JPH08133043A - Automatic traveling vehicle - Google Patents

Abstract

PURPOSE: To prevent fluctuation in a vehicle speed in a drastic change of a traveling load of a vehicle so as to accomplish smooth traveling. CONSTITUTION: In the case of a high traveling load, if a vehicle speed detection value is larger than a target vehicle speed by an offset value or more (step Sb6), a command value for required braking force is rapidly increased by a value d2 (step Sb7), and on the other hand, in the case of a low traveling load, if a vehicle speed detection value is smaller than the target vehicle speed by the offset value or more (step Sb2), the command value for required braking force is rapidly reduced by a value d1 (step Sb3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic vehicle capable of preventing a change in vehicle speed caused by a sudden change in running load of the vehicle.

[0002]

2. Description of the Related Art Conventionally, various types of automated vehicles used as golf carts for carrying luggage such as golf bags and people in golf courses have been developed. As this type of automatic vehicle, for example, the one disclosed in Japanese Patent Laid-Open No. 6-24257 is known. In the automatic vehicle disclosed in this publication, when the traveling load of the vehicle (the resistance that tries to hinder the traveling of the vehicle) suddenly decreases, such as when descending a slope, the vehicle overshoots due to the sudden decrease of the load (vehicle speed increases rapidly). The throttle opening is controlled so as to prevent the electric pop-up) and an electric braking force is applied.

[0003]

However, in the automatic vehicle disclosed in the above publication, the above-mentioned control is performed after the sudden decrease of the traveling load is detected, so that the braking is applied against the change of the vehicle speed. Slows down. Therefore, there is a problem that the vehicle speed fluctuates due to the braking after the vehicle speed rapidly increases due to the sudden decrease of the traveling load, and the vehicle becomes unstable.

The present invention has been made under such a background, and provides an automatic vehicle capable of preventing a change in vehicle speed which occurs when a traveling load of the vehicle suddenly changes and performing smooth traveling. Is intended.

[0005]

According to a first aspect of the present invention, there is provided an automatic vehicle in which a vehicle speed detection value and a target vehicle speed are compared with each other and the necessary braking force to be applied to the vehicle is controlled so that they coincide with each other. A load detecting means for detecting a traveling load of the vehicle, and, when the traveling load is a high load, and when the vehicle speed detection value is larger than the target vehicle speed by a predetermined value or more, the command value of the required braking force is a predetermined value. Braking command value control means for rapidly decreasing the command value of the required braking force by a predetermined value when the vehicle speed detection value is smaller than the target vehicle speed by a predetermined value or more when the traveling load is low. It is characterized by having.

According to a second aspect of the present invention, in the first aspect of the invention, after the braking command value control means suddenly increases or decreases the command value of the required braking force, the high or low state of the running load is changed. It is characterized by comprising a returning means for returning the command value of the required braking force to a normal control command value corresponding to the result of comparison between the vehicle speed detection value and the target vehicle speed when changed.

According to a third aspect of the present invention, a load detection for detecting a running load of a vehicle is performed in an automatic vehicle that compares the detected vehicle speed with a target vehicle speed and controls the throttle opening so that they match. And the traveling load is a high load, and when the vehicle speed detection value becomes larger than the target vehicle speed by a predetermined value or more, the command value of the throttle opening is sharply reduced by a predetermined value to reduce the traveling load. When the vehicle speed detection value becomes smaller than the target vehicle speed by a predetermined value or more, the opening command value control means for rapidly increasing the throttle opening command value by a predetermined value is provided.

According to a fourth aspect of the present invention, in the third aspect of the invention, after the opening command value control means sharply decreases or increases the command value of the throttle opening, the traveling load is in a high or low state. Is changed, or when the vehicle speed detection value falls within a predetermined value from the target vehicle speed, the throttle opening command value is set to a normal control corresponding to the comparison result of the vehicle speed detection value and the target vehicle speed. It is characterized in that it is provided with a returning means for returning to the command value.

