JP2511936B2 - Blade tilt control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is applied to a ground leveling machine such as a bulldozer (tilt dozer), and a blade for automatically setting and controlling the tilt angle of the blade at the time of soil transportation work. The present invention relates to a tilt control device.

[Conventional technology]

When excavation and soil work is performed using such a bulldozer, the load on the bulldozer is rarely uniform on the left and right. Often occurs.

However, if this is a tilt dozer in which an actuator (usually a hydraulic cylinder) for tilting work is provided for the blade and tilting is possible even in the driver's seat, this can be done by appropriate tilting of the blade. It is possible to balance the load applied to each time, and it is also possible to prevent rising running bends.

Incidentally, such tilting operation of the tilt dozer is performed via a steering lever called a tilt lever provided in the driver's seat, and the hydraulic cylinder (depending on the operation direction and operation amount of the tilt lever by the operator). The drive direction and the drive amount of the expansion and contraction of the tilt cylinder) are hydraulically controlled. In addition, the above-mentioned blade is usually connected at one upper end to this tilt cylinder and at the other upper end to a universal joint called a brace (the other end of each of the cylinder and the brace is connected to a blade frame. If the cylinder is extended, the side connected to the cylinder is tilted so as to lift, and if the cylinder is retracted, the side connected to the brace is tilted so as to be lifted.

Therefore, when the load on the blade is large on the left side and the bulldozer tends to bend to the left side, the left side of the blade is lifted to the right side based on the action of the tilt cylinder. By tilting (hereinafter, the tilting operation of this mode is referred to as right tilt), this load can be reduced, and this bending to the left can be prevented and corrected, and conversely, the load on the right side is large and the vehicle can run to the right. If there is a tendency to bend, by lifting the right side of the blade and tilting it to the left side (this tilting operation is also called left tilt), it is possible to prevent and correct this running bend to the right side. . In normal earthmoving work, such an operation related to tilting (tilt lever operation) is repeated about once every four seconds.

[Problems to be solved by the invention]

In the ground leveling machine such as the tilt dozer, although it is possible to correct the traveling trajectory by executing such tilting, the operation itself related to the tilting itself is entirely entrusted to the operator's control. Moreover, since it requires a considerable amount of skill, it imposes a considerable burden on the operator.
Further, even a skilled operator has a large amount of fatigue because of frequent operation as described above.

The present invention intends to automate the above-mentioned tilting operation in a preferable manner so as not to bother the operator in this way.

[Means for solving problems]

According to the present invention, an accelerometer for measuring the yawing acceleration of the soil leveling machine during the above-mentioned soil transportation, and the measured yawing acceleration are integrated at a predetermined interval for each of the same intervals with respect to a certain reference traveling direction of the leveling machine. Calculation means for calculating the bending amount, and control means for controlling the driving mode of the blade tilt angle varying actuator such as the tilt cylinder so that the integrated value of the calculated bending amount approaches zero each time this calculation is executed. At least, the operation related to the tilting is automated.

[Action]

By adopting the yawing accelerometer, the bending amount of the machine can be easily calculated, and in particular, the predetermined interval for this calculation is the shortest possible inching even when the operator operates the tilt lever. By setting the time, it is possible to achieve bending correction with high accuracy as high as that of a skilled operator without bothering the operator.

In the control means, the tilt direction of the blade that can bring the integrated value close to zero based on the sign of the integrated value of the calculated bending amount, and this value is also set to zero based on the absolute value of the integrated value. The tilt amount of the blade that can be brought closer to is determined, and the drive of the actuator is controlled so that the determined tilt direction and tilt amount are satisfied.

〔Example〕

First, the principle of the present invention will be described with reference to FIGS.

Here, the tilt dozer described above is assumed as a soil leveling machine, and a control principle in the case where the present invention is applied to blade tilt control during soil transportation work of the tilt dozer will be described.

FIG. 3 shows the appearance of the tilt dozer,
In FIG. 3, BD is a blade, FM is a frame that supports the blade BD, RS is a lift cylinder for moving the blade BD up and down, and BS is between one upper end of the blade BD and one of the frames FM. The above-mentioned brace connected as shown, 50 is a tilt cylinder connected between the other upper end of the blade BD and the other of the frame FM as shown to tilt the blade BD as required, and 11 is this tilt Tilt lever 11 operated by the operator when tilting the blade BD via the cylinder 50
Are shown respectively.

