JP2006111034A - Downgrade speed control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a downgrade speed control device enabling an operator to change easily the setting of the descending speed in accordance with the situation of the slope and the load and capable of enhancing the controllability in running on a downgrade. <P>SOLUTION: A downgrade brake control S2 of a controller 100 controls the brake amount so that the actual vehicle speed becomes identical to the target speed for descending on the downgrade by changing over the target speed in accordance with the position of a shift lever in a transmission sensed by a shift lever position sensor 21a. Also the controller 100 controls the brake amount by changing over the control factor for changing the braking force in accordance with the position of the shift lever. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a downhill speed control device that controls a downhill speed, and in particular, when a vehicle having a large load weight such as a dump truck is going downhill, the brake operation is appropriately performed to automatically reduce the downhill speed. The present invention relates to a downhill speed control device suitable for controlling the speed.

  Conventionally, in order to keep the vehicle speed on a downhill at a predetermined speed, an operator operates a foot brake or a lever to adjust a brake amount. However, in a place with a long hill such as a mine, it is complicated to operate the brake each time.

  Therefore, the target vehicle speed is set according to the road surface inclination angle detected by the road surface inclination sensor, and the retarder brake is controlled so that the vehicle speed detected by the vehicle speed sensor becomes the target vehicle speed. A downhill speed control device that saves labor is known (see, for example, Patent Document 1).

JP-A-6-135260

  However, the method described in Patent Document 1 requires a sensor for performing detection necessary for downhill braking control such as a slope state, a load, and a slope, and the price of the system becomes expensive. Moreover, generally used road surface inclination sensors often generate errors due to the influence of acceleration, and it is extremely difficult to accurately determine the inclination during traveling. In addition, the amount of braking required on a downhill varies depending on various factors. For example, it is necessary to adjust the amount of braking depending on factors such as whether the hill is earth or sand, paved, or wet. As a result, it becomes necessary to change the brake amount in response to changes in such factors. It is difficult to automatically set all such external factors, which is a problem in applying the control device.

  An object of the present invention is to provide a downhill speed control device that allows an operator to easily change the downhill speed setting according to the state of a slope or a load, and has improved controllability during downhill travel.

(1) In order to achieve the above object, the present invention provides a downhill speed control apparatus having a control means for controlling a brake amount so that an actual vehicle speed matches a target speed at the time of downhill. The brake speed is controlled by switching the target speed according to the position of the shift lever of the transmission.
With such a configuration, the setting of the downhill speed can be easily changed, and the controllability during downhill travel can be improved.

  (2) In the above (1), preferably, the control means further controls a brake amount by switching a control coefficient for changing a braking force in accordance with a position of the shift lever.

  (3) In the above (1), preferably, setting means for changing the target speed switched according to the position of the shift lever is provided.

  (4) In the above (2), preferably, setting means for changing the control coefficient switched according to the position of the shift lever is provided.

  (5) In the above (1), preferably, the control means invalidates the control of the brake amount when the position of the shift lever of the transmission is a specific position.

  According to the present invention, the setting of the downhill speed can be easily changed by the operator depending on the state of the hill or the load, and the controllability during traveling on the downhill can be improved.

Hereinafter, the configuration and operation of a downhill speed control apparatus according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the present invention is applied to a dump truck.
First, the configuration of a dump truck to which the downhill speed control device according to the present embodiment is applied will be described with reference to FIG.
FIG. 1 is a block diagram showing a configuration of a dump truck to which a downhill speed control device according to an embodiment of the present invention is applied.

  The driving force generated from the engine 10 is transmitted to the two driving wheels 30R and 30L via the transmission 20, the differential gear 30 and the axles 31R and 31L, and travels the body of the dump truck. Retarder brakes 40R and 40L that generate braking force for the drive wheels 30A and 30B are attached to the axles 31R and 31L. The retarder brakes 40R and 40L are supplied with hydraulic pressure from the pump P driven by the engine 10 via the brake valves 44R and 44L.

  The engine 10 is provided with an engine speed sensor 10a. The engine speed detected by the engine speed sensor 10 a is input to the controller 100. The transmission 20 is provided with a gear shift speed sensor 20a. The gear shift stage sensor 20a detects the currently used gear shift stage (4th speed, 3rd speed, 2nd speed, 1st speed, N (neutral), R (back)), and the detected gear speed stage signal is , Input to the controller 100.

