JPH02205904A - Automatic driving controller for vehicle - Google Patents

Abstract

PURPOSE:To accurately perform the automatic driving by performing the control to correct the forecast error in a position of a prescribed extent forward and correcting the manipulated variable of a programmed actuator in accordance with the vehicle speed, the steering angle, and the extent of turn of the vehicle body. CONSTITUTION:A forecast error operating means 16 successively operates the forecast error for running from the present position to a position of a prescribed extent forward in accordance with sensor information, and this forecast error is used as the feedback value of the manipulated variable. Meanwhile, an extent of correction of the steering angle or the like is operated in a correction operating means 17 in accordance with the vehicle speed, the steering angle, and the extent of turn of the vehicle body out of sensor data, and the manipulated variable of the program is corrected by this extent of correction. The feedback value of the forecast error is given to the corrected manipulated variable to output the final actuator manipulated variable. The extent of correction corrects the deviation from a course due to running on a steady circle. Thus, the vehicle is stably run with a high precision though circumstances such as a friction coefficient mu of the road surface are changed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic pilot control system for a vehicle, and particularly to control contents of an automatic pilot control system for automatically driving a vehicle along a predetermined taxiway. be.

[Prior Art] Automated vehicles that automatically travel along a predetermined course are well known, and are used in unmanned guided vehicles in factories, endurance tests, and the like. This self-piloted vehicle, for example, installs a guidance cable on a predetermined course, detects the position of this guidance cable with a magnetic field sensor, and operates the steering wheel, accelerator, brakes, etc. using actuators, and automatically travels along the guidance cable. This makes it possible to drive the vehicle faithfully to the course.

In the past, as shown in Japanese Unexamined Patent Publication No. 63-3315, information necessary for setting a running course has been provided in advance by running the actual course with manned control and collecting course information. be. According to this,
To enable smooth running without deviating from a predetermined course even on relatively complex terrain. Furthermore, there is a method disclosed in Japanese Patent Laid-Open No. 55-34793 that controls a moving object by following a predetermined route.

[Problems to be Solved by the Invention] However, in conventional vehicle autopilot systems, the vehicle is operated using a mechanically created program, so it is not possible to perform fine-grained driving like a human actually operating the vehicle. When transporting not only goods but also people, there is a problem of poor riding comfort.

In general, the most important thing for autopiloted vehicles is to follow the course faithfully, and because they use high-speed control with a relatively high feedback gain, they are very different from those operated by humans, and the stability of the control is poor. ing. Note that even in the case of the above-mentioned Japanese Patent Application Laid-Open No. 63-3315, only the course is taught and the amount of maneuver is not taught.

Furthermore, when used in endurance running tests, the results are somewhat different from actual human operation, and highly reliable test results are not necessarily obtained.

Furthermore, when the types of vehicles are different, the maneuverability of the vehicle changes, and the same control may not be able to handle the change. However, in the past, without distinguishing between vehicle types,
Since steering control is performed using a predetermined program, there is a problem in that some vehicles may go off the course. Furthermore, when transporting people, different controls are required depending on the type of vehicle, and standard control is insufficient.

Therefore, the applicant calculates the prediction error that occurs at a predetermined distance from the current position of the vehicle, and adds the motion gain (
It is proposed that the amount of error correction be obtained by multiplying the amount of error (feedback gain), and this correction amount be fed back to the amount of operation of the actuator to operate the steering, etc., to perform automatic steering with good followability and stability.

However, when driving around a curve (steady circular turn), if the friction coefficient μ of the road surface changes due to rough roads, etc., or if the vehicle cannot travel at the target speed, the cornering force of the front and rear wheels changes and the vehicle steering characteristics change. As a result, the turning radius of the vehicle for a constant steering angle changes, causing a problem of course deviation.

The applicant has also proposed that the driver teaches the course and the amount of actuator operation to achieve vehicle operation similar to that actually driven by a human, but in this case as well, the driver teaches the program control value. If the driving conditions at the time of initial setting and the driving conditions during actual driving differ due to changes in the environment, course deviation will occur during steady circular turning.

The present invention was made to solve the above-mentioned conventional problems, and its purpose is to enable highly accurate and stable automatic steering even when environmental conditions change during steady circular turns. The object of the present invention is to provide a vehicle automatic steering control device.

