JPH05317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a work control device for a telescopic aerial work vehicle.

[Technical background of the invention and problems in the background art]

The telescopic aerial work vehicle has an outrigger that supports the vehicle body, a swivel base that can rotate with respect to the vehicle body, and a telescopic boom that is pivoted on the swivel base so that the vehicle can be moved upwardly and upwardly by a hydraulic cylinder. , a basket attached to the tip of a telescoping boom, and the position of the basket can be changed by the rotation of a swivel base and the operation of a hydraulic cylinder, thereby facilitating the work of a worker riding on the basket.

Conventionally, in order to prevent such a high-altitude work vehicle from overturning, the boom angle and boom length have been detected, and the working range has been regulated based on this detection. However, with this type of regulation, the work range remains constant regardless of various other conditions such as the load on the basket. In other words, the work range was regulated based on the assumption that the basket carrying load was at its maximum. For this reason, when the carrying load is small, there is a problem in that work can only be done within a narrower range than is actually possible.

[Purpose of the invention]

An object of the present invention is to provide a control device for a vehicle for aerial work that can change the work regulation range according to various work conditions.

[Summary of the invention]

The control device of the present invention includes means for determining a critical overturning moment based on the amount of overhang of the outriggers and the turning angle of the swivel base, means for detecting the magnitude of the overturning moment currently acting on the telescopic boom, means for detecting the boom angle and boom length of the telescopic boom; means for calculating a dynamic overturning moment based on the detected boom angle and boom length; and the overturning moment currently acting on the telescopic boom and the calculation. means for determining the sum of the dynamic moments, and limiting means for prohibiting operation of the work vehicle in a direction in which the overturning moment increases when the sum exceeds the critical overturning moment; and means for generating an alarm when the sum is close to the critical overturning moment.

[Embodiments of the invention]

FIG. 1 shows an example of a telescopic aerial work vehicle that can be controlled by the control device of the present invention. As shown in the figure, this aerial work vehicle includes a vehicle body 1, outriggers 2 and 3 that are outside the wheels of the vehicle body 1 and for supporting the vehicle body more firmly, and a swivel base 4 that can rotate relative to the vehicle body 1. , a telescoping boom 5 which is pivotably supported on a swivel base 4 so as to be able to move up and down by a hydraulic cylinder 8 and extend and contract by a built-in telescopic cylinder 9; and a basket 7 attached to the tip of the boom 5. The position of the basket 7 is changed by the rotation of the swivel base 4 and the operation of the hydraulic cylinders 8 and 9, thereby facilitating the work of the worker riding on the basket 7. In addition, Outrigger 2,
The amount of lateral overhang of 3 can be adjusted to suit the conditions of the work site. Reference numeral 13 denotes a lifting device called a sub-crane, which is used for hoisting equipment associated with work at heights. Further, reference numeral 14 denotes a cradle, which is used to tighten and hold the boom 5 when not in operation.

FIG. 2 shows the drive system, where the sub-crane motor 16 and the swivel motor 17 are both hydraulic motors, and the sub-crane 13 and the swivel motor 17 are hydraulic motors, respectively.
It is used to drive the swivel base 4. These motors 1
Hydraulic pressure is supplied from the hydraulic pump 18 to the cylinders 8 and 9 that raise and lower the telescopic boom 5 and the cylinders 6 and 17, respectively. Manual valve 19
is operated by the sub-crane operating lever 20. The solenoid valve 21 receives the signal 34i from the control device CA.
The sub-crane operation signal 21i is supplied via the switch 34, which is closed by the sub-crane operating signal 21i. The electromagnetic proportional valves 22, 23, 24 are operated by drive signals supplied from electromagnetic valve amplifiers 25, 26, 27 via switches 28-33, respectively. The switches 28 to 34 each receive an activation signal 28i, which will be described later.
~34i. Reference numeral 35 is a swivel base operation lever, and the direction of rotation of the swivel base 4 (clockwise or counterclockwise) is designated by the direction in which the lever is tilted. 3
Reference numerals 6 and 37 are elevation and telescopic cylinder operation levers, respectively, and the direction of movement of the boom (elevation, extension and contraction) is designated by the direction in which they are tilted. Operation lever 35, 3
6 and 37, electric signals with different contents depending on the specified direction of movement are sent to the electromagnetic valve amplifiers 25 to 27.
supplied to

The switch 38 is a switch that is closed when using a sub-crane.
When the switch 34 is closed, a signal 38a is input to the control device CA, and a signal 34i closes the switch 34. As a result, the solenoid valve 21 can be operated. As described below, when the overturning moment becomes excessive, the switch 34 opens (trips).

