JP2008247137A - Vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle capable of reducing an inclination angle of a vehicle body corresponding to acceleration by a grounding member. <P>SOLUTION: This vehicle is an inverted vehicle. When the acceleration exceeds a prescribed threshold to be abrupt acceleration or abrupt deceleration, an auxiliary wheel is grounded. As for the acceleration, either of request acceleration and actual acceleration may be used. The grounding position of the auxiliary wheel is set to be a position away from a grounding point (reference position) of a drive wheel in the opposite direction of the acceleration as the acceleration is increased. The vehicle body is inclined at a corresponding angle in the range of prescribed acceleration, while a vehicle body inclination of a prescribed value or larger is limited by grounding the auxiliary wheel in relation to the acceleration exceeding the prescribed threshold value, and thereby comfortable acceleration/deceleration can be obtianed for an occupant. By limiting target deceleration in relation to an actual position of the auxiliary wheel, a case that large acceleration impossible to cope with is imparted before moving the auxiliary wheel is eliminated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle, for example, a vehicle using posture control of an inverted pendulum.

Vehicles that use inverted pendulum attitude control (hereinafter simply referred to as inverted pendulum vehicles) are attracting attention. In the inverted pendulum vehicle, the control unit controls the operation of the rotating body while detecting the balance state of the casing by the sensor unit, so that the conveying device is stationary or moved.
In such an inverted pendulum vehicle, Patent Documents 1 and 2 propose a technique of using a retractable auxiliary wheel as a grounding member for limiting the inclination of the vehicle body by grounding a part of the vehicle body.

Patent Document 1 describes that an auxiliary wheel is brought out and grounded when a passenger gets on and gets off, thereby stabilizing the posture of the vehicle and facilitating getting on and off of the passenger. Further, it describes that the posture of the vehicle is maintained by taking out auxiliary wheels even when the posture control is difficult.
On the other hand, Patent Document 2 describes that an auxiliary wheel is protruded at the time of abnormal operation to hold the vehicle body in a stable state.
JP 2004-74814 A JP 2004-217170 A

In an inverted vehicle, the vehicle body is tilted at the time of vehicle acceleration / deceleration, so that the balance is maintained. Therefore, if the required acceleration is large, such as sudden acceleration or sudden deceleration, the vehicle body must be largely tilted back and forth. The field of view of the vehicle greatly fluctuates, leading to a decrease in ride comfort.
However, all of the grounding members (auxiliary wheels) in the above-mentioned patent document are grounded only when the vehicle is stopped or abnormal.

  Therefore, an object of the present invention is to provide a vehicle capable of reducing a vehicle body inclination angle corresponding to acceleration by using a grounding member.

(1) In order to achieve the above object, in the first aspect of the present invention, drive wheels arranged on one axis, a vehicle body including a riding section, requested acceleration obtaining means for obtaining requested acceleration of the vehicle, By controlling the torque of the drive wheels, the vehicle body including the riding section is held in an inverted state, and travel control means that travels according to the acquired required acceleration, and the ground state and the non-ground in front or behind the drive wheels When the absolute value of the acquired requested acceleration is equal to or greater than a predetermined threshold, the grounding member is grounded on the opposite side of the direction of acceleration with respect to the drive wheel. A grounding member control means to be operated; a position acquisition means for acquiring the position of the grounded grounding member; and an absolute value of a limit acceleration corresponding to the acquired position of the grounding member is smaller than the absolute value of the acquired requested acceleration. , To provide a vehicle, characterized in that anda correction means the required acceleration to be used to modify the values of the following the limit acceleration in the running control means.
(2) In the invention described in claim 2, the grounding member control means grounds the grounding member at a position further away from the driving wheel as the absolute value of the acquired acceleration increases. A vehicle according to 1 is provided.
(3) In the invention according to claim 3, the grounding member control means has a predetermined position on the vertical line passing through the rotation axis of the drive wheel or an absolute value of the required acceleration when the grounding member is not grounded. 3. The vehicle according to claim 1, wherein the grounding member floats a predetermined distance and stands by at a grounding position in the case of a threshold value.
(4) According to the invention of claim 4, there is provided selection means for selecting a maximum value of the vehicle body inclination angle of the vehicle body, and the grounding member control means calculates an acceleration corresponding to the selected maximum value of the vehicle body inclination angle. The vehicle according to claim 1, 2, or 3, wherein the predetermined threshold value is used.
(5) In the invention according to claim 5, when the grounding member is in a grounded state, the grounding member includes slip detecting means for detecting slip of the driving wheel, and the grounding member control means is configured to detect slip of the driving wheel. The vehicle according to any one of claims 1 to 4, wherein the grounding member is moved in a direction away from the driving wheel.

  According to the present invention, when the absolute value of the required acceleration is equal to or greater than the predetermined threshold value, the grounding member is grounded on the side opposite to the direction of acceleration with respect to the driving wheel. The inclination angle can be reduced.