[Means for Solving the Problems] In order to achieve the above object, the present invention measures the current position and running state of the vehicle with respect to the taxiway, and adjusts each actuator for automatic steering based on this position and running state. In a vehicle autopilot system that operates and controls the taxiway, there is a storage means for storing the taxiway and the amount of operation of each actuator when driving on the taxiway, and the vehicle moves a predetermined distance from the current position according to the contents of the storage means. a prediction error calculation means for calculating a prediction error when traveling; a correction calculation means for correcting the operation amount stored in the storage means based on the vehicle speed, steering angle, and amount of vehicle body turning; and an output from the correction calculation means. The actuator operation amount calculating means corrects the corrected operation amount by the prediction error to calculate the actuator operation amount.

The vehicle body turning amount, which is a calculation element in the correction calculation means, includes a yaw rate, a turning radius, and the like.

[Operation] According to the above configuration, the taxiway stored in the storage means is automatically operated by the actuator according to the operation amount stored in the same manner, but at this time, the position and position of the vehicle are detected from various sensors. The driving condition is detected. and,
Based on this sensor information, the prediction error calculation means successively calculates a preliminary tP1 error when the vehicle travels a predetermined distance from the current position, and this prediction error is used as a feedback value of the manipulated variable.

On the other hand, the correction calculation means calculates a correction amount for the steering angle, etc. from the vehicle speed, steering angle, and vehicle body turning amount among the sensor data, and the program operation amount is corrected by this correction amount. Then, by giving the feedback value of the prediction error to this corrected operation amount, the final actuator operation amount is output. The correction amount is for correcting course deviation that occurs when traveling in a steady circular turn,
This makes it possible to drive with good accuracy and stability even when there are changes in the environment such as the coefficient of friction μ of the road surface.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an arithmetic processing block circuit of a vehicle autopilot control device according to a first embodiment, and FIG. 2 shows a specific configuration of the autopilot vehicle.

In the first embodiment, the target course is a taught taxiway, and when the target course is automatically steered, the operation amount is corrected based on the vehicle speed, steering angle, and yaw rate (one of the vehicle body turning amounts). To specifically explain the configuration of the autopilot vehicle with reference to FIG. 2, in order to detect the lateral deviation of the vehicle, a front magnetic field sensor 110a, a front lateral deviation detection circuit 111a, a rear magnetic field sensor 110b, and a rear deviation detection circuit 111b are used. is provided, and detects the magnetic field output from the induction cable 20 provided in the guideway to determine the lateral deviation and the yaw angle.

That is, as shown in Fig. 4, the lateral deviation of the front part is
If the lateral deviation Y of the rear part of r1 is ``, then the center position of the vehicle 28 is 0.
The lateral deviation Y at is Y − (Yf + Yr) /2 − (1)
And if the length of the vehicle is a, then the yaw angle θ of the vehicle is
is θ-(Yf-Yr)/a-(2).

Although not shown, the yaw rate (yaw angular velocity) γ can be determined from the yaw angle using a yaw rate sensor using the following equation.

γ−dθ/dt −(θ−θ)/Δt (θ−1 is the previously detected yaw angle) (3) In addition, a magnetic pickup 114 is provided to determine the vehicle speed, and the magnet rotation plate 113 is Vehicle speed is detected by detecting the rotational speed.

An antenna 115 and a reference position detection circuit 116 are provided to detect the position of the vehicle on the taxiway, and the antenna 115 receives radio waves output from position beacons provided at each predetermined point on the taxiway. By supplying the signal to the reference position detection circuit 116, the reference position on the course can be detected.

In addition, an arithmetic geographical circuit (ECU) 24 is used to input detection signals etc. from the various sensors mentioned above and perform various arithmetic processing.
A feedback processing circuit 26 is provided which performs predetermined processing by feeding back the operating amounts of various actuators that operate the vehicle, and these processing circuits have a configuration as shown in FIG. 3 on the hardware of the microcomputer.

Various actuators provided in the vehicle 28 for automatic steering include the illustrated drive motor 29.
In addition to the steering wheel 30, an accelerator, a brake, etc. are provided, and the amounts of these operations are detected by sensors provided in various actuators, such as the steering amount sensor 32, and fed back.

In this embodiment, the taxiway is automatically steered along a target course taught by a human, so a manual switch 34 for switching between the taught driving mode and the automatic driving mode and an indicator lamp 36 for identifying this mode state are provided. ing.

In FIG. 1, a target course map 14a and a manipulated variable map 14b are provided as storage means, but since the first embodiment is for automatically piloting a taught target course, the target course map 14g includes a position Information on the position glX detected from the beacon 22, etc., and the lateral deviation Y0 and yaw angle θ during teaching operation at this position X. is the averaging section 24
1 and stored. Lateral deviation Y in this case.