  A brake force sensor 40a is provided between the brake valve 44L and the retarder brake 40L. The brake force sensor 40a detects the hydraulic pressure supplied to the retarder brake 40L and is input to the controller 100. The drive wheels 30R and 30L are provided with vehicle speed sensors 32R and 32L that detect the rotational speed of the wheels. Vehicle speed data detected by the vehicle speed sensors 32R and 32L is input to the controller 100. The setting device 200 is used for setting a target vehicle speed and a control coefficient. The target vehicle speed and control coefficient set by the setting device 200 are input to the controller 100.

  The shift lever 21 is provided with a shift lever position sensor 21a. The shift lever position sensor 21a detects the position of the shift lever (D (automatic), 4th speed, 3rd speed, 2nd speed, 1st speed, N (neutral), R (back)), and the detected shift lever position signal. Is input to the controller 100. The accelerator pedal 11 is provided with an accelerator pedal sensor 11a. The accelerator pedal sensor 11 a detects the amount of depression of the accelerator pedal 11 (or a state indicating whether or not the accelerator pedal 11 is depressed), and a detection signal is input to the controller 100.

  When the position of the shift lever detected by the shift lever position sensor 21a is the fourth speed, the third speed, the second speed, or the first speed, the controller 100 sets the target vehicle speed according to the position of each shift lever, and the vehicle speed A control signal is output to the electromagnetic proportional valves 42R and 42L so that the vehicle speed detected by the sensors 32R and 32L becomes the target vehicle speed. In addition, when the position of the shift lever detected by the shift lever position sensor 21a is 4th speed, 3rd speed, 2nd speed, or 1st speed, the controller 100 controls the braking force according to the position of each shift lever. And a control signal is output to the electromagnetic proportional valves 42R and 42L using the control coefficient. The control coefficient will be described later. Further, when the target vehicle speed is changed and set by the setting device 200, a control signal is output to the electromagnetic proportional valves 42R and 42L so as to be the target vehicle speed. The electromagnetic proportional valves 42R and 42L are connected to the brake valves 44R and 44L via the shuttle valves 43R and 43L, respectively, and control the brake valves 44R and 44L, respectively, so that the braking force generated in the retarder brakes 40R and 40L is generated. And control so that the vehicle speed becomes the target vehicle speed.

  The brake pedal 41 is connected to the shuttle valves 43R and 43L. The shuttle valves 43R and 43L are configured to select a higher pressure of the pressure from the brake pedal 41 and the pressure from the electromagnetic proportional valves 42R and 42L and transmit the selected pressure to the brake valves 44R and 44L. The retarder brakes 40R and 40L are normally automatically controlled by the controller 100. However, when the dump truck operator depresses the brake pedal 41, the retarder brakes 40R and 40L are operated to reflect the will of the operator, and the dumper The truck body can be stopped or decelerated. When the accelerator pedal 11 is depressed, the automatic brake control is released.

Next, the configuration of the controller 100 configuring the downhill speed control device according to the present embodiment will be described with reference to FIG.
FIG. 2 is a block diagram showing a configuration of the controller 100 that constitutes the downhill speed control device according to the embodiment of the present invention.

  The controller 100 includes an engine speed sensor 10a, vehicle body speed sensors 32R and 32L, a shift lever position sensor 21a, an accelerator operation amount sensor 11a for detecting an operation amount of an accelerator pedal, a brake force sensor 40a for measuring a braking force, and a gear shift. A gear shift stage sensor 20a for detecting a stage is connected to detect a state necessary for speed control.

  The controller 100 includes a CPU 110 that performs calculations, a timer 120 that drives the CPU, a clock 130 that acquires time, a ROM 140 that stores various processes (programs), a target speed and control variables for automatic control. A RAM 150 for recording a setting table, an input interface 160 for sensor input and communication, a user interface 170 for exchanging CPU calculation results and information necessary for speed setting with the setting device 200, and electromagnetic proportional valves 42R and 42L. And an output interface 180 for outputting a control signal for controlling the braking force.

  The CPU 110 executes various processes (programs) stored in the ROM 150. These processes are roughly divided into a gear shift process S1 for switching the gear shift stage according to the position of the shift lever and the engine load, a downhill brake automatic control S2 for controlling the brake amount so as to reach the target speed at the time of the downhill, There is a speed setting process S3 for setting a target speed during downhill. The contents of these processes will be described later with reference to FIG.