According to a fifth aspect of the present invention, the detected vehicle speed is compared with the target vehicle speed, and in an automatic vehicle that travels while controlling the necessary braking force to be applied to the vehicle so that they match, the running load of the vehicle is reduced. When the vehicle speed detection value is higher than the target vehicle speed by a predetermined value or more in a case where the traveling load is a high load, the command value of the required braking force is rapidly increased by a predetermined value, and the traveling is performed. When the vehicle speed detection value is smaller than the target vehicle speed by a predetermined value or more when the load is low, a braking command value control unit that rapidly reduces the command value of the required braking force by a predetermined value, and the traveling load is high. In the case of a load, when the vehicle speed detection value becomes larger than the target vehicle speed by a predetermined value or more, the throttle opening command value is sharply reduced by a predetermined value, and when the traveling load is a low load, the vehicle speed detection is performed. There when smaller than a predetermined value than the target vehicle speed, is characterized by comprising the opening command value control means for the command value of the throttle opening is rapidly predetermined value min.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, after the braking command value control means sharply increases or decreases the command value of the required braking force, the high or low state of the running load is changed. When there is a change, the first braking means resets the command value of the required braking force to a normal control command value corresponding to the comparison result of the vehicle speed detection value and the target vehicle speed, and the opening command value control means controls the throttle opening. Of the throttle opening, when the high or low state of the traveling load changes, or when the vehicle speed detection value comes to fall within a predetermined value from the target vehicle speed after the command value is suddenly decreased or rapidly increased. It is characterized by further comprising a second returning means for returning the command value to a normal control command value corresponding to the comparison result of the vehicle speed detection value and the target vehicle speed.

[0011]

According to the first aspect of the invention, the load detection means detects the traveling load of the vehicle, and the braking command value control means determines that the vehicle speed detection value is higher than the target vehicle speed when the traveling load is high. The command value of the required braking force is suddenly increased by a predetermined value when it becomes larger than a predetermined value, and the command value of the required braking force is set when the detected vehicle speed becomes smaller than the target vehicle speed by a predetermined value or more when the traveling load is low. Is sharply reduced by a predetermined value. As a result, the braking force is adjusted without delaying the fluctuation of the vehicle speed when the traveling load changes suddenly, and the fluctuation of the vehicle speed can be prevented.

According to the second aspect of the present invention, after the vehicle speed is prevented from fluctuating due to a sudden change in the traveling load, the braking control is returned to the normal braking force command value.

According to the third aspect of the present invention, the load detection means detects the traveling load of the vehicle, and the opening degree command value control means determines that the detected vehicle speed is the target vehicle speed when the traveling load is high. When the vehicle speed detection value is smaller than the target vehicle speed by a predetermined value or more when the traveling load is low, the throttle opening command value is decreased by a predetermined value. Rapidly increase the value by the specified value. As a result, the throttle opening is adjusted without delaying the fluctuation of the vehicle speed when the traveling load suddenly changes, and the fluctuation of the vehicle speed can be prevented.

According to the fourth aspect of the present invention, after the fluctuation of the vehicle speed due to the sudden change of the traveling load is prevented, the opening control is returned to the normal opening command value.

According to the fifth aspect of the present invention, the braking force and the throttle opening are adjusted without delaying the fluctuation of the vehicle speed when the traveling load suddenly changes, and the fluctuation of the vehicle speed can be prevented more effectively.

According to the sixth aspect of the present invention, the vehicle speed is prevented from fluctuating due to a sudden change in the running load, and then the normal braking force command value and the opening command value are returned to the braking control and the opening control. At this time, the braking control, which has a relatively quick response, is difficult to return, and the throttle opening control, which has a relatively slow response, is easy to return, so the return timing is adjusted appropriately.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (1) Configuration of Embodiments Configuration of Automated Driving Vehicle FIG. 1 is a block diagram showing the configuration of an automated traveling vehicle according to an embodiment of the present invention. The automatic vehicle shown in this figure is used as, for example, a golf cart used in a golf course, and is equipped with an engine 1 as in a normal automobile, and the engine 1 is provided with a V-belt type automatic transmission 1a. A transmission 3 for transmitting the supplied driving force to the rear wheels 2a, 2b which are driving wheels, a steering wheel 4 for steering the front wheels 2c, 2d, and an accelerator pedal 5 for adjusting the throttle opening to change the vehicle speed. And governor 6,
It has a brake pedal 7 for braking the vehicle and a mechanical brake mechanism such as drum brakes 8a to 8d.

Further, the automatic traveling vehicle is capable of not only ordinary manual operation traveling (hereinafter referred to as manual traveling) but also automatic traveling. A controller 9 for controlling this automatic traveling, a steering driver 10, A steering motor 11, a throttle motor 12, a brake motor driver 13, a brake motor 14, an electromagnetic brake 15, a sensor group such as a guide line sensor 16 and a fixed point sensor 17, a steering clutch 18 for switching between manual traveling and automatic traveling, and a throttle. It has various switching mechanisms 20, 21 such as the clutch 19.

