JP4177919B2 - Platform leveling device for aerial work platforms - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used for an aerial work vehicle having a workbench attached to the tip of a boom whose posture can be freely changed by hoisting or bending, and swinging in the vertical direction. The present invention relates to a leveling device that is kept horizontal.
[0002]
[Prior art]
As shown in FIG. 2, the aerial work vehicle has a boom 3 attached to a swivel 2 that is slidably mounted on the vehicle 1, and a work table 4 that can swing up and down at the tip of the boom 3. It is attached. The boom 3 may be one that does not bend or stretch, or one that can bend or stretch in the middle. In FIG. 2, the boom 3 is composed of a lower boom 3 a whose base end portion is attached to the swivel base 2 so that it can be raised and lowered, and an upper boom 3 b whose base end portion is attached to the distal end portion of the lower boom 3 a. This is shown as a bent-bend boom.
[0003]
A leveling device is attached between the tip of the boom 3 (tip of the upper boom 3b) and the work table 4 to maintain the work table 4 horizontally regardless of whether the boom 3 is raised or lowered. This leveling device includes a swing actuator 5 for swinging a work subject in the vertical direction, a drive control means 6 for controlling the drive of the swing actuator 5, and a leveling control means 7 for operating the drive control means 6 (FIG. 3). As shown in FIG. 3, the leveling control means 7 includes a boom attitude detection means 8 that detects the attitude of the boom 3, a swing angle detection means 9 that detects the inclination of the work table 4 with respect to the tip of the boom 3, and both of these detections. A control signal output unit 10 that calculates and outputs a control signal for maintaining the ground posture of the work table 4 constant regardless of the posture change of the boom 3 from the detection values from the means 8 and 9 and outputs the control signal to the drive control means 6. It is composed.
[0004]
The boom posture detection means 8 detects the posture change status of the boom 3 due to undulation or bending, and in this example, a lower boom 3a in which a base end portion as shown in FIG. The undulation angle θ1 from the horizontal level of the lower boom 3a because it is applied to an aerial work vehicle having a retractable boom 3 composed of an upper boom 3b attached to the front end of the lower boom 3a. And a bending / extension angle detecting means 8b for detecting a bending / extension angle θ2 of the upper boom 3b relative to the lower boom 3a.
[0005]
The swing angle detecting means 9 detects the swing angle θ3 of the work table 4 with respect to the tip of the boom 3 (the tip of the upper boom 3b). The angles θ1, θ2, and θ3 to be detected by these detection means are shown in FIG.
[0006]
The control signal output unit 10 uses the detection signals of the boom posture detection means 8 (the detection signals θ1 and θ2 of the undulation angle detection means 8a and the bending / extension angle detection means 8b) and the detection signal θ3 of the swing detection means 9. The control signal for maintaining the ground posture of the work table 4 constant regardless of the change in the posture of the boom 3 is calculated and output to the drive control means 6.
[0007]
In order to maintain the ground posture of the work table 4 regardless of the change in the posture of the boom 3,
θ1 + θ2 = −θ3
(However, θ1, θ2, and θ3 are positive in the counterclockwise direction in FIG. 2, and in the state of FIG. 2, θ1 has a sign of +, and θ2 and θ3 themselves have a sign of −.)
Therefore, the control signal output unit 10 obtains a control signal for maintaining this relationship and controls the drive control means 6 with this control signal.
[0008]
In the leveling device configured as described above, the boom posture detection means 8 and the swing angle detection means 9 immediately detect the posture change (undulation or bending) state of the boom 3 and the tilt angle of the work table 4) Since this is transmitted to the control signal output unit 10, there is a merit that leveling control can be performed immediately in response to a change in the posture of the boom 3, but there is a problem that the tilt of the work table 4 based on the bending of the boom 3 is not corrected.
[0009]
It should be noted that the boom posture detecting means 8 and the swing angle detecting means 9 are eliminated and replaced with an inclination angle detecting means that is attached to the work table 4 and detects the inclination of the work table 4 from the horizontal level. A leveling device configured to calculate and calculate a control signal for making the tilt angle from the tilt angle detecting means zero by the signal output unit 10 and to control the drive control means 6 of the swing actuator 5 with this control signal. Also exist. In this case, since the work table 4 is controlled so that the inclination from the horizontal level becomes zero, there is an effect that the inclination of the work table 4 due to the bending of the boom 3 is also automatically corrected. However, the tilt angle detecting means detects the tilt of the work table 4 from the horizontal level through the swing of the suspended pendulum, and the suspended pendulum is filled with a viscous fluid to suppress the unnecessary swing. Since it is usually mounted in the container, the detected value does not immediately respond to the inclination of the work table 4. For this reason, there is a problem that leveling control that responds immediately to the posture change of the boom 3 cannot be performed (responsiveness is poor).
