Mobile

Abstract

To provide a moving body that is able to smoothly shift from one state to the other state, of a control state for stabilizing a posture of a vehicle body by inclination of a rear wheel relative to the vehicle body and a control state for stopping or restricting inclination of the rear wheel relative to the vehicle body.SOLUTION: A control device 40 of a moving body 1 determines a control input for operating inclination of a rear wheel 3r relative to a vehicle body 2, by linear combination of a first control input component for stabilizing a posture of the vehicle body 2 in a rolling direction and a second control input component for converging an inclination angle of the rear wheel 3r relative to the vehicle body 2 on zero. The control device controls an actuator 28 according to the control input and sets a first gain coefficient related to the first control input component and a second gain coefficient related to the second control input component so that, as a value of one gain coefficient increases, a value of the other gain coefficient decreases.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mobile body having a tiltable body, such as a two-wheeled vehicle. [Background technology]

[0002] Conventionally, there has been known a vehicle (two-wheeled vehicle) configured so that the rear wheels can be tilted in a roll direction (around the longitudinal axis of the vehicle body) relative to the vehicle body, as can be seen in, for example, Patent Documents 1 and 2. In this vehicle, by appropriately tilting the rear wheels using an actuator when the vehicle is stopped or traveling at low speed, it is possible to apply a moment in the roll direction to the vehicle body so as to stabilize the posture (inclination angle) of the vehicle body in the roll direction.

[0003] In the moving bodies shown in Patent Documents 1 and 2, the rear wheels are tilted in the roll direction relative to the body, but it is also possible to apply a moment in the roll direction to the body by tilting the front wheels in the roll direction relative to the body instead of the rear wheels. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-175638 [Patent Document 2] Japanese Patent Publication No. 2021-175639 Summary of the Invention [Problem to be solved by the invention]

[0005] In the mobile bodies as disclosed in Patent Documents 1 and 2, for example, when the mobile body is traveling at a relatively high speed, the posture of the body is highly stable without tilting the rear wheels relative to the body. In such a situation, it is desirable for the driver to smoothly tilt the body in the roll direction by shifting his or her own weight when turning, etc.

[0006] However, if the actuators are constantly controlled to stabilize the vehicle body posture, the driver's intentional attempt to tilt the vehicle body in the roll direction by shifting his or her weight may be hindered. This may cause the driver to feel uncomfortable or may impair the driver's control of the vehicle. This also applies when tilting the front wheels in the roll direction relative to the vehicle body instead of the rear wheels.

[0007] Therefore, it is desirable to be able to appropriately transition from one state, in which the actuator is controlled to stabilize the posture of the vehicle body by tilting the rear or front wheels relative to the vehicle body, to the other state, and in this case, it is desirable to be able to smoothly transition from one state to the other.

[0008] The present invention has been made in consideration of this background, and aims to provide a mobile body that can appropriately transition from one state to the other, between a state in which the operation of an actuator is controlled to stabilize the posture of the vehicle body by tilting the rear or front wheels relative to the vehicle body, and a state in which the operation of an actuator is controlled to stop or suppress the tilting of the rear or front wheels relative to the vehicle body, and that can perform this transition smoothly. [Means for solving the problem]

[0009] In order to achieve the above object, the moving body of the present invention is a moving body having a riding section for a driver and a vehicle body that can tilt in a roll direction relative to a road surface, front wheels and rear wheels that are arranged at an interval in the front-rear direction of the vehicle body, an actuator that can apply a moment in the roll direction to the vehicle body, and a control device that has a function of controlling the actuator so as to stabilize the attitude of the vehicle body in the roll direction, one of the front wheels and the rear wheels is a steering wheel, and the other wheel is a tilting wheel mounted on the vehicle body so as to be tiltable in a roll direction relative to the vehicle body, the actuator is configured to tilt the tilting wheel in a roll direction relative to the vehicle body, thereby applying a moment in the roll direction to the vehicle body, The control device is configured to determine a control input for operating the tilting of the tilting wheel relative to the vehicle body by a linear combination of a first control input component that stabilizes the posture of the vehicle body in the roll direction and a second control input component that converges the tilt angle of the tilting wheel relative to the vehicle body to zero, and to control the actuator according to the determined control input, and is configured to variably set a first gain coefficient related to the first control input component and a second gain coefficient related to the second control input component in the linear combination so that as the value of one of the first gain coefficient and the second gain coefficient increases, the value of the other decreases (first invention).

[0010] In the present invention, the term "road surface" is not limited to an outdoor road surface but may also include an indoor floor surface. Furthermore, the term "roll direction" refers to the direction around the longitudinal axis of the vehicle body. Furthermore, "stabilizing the posture of the vehicle body" refers to controlling the posture of the vehicle body in the roll direction to a target state (such as a dynamic equilibrium state) that can be stably maintained.

[0011] According to the present invention, a control input used to control an actuator is determined by a linear combination of the first control input component and the second control input component, and in this linear combination, a first gain coefficient related to the first control input component and a second gain coefficient related to the second control input component are variably set so that as one of the first gain coefficient and the second gain coefficient increases, the other decreases.

[0012] In this case, when the second gain coefficient is set to zero or a small value close to zero, the control input coincides or nearly coincides with the first control input component, and therefore, by controlling the actuator in accordance with the control input, tilt control of the tilting wheels is performed so as to stabilize the posture of the vehicle body in the roll direction.

[0013] Furthermore, when the first gain coefficient is set to zero or a small value close to zero, the control input coincides or nearly coincides with the second control input component, and therefore, by controlling the actuator in accordance with the control input, tilt control of the tilting wheels is performed so that the tilt angle of the rear wheels relative to the vehicle body converges to zero.

[0014] Then, by increasing the value of the first gain coefficient and decreasing the value of the second gain coefficient, the proportion of the control input that is occupied by the first control input component increases and the proportion that is occupied by the second control input component decreases. Similarly, by increasing the value of the second gain coefficient and decreasing the value of the first gain coefficient, the proportion of the control input that is occupied by the second control input component increases and the proportion that is occupied by the first control input component decreases.

[0015] Therefore, according to the present invention, by adjusting the first gain coefficient and the second gain coefficient, it is possible to appropriately transition from one state, in which the operation of the actuator is controlled to stabilize the posture of the vehicle body by tilting the tilting wheels (rear wheels or front wheels) relative to the vehicle body, to the other state, and it is also possible to smoothly transition from one state to the other.

[0016] In the first invention, it is preferable that the control device is configured to set the values ​​of the first gain coefficient and the second gain coefficient so that the sum of the first gain coefficient and the second gain coefficient becomes a predetermined value (second invention).

[0017] This allows the values ​​of the first gain coefficient and the second gain coefficient to be set so that an increase in the value of the first gain coefficient and an accompanying decrease in the value of the second gain coefficient, or an increase in the value of the second gain coefficient and an accompanying decrease in the value of the first gain coefficient, can be easily performed.

