JPH0550440B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Industrial Application Field) The present invention relates to a position control device for a work platform of an aerial work vehicle, and more specifically, to an abnormal output of a control lever for controlling the position of the work platform. This relates to a safety feature that prevents abnormal operation of the underlying workbench.

(Prior art) Conventionally, the position control of the work platform of an aerial work vehicle was performed using the fifth
As shown in the figure, the operation is performed based on the operation of a control lever 1, and the amount of the operation is converted into voltage by a potentiometer 2 and output. Then, the output voltage 1 is compared with a preset reference voltage Es by the comparator 3, and based on the comparison value, the amount of movement of the workbench is calculated by the calculating section 5 and output.

In such a control device, the output of the comparator 3 is set to 0 when the control lever 1 is not operated, that is, in the neutral position.
The output needs to stop the workbench. For this purpose, a trimmer 4 is connected to the reference voltage input terminal of the comparator 3, and the trimmer 4 outputs the reference voltage.
Es was initially set to match the output voltage of the potentiometer 2 when the control lever 1 was in the neutral position.

(Problem to be Solved by the Invention) However, in the above-described control device, if an abnormal output exceeding the output range of the potentiometer 2 due to a failure occurs in the potentiometer 2, However, there was a problem in that an output signal was output from the calculation unit 5 in response to the abnormal output, and the workbench was moved.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a swivel base that is rotatably mounted on the vehicle body frame, and a boom that is capable of raising and lowering and extending and retracting the swivel base. A workbench is provided at the tip of the boom, and an operating lever is provided to move the workbench to a desired position.
In the aerial work vehicle, the control lever is equipped with a control device that outputs the amount of operation thereof by a potentiometer, and outputs an output signal for moving the work platform based on the output of the potentiometer. a setting means capable of selectively initializing neutral position data corresponding to the neutral position of the operating lever and maximum and minimum position data corresponding to the operating area of the operating lever; Storage means for storing neutral position data and maximum and minimum position data, and whether output data of a potentiometer based on operation of an operating lever is within the range of maximum and minimum position data stored in said storage means. a discriminating means for discriminating;
Control means for outputting neutral position data stored in the storage means as output data of the potentiometer based on the output of the discrimination means when the output data of the potentiometer is outside the range of the maximum and minimum position data. and is included in the position control device for the workbench.

(Function) With the above configuration, when the setting means is operated, the output data of the potentiometer and the like corresponding to the neutral position of the operating lever are initialized, and each of these initial setting values is stored in the storage means. Then, the output data of the potentiometer resulting from the operation of the operating lever is compared with the maximum and minimum data stored in advance in the storage means, and if it is outside the range, the data is replaced with the output data of the potentiometer and stored in the storage means. Since the amount of movement of the workbench is calculated based on the neutral position data, the workbench is stopped.

(Example) Below, examples embodying this invention are shown in Figures 1 to 1.
This will be explained according to FIG.

As shown in FIG. 2, in the aerial work vehicle 11, a swivel base 14 is attached to a swivel seat bearing 13 provided on a body frame 12 so as to be horizontally swivelable. 13
A hydraulic swing motor 15 is provided for driving the swivel base 14, and the swivel base 14 is swiveled by the operation of the motor 15.

The base end of the outer boom 16 is supported on the swivel base 14 so as to be able to rotate up and down, that is, to be able to raise and lower.
A hoisting cylinder 17 is provided between the outer boom 16 and the swivel base 14, and the hoisting cylinder 1
7, the outer boom 16 is raised and lowered.

An inner boom 18 is supported on the tip side of the outer boom 16 so as to be retractable, and the inner boom 18 is extended and retracted by a telescoping cylinder (not shown) provided in the outer boom 16 to extend and retract from the outer boom 16. There is.

A workbench 19 is connected and held at the tip of the inner boom 18, and a first control panel 20 is provided on the workbench 19. As shown in FIG. 1, the control panel 20 includes a hoisting operation lever 21 for adjusting the hoisting angle of the outer boom 16, a telescoping operation lever 22 for adjusting the amount of extension and contraction of the inner boom 18, and a rotation angle of the swivel base 14. A swing operation lever 23 for adjusting the height, a traveling operation lever 24 for moving the aerial work vehicle 11, and the like are provided. These operating levers are in a non-operated state as a neutral position, and can be operated from the neutral position to both sides, that is, to the plus side and to the minus side. And each operating lever 2
Output signals based on the operations of 1, 22, 23, and 24 are output to a control device disposed within the swivel base 14.

