JPWO2014054697A1 - Motor motion control method, motor motion control apparatus and motor vehicle - Google Patents

Abstract

The object is to obtain vehicle characteristics that can realize stable cornering during turning. In the driving control method of the automobile (101), the relationship between the steering angle of the steering wheel (103a) and the roll angle of the vehicle body (111) can be changed by the speed of the automobile (101). This automobile driving control method is particularly applied to personal mobility having at least two front wheels and one or more rear wheels. Further, in order to expand the application range of the vehicle characteristics for realizing stable cornering at the time of turning, the relationship between the roll angle of the vehicle body (111) and the roll angle of the wheels (110) is changed, and the automobile (101) Adjusts the canvas stiffness of the wheel when turning.

Description

  The present invention relates to a motor vehicle motion control method, a motor vehicle motion control device, and a motor vehicle in which the steering ratio is variable according to the vehicle speed. This application claims priority on the basis of Japanese Patent Application No. 2012-220722 filed on October 2, 2012 in Japan, and is incorporated herein by reference. Is done.

  The number of registered automobiles in Japan exceeded 79 million at the stage of April 2012, and passenger cars accounted for about 74%, and private cars accounted for 99.5%. Over. In this way, passenger cars are expected to continue to grow as an important means of transportation for the public. On the other hand, when attention is paid to the number of passengers per vehicle as the usage status of these passenger cars, the number of passenger cars continues to decrease from about 1.7 in 1989, and is now around 1.3. This is also related to the decrease in the number of members per household. In 1975, the number of members with one or two members was 30%. The number of households consisting of 1 to 2 people accounted for about 25%, and about half of all households are expected to show an increasing trend in the future. In particular, the number of nuclear family households excluding this one-person household is less than 60% of the total, and the total of the single household and nuclear family households account for about 85% of the total number of households. As described above, when the number of members per household decreases and the number of passengers per vehicle decreases, the importance of personal mobility for personal use increases (see, for example, Patent Document 1). ). Paying particular attention to the penetration rate of light cars that are light and small, it is about 1/3, which is about 32% of all passenger cars.

  When planning personal mobility from the viewpoint of road occupancy, it can be seen from the size of the vehicle and the projected area from above.

  FIG. 30 shows the relationship between the total length and the projected area for passenger cars and motorcycles currently on the market. In addition, it calculated | required in the projection area full length x full width. From FIG. 30, it can be seen that the total length of a vehicle that is commercially available including a two-wheeled vehicle and the projected area are highly correlated. Further, looking at vehicles that are currently classified as personal mobility, they can be divided into single-passenger width vehicles and double-passenger width vehicles. Therefore, these are classified as PM1 and PM2. Here, considering the road occupancy rate, PM1 vehicles will be treated. In the case of PM1, the width is narrower than the total length, and considering the above results by a regression equation, the width is about 1.2 m for a vehicle having a total length of about 2.5 m. For this reason, when considering the stability at the time of turning, it is considered that a vehicle having a movement form such as a two-wheeled vehicle that turns with a large roll of the vehicle body is effective. In such a vehicle, the centripetal force is a function of the canvas last and cornering force, so how to use them is important.

  Furthermore, in personal mobility as described above, understeer characteristics must be provided in order to ensure stability. For this reason, all commercially available vehicles have weak understeer characteristics. However, in recent years, in personal mobility, it is possible to freely set the steer characteristic and the side slip characteristic while maintaining stability. It is hoped that it can be built.

JP 2004-359232 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an automobile motion control method, an automobile motion control apparatus, and an automobile in which the steering ratio is variable according to the vehicle speed.

  The vehicle motion control method according to the present invention speeds up the steering ratio, which is the ratio of the roll angle and the steering wheel angle of the vehicle body that can control the roll angle when controlling the motion of a vehicle having three or more wheels. It is specified as a function of and varies according to the vehicle speed.

  The vehicle motion control apparatus according to the present invention is capable of controlling at least a variable part for controlling a roll angle of a vehicle body of the vehicle and a roll angle control when performing a motion control when turning a vehicle having three or more wheels. A controller that defines a steering ratio, which is a ratio between the roll angle and the steering wheel angle of the vehicle body, as a function of speed and outputs the steering ratio according to the vehicle speed of the automobile to the variable unit.

  An automobile according to the present invention includes three or more wheels, a vehicle body, and the above-described automobile motion control device.

  In the present invention, the steering ratio, which is the ratio of the roll angle and the steering wheel angle of the vehicle body that can control the roll angle, is defined as a function of speed with three or more wheels, and the steer characteristic and the side slip characteristic are changed by varying the vehicle speed. It can be set freely. Therefore, the present invention can be constructed from a sports car to a family use in a single vehicle by switching the steering ratio according to the vehicle speed.

1 is a block diagram showing an automobile to which a motion control device according to an embodiment of the present invention is applied. It is the perspective view which showed a mode that the motion of the four-wheel vehicle was replaced with the two-wheel model. It is the conceptual diagram which showed the form of roll control, (A) shows lean out, (B) shows lean with, (C) shows lean in. It is the conceptual diagram which showed the coordinate system of vehicle motion. It is the side view which showed the vehicle body dimension. It is the graph which showed the root locus of personal mobility. It is the conceptual diagram which showed the geometric turning characteristic. It is the conceptual diagram which showed the steady circular turning characteristic only for canvas last with centripetal force. It is the conceptual diagram which showed the steady circular turning characteristic in case canvas rust is smaller than the required centripetal force. It is the conceptual diagram which showed the steady circle turning characteristic in case canvas last is larger than the required centripetal force. It is the conceptual diagram which showed the relationship between centrifugal force and gravity. It is the graph which showed the steering ratio which is ratio of a roll angle and a steering angle. It is the figure which showed the steer characteristic. It is the figure which showed the side slip characteristic. It is a perspective view which shows schematic structure of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the block diagram which showed the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the analysis result of the influence of the stability factor with respect to the steering ratio and speed change of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the analysis result of the influence of the stability factor with respect to the change of the vehicle body lean angle of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the analysis result of the influence of the side slip characteristic with respect to the change of the vehicle body lean angle of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the block diagram which showed the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the analysis result of the friction coefficient of the tire and road surface of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the interference result of the longitudinal force and cornering force by the tire model of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the figure which showed the model which unified the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention to the coordinate system. (A) And (B) is the figure which showed the dimension of each part of the model which unified the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention shown in FIG. 23 to the coordinate system. It is the figure which showed typically the state of the vehicle in the turning of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. (A) thru | or (E) is the figure which showed the response result with respect to the speed change of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. (A) thru | or (E) are the figures which showed the response result with respect to the target roll angle change of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. (A) thru | or (E) is the figure which showed the response result with respect to the steering ratio change of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. (A) thru | or (E) is the figure which showed the response result with respect to the additional steering change of the motor vehicle which applied the motion control apparatus which concerns on other one Embodiment of this invention. It is the graph which showed the relationship between a full length and a projection area about the passenger car and two-wheeled vehicle currently marketed.