FIG. 3 shows a part of the control system that is particularly concerned with regulating the work range. In the same figure,
DP is a data processing section, and this section can be mainly formed by a computer, for example a microcomputer. As shown in the figure, this data processing unit includes a central processing unit CPU, a fixed storage device
Consists of ROM, constant speed access memory RAM, signal input port IP, and output port OP. The functions of the data processing unit are shown in Figure 4, and will be described in detail later, but generally it performs arithmetic processing based on each signal input connected to the signal input port IP, and regulates according to the work status. Determine whether the conditions are met and issue a warning depending on the determination result.
It also restricts movement.

BA is a boom angle detector that detects the boom angle (elevation angle of the boom relative to the horizon) of the telescopic boom.
As shown in FIG. 1, it is attached to a telescopic boom and consists of a potentiometer that generates a voltage signal depending on the boom angle. For example, the boom angle detector BA for a telescopic boom is designed to detect boom angles in the range of 0 to 80 degrees. BL is a boom length detector that detects the boom length of a telescopic boom.As shown in Figure 1, it is attached to the telescopic boom and generates a wire and wire drum that extend according to the boom length and a voltage signal according to the rotation of the drum. It consists of a potentiometer (multi-rotation type) that generates . For example, the boom length detector BL is designed to detect a range of 0 to 6 m.

MS is a falling moment detector that generates a voltage signal according to the moment of the telescopic boom 5. As this moment detector, the one disclosed in the application for utility model registration dated October 30, 1982 by the present applicant can be used. Hereinafter, the details will be described together with the details of the structure of the swivel base with reference to FIGS. 5 to 9.

First, in these figures, the reference numeral 1a indicates the vehicle body 1.
A lower base 4a of a swivel table 4 is mounted on this frame 1a via a swivel ring 1b so as to be able to rotate around a vertical axis. On this lower base 4a is a three-point support mechanism 4b, which will be described later.
An upper base 4c is mounted thereon. Above this upper base 4c, a telescopic boom 5 is mounted on a pivot shaft 5.
The boom 5 is pivoted so as to be able to rise and fall around the boom 5, and a hydraulic cylinder 8 is installed between the middle of the boom 5 and the upper base 4c. This hydraulic cylinder 8 is of a one-sided rod type, and one end of the cylinder 8a is connected to the upper base 4c via a pin 8c, while the tip of the rod 8b is connected to the side of the boom 5 with a pin 8d. Connected via pin.

Next, the configuration of the three-point support mechanism 4b described above will be explained.

The upper base 4c is composed of two side plates 4d, 4d arranged in parallel, and a cross beam 4e spanned in the horizontal direction to connect these side plates. Brackets 4f, 4f are integrally projected from the rear end of the lower surface.
Each bracket 4f is bifurcated and connected to a bracket arm 4g projecting from the lower base 4a with a pin 4h. A pair of these pins 4h are spaced apart on the same axis and constitute a pivot shaft between the lower base 4a and the upper base 4c.

On the other hand, on the front surface of the cross beam 4e of the upper base 4c, brackets 4i, 4i are provided to protrude forward, and a pin-shaped load cell 4j is stretched between the tips of the brackets 4i, 4i. As is clear from FIG. 9, this pin-shaped load cell 4j has strain gauges 4k at several locations on the surface of the pin.
A bridge circuit is constructed by using this voltage, and the moment can be detected using the voltage. The pin-shaped load cell 4j is
Its central portion is supported by a spherical bearing 4m, which is accommodated in a bearing hole 4n of the lower base 4a. The spherical bearing 4m consists of an inner race 4p and an outer race 4q that are combined so that they can make spherical contact. As a result of this configuration, the two pins 4h, 4h and the pin-shaped load cell 4j are respectively arranged at positions corresponding to the vertices of an isosceles triangle drawn on a plane, forming a so-called three-point support mechanism. are doing.