[0018] In the first or second invention, the control device may further include a maximum moment specifying unit that specifies a maximum moment that can be applied to the vehicle body by the actuator; a limit state quantity specifying unit that specifies a value of a predetermined type of state quantity related to the posture of the vehicle body in the roll direction as a limit state quantity at which the posture of the vehicle body in the roll direction can be stabilized by applying the maximum moment to the vehicle body; an attitude stability index value determining unit that determines an index value that represents a stability margin for the posture of the vehicle body in the roll direction from the current value of the predetermined type of state quantity and the value of the limit state quantity; and a control gain adjusting unit that adjusts the values ​​of each of the first gain coefficient and the second gain coefficient in accordance with the index value (third invention).

[0019] According to this, by adjusting the values ​​of the first gain coefficient and the second gain coefficient in accordance with the index value, the first gain coefficient and the second gain coefficient control gain can be adjusted to reflect the stability margin of the posture of the vehicle body in the roll direction. Here, the stability margin of the posture of the vehicle body indicates the margin (so-called stability margin) with which the stability of the posture of the vehicle body can be ensured, and the lower the stability margin of the posture of the vehicle body, the closer the posture state of the vehicle body is to the limit at which stability can be ensured.

[0020] Specifically, the higher the stability margin, the smaller the value of the first gain coefficient and the larger the value of the second gain coefficient, and the lower the stability margin, the larger the value of the first gain coefficient and the smaller the value of the second gain coefficient. Therefore, when the stability margin is high, the control to stabilize the posture of the vehicle body in the roll direction is weakened and the control to stop or suppress the tilting of the tilting wheels relative to the vehicle body is strengthened, so the driver can easily tilt the vehicle body by shifting his or her weight, etc.

[0021] Furthermore, when the stability margin is low, the control to stabilize the posture of the vehicle body in the roll direction is strengthened, and the control to stop or suppress the tilting of the tilting wheels relative to the vehicle body is weakened, thereby improving the stability of the posture of the vehicle body in the roll direction. Therefore, it is possible to appropriately achieve both stability in the posture of the vehicle body in the roll direction and ease of control by the driver.

[0022] In the third aspect of the invention, it is preferable that the predetermined type of state quantity is any one of a set of a tilt angle and a tilt angular velocity in a roll direction of the vehicle body, a function value of the tilt angle and the tilt angular velocity, and a set of a movement amount and a movement velocity of an inverted pendulum mass point in a model that represents the behavior of the vehicle body and includes the inverted pendulum mass point, and a function value of the movement amount and the movement velocity (fourth aspect of the invention).

[0023] This allows a state quantity that has a high correlation with the stability margin of the attitude in the roll direction of the vehicle body to be used as the predetermined type of state quantity. Therefore, an index value that appropriately represents the stability margin of the attitude in the roll direction of the vehicle body can be determined. Ultimately, it becomes possible to adjust the values ​​of the first gain coefficient and the second gain coefficient so as to appropriately reflect the stability margin of the attitude in the roll direction of the vehicle body.

[0024] In the third or fourth invention, it is preferable that the predetermined type of state quantity is a value of a divergence component related to a set of a tilt angle and a tilt angular velocity in a roll direction of the vehicle body, or a value of a divergence component related to a set of a movement amount and a movement velocity of an inverted pendulum mass point in a model that represents the behavior of the vehicle body and includes the inverted pendulum mass point (fifth invention).

[0025] Here, the value of the divergence component related to the set of tilt angle and tilt angular velocity in the roll direction of the vehicle body is a component that diverges due to the free movement of the set of tilt angle and tilt angular velocity in the roll direction of the vehicle body, and is a value obtained by linearly combining, in the form of (tilt angle deviation + tilt angular velocity deviation / ωn), a tilt angle deviation which is the deviation between the actual tilt angle in the roll direction of the vehicle body and its target value, and a tilt angular velocity deviation which is the deviation between the actual tilt angular velocity in the roll direction of the vehicle body and its target value.

[0026] Similarly, the value of the divergence component related to the set of the movement amount and movement velocity of the inverted pendulum mass point is a component that diverges due to the free movement of the set of the movement amount and movement velocity of the inverted pendulum mass point, and is a value obtained by linearly combining, in the form of (movement amount deviation + movement velocity deviation / ωn), a movement amount deviation which is the deviation between the movement amount of the inverted pendulum mass point corresponding to the actual tilt of the vehicle body in the roll direction and its target value, and a movement velocity deviation which is the deviation between the movement velocity of the inverted pendulum mass point corresponding to the actual tilt of the vehicle body in the roll direction and its target value.

[0027] The divergence component has a high correlation with the stability margin of the attitude in the roll direction of the vehicle body. Therefore, it is possible to determine an index value that appropriately represents the stability margin of the attitude in the roll direction of the vehicle body. Ultimately, it becomes possible to adjust the values ​​of the first gain coefficient and the second gain coefficient so as to appropriately reflect the stability margin of the attitude in the roll direction of the vehicle body. The divergence component corresponds to the function value in the fourth aspect of the present invention.

[0028] In any of the third to fifth aspects of the invention, the index value may be an index value that represents the degree of deviation of the current value of the predetermined type of state quantity from the value of the limit state quantity (sixth aspect).

[0029] Here, the closer the current values ​​of the predetermined types of state quantities are to the limit state quantities, the lower the margin for stabilization of the vehicle body's posture, and therefore the stability margin of the vehicle body's posture can be considered to be low. Therefore, by using an index value representing the degree of deviation of the current values ​​of the predetermined types of state quantities from the values ​​of the limit state quantities as the index value representing the stability margin, it is possible to determine an index value that appropriately represents the stability margin of the vehicle body's posture. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1A is a side view of the moving body of the embodiment, and FIG. 1B is a rear view of the main part of the moving body of the embodiment. [Figure 2] FIG. 2 is a block diagram showing a configuration related to control of a moving body according to an embodiment. [Figure 3] FIG. 2 is a diagram showing a model representing the behavior of a moving object according to the embodiment. [Figure 4] FIG. 3 is an explanatory diagram relating to the processing of the control device shown in FIG. 2; [Figure 5] FIG. 3 is an explanatory diagram relating to the processing of the control gain adjuster shown in FIG. 2; DETAILED DESCRIPTION OF THE INVENTION

[0031] An embodiment of the present invention will be described below with reference to Figs. 1A to 5. Referring to Figs. 1A and 1B, a moving body 1 exemplified in this embodiment is, for example, a two-wheeled vehicle. This moving body 1 includes a body 2 and front wheels 3f and rear wheels 3r arranged at an interval in the fore-and-aft direction of the body 2. In this embodiment, the front wheels 3f and rear wheels 3r correspond to the steering wheels and tilting wheels, respectively, in the present invention. Note that Figs. 1A and 1B schematically illustrate the main components of the moving body 1.

[0032] Here, in the following explanation, the "front-rear direction" and "left-right direction" of the vehicle body 2 respectively refer to the direction perpendicular or nearly perpendicular to the axles of the front wheels 3f and rear wheels 3r, and the direction parallel or nearly parallel to the axles of the front wheels 3f and rear wheels 3r, when the moving body 1 is viewed from above (when the moving body 1 is projected onto a horizontal plane) in a straight-ahead driving posture (the same posture as when driving straight).