Next, the processing content of the gear shift processing S1 in the downhill speed control device according to the present embodiment will be described with reference to FIG.
FIG. 3 is an explanatory view showing the relationship between the gear shift stage used in the gear shift process S1 and the shift lever position in the downhill speed control apparatus according to the embodiment of the present invention.

  The operator operates the shift lever 21 and changes its position to change the gear speed. In general, in a mine dump truck, the position of the shift lever and the gear speed of the transmission do not correspond one-on-one, but also depending on the load applied to the engine 10 and the transmission 20 A system that automatically switches the gear speed is adopted.

  FIG. 3 shows a correspondence example between the position of the shift lever 21 and the gear speed of the transmission 20. In FIG. 3, when the lever position is back, neutral, and 1st gear, the gear shift stage is switched to correspond to back, neutral and 1st gear, respectively, but in the setting from 2nd gear to automatic (D range) The lever position only limits the upper limit of the gear shift stage. For example, when the third speed is selected as the shift lever position, the gear shift stage is automatically switched from the first speed to the third speed.

  In the gear shift process S1, the controller 100 takes in a signal from the shift lever position sensor 21a and determines the position of the shift lever 21. When the shift lever position is back, neutral, and first speed, the gear shift stage is switched to correspond to back, neutral, and first speed, respectively. When the shift lever position is from 2nd speed to automatic (D range), the controller 100 takes in a signal from the engine speed sensor 10a, and when the engine speed exceeds the upper limit speed value, the gear shift stage sensor. When shifting up from the current gear position detected by 20a and the engine speed falls below the lower limit rotation value, so as to shift down from the current gear position detected by the gear speed sensor 20a, The transmission 20 is controlled.

Next, the processing content of the downhill brake automatic control S2 in the downhill speed control apparatus according to the present embodiment will be described with reference to FIGS.
For mining dump trucks, transmission gear and downhill speed are recommended based on load capacity, downhill slope, downhill distance, and road resistance. This is a limitation due to the braking ability of the dump truck. Therefore, the operator performs the operation of switching the shift lever to a gear speed suitable for the slope when descending the slope.

Here, the relationship between the position of the shift lever and the corresponding speed range in the downhill speed control apparatus according to the present embodiment will be described with reference to FIG.
FIG. 4 is an explanatory diagram showing the relationship between the position of the shift lever used in the downhill braking automatic control S2 and the corresponding speed range in the downhill speed control apparatus according to the embodiment of the present invention.

  In the case of neutral (N), the vehicle body speed is 0 km / h. In the case of the back (R), the vehicle body speed range is, for example, −10 km / h to 0 km / h. In the case of the first speed, the vehicle body speed range is, for example, 0 km / h to 15 km / h. In the case of the second speed, the vehicle body speed range is, for example, 10 km / h to 30 km / h. In the case of the third speed, the vehicle body speed range is, for example, 15 km / h to 40 km / h. In the case of the fourth speed, the vehicle body speed range is, for example, 30 km / h to 50 km / h.

Next, the relationship between the position of the shift lever and the settable speed range in the downhill speed control apparatus according to the present embodiment will be described with reference to FIG.
FIG. 5 is an explanatory diagram showing the relationship between the position of the shift lever used in the downhill braking automatic control S2 and the settable speed range corresponding to the downhill speed control apparatus according to the embodiment of the present invention.

  In this embodiment, the target speed is set in accordance with the position of the shift lever, and the target speed for downhill control can be changed by a shift operation that is normally performed by the operator.

  The position of the shift lever, the preset target speed and the set value of the control coefficient are, for example, as shown in FIG. This setting value is stored in advance in a setting table in the RAM 150 shown in FIG.

  The set speed is set within a speed range corresponding to the position of the shift lever shown in FIG. For example, when the position of the shift lever is the first speed, the set speed is set to 8 km / h, and when the position of the shift lever is the second speed, the set speed is set to 15 km / h. For example, when the position of the shift lever is 3rd speed, the set speed is set to 18 km / h, and when the position of the shift lever is 4th speed, the set speed is set to 24 km / h.