The steering driver 10 supplies a drive current corresponding to a steering instruction signal output from the controller 9 to the steering motor 11 during automatic traveling to rotate the steering shaft 22. At this time,
The steering wheel 4 is disengaged from the steering shaft 22 by the steering clutch 18, and manual operation is disabled.

The throttle motor 12 is driven in response to an opening instruction signal output from the controller 9 during automatic traveling, and the throttle clutch 19 is similarly engaged in response to an ON instruction signal output from the controller 9. It At this time, the switching device 21 switches the drive system of the engine 1 from the governor 6 side to the throttle motor 12 side. As a result, during automatic traveling, the throttle opening is adjusted according to the drive amount of the throttle motor 12 instead of the operation amount of the accelerator pedal 5.

The brake motor driver 13 supplies a drive current corresponding to a braking instruction signal output from the controller 9 to the brake motor 14 during automatic traveling. As a result, the brake motor 14 drives the drum brakes 8a to 8d provided on each of the four wheels 2a to 2d via the gear 23 and the switching mechanism 20 to brake the vehicle. Further, in order to ensure safety, the brake pedal 7 is in a state of being connected to the drum brakes 8a to 8d through the switching mechanism 20 even during automatic traveling, and control by manual operation is also possible. .

The electromagnetic brake 15 is a brake device for stopping, which is on / off controlled by the controller 9, and is spline-fitted to a rotary shaft 24 for transmitting the rotation of the engine 1 to the transmission 3 as shown in the figure. And a fixed plate 15b fixed to the outer wall or the like of the transmission 3 so as not to contact the rotating shaft 24 and to face the disk 15a. Since the disk 15a is spline-fitted to the rotary shaft 24, the disk 15a rotates integrally with the rotary shaft 24 while being movable in the axial direction of the rotary shaft 24. In addition, fixed board 1
5b is composed of a permanent magnet that generates a magnetic field that attracts the disk 15a, and an electromagnet that is excited by the controller 9 so as to cancel the magnetic field of the permanent magnet.

That is, in the electromagnetic brake 15, the excitation of the electromagnet is turned on during traveling, and the magnetic field of the permanent magnet is canceled by this magnetic field, so that the attraction force to the disk 15a disappears, and as a result, the rotating shaft 24 is rotated. On the other hand, braking is no longer effective. On the other hand, if the excitation to the electromagnet is turned off immediately before stopping,
The disk 15a is fixed to the fixed plate 15b by the magnetic force of the permanent magnet.
The rotary shaft 24 is braked.

Further, the controller 9 is the electromagnetic brake 1
If the configuration is such that the magnitude of the exciting current supplied to the electromagnet is made variable and the magnitude of the braking force to be applied to the vehicle is controlled, instead of simply controlling ON / OFF of 5, the electromagnetic force as an automatic traveling brake device is obtained. Drum brakes 8a to 8d driven by the brake 15 and the brake motor 14 described above.
It is possible to use and together. For example, the electromagnetic brake 15 is mainly used as a first system brake device for supplying a small braking force for speed control during traveling, and the drum brakes 8a to 8d are mainly supplied with a large braking force for stopping the vehicle. You may make it use as a brake system of a 2nd system.

The guide wire sensor 16 is attached to a T-shaped arm 25 attached to the front end of the vehicle so as to be horizontally rotatable.
It is placed in three places so as to face the ground. The guide wire sensor 16 magnetically detects a guide wire (not shown) embedded in a golf course or the like, and outputs a detection signal to the controller 9 according to the distance from the guide wire. The controller 9 controls the traveling of the vehicle based on the output of the guide wire sensor 16 so that the vehicle does not depart from the course.

The fixed point sensor 17 is attached to a predetermined position of the vehicle so as to face the ground, and magnetically defines a fixed point composed of a plurality of permanent magnets (not shown) embedded at a predetermined interval in a golf course or the like. To detect. For example, if this fixed point is composed of the magnetic poles of three permanent magnets, and the arrangement thereof is S pole, N pole, and N pole, the fixed point sensor 17
Outputs a detection signal corresponding to the pattern of the arrangement of the magnetic poles to the controller 9. The pattern of the arrangement of the magnetic poles is used as an instruction signal for the controller 9 to control traveling of the vehicle such as stop, start, and speed.