[0033] In this case, the "front-rear direction" and "left-right direction" of the vehicle body 2 are not limited to directions parallel to a horizontal plane in space, but may also be directions inclined relative to the horizontal plane. More specifically, the straight running posture of the mobile body 1 is the posture of the mobile body 1 in a state in which the axles of the front wheels 3f and rear wheels 3r are parallel or nearly parallel to each other, and the front wheels 3f and rear wheels 3r are upright perpendicular or nearly perpendicular to the horizontal plane. Moreover, the "up-down direction" of the vehicle body 2 means a direction that coincides with or nearly coincides with the vertical direction when the vehicle 1 is in a straight-ahead traveling posture.

[0034] 1A and 1B, a three-axis Cartesian coordinate system is assumed in which the front-to-rear direction of the vehicle body 2 of the vehicle 1 in a straight-ahead posture is the X-axis direction, the left-to-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction. The origin of this three-axis Cartesian coordinate system is the intersection of the vertical axis (Z-axis) passing through the center of gravity G of the vehicle 1 in a straight-ahead posture and the horizontal plane (XY coordinate plane) that is the contact surface (road surface) of the front wheels 3f and rear wheels 3r.

[0035] The vehicle body 2 has a head pipe 2a at its front end. A seat 4 is attached to the top surface of the vehicle body 2 as a riding section for the driver, on which the driver can sit astride. The vehicle body 2 of the mobile unit 1 in a straight-ahead traveling posture can tilt together with the front wheels 3f and rear wheels 3r in the roll direction (the direction around the axis in the fore-and-aft direction of the vehicle body 2) with respect to the contact surfaces (road surface) of the front wheels 3f and rear wheels 3r.

[0036] The front wheel 3f is mounted to the front of the vehicle body 2 via a front wheel support mechanism 10. The front wheel support mechanism 10 may have the same structure as a front wheel support mechanism of a normal motorcycle, for example. The front wheel support mechanism 10 in the illustrated example has a front fork 11 including, for example, a damper (not shown), and the front wheel 3f is journaled to the lower end of the front fork 11 via a front wheel axle unit 12.

[0037] The front fork 11 is mounted to the vehicle body 2 so as to be rotatable together with the front wheel 3f about a front-wheel-side steering axis Cf, which is the axis of the head pipe 2a of the vehicle body 2. The handlebars 13 mounted on the upper side of the head pipe 2a are connected to the front fork 11 so that, when a rider seated on the seat 4 operates the handlebars 13, the front fork 11 rotates together with the front wheel 3f about the axis of the head pipe 2a. This makes it possible to steer the front wheel 3f by operating the handlebars 13.

[0038] Although not shown in Fig. 1A, in this embodiment, the front wheel support mechanism 10 is equipped with an actuator 14 (shown in Fig. 2; hereinafter referred to as the front wheel steering actuator 14) for steering the front wheel 3f. The front wheel steering actuator 14 is configured, for example, by an electric motor with a speed reducer. The front wheel steering actuator 14 is mounted on the vehicle body 2 so as to transmit a rotational driving force about the front wheel steering axis Cf to the front fork 11.

[0039] The rear wheel 3r is mounted to the rear of the vehicle body 2 via a rear wheel support mechanism 20. The rear wheel support mechanism 20 is configured to be able to swing the rear wheel 3r in a pitch direction (a direction around the axis in the left-right direction of the vehicle body 2) relative to the vehicle body 2, and is also configured to be able to tilt the rear wheel 3r in a roll direction relative to the vehicle body 2.

[0040] For example, the mechanism described in Patent Document 1 can be used as the rear wheel support mechanism 20. In this case, as shown in Fig. 1B, the rear wheel support mechanism 20 includes a four-bar link mechanism 23 including four links 24a to 24d: a first link 24a and a second link 24b arranged to extend in the left-right direction of the vehicle body 2 with a gap between them in the up-down direction of the vehicle body 2, a third link 24c connecting left end portions of the first link 24a and the second link 24b, and a fourth link 24d connecting right end portions of the first link 24a and the second link 24b.

[0041] In this four-bar link mechanism 23, the third link 24c and the first link 24a are connected together, the third link 24c and the second link 24b are connected together, the fourth link 24d and the first link 24a are connected together, and the fourth link 24d and the second link 24b are connected together via joints 25a, 25b, 25c, and 25d, each having a rotation axis in the longitudinal direction of the vehicle body 2. The distance between the rotation axes of the joints 25a and 25c at both ends of the first link 24a is set to be smaller than the distance between the rotation axes of the joints 25b and 25d at both ends of the second link 24b.

[0042] One of the first link 24a and the second link 24b, for example, the lower first link 24a, is connected to the rear of the vehicle body 2 via a swing arm 21. The end of the swing arm 21 on the vehicle body 2 side is journaled via a pivot shaft 21a so as to be able to swing in the pitch direction (the direction around the axis in the left-right direction of the vehicle body 2) relative to the vehicle body 2, and the end on the first link 24a side is fixed to the first link 24a. This allows the entire four-bar link mechanism 23 to swing in the pitch direction together with the swing arm 21 relative to the vehicle body 2.

[0043] A suspension mechanism 22 that expands and contracts in accordance with the swing of the swing arm 21 relative to the vehicle body 2 is interposed between the swing arm 21 and a portion of the vehicle body 2 on the rear side of the pivot shaft 21a. The suspension mechanism 22 is, for example, a spring in Fig. 1A, but may also include a damper.

[0044] The rear wheel 3r is journaled to the rear end of a support arm 26 that extends rearward from the upper second link 24b of the first link 24a and second link 24b of the four-bar link mechanism 23 via a rear-wheel axle unit 27. The support arm 26 can be disposed on either the left or right side of the rear wheel 3r, or on both sides.

[0045] An actuator 28 is attached to the four-bar link mechanism 23 to rotate the links connected at each of the joints 25a to 25d relative to one another. In this embodiment, an actuator 28 is attached to one of the four joints 25a to 25d, for example, joint 25c, to rotate the fourth link 24d relative to the first link 24a about the rotation axis of the joint 25c. The actuator 28 is an actuator for tilting the rear wheel 3r in the roll direction relative to the vehicle body 2, and is configured, for example, by an electric motor with a reducer. Hereinafter, the actuator 28 will be referred to as the rear wheel tilting actuator 28.

[0046] By operating the rear wheel tilting actuator 28, the fourth link 24d is driven to rotate about the rotation axis of the joint 25c relative to the first link 24a, and the links connected at the joints 25a to 25d rotate relative to each other in an interlocking manner. As a result, as shown in FIG. 1B, the rear wheel 3r moves laterally relative to the vehicle body 2 while tilting in the roll direction relative to the vehicle body 2.