(First embodiment)
Hereinafter, an automobile motion control method, an automobile motion control apparatus, and an automobile to which an embodiment of the present invention is applied will be described in detail with reference to the drawings. In addition, this invention is not limited to the following examples, In the range which does not deviate from the summary of this invention, it can change arbitrarily. Furthermore, the first embodiment of the present invention will be described in the following order.
1.1. Basic configuration of an automobile to which a motion control device according to an embodiment of the present invention is applied 1.2. Basic configuration of a vehicle having a large roll angle 1.3. Theory of vehicle motion 1.3.1 Coordinate system and tire force 1.3.2 Equation of motion 1.3.3 Stability of system 1.3.4 Steady circular turning characteristics 1.3.5 Reference canvas last Characteristics 1.3.6 Steering characteristics and sideslip characteristics 1.4. Examination of tire motion characteristics in consideration of tire characteristics 1.4.1 Vehicle motion characteristic index based on tire characteristics 1.4.2 Steering ratio investigation 1.4.3 Steering characteristics and side slip characteristics with respect to steering indices 1.5. Conclusion

1.1. 1. Basic configuration of an automobile to which a motion control device according to an embodiment of the present invention is applied A vehicle 101 to which an automobile motion control device 120 according to an embodiment of the present invention is applied is a vehicle capable of realizing stable cornering during turning. In order to obtain characteristics, the relationship between the steering angle of the steering wheel and the roll angle of the vehicle body can be changed by the speed of the automobile 101. The automobile 101 of the present embodiment is personal mobility having, for example, three or more wheels (tires) 110 and a vehicle body 111 capable of roll angle control that rolls and turns like a two-wheeled vehicle. Further, as shown in FIG. 1, the automobile 101 detects a vehicle speed by a roll angle detection unit 112 that detects the roll angle of the vehicle body 111, a handle angle detection unit 113 that detects the handle angle of the handle 113 a, and the vehicle speed. The vehicle speed detection unit 114, the variable unit 115 that controls the roll angle of the vehicle body 111, the steering ratio that is the ratio of the roll angle and the steering wheel angle of the vehicle body is defined as a function of speed, and the steering ratio according to the vehicle speed is variable unit 115. And a controller 116 for outputting to the controller.

  The roll angle detection unit 112, the handle angle detection unit 113, and the vehicle speed detection unit 114 are configured using, for example, a well-known sensor, and output detected data to the controller 116. For example, the variable portion 115 can change the height of one and the other of the front wheels and / or the height of one and the other of the rear wheels by changing the length of the upper arm of the tire with a hydraulic piston or the like. The roll angle of the vehicle body 111 is controlled. The controller 116 is constituted by, for example, a microcomputer, and defines a steering ratio, which is a ratio of the roll angle of the vehicle body and the steering wheel angle, as a function of speed in accordance with a control program stored therein, and according to the vehicle speed. The steering ratio is output to the variable unit 115. In FIG. 1, four wheels (tires) 110 are provided. However, the present invention is not limited to this, and the number of wheels of the automobile 101 in the present embodiment is at least two front wheels and rear wheels. If there are one or more wheels, the number may be three, or four or more.

  In the automobile 101 to which the embodiment of the present invention having the above-described configuration is applied, the controller 116 detects the roll angle of the vehicle body 111 detected by the roll angle detection unit 112 and the handle angle detected by the handle angle detection unit 113. The steering ratio, which is the ratio of the two, is defined as a function of speed, and the steering ratio corresponding to the vehicle speed is output to the variable unit 115. Therefore, the driver can freely set the steer characteristic and the side slip characteristic with an operation unit (not shown), and a single vehicle can be constructed from a sports car to a family use. In addition, in the motion control method of the automobile 101 of the present embodiment, the relationship between the steering angle of the handle 113a and the roll angle of the vehicle body 111 can be changed according to the speed of the automobile 101 when the automobile 1 turns, so The characteristics can be freely set, and in particular, the vehicle body 111 can be smaller and lighter than a normal vehicle, and stable vehicle characteristics can be obtained during slender personal mobility turning. Note that the motion control device 120 and the motion control method for the automobile 101 according to an embodiment of the present invention were created by the present inventor through kinematic verification in accordance with the following description.

1.2. Basic configuration of a vehicle having a large roll angle The PM1 vehicle has a two-input system of a roll angle (φ) control and a handle angle (δ) control. When these are controlled independently, it is necessary for a general driver to control them independently. Therefore, if the control of the accelerator and the brake is loaded on this, the maneuvering itself becomes very complicated. Therefore, the number of inputs is limited by defining and simplifying these relationships. Therefore, the present invention assumes the following relationship. Here, k is defined as a steering ratio, and this steering ratio is a function of speed. This relationship can be realized by moving the suspension mounting position up and down.

  In addition, when performing roll control, it is necessary to consider three forms that are normally used in a motorcycle: lean in, lean with, and lean out. Therefore, first, in order to simplify the motion of the four-wheel vehicle including the roll, the two-wheel model is replaced as shown in FIG.

Next, the form of roll control is defined as shown in FIGS. 3A to 3C from the relationship between the vehicle body roll angle and the tire camber angle. Here, φ represents a mechanical roll angle, and φ _t represents a tire camber angle. By effectively setting this relationship, the vehicle characteristics can be greatly changed.

1.3. Theory of vehicle motion 1.3.1 Coordinate system and tire force In the case of vehicle construction with the main centripetal force represented by a canvas last represented by a two-wheeled vehicle, it is easy to understand the coordinate system that expresses the motion using the SAE coordinate system. When the steering angle is positive, the cornering force and the yaw rate are positive, the camber angle is positive from the relationship of the expression (1), and the canvas last is also positive. Further, since the vehicle body rolls greatly, the origin of coordinates is set at the center A of the rear tire contact point as shown in FIG. Also, the width of the tire is not taken into consideration because of the simplification of the formula. The tire force is considered as a linear model and is defined by the following equation.

Here, K _Ci : canvas stiffness, K _Si : cornering stiffness, α _i : tire slip angle. Here, i indicates a tire number, i = A is a rear wheel, and i = B is a front wheel.

1.3.2 Equation of motion First, the speed, acceleration, etc. at point A are shown. The basic dimensions are shown in FIG. In this case, unit vectors representing the direction of the inertial coordinate system (O- _XYZ ) are i, j, and k. Also, the dynamic coordinate system _{A -xa, yA,} a unit vector representing the direction of _{zA e xA,} e _yA, and _{e zA.} Using these, the speed at point A is given by the following equation.

  The position vector of the center of gravity point viewed from point A is described below.

  Therefore, the linear acceleration of the center of gravity is given by the following equation.

  Similarly, the speed at point B is given by:

  Therefore, the side slip angle at points A and B is given by the following equation.

Here, constant speed traveling is considered, and the equation of motion considers the balance around the y _A direction and the z _A axis. Therefore, it is given by the following equation.

  Substituting (1) and (2) into these formulas

1.3.3 System stability Next, the stability of this vehicle system will be examined. Since this vehicle adopts a format in which the steering angle and the roll angle are defined by the steering angle, the roll angle is included in the steering angle as an input. For this reason, the characteristic equation is the same as that of a normal four-wheeled vehicle. Then, it analyzes using the specification shown in Table 1, and shows the root locus with respect to speed in FIG. In FIG. 6, the speed is shown up to 30 m / s. However, in this specification, it is stable in all regions, and it can be seen that directional stability is ensured.

1.3.4 Steady circle turning characteristics The vehicle stability is ensured as described above, and it has been confirmed that the vehicle system is valid. However, when considering the basic characteristics of the vehicle, the steady gain at the normal traveling speed is an important factor. First, the concept of how the characteristics change due to steady circular turning will be described.

  First, consider extremely low-speed turning (geometric turning characteristics). In this case, the roll angle is set to 0 assuming that the speed is 0. Thus, the relationship between the steering angle and the turning radius is shown in FIG.

  Therefore, this relationship is expressed by the following equation.

  In this turning, since each tire does not require centripetal force, it proceeds in the wheel center direction with a side slip angle of 0. On the other hand, when the centripetal force is only canvas last, each tire does not have a side slip angle, and therefore, as shown in FIG. 7, it is shown in FIG. Therefore, the turning center is located on the rear wheel shaft extension line.

  If this canvas last is less than the required centripetal force, it must be compensated with a cornering force. For this reason, the side slip angle of each tire is negative as shown in FIG. Therefore, the turning center is located in front of the rear wheel shaft. For this reason, the attitude angle of the vehicle is inward, and the rear wheels protrude outward.