With this configuration, as shown in FIG. 10, the moment M acting on the telescopic boom 5 causes a downward force to act on the load cell 4j. As a result, although the load cell 4j itself generates a voltage signal according to the force, the distance L from the pivot point
is constant, the output of the load cell 4j depends on the moment.

Returning to Figure 3, the outputs of boom angle detector BA, boom length detector BL, and moment detector MS are sent to the A/D converter via multiplexer MPX.
It is supplied to the ADC and converted into a 256-value digital signal. , multiplexer MPX output port
Multiplexer selection signal output from OP
Controlled by MPXS, three inputs are sequentially selected and output.

LS1 and LS2 are limit switches, and these two
The two limit switches are attached to the lower part of the swivel base 4 as shown in Fig. 11a, and work together with cams CM1 and CM2 provided on the vehicle body 1 side to keep the turning angle ranges TA1 and TA2 in Fig. 12, respectively. It is designed to operate (close) when . From the output signals of these two limit switches, it can be determined whether the turning angle of the turning table is within the range of TA1, within the range of TA2, or outside the range of TA3 (within the range of TA3). Therefore, the lit switches LS1 and LS2 are referred to as turning angle detection sections. In this example, the turning angle is TA
Depending on whether the vehicle is in TA1, TA2, or TA3, the appropriate critical overturning moment is calculated for each. This is because the limit value differs depending on the direction of the moment (front, rear, or side of the vehicle body).

Like the limit switches LA1 and LS2, LS3 is also installed at the bottom of the swivel base to detect the turning angle and works with a cam (not shown) on the vehicle body 1 side. In FIG. 12, it operates (closed) when it is within the range of TB1, and is open otherwise (when it is within the range of TB2). The detection result by the limit switch LS3 is used to restrict the turning direction when the overturning moment is excessive, as will be described later. That is, when within the range of TB1, only clockwise turning (as shown in FIG. 12) is permitted, and when within the range of TB2, only counterclockwise turning is permitted. This is because turning in that direction makes it less likely to fall. Incidentally, the turning angle may be detected not by a limit switch but by an angle detector TAD using a potentiometer or the like as shown in FIG. 11b. In this case, a voltage signal is generated depending on the turning angle. This output is supplied to an A/D converter ADC via a multiplexer MPX. This allows TA
1. Detect the turning range of TA2, TA3, TB1, and TB2.

In Fig. 12, the dashed-dotted line LNG represents the center of the vehicle body along the direction of travel of the vehicle body, and TA1 is, for example, a range of approximately 30° centered on the center line LNG,
TA2 is, for example, a range of about 50° centered on the center line LNG. Further, TB1 is an angle range between the center line LNG and the line WDT in the width direction of the vehicle body 1 perpendicular to the center line LNG.

Returning to Figure 3 again, RL1a to RL1d and
RL2a to RL2d have outriggers 2a to 2, respectively.
This is a limit switch provided corresponding to d to detect the amount (state) of the corresponding outrigger being extended. The limit switches also do not operate, and only RL1a to RL1d operate from 1/2 to just before the maximum (most extended state), and both operate at the maximum. In addition, when the overhang amount differs among the four outriggers, in order to determine the regulation range etc. according to the state of the smallest outrigger, four limit switches RL1a to RA1d are set respectively.
and RL2a to RL2d are connected in series to perform AND (logical product).

Referring to Figure 4 below, data processor DP
The contents of the arithmetic processing will be explained below. Furthermore, input port
Signals input through IP are stored in memory.
It is input to RAM, but I will omit that point in the explanation.

The limit overturning moment setting unit LOTM receives the signal TURN from the turning angle detection units LS1 and LS2, and the signal indicating the outrigger extension amount, that is, the limit switch.
Signals from RL1a to RL1d, RL2a to RL2d
After receiving OUTR, set the limit overturning moment LOTM. The calculation for this setting is based on a well-known formula. The turning angle and the amount of outrigger extension are not detected as continuous quantities, but only detect which of several ranges they fall within, so the conditions that are most likely to tip over within that range are assumed. Calculate the critical overturning moment. When detecting the turning angle with an angle detector (potentiometer), the output is a continuous voltage, but the microcomputer processes it depending on whether it falls within each range, so the same method as above is used. Calculate the critical overturning moment based on this concept.
Note that this calculation may be performed by inputting the input variable into the memory as address information and outputting the contents of the address as the calculation result. That is, a part of the memory ROM is configured in a table shape,
The function (calculation result) may be stored in an address corresponding to each variable, input signals (data) may be combined to create address information, and the function (count result) may be read from the address. Such a method can also be applied to various other calculations described below.