The yaw angle θ0 is a value measured with reference to the guideway rather than the target course, and in the embodiment, it is a value measured from the guide cable 20. In this way, if a target course is taught for a predetermined taxiway, there is an advantage that the actual travel course can be freely determined for the taxiway.

In the operation amount map 14b, the operation amounts when the driver operates various actuators during the teaching driving are averaged by the averaging section 242 and stored. for example,
The steering angle, accelerator amount, and brake amount for driving the vehicle at each position on the taxiway are stored, and this storage means 14
Autopilot control is performed according to the program b.

Additionally, an adder/subtractor 161.1 is used as the prediction error calculation means 16.
62, an error calculation section 163 and a gain multiplier 164 are provided, and an adder 18 is provided as an actuator operation amount calculation means.
is provided.

For example, when the vehicle is running in the state shown in FIG. 5, the following calculations are performed.

In Figure 5, the target course 800 is automatically traveled.
The vehicle 28 is away from the target course by Δ,i! The vehicle travels at the current position shown in the diagram m (tW deviation) away, and the yaw angle of the vehicle at this time is Δθ
It is. This yaw angle is the tangent line 801 (801
In this state, normal feedback control would give a steering angle to correct Δj!m, but in the present invention, the predicted error amount Lm ahead is calculated. The distance ML is preferably 10 to 20 m.

That is, since the current yaw angle of the vehicle is Δθ, Lm
In the future, a new error of L·Δθ (Δθ is small and sinΔθ is assumed to be Δθ) will occur, and the final prediction error ε0 for Lm ahead will be ε. −Δl−LΦΔθ ・・
- (4), which is performed by the error calculation unit 163.

In order to use the lateral deviation and yaw angle, which are information for calculation in this case, as values based on the guide cable (guideway), the current detected values are added to the output of the target course map 141 using the adder/subtractor 161.
．． 162 will be added and subtracted. That is, the above (4
) in the equation is Δ1-Y, -Y, and Δθ is Δθ-θ. −
becomes θ. Then, the prediction error ε obtained by the error calculation unit 163. is the motion gain Kp by the gain multiplier 164
is multiplied, and the final error correction amount ΔU is ΔumKpε
. ...(5), which is output to the adder 18 which is actuator operation amount calculation means.

A characteristic feature of the present invention is that the actuator operation amount stored in the operation amount map is corrected according to changes in environmental conditions. A correction calculation means 17 consisting of an extraction steering angle calculation section 172 is provided.

That is, in the present invention, the operation amount is corrected based on the vehicle speed, the steering angle, and the amount of vehicle body turning, and this correction can be performed by taking into account, for example, the stability factor (characteristic representing the turning performance of the vehicle).

Stability factor A of a vehicle making a steady circular turn
and yaw rate r1 stability factor A and turning radius ρ
The relationship can be expressed by the following equation.

7- [1/ (1+AV2)] (V/J++)
61)-(1+AV2) (,l!o/δ)
−(7) However, v: vehicle speed, i,; wheel base, δ
: Steering angle.

In the first embodiment, focusing on the yaw rate γ and using the above equation (6), the stability factor A is determined by the following equation.

A-((Vδ/j!o 7) 1)/V2- (8
) In FIG. 1, the stability factor is calculated in the stability factor calculation unit 171, and the stability factor A calculated at the time of driver teaching is stored in the manipulated variable map 14b via the averaging unit 242. Note that in the above equation, the yaw rate γ is calculated by the yaw rate calculating section 243.

On the other hand, during actual driving, the calculated stability factor A'' is supplied to the correction steering angle calculation section 172, where the correction value δ1. of the steering angle (operation amount) is calculated. ) is transformed into δ−t −(1
+A"V")(J!n/ρ)++ (9), and the amount of correction of the steering angle can be found using equation (9).

Note that the turning radius ρ in the above equation (9) is determined by the turning radius calculating section 24.
4, the stability factor calculation unit 171
It is calculated from the stability factor A1 steering angle δ and speed V output from the above equation (7).

The steering angle correction amount δ1 calculated in this way. ,teeth,
The error amount ΔU is output as the steering angle of the steering wheel 30 to the adder 18 and output from the prediction error calculation means 16.
The adder 18, which is the actuator operation amount calculation means, calculates the final steering angle u (t)
, u (t)−δyet+ΔU (10)
is outputted, and is outputted to the actuator side via the sample hold circuit 19.