The operation panel 26 is provided in the vicinity of the driver's seat, and in addition to the main switch, a manual / auto switch for instructing switching between manual traveling and automatic traveling, and start / stop for instructing starting and stopping. It is composed of various switches such as switches and a display section for displaying a warning. When automatic running is selected by the manual / auto switch on the operation panel 26, the controller 9
Switches the traveling mode of the vehicle from manual traveling to automatic traveling, and performs control for automatic traveling described later.

In addition, as a sensor group for detecting the running state of the vehicle, a vehicle speed sensor 30 for detecting the vehicle speed in the transmission 3, a throttle potentiometer 31 for detecting the throttle opening in the engine 1, a steering driver 10 and a brake motor driver 13 are provided. Are the thermistors 32 and 33 that detect the respective temperatures, the brake motor driver 13 is a current sensor 34 that further detects the amount of current supplied to the brake motor 14, and the gear 23 is the brake motor 14 due to an abnormality in the mechanical brake mechanism or the like. A brake limit switch 35 for detecting whether or not the rotation speed exceeds a certain limit value is provided.

Configuration of Controller 9 Next, the configuration of the controller 9 will be described. The controller 9 is composed of hardware such as a CPU (central processing unit) and a memory, and its software configuration has a target vehicle speed setting unit 91, a driving force calculation unit 92, a throttle drive calculation, as shown in FIG. Unit 93, braking force calculation unit 94, braking state switching determination unit 95, current command value calculation unit 9
6, excitation voltage calculation unit 97, abnormality determination / abnormality processing unit 98,
It is composed of input interfaces 99a to 99g for taking in various sensor outputs and switch outputs, and output interfaces 99h to 99l for outputting control signals such as various command values to the outside.

The target vehicle speed setting unit 91 outputs the set value of the target vehicle speed based on the speed instruction information read from the memory in response to the instruction signal supplied from the fixed point sensor 17 when the operation panel 26 is instructed to start. To do. Driving force calculator 9
2 calculates the necessary driving force to be applied to the vehicle based on the difference between the target vehicle speed setting value and the current vehicle speed detection value output from the vehicle speed sensor 30 installed in the transmission 3.

The throttle drive calculation unit 93 outputs an on / off instruction signal for the throttle clutch 19 according to the traveling mode, and based on the above calculation result of the required driving force and the detection result of the throttle opening degree by the throttle potentiometer 31. A throttle drive pulse corresponding to the drive amount of the throttle motor 12 is output.

The braking force calculation unit 94 calculates the required braking force based on the difference between the set value of the target vehicle speed and the current vehicle speed detection value and the amount of current supplied to the brake motor 14 detected by the current sensor 34.

The braking state switching determination unit 95 determines whether or not the braking state is appropriate based on the difference between the set value of the target vehicle speed and the current vehicle speed detection value and the detection result of the throttle opening, and the determination is made. The result is output to the braking force calculation unit 94. That is, if the throttle opening is in the accelerating state even though the vehicle speed is almost equal to the target vehicle speed, it means that the balance is maintained by simultaneously accelerating and braking. This will cause waste and wear of the brake shoes. Here, a determination is made to avoid such an inappropriate braking state.

The braking force calculation unit 94 outputs the calculated required braking force as it is to the current command value calculation unit 96 if the result of the determination is an appropriate braking state. On the other hand, if the result of the determination is an inappropriate braking state, the required braking force is gradually decreased until it becomes “0” and is output to the current command value calculation unit 96. Along with this, the throttle opening gradually becomes an appropriate value, and the inappropriate balance state is released.

The current command value calculation unit 96 includes a braking force calculation unit 9
Based on the value of the required braking force calculated by 4, the current command value to be given to the brake motor driver 13 is output. The excitation voltage calculation unit 97 outputs a binary signal instructing either on or off when the electromagnetic brake 15 is used only as an on-off type parking brake, but when the braking force by the electromagnetic brake 15 is variable. The excitation command value to be given to the electromagnetic brake 15 is output based on the value of the braking force output from the braking force calculation unit 94.

The abnormality determination / abnormality processing unit 98 is provided with the temperature detection values of the thermistors 32 and 33 provided in the steering driver 10 and the brake motor driver 13, the output of the brake limit switch 35, the current vehicle speed detection value, and the necessary control value. An abnormality determination is made based on the power calculation result. When it is determined that the vehicle is abnormal, a vehicle stop processing instruction is issued. The current command value calculation unit 96, the excitation voltage calculation unit 97, and the throttle drive calculation unit 93 receive the above stop processing instruction and output a value for stopping the vehicle.