  Further, when the centripetal force required by the canvas last is larger, as shown in FIG. 10, it is necessary to generate a cornering force on the negative side from the balance of steady circular turning. That is, since the side slip angle is positive, the turning center is located behind the rear wheel shaft, and the vehicle turns outward. From these relationships, in the case of a vehicle having canvas last as the main centripetal force, the reference is considered to be a state of turning only by canvas last as shown in FIG. Therefore, the standard of the steady circle turning characteristic is a vehicle having such tire characteristics.

1.3.5 Standard Canvas Last Characteristics The vehicle considered here is lean with as described above, and is a four-wheeled vehicle, but in order to set the load equally on the left and right tires, The conditions shown in FIG. 11 are necessary. Therefore, it is necessary to generate a force having the same magnitude as the centrifugal force and the opposite direction by the canvas last generated at the front wheel and the rear wheel, and further, the moment around the center of gravity generated by the longitudinal force must be balanced. Further, the roll angle in this case represents the centripetal acceleration displayed in G as defined by the equation (13). Using this relationship, the reference canvas stiffness is obtained by equation (14).

When this value is applied to the above-mentioned Table 1, the reference canvas stiffness is as follows.
K _CB0 = 1470 N / rad, K _CA0 = 1470 N / rad

1.3.6 Steering characteristics and sideslip characteristics In this section, the steady circular turning characteristics shown in the above section 1.3.4 are considered theoretically. In this case, it is obtained by deleting the acceleration term of the equation (11).

  In general, when considering steady-state characteristics, consider the center of gravity. In particular, the side slip characteristic cannot be calculated because the geometric side slip angle at the reference point A is 0. Therefore, the above equation is replaced with the barycentric point for analysis. Therefore, when the lateral slip angle of the center of gravity is β, this relationship is given by the following equation.

  Therefore, when this is substituted, the following equation is obtained.

First, the relationship between the reference geometric turning radius R ₀ , the steering angle δ ₀ , and the side slip angle β ₀ is shown.

  When the steer characteristic is obtained from the equation (17), the following equation is obtained.

  Here, the stability factor is given by the following equation.

  In this equation, the first term on the right side is the same as the stability factor of a normal four-wheeled vehicle, and the second term is a term peculiar to the vehicle in consideration of the camber angle like PM1.

  Similarly, the side slip characteristic is obtained by the following equation.

  Here, the side slip coefficient is given by the following equation.

  The first term on the right side of the equation represents the side slip coefficient of the four-wheeled vehicle as described above, and the second term represents the influence of the camber angle.

1.4. Examination of kinematic characteristics considering tire characteristics 1.4.1 Vehicle kinematic characteristics index based on tire characteristics From the viewpoint of providing vehicle characteristic information during vehicle design, these examinations are based on the canvas stiffness of the front and rear wheels and the aforementioned reference canvas last. I do. First, when the above-mentioned reference canvas stiffness is substituted into the above equations (20) and (22), both the stability factor and the side slip coefficient become zero. In other words, the centripetal force is all covered by canvas last, so the cornering force is no longer affected and neutral steer. This means that when passing through a circle with the same turning radius, the steering angle and the side slip angle are constant regardless of the speed. Therefore, in the case of the vehicle shown in the present invention, the steering characteristic reference is neutral steering.

  Next, the following two parameters representing the tire characteristic relationship are newly introduced.

ξ represents the relationship between the canvas stiffness of the front wheel and the rear wheel, and κ _A represents the relationship between the actual canvas stiffness and the reference canvas stiffness. Using these, K _C shown in the equation (17) is arranged.

  Similarly, the side slip coefficient expressed by the equation (22) is arranged.

  From these results, the following index is established from the equation (24) for the steer characteristic.

The following characteristics can be defined by this index.
SI <0: The reference US (understeer) is decreased, and the OS (oversteer) characteristic is obtained depending on the value.
SI = 0: The steering characteristic is determined only by the cornering power.
SI> 0: US characteristics are stronger than the standard US.

  Therefore, although the reference vehicle shown in Table 1 is a stable vehicle, the OS characteristic can be realized while maintaining stability by the value of canvas stiffness.

Similarly, in the case of the side slip characteristic, κ _A is an index from the equation (25). The following characteristics can be defined by this index.
κ _A <1: The side slip angle decreases with increasing speed.
κ _A = 1: The side slip angle is always constant regardless of the speed change.
κ _A > 1: The side slip angle increases with increasing speed.

  Therefore, in the case of the vehicle shown in Table 1, when the rear wheel canvas stiffness is 1620 N / rad, the steady side slip angle is always constant regardless of the speed, and when it has a value larger than this, the vehicle body is gradually increased as the turning speed increases. It turns out that it turns to the outside. In this way, in the case of a vehicle having canvas last as the main centripetal force, it is possible to express characteristics that can not be realized with a passenger car due to the relationship of the canvas stiffness of the front and rear wheels and the relationship of the cornering power, which has great potential from the standpoint of characteristic design. I understand that.

1.4.2 Examination of Steering Ratio As given by equation (1), in order to avoid the difficulty of steering the vehicle, the ratio between the roll angle and the steering angle was defined as a function of speed. A study will be made on how to determine the steering ratio k. As the speed increases, the steering angle is determined from equation (19), and the roll angle is determined by centripetal acceleration as shown in equation (13). Therefore, this ratio is affected by the steering characteristic as shown in the following equation.

Here, the specifications shown in Table 1 are examined. FIG. 12 shows a steering ratio with respect to a change in speed and a change in multiplication of κ _A and SI that determines K _c by equation (24). From FIG. 12, when the negative value of this index increases, the steering ratio is greatly affected. Therefore, the setting of the cornering power of the front wheels and the rear wheels, which are the basis of these analyses, is greatly affected. Normally, the cornering power of the front wheels is greatly affected by the rigidity of the steering system, but if this rigidity is low, the negative absolute value of this index becomes large, which makes it difficult to design the steering ratio. It is necessary to ensure the rigidity.

1.4.3 Steer characteristics and side slip characteristics with respect to the steering index Next, the effects of the above-described indices SI and κ _A on the steer characteristics and the side slip characteristics will be examined. FIG. 13 shows the analysis result of the steer characteristic, and FIG. 14 shows the analysis result of the side slip characteristic. FIG. 13 shows that the steer characteristic can be expressed from the strong US characteristic to the strong OS characteristic in this range. In this sense, it can be seen that the characteristics can be greatly changed, particularly by setting the tire. Further, it can be seen from FIG. 14 that by setting κ _{A as} the side slip characteristic, the steady side slip characteristic can be increased and the posture of the vehicle can be changed. From such analysis, it is possible to realize the setting of the motion characteristics of PM1 from a very high sporting characteristic to a calm characteristic for steering for a general driver, which is very high as a new vehicle system. You can see that it has potential.

1.5. CONCLUSION In one embodiment of the present invention, the following conclusion was obtained regarding the basic structure of a new personal mobility that effectively uses the tire canvas last.

  (1) By effectively using the canvas last, it is possible to largely set the characteristics from the US characteristics to the OS characteristics while ensuring the stability of the vehicle system.

  (2) As described above, the normal side slip angle can be set to both the outside and inside of the turn by setting the actual canvas stiffness with respect to the reference canvas stiffness, and the degree of freedom in design can be increased.

(Second Embodiment)
Next, an automobile motion control method, an automobile motion control apparatus, and an automobile to which another embodiment of the present invention is applied will be described in detail with reference to the drawings. The second embodiment of the present invention will be described in the following order.
2.1. Basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied 2.2. Basic configuration of a vehicle having a large roll angle 2.3. Improvement of characteristics by changing the roll angle of the car body 2.3.1 Analysis considering the lean angle of the car body 2.3.2 Effect of the lean angle of the car body on the vehicle characteristics 2.4. Conclusion

2.1. Basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied First, a basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied will be described with reference to the drawings. To do. FIG. 15 is a perspective view showing a schematic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied, and FIG. 16 applies a motion control device according to another embodiment of the present invention. It is a block diagram showing an automobile.

