JP3483855B2 - Vehicle-based traveling control method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic driving of vehicles such as general vehicles and work vehicles that require two or more wheels.
The present invention relates to a control method and an apparatus for traveling while accurately following a predetermined target trajectory without causing lateral deviation or azimuth deviation.

[0002]

2. Description of the Related Art When a vehicle such as a general vehicle or a work vehicle that requires two or more wheels is used to automatically perform a desired work, it is necessary for the vehicle itself to automatically follow a predetermined target trajectory. In this case, the target trajectory is not limited to a straight trajectory, and may have a curve in which various curvatures are mixed. Since it is not possible to deal with such a target trajectory by simply feeding back the lateral deviation and the azimuth deviation in a fixed coordinate system, a control method that can follow an arbitrary trajectory is required. Become.

As a conventional control method, for example,
"Vehicle Path Following Control Using Nonlinear Control Theory and Movement Planning-Vehicle Garage Control Using Switching" (Mitsuji Mihira et al.,
Journal of Japan Society for System Control Information, Vol. 6, No. 1,
pp. 37-47, 1993) are known. The relationship between the target trajectory and the traveling trajectory in this control method is as shown in FIG. 11, and when a control system is constructed based on this, the control system block diagram shown in FIG. 12 is obtained.

[0004]

However, the above-mentioned control method is a control method for a straight target trajectory, and cannot be applied to a target trajectory including a curve in which various curvatures are mixed. For target trajectories with various curvatures, observe the amount of lateral deviation and azimuth deviation from the target trajectory and the curvature of the target trajectory, and give the operation amount (steering angle) according to the deviation and curvature. However, it is not possible to cope with such a target trajectory by simply feeding back the lateral deviation and the deviation amount of the azimuth angle as described above.

The present invention has been made in view of the above points, and an object of the present invention is to change the curvature of a target track in automatic traveling of a vehicle such as a general vehicle or a work vehicle that requires two or more wheels. To provide a vehicle system travel control method and device capable of accurately following a target trajectory including a curve in which various curvatures are mixed by constructing a non-linear control system by introducing coordinate transformation in consideration of the above. It is in.

[0006]

In order to achieve the above-mentioned object, a traveling control method for a vehicle system according to the present invention is a method for controlling automatic traveling of a vehicle, in which an arbitrary target trajectory having a varying curvature is set. against it, on the target trajectory, a reference point such that the vehicle position is in the normal direction of the target track is provided, progress with respect to the reference point coordinate system from the absolute coordinate system of the vehicle position target trajectory
Convert to a relative coordinate system in which the direction and the normal direction are orthogonal , calculate the relative lateral deviation and azimuth deviation from the target trajectory, and use proportional control to determine the relative lateral deviation and azimuth angle.
The steering angle is determined based on a feedback operation amount according to the deviation amount of the above and a feedforward operation amount according to the curvature of the target trajectory and the lateral deviation amount relative to the target trajectory . In the above-described method of the present invention, the proportional-integral control is used instead of the proportional control, so that the steering angle (operation amount) can be determined in consideration of removing the steady deviation of the position from the target trajectory. it can.

Further, in the above method of the present invention,
If it is possible to directly detect the amount of lateral deviation and the amount of relative azimuth deviation with respect to the target trajectory, and if the curvature of the target trajectory can be detected or estimated, enter those values into the state quantity used for control. However, the steering angle (operation amount) can be determined. Furthermore, the curvature of the target trajectory of the vehicle wheelbase
When it is sufficiently smaller than the target trajectory, it is possible to detect and control only the relative lateral deviation amount and the azimuth angle deviation amount from the target trajectory.

