JP2002215239A - Method and device for controlling travel of vehicle system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a vehicle such as a general vehicle and a service vehicle having two or more wheels to accurately follow a target track at the time of automatic traveling of the vehicle without generating a lateral deviation or an azimuth deviation. SOLUTION: In a method for controlling the automatic traveling of a vehicle, a reference point is formed on a target route of which curvature is changed so that the position of the vehicle is turned to the normal direction of the target route, a coordinate system is transformed from the absolute coordinate system of the vehicle position into a relative coordinate system based on the reference point, the relative lateral deviation and azimuth deviation from the target route are calculated or measured, and a steering angle is determined by a feedback manipulated variable corresponding to the deviation value and a feedforward manipulated variable corresponding to the curvature and lateral deviation of the target route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic traveling of a vehicle such as a general vehicle or a work vehicle requiring two or more wheels.
The present invention relates to a control method and a control device in a case where a vehicle travels while following a predetermined target trajectory accurately without causing lateral displacement or azimuth displacement.

[0002]

2. Description of the Related Art When a target work is automatically performed by a vehicle such as a general vehicle or a work vehicle that requires two or more wheels, it is necessary to cause the vehicle itself to automatically follow a predetermined target trajectory. In this case, the target trajectory may include not only a straight trajectory but also a curve in which various curvatures are mixed. It is not possible to respond to such a target trajectory simply by feeding back the lateral and azimuth deviations in a fixed coordinate system.Therefore, a control method that can follow an arbitrary trajectory is needed. Become.

As a conventional control method, for example,
"Vehicle route following control and movement planning using nonlinear control theory-garage entry control using switching" (Mitsumi Mihira et al.,
Transactions of the Society of System Control Information, Vol. 6, No. 1,
pp. 37-47, 1993). The relationship between the target trajectory and the running trajectory in this control method is as shown in FIG. 11. When a control system is constructed based on this, a control system block diagram as shown in FIG. 12 is obtained.

[0004]

However, the above-described 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 a target trajectory with a variety of curvatures, observe the lateral and azimuth deviations from the target trajectory and the curvature of the target trajectory, and give an operation amount (steering angle) according to the deviation and the curvature. However, as described above, it is not possible to cope with such a target trajectory simply by feeding back the lateral deviation and the azimuth deviation.

SUMMARY OF THE INVENTION 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 trajectory in a vehicle such as a general vehicle or a work vehicle requiring two or more wheels. To provide a vehicle-based travel control method and apparatus that can accurately follow a target trajectory including a curve having various curvatures by introducing a coordinate transformation and the like in consideration of the above. It is in.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method for controlling the running of a vehicle system, the method comprising the steps of: In contrast, a reference point is provided on the target trajectory so that the vehicle position is in the normal direction of the target trajectory, and the coordinate system is relative to the coordinate system from the absolute coordinate system of the vehicle position with respect to the reference point. Converts to coordinate system, calculates relative lateral deviation and azimuth deviation from target trajectory, and feeds back according to the amount of feedback operation and the amount of target trajectory curvature and lateral deviation by proportional control. The steering angle is determined by a forward operation amount. In the above method of the present invention, the steering angle (operating amount) can be determined in consideration of removing the steady-state deviation of the position from the target trajectory by using the proportional / integral control instead of the proportional control. it can.

In the method of the present invention, the amount of lateral displacement and the amount of relative azimuth deviation can be directly detected with respect to the target trajectory, and the curvature of the target trajectory is detected or estimated. If possible, those values can be input to the state quantities used for control, and the steering angle (operation amount) can be determined. Further, when the curvature of the target trajectory is sufficiently small, it is possible to detect and control only the relative lateral deviation amount and the azimuth deviation amount from the target trajectory.