  Furthermore, in this embodiment, the control coefficient is also set in advance corresponding to the position of the shift lever. The control coefficient is, for example, the strength of the braking force with respect to the error between the vehicle body speed Vr and the target speed Vtag. The controller 100 calculates a necessary braking force by PID calculation for the error between the vehicle body speed Vr and the target speed Vtag. Here, the control coefficient is a calculation coefficient of P calculation. Even when the error between the vehicle speed Vr and the target speed Vtag is the same, the greater the control coefficient, the greater the braking force. When descending when loading, it is preferable to descend at a low speed as much as possible and to increase the braking force at that time. Therefore, in this embodiment, for example, when the position of the shift lever is the first speed, the set speed is set to 8 km / h, and the control coefficient is set to a large value, for example, 3.4. By doing so, when the operator sets the shift lever position to the first speed, the target speed is reduced and the braking force is increased. On the other hand, when the position of the shift lever is the fourth speed, the set speed is set to 24 km / h, and the control coefficient is set to a small value, for example, 1.2.

Next, the processing contents of the downhill brake automatic control S2 in the downhill speed control apparatus according to the present embodiment will be described with reference to FIG.
FIG. 6 is a flowchart showing the processing contents of the downhill brake automatic control S2 in the downhill speed control apparatus according to the embodiment of the present invention.

  In step S210, the controller 100 detects a signal of the current shift lever position using a signal from the shift lever position sensor 21a.

  Next, in step S220, if the detected shift lever position is N (neutral), R (back), or D (automatic), the controller 100 ends the process, and the fourth speed, third speed, second speed, In the case of the first speed, the downhill braking process is executed in steps S230 and S240.

  That is, when the target position is not set as in the case where the position of the shift lever is automatic (D range), the control is suppressed so as not to perform the downhill control. By providing the position of the shift lever that does not perform such control, the downhill control does not work when the lever is in the automatic (D) state, so that control not intended by the operator does not occur. For example, when it is determined that the vehicle is descending on the basis of an inclination angle or the like, the brake is applied even at a timing when the operator does not want to decelerate when the tire enters the depression while traveling on flat ground. In some cases, such problems can be eliminated.

  On the other hand, in the downhill road, the operator shifts the shift lever from the 4th speed to the 1st speed in accordance with the inclination of the downhill road and the load amount, and tries to apply the engine brake. Then, the target speed can be automatically set according to such a shift operation of the operator, the brake is controlled so as to be the target speed, and the brake force also corresponds to the selected shift lever position. be able to.

  When the shift lever position is the fourth speed, the third speed, the second speed, or the first speed, the controller 100 reads the set speed and the control coefficient corresponding to the detected shift lever position from the setting table in step S230.

  Next, in step S240, the controller 100 performs a P calculation on the control coefficient read in step S230 with respect to the error between the vehicle speed Vr detected by the vehicle speed sensor 32R and the target speed Vtag read in step S230. As a coefficient, the brake force is calculated and output to the electromagnetic proportional valves 42R and 42L. The controller 100 performs feedback control so that the braking force detected by the braking force sensor 40a becomes the braking force output to the electromagnetic proportional valves 42R and 42L.

Next, the processing content of the speed setting process S3 in the downhill speed control apparatus according to the present embodiment will be described with reference to FIG.
FIG. 7 is an explanatory diagram for explaining the processing content of the speed setting processing S3 in the downhill speed control device according to the embodiment of the present invention.

  The speed setting process S3 is a process in which the operator sets a target speed and a control coefficient of the braking force for the setting device 200. The controller 100 reads the target speed and braking force control coefficients set by the setting device 200 and rewrites the target speed and braking force control coefficients set in advance in the setting table.

  As shown in FIG. 7, the setting device 200 includes a lever position display section 210A, a target speed display section 210B corresponding to the lever position, and a brake force display section 210C corresponding to the lever position. It has been. In the illustrated example, the position of the shift lever is “4th speed” (display unit 210A), the target speed at the lever position is “15 km / h” (display unit 210B), and the brake corresponding to the lever position is shown. An example in which the force is “medium” (display unit 210C) is illustrated. Here, the “medium” brake force is, for example, a case where the control coefficient for the shift lever position “4th speed” shown in FIG. 5 is “1.2”. Three types of control coefficients, “strong”, “medium”, and “weak”, are prepared in advance. For example, for the shift lever position “4th speed”, the control coefficient “strong” = 1.5, Switching is possible in three stages, such as “medium” = 1.2 and “weak” = 1.0.