The vehicle system traveling control device of the present invention is configured such that an input unit for inputting measurement / detection values of the position and azimuth of the vehicle and an input / output of the measurement / detection value of the steering angle for digital conversion. D conversion unit, map information of the target track, and the reference point such that the vehicle position is in the normal direction of the target track is provided to the target orbit, the coordinate system of the reference point as a reference from the absolute coordinate system of the vehicle position Proportional control or proportional / integral control is performed by converting into a relative coordinate system in which the traveling direction of the target trajectory and the normal direction are orthogonal to each other and calculating the relative lateral deviation and azimuth deviation from the target trajectory. The steering angle can be adjusted by the feedback operation amount according to the relative lateral deviation amount and the azimuth deviation amount, and the feedforward operation amount according to the curvature of the target trajectory and the relative lateral deviation amount from the target trajectory. Equipped with a program to calculate And憶means, measurement and the detected position of the vehicle
The vehicle position information consisting of position and azimuth and storage means.
A calculation means for executing a calculation based on a program from the stored map information of the target trajectory, and a steering angle output calculated from the calculated steering angle command value and the measured / detected value of the steering angle are converted into an analog signal and output. It is characterized in that it includes a D / A conversion means (see FIG. 8).

Further, the device of the present invention is an input means for inputting the measured / detected values of the relative lateral deviation amount and the azimuth angle deviation amount from the target trajectory of the vehicle and the detected value or estimated value of the curvature of the target trajectory. When the a / D converting means which is digitally converted measurement and the detected value of the steering angle is inputted, the relative lateral shift amount and shift amount or these relative azimuth angle proportional control or proportional-integral from the target track Relative lateral deviation and direction by control
A storage unit having a program for calculating a steering angle based on a feedback operation amount according to an angular deviation amount and a feedforward operation amount according to a curvature of the target trajectory and a relative lateral deviation amount from the target trajectory. And a calculation means for executing a calculation based on a program from the relative lateral deviation amount and azimuth deviation amount from the target trajectory and the curvature of the target trajectory, and the calculated steering angle command value and the measured / detected value of the steering angle. It is characterized in that it includes D / A conversion means for analog-converting and outputting the steering angle output calculated from and (see FIG. 9).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented. . (1) Travel Control Method In the above-described conventional control method shown in FIG. 11, the target trajectory must be a straight line and the angle from the absolute coordinate system must be within 90 degrees. This is because the lateral shift amount is set in the Y-axis direction of the absolute coordinate system. Therefore, in order to correspond to an arbitrary target trajectory, the coordinate system is converted as follows. Figure 1
2 shows the relationship between the target trajectory and the travel trajectory in the absolute coordinate system, and FIG. 2 shows the relationship between the target trajectory and the travel trajectory after conversion of the coordinate system (vehicle coordinate system). In FIG. 1, the reference point is determined on the target track so that the vehicle position is in the direction normal to the target track. In FIG. 2, the X ′ axis represents the component movement distance parallel to the target track of the vehicle, and the Y ′ axis represents the deviation amount from the target track in the normal direction of the vehicle system.

When a control system is constructed based on these, the control system block diagram shown in FIG. 12 is obtained by the conventional control method described above, and the control system block diagram shown in FIG. 3 is obtained by the present invention. The conventional control method represented by the control system block diagram shown in FIG. 12 simply feeds back the lateral deviation amount y and the azimuth angle θ in a fixed coordinate system (absolute coordinate system). In, it is not possible to follow a target trajectory in which the azimuth angle of the vehicle body is 90 degrees or more. On the other hand, in the present invention, the control system is configured as shown in the block diagram of FIG. Hereinafter, the control method of the present invention will be specifically described. The coordinate system after linearization conversion of the vehicle motion is referred to as the vehicle coordinate system. The method of coordinate conversion is shown below. The vehicle motion without skidding shown in FIG.
It is represented by the following equation.

[0012]

[Equation 1]

Further, the coordinate conversion from the absolute coordinate system of the vehicle position to the reference point reference relative coordinate system is expressed by the matrix shown in Equation 2.

[0014]

[Equation 2]

As a result, when x0 = y0 = 0, the equation (3) is obtained, and the derivative of these equations (4) is obtained.

[0016]

[Equation 3]

[0017]

[Equation 4]

Here, when the reference point is determined so that the vehicle position is in the direction normal to the target trajectory, the following condition shown in equation 5 is obtained.

[0019]

[Equation 5]

Further, considering the amount of movement of each part during a minute time when traveling on a curve, it becomes as shown in FIG. At this time, in order to set the vehicle coordinate system to a desired coordinate system, it is necessary to satisfy the condition shown in Formula 6, and at this time, considering the change in the minute time dt, Formula A6 shown in Formula 6 becomes The formula shown is the formula A7 shown in Formula 8.