The vehicle-based travel control device according to the present invention includes an input means for inputting measured / detected values of the position and azimuth of the vehicle, and an A / D converter for inputting the measured / detected values of the steering angle and converting them into digital data. D conversion means, map information of the target trajectory, and a reference point provided on the target trajectory so that the vehicle position is in the normal direction of the target trajectory, and the coordinate system for the coordinate system is determined from the absolute coordinate system of the vehicle position. Convert to a relative coordinate system based on the reference point, calculate the relative lateral deviation and azimuth deviation from the target trajectory, and use the proportional control or proportional / integral control to adjust the feedback operation amount according to the deviation amount. A storage means having a program for calculating a steering angle by a feedforward operation amount corresponding to a curvature and a lateral shift amount of a target trajectory; and executing a calculation based on a program from vehicle position information and map information. It is characterized by including arithmetic means, and D / A conversion means for converting the steering angle output calculated from the calculated steering angle command value and the measured and detected steering angle value into an analog signal and outputting the result. (See FIG. 8).

Further, the apparatus according to the present invention comprises input means for inputting a measured / detected value of a relative lateral deviation amount and an azimuth deviation amount of a vehicle from a target track, and a detected value or an estimated value of a curvature of the target track. A / D conversion means for inputting the measured / detected value of the steering angle and converting the value into a digital value; and performing proportional control or proportional control on the basis of the relative lateral displacement from the target trajectory, the azimuth deviation, and the curvature of the target trajectory. A storage means having a program for calculating a steering angle by a feedback operation amount corresponding to a deviation amount by integral control, and a feedforward operation amount corresponding to a curvature and a lateral deviation amount of a target trajectory; A calculating means for executing a calculation based on a program from the relative position and the curvature of the target trajectory; and converting the steering angle output value calculated from the calculated steering angle command value and the measured / detected steering angle value into an analog signal. It is characterized by comprising encompass output to D / A converter (see Fig. 9).

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications. . (1) Travel Control Method In the conventional control method shown in FIG. 11 described above, 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 amount of lateral displacement is taken 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
FIG. 2 shows the relationship between the target trajectory and the traveling locus in the absolute coordinate system, and FIG. 2 shows the relationship between the target trajectory and the traveling locus after the transformation of the coordinate system (vehicle coordinate system). In FIG. 1, a reference point on the target trajectory is determined such that the vehicle position is in the normal direction of the target trajectory. In FIG. 2, the X 'axis represents the component moving distance parallel to the target trajectory of the vehicle, and the Y' axis represents the amount of deviation from the target trajectory in the normal direction of the vehicle system.

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

[0012]

(Equation 1)

The coordinate transformation from the absolute coordinate system of the vehicle position to the reference point reference relative coordinate system is represented by a matrix shown in Expression 2.

[0014]

(Equation 2)

Assuming that x0 = y0 = 0, the following equation (3) is obtained.

[0016]

(Equation 3)

[0017]

(Equation 4)

Here, if the reference point is determined so that the vehicle position is in the normal direction of the target trajectory, the following condition shown in Expression 5 is obtained.

[0019]

(Equation 5)

FIG. 5 shows the amount of movement of each part during a very short time when traveling on a curve. At this time, in order to set the vehicle coordinate system to a desired coordinate system, it is necessary to satisfy a condition shown in Expression 6, and when considering a change in a short time dt, Expression A6 shown in Expression 6 becomes Expression 7 Expression 7, that is, Expression A7 shown in Expression 8.

[0021]

(Equation 6)

[0022]

(Equation 7)

[0023]

(Equation 8)

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

[0025]

(Equation 9)

If the X 'axis is completely coincident with the traveling direction of the target trajectory, it becomes difficult to linearize the motion of the vehicle.
Here, the actual traveling direction of the vehicle is set to the X 'axis. This is because Expression A8 shown in Expression 9 becomes Expression 10 and does not become Expression 11.

[0027]

(Equation 10)

[0028]

[Equation 11]

Further, from the relationship shown in FIG. 5, Equation 12 is obtained. If dφ is sufficiently small, ta
Since ndφ = dφ, Equation 13 is obtained.

[0030]

(Equation 12)

[0031]

(Equation 13)

Also, dydφ is sufficiently small, and dydφ =
Assuming 0, Equation 14 is obtained. Here, the minute time d
Considering the change at t, the expression shown in Expression 14 becomes the expression shown in Expression 15, that is, Expression A9 shown in Expression 16.