  The motion control device according to the present embodiment is applied to, for example, the automobile 201 called personal mobility, which is a small vehicle (PM1) on which about 1 to 2 people can ride, and is more stable at the time of turning than the first embodiment. The range of application of vehicle characteristics that can achieve cornering is expanded. As shown in FIG. 15, the automobile 201 according to the present embodiment has a vehicle body 211 having a total length of about 2 to 4 m and a width of about 1 to 2 m. (Tire) 210 is provided. In FIG. 15, four wheels 210 are provided, but the number of wheels is not limited to four. That is, the number of wheels may be three or four or more as long as there are at least two or more front wheels and one or more rear wheels.

  In addition, the automobile 201 in the present embodiment is provided with a handle 213a for turning the vehicle and the like, and a lever-shaped operation unit 217 for changing the roll angle of the vehicle body 211 and the wheels 210 with respect to the road surface in the vicinity of the handle 213a. It has been. Note that the operation unit 217 is not limited to a lever shape as shown in FIG. 15, and may be, for example, a device provided with a plurality of buttons and meters, or an operation lever or an operation part of the handle 213 a. It is good also as a structure in which a button is provided integrally.

  In this embodiment, in order to expand the application range of vehicle characteristics that can realize stable cornering during turning, the operation unit 217 changes the relationship between the roll angle of the vehicle body 211 and the roll angle of the wheels 210 to The canvas stiffness of the wheel 210 at the time of turning 201 is adjusted. As shown in FIG. 16, the motion control device 220 of the automobile 201 according to the present embodiment includes a controller 216, a variable unit 215, a handle angle detection unit 213, a roll angle detection unit 212, a vehicle speed detection unit 214, And an operation unit 217. The handle angle detection unit 213, the roll angle detection unit 212, and the vehicle speed detection unit 214 are configured using, for example, known sensors, and the detected handle angle of the handle 213a, roll angles of the vehicle body 211 and the wheels 210, and vehicle speed data. Are detected and output to the controller 216.

  In this embodiment, the variable unit 215 controls the roll angle of the vehicle body 211 so that the relationship between the roll angle of the vehicle body 211 and the roll angle of the wheel 210 can be changed by the operation unit 217. And a wheel roll angle variable unit 219 that controls the roll angle of the wheel 210. That is, the variable section 215 can tilt the vehicle body 211 and the wheels 210 independently from each other with respect to the road surface.

  The vehicle body roll angle variable unit 218 can change the height of one and the other of the front wheels and / or the height of one and the other of the rear wheels by changing the length of the upper arm of the tire with a hydraulic piston or the like, for example. The roll angle of the vehicle body 211 is controlled by making the difference. The wheel roll angle variable section 219 controls the roll angle of the wheel 210 by making it possible to change the angle of the wheel 210 (front wheel, rear wheel) with respect to the road surface with, for example, a suspension or a hydraulic piston.

  Similarly to the first embodiment, the controller 216 is configured by a microcomputer or the like, for example, and in accordance with a control program stored therein, the controller 216 speeds up the steering ratio that is the ratio of the roll angle and the steering wheel angle of the vehicle body 211. The steering ratio corresponding to the vehicle speed is output to the variable unit 215. Further, in the present embodiment, the controller 216 adjusts the roll angle of the vehicle body 211 and the roll angle of the wheel 210 by operating the vehicle body roll angle variable unit 218 and the wheel roll angle variable unit 219 with the operation unit 217. It is possible to make it possible.

  Thus, in the present embodiment, the controller 216 changes the relationship between the roll angle of the vehicle body 211 and the roll angle of the wheel 210 by adjusting the roll angle of the vehicle body 211 and the roll angle of the wheel 210, The canvas stiffness of the wheel 210 when the automobile 201 turns is adjusted. The controller 216 determines the magnitude relationship between the roll angle of the vehicle body 211 and the roll angle of the wheel 210, and the vehicle body roll angle is variable based on the determination result of the determination unit 216a so that the wheel 210 has a desired canvas stiffness. A command unit 216b that commands to adjust the unit 218 and the wheel roll angle variable unit 219.

  In the present embodiment, by providing the controller 216, the relationship between the roll angle of the vehicle body 211 and the wheel 210 can be changed by operating the variable unit 215 with the operation unit 217 via the controller 216 during turning. Specifically, the relationship between the roll angle of the vehicle body 211 and the wheel 210 at the time of turning is tilted toward the vehicle body 211 relative to the wheel 210 to lean the vehicle body 211 to the inside of the turn, and the wheel 210 rather than the vehicle body 211. It is changed so as to be in a lean-out state in which the vehicle body 211 is leaned to the outside of the turn, or a lean with state in which the wheels 210 and the vehicle body 211 have substantially the same inclination. In this way, when the automobile 201 turns, the canvas stiffness of the wheel 210 is adjusted to a desired size by changing the relationship between the roll angle of the vehicle body 211 and the wheel 210. That is, even when the relationship between the roll angles of the vehicle body 211 and the wheels 210 is lean in or lean out, the vehicle characteristics during turning can be stabilized and excellent cornering characteristics can be obtained.

  For example, to make the car 201 have a thrilling sports car type vehicle characteristic, the wheel 210 is tilted more than the vehicle body 211 so that the roll angle is larger, and the canvas stiffness is adjusted to be larger. To do. On the other hand, when it is desired to make the automobile 201 have a family use type vehicle characteristic that is relaxed and stable, the lean angle of the wheel 210 is made small, and the wheel 210 is made to have a smaller roll angle than the vehicle body 211. Move in the standing direction and adjust the canvas stiffness to be smaller.

  As described above, in this embodiment, the vehicle body roll angle variable unit 218 and the wheel roll angle variable unit 219 can be adjusted by the operation unit 217 via the controller 216 so that the wheels 210 have the desired canvas stiffness as described above. . Conventionally, since the canvas stiffness is determined depending on the type of the automobile and the tire (wheel) provided in the automobile, it is necessary to change the tire each time in order to change the vehicle characteristics including the canvas stiffness.

  On the other hand, in the automobile 201 of the present embodiment, the relationship between the roll angle of the vehicle body 211 and the roll angle of the wheels 210 can be freely changed while adjusting the variable unit 215 with the operation unit 217 via the controller 216. For this reason, since it can adjust with the operation part 217 at the time of the driving | running | working of the motor vehicle 201 so that the canvas stiffness of the wheel 210 at the time of the turn of the motor vehicle 201 may become a desired magnitude | size, it can change from a sports car type to a family use type in the single motor vehicle 201. It can be changed to a wide range of vehicle characteristics. Moreover, when designing the automobile 201 according to the present embodiment, the design range of the vehicle is greatly expanded. In particular, the present embodiment is applied to the automobile 201 called personal mobility that is smaller and lighter than an ordinary vehicle and has an elongated vehicle body 211, and therefore has vehicle characteristics that can be flexibly changed by a driver like a motorcycle. However, the vehicle can be used as a highly safe vehicle that ensures stability during turning. That is, the personal mobility applied as the automobile 201 according to the present embodiment is an unexpected accident while the driver can flexibly adjust the roll angle of the vehicle body 211 and the wheel 210 when turning, like a motorcycle, and change the vehicle characteristics. It is possible to ensure safety that the driver is protected from an external impact or the like by the vehicle body 211 when the vehicle collides or falls due to the above. Note that the motion control device 220 and the motion control method of the automobile 201 according to the present embodiment are created by the inventor after kinematically verifying according to the following description.

2.2. Next, a basic configuration of a vehicle having a large roll angle in the automobile according to the present embodiment will be described. Similar to the first embodiment described above, the PM1 vehicle, which is an automobile according to this embodiment, is a four-wheeled vehicle, and the roll angle is determined geometrically by connecting the front and rear left and right wheels with links. Defined as system. Therefore, in this vehicle, a two-input system of a roll angle (φ) and an actual steering angle (δ) is combined with a steering ratio κ (ν) that is a function of the speed ν shown in the equation (27). It was proposed that the driver can perform lateral control with one input. In Equation (27), g is gravitational acceleration, l is a wheel base that is the distance between the front wheel and the rear wheel, and K _δ is a stability factor.