Incidentally, as shown in FIG. 4, in the relationship between the blade BD and the tilt cylinder 50 and the brace BS, when the tilt cylinder 50 is extended as shown by the arrow in the figure, it is connected to the tilt cylinder 50 of the blade BD. The tilted side is tilted so that it is lifted as shown by the arrow in the figure (right tilt in the illustrated example), and conversely, when the tilt cylinder 50 is retracted, the side of the blade BD that is connected to the brace BS is tilted (raised). As described above, in the case of (1), it is tilted to the left).

Further, when carrying out soil carrying work of such a tilt dozer, when the magnitude of the load applied to the blade BD is biased to the left side, for example, and there is a tendency for traveling bending to the left side, the blade BD is tilted to the right by the above action of the tilt cylinder 50. This running bend can be corrected, and conversely, when the load applied to the blade BD is biased to the right side and the running bend tends to occur on the right side, the tilt cylinder 50 acts to cause the blade to move. As described above, it is possible to correct this traveling bend by tilting the BD to the left.

Now, in automating such a tilt operation of the blade BD, in the present invention, this is realized by the following method, for example.

FIG. 5 and FIG. 6 are schematic views showing the traveling modes of the tilt dozer, which is supposed to be carrying out earthmoving work, at a certain point in time as seen from the plane and the rear front, respectively. In FIG. 6, 13a and 13b are arranged symmetrically with respect to, for example, the center of gravity of the tilt dozer in the lateral direction, that is, in the left-right direction, and yaw acceleration that measures the lateral bending or yawing acceleration when the tilt dozer travels. The reference numeral 14 designates an accelerometer (acceleration sensor), and 14 designates an inclinometer which is arranged at, for example, the center of gravity of the tilt dozer and measures the degree of inclination in the left-right direction.

That is, in this example, the yawing accelerometers 13a and 13b and the inclinometer 14 are used to automatically detect the traveling bend of the tilt dozer in the left-right direction.

For example, if the tilt dozer is leftwardly bent as shown in FIG. 5 during a certain time Δt on a slope that is inclined to the right and has an inclination angle θ as shown in FIG. The acceleration α due to bending is represented by α = −Gsinθ (1). Where is the yaw accelerometer
The acceleration is measured by 13a and 13b, and θ is the tilt value measured by the inclinometer 14.

In this way, if the acceleration α due to the traveling bending is obtained, the left and right (in this case, left) variable position x due to the acceleration α is double integrated to obtain x = ∫∫αdtdt = ∫∫ (−Gsinθ) dtdt (2), and the integrated value of this variable position x after a certain time (Δt × i) is X. Can be obtained as

Therefore, in this case, if the value of the variable position (bending amount) integrated value X thus obtained is a positive value (at least in the examples shown in FIGS. 5 and 6), the blade
A drive command for instructing expansion is appropriately given to the tilt cylinder 50 to set BD to the right tilt, and conversely, if the integrated value X is a negative value, the blade BD is set to the left tilt. By appropriately giving a drive command to the tilt cylinder 50 to instruct degeneration, it is possible to bring the value of the displacement amount integrated value X close to zero, that is, to correct the desired trajectory. Become.

It should be noted that the method of giving the tilt amount at the time of the right tilt or the left tilt is arbitrary, and for example, when the traveling surface is close to a horizontal plane, and the trajectory can be corrected with a small and constant tilt amount. For this reason, it is sufficient to continue to give such a certain tilt amount while constantly monitoring the displacement amount integrated value X, and if such a constant tilt amount is continuously given, it is difficult to correct the desired trajectory. In such a case, the tilt amount may be variably set according to the magnitude of the displacement amount integrated value X.

1 and 2 show an embodiment of the blade tilt control device according to the present invention, which is constructed based on such a principle. Also in this embodiment, the tilt dozer shown in FIG. 3 is assumed as the ground leveling machine.

In the apparatus of this embodiment shown in FIG. 1, 11 is a tilt lever used for tilting the above-mentioned blade BD, and here, in particular, it is normally neutral (neutral).
Each time the controller 30 is operated at an appropriate position, an electric signal (hereinafter, referred to as a stroke signal) corresponding to the operation direction (two directions, front and rear or left and right) and the operation amount, is generated by the controller 30. It is assumed that it is an electric lever that outputs to. This structure and the like are already known.

In the apparatus of the same embodiment, 12 is the tilt lever
It is placed in an appropriate part in the cockpit as in 11, and turned on depending on whether or not to automate the tilt control operation of the blade,
This is a mode selection switch that is turned off. Particularly in this example, as shown in FIG. 1, the switch element 12a is turned on,
A signal having a logical value “0” and a signal having a logical value “1” are output according to the off state, and the controller 30 is informed of the selection mode according to the contents of the logical value. ing. Here, the switching element 12
When "a" is "on" (logical value "0") "Automatic mode" is selected and when "off" (logical value "1")
Suppose that "manual mode" is selected.