[0021]

[Equation 6]

[0022]

[Equation 7]

[0023]

[Equation 8]

Further, by comparing the equation A4-1 shown in the equation 4 with the equation A7 shown in the equation 8, the equation A8 shown in the equation 9 is obtained. By the way, the left side of the expression A8 shown in Expression 9 is the velocity of the reference point in the X′-axis direction.

[0025]

[Equation 9]

Since it is difficult to linearize the motion of the vehicle if the X'axis is made to completely coincide with the traveling direction of the target trajectory,
Here, the actual traveling direction of the vehicle is the X ′ axis. This is because the equation A8 shown in the equation 9 becomes like the equation 10 and does not become the equation 11.

[0027]

[Equation 10]

[0028]

[Equation 11]

Further, from the relationship shown in FIG. 5, the following equation 12 is obtained, and if dφ is sufficiently smaller than this, ta
Since ndφ = dφ, Equation 13 is obtained.

[0030]

[Equation 12]

[0031]

[Equation 13]

Further, dydφ is sufficiently small, and dydφ =
When it is set to 0, it becomes as shown in Expression 14. Here, minute time d
Considering the change at t, the formula shown in Formula 14 becomes the formula shown in Formula 15, that is, the formula A9 shown in Formula 16.

[0033]

[Equation 14]

[0034]

[Equation 15]

[0035]

[Equation 16]

Based on these conditions, the motion of the vehicle in the vehicle coordinate system is expressed by the following equation (17).

[0037]

[Equation 17]

Next, linearization is performed on the non-linear system represented by the equation A10 of the equation (17).

[0039]

[Equation 18]

Here, if ξ1 = y and ξ2 = tan ψ are set,

[0041]

[Formula 19]

From this, the linearized system (20) is obtained.

[0043]

[Equation 20]

Construction of Control System Control Method 1 (Proportional Control) In the control system shown in FIG. 3, the manipulated variable is defined as the following equation 21, and the control system is constructed.

[0045]

[Equation 21]

At this time, the steering angle α is expressed by the formula A shown in the equation 22.
From Equation 14, Equation A15 shown in Equation 23 is obtained.

[0047]

[Equation 22]

[0048]

[Equation 23]

Control Method 2 (Proportional + Integral Control) Further, when performing control by proportional + integral control, the manipulated variable is defined as in the following equation 24, and a control system is constructed.
However, yr is a target deviation amount from the X ′ axis and is 0 here.

[0050]

[Equation 24]

At this time, the steering angle α is expressed by the formula A shown in the equation 25.
From Equation 16, Equation A17 shown in Equation 26 is obtained.

[0052]

[Equation 25]

[0053]

[Equation 26]

(2) Simulation Results FIG. 6 shows simulation results in the conventional control system shown in FIG. Further, FIG. 7 shows a simulation result in the control system of the present invention shown in FIG. 3 described above. As shown in this result, in the conventional control method described above, the target trajectory cannot travel on a curve of 90 degrees or more, whereas in the control method of the present invention, even if such a target trajectory is used, It can follow well.

(3) Deviation (relative lateral deviation amount, relative azimuth angle) detection method When the position and azimuth angle of the vehicle can be detected in real time with the map of the target trajectory, in this case, in real time, absolute Information on the X direction displacement of the vehicle in the coordinate system, the Y direction displacement of the vehicle, and the azimuth angle θ of the vehicle can be measured, and the X direction displacement of the reference point, the Y direction displacement of the reference point, and the target at the reference point in the absolute coordinate system can be measured. Since the azimuth angle φ of the trajectory and the radius of curvature R of the target trajectory are known,
The above control method can be applied as it is.

When the relative position can be detected In the above control method of the present invention, the relative deviation amount is calculated from the map of the target trajectory in the absolute coordinate system and the position / azimuth angle of the vehicle, and the deviation amount is set to 0. However, if it is possible to detect the lateral offset amount y and the relative azimuth angle shift amount ψ directly with respect to the target trajectory and the curvature of the target trajectory can be estimated or detected, the state used for control You can enter those values in the quantity. Then, when the curvature of the target trajectory is small, that is, the radius of curvature R is large, L / in the above-described equation A15 (in the case of proportional control) and equation A17 (in the case of proportional + integral control) shown in equation 26 (R
If the value of −y) is sufficiently negligible, the control can be performed only by detecting the lateral deviation amount y and the relative azimuth deviation amount ψ directly with respect to the target trajectory.