[0047] In this case, when the actuator 28 is operated to tilt the rear wheel 3r to the left of the vehicle body 2, as illustrated in FIG. 1B , the rear wheel 3r moves to the left relative to the vehicle body 2 while tilting to the left (counterclockwise as viewed from behind the vehicle 1) relative to the vehicle body 2. Conversely, when the actuator 28 is operated to tilt the rear wheel 3r to the right of the vehicle body 2, the rear wheel 3r moves to the right relative to the vehicle body 2 while tilting to the right (clockwise as viewed from behind the vehicle 1), which is the opposite of the above. In this embodiment, tilting the rear wheel 3r in the roll direction relative to the vehicle body 2 in this manner corresponds to steering the rear wheel 3r. Hereinafter, the actuator 28 that tilts the rear wheel 3r relative to the vehicle body 2 by driving the four-bar linkage 23 will be referred to as the rear-wheel tilting actuator 28.

[0048] Supplementally, in the mobile body 1 of this embodiment having the four-bar link mechanism 23 as described above, the tilting of the rear wheels 3r in the roll direction relative to the vehicle body 2 (steering of the rear wheels 3r) does not occur around a single tilting central axis. However, the intersection line Cr between the wheel width central plane of the rear wheels 3r (a plane that passes through the center of the rear wheels 3r and is perpendicular to the axle of the rear wheels 3r) when the rear wheels 3r are not tilted in the roll direction relative to the vehicle body 2 and the wheel width central plane of the rear wheels 3r when the rear wheels 3r are tilted in the roll direction relative to the vehicle body 2 extends in the fore-and-aft direction of the vehicle body 2 below the contact patch of the rear wheels 3r, as shown in FIG. 1B . This intersection line Cr corresponds to a pseudo tilting center line of the rear wheels 3r. Hereinafter, this intersection line Cr will be referred to as a rear steering axis Cr.

[0049] The rear wheel support mechanism 20 further includes an actuator 29 (shown in FIG. 1A) for adjusting the amount of swing in the pitch direction of the rear wheel 3r relative to the vehicle body 2. This actuator 29 (hereinafter referred to as the rear wheel pitch movement actuator 29) is configured, for example, by an electric motor with a speed reduction mechanism, and is attached to the vehicle body 2 or the swing arm 21 so as to be able to swing the swing arm 21 around the axis of the pivot shaft 21a relative to the vehicle body 2.

[0050] By operating this rear wheel pitch movement actuator 29, it is possible to adjust the amount of swing in the pitch direction of the rear wheel 3r relative to the vehicle body 2. For example, by operating the rear wheel pitch movement actuator 29 in conjunction with the tilt (steering) of the rear wheel 3r in the roll direction, it is possible to maintain a substantially constant height of the seat 4 of the vehicle body 2. The rear wheel pitch movement actuator 29 may be incorporated into the suspension mechanism 22 so that the stroke length of the suspension mechanism 22 can be adjusted.

[0051] As described above, the rear wheel support mechanism 20 of this embodiment includes the swing arm 21, the suspension mechanism 22, the four-bar link mechanism 23, the support arm 26, the actuator 28, and the rear wheel pitch movement actuator 29.

[0052] The moving body 1 is provided with an actuator 30 (shown in FIG. 1A) that rotates either the front wheel 3f or the rear wheel 3r, for example, the rear wheel 3r, as the traveling actuator 30 of the moving body 1. The traveling actuator 30 is configured, for example, by an electric motor with a speed reduction mechanism, and is assembled to the rear wheel-side axle unit 27.

[0053] The traveling actuator may be mounted on the front wheels 3f so as to be able to rotationally drive the front wheels 3f, or may be mounted on each of the front wheels 3f and the rear wheels 3r so as to be able to rotationally drive both the front wheels 3f and the rear wheels 3r. The traveling actuator may also be mounted on the vehicle body 2 so as to be able to rotationally drive one or both of the front wheels 3f and the rear wheels 3r via an appropriate power transmission mechanism.

[0054] The moving body 1 further includes a control device 40 having the function of controlling the operation of the front wheel steering actuator 14, the rear wheel tilting actuator 28, the rear wheel pitch movement actuator 29, and the traveling actuator 30, and is also equipped with, as sensors for detecting the operating state of the moving body 1, a wheel speed sensor 51 capable of detecting the wheel speed of the front wheels 3f, a front wheel steering angle sensor 52 capable of detecting the steering angle of the front wheels 3f (rotation angle around the front wheel steering axis Cf), an actuator rotation angle sensor 53 capable of detecting the rotation angle of the rear wheel tilting actuator 28, and an inertia sensor 54 capable of detecting the acceleration in three axial directions and the angular velocity in three axial directions of the vehicle body 2.

[0055] The wheel speed sensor 51, the front wheel steering angle sensor 52, and the actuator rotation angle sensor 53 are configured by, for example, a rotary encoder, a resolver, etc. The inertial sensor 54 is configured by a combination of an acceleration sensor and an angular velocity sensor.

[0056] The control device 40 is configured by one or more electronic circuit units including a processor such as a microcomputer, memories such as RAM and ROM, an interface circuit, etc., and receives the detection outputs of the above-mentioned sensors 51 to 54 as input.

[0057] The control device 40, using the implemented hardware configuration and program (software configuration), can detect or estimate various state quantities of the moving body 1 (such as the traveling speed of the moving body 1 (traveling speed of the vehicle body 2), the front wheel steering angle (δf shown in FIG. 1A) which is the rotation angle of the front wheels 3f around the front wheel steering axis Cf, the rear wheel steering angle (δr shown in FIG. 1B) which is the tilt angle in the roll direction of the rear wheels 3r relative to the vehicle body 2, the vehicle body roll angle (φb shown in FIG. 1B) which is the tilt angle in the roll direction of the vehicle body 2, the yaw rate of the vehicle body 2, etc.) from the detection outputs of the sensors 51 to 54, and can also control the operation of each of the above-mentioned actuators 14, 28, 29, and 30.

[0058] The control device 40 is capable of controlling the roll direction attitude (tilt angle) of the vehicle body 2 through operation control of the rear-wheel tilting actuator 28 (operation control related to the tilting operation of the rear wheels 3r relative to the vehicle body 2). For this control, the control device 40 has the following functions: a maximum moment specifying unit 41 that specifies a maximum roll moment, which is the maximum moment in the roll direction that can act on the vehicle body 2; a limit state quantity specifying unit 42 that specifies limit state quantities (limit state quantities related to the attitude of the vehicle body 2 in the roll direction) that can bring the lateral movement amount P1y and lateral movement velocity P1y_dot of the first mass point 61 close to target values ​​when the maximum roll moment is applied to the vehicle body 2; an attitude stability index value determining unit 43 that determines an index value (hereinafter referred to as attitude stability index value) that indicates a stability margin for the attitude of the vehicle body 2 in the roll direction; and a control gain adjusting unit 44 that adjusts a control gain related to operation control of the rear-wheel tilting actuator 28, as shown in FIG.

[0059] The processing of the control device 40 relating to the roll direction attitude control of the vehicle body 2 will be specifically described below. When the traveling speed of the moving body 1 is in the low speed range (including when the moving body 1 is stopped), the control device 40 controls the operation of the rear wheel tilting actuator 28 to apply a moment in the roll direction (roll moment) to the vehicle body 2 so as to stabilize the attitude of the vehicle body 2 in the roll direction. Hereinafter, this control will be referred to as attitude stabilization control. Note that stabilizing the attitude of the vehicle body 2 in the roll direction means controlling the attitude of the vehicle body 2 in the roll direction to a required target state that can be maintained stably.