  By combining with such a steering ratio defined by equation (27), the steering characteristic of the vehicle can be made constant with respect to changes in speed. Therefore, when the steering ratio is indicated by using an index based on the relative tire characteristic that determines the steering characteristic defined in the speed and the previous report, it is given as shown in FIG. The specifications of the vehicle used for the analysis are the same as in Table 1 described above.

Here, assuming that the cornering stiffness is Ks, the rear wheel canvas tint is K _CA , and the canvas stiffness that can bear the centripetal force only by the canvas last is K _CA0 , κ _A and SI are given by the above-described equation (23). Here, ξ is given by the aforementioned equation (23) as the ratio of the canvas stiffness of the front and rear wheels.

Further, the restability factor by κ _A and SI is shown in FIG. 13 described above. From this figure, it can be seen that this vehicle has neutral steer when κ _A is 1 and SI is 0, and it is possible to set both oversteer and understeer by appropriately selecting these values. I know that there is. Further, as analyzed in the first embodiment, dynamic stability is ensured in all these states.

Similarly, the gravity center side slip coefficient in this case is shown in FIG. From this figure, slip angle coefficient is found to be defined by the kappa _A. It can be seen that when this value is 0, the side slip coefficient is 0, and the side slip angle is always 0 with respect to the change in the turning speed.

  It can also be seen that the change in SI does not affect the barycenter side slip angle at all. Therefore, it can be seen that the use of these two values can freely set the steer characteristic and the lateral slip characteristic at the time of design. Therefore, the above-described equation (27) is used to analyze the influence of the stability factor on the steering ratio and the speed change, and the analysis result is shown in FIG. Here, the foil base was analyzed as 2 m. It can be seen from FIG. 17 that the specification shows a large understeer characteristic in a portion where the steering ratio is very small. It can also be seen that the stability factor is substantially constant when the steering ratio is 10 or more and 10 m / s or more. In addition, the region where the steering ratio is small is a region where the influence of the steering angle is very large, which means that the effect of preventing rollover due to the large roll angle that the vehicle originally has becomes small.

  Therefore, depending on the initial tire characteristics (relationship between the cornering stiffness of the front and rear wheels and the canvas stiffness), the effect of changing the steering angle ratio is mainly related to the improvement of characteristics such as handling at extremely low speeds. Will do. For this reason, the standard for the tire characteristics is defined by the initial setting conditions of the tire, and this mainly means that the relationship between the steering characteristics and the side slip characteristics can be set relatively freely.

2.3. Next, characteristic improvement due to a change in the roll angle of the vehicle in the vehicle according to the present embodiment will be described. The extent to which the vehicle characteristics can be changed after the design specifications of the vehicle are determined greatly affects the range of use of the vehicle in this relationship. In general, the rider of a motorcycle changes the characteristics of a two-transit vehicle greatly depending on how to ride, but in the automobile according to this embodiment, the vehicle characteristics can be changed greatly by introducing a mechanism equivalent to this. Do this because it is possible.

  The form of roll control is defined as shown in FIGS. 3A to 3C from the relationship between the vehicle body roll angle and the tire camber angle. In general, as shown in FIG. 3 (A), leaning out the vehicle body leaning outward with respect to the roll angle of the tire, and conversely, as shown in FIG. The thing that makes you lean is called lean in. Further, as shown in FIG. 3B, a case where the intermediate tire and the vehicle body have the same roll angle is referred to as lean with. By such a change, the combined center of gravity position is changed to the left and right, and the mechanical roll angle is controlled.

2.3.1 Analysis Considering Lean Angle of Car Body Next, an analysis considering the lean angle of the car body in the automobile according to the present embodiment will be described. Vehicle characteristic analysis is performed assuming that the relationship between the vehicle body roll angle and the tire roll angle shown in FIGS. 3A to 3C can be freely set. Here, the mechanical roll angle is φ, the roll angle of the vehicle is φ _ν , and the change in roll angle due to the vehicle body is φ _b, and this relationship is expressed by the following equation (28).

Since this relationship is handled with a constant characteristic, φ _b is given by the following equation (29) as being proportional to the centripetal acceleration.

Here, the mechanical roll angle is defined by the following equation (30).

  The ratio τ between the vehicle camber angle and the mechanical camber angle is defined by the following equation (31).

  Therefore, when the steering characteristic and the side slip characteristic are derived using these expressions, the following expressions (32) and (33) are obtained, respectively.

Here, the stability factor and the side slip coefficient are given by the following equations (34) and (35).

From this figure, the influence of the vehicle body camber angle is given by τ described above, and these are all given by multiplication with κ _A given by the canvas stiffness ratio. Therefore, the vehicle body camber angle variation represented by C _b is equivalently equal to changing the canvas stiffness of the tire. Therefore, it means that the canvas specification, which is a design specification, can be equivalently changed according to the control conditions. In other words, it means that the design target characteristics can be significantly changed by changing such characteristics.

2.3.2 Influence of vehicle body lean angle on vehicle characteristics Next, the influence of the vehicle body lean angle on the vehicle characteristics according to the present embodiment will be described. The change in the C _b shown in the previous section, 18 and 19 an analysis result as to whether it is possible to what extent changes the steering characteristic and sideslip characteristics. In the figure, η is a value indicating the relationship of the canvas stiffness to the reference canvas stiffness that is a value that can generate centripetal force only by the canvas last, and is given by the following equation (36).

  From this figure, it can be seen that the design specifications of the vehicle can be greatly changed by changing the roll angle of the vehicle body.

2.4. Conclusion In this embodiment, we examined the possibility of significant changes by performing vehicle body roll angle control with respect to the design specifications of a new personal mobility that effectively uses the tire canvas last. I got a conclusion. That is, it is possible to change the equivalent canvas stiffness by analyzing the steering characteristic change due to the change of the steering ratio (vehicle roll angle / steering angle) and changing the relationship between the vehicle roll angle and the tire roll angle. Indicated.

(Third embodiment)
Next, an automobile motion control method, an automobile motion control apparatus, and an automobile to which another embodiment of the present invention is applied will be described in detail with reference to the drawings. The third embodiment of the present invention will be described in the following order.
3.1. Basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied 3.2. Nonlinear vehicle model 3.2.1 Tire characteristics 3.2.2 Acceleration at the center of gravity 3.2.3 Side slip angle of each tire 3.2.4 Equation of motion 3.3. Simulation 3.3.1 Calculation conditions 3.3.2 Effect of speed change 3.3.3 Effect of target roll angle change 3.3.4 Effect of steering ratio change 3.4. Add actual rudder angle at the start of exercise 3.5. Conclusion

3.1. Basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied First, a basic configuration of an automobile to which a motion control device according to another embodiment of the present invention is applied will be described with reference to the drawings. To do. FIG. 20 is a block diagram showing an automobile to which a motion control device according to another embodiment of the present invention is applied.

  Similar to the first and second embodiments, the motion control device according to the present embodiment is applied to, for example, the automobile 301 called personal mobility, and is more stable during turning than the first and second embodiments. The scope of application of characteristics is expanded. In other words, in the first and second embodiments, the present invention is applied to the steady state at the time of turning, but in this embodiment, the automobile 301 is switched from the straight traveling state to the turning state to reach the steady state at the time of turning. It can be applied to the initial turning stage up to and has been studied based on nonlinear characteristics.