  When switching the target speed (set speed), if the operator sets the speed up / down switch 220A to the UP side, the numerical value displayed on the target speed display section 210B increases, and if it is set to the DOWN side, the target speed display section. The numerical value displayed in 210B becomes smaller. When the speed setting volume 220B is rotated clockwise, the numerical value displayed on the target speed display unit 210B is increased, and when the speed setting volume 220B is rotated counterclockwise, the numerical value displayed on the target speed display unit 210B is decreased. In this way, when the operator changes the numerical value displayed on the target speed display unit 210B and presses the SET button 230, the changed set value is updated and set in the setting table. This is effective when the shift lever is set to that position.

  Also, when switching the braking force, when the operator sets the braking force up / down switch 220C to the UP side, the display of the braking force display unit 210C becomes “strong”, and when it is set to the DOWN side, the braking force display unit 210C. Is displayed as “weak”. In this way, when the operator changes the braking force displayed on the brake force display unit 210C and presses the SET button 230, the control coefficient corresponding to the changed braking force is updated and set in the setting table. Is done. This is effective when the shift lever is set to that position.

  Note that this speed setting and braking force setting may be performed before driving, or the actual vehicle speed is set as the target speed with the SET button while driving while actually setting the lever to the desired position. You may do it.

  There are not many patterns such as slope and distance in one mine or work site, and such a few patterns can be used practically by a method corresponding to a shift lever.

  As described above, the target speed and control coefficient can be switched in conjunction with the shift lever, so that the target downhill can be operated in a way that does not cause a sense of incongruity with the operation of the dump truck that normally operates the shift lever. Speed control is possible. Further, by providing a lever position that does not perform downhill speed control, it is possible to prevent the control from being performed without the operator's intention.

Although it is possible to drive the control with a switch or the like, it is not necessary to add such a special operation under conditions that require caution when traveling downhill, and whether or not the shift lever is operated The same effect can be obtained by normal track operation.

It is a block diagram which shows the structure of the dump truck to which the downhill speed control apparatus by one Embodiment of this invention is applied. It is a block diagram which shows the structure of the controller 100 which comprises the downhill speed control apparatus by one Embodiment of this invention. It is explanatory drawing which shows the relationship between the gear stage used in gear shift process S1 in the downhill speed control apparatus by one Embodiment of this invention, and a shift lever position. It is explanatory drawing which shows the relationship of the speed range corresponding to the position of the shift lever used in downhill brake automatic control S2 in the downhill speed control apparatus by one Embodiment of this invention. It is explanatory drawing which shows the relationship between the position of the shift lever used in downhill brake automatic control S2 in the downhill speed control apparatus by one Embodiment of this invention, and the settable speed range corresponding. It is a flowchart which shows the processing content of downhill brake automatic control S2 in the downhill speed control apparatus by one Embodiment of this invention. It is explanatory drawing explaining the processing content of the speed setting process S3 in the downhill speed control apparatus by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine 11 ... Accelerator pedal 20 ... Transmission 21 ... Shift lever 21a ... Shift lever position sensor 30 ... Differential gear 30R, 30L ... Drive wheel 31R, 31L ... Axle 32R, 32L ... Vehicle speed sensor 40R, 40L ... Retarder brake 40a ... Brake force sensor 41 ... Brake pedals 42R, 42L ... Brake solenoid valve 100 ... Controller 200 ... Setting device

Claims (5)

In the downhill speed control device having a control means for controlling the brake amount so that the actual vehicle speed matches the target speed at the time of downhill,
The downhill speed control device characterized in that the control means switches the target speed in accordance with the position of a shift lever of the transmission to control the brake amount. The downhill speed control device according to claim 1,
The downhill speed control device according to claim 1, wherein the control means further controls a brake amount by switching a control coefficient for changing a braking force in accordance with a position of the shift lever. The downhill speed control device according to claim 1,
A downhill speed control device comprising setting means for changing the target speed that is switched according to the position of the shift lever. The downhill speed control device according to claim 2,
A descending slope speed control device comprising setting means for changing the control coefficient switched according to the position of the shift lever. The downhill speed control device according to claim 1,
The downhill speed control device characterized in that the control means disables the control of the brake amount when the position of the shift lever of the transmission is a specific position.

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