(2) Operation of the Embodiment Next, the operation of this embodiment will be described. FIG. 3 is a flowchart showing the operation of the throttle opening control performed by the controller 9 during automatic traveling. Further, FIG. 4 is a flowchart showing the operation of the braking control performed by the controller 9 during the automatic traveling. In the following, referring to these flowcharts, the operation of the slot opening control and the braking control by the controller 9 is performed when the vehicle is approaching a flat road from a downhill as shown in FIGS. (E) ~
An example will be described in which the vehicle is approaching an uphill to a flat road as shown in (H).

Operation of throttle opening control <a> When the vehicle approaches a flat road from a downhill (Fig. 5)
(A) to (D)) First, in step Sa1 (see FIG. 3), the controller 9 determines the current running load of the vehicle. Here, the traveling load means the resistance that tends to hinder the traveling of the vehicle as described above, and is small when traveling on a downhill and large when traveling on an uphill.

For example, when the vehicle travels uphill, the vehicle speed, the engine speed and the gear ratio (ratio between the engine speed and the vehicle speed) vary as shown in FIGS. 6 (a) to 6 (c). In the present embodiment, when both the engine speed and the gear ratio (ratio of engine speed and vehicle speed) related to the running load exceed a predetermined threshold value (judgment value), it is determined that the engine load is high, and The up flag is set to "1" during the load (FIG. 6 (d)).

On the other hand, when the vehicle travels downhill, the vehicle speed, the braking force command value (required braking force) and the gear ratio change as shown in FIGS. 7 (a) to 7 (c). In the present embodiment, when the required braking force related to the running load exceeds a predetermined threshold value (determination value) and the gear ratio falls below the predetermined threshold value, it is determined that the load is low, and the low load is determined. During this period, the down flag is set to "1" (Fig. 7 (d)).

Now, as shown in FIG. 5 (A), when the vehicle is traveling on a downhill, the traveling load is small, so the controller 9 determines that the load is low (at this time, the down flag is “1”), the process proceeds to step Sa2. In step Sa2, the current vehicle speed is offset from the vehicle speed command value (target vehicle speed) by a predetermined offset value (for example, 1.5 km /
It is determined whether it is smaller than the value obtained by subtracting h). That is, a sudden change in vehicle speed (in this case, a sudden decrease in vehicle speed due to approaching a flat road) is detected. Here, when the vehicle is not yet approaching a flat road, the vehicle speed does not change suddenly, so the result of this determination is "No", and the determination in step Sa1 is repeated.

On the other hand, when the vehicle approaches a flat road as shown in FIG. 5B, the vehicle speed suddenly decreases,
The determination result of step Sa2 is “Yes”, and the process proceeds to step Sa3. In step Sa3, the throttle opening is rapidly increased to a predetermined large opening (a value slightly smaller than full opening). This prevents the vehicle from being suddenly reduced in speed due to the acceleration applied to the vehicle and the vehicle approaching a flat road (that is, due to a sudden increase in load). After the throttle opening is rapidly increased, the opening command value larger than the opening is accepted but the opening command value smaller than the opening is not accepted.

Then, in step Sa4, whether the current running load is still low (that is, the down flag is "1") and the current vehicle speed is still smaller than the target vehicle speed minus the offset value. Determine whether or not. That is, the vehicle has not yet reached the flat road (see FIG. 5).
(Positions (B) to (C)) and the above step Sa3
If the effect of acceleration due to the above does not sufficiently appear in the vehicle speed, the result of this determination is “Yes”, and the operations of steps Sa1 to Sa4 described above are repeated again.

On the other hand, when the vehicle reaches a flat road (positions in FIGS. 5C to 5D) and the down flag becomes "0", or the acceleration effect by the step Sa3 sufficiently appears at the vehicle speed. When the current vehicle speed becomes larger than the value obtained by subtracting the offset value from the target vehicle speed, the determination result of step Sa4 becomes "No", and the process proceeds to step Sa5. In step Sa5, the throttle opening is set to a normal command value (that is, a command value for medium load) corresponding to the difference between the vehicle speed detection value and the target vehicle speed, and thereafter, speed control on a normal flat road is performed.

<B> When the vehicle is approaching a flat road from an uphill (FIGS. 5 (E) to (H)) As shown in FIG. 5 (E), when the vehicle is traveling on an uphill, the running load Is large, the controller 9 determines that the load is “high” in step Sa1 (at this time, the upstream flag is “1”), and the process proceeds to step Sa6.