  The present embodiment is characterized in that the roll angle is controlled independently for the front wheel 310f and the rear wheel 310r in order to obtain vehicle characteristics that stabilize cornering at the start of turning until reaching a steady state during turning. To do. Specifically, the relationship between the roll angle of the vehicle body 311 on the front wheel 310f side and the roll angle of the wheel 310f is changed within a predetermined time from the start of turning of the automobile 301, and the vehicle body 311 on the rear wheel 310r side after a predetermined time elapses. The relationship between the roll angle and the roll angle of the wheel 310r is changed.

  As shown in FIG. 20, the motion control device 320 of the automobile 301 according to the present embodiment includes a controller 316, a variable unit 315 (315f, 315r), a steering wheel angle detection unit 313, a roll angle detection unit 312, and a vehicle speed. A detection unit 314 and an operation unit 317 are provided. The handle angle detection unit 313, the roll angle detection unit 312, and the vehicle speed detection unit 314 are configured using, for example, known sensors, and the detected handle angle of the handle 313a, roll angles of the vehicle body 311 and the wheel 310, and vehicle speed data. Are detected and output to the controller 316.

  In the present embodiment, similarly to the second embodiment, the variable portion 315 (315f) is provided so that the operation portion 317 can change the relationship between the roll angle of the vehicle body 311 and the roll angle of the wheels 310 (310f, 310r). 315r) includes a vehicle body roll angle variable unit 318 (318f, 318r) that controls the roll angle of the vehicle body 311 and a wheel roll angle variable unit 319 (319f, 319r) that controls the roll angle of the wheels 310 (310f, 310r). It is characterized by providing. That is, the variable section 315 (315f, 315r) can tilt the vehicle body 311 and the wheels 310 (310f, 310r) independently of the road surface.

  The vehicle body roll angle variable unit 318 can change the height of one and the other of the front wheels and / or the height of one and the other of the rear wheels, for example, by changing the length of the upper arm of the tire with a hydraulic piston or the like. The roll angle of the vehicle body 311 is controlled by making the difference. The wheel roll angle variable unit 319 controls the roll angle of the wheel 310 by making it possible to change the angle of the wheel 310 with respect to the road surface using, for example, a suspension or a hydraulic piston.

  As in the first and second embodiments, the controller 316 is configured by, for example, a microcomputer and the steering which is the ratio of the roll angle and the steering wheel angle of the vehicle body 311 according to a control program stored therein. The ratio is defined as a function of speed, and a steering ratio corresponding to the vehicle speed is output to the variable unit 315. In the present embodiment, similarly to the second embodiment, the controller 316 operates the vehicle body roll angle variable unit 318 and the wheel roll angle variable unit 319 with the operation unit 317, whereby the roll angle and the wheel of the vehicle body 311 are changed. The roll angle of 310 can be adjusted. Furthermore, the present embodiment is characterized in that the roll angle control is performed independently for the front wheel 310f and the rear wheel 310r.

  Thus, in this embodiment, the controller 316 changes the relationship between the roll angle of the vehicle body 311 and the roll angle of the wheel 310 by adjusting the roll angle of the vehicle body 311 and the roll angle of the wheel 310, and The canvas stiffness of the wheel 310 when the automobile 301 turns is adjusted. Similarly to the second embodiment, the controller 316 determines the magnitude relationship between the roll angle of the vehicle body 311 and the roll angle of the wheels 310 (310f, 310r), and the determination result of the determination unit 316a. A command unit 316b that instructs to adjust the vehicle body roll angle variable unit 318 and the wheel roll angle variable unit 319 so that the wheels 310 (310f, 310r) have a desired canvas stiffness is provided.

  In the present embodiment, by providing the controller 316, the variable unit 315 is operated by the operation unit 317 via the controller 316 when turning, and the relationship between the roll angle of the vehicle body 311 and the wheel 310 is determined by the front wheel 310f and the rear wheel. It can be changed in each of 310r. Specifically, the controller 316 first controls the vehicle body roll angle variable unit 318f and the wheel roll angle variable unit 319f of the front wheel 310f within a predetermined time from the start of turning of the automobile 301 to control the roll angle and wheel ( The relationship with the roll angle of the front wheel 310f is changed. Then, after a predetermined time has elapsed, the vehicle body roll angle variable unit 318r and the wheel roll angle variable unit 319r are controlled to change the relationship between the roll angle of the vehicle body 311 and the roll angle of the wheel (rear wheel) 310r.

  That is, in this embodiment, the lean angle control is performed on the vehicle body 311 and the front wheel 310f until the front wheel 310f side reaches a steady state at the start of turning, and the vehicle body 311 and the rear wheel after the rear wheel 310r also enters a turning operation after a predetermined time. The lean angle of 310r is controlled. In this way, the lean angle control is performed from the front wheel side, and the rear wheel side lean angle control is delayed to achieve a balanced state when turning, so that the automobile 301 does not slide diagonally and cornering at the start of turning is performed. The stability of the can be further increased. Note that the “predetermined time” mentioned here refers to, for example, the time during which the automobile 301 travels the wheel base that is the distance between the front wheel 310f and the rear wheel 310r.

  As described above, in the automobile 301 of the present embodiment, the relationship between the roll angle of the vehicle body 311 and the roll angle of the wheel 310 is changed between the front wheel 310f and the rear wheel 310r while adjusting the variable unit 315 by the operation unit 317 via the controller 316. Can be changed separately. Therefore, the operation unit 317 is adjusted so that the canvas stiffness of the front wheel 310f at the start of turning of the automobile 301 becomes a desired size, and the canvas stiffness of the rear wheel 310r is adjusted to a desired size after a predetermined time has elapsed. Since it can be adjusted by the portion 317, the cornering operation from the start of turning to the steady state proceeds smoothly. That is, in the present embodiment, cornering of the automobile 301 in the nonlinear characteristic region at the start of turning can be stabilized. In addition, the automobile 301 according to the present embodiment can be changed to a wide range of vehicle characteristics from a sports car type to a family use type with a single automobile 301 as in the second embodiment, and the automobile 301 is designed. In doing so, the design range of the vehicle is greatly expanded. In particular, in the present embodiment, as in the second embodiment, since it is applied to a car 301 called personal mobility having a small and light weight compared to a normal car and having an elongated car body 311, it can be flexibly changed by a driver like a motorcycle. Thus, the vehicle can be used as a highly safe vehicle that ensures stability during turning while having vehicle characteristics that can be changed. That is, the personal mobility applied as the automobile 301 according to the present embodiment is an unexpected accident while the driver can flexibly adjust the roll angle of the vehicle body 311 and the wheel 310 when turning, like a motorcycle, and change the vehicle characteristics. Thus, it is possible to ensure safety that the driver is protected from an external impact or the like by the vehicle body 311 when the vehicle crashes or falls. Note that the motion control device 320 and the motion control method of the automobile 301 according to the present embodiment have been created by the present inventor after kinematically verifying according to the following description.

3.2. Nonlinear Vehicle Model Next, the nonlinear vehicle model in the automobile according to the present embodiment will be described. Non-linear characteristics of the target vehicle motion during a sharp turn are mainly caused by tire characteristics and a large roll angle. First, consider the tire nonlinear tire model. In the present embodiment, a tire model in which the longitudinal force and the lateral force interfere with each other is guided. This model is the model shown in the motion analysis of motorcycles.

3.2.1 Tire characteristics First, the i-th tire is examined. When the camber angle of this tire is φ _i , the side slip angle is α _i , and the slip ratio is s _i , the lateral force F _yi and the longitudinal force F _xi are expressed by a linear model as shown in the following equations (37) and (38). Think.

Next, vector synthesis of both forces acting on one wheel is performed. In this case, the angle λ _i formed by the resultant force with respect to the longitudinal force is given by the following equation (39).

Further, the magnitude of the vector-combined tire force is given by the following equation (40).

Here, when a load reaction force of the tire and N _i, the coefficient of friction of the apparent force due to the linear model is given by (41) below.