[0060] This attitude stabilization control is performed by an algorithm based on an equivalent two-mass decomposition inverted pendulum model as a model representing the behavior of the moving body 1. The equivalent two-mass decomposition inverted pendulum model (hereinafter simply referred to as the two-mass model) is a model that represents the behavior of the moving body 1 in the roll direction using two mass points 61, 62 (first mass point 61 and second mass point 62), as shown in Fig. 3. The XYZ coordinate system shown in Fig. 3 is the same as the three-axis Cartesian coordinate system shown in Fig. 1. In the following explanation, the front-to-rear direction of the vehicle body 2 is referred to as the X-axis direction, and the left-to-right direction is referred to as the Y-axis direction.

[0061] In this two-mass model, the first mass 61 is an inverted pendulum mass that can move in the Y-axis direction at a certain height h' from the contact surface (horizontal plane) where the moving body 1 touches the ground via the front wheels 3f and rear wheels 3r, and the second mass 62 is a mass that can move in the Y-axis direction on the contact surface.

[0062] The relationship between the masses m1 and m2 of the first mass point 61 and the second mass point 62, the total mass m of the moving body 1, the height h of the total center of gravity G of the moving body 1, and the inertia Ix of the moving body 1 around the total center of gravity G (more specifically, around the axis in the X-axis direction passing through the total center of gravity G) is defined by the following equations (1a), (1b), and (1c). m1+m2=m ……(1a) m1·(h-h')=m2·h ……(1b) m1·(h-h') 2 +m2·h 2 =Ix ……(1c)

[0063] Furthermore, the state equation for the displacement P1y of the first mass point 61 in the Y-axis direction (hereinafter referred to as lateral displacement P1y) when the body 2 of the moving body 1 tilts in the roll direction from a straight-ahead posture state is expressed by the following equation (2): In the following explanation, for an arbitrary state quantity A, A_dot represents the time rate of change of A (time differential value).

[0064]

number

[0065] Here, ωn is the natural frequency of the two-mass model, g is the gravitational acceleration (constant), Vox is the movement speed of the overall center of gravity G of moving body 1 in the X-axis direction (= running speed of moving body 1), Voy is the movement speed of the overall center of gravity G of moving body 1 in the Y-axis direction (lateral movement speed of moving body 1), and ωz is the yaw rate of moving body 1 around the overall center of gravity G (angular velocity around the vertical axis passing through the overall center of gravity G).

[0066] 3, Φ' is the tilt angle of the first mass point 61, which is the inverted pendulum mass point. Also, with reference to FIGS. 1A, 1B, and 3B, Φb is the tilt angle of the rear wheels 3r with respect to the vehicle body 2, δf is the steering angle of the front wheels 3f (the rotation angle about the front-wheel steering axis Cf), δr is the tilt angle of the rear wheels 3r with respect to the vehicle body 2 (the rotation angle about the rear-wheel steering axis Cr), θcf is the caster angle of the front-wheel steering axis Cf, and θcr is the caster angle of the rear-wheel steering axis Cr. The positive directions of Φb, δf, and δr correspond to the directions of the arrows shown in FIG. 1A or 1B, respectively.

[0067] L is the wheelbase of the moving body 1 (the distance between the ground contact point of the front wheel 3f and the ground contact point of the rear wheel 3r of the moving body 1 in a straight-ahead driving posture), Lf is the distance in the X-axis direction between the center of gravity G of the entire moving body 1 in a straight-ahead driving posture and the ground contact point of the front wheel 3f, Lr is the distance in the X-axis direction between the center of gravity G of the entire moving body 1 in a straight-ahead driving posture and the ground contact point of the rear wheel 3r, af is the height from the ground contact surface of the intersection of the vertical axis passing through the axle center of the front wheel 3f and the front-wheel steering axis Csf when the moving body 1 in a straight-ahead driving posture is projected onto a plane perpendicular to the Y-axis, and ar is the height from the ground contact surface of the intersection of the vertical axis passing through the axle center of the rear wheel 3r and the rear-wheel steering axis Csr when the moving body 1 in a straight-ahead driving posture is projected onto a plane perpendicular to the Y-axis.

[0068] Lof is the distance between the axle center of the front wheel 3f and the front-wheel steering axis Cf when the mobile body 1 in a straight-ahead driving posture is projected onto a plane perpendicular to the Y axis, and Lor is the distance between the axle center of the rear wheel 3r and the rear-wheel steering axis Cr when the mobile body 1 in a straight-ahead driving posture is projected onto a plane perpendicular to the Y axis. In addition, in equation (2-4), an approximation that tanΦ'≒Φ' is used. In equations (2-8) and (2-9), the influence of the sideslip angle of the moving object 1 is ignored.

[0069] As can be seen from equation (2-7) and the other equations (2-1) to (2-6), (2-8) to (2-13), the input p (control input) for controlling the lateral movement amount P1y is a function of the traveling speed Vox of the moving body 1, the steering angle δf of the front wheels 3f, and the tilt angle δr of the rear wheels 3r.

[0070] In the posture stabilization control, the control device 40 determines the control input p in the formula (2) within the range between its lower limit value pL and upper limit value pH as shown in the following formulas (3a) to (3c). When pL ≦ Kp·(P1y - P1y_cmd) + Kv·(P1y_dot - P1y_dot_cmd) ≦ pH, p = Kp·(P1y - P1y_cmd) + Kv·(P1y_dot - P1y_dot_cmd) ……(3a) However, Kv = Kp / ωn ……(4) When pL > Kp·(P1y - P1y_cmd) + Kv·(P1y_dot - P1y_dot_cmd), p = pL ……(3b) When pH < Kp·(P1y - P1y_cmd) + Kv·(P1y_dot - P1y_dot_cmd), p = pH ……(3c) Here, P1y_cmd is the target value of the lateral movement amount P1y of the first mass point 61, P1y_dot_cmd is the target value of the lateral movement speed P1y_dot of the first mass point 61, and Kp and Kv are gain coefficients.

[0071] In the situation where the control input p is determined according to the formulas (3a) and (4) as described above, the control input p can be determined so that the so-called divergence component regarding the state quantities of the control target, that is, the lateral movement amount P1y and the lateral movement speed P1y_dot of the first mass point 61, namely the divergence component ξ defined by the following formula (5), converges to zero. As a result, the lateral movement amount P1y can be stably controlled. Note that formula (3a) can be expressed as p = Kp·ξ when using the divergence component ξ. ξ = (P1y - P1y_cmd) + (P1y_dot - P1y_dot_cmd) / ωn ……(5)

[0072] In this embodiment, the control device 40 sequentially determines the control input p as described above at a predetermined control processing cycle, and determines, from the determined control input p, a rear wheel tilt angular velocity input δr_dot_stb for posture control, which is a target value of the angular velocity δr_dot of the tilt angle δr of the rear wheel 3r, as an operation amount for controlling the posture of the vehicle body 2 in the roll direction (an operation amount for converging the lateral movement amount P1y and the lateral movement velocity P1y_dot to the target values).