[0010]
[Problems to be solved by the invention]
The present invention eliminates the problems of the conventional two-level leveling device, that is, can perform leveling control that responds immediately to the posture change of the boom 3, and automatically tilts the work table due to the bending of the boom 3. An object of the present invention is to provide a work table leveling device for an aerial work platform capable of correcting leveling to be corrected.
[0011]
[Means for solving problems]
The work table leveling device for an aerial work vehicle according to the present invention is configured as follows to achieve the above object. That is,
It is used in an aerial work vehicle having a work table 4 attached to the tip of the boom 3 that can freely change its posture by ups and downs or bends so that it can swing in the vertical direction. A leveling device that maintains a horizontal position, the swing actuator 5 swinging the work table 4 in the vertical direction, the drive control means 6 that controls the drive of the swing actuator 5, and the leveling that operates the drive control means 6. The leveling control means 7 comprises a boom attitude detection means 8 for detecting the attitude of the boom 3, a swing angle detection means 9 for detecting the swing of the work table 4 with respect to the tip of the boom 3, A control signal for maintaining the ground posture of the work table 4 constant regardless of the change in the posture of the boom 3 is calculated from the detection values from the detection means 8 and 9 and output to the drive control means 6. In those constituted by a control signal output unit 10,
An inclination angle detection means 11 for detecting an inclination angle from the horizontal level of the work table 4 is attached to the work table 4, and a detection value of the inclination angle detection means 11 is input to the control signal output unit 10 to output the control signal When calculating the control signal, the unit 10 corrects the detection value of the boom posture detection means 8 or the detection value of the swing angle detection means 9 with the detection value of the inclination angle detection means 11 to change the posture of the boom 3. Regardless of this, the platform leveling device for an aerial work vehicle is configured to calculate and output a control signal for maintaining the ground posture of the platform 4 in a horizontal state.
[0012]
The work table leveling device for an aerial work vehicle according to the present invention configured as described above has an inclination for detecting an inclination angle from the horizontal level of the work table 4 on the work table 4 in addition to the former two leveling device of the conventional two systems. An angle detection unit 11 is attached, and the detection value of the tilt angle detection unit 11 is input to the control signal output unit 10. The control signal output unit 10 includes a boom posture detection unit 8 and a swing angle detection unit 9. When calculating a control signal for maintaining the ground posture of the work table 4 constant regardless of the change in the posture of the boom 3 from the detected value, the detected value of the boom posture detecting means 8 or the detected value of the swing angle detecting means 9 is used. Since it is configured to calculate and output a control signal that is corrected by the detected value of the tilt angle detection means 11 and maintains the ground posture of the work table 4 in a horizontal state regardless of the change in the posture of the boom 3, It is leveling control that meet the arm 3 attitude change, it become possible to automatically correct possible leveling control the platform tilt by the boom 3 deflection.
That is, the leveling device combines the advantages of the conventional two-level leveling device.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a work table leveling apparatus for an aerial work vehicle according to the present invention will be described with reference to FIG.
Compared with the former leveling device of the above-mentioned two conventional leveling devices, the leveling device according to the present invention is provided with a tilt angle detecting means 11 for detecting a tilt angle from the horizontal level of the work table 4 in comparison with the former leveling device. And the difference in two points that the control signal calculation process in the control signal output unit 10 has been partially changed. The description of the former leveling device is incorporated.
[0014]
In FIG. 1, reference numeral 11 denotes a pendulum pendulum type tilt angle detecting means attached to the work table 4, which detects the tilt angle δθ from the horizontal level of the work table 4. The detected inclination angle δθ is input to the control signal output unit 10.
[0015]
The control signal output unit 10 uses the undulation angle detection unit 8a and the bending / extension angle detection unit 8b as the boom posture detection unit 8 and the detection signal θ3 of the swing angle detection unit 9 using the undulation angle θ1 and the bending / extension angle θ2. A control signal for maintaining the ground posture of the work table 4 constant regardless of the change in the posture of the boom 3 is calculated and output to the drive control means. The control signal is calculated and calculated. At this time, the control signal output unit 10 of the leveling device according to the present invention detects the detected value (the undulation angle θ1, the bending angle θ2) of the boom posture detecting means 8 or the detected value (θ3) of the swing angle detecting means 9 as an inclination angle. The control value is corrected by the detection value of the means 11 (inclination angle δθ), and a control signal for maintaining the ground posture of the work table 4 constant in a horizontal state irrespective of the posture change of the boom 3 is calculated and output.
[0016]
In particular,
θ1 + θ2 = −θ3−δθ
Alternatively, transfer δθ in this equation,
θ1 + θ2 + δθ = −θ3
(However, θ1, θ2, and θ3 are positive in the counterclockwise direction in FIG. 2, and in the state of FIG. 2, θ1 has a sign of +, θ2 and θ3 itself have a sign of −. Further, δθ is horizontal. The counterclockwise tilt from the level is +.)