A second control panel 25 is provided on the side surface of the swivel base 14, and each of the operating levers 21, 2
An operation switch 35 corresponding to 2 and 23 is provided, and the same operation as the first control panel 20 is possible.

Next, the electrical configuration of the control device will be explained with reference to FIG. 1.
The manipulated variables 23 and 24 are converted into voltages and outputted by potentiometers 26, 27, 28, and 29, respectively, and the output signals are outputted to an A/D converter 31 via a multiplexer 30. The multiplexer 30 selects a predetermined one from among the outputs of each potentiometer based on a command from a CPU 33 (described later), and outputs the selected output to an A/D converter 31. Then, the A/D converter 31 converts the analog value output from the multiplexer 30 into a digital value and passes it through a parallel input/output circuit (hereinafter referred to as PIO) 32 to a central processing unit (hereinafter referred to as CPU) as a discrimination means and control means. )
33 respectively.

In addition, PIO32 has potentiometers 2 corresponding to the neutral position of each operating lever and both ends of the operating area.
A setting switch 34 as a setting means for storing the output data of 6, 27, 28, 29 in a non-volatile memory 40 described later and the operation switch 35 for operating this aerial work vehicle 11 are connected. Said first control panel 20
It is set in. The program memory 36 connected to the CPU 33 is composed of a read-only memory (ROM), and programs for operating the CPU 33 are stored in advance.
3 operates based on that program. and,
The CPU 33 has the operating levers 21, 22, 23,
24 in this order, and based on the numbers, select and read out the output signal of each operating lever via the multiplexer 30, and based on the output signal, the rotation angle of the swivel base 14, The angle of elevation of the outer boom 16, the amount of expansion and contraction of the inner boom 18, etc. are calculated.

A RAM 37 connected to the CPU 33 is a writable and readable memory, and is designed to temporarily store calculation data output from the CPU 33. Then, the CPU 33 sends an output signal corresponding to each operating lever to the PIO 32 based on the calculated data.
The signal is output to the D/A converter 38 via the D/A converter 38. Then, the D/A converter 38 converts the digital value output from the PIO 32 into an analog value and outputs it to the drive amplifier 39, and the output of the drive amplifier causes the booms 16 and 18 to rise and fall, extend and contract, and the swivel base 14
The work platform 19 is moved by turning or by running the aerial work vehicle 11.

A nonvolatile memory 40 as a storage means also connected to the CPU 33 is a memory that can retain its stored contents even when the power is turned off.By initial setting using the setting switch 34,
Potentiometer 2 operated by each operating lever
Neutral position data of 6, 27, 28, and 29, plus side maximum data, and minus side maximum data are stored in advance. The CPU 33 controls each potentiometer 26 by operating each operating lever.
The output data of 27, 28, and 29 are sequentially read out in a time-sharing manner and temporarily stored in the RAM 37, and the output data is compared with the maximum data on the plus and minus sides stored in advance in the nonvolatile memory 40 to output the potentiometer. It is now possible to detect abnormal output.

Similarly, a 7-segment light emitting diode 41 (hereinafter referred to as LED) is connected to the CPU 33 and serves as a display means.
) are provided on the first and second control panels 20 and 25, respectively, and display operating lever numbers 1 to 4 based on the output of the CPU 33. In addition to LED, the display method is
It can also be configured using CRT, liquid crystal, light bulb, etc.

Next, the operation of the control device configured as described above will be explained with reference to FIGS. 3 and 4.