In step Sa6, it is determined whether or not the current vehicle speed is higher than the target vehicle speed plus a predetermined offset value. That is, also in this case, similarly to the above, a sudden change in vehicle speed (in this case, a rapid increase in vehicle speed due to approaching a flat road) is detected. Here, if the vehicle is not yet approaching a flat road, the vehicle speed does not change suddenly, so the result of this determination is "No", and the determination in step Sa1 is repeated as described above.

On the other hand, when the vehicle approaches a flat road as shown in FIG. 5 (F), the vehicle speed suddenly rises.
The determination result of step Sa6 is “Yes”, and the process proceeds to step Sa7. In step Sa7, the throttle opening is set to a predetermined small opening (a value slightly larger than the opening when flat).
Sharply decrease to. As a result, the acceleration applied to the vehicle is sharply reduced, and the rapid increase in speed due to the approach to the flat road (that is, the rapid decrease in load) is prevented. After the throttle opening is sharply reduced, the opening command value smaller than the opening is accepted, but the opening command value larger than the opening is not accepted.

Then, at step Sa8, whether the current running load is still high (that is, the ascending flag is "1"), and the current vehicle speed is still larger than the target vehicle speed plus the offset value. Determine whether or not. That is, the vehicle has not yet reached the flat road (see FIG. 5).
(Positions (F) to (G)) and the above step Sa7
If the effect of deceleration due to is not yet sufficiently exhibited in the vehicle speed, the result of this determination is "Yes", and the operations of steps Sa1 and Sa6 to Sa8 described above are repeated again.

On the other hand, when the vehicle reaches a flat road (positions (G) to (H) in FIG. 5) and the up flag becomes "0", or the effect of deceleration by the above step Sa7 sufficiently appears at the vehicle speed. When the current vehicle speed becomes smaller than the value obtained by adding the offset value to the target vehicle speed, the determination result of step Sa8 becomes "No", and the process proceeds to step Sa9. In step Sa9, the throttle opening is set to a normal command value corresponding to the difference between the vehicle speed detection value and the target vehicle speed, and thereafter, speed control on a normal flat road is performed.

Operation of Braking Control Next, the operation of the braking control will be described. <a> When the vehicle approaches a flat road from a downhill (Fig. 5)
(A) to (D)) First, in step Sb1 (see FIG. 3), the controller 9 determines the current running load of the vehicle, as in the case of the throttle opening control described above.

Then, as shown in FIG. 5 (A), when the vehicle is traveling on a downhill, the traveling load is small, so the controller 9 determines that the load is low (at this time, the down flag is "1"), and the process proceeds to step Sb2.
In step Sb2, it is determined whether or not the current vehicle speed is smaller than the value obtained by subtracting the offset value from the target vehicle speed, and a rapid change in vehicle speed (in this case, a rapid decrease in vehicle speed due to approaching a flat road) is detected. Here, when the vehicle is not yet approaching a flat road, the vehicle speed does not change suddenly, so the result of this determination is "No", and the determination in step Sb1 is repeated.

On the other hand, as shown in FIG. 5 (B), when the vehicle approaches a flat road, the vehicle speed suddenly decreases.
The result of the determination in step Sb2 is “Yes”, and the process proceeds to step Sb3. In step Sb3, a predetermined value d1 is subtracted from the value of the original required braking force corresponding to the difference between the detected vehicle speed and the target vehicle speed, and this result is set as the new required braking force. As a result, the braking force applied to the vehicle is sharply reduced, and the rapid reduction in speed due to the approach to the flat road (that is, due to the rapid increase in load) is prevented.

Then, in step Sb4, it is determined whether or not the current running load is still low (that is, whether or not the down flag is "1"). That is, when the vehicle has not completely reached the flat road and is in the position of FIGS. 5B to 5C, the determination result is “Yes”, and the operations of steps Sb1 to Sb4 described above are repeated. .

On the other hand, when the vehicle reaches a flat road (see FIG.
(Positions (C) to (D)), the determination result of the step Sb4 is "No", and the process proceeds to step Sb5. In step Sb5, the required braking force is set to a normal command value (that is, a command value for medium load) corresponding to the difference between the vehicle speed detection value and the target vehicle speed, and thereafter, braking control on a normal flat road is performed.

<B> When the vehicle is approaching a flat road from an uphill (FIGS. 5 (E) to (H)) As shown in FIG. 5 (E), when the vehicle is traveling uphill, the running load Is large, the controller 9 determines that the load is “high” in step Sb1 (the up flag is “1” at this time), and the process proceeds to step Sb6.