[0073] Here, using equations (2-1) to (2-13), the control input p in equation (2-7) is expressed by the following equation (6).

number

[0074] Based on the above equation (6), the target value δr_stb (target value δr_stab(k) at each control processing cycle) of the tilt angle δr of the rear wheel 3r for posture control can be calculated using the value p(k) of the control input p calculated from the above equation (3a) at each control processing cycle, using the following equation (7):

number

[0075] The rear wheel tilt angular velocity input δr_dot_stb(k) for posture control in each control processing cycle is determined as the differential value (=(δr_stb(k)-δr_stb(k-1)) / Δt) of the target value δr_stb of the tilt angle δr of the rear wheel 3r obtained by equation (7).

[0076] By controlling the operation of the rear-wheel tilting actuator 28 using the posture control rear-wheel tilt angular velocity input δr_dot_stb determined in this manner as a target value for the tilt angular velocity in the roll direction of the rear wheel 3r, a moment in the roll direction can be applied to the vehicle body 2 so that the lateral movement amount P1y and lateral movement velocity P1y_dot of the first mass point 61 as an inverted pendulum mass point converge to required target values. As a result, the posture of the vehicle body 2 can be automatically stabilized.

[0077] Incidentally, when the traveling speed Vox of the moving body 1 reaches a certain high speed, it is desirable for the driver of the moving body 1 to be able to control the tilt of the body 2 in accordance with the shift of his or her own weight. For this reason, in this embodiment, when the traveling speed Vox of the moving body 1 reaches a high speed equal to or greater than a predetermined value, the control device 40 stops the posture stabilization control and controls the operation of the rear wheel tilting actuator 28 so as to steadily maintain the tilt angle of the rear wheels 3r relative to the body 2 at zero.

[0078] In this case, it is desirable that the behavior of the moving object 1 can smoothly transition from a state when posture stabilization control is being executed to a state when posture stabilization control is stopped. Therefore, in this embodiment, a rear wheel tilt angular velocity command value δr_dot_cmd, which is a command value for the tilt angular velocity of the rear wheel 3r used for actual operation control of the rear wheel tilt actuator 28, is sequentially determined by the following equation (8). δr_dot_cmd=ε·δr_dot_stb+(1-ε)·Kfo·δr_act ……(8)

[0079] Here, ε is a gain coefficient that is variably set within the range of 0≦ε≦1, Kfo is a gain coefficient that is a negative value (constant), and δr_act is the actual tilt angle (detected value) of the rear wheels 3r with respect to the vehicle body 2. Supplementally, in this embodiment, the rear wheel tilt angular velocity command value δr_dot_cmd corresponds to the control input in the present invention, and δr_dot_stb and Kfo·δr_act on the right side of equation (6) correspond to the first control input component and the second control input component, respectively, in the present invention. ε corresponds to the first gain coefficient, and (1−ε) corresponds to the second gain coefficient.

[0080] As shown in FIG. 5, the gain coefficient ε is basically set according to the traveling speed Vox (detected value) so as to change from "1" to "0" as the traveling speed Vox of the moving object 1 increases.

[0081] In this case, when the moving body 1 is stopped or traveling at a low speed, and ε is set to “1”, equation (8) becomes δr_dot_cmd=δr_dot_stb, so a moment in the roll direction is applied to the body 2 so that the lateral movement amount P1x of the first mass point 61 converges to the required target value, thereby automatically stabilizing the posture of the body 2.

[0082] Furthermore, when the moving body 1 is traveling at high speed and ε is set to "0," equation (8) becomes δr_dot_cmd=Kfo·δr_act, and therefore the rear wheel tilt angular velocity command value δr_dot_cmd is determined so as to cause the actual tilt angle δr_act of the rear wheels 3r to converge to "0." This stops the tilting of the rear wheels 3r relative to the vehicle body 2, allowing the driver to tilt the vehicle body 2 to a desired tilt state by shifting his or her own weight.

[0083] Supplementally, by Laplace transforming the above equation (8), the following equation (9) is obtained:

number

[0084] Equation (9) indicates that the tilt angle δr of the rear wheel 3r (left side of equation (9)) controlled in accordance with the rear wheel tilt angular velocity command value δr_dot_cmd is a value obtained by filtering the tilt angle δr_stb of the rear wheel 3r due to posture stabilization control using a high-pass filter.

[0085] In posture stabilization control, if the value of the right side of equation (3a) deviates from the range between the lower limit pL and the upper limit pH, the control input p is limited to the lower limit pL or the upper limit pH, which may make it difficult to stabilize the posture of the vehicle body 2. Therefore, in this embodiment, the control device 40 adjusts the value of the gain coefficient ε so that the value of the control input p defined by equation (3a) from the pair of the lateral movement amount P1y and the lateral movement velocity P1y_dot of the first mass point 61, which are state quantities of the control object, does not become too close to the lower limit pL or the upper limit pH. Therefore, in this embodiment, the gain coefficient ε is variably set in accordance with the traveling speed Vox, and is also set so that the value of the control input p defined by equation (3a) does not become too close to the lower limit pL or the upper limit pH. The process of setting the gain coefficient ε in this way (in other words, the process of setting the gain coefficient ε and the gain coefficient (1−ε)) is performed as described below.

[0086] (STEP 1) The control device 40 uses the maximum moment specifying unit 41 to specify the maximum roll moment that can act on the vehicle body 2. In this case, the specified maximum roll moments are the negative maximum roll moment (the maximum value of the moment in the counterclockwise direction as seen from the rear of the vehicle body 2) and the positive maximum roll moment (the maximum value of the moment in the clockwise direction as seen from the rear of the vehicle body 2), and these maximum roll moments are determined as function values ​​of the maximum values ​​of the steering angle δf of the front wheels 3f (the maximum value on the positive side and the maximum value on the negative side) and the maximum values ​​of the tilt angle δr of the rear wheels 3r (the maximum value on the positive side and the maximum value on the negative side).

[0087] That is, the maximum moment identification unit 41 calculates the upper limit value pH (maximum positive value) and the lower limit value pL (maximum negative value) of the control input p based on the equations (2-1) to (2-13) using the current traveling speed Vox of the moving body 1, the maximum value of the steering angle δf of the front wheels 3f (maximum positive value and maximum negative value), and the maximum value of the tilt angle δr of the rear wheels 3r (maximum positive value and maximum negative value).

[0088] The maximum moment specifying unit 41 then calculates m1·h'·ωn for the upper limit value pH (maximum value on the positive side) and the lower limit value pL (maximum value on the negative side) of the control input p. 2 The maximum positive roll moment MH and the maximum negative roll moment ML are determined by multiplying the above values ​​by 1 / 2.

[0089] (STEP 2) Next, the control device 40 uses the limit state quantity identification unit 42 to identify the limit state quantity (limit state quantity related to the roll direction posture of the vehicle body 2) that can cause the lateral movement amount P1y and lateral movement velocity P1y_dot of the first mass point 61 to converge to the target value when the maximum roll moments ML and MH are applied to the vehicle body 2.