The control signal necessary for maintaining the relationship is calculated and calculated. The work table 4 is leveled with the control signal calculated in this way (via the drive control means 6 and the swing actuator 5 driven thereby).
[0017]
By the way, maintaining the above relational expression means correcting the inclination of the work table 5 from the horizontal level in addition to maintaining the work table 4 at a constant ground position regardless of the change in the posture of the boom 3. Therefore, the work table 3 maintains the ground posture of the work table 4 in a horizontal state constant regardless of the change in the posture of the boom 3.
The control signal for maintaining the ground posture of the work table 4 constant regardless of the posture change of the boom 3 is the same as that of the former two-level leveling device of the conventional two types of boom posture detecting means 8 and swing angle detecting means 9. Since the detection is performed immediately in response to the detection result, leveling control can be performed in response to the boom 3 posture change. Further, the inclination angle δθ from the horizontal level of the work table 4 is automatically corrected. The correction of the work table 4 to the horizontal level is performed in response to a signal from the suspension pendulum type tilt angle detection means 11 having poor detection responsiveness. Since the correction of the inclination angle δθ from the horizontal level of 4 is not frequently performed, there is no particular problem.
[0018]
In FIG. 1, reference numeral 12 denotes a low-pass filter interposed in the input path to the control signal output unit 10 of the detection signal (inclination angle δθ) of the inclination angle detection means 11. Since the tilt angle detection means 11 is a suspended pendulum type attached to the work table 4, the suspended pendulum generated at the time of starting the posture change of the boom 3 swings unnecessarily and the detected value swings. The low-pass filter 12 is for filtering the fluctuation of the detected value. By attaching such a low-pass filter 12, stable leveling control can be performed.
[0019]
In the above embodiment, an example is shown in which the present invention is applied to an aerial work vehicle having a bend-extendable boom 3 constituted by a lower boom 3a and an upper boom 3b. Needless to say, it can also be applied to an aerial work vehicle with a boom of the type.
In this case, in the above embodiment, the boom posture detection means 8 is constituted only by the undulation angle detection means 8a, and the control signal output unit 10
θ1 = −θ3−δθ
Alternatively, transfer δθ in this equation,
θ1 + δθ = −θ3
A control signal for maintaining the above relationship may be calculated and calculated.
[0020]
In the above embodiment, the leveling device is always operated. However, the leveling control of the work table 4 is necessary only when the posture of the boom 3 is changed. You may make it operate a leveling apparatus only at the time of change operation.
[0021]
【effect】
The work table leveling device for an aerial work vehicle according to the present invention configured and operated as described above can perform leveling control in response to the change in the posture of the boom 3 and can be tilted by the bending of the boom 3 while having a simple configuration. It has the effect that it can correct | amend automatically.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a work table leveling device for an aerial work vehicle according to the present invention.
FIG. 2 is an explanatory diagram of an aerial work vehicle.
FIG. 3 is an explanatory diagram of a conventional platform leveling device for an aerial work platform.
[Explanation of symbols]
1; vehicle, 2; swivel, 3; boom, 3a; lower boom, 3b; upper boom,
4; work table, 5; swing actuator, 6; drive control means,
7; leveling control means; 8; boom posture detection means; 8a; undulation angle detection means;
8b; bending / extension angle detection means; 9; swing angle detection means; 10; control signal output unit;
11: inclination angle detecting means,
θ1: undulation angle, θ2: bending angle, θ3: swing angle, δθ: inclination angle,

Claims (1)

It is used for an aerial work vehicle having a work table 4 attached to the tip of the boom 3 that can freely change its posture by ups and downs or bends in a vertical direction. A leveling device that maintains a horizontal position, the swing actuator 5 swinging the work table 4 in the vertical direction, the drive control means 6 that controls the drive of the swing actuator 5, and the leveling that operates the drive control means 6. The leveling control means 7 comprises a boom attitude detection means 8 for detecting the attitude of the boom 3, a swing angle detection means 9 for detecting the swing of the work table 4 relative to the tip of the boom 3, and both of these. A control signal for maintaining the ground posture of the work table 4 constant regardless of the change in the posture of the boom 3 is calculated from the detection values from the detection means 8 and 9 and output to the drive control means 6. In those constituted by a control signal output unit 10,
An inclination angle detection means 11 for detecting an inclination angle from the horizontal level of the work table 4 is attached to the work table 4, and a detection value of the inclination angle detection means 11 is input to the control signal output unit 10 to output the control signal. When calculating the control signal, the unit 10 corrects the detection value of the boom posture detection means 8 or the detection value of the swing angle detection means 9 with the detection value of the tilt angle detection means 11 to change the posture of the boom 3. Regardless of this, the platform leveling device for an aerial work platform is configured to calculate and output a control signal for maintaining the ground posture of the platform 4 in a horizontal state.

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