The static overturning moment calculation unit SOTM receives the absolute value MABS from the overturning moment detection unit MS, removes the harmonic component from it to remove the dynamic component, and calculates the static overturning moment SOTM.

The dynamic overturning moment calculation unit DOTM calculates the dynamic overturning moment DOTM based on the data BAN indicating the boom angle and the data BLE indicating the boom length. Dynamic overturning moment is the overturning moment caused by the inertial force that acts when starting and stopping the boom, etc., and the wind (assuming up to 16 m/sec).
The dynamic overturning moment (planned or maximum value to be considered) at a predetermined boom angle can be calculated by, for example, Methods stipulated in vehicle safety standards (voluntary standards) can be used. In this case, in this embodiment, the weight of the basket is the value at the time of maximum loading, and is calculated assuming that it is constant.

The total overturning moment calculation unit TOTM combines the static overturning moment SOTM calculated by the static overturning moment calculation unit SOTM and the dynamic overturning moment calculation unit
Dynamic overturning moment calculated by DOTM DOTM
Add these to find the total overturning moment TOTM.

The comparison calculation unit CMP compares the total overturning moment TOTM calculated by the total overturning moment calculation unit and the limit overturning moment LOTM calculated by the limit overturning moment setting unit, and determines that TOTM is sufficiently smaller than LOTM, for example, less than 70%. Or close to LOTM,
For example, different signals (data) are generated depending on whether it is 70% or more and less than 100% or LOTM or more.

The comparison calculation unit CMP also calculates the ratio (percentage) of TOTM to LOTM and displays it in the data display unit DD.
(Figure 3) displays the numerical values.

The no-turn area detection unit NTURN is the turning base angle.
Based on TURN and boom angle BAN, it is determined whether the swivel base is within the no-turn area.
That is, if the turning angle is within the angle range TA1 in FIG.
Moreover, it is determined whether the boom angle BAN is less than a predetermined value. In front of the swivel base, there is a lower boom cradle 14 as shown in Figure 1, which allows for a low boom angle.
When turning with BAN, the vehicle hits the cradle 14, its stopper, and the cab of the vehicle, so to avoid this, the above-mentioned determination is made. still,
Regarding the turning angle, it is not necessary to determine whether or not it is within the range of TA1, but it may be set to a range that exactly matches the width of the cradle 14, but as in this embodiment, if the determination is made as to whether or not it is within the range of TA1, the limit switch LS1
can be shared.

The comprehensive judgment unit SYN uses the comparison result in the comparison calculation unit CMP and the inside/outside no-turning area judgment unit.
Based on the results of the determination in NTURN, a comprehensive determination of the state is made and a drive control signal is generated for each drive system. It also controls indicator lights and buzzers.

That is, normally, a signal is supplied to the switches 28 to 34 to close the switches in order to enable the operation of each operating part, and accordingly, each operating part (excluding the sub-crane) is closed. Corresponding indicator light
Although PL1 to PL6 are lit, if it becomes necessary to prohibit the operation of some or all operating parts,
Open the switch and make it inoperable.

It also sounds the alarm buzzer BZ and controls the flashing of the caution indicator PWN and stop indicator PST.

FIG. 14 is a flowchart showing the operation of the data processing section as described above.

First, a determination 101 is made as to whether or not it is possible to turn. This determination corresponds to the operation of the turning prohibition detection unit NTURN shown in FIG. 4, and the details are shown in FIG. 15. That is, first, the turning angle is read (201).
Next, it is determined whether this turning angle is a predetermined value, that is, whether it is within the range of TA1 in FIG. 12 (202). If it is not within the range of TA1, the determination result indicating that the turn is possible is stored and input into, for example, a memory RAM) (203) and this routine is terminated.
If it is within the range of TA1, the first boom angle is input (204), and it is determined whether it is larger than a predetermined angle BAK (205). If it is larger, the process proceeds to step 203; if it is not larger, the judgment result that turning is not possible is stored (for example, inputted into the memory RAM) (206), and this routine is ended.