[0090] In this embodiment, the value of the divergence component ξ related to the motion of the first mass point 61 as an inverted pendulum mass point is used as the limit state quantity. In this case, the value of the divergence component as the limit state quantity includes a small limit value ξL and a large limit value ξH (>ξL), which are calculated from the negative maximum roll moment ML and the positive maximum roll moment MH by the following equations (10a) and (10b), respectively. ξL=ML / (m1·h'·ωn 2 ) / Kp ……(10a) ξH=MH / (m1·h'·ωn 2 ) / Kp ……(10b)

[0091] (STEP 3) Next, the control device 40, via the attitude stability index value determiner 43, determines an attitude stability index value FDR that indicates a stability margin (stability allowance) for the attitude of the vehicle body 2 in the roll direction. In this embodiment, the attitude stability index value FDR is an index value that is determined by the following equation (11) from the current value ξ(t) of the divergence component ξ, which is calculated by the following equation (11a) corresponding to the current values ​​P1y(t) and P1y_dot(t) of the lateral movement amount P1y and lateral movement velocity P1y_dot of the first mass point 61, and the limit value ξlim (ξL or ξH) of the small side limit value ξL and the large side limit value ξH determined in STEP 2, which is closer to the current value ξ(t). The attitude stability index value FDR indicates the amount of deviation of the current value ξ(t) of the divergence component ξ from the limit value ξlim (ξL or ξH). FDR=|ξ (t)| / |ξlim| ……(11) however, ξ(t)=(P1y(t)-P1y_cmd)+(P1y_dot(t)-P1y_dot_cmd) / ωn ……(11a) ξlim: The limit value of ξL or ξH, whichever is closer to ξ(t)

[0092] The current value P1y(t) of the lateral movement amount P1y is calculated based on the above equations (2-4) to (2-6). The current value P1y_dot(t) of the lateral movement speed P1y_dot is calculated as a pseudo-differential value of the lateral movement amount P1y.

[0093] Referring to FIG. 4, on a coordinate plane having the lateral movement amount P1y and the lateral movement speed P1y_dott as two coordinate axis components, a set (P1y, P1y_dot) of the lateral movement amount P1y and the lateral movement speed P1y_dot is expressed by the equation (P1y-P1y_cmd)+(P1y_dot-P1y_dot_cmd) / ωn=ξL, and a set (P1y, P1y_dot) of the lateral movement amount P1y and the lateral movement speed P1y_dot is expressed by the equation (P1y-P1y_cmd)+(P1y_dot-P1y_dot_cmd) / ωn=ξL. By controlling the lateral movement amount P1y so that it falls within the range between the line L1 and L2 expressed by the equation ωn=ξH (in other words, by controlling the lateral movement amount P1y so that the value ξ(t) of the divergence component ξ expressed by equation (8a) falls within the range between ξL and ξH), it is possible to stably converge (P1y, P1y_dot) to the target values ​​(P1y_cmd, P1y_dot_cmd), and ultimately to stabilize the posture of the vehicle body 2. Therefore, it is preferable to control the lateral movement amount P1y so that (P1y, P1y_dot) falls within the range between the lines L1 and L2, and does not come too close to L1, L2.

[0094] Furthermore, when the value of the attitude stability index value FDR defined by equation (9) is smaller than "1", (P1y, P1y_dot) falls between lines L1 and L2, and when the value of the attitude stability index value FDR is greater than "1", (P1y, P1y_dot) deviates from between lines L1 and L2. In a state where FDR<1, the closer the value of the attitude stability index value FDR is to "0", the further away (P1y, P1y_dot) is from lines L1 and L2. Therefore, the closer the attitude stability index value FDR is to "0", the higher the stability margin of the attitude of the vehicle body 2, and the attitude stability index value FDR can function as an index value representing the stability margin of the attitude.

[0095] (STEP 4) After the control device 40 determines the posture stability index value FDR using the posture stability index value determination unit 43 as described above, the control gain adjustment unit 44 then determines the value of the gain coefficient ε from the current value of the traveling speed Vox of the moving body 1 and the value of the posture stability index value FDR.

[0096] In this case, the relationship between the pair of traveling speed Vox and posture stability index value FDR and the gain coefficient ε is determined in advance in the form of a map or an arithmetic expression, as shown in Fig. 5. Therefore, when the posture stability index value FDR is equal to or greater than "1", the gain coefficient ε is set to its maximum value of "1". On the other hand, when the posture stability index value FDR is smaller than "1", the gain coefficient ε is set to decrease from "1" as the traveling speed Vox increases, and to decrease from "1" to "0" as the posture stability index value FDR approaches "0".

[0097] Therefore, when the stability margin of the posture of the vehicle body 2 is high (when the posture stability index value FDR is close to "0"), the gain coefficient ε is set to "0" or a value close to "0" except when the traveling speed Vox is low, and when the stability margin of the posture of the vehicle body 2 is low (when the posture stability index value FDR is close to "1" or greater than "1") or when the traveling speed Vox is low, the gain coefficient ε is set to "1" or a value close to "1".

[0098] According to the embodiment described above, the value of the gain coefficient ε serving as the control gain in the posture stabilization control in the roll direction of the vehicle body 2 is determined in accordance with the posture stability index value FDR as described above, and therefore the tilt angle in the roll direction of the vehicle body 2 can be controlled so that the value of the divergence component ξ related to the motion of the first mass point P1y as an inverted pendulum mass point does not become too close to the small limit value ξL or the large limit value ξH.

[0099] In this case, when the attitude stability index value FDR is close to zero (when the stability margin of the attitude of the vehicle body 2 is high) or when the traveling speed Vox of the moving object 1 is in the high speed range, the gain coefficient ε is set to zero or a value close to zero, and therefore the attitude stabilization control is stopped or weakened. Therefore, the driver can easily change the attitude of the vehicle body 2 in the roll direction by shifting his or her own weight.

[0100] Furthermore, when the attitude stability index value FDR is close to "1" (the attitude stability margin of the vehicle body 2 is low) or when the traveling speed Vox of the moving body 1 is in the low speed range (including when the vehicle is stopped), the gain coefficient ε is set to "1" or a value close to "1", thereby strengthening the attitude stabilization control. As a result, the attitude of the vehicle body 2 in the roll direction can be automatically maintained stable. Therefore, it is possible to appropriately ensure stability in the posture of the vehicle body 2 in the roll direction and to improve the maneuverability of the moving body 1 by the driver.

[0101] The gain coefficient ε is set as described above in accordance with the posture stability index value FDR and the traveling speed Vox, and the rear wheel tilt angular velocity command value δr_dot_cmd for actual tilt control of the rear wheels 3r is determined using this gain coefficient ε according to the above equation (8). This allows for a smooth transition between a state in which the rear wheels 3r are tilted relative to the vehicle body 2 and a state in which the tilt of the rear wheels 3r relative to the vehicle body 2 is stopped.