Now, when the engine of this aerial work vehicle 11 is started and the operation of each operating lever 21, 22, 23, 24 is started, the power is turned on to the control device.
The CPU 33 erases the memory contents of the RAM 37 (STEP 1, hereinafter referred to as S), outputs a signal to the multiplexer 30, first inputs the output data from the luffing operation lever 21, and stores it in the RAM 37 (S2). Check whether the output data is abnormal (S3). The contents of the abnormality check will be explained with reference to FIG.
It is determined whether or not the output data is within the range of the positive side maximum data and the negative side maximum data of 1 (S4, S5), and if it is within the range, the boom 1
6 and 18 are calculated and output (S8), and if they are outside the range, the LED 41 displays "1", which is the number corresponding to the undulation operation lever 21 (S6), and the data is stored in the non-volatile memory 40. The neutral position data of the luffing operation lever 21 stored in the controller is read out (S7), and the luffing angles of the booms 16 and 18 are calculated and output based on the data (S8). That is, when output data within the normal range is output from the potentiometer 26 of the hoisting control lever 21, the boom 1 is adjusted based on the amount of operation of the same control lever 21.
6 and 18 are raised and lowered, and the output data of the potentiometer 26 becomes abnormal for some reason, the boom 1
The ups and downs of 6 and 18 are stopped.

In this way, each operating lever 22, 23, 2
The output data of No. 4 is sequentially input to the CPU 33, and after it is determined whether or not it is an abnormal output, the output data is calculated as a drive amount and output (S9 to
S17). Then, such an operation is repeated, and the output of each operating lever is always checked by the CPU 33 and then calculated as a drive amount and output.

Therefore, in this control device, the CPU 33 can detect abnormal output due to failure of the potentiometer of each operating lever, and prevent abnormal output to the drive amplifier 39, thereby preventing abnormal operation of the workbench 19. be able to. Further, since the LED 41 displays the number corresponding to the operating lever in which the abnormality has occurred, the location of the failure can be easily found. In addition,
Even if the operating lever provided on the workbench 19 breaks down, the workbench can be moved by the operation switch provided on the swivel base 14.

Moreover, since the neutral position data and plus side and minus side maximum data of each operating lever 21, 22, 23, 24 stored in the non-volatile memory 40 are initialized by operating the setting switch 34, each operating lever Even if the potentiometers 21, 22, 23, 24 or the potentiometers 26, 27, 28, 29, etc. are replaced, each necessary data can be newly initialized with a simple setting operation.

Effects of the Invention As detailed above, according to the present invention, even if the operating lever or potentiometer is replaced, each necessary data such as the neutral position data of the operating lever can be newly initialized by simply operating the setting means. The present invention has the excellent effect of providing a work platform position control device for an aerial work vehicle that can improve safety by preventing abnormal operation due to failure of a potentiometer operated by a control lever. Demonstrate.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the electrical configuration of the workbench position control device, Figure 2 is a side view of the aerial work vehicle,
3 and 4 are flowcharts showing the operation of the central processing unit (CPU), and FIG. 5 is an electrical circuit diagram showing a conventional position control device. A raising/lowering operation lever 21, a telescopic operation lever 22, a turning operation lever 23, a travel operation lever 24, potentiometers 26, 27, 28, 29, a CPU 33 as a determining means and a control means, and a non-volatile memory 40 as a storage means.

Claims (1)

[Scope of Claims] 1. A swivel base is provided on the vehicle body frame so as to be rotatable, a boom is provided on the swivel base and can be extended and retracted, and a work platform is provided at the tip of the boom,
A control lever is provided to move the workbench to a desired position, and each control lever outputs the amount of operation by a potentiometer, and outputs an output signal to move the workbench based on the output of the potentiometer. In an aerial work vehicle equipped with a control device, the potentiometer is selectively provided with neutral position data corresponding to a neutral position of the operating lever, and maximum and minimum position data corresponding to the operating range of the operating lever. a setting means that can be initially set; a storage means for storing neutral position data and maximum and minimum position data initialized by the setting means; and output data of the potentiometer based on the operation of the operating lever is stored in the storage means. a determining means for determining whether or not the output data of the potentiometer is within the range of the stored maximum and minimum position data, based on the output of the determining means when the output data of the potentiometer is outside the range of the maximum and minimum position data; A position control device for a work platform in an aerial work vehicle, comprising: control means for outputting neutral position data stored in the storage means as output data of a potentiometer.