  Considering the friction characteristics between the road surface and the tire as a single tire, the friction coefficient is usually about 0.8 to 1 on a dry asphalt road surface. Therefore, the tire force characteristics are expressed using a function that converges to the friction coefficient on the apparent friction coefficient general road. The following formula (42) defined as the magic formula is used as the friction conversion formula constructed above.

Each coefficient in this equation is determined to adjust the value and peak position of the friction coefficient, and each coefficient in {} is determined to set the slope at the origin to 1, and the result Is shown in FIG. Next, using the equation (42), the tire force F _Ti is given by the following equation (43).

When this axial force is decomposed in each axial direction, the longitudinal force and lateral force are given by the following equations (44) and (45), respectively.

The result of the interference between the longitudinal force and the cornering force by the tire model here is shown in FIG. In FIG. 22, calculation was performed assuming that the normal force applied to the tire is 1500 N.

3.2.2 Acceleration at the center of gravity Next, the acceleration at the center of gravity will be described. Here, a nonlinear equation of motion is derived using the tire model described above. Since the center of gravity of this vehicle is largely tilted around the x-axis during travel, the direction of motion around the z-axis changes when using the fixed center-of-gravity coordinate system used in passenger cars, etc., and the sideslip angle, centripetal acceleration, etc. Coordinate conversion is required each time when handling. Therefore, in this embodiment, the origin of the dynamic coordinate system is set at the center of the left rear wheel ground, and the movement of the center of gravity is measured from this position. Further, since it has a large roll angle in the same direction as the two-wheeled vehicle, the SAE coordinate system is used, and the A-x _A and y _A planes are located on the O-X and Y planes of the inertial coordinate system. Show. Thus, the position vector r _G of the scaled centroid point from the inertial coordinate system is described by (46) below through the left rear wheel contact center A.

Moreover, the dimension of each part of the vehicle in the above-mentioned tire model is shown in FIGS. 24 (A) and (B). Here, these depend on the mechanism relating to the camber angle, but here, as in the first embodiment, a mechanism in which the left and right tires move up and down in parallel is adopted. Using these symbols, the position vector of the tire model is expressed by the following equation (47). Note that unit vectors representing the directions of the dynamic coordinate systems A- _xA , _yA , and _{zA at} the point A are denoted as e _xA , e _yA , and e _zA , respectively.

  Therefore, when the above equation (47) is differentiated with respect to time, the speed becomes the following equation (48).

Similarly, when the above equation (48) is differentiated, the acceleration becomes the following equation (49).

Further, the speed ν _A of the point A viewed from the inertial coordinate system is given by the following equation (50).

  When this is differentiated with respect to time, the acceleration at point A is given by the following equation (51).

  Therefore, the speed of the center of gravity is given by the following equation (52) by adding the speed of the point A and the speed of the center of gravity viewed from the point A.

  Similarly, the acceleration at the center of gravity is given by the following equation (53).

3.2.3 Side slip angle in each tire The speed at point A was determined by the above-described equation (50). Therefore, the speed at the contact position of another tire is obtained using this. In addition, the symbol of each tire is shown in FIG. 23 mentioned above. The position vector of each tire viewed from point A is expressed by the following equation (54).

Here, the treads of the front and rear wheels are the same, and the wheel base is the same on the left and right. Therefore, the speed at each contact point is obtained by adding the translation speed and the tangential speed by rotation. Here, since the point A is the reference, the translation speed is the speed of the point A, and the tangential speed obtained by the outer product may be added to this, which is expressed by the following equation (55).

Similarly, the speed of the front wheels is given by the following equations (56) and (57). Here, ω in the equations (56) and (57) has the relationship of the following equation (58).

  Therefore, the side slip angle in each tire is given by the following equation (59). Here, only the front wheels are steered, and the left and right wheels are at the same angle δ.

3.2.4 Equation of motion Since the vehicle examined above has a large roll angle, the degree of freedom of motion is the x-axis direction, the y-axis direction, the z-axis direction, the x-axis, the y-axis, and the z-axis. However, in this report, it is necessary to consider that the longitudinal speed is constant as the first step, fix the degrees of freedom around the x-axis direction and the y-axis, and consider four degrees of freedom. In this case, since the roll angle is determined by moving the left and right tires up and down, rotation around the roll axis is considered as shown in FIG. FIG. 25 is a view of the turning vehicle as seen from the rear. As shown in the first and second embodiments, this vehicle is configured to move the left and right wheels up and down so as to turn around a point O just below the center of gravity. In this case, when depressing the tire by the suspension, but the pressing force acts against the road surface reaction force from the road surface becomes N _C shown in FIG. Similarly, a downward reaction force is generated in the tire on the pushed-up side. These reaction forces become couples and give only moment to the vehicle. Next, the reaction forces of N _As and N _Bs are applied to these tires as a steady balance state, and road reaction force due to the operating force of each tire for rotation is added to this tire, but here the reaction force of the inner wheel ( vertical force component of a negative value) N _C is considered without exceeding the run reaction force N _iS constant speed in the steady state. The center of gravity moves in the lateral direction by this roll motion, but this is already taken into account in the acceleration and is described in the inertia term. Therefore, the roll motion is simply expressed by the following equation (60).

  In addition, since the following self-aligning torque and camber torque act on the steering system tire, the steering torque includes the following equation (61) including the gear ratio i.

In the present embodiment, considering the constant speed traveling, the equation of motion, y with respect to the direction _A, (62) below, for around z _A-axis, as shown in (63) below, y at the center of gravity point _A think direction and z _a axis of the balance, respectively.

  Further, in order to pay attention to the response of the centroid point, the centroid point side slip angle β is defined on the XY plane and defined as the following equation (64).

3.3. Simulation Next, in this chapter, the motion analysis of the vehicle according to the present embodiment is performed using the motion equation constructed in the previous chapter.

3.3.1 Calculation conditions In the vehicle shown in this embodiment, the roll angle control is performed using the initial position change of the left and right suspensions. Further, as shown in the first and second embodiments, both the front wheel actual rudder angle and the roll angle are connected by a mechanism having a variable link ratio according to the steering angle, and both of them are handled as input. Table 2 shows the vehicle specifications used for this calculation. In the present embodiment, the response in a region where the centripetal acceleration is relatively high is examined using the above-described nonlinear tire model. The speed is assumed to change up to 30 m / s, and the change in the steering ratio and the maximum roll angle are assumed to be 30 deg.

3.3.2 Effects of speed changes First, we will understand the effects of speed changes that have a large effect on vehicle characteristics. 26A to 26E show the influence of the speed change with other conditions being constant. As shown in FIGS. 26 (A) to (E), it can be seen that the side slip and yaw rate gains decrease and the attenuation decreases as the speed increases. Further, under this calculation condition, the centripetal acceleration is about 0.7 G at 30 m / s, and it can be seen that the centripetal acceleration in the vicinity of the steady state hardly changes due to the non-linear effect of the tires around this. Under this calculation condition, it is understood that there is a tire characteristic limit around here. Therefore, in the subsequent analysis, the effect of various parameters in this speed region will be examined.

3.3.3 Effect of Change in Target Roll Angle Next, responses to changes in the target roll angle are shown in FIGS. 27 (A) to (E). When this target roll angle is small (10 deg), the centripetal acceleration is 0.3 G, which is considered to be a substantially linear region. By setting the target roll angle to 20 deg, the centripetal acceleration becomes a little less than 0.6 G, and it can be seen from the yaw rate response that the centripetal acceleration is in the non-linear region, and the vibration response appears and the attenuation decreases. . Furthermore, in the case of this vehicle, the main centripetal force is canvas last, but as shown in the yaw rate response, the rise of the response is relatively slow, and it can be seen that the obstacle avoidance performance and the like are reduced.