[0102] The present invention is not limited to the above-described embodiment, and other embodiments may be adopted. Some other embodiments are exemplified below. In the above embodiment, the index value defined by equation (11) is used as the attitude stability index value FDR indicating the stability margin of the attitude of the vehicle body 2 in the roll direction. However, other index values ​​may also be used as the attitude stability index value FDR. For example, with reference to Fig. 4, when the distance between the point of the current value (P1y(t).P1y_dot(t)) and one of lines L1 and L2 that is closer to the current value (P1y(t).P1y_dot(t)) (in Fig. 4, line L2 corresponding to the large limit value ξH) is denoted as d(t), and the distance between the point of the target value (P1y_cmg.P1y_dot_cmd) and the line that is closer to the current value (P1y(t).P1y_dot(t)) (in Fig. 4, line L2) is denoted as dlim, an index value defined by the following equation (12) may be used as the attitude stability index value FDR. FDR = d(t) / dlim ……(12)

[0103] In addition, in the above embodiment, the mechanism described in Patent Document 1 is used as the rear wheel support mechanism 20 for tilting the rear wheels 3r in the roll direction relative to the vehicle body 2, but the rear wheel support mechanism 20 may be a mechanism of another structure. For example, the rear wheel support mechanism 20 may be the mechanism described in Patent Document 2 (a mechanism having a guide rail).

[0104] Furthermore, in the above embodiment, the limit values ​​ξL, ξR of the divergence component ξ corresponding to the set of the lateral movement amount P1y and lateral movement velocity P1y_dot of the first mass point 61 (inverted pendulum mass point) were used as the limit state quantity according to the maximum roll moment. However, as the limit state quantity, for example, a set of respective limit values ​​of the lateral movement amount P1y and lateral movement velocity P1y_dot (respective limit values ​​of the lateral movement amount P1y and lateral movement velocity P1y_dot that can approach the target values ​​by the maximum roll moment) may be exploratoryally identified.

[0105] In this case, the posture stability index value can be, for example, a ratio obtained by dividing the distance D(t) between the point corresponding to the set of current values ​​of the lateral movement amount P1y and the lateral movement speed P1y_dot and the point corresponding to the set of their respective limit values ​​by the distance Dlim between the point corresponding to the set of target values ​​of the lateral movement amount P1y and the lateral movement speed P1y_dot and the point corresponding to the set of their respective limit values.

[0106] Furthermore, in the above embodiment, the state quantities of the control object in the posture stabilization control of the vehicle body 2 are a set of the lateral movement amount P1y and the lateral movement velocity P1y_dot of the first mass point 61 (inverted pendulum mass point) of the two-mass point model, but, for example, instead of the set of the lateral movement amount P1y and the lateral movement velocity P1y_dot, the state quantities of the control object may be a set of the tilt angle Φb and the tilt angular velocity Φb_dot of the vehicle body 2. In this case, for example, by executing a process in which the lateral movement amount P1y and the lateral movement velocity P1y_dot are replaced with the tilt angle Φb and the tilt angular velocity Φb_dot of the vehicle body 2, in the posture stabilization control process described in the above embodiment, it is possible to perform posture stabilization control similar to the above embodiment.

[0107] In addition, in the above embodiment, the value of the gain coefficient ε is changed according to the posture stability index value FDR, which indicates the stability margin of the posture of the vehicle body 2. However, the value of the gain coefficient ε may be set not to change according to the posture stability index value FDR. In this case, it is also possible to control the tilting of the rear wheel 3r relative to the vehicle body 2 without reflecting the stability margin of the posture of the vehicle body 2. Alternatively, for example, the value of the gain coefficient Kp in the above equation (3a) may be changed according to the posture stability index value FDR (the closer FDR is to zero, the smaller the magnitude of the gain coefficient Kp).

[0108] In addition, in the moving body 1 of the above embodiment, the front wheels 3f are steering wheels and the rear wheels 3t are tilting wheels, but the moving body may be configured so that the rear wheels are steering wheels and the front wheels are tilting wheels. Then, by tilting the front wheels in the roll direction, the posture of the vehicle body in the roll direction may be stabilized. [Explanation of symbols]

[0109] 1...moving body, 2...vehicle body, 3f...front wheels (moving operation unit), 3r...rear wheels (moving operation unit), 28...rear wheel tilting actuator (actuator), 40...control device, 41...maximum moment specifying unit, 42...limit state quantity specifying unit, 43...posture stability index value determining unit, 44...control gain adjusting unit.

Claims

1. A mobile body having a vehicle body with a driver's seat and capable of tilting in a roll direction relative to a road surface, front wheels and rear wheels arranged at an interval in the front-rear direction of the vehicle body, an actuator capable of applying a moment in the roll direction to the vehicle body, and a control device having a function of controlling the actuator so as to stabilize the posture of the vehicle body in the roll direction, one of the front wheels and the rear wheels is a steering wheel, and the other wheel is a tilting wheel mounted on the vehicle body so as to be tiltable in a roll direction relative to the vehicle body, the actuator is configured to tilt the tilting wheel in a roll direction relative to the vehicle body, thereby applying a moment in the roll direction to the vehicle body, the control device is configured to determine a control input for manipulating the tilting of the tilting wheel relative to the vehicle body by a linear combination of a first control input component that stabilizes the posture of the vehicle body in the roll direction and a second control input component that causes the tilt angle of the tilting wheel relative to the vehicle body to converge to zero, and to control the actuator in accordance with the determined control input, and is configured to variably set a first gain coefficient related to the first control input component and a second gain coefficient related to the second control input component in the linear combination so that as the value of one of the first gain coefficient and the second gain coefficient increases, the value of the other decreases.

2. 2. The moving body according to claim 1, The control device is configured to set the values ​​of the first gain coefficient and the second gain coefficient so that the sum of the first gain coefficient and the second gain coefficient becomes a predetermined value.

3. 2. The moving body according to claim 1, a limit state quantity specifying unit that specifies a value of a predetermined type of state quantity related to the posture of the vehicle body in the roll direction as a limit state quantity at which the posture of the vehicle body in the roll direction can be stabilized by applying the maximum moment to the vehicle body; an attitude stability index value determining unit that determines an index value representing a stability margin for the posture of the vehicle body in the roll direction from the current values ​​of the predetermined type of state quantity and the value of the limit state quantity; and a control gain adjusting unit that adjusts the values ​​of each of the first gain coefficient and the second gain coefficient in accordance with the index value.

4. 4. The moving body according to claim 3, a set of a tilt angle and a tilt angular velocity in a roll direction of the vehicle body, a function value of the tilt angle and the tilt angular velocity, a model representing a behavior of the vehicle body, the model including an inverted pendulum mass point, a set of a movement amount and a movement velocity of the inverted pendulum mass point, and a function value of the movement amount and the movement velocity.

5. 4. The moving body according to claim 3, a state quantity of a predetermined type being a value of a divergence component related to a set of a tilt angle and a tilt angular velocity in a roll direction of the vehicle body, or a value of a divergence component related to a set of a movement amount and a movement velocity of an inverted pendulum mass point in a model that represents a behavior of the vehicle body and includes the inverted pendulum mass point.

6. 4. The moving body according to claim 3, The moving body is characterized in that the index value is an index value that indicates the degree of deviation of the current value of the predetermined type of state quantity from the value of the limit state quantity.

Images