In step Sb6, it is determined whether or not the current vehicle speed is greater than the target vehicle speed plus a predetermined offset value. That is, also in this case, similarly to the above, a sudden change in vehicle speed (in this case, a rapid increase in vehicle speed due to approaching a flat road) is detected. Here, if the vehicle is not yet approaching a flat road, the vehicle speed does not change suddenly, so the result of this determination is "No", and the determination in step Sb1 is repeated as described above.

On the other hand, when the vehicle approaches a flat road as shown in FIG. 5 (F), the vehicle speed suddenly increases.
The determination result of step Sb6 is “Yes”, and the process proceeds to step Sb7. In step Sb7, a predetermined value d2 is added to the value of the original required braking force corresponding to the difference between the detected vehicle speed and the target vehicle speed, and the result is used as the new required braking force. As a result, the braking force applied to the vehicle is sharply increased,
A sudden increase in speed due to approaching a flat road (ie due to a sudden decrease in load) is prevented.

Then, in step Sb8, it is determined whether or not the current running load is still high (that is, whether or not the upstream flag is "1"). That is, when the vehicle has not completely reached the flat road and is in the position of FIGS. 5F to 5G, the determination result is “Yes”, and the operations of steps Sb1 and Sb6 to Sb8 described above are performed again. repeat.

On the other hand, when the vehicle reaches a flat road (see FIG.
(Positions (G) to (H)), the result of the determination in step Sb8 is "No", and the process proceeds to step Sa9. In step Sa9, the required braking force is set to a normal command value corresponding to the difference between the vehicle speed detection value and the target vehicle speed, and thereafter, braking control on a normal flat road is performed.

(3) Summary As described above, according to the present embodiment, when the traveling load suddenly changes such as when the vehicle approaches a flat road from a downhill or approaches a flat road from an uphill, this load is changed. Is detected before the change in vehicle speed is detected, and the throttle opening and the braking force are sharply reduced or increased in order to prevent this change in vehicle speed. Therefore, overshoot caused by a change in running load (rapid increase in vehicle speed) And undershoot (rapid decrease in vehicle speed) can be dealt with quickly, and smooth running is possible.

In the case of braking control, the above-mentioned step S
In b4 and Sb8, the condition that "the vehicle speed falls within the range of the offset value from the target vehicle speed" is not a condition for returning to the braking control at the normal time. It's getting harder. This is because the braking control has a quicker response than the speed control based on the throttle opening, so that the condition for returning to the braking control at the normal time is made strict and the returning timing is delayed. As a result, it is possible to prevent the effect due to the sudden decrease or sudden increase in the braking force from being restored before the vehicle speed sufficiently appears.

On the other hand, in the case of the throttle opening control, even if the control is returned to the normal command value, the engine speed does not change immediately after the return. Need not be delayed. Therefore, the conditions for returning to the normal opening control as in steps Sa4 and Sa8 described above are relaxed.

(4) Modification Example In the above embodiment, the sudden change of the traveling load due to the up and down of the slope was described as an example, but the present invention is not limited to the above example, and other causes such as a sudden change of the vehicle weight. It is also applicable when the running load changes suddenly. Further, when the fluctuation of the traveling load is caused only by the ascending / descending of the slope, the inclination angle sensor (not shown) may be used for the determination instead of the determination of the traveling load as in the above embodiment. Good. In this case, for example, when the inclination angle is + 12 ° (up), it is determined that the load is high, and when the inclination angle is -12 ° (down), it is determined that the load is low.

Further, in the above embodiment, step Sa
Although the throttle opening is opened and closed to a predetermined set opening in Sa3 and Sa7, the opening and closing amount to be increased or decreased may be set instead of determining the set opening in this way.

[0065]

As described above, according to the present invention, the braking force and / or the throttle opening can be adjusted without delaying the fluctuation of the vehicle speed when the traveling load suddenly changes to prevent the fluctuation of the vehicle speed. As a result, it is possible to obtain the effect of smooth running.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an automatic vehicle according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a software configuration of a controller of the autonomous vehicle.

FIG. 3 is a flowchart for explaining an operation of throttle opening control by the controller.

FIG. 4 is a flowchart for explaining an operation of braking control by the controller.

FIG. 5 is a schematic diagram showing states when the vehicle approaches a flat road from a downhill ((A) to (D)) and when the vehicle approaches a flat road from an uphill ((E) to (H)). .

FIG. 6 is a graph showing changes in values of a vehicle speed, an engine speed, a gear ratio, and an up flag when the vehicle travels uphill.