(4) Device Configuration of Control Device FIG. 8 is a device configuration diagram of the control device having a map of a target trajectory and capable of detecting the position and azimuth of the vehicle in real time. As shown in FIG. 8, the control device 10 uses the GPS
A signal interface 12 into which the vehicle position (displacement in the X and Y directions) and azimuth angle θ measured and detected by, for example, is input as vehicle position information, and an actual steering angle value α is input and digitally converted. A / D converter 14, memory 16 in which map information of the target trajectory and a program for implementing the above-mentioned control method are stored, and CPU (central processing unit) which executes an operation based on the program from vehicle position information and map information. Device) 18 and the calculated steering angle command value αre
A D / A converter 20 for analog-converting and outputting a steering angle output αout calculated from f and a steering angle measurement / detection value α
It has and.

FIG. 9 is a device configuration diagram of the control device when the relative position from the target trajectory can be detected. As shown in FIG. 9, the control device 22 inputs the relative position (lateral deviation amount y, azimuth angle deviation amount ψ) from the target track of the vehicle and the curvature (curvature radius R) of the target track to the signal interface 24.
And an A / D converter 26 which receives and digitally converts the actual steering angle value α, and calculates a steering angle according to a relative position from the target trajectory and a curvature of the target trajectory and a deviation amount and a change in the curvature. It is calculated from a memory 28 in which a program to be stored is stored, a CPU (central processing unit) 30 that executes a calculation based on the program, a calculated steering angle command value αref, and a measured / detected value α of the steering angle. The steering angle output αout is converted into an analog signal and output.

FIG. 10 shows a configuration for carrying out a control method for setting the steering angle to a desired value, that is, a method for calculating the steering angle output. Here, the steering angle command value αref is a value calculated by the block diagram of FIG. 3, the steering angle α is a value of an actual steering angle measured and detected by an encoder, and the steering angle output αout is steering. It is the output to the actuator to move. The compensator 34 is realized by a PID controller or the like. These calculations are included in the program of the control device.

[0060]

Since the present invention is configured as described above, it has the following effects. (1) It is possible to accurately follow a target trajectory even for an arbitrary target trajectory whose curvature changes. (2) The traveling speed of the vehicle is arbitrary (no control is required), and the control method of the present invention is applicable regardless of the traveling speed of the vehicle. (3) By the proportional / integral control, the steady deviation of the position from the target trajectory can be removed, and the accuracy of the traveling control is further improved. (4) Even if there is no map information of the target trajectory, the control can be performed if the relative lateral deviation amount and the azimuth deviation amount can be detected and the curvature of the target trajectory can be estimated or detected. (5) When the curvature of the target trajectory is sufficiently small,
It is possible to control if only the lateral shift amount and the azimuth angle shift amount relative to the target trajectory can be detected.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a relationship between a target trajectory and a traveling trajectory in an absolute coordinate system in a control method of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a target trajectory and a traveling trajectory after the coordinate system is converted (vehicle coordinate system) in the control method of the present invention.

FIG. 3 is a block diagram showing a control system in the present invention.

FIG. 4 is an explanatory diagram showing a relationship between an absolute coordinate system and a reference point reference coordinate system.

FIG. 5 is an explanatory diagram showing a movement amount of each part during a minute time when traveling on a curve.

FIG. 6 is a graph showing a simulation result in a conventional control system.

FIG. 7 is a graph showing a simulation result in the control system of the present invention.

FIG. 8 is a device configuration diagram of a control device having a map of a target trajectory and capable of detecting the position and azimuth angle of a vehicle in real time in a device for implementing the control method of the present invention.

FIG. 9 is a device configuration diagram of a control device when a relative position can be detected in a device that implements a control method of the present invention.

FIG. 10 is a block diagram showing a steering angle calculation means in an apparatus for carrying out the control method of the present invention.

FIG. 11 is an explanatory diagram showing a relationship between a target trajectory and a traveling trajectory in the conventional control method.