[0033]

[Equation 14]

[0034]

(Equation 15)

[0035]

(Equation 16)

Under 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 nonlinear system shown in Expression A10 of Expression 17.

[0039]

(Equation 18)

Here, if {1 = y, {2 = tan},

[0041]

[Equation 19]

From this, equation (20), which is a linearized system, is obtained.

[0043]

(Equation 20)

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

[0045]

(Equation 21)

At this time, the steering angle α is calculated by the following equation (22).
From Equation 14, Expression A15 shown in Equation 23 is obtained.

[0047]

(Equation 22)

[0048]

(Equation 23)

Control method 2 (proportional + integral control) When control is performed by proportional + integral control, the manipulated variable is defined as in the following equation 24, and a control system is constructed.
Here, yr is a target deviation amount from the X ′ axis, which is 0 here.

[0050]

(Equation 24)

At this time, the steering angle α is calculated by the following equation (25).
Expression 16 is obtained from Expression 16 as shown in Expression 26.

[0052]

(Equation 25)

[0053]

(Equation 26)

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

(3) Method of Detecting Deviations (Relative Lateral Displacement, Relative Azimuth) When a map of the target trajectory is provided and the position and azimuth of the vehicle can be detected in real time. Information on the X-direction displacement of the vehicle, the Y-direction displacement of the vehicle, and the azimuth angle θ of the vehicle in the coordinate system can be measured, and the X-direction displacement of the reference point in the absolute coordinate system, the Y-direction displacement of the reference point, and the target at the reference point Since the azimuth 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.

In the case where the relative position can be detected, the control method according to the present invention calculates a relative shift amount from the map of the target trajectory in the absolute coordinate system and the position / azimuth of the vehicle, and sets the shift amount to zero. However, if the relative lateral deviation y and the relative azimuth deviation ψ can be directly detected with respect to the target trajectory and the curvature of the target trajectory can be estimated or detected, the state used for the control is determined. You can enter those values for the quantity. Then, when the curvature of the target trajectory is small, that is, the radius of curvature R is large, and L / L in Expression A15 (for proportional control) shown in Expression 23 and Expression A17 (for proportional + integral control) shown in Expression 26 are used. (R
When the value of −y) can be neglected sufficiently, the control can be performed only by directly detecting the lateral displacement amount y and the relative azimuth displacement amount ψ 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 the 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
The signal interface 12 for inputting the position (displacement in the X and Y directions) and the azimuth angle θ of the vehicle measured and detected as the vehicle position information, and the value α of the actual steering angle are input and digitally converted. An A / D converter 14, a memory 16 storing map information of a target trajectory and a program for implementing the above-described control method, and a CPU (Central Processing Unit) for executing calculations based on programs from vehicle position information and map information Device) 18 and the calculated steering angle command value αre
D / A converter 20 that converts the steering angle output αout calculated from f and the measured / detected value α of the steering angle into an analog signal and outputs it.
And

FIG. 9 is a block 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 has a signal interface 24 to which a relative position (lateral displacement y, azimuth displacement の) of the vehicle from a target track and a curvature (radius of curvature R) of the target track are input.
And an A / D converter 26 to which the actual steering angle value α is input and converted into a digital signal, and a steering angle corresponding to a deviation amount and a change in curvature from the relative position from the target trajectory and the curvature of the target trajectory are calculated. Memory 28 in which a program to be executed is stored, a CPU (central processing unit) 30 for executing an operation based on the program, and a calculated steering angle command value αref and a measured and detected steering angle value α. A D / A converter 32 for converting the steering angle output αout into an analog signal and outputting the analog output signal.

FIG. 10 shows a configuration for implementing 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 above-described block diagram of FIG. 3, the steering angle α is a value of an actual steering angle measured and detected by an encoder or the like, and the steering angle output αout is a steering angle output αout. 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]

As described above, the present invention has the following effects. (1) It is possible to accurately follow the target trajectory even for an arbitrary target trajectory whose curvature changes. (2) The speed in the traveling direction of the vehicle is arbitrary (no need to control), 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-state 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 and the azimuth deviation can be detected and the curvature of the target trajectory can be estimated or detected. (5) If the curvature of the target trajectory is sufficiently small,
Control can be performed if only the relative lateral deviation amount and the azimuth deviation amount from the target trajectory can be detected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a target trajectory and a running 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 locus after a coordinate system is transformed (vehicle coordinate system) in the control method of the present invention.