FIG. 7 is a graph showing changes in the vehicle speed, the required braking force, the gear ratio, and the respective values of the down flag when the vehicle travels on a downhill.

[Explanation of symbols]

9 ... Controller (load detection means, braking command value control means, opening command value control means), 10 ... Steering driver, 11 ... Steering motor, 12 ... Throttle motor, 13 ... Brake motor driver, 14 ... Brake motor, 15 ... Electromagnetic brake, 30 ... Vehicle speed sensor (load detection means), 91 ... Target vehicle speed setting section, 92 ... Driving force calculation section, 93 ... Throttle drive calculation section, 94 ... Braking force calculation section, 95 ... Braking state switching determination section, 96 ... current command value calculation unit, 97 ... excitation voltage calculation unit, 98 ... abnormality determination / abnormality processing unit, 99a to 99l ... interface.

Claims (6)

[Claims] 1. A load detecting means for detecting a running load of a vehicle in an automatic vehicle which compares a detected vehicle speed with a target vehicle speed and controls a necessary braking force to be applied to the vehicle so that they match each other. In the case where the traveling load is high, when the vehicle speed detection value exceeds the target vehicle speed by a predetermined value or more, the command value of the required braking force is rapidly increased by a predetermined value, and the traveling load is low. An automatic traveling vehicle, further comprising: a braking command value control means for rapidly reducing the command value of the required braking force by a predetermined value when the vehicle speed detection value becomes smaller than the target vehicle speed by a predetermined value or more. 2. The command value of the required braking force is set as a vehicle speed detection value when the high or low state of the running load changes after the command value of the required braking force is suddenly increased or decreased by the braking command value control means. The automatic traveling vehicle according to claim 1, further comprising a returning means for returning to a normal control command value corresponding to a comparison result of the target vehicle speeds. 3. An automatic traveling vehicle that compares a vehicle speed detection value and a target vehicle speed, and travels while controlling the throttle opening so that they match each other. Load detection means for detecting a traveling load of the vehicle; When the vehicle speed detection value is higher than the target vehicle speed by a predetermined value or more in the case of a high load, the command value of the throttle opening is sharply reduced by a predetermined value, and the vehicle speed is reduced when the traveling load is a low load. An automatic traveling vehicle comprising: an opening command value control means for rapidly increasing the command value of the throttle opening by a predetermined value when the detected value becomes smaller than the target vehicle speed by a predetermined value or more. 4. When the high or low state of the traveling load changes after the opening command value control means suddenly decreases or increases the throttle opening command value, or when the vehicle speed detection value changes from the target vehicle speed. When it comes to fall within a predetermined value, a return means is provided for returning the command value of the throttle opening to a normal control command value corresponding to the comparison result of the vehicle speed detection value and the target vehicle speed. Item 3. The automated vehicle according to Item 3. 5. A load detection means for detecting a running load of a vehicle in an automatic vehicle that compares a detected vehicle speed with a target vehicle speed and controls a necessary braking force to be applied to the vehicle so that these values match each other. In the case where the traveling load is high, when the vehicle speed detection value exceeds the target vehicle speed by a predetermined value or more, the command value of the required braking force is rapidly increased by a predetermined value, and the traveling load is low. In addition, when the vehicle speed detection value is smaller than the target vehicle speed by a predetermined value or more, a braking command value control unit that sharply reduces the command value of the required braking force by a predetermined value, and when the traveling load is a high load, When the vehicle speed detection value is higher than the target vehicle speed by a predetermined value or more, the throttle opening command value is rapidly reduced by a predetermined value, and when the traveling load is low, the vehicle speed detection value is higher than the target vehicle speed. An automatic travel vehicle comprising: an opening command value control means for rapidly increasing the command value of the throttle opening by a predetermined value when it becomes smaller than a predetermined value. 6. The command value of the required braking force is set as a vehicle speed detection value when the high or low state of the running load changes after the command value of the required braking force is suddenly increased or decreased by the braking command value control means. First returning means for returning to a normal control command value corresponding to the comparison result of the target vehicle speed, and the opening command value control means, after the command value of the throttle opening is suddenly decreased or rapidly increased, the traveling load is increased or decreased. When the state changes, or when the vehicle speed detection value comes to fall within a predetermined value from the target vehicle speed, the throttle opening command value is set to a normal value corresponding to the comparison result of the vehicle speed detection value and the target vehicle speed. 6. The automatic traveling vehicle according to claim 5, further comprising a second returning means for returning to the control command value of.