Incidentally, the "automatic mode" is a mode in which the controller 30 is instructed to automatically perform the operation related to the tilt control of the blade BD based on the above principle, and the "manual mode" is the blade mode. This is a mode in which the controller 30 is instructed to execute all the operations related to the tilt control of the BD according to the operation mode of the tilt lever 11 by the operator, that is, according to the stroke signal. However, in this embodiment, as will be described later in detail, even when the "automatic mode" is designated, the stroke signal is prioritized when the tilt lever 11 is operated. It has become.

Further, the yawing accelerometer 13 (13a, 13b) and the inclinometer 14 are respectively shown in FIGS. 5 and 6 to measure the above-described acceleration and inclination θ (see FIGS. 6 and (1)). It is a sensor that is arranged and mounted on the tilt dozer in the mode shown. These sensor outputs are also captured by the controller 30. As the yawing accelerometer 13 (13a, 13b), various acceleration sensors such as a piezoelectric type, a strain gauge type, an electrodynamic type, a servo type, etc. can be used in addition to a particle gyro.

The timing setter 21 determines the interval time when the controller 30 executes the calculation of the above formulas (1) to (3) based on the sensor outputs of the yaw accelerometer 13 (13a, 13b) and the inclinometer 14, that is, This is a setter for setting the time Δt shown in FIG. 5 above. By the way, according to the actual work analysis on the tilt lever operation by a skilled operator, the minimum inching time is about 0.1
Since this is the second, this minimum inching time is also adopted in this embodiment, and Δt = 0.
An interval time of 1 second shall be preset. That is, it is assumed that the timing setter 21 outputs a timing signal for instructing the operation execution timing of the controller 30 at 0.1 second intervals.

Further, the allowable value setting device 22 is set such that a limit value (which is referred to as X ₀ ) of the amount of bending from the target (desired) running track, which is allowed when the tilt dozer is traveling for soil transportation work, is preset. It is a vessel. That is, in this embodiment,
When the bending amount integrated value of the tilt dozer (refer to the equation (3)) calculated by the controller 30 is less than or equal to the set allowable limit value X ₀ , the blade tilt control related to the trajectory correction is performed. I try not to.

Further, 41 is a hydraulic pump driven by the engine EN, 42 is the flow rate of pressure oil supplied from the pump 41 to the tilt cylinder 50, which is a hydraulic cylinder, based on flow rate command signals S1 and S2 output from the controller 30. It is a pressure oil flow rate control valve for controlling.

Incidentally, the pressure oil flow rate control valve 42 executes the pressure oil flow rate control of the tilt cylinder 50 in the following manner.

Poppet valves PV1 to PV4 correspond to the flow control valves, and solenoid valves EV1 and EV are used as the flow control valves.
2 is equivalent. And solenoid valve EV1 is poppet valve PV1, PV2
The solenoid valve EV2 controls the poppet valves PV3 and PV4 to control the amount of pressure oil in the direction of retracting the tilt cylinder 50.

Now, a case where the command flow rate is supplied in the direction in which the tilt cylinder 50 is extended will be described.

In this case, the flow rate command signal S1 is applied to the solenoid of the solenoid valve EV1 from the controller 30 via the signal line l1. The solenoid valve EV1 moves its spool position according to the flow rate command signal S1 applied to the solenoid.

As a result, pressure oil according to the throttle OF and the spool position of the solenoid valve EV1 is added to the poppet valve PV1, and this poppet valve PV1 provides the flow rate according to the oil pressure, that is, the command flow rate via the check valve CV1 and the oil passage r1. Tilt cylinder 50 and oil supply / drain port a.

On the other hand, as the pressure oil is supplied to the oil supply / discharge port a of the tilt cylinder 50, the pressure of the oil passage r2 connected to the oil supply / discharge port b side of the cylinder 50 rises. Since the oil passage r3 is connected to the oil passage rD via the valve EV1, the pressure in the oil passage r3 decreases, and as a result, the poppet valve PV2 opens, and the pressure oil on the oil supply / exhaust port b side of the tilt cylinder 50 becomes oil. Path r2, poppet valve PV2,
And to the drain D through the oil passage rD.