FIG. 3 is a block diagram showing a control system according to 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 unit in a short time during a curve running.

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 that has a map of a target trajectory and can detect a position and an azimuth of a vehicle in real time in a device that implements the control method of the present invention.

FIG. 9 is a device configuration diagram of a control device in a case where a relative position can be detected in a device for implementing the control method of the present invention.

FIG. 10 is a block diagram showing a steering angle calculating means in the device for implementing the control method of the present invention.

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

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

[Explanation of symbols]

 10, 22 controller 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

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Murai 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Akashi Plant F-term (reference) 3D032 CC20 DA03 DA87 DC08 DD18 EB04 EC35 5H301 AA01 CC06 FF08 FF11 HH01 HH02 HH05

Claims (6)

[Claims] In a method for controlling automatic traveling of a vehicle, a reference point is set on an arbitrary target trajectory whose curvature changes so that the vehicle position is in the normal direction of the target trajectory. For the coordinate system, the coordinate system is converted from the absolute coordinate system of the vehicle position to the relative coordinate system based on the reference point, and the relative lateral deviation and the azimuth deviation from the target trajectory are calculated, A driving control method for a vehicle system, wherein a steering angle is determined by a feedback operation amount corresponding to a deviation amount by proportional control and a feedforward operation amount according to a curvature and a lateral deviation amount of a target trajectory. 2. The vehicle running control method according to claim 1, wherein the steering angle is determined in consideration of removing a steady-state deviation of a position from a target trajectory by using proportional / integral control instead of proportional control. . 3. The method according to claim 1, further comprising: detecting a relative lateral displacement and a relative azimuth deviation with respect to the target trajectory; detecting or estimating a curvature of the target trajectory; 3. The traveling control method for a vehicle system according to claim 1, wherein a steering angle is determined by inputting a value. 4. The running control method for a vehicle system according to claim 3, wherein when the curvature of the target trajectory is sufficiently small, only a relative lateral deviation amount and an azimuth deviation amount from the target trajectory are detected and controlled. 5. An input means for inputting measurement / detection values of the position and azimuth of the vehicle, A / D conversion means for inputting measurement / detection values of the steering angle and converting them into digital, and a map of a target trajectory. Information, and a reference point is provided on the target track so that the vehicle position is in the normal direction of the target track, and the coordinate system is relative to the coordinate system from the absolute coordinate system of the vehicle position with respect to the reference point. Calculate the relative lateral deviation and azimuth deviation from the target trajectory, and calculate the feedback operation amount according to the deviation amount by proportional control or proportional / integral control, and the curvature and lateral deviation amount of the target trajectory. Storage means having a program for calculating a steering angle based on a corresponding feedforward operation amount; calculating means for performing a calculation based on a program from vehicle position information and map information; and calculated steering Command value and the steering angle output calculated from the measurement and the detected value of the steering angle and outputs the analog conversion D /
A vehicle-based travel control device comprising: A conversion means. 6. Input means for inputting measurement / detection values of a relative lateral deviation amount and a deviation amount of an azimuth angle of a vehicle from a target track and a detection value or an estimated value of a curvature of the target track, and measurement of a steering angle. A / D conversion means for inputting the detected value and converting the digital value into digital data, and the relative deviation from the target trajectory, the deviation of the azimuth and the curvature of the target trajectory are converted to the deviation by proportional control or proportional / integral control. Storage means having a program for calculating a steering angle based on a feedback-based operation amount corresponding to the target trajectory and a feedforward operation amount corresponding to a curvature and a lateral shift amount of the target trajectory; and a relative position from the target trajectory and a target trajectory. Calculating means for executing a calculation based on a program from the curvature; and a D / for converting the steering angle output calculated from the calculated steering angle command value and the measured and detected steering angle value into an analog signal and outputting the converted signal.
A vehicle-based travel control device comprising: A conversion means.