To explain Fig. 5, ε shown in the figure is the amount of deviation from the target course 800 when traveling at the current steering angle, and this ε can be resolved by steering from the current position at the taught steering angle. However, if environmental conditions such as the friction coefficient μ of the road surface and the vehicle speed change, the steering angle stored in the operation amount map 14b will deviate from the course. However, in the present invention, since this steering angle is corrected in accordance with changes in environmental conditions, the above-mentioned ε at a distance Lm ahead.

It is possible to accurately perform operation to eliminate the amount. Therefore,
By correcting the prediction error, it becomes possible to accurately automatically travel on the target course 800.

Note that the prediction error calculation means 16 and the correction calculation means 1 in FIG.
7 and the actuator operation amount calculation means can be constituted by the calculation processing circuit 24 and the feedback processing circuit 26 shown in FIG.

In FIG. 1, only the steering angle was explained as the manipulated variable, but the accelerator actuator and the brake actuator are controlled so that the vehicle speed is the one stored in the manipulated variable map 14b.
It is preferable to correct not only the steering angle but also the vehicle speed in the same way, thereby achieving good automatic steering.

The embodiment has the above configuration, and its operation will be explained below.

FIG. 7 shows the overall operation of the control contents. First, in step 61, necessary data such as the vehicle's wheel base etc. are input manually to perform initial settings, and the process proceeds to step 62.

In this step 62, the position and running state of the vehicle are detected while the vehicle is running, including the vehicle position X, vehicle speed V, and steering angle δ.
, yaw rate γ, throttle opening θlb, and lateral deviation Y are detected, and the process proceeds to step 63.

In this step 63, it is determined whether or not the driver is in the teaching state using the manual switch 34 (FIG. 2).
If “No”, the process moves to step 68; if “YES”, the process moves to step 64. In this step 64, the detection value obtained in the step 62 detected during driving by the driver is read, and the process proceeds to step 65, where a stability factor A focusing on the yaw rate is calculated using the above equation (8).

When proceeding to the next step 66, the turning radius calculating section 244 calculates the turning radius ρ shown in the above equation (7) using the obtained stability factor A, and step 67
Move to.

In this step 67, the calculation result is stored, but when storing the teaching data, the average value of several times is taken and stored as the target value, and finally the target turning at each position The radius ρ1, throttle opening θ, 1, and vehicle speed Vn are stored in the manipulated variable map 14b.

On the other hand, in the case of actual automatic driving after the driver instruction, the detection value of the driving state detected during driving is read in step 68, and the process proceeds to step 69, where the vehicle position
is detected based on the position beacon 22, and the next step 7
Transition to 0.

In this step 70, target turning radius ρ1, throttle opening θ1, etc. at each point stored in the manipulated variable map 14b are determined. is read out, and in the next step 71, the current stability value 9A''-(
(V"15"/JRr")-1)/V" is calculated.

Next, in step 72, the stability factor A is used to correct the steering angle and the throttle opening. That is, the corrected steering angle δtag is (1+
A"Vl'2) (j!o / 9) l::, is calculated, and the throttle opening θ1kral is θ+ht
mt-(1+VnVn')θ1. These values are output to the actuator operation amount calculation means in step 73.

FIG. 8 shows a second embodiment of the present invention, and this second embodiment is characterized in that the manipulated variable is corrected based on vehicle speed, steering angle, and turning radius. That is, the correction calculation means 17
' is composed of a stability factor and correction coefficient calculation unit 173 and a correction coefficient multiplication unit 174, and in the second embodiment, focusing on the turning radius and using the above equation (7), the stability factor A is determined by the following equation. .

A= (Cp δ/jo) 1)/V" = (
11) Then, the steering angle is calculated so that the turning radius ρ when taught by the driver is equal to the turning radius ρ5 during actual driving, and in this case, p = (1+AV”) (j!)l/ δ)=(
1+A"V")(JH/δ1..)-ρ6
...Since the relationship (12) holds true, 1+A"VI'2 δ2..- δ ...(13) 1+A
The corrected steering angle is determined by v2.

In the case of the second embodiment, the stability factor A is obtained from the course error Δρ without calculating the turning radius ρ, and the turning radius ρ8 during actual driving is stored in the manipulated variable map 14b. It can be determined by the turning radius ρ + Δρ, and AI−((ρ+ΔρI′)(ρ”#I()
-11.

Then, the formula (13) (') (1+AII ytz
)/(1+AV2) as a correction coefficient, and the correction coefficient multiplier 174 multiplies the steering angle δ by the correction coefficient K to obtain a corrected steering angle δ1. , outputs.

FIG. 9 shows the operation of the second embodiment. First, initial settings are made in step 81, and then the process proceeds to step 82, where vehicle position X, vehicle speed V, steering angle δ, 3-rate γ,
Throttle opening degree θ17. Detect the course error Δρ.