Next, depending on the result of the determination of whether or not it is possible to turn (10
2) If the rotation is possible, enable the solenoid valves 22 to 24 (by closing the switches 28 to 33) (10
3). The solenoid valve 21 is enabled or disabled depending on whether the sub-crane use switch 38 is opened or closed. When using the sub-crane (switch 38 closed), switch 34 is also closed.
Therefore, the solenoid valve 21 is also in an operable state. If turning is not possible in step 102, the turning solenoid valve is made inoperable (switches 28 and 29 are opened), and the other electromagnetic valves are made operable (switches 30 to 34 are closed) (104).

Next, enter data indicating the amount of outrigger extension and data indicating the swivel base angle (10
6,107). Then, based on these, address information of the limit overturning moment data table is created (108), and the contents of the address are read out as the limit overturning moment LOTM under the conditions (109). The above operations (106 to 109) are the fourth
This corresponds to the operation of the limit overturning moment setting unit LOTM in the figure.

Next, input the boom angle BAN and boom length BLE of the telescopic boom (110, 111), create the address information of the dynamic overturning moment data table based on these (112), and input the contents of the address under the conditions. It is read out as the dynamic overturning moment at the bottom (113). On the other hand, the moment (static moment) detected by the moment detector and from which harmonics have been removed is input (114), and the moments obtained in steps 113 and 114 are added together to obtain the total overturning moment ( 115). The above operation is performed by the block in Figure 4.
Compatible with DOTM, SOTM, and TOTM operations.

Next, the ratio (percentage) between the total overturning moment TOTM determined in step 115 and the limit overturning moment LOTM determined in step 109 is determined (11
6). This ratio is then digitally displayed on the display section DD (117). Then this ratio is, for example, 70
It is determined whether the value is smaller than % (118).
If it is smaller, that is, if the total overturning moment TOTM is sufficiently smaller than the limit overturning moment LOTM, the process returns to step 101 and the above operation is repeated. If it is larger, then it is determined whether the ratio is smaller than 100% (119), and if it is smaller, all switches 28 to 34 are kept closed.
Thereby, the electromagnetic valves 22 to 24 remain operable. The solenoid valve 21 is enabled or disabled by opening and closing the sub-crane use switch 38 (122). An alarm output is generated, that is, the alarm indicator lamp is made to blink and an alarm buzzer is sounded (123), and the process returns to step 101. That is, if the total overturning moment does not reach the critical overturning moment but is close to it (for example, 70% or more), an alarm is output, but the work is allowed to continue.

If it is 100% or more in step 119, then
A signal from the switch 38 indicating whether or not to use the sub-crane 13 or operating the solenoid valve 21 is read (120), and it is determined whether to use it (121). If it is to be used, open the switches 28 to 34 to disable all solenoid valves (124) (this will prevent the boom, etc. from operating even if the operator operates the control lever of the boom, etc.) and stop the work. The stop indicator light is flashed and an alarm buzzer is sounded (125). Then, the process returns to step 106. That is, wait until the total overturning moment TOTM is reduced by lowering the suspended cargo by lowering the sub-crane, or until the sub-crane becomes unused by operating the switch 38.

The following describes how to release the overload condition (total overturning moment is excessive) by lowering the sub-crane. Move the sub-crane operating lever 20 (second
Figure) When the lowering operation is performed, the spool part 19a of the manual valve
The limit switch L20 (lowering switch) attached to the sub-crane motor operates, the sub-crane motor solenoid valve 21 operates, and the sub-crane motor 16 rotates in a direction to lower the sub-crane. There, the sub-crane can be lowered and the cargo can be unloaded.

On the other hand, when the sub-crane is not used in step 121, an overload prevention control routine is executed. In other words, the direction in which it can be turned (limit switch LS3
or the output of the turning angle detector TA) are inputted (134,
135), creates solenoid valve control data table address information based on these (136), and reads out the contents of the address as solenoid valve control data (136).
37), outputs the solenoid valve control data to control the solenoid valve (138), flashes the stop indicator light, and sounds the alarm buzzer (138).
39), return to step 106.