FIG. 12 is a block diagram showing a control system in a conventional control method.

[Explanation of symbols]

10, 22 Control device 12, 24 signal interface 14,26 A / D converter 16, 28 memory 18, 30 CPU (Central processing unit) 20, 32 D / A converter 34 Compensator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-110712 (JP, A) JP-A-5-216535 (JP, A) JP-A-2-105904 (JP, A) JP-A-4- 294405 (JP, A) JP 8-137549 (JP, A) JP 11-327641 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G05D 1/02

Claims (6)

(57) [Claims] 1. A method for controlling automatic traveling of a vehicle, wherein a reference point is set on a target trajectory such that the vehicle position is in a direction normal to the target trajectory with respect to an arbitrary target trajectory whose curvature changes. provided, the traveling direction and the normal direction of the target track with respect to the reference point coordinate system from the absolute coordinate system of the vehicle position perpendicular
While converting to the relative coordinate system, the relative lateral deviation and azimuth deviation from the target trajectory are calculated, and the proportional lateral control provides a feedback operation amount according to the relative lateral deviation and azimuth deviation. , Curvature of target trajectory and target trajectory
A steering control method for a vehicle system, characterized in that the steering angle is determined by a feedforward operation amount corresponding to the relative lateral deviation amount. 2. The traveling control method for a vehicle system according to claim 1, wherein the steering angle is determined in consideration of removing the steady deviation of the position from the target trajectory by using proportional / integral control instead of proportional control. . 3. A lateral deviation amount and a relative azimuth deviation amount directly with respect to the target trajectory are detected, and the curvature of the target trajectory is detected or estimated, and the state quantities used for control are detected. The vehicle system travel control method according to claim 1, wherein the steering angle is determined by inputting a value. 4. The vehicle base where the curvature of the target track is the vehicle
4. The traveling control method for a vehicle system according to claim 3, wherein only a relative lateral deviation amount and an azimuth deviation amount from a target trajectory are detected and controlled when the value is sufficiently smaller than the target trajectory. 5. An input means for inputting measurement / detection values of a vehicle position and azimuth, an A / D conversion means for inputting measurement / detection values of a steering angle, and a digital conversion, and a map of a target trajectory. information, and the vehicle position to the target orbit is a reference point provided such that the normal direction of the target track, coordinate system of the target trajectory with respect to the reference point from the absolute coordinate system of the vehicle position
Convert to a relative coordinate system in which the traveling direction and the normal direction are orthogonal , calculate the relative lateral deviation and azimuth deviation from the target trajectory, and perform relative control by proportional control or proportional / integral control.
Feedback operation amount according to the amount of lateral deviation and azimuth deviation, the curvature of the target trajectory, and the phase from the target trajectory
Stored by the feed-forward operation amount according to pairwise lateral displacement amount, a memory means having a program for calculating the steering angle, the vehicle position information and memory means the position and the azimuth angle of the vehicle is measured and detected Calculation means for executing a calculation based on a program from the map information of the calculated target trajectory, and a steering angle output calculated from the calculated steering angle command value and the measurement / detection value of the steering angle are analog-converted and output. D /
A traveling control device for a vehicle system, comprising: A conversion means. 6. An input means for inputting a measured / detected value of a relative lateral deviation amount and an azimuth deviation amount from a target trajectory of a vehicle, and a detected value or an estimated value of a curvature of the target trajectory, and a steering angle measurement. - an a / D converting means for detecting values are entered digitally converted, relative by the relative lateral shift amount and the relative azimuthal offset amount or et proportional control or proportional-integral control of the target trajectory
The feedback operation amount according to the lateral deviation amount and the azimuth deviation amount, the curvature of the target trajectory, and the relative from the target trajectory
The Do feedforward manipulated variable corresponding to the lateral shift amount, a memory means having a program for calculating the steering angle, the deviation amount moderate relative lateral shift amount and the azimuth angle of the target trajectory
And a calculation means for executing a calculation based on the curvature of the target trajectory based on a program, and a steering angle output calculated from the calculated steering angle command value and the measured / detected steering angle D / D which outputs the converted analog value.
A traveling control device for a vehicle system, comprising: A conversion means.