It is in that form.
[0049]
In the case of such a configuration, the control system is simplified, and a cost reduction can be expected.
[0050]
In the third embodiment, the configuration of the first embodiment is used as a basis. However, the configuration is not limited to this. For example, the configuration of the second embodiment can be used as a basis. .
[0051]
Further, from the viewpoint of further simplifying the control system, for example, the first undulation angular velocity detection means 18 and the second undulation angular velocity detection means 23 are not provided, and the detection value of the workbench position detection means 28 is set to the first undulation angular velocity detection means 23. It is also possible to adopt a configuration in which the detected value is used for the calculation of the angular velocity subtraction amount “ωx” in the speed regulating means 24 as well as being input to the speed regulating means 24 together with the 3 command value computing means 25. Of course, this configuration can also be applied to the first and second embodiments.
[0052]
Other
(1) In each of the embodiments described above, two booms of the proximal boom 3 and the distal boom 4 are provided (that is, only the distal boom 4 is provided as the “next boom” in the claims). Although an aerial work vehicle is described as an example, the present invention is not limited to such a configuration, and can be applied to an aerial work vehicle having, for example, two or more booms as the next-stage boom. Of course.
[0053]
(2) In each of the above embodiments, the leveling cylinder 27 is used as an example of the horizontal maintenance driving means for driving the work table 5, but the present invention is limited to such a configuration. Instead, for example, a hydraulic motor or an electric motor can be employed as the horizontal maintaining drive means.
[Brief description of the drawings]
FIG. 1 is an overall view of an aerial work vehicle equipped with a leveling device according to the present invention.
FIG. 2 is a control block diagram of the leveling device according to the first embodiment of the present invention.
FIG. 3 is a control flowchart of the leveling device according to the first embodiment.
FIG. 4 is a control block diagram of a leveling device according to a second embodiment of the present invention.
FIG. 5 is a control flowchart of the leveling device according to the second embodiment.
FIG. 6 is a control block diagram of a leveling device according to a third embodiment of the present invention.
FIG. 7 is an overall view of an aerial work vehicle equipped with a conventional leveling device.
FIG. 8 is an overall view of an aerial work vehicle equipped with a conventional leveling device.
[Explanation of symbols]
1 is a vehicle, 2 is a swivel, 3 is a proximal boom, 4 is a distal boom, 5 is a workbench, 11 is a proximal boom raising / lowering operating lever, 12 is a distal boom raising / lowering operating lever, 13 is a memory, 14 is First command value calculation means, 15 is a subtractor, 16 is a first undulation control valve, 17 is a first undulation cylinder, 18 is a first undulation angular velocity detection means, 19 is a second command value calculation means, 20 is a subtractor, 21 is a second undulation control valve, 22 is a second undulation cylinder, 23 is a second undulation angular velocity detection means, 24 is a speed regulation means, 25 is a third command value calculation means, 26 is a leveling control valve, 27 is a leveling cylinder, Reference numeral 28 denotes a work table position detection means, and 31 and 32 denote multipliers.

Claims (2)

A proximal boom (3) is provided on the vehicle (1), and a next-stage boom is provided at the distal end of the proximal-end boom (3) so that the boom can be raised and lowered in sequence, and the most advanced boom (4) in the next-stage boom is provided. A work table (5) is attached to the front end of the boom so as to be swingable along the boom raising / lowering surface, and the raising / lowering cylinder (17) is provided between the vehicle (1) and the proximal boom (3) and between each boom stage. ), (22), and a horizontal sustaining drive means (27) is disposed between the state-of-the-art boom (4) and the workbench (5). A leveling device for an aerial work vehicle configured to maintain the work table (5) horizontally regardless of the swinging motion of the boom stage,
When the total value (ωb) of the required angular velocities (ω1), (ω2),... Of the undulating cylinders (17), (22) exceeds the allowable maximum angular velocity (ωa) of the horizontal maintaining drive means (27). The required angular velocity (ω1) so that the total value (ωc) of the actual angular velocities (ωc1), (ωc2),... Of the undulating cylinders (17), (22) is equal to or less than the allowable maximum angular velocity (ωa). , (Ω2),..., A leveling device for an aerial work vehicle characterized by comprising speed regulating means (24) that regulates. A proximal boom (3) is provided on the vehicle (1), and a next-stage boom is provided at the distal end of the proximal-end boom (3) so that the boom can be raised and lowered in sequence, and the most advanced boom (4) in the next-stage boom is provided. A work table (5) is attached to the front end of the boom so as to be swingable along the boom raising / lowering surface, and the raising / lowering cylinder (17) is provided between the vehicle (1) and the proximal boom (3) and between each boom stage. ), (22), and a horizontal sustaining drive means (27) is disposed between the state-of-the-art boom (4) and the workbench (5). A leveling device for an aerial work vehicle configured to maintain the work table (5) horizontally regardless of the swinging motion of the boom stage,
When the total value (ωb) of the required angular velocities (ω1), (ω2),... Of the undulating cylinders (17), (22) exceeds the allowable maximum angular velocity (ωa) of the horizontal maintaining drive means (27). Based on the ratio (ωa / ωb) between the maximum allowable angular velocity (ωa) and the total value (ωb), the actual angular velocities (ωc1), (ωc2) of the undulation cylinders (17), (22),. Is provided with speed regulating means (24) for regulating the required angular velocities (ω1), (ω2),... So that the total value (ωc) is equal to or less than the allowable maximum angular velocity (ωa). Leveling device for aerial work platforms.

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