The contents of the control of the electromagnetic valve with respect to the turning direction etc. are as shown in the table of FIG. In the same table, TB1,
TB2 represents data representing the turning angle (therefore, the direction in which turning is allowed), and "inside" and "outside" represent data representing inside and outside of the no-turning area. Further, ◯ and × represent whether or not each operating section is operated, that is, whether the switches 28 to 33 are on or off. The basic idea adopted here is that the solenoid valve can be operated to move the swivel platform and boom in a direction that reduces the overturning moment.
The purpose is to prohibit the operation of solenoid valves that move the swivel base and boom in a direction that increases the overturning moment.

〔Effect of the invention〕

As described above, according to the present invention, the critical overturning moment is determined based on the overhang amount of the outrigger and the turning angle of the swivel base, and the overturning moment acting on the telescoping boom, the boom angle, and the boom length are The system calculates the sum of the dynamic overturning moment obtained based on the above-mentioned dynamic overturning moment, and when this sum reaches a value close to the critical overturning moment, an alarm is issued and the operation of the work vehicle is restricted. The work area can be expanded to the maximum extent, improving work efficiency and safety.

Further, according to the present invention, since the operation of the work vehicle in the direction in which the critical overturning moment increases is prohibited, the safety against overturning is further improved, and the operation in the direction in which the overturning moment does not increase is possible. Therefore, work efficiency is improved.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing an example of an aerial work vehicle, Figure 2
The figure shows the piping and wiring diagram showing the drive system, Fig. 3 is a block diagram showing the hardware configuration of the control system, Fig. 4 is a functional block diagram showing the functions of the data processing section, and Fig. 5 shows the swivel table in detail. 6 is a side view of the swivel base, FIG. 7 is a rear view of the swivel base, FIG. 8 is a front view of the swivel base, FIG. 9 is a sectional view showing the load cell section of the swivel base, and FIG. Figure 10 is an explanatory diagram of the direction of the overturning moment, Figures 11a and b are schematic diagrams showing the detection unit for the rotation angle of the swivel base, Figure 12 is an explanatory diagram of the rotation angle of the swivel base, and Figure 13 is a diagram illustrating the rotation angle of the swivel base. Explanatory diagram of the amount of outrigger overhang, Figure 14a~
d and FIG. 15 are flowcharts showing the operation of the data processing section, and FIG. 16 is a chart showing the control contents. BA...Boom angle detector, BL...Boom length detector, LS1, LS2, LS3...Turning angle detection limit switch, RL1a to RL1d, RL2a to RL2d...
Outrigger extension amount detection limit switch, BZ
...Alarm buzzer, PWN...Caution indicator light, PST...Stop indicator light, 28-33...Switch, DP...Data processing unit, NTURN...No-turning area detection unit, LOTM
…Limit overturning moment setting unit, DOTM…Dynamic overturning moment calculation unit, SOTM…Static overturning moment calculation unit, TOTM…Total overturning moment calculation unit,
CMP...comparison calculation section, SYN...comprehensive judgment section.

Claims (1)

[Scope of Claims] 1. An aerial work vehicle having an outrigger that supports a vehicle body, a swivel base that is rotatable with respect to the vehicle body, and an extendable boom that is pivotally supported to the swivel base so as to be able to move up and down. means for determining a critical overturning moment based on the amount of overhang of the telescopic boom and the rotation angle of the swivel base; means for detecting the magnitude of the overturning moment currently acting on the telescopic boom; and the boom angle of the retractable boom and the boom. means for detecting the boom length; means for calculating a dynamic overturning moment based on the detected boom angle and boom length; and a means for calculating a dynamic overturning moment based on the detected boom angle and boom length; means for determining the sum; limiting means for restricting the operation of the work vehicle in a direction in which the overturning moment increases when the sum exceeds the overturning limit; and An aerial work vehicle control device comprising means for generating an alarm when the moment is close to the moment. 2. The telescoping boom is driven by a hydraulic cylinder to perform the elevating motion, and the means for detecting the overturning moment currently acting on the telescoping boom detects the force transmitted from the telescoping boom to the rotating base via the hydraulic cylinder. 2. The device according to claim 1, further comprising a load cell that detects a force corresponding to the load cell.