As described above, the poppet valve PV is set by the solenoid valve EV1.
1, PV2 is controlled, and the flow rate according to the flow rate command signal S1 applied to the solenoid of the solenoid valve EV1 is applied in the direction of extending the tilt cylinder 50. Incidentally, when the required flow rate is made to flow in the direction of retracting the tilt cylinder 50, it is performed by controlling the poppet valves PV3, PV4 by the solenoid valve EV2 to which the flow rate command signal S2 is applied via the signal line l2. Since these valves are provided symmetrically with the solenoid valve EV1 and the poppet valves PV1 and PV2 and perform the same operations, detailed description thereof will be omitted.

In the controller 30, when the “manual mode” is selected through the mode selection switch 12, the flow rate command signal S1 or S2 is formed and output based on the stroke information applied from the tilt lever 11, and the “manual mode” is selected through the switch 12. When the "automatic mode" is selected, the variable position x obtained by the above equations (2) and (3) from the measured values of the yaw accelerometer 13 (13a, 13b) and the inclinometer 14 and θ. Also, based on the integrated value X, the same flow rate command signal S1 or S2 is formed and output.

FIG. 2 is a flowchart showing an operation example of the controller 30 when the “automatic mode” is selected. Hereinafter, referring to FIG. 2, the blade tilt automatic control of the apparatus of this embodiment will be described. The operation mode will be described in detail.

In this example device, even in "automatic mode",
The tilt control based on the operation of the tilt lever 11 is given the highest priority. Therefore, also in the blade tilt automatic control described here, this tilt lever 11 is in the neutral position (usually, there is a dead zone near this, and the neutral position here includes this dead zone). Is executed on condition. less than,
The procedure is listed below.

1) The controller 30, which has determined that the tilt lever 11 is in the neutral position as described above, then moves to the timing setter.
Each of the yaw accelerometers 13 (13a, 13b) and the inclinometer 14 receives the respective measured value and θ on the condition that the timing signal is emitted from 21 (acceleration value is 0.1 second which is the interval time of the timing signal). Suppose you get this as the average acceleration of.

2) The controller 30 obtains the travel bending amount x of the tilt dozer for the interval time by executing the calculation of the equation (2) using the received measured value and θ.

3) In the controller 30, the calculated bending amount x
Is added to the integrated value up to that point regarding the same bending amount. That is, the calculation of the above equation (3) is executed.

4) After that, the controller 30 compares the integrated value X of the bending amount with the allowable limit value x ₀ preset in the allowable value setting device 22, and if X ≦ x ₀ , that is, the traveling bending occurs. If this is not the case, or if this is acceptable, then the current flow rate command signal S1 or S2 should be maintained in order to maintain the current tilt angle of the blade BD.
Is fixed, and if X> X ₀ , that is, if there is more than one allowable traveling bend in the left or right direction, the sign of the integrated value X indicates when the value is, for example, “negative”. When the flow rate command signal S2 is increased according to the value of the integrated value X, conversely, when it is "positive", the flow rate command signal S1 is increased according to the value of the integrated value X.

Perform processing. (The extent to which these increases can be determined empirically). Incidentally, in the pressure oil flow rate control valve 42, when the flow rate command signal S2 is increased in response to such processing of the controller 30, the tilt cylinder 50 is retracted according to the magnitude of the command signal S2. That is, the blade BD is tilted to the left according to the magnitude of the command signal S2.

When the flow rate command signal S1 is increased by performing the control, the tilt cylinder 50 is extended according to the magnitude of the command signal S1. That is, the blade BD is tilted to the right according to the magnitude of the command signal S1.

Take control.

By repeating the processes 1) to 4) each time the timing signal is generated, that is, every 0.1 seconds in this example, the traveling path of the tilt dozer is automatically corrected with the accuracy of a trained operator. As a result, the above condition X ≦ x ₀ is immediately satisfied.

Also, at any point in time, the tilt lever 11
Is operated beyond the dead zone, the controller 30 detects that based on the level of the stroke signal, and the stroke signal has a code or value corresponding to the tilt of the blade BD to the left. If the stroke signal is output, increase the flow rate command signal S2 according to the value of the stroke signal.

When the stroke signal is output with a code or value corresponding to the tilt of the blade BD to the right, the flow rate command signal S1 is increased according to the value of the stroke signal.

Perform processing. Then, in the controller 30, when the stroke signal is canceled, that is, the tilt lever 11
When the tilt dozer is returned to the neutral position, the process for the blade tilt automatic control of 1) to 4) described above is restarted by using the traveling direction of the tilt dozer at this time as the target traveling trajectory.