In step 83, it is determined whether or not it is driver instruction. If "NOo", the process moves to step 89; if "YES", the process moves to step 84. read the data,
In step 85, the course turning radius ρ7 is read out from the manipulated variable map, and in step 87, the turning radius ρ at that time is determined by ρ7+Δρ.

Then, in step 87, the stability factor A is calculated using the above equation (8), and the process moves to step 88, where the calculation result is stored. The teaching data in this case is the average value of several times and stored as a target value, and finally the turning radius ρ7 at each position Xn,
Throttle opening degree θ12 and vehicle speed Vn are the operation amount map 14b
is memorized.

On the other hand, when actually driving automatically after the driver instruction, the detected value of the driving state detected during driving is read at each predetermined vehicle position in step 89, and the course turning radius ρ is determined in step 90. Read out.

In the next step 91, the current turning radius ρ8 during actual driving is
is calculated, and the process proceeds to step 92 to calculate the current stability factor A*-(ρ8 (ρ"/jri-1)/Vn". In step 93, the target throttle opening θ is calculated.
1. Read out.

Then, in step 94, the steering angle is corrected using the stability factor A'', and the throttle opening is corrected. That is, the corrected steering angle δ1.l is ((1
+A"Vn")/(,1+AVn2)) δ, throttle opening θ1°1. , is θlbr*
1-(1+Vn-Vn') θ1°, and these values are outputted to the actuator operation amount calculation means in step 95.

In this way, in the embodiment described above, the actuator operation amount is corrected based on the detected value during actual driving.
Even if the coefficient of friction μ of the road surface or the actual vehicle speed changes during a steady circular turn on a rough road, the change can be corrected to prevent course deviation. In addition, since the actuator operation amount is determined by taking into account the prediction error at a predetermined distance,
The vehicle can be driven accurately on the target course and will not run off course.

Furthermore, by teaching and controlling the amount of operation of various actuators and performing prediction error correction control, it is possible to obtain the same riding comfort as when actually operated by a human, making it suitable for transporting not only objects but also people. Autopilot can be successfully applied.

[Effects of the Invention] As explained above, according to the present invention, control is performed to correct a prediction error for a predetermined distance ahead, and the programmed operation amount of the actuator is corrected based on the vehicle speed, steering angle, and vehicle body turning amount. As a result, even if the actual vehicle speed or the coefficient of friction μ of the road surface changes due to environmental conditions such as rough roads during steady circular turns, course deviation will not occur and accurate autopiloting can be achieved. This has the advantage of being possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention, FIG. 2 is a diagram showing a configuration when the present invention is applied to an actual autopilot vehicle, and FIG. 3 is a block diagram showing the configuration of a first embodiment of the present invention. An explanatory diagram showing the configuration when the processing circuit is performed by a microcomputer, Fig. 4 is an explanatory diagram showing how to obtain the lateral deviation with respect to the guideway, and Fig. 5 is an explanatory diagram showing the prediction error calculation performed according to the embodiment. 6 is a flowchart showing the operation of the first embodiment, FIG. 7 is a block diagram showing the schematic configuration of the second embodiment, and FIG. 8 is a flowchart showing the operation of the second embodiment. 14a ... 14b ... 16 ... 17 ... 18 ... 20 ... 22 ... 24 ... 26 ... 28 ... 30 ... 32 ... 36 ・... 163 ... 171 ... Target course map Operation amount map Prediction error calculation means Correction calculation means Adder as actuator operation amount calculation means Guidance cable position Beacon calculation processing circuit (ECU) Feedback processing circuit Vehicle steering steering amount sensor display Lamp error amount calculation section Stability factor calculation section 172 ... Correction steering angle calculation section 173 ... Stability factor and correction coefficient calculation section 174 ... Correction coefficient calculation section

Claims (1)

[Claims] (1) In a vehicle autopilot system that measures the current position and running condition of a vehicle with respect to a taxiway, and operates and controls each actuator for autopilot based on this position and running condition, the taxiway and the taxiway a storage means for storing the amount of operation of each actuator when driving the vehicle; a prediction error calculation means for calculating a prediction error when the vehicle travels a predetermined distance from the current position according to the contents of the storage means; a correction calculating means for correcting the operation amount stored in the storage means based on the angle and the amount of vehicle body turning; and correcting the correction operation amount output from the correction calculation means using the prediction error to calculate the actuator operation amount. An automatic steering control device for a vehicle, comprising: actuator operation amount calculation means.