3.3.4 Influence of Steering Ratio Change The steering ratio is defined in the first embodiment described above, and the roll angle and the actual steering angle are determined according to the steering angle controlled by the driver. The main centripetal force in the steady state of the vehicle is the canvas last as described above. Therefore, FIGS. 28A to 28E show analysis results when the actual steering angle, which is an auxiliary position, is changed mainly for the vehicle body roll angle in the steady circular turning characteristics. In this analysis, the target roll angle is set to 30 degrees and the actual rudder angle is changed. However, in the case of this analysis condition, it can be seen that the actual rudder angle is about 2 deg and near the limit value of the centripetal acceleration. In this case, the tire side slip angle is greatly affected, and it can be seen that the cornering force is greatly influenced by the total centripetal force. Furthermore, when the actual rudder angle is set to 0, it can be seen that the rise of the yaw rate response is further delayed, which is not preferable from the viewpoint of obstacle avoidance performance. Therefore, it is understood that the front wheel actual steering angle needs to be used effectively in order to increase the response as much as possible.

3.4. Addition of actual rudder angle at the start of exercise Next, addition of an actual rudder angle at the start of exercise in the automobile according to this embodiment will be described. In the above-described analysis, it was shown that turning around the canvas last slows the rise of the response and is not preferable from the viewpoint of obstacle avoidance. This is due to the fact that the camber angles of the front and rear wheels are the same and the lateral force generated by the front and rear wheels is not significantly different, so the yaw moment of the centripetal force around the canvas last is relatively small. Is done. However, it is necessary to generate a yaw moment at the initial stage of motion control, considering that it does not become a problem when the steady state is reached. In order to realize this, it is necessary to consider additional steering. Therefore, semi-sinusoidal steering is added at the beginning of the rise and the effect is confirmed. In the analysis, FIGS. 29A to 29E show the results of changing the maximum steering angle in consideration of half-cycle steering of a sine wave of one cycle of 0.4 s. From this analysis result, by using additional steering, it is possible to suppress the peak of the side slip angle at the center of gravity that occurs early in the vehicle response, to further accelerate the rise of the yaw rate response, and to the rise of the centripetal acceleration. Has a great effect. It can also be seen that this addition of steering is effective in converging the response to the final stable value.

3.5. Conclusion In this embodiment, the response near the motion limit of the vehicle was examined using a nonlinear tire model, and the following conclusion was obtained. In other words, as a result of the derivation of the equation of motion including the nonlinear tire model, it was possible to grasp the outline of the response near the limit. Further, in the case of the vehicle centering on the canvas last shown so far in the present embodiment, it has been found that the generation of the yaw moment at the initial stage of motion is relatively small and the rise of the yaw rate response is slightly slow. Furthermore, in order to ensure obstacle avoidance performance and the like, it is proposed to add additional steering at the initial stage of the steering response. It was shown that this additional steering can ensure the responsiveness of the yaw rate response, and that the initial peak response of the lateral slip angle of the center of gravity can be suppressed.

  Although each embodiment of the present invention has been described in detail as described above, it is easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. It will be possible. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the configuration and operation of the vehicle motion control device and the vehicle are not limited to those described in the embodiments of the present invention, and various modifications can be made.

101, 201, 301 Automobile, 110, 210, 310 Wheel (tire), 111, 211, 311 Car body, 112, 212, 312 Roll angle detector, 113, 213, 313 Handle angle detector, 113a, 213a, 313a Handle , 114, 214, 314 Vehicle speed detection unit, 115, 215, 315 Variable unit, 116, 216, 316 Controller, 120, 220, 320 Motion control device, 217, 317 Operation unit, 218, 318 Car body roll angle variable unit, 219 319 Wheel roll angle variable part

Claims (14)

  When controlling the movement of an automobile with three or more wheels, the steering ratio, which is the ratio of the roll angle and the steering wheel angle of the vehicle body that can be controlled by the roll angle, is defined as a function of speed, and can be varied according to the vehicle speed. Motor control method for car The function is defined by a steer index SI determined to be a predetermined stability factor Κ _δ and a predetermined side slip factor Κ _β , and a ratio κ _A between an actual canvas stiffness and a reference canvas stiffness. The motor control method of a motor vehicle as described in 1.
SI is K _SB -ζK _SA
ζ = K _CB / K _CA
K _SA and K _SB are cornering stiffness for front and rear wheels K _CA and K _CB are canvas stiffness for front and rear wheels 3. The vehicle motion control method according to claim 1, wherein the steering ratio k (v) is provided so as to satisfy the following relational expression.
^{k (v) = v 2 /} gl (l + Κ δ v 2)
v is speed g is gravitational acceleration l is distance between front and rear wheels   The vehicle motion control according to any one of claims 1 to 3, wherein a relationship between a roll angle of the vehicle body and a roll angle of the wheel is changed to adjust a canvas stiffness of the wheel when the vehicle is turning. Method.   5. The vehicle motion control method according to claim 1, wherein the vehicle is personal mobility having at least two front wheels and at least one rear wheel. 6.   The relationship between the roll angle of the vehicle body of the front wheel and the roll angle of the wheel is changed within a predetermined time from the start of turning of the automobile, and the roll angle of the vehicle body and the wheel of the rear wheel after the predetermined time has elapsed. The vehicle motion control method according to claim 5, wherein the relationship with the roll angle is changed. A variable unit that controls at least the roll angle of the body of the automobile when controlling the movement of the automobile having three or more wheels when turning,
A vehicle that includes a controller that defines a steering ratio that is a ratio of a roll angle and a steering wheel angle of the vehicle body that can be controlled to a roll angle as a function of speed, and that outputs the steering ratio according to the vehicle speed of the vehicle to the variable unit. Motion control device. The function is defined by a steer index SI determined to be a predetermined stability factor Κ _δ and a predetermined side slip factor Κ _β , and a ratio κ _A between an actual canvas stiffness and a reference canvas stiffness. An automobile motion control device according to claim 1.
SI is K _SB -ζK _SA
ζ = K _CB / K _CA
K _SA and K _SB are cornering stiffness for front and rear wheels K _CA and K _CB are canvas stiffness for front and rear wheels The vehicle motion control apparatus according to claim 7 or 8, wherein the steering ratio k (v) is provided so as to satisfy the following relational expression.
^{k (v) = v 2 /} gl (l + Κ δ v 2)
v is speed g is gravitational acceleration l is distance between front and rear wheels An operation unit capable of operating the variable unit via the controller is further provided.
The variable unit includes a vehicle body roll angle variable unit that performs roll angle control of the vehicle body, and a wheel roll angle variable unit that performs roll angle control of the wheel,
The controller changes the relationship between the roll angle of the vehicle body and the roll angle of the wheel by operating the vehicle body roll angle variable unit and the wheel roll angle variable unit with the operation unit, and turns the vehicle The vehicle motion control apparatus according to claim 7, wherein the canvas stiffness of the wheel at the time is adjusted. The above controller
A determination unit for determining a magnitude relationship between the roll angle of the vehicle body and the roll angle of the wheel;
11. The apparatus according to claim 10, further comprising: a command unit that instructs to adjust the vehicle body roll angle variable unit and the wheel roll angle variable unit so that a desired canvas stiffness is obtained based on a determination result of the determination unit. Motor motion control device.   12. The vehicle motion control apparatus according to claim 7, wherein the vehicle is personal mobility having at least two front wheels and one or more rear wheels. The vehicle body roll angle variable part and the wheel roll angle variable part are provided on each of the front wheel and the rear wheel,
The controller controls the vehicle body roll angle variable unit and the wheel roll angle variable unit on the front wheel within a predetermined time from the start of turning of the vehicle, thereby determining the relationship between the roll angle of the vehicle body and the roll angle of the front wheel. And changing the relationship between the roll angle of the vehicle body of the rear wheel and the roll angle of the wheel by controlling the vehicle body roll angle variable unit and the wheel roll angle variable unit of the rear wheel after the predetermined time has elapsed. The vehicle motion control device according to claim 12. 3 or more wheels,
The car body,
An automobile comprising the automobile motion control device according to any one of claims 7 to 13.

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