The processing mode based on the operation of the tilt lever 11 of the controller 30 is the same when the "manual mode" is selected. Then, in this case, when the "automatic mode" is selected through the mode selection switch 12, the process of 1) to 4) is started with the traveling direction of the tilt dozer at this time as the target traveling path.

By the way, in the device of this embodiment, the magnitude of the flow rate command signal S1 or S2, that is, the tilt amount is changed according to the integrated value X of the bending amount, but as described in the above principle,
How to give such a tilt is arbitrary. The point is that the driving mode of the tilt cylinder is controlled so that the integrated value X approaches zero every time the calculation is executed based on the timing signal. All you have to do is

That is, when the trajectory can be sufficiently corrected with a certain tilt amount, the integrated value X is continuously monitored and the constant tilt amount is continuously applied, or It is also possible to control the drive of the tilt cylinder so that the blade is tilted step by step at a small predetermined angle. By the way, in the latter case, by the tilt control in the first stage. If the integrated value X of the calculated bending amount approaches zero, the tilt cylinder of the first stage is maintained until the integrated value X falls within a predetermined value corresponding to the allowable limit value x _0. If it is difficult to keep the drive position and the integrated value X of the same amount of bending is still close to zero even by the tilt control of the first step, the tilt angle is further increased by a predetermined angle. The tilt control is executed and the value of the integrated value X is similarly monitored. By performing such tilt control, the running of the soil leveling machine and the correction of its running bend can be performed very smoothly.

Further, in the apparatus of the above-mentioned embodiment, the inclinometer 14 is provided, and measurement is performed through the yawing accelerometer 13 (13a, 13b).
The calculated bending amount is corrected by the traveling surface inclination angle at each time (see the above equations (1) and (2)), so that a very accurate value can be obtained as the same bending amount. , For example, when carrying out earthmoving work in a workplace where the traveling surface is close to a horizontal plane, or when such accuracy is not required to correct the traveling trajectory, the inclinometer 14 may be deleted. You can also do it.

Further, in the apparatus of the embodiment, the yawing accelerometer 13
Although two left and right accelerometers 13a and 13b are used as the above, the number or arrangement method is not limited to the embodiment shown in FIG. 5 or FIG. If there is at least one yawing accelerometer, it is possible to detect the bending amount according to the above-mentioned principle.

It should be noted that, as the controller 30 which executes the calculation for detecting such a bending amount and the format output of the flow rate command signals S1 and S2 based on the calculated value, the controller having the built-in computer is assumed in the above-mentioned embodiment. It is of course arbitrary, and it is of course possible to configure this by a hardware circuit including first and second arithmetic circuits that execute at least arithmetic operations corresponding to the expressions (2) and (3).

The pressure oil flow rate control valve 42 that receives the flow rate command signals S1 and S2 and controls the drive mode of the tilt cylinder 50 also has any other form as long as it has a configuration that can achieve the same function as the above. It may be a control valve.

Further, it is needless to say that the present invention can be applied without being limited to the above-mentioned tilt dozer as long as it is a ground leveling machine having a blade and an actuator for variably setting the tilt angle.

[Effects of the Invention] As described above, according to the present invention, the operation related to blade tilting during soil transportation work is favorably automated, and any operator can easily and easily reach the level of an expert. The soil leveling machine can be operated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a blade tilt control device according to the present invention, FIG. 2 is a flow chart showing an operation example of the device of the same embodiment, and FIG. 3 is an external view of a tilt dozer to which the present invention is applied. FIG. 4 is a perspective view showing a blade tilting mode by a tilt cylinder,
FIG. 5 and FIG. 6 are schematic diagrams showing examples of traveling modes of the tilt dozer used for explaining the principle of the present invention. 11 …… Tilt lever, 12 …… Mode selection switch, 13
(13a, 13b) …… Yaw accelerometer, 14 …… Inclinometer, 2
1 …… Timing setter, 22 …… Allowable value setter, 30 ……
Controller, 42 ... Pressure oil flow control valve, 50 ... Tilt cylinder, BD ... Blade, BS ... Brace.

Claims (1)

(57) [Claims] 1. A ground leveling machine having a blade and an actuator for variably setting a tilt angle of the blade,
An accelerometer that measures the yawing acceleration when the soil leveling machine is working, and the measured yawing acceleration are integrated at a predetermined interval to calculate the amount of bending at the same interval with respect to a certain reference traveling direction of the soil leveling machine. A blade tilt control device comprising: a calculation means for performing the calculation, and a control means for controlling the driving mode of the actuator so that the integrated value of the calculated bending amount approaches zero each time the calculation is executed.