Hereinafter, preferred embodiments of the vehicle of the present invention will be described in detail with reference to FIGS. 1 to 11.
(1) Outline of Embodiment The vehicle of the present embodiment is an inverted vehicle, and has a structure in which a driving wheel on one axis and a riding section are connected to the axis, and the inclination of the vehicle body and the rotation of the wheel are measured by a sensor. The vehicle moves with the riding section held in an inverted state by being controlled by the drive wheel according to the measured value.
In addition, a movable auxiliary wheel mechanism that functions as a grounding member is provided. The movable auxiliary wheel mechanism includes an auxiliary wheel, a rod actuator, and a rod control ECU.
When the absolute value of acceleration exceeds a predetermined threshold during sudden acceleration / deceleration, the auxiliary wheel is grounded. As the acceleration, either requested acceleration or actual acceleration may be used. The grounding position of the auxiliary wheel is set so as to move away from the driving wheel (from the reference position) as the acceleration ahead increases from the grounding point of the driving wheel during acceleration and the rearward acceleration when decelerating.
As described above, in the vehicle of the present embodiment, the auxiliary wheel is grounded at a required position when necessary, thereby realizing both the superiority of the inverted vehicle and the superiority of the auxiliary wheel.

Specifically, when the absolute value of the acceleration is smaller than a predetermined threshold, the posture of the vehicle body is maintained by moving the center of gravity due to the vehicle body tilt.
On the other hand, when the absolute value of the acceleration is larger than the predetermined threshold, the vehicle body is inclined to the inclination angle corresponding to the predetermined threshold (maximum value of the vehicle body inclination), and the auxiliary wheel is moved and grounded in the direction opposite to the acceleration. The posture of the vehicle body is maintained by the reaction force (vertical drag force) acting on the auxiliary wheel and the movement of the center of gravity due to the vehicle body tilt.
In this way, the vehicle body tilts at a corresponding angle within a predetermined acceleration range, but the vehicle body inclination exceeding the predetermined threshold is restricted by the grounding of the auxiliary wheel for acceleration exceeding the predetermined threshold, so that it is comfortable for the passenger. Acceleration / deceleration can be realized.

  Further, when the auxiliary wheel is grounded, the position of the auxiliary wheel (wheel base between the driving wheel and the auxiliary wheel) is changed to a position at which the grounding load necessary for the driving wheel is reduced most depending on the magnitude of the acceleration. . As a result, the grounding load of the drive wheel is guaranteed, so that reliable acceleration / deceleration is realized.

In the present embodiment, since the auxiliary wheels are not grounded for acceleration / deceleration below a predetermined threshold, it is possible to reduce energy loss due to shaft friction and rotational inertia caused by unnecessary grounding of the auxiliary wheels.
The ground member is not necessarily an auxiliary wheel, and a curved member having a predetermined curvature at the tip may be grounded as a ground member.

As another embodiment, the degree of vehicle body inclination can be changed according to the preference of the passenger.
It is also possible to limit the target deceleration with respect to the actual auxiliary wheel position.
Further, when the drive wheel slips, it is possible to avoid slip by increasing the ground load of the drive wheel by moving the auxiliary wheel away.
Further, by limiting the target deceleration with respect to the actual auxiliary wheel position, it is possible to eliminate the case where a large acceleration that cannot be dealt with before the auxiliary wheel moves is eliminated.
In emergency braking, it is also possible to prioritize traveling control over vehicle body posture control. In other words, during emergency braking, the auxiliary wheels are immediately grounded while holding the vehicle upright or tilting the vehicle in the direction opposite to the acceleration direction, thereby eliminating the time delay of braking associated with the post-post-tilt operation for braking. .

(2) Details of Embodiment FIG. 1 illustrates an external configuration of a vehicle in this embodiment in a state in which an occupant is on the vehicle.
As shown in FIG. 1, the vehicle includes two drive wheels 11a (11b) arranged on the same axis. Both drive wheels 11a and 11b are driven by drive motors 12a and 12b, respectively.

Boarding on which driving bodies 11a and 11b (referred to as driving wheels 11 when referring to both driving wheels 11a and 11b; the other configurations are the same hereinafter) and driving motor 12 are loaded with heavy loads, passengers, etc. A portion 13 (sheet) is arranged.
The riding section 13 includes a seat surface section 131 on which a driver sits, a backrest section 132, and a headrest 133.
The riding section 13 is supported by a support member 14 fixed to a drive motor housing in which the drive motor 12 is housed.

An input device 30 is arranged beside the riding section 13. This input device 30 gives instructions such as acceleration, deceleration, turning, in-situ rotation, stop, braking, etc. of the vehicle by the operation of the driver.
The input device 30 in the present embodiment is fixed to the seat surface portion 131, but may be configured by a remote controller connected by wire or wirelessly. Moreover, an armrest may be provided and the input device 30 may be arranged on the upper part thereof.
Further, although the input device 30 is arranged in the vehicle of this embodiment, in the case of a vehicle that automatically travels according to predetermined travel command data, a travel command data acquisition unit is arranged instead of the input device 30. Established. For example, the travel command data acquisition unit includes a reading unit that reads the travel command data from various storage media such as a semiconductor memory, and / or a communication control unit that acquires the travel command data from the outside through wireless communication. It may be.

In FIG. 1, the boarding unit 13 displays a case where a person is on board. However, the boarding part 13 is not necessarily limited to a vehicle driven by a person, and only a baggage is placed and the vehicle is driven by an external remote control operation or the like. In the case where the vehicle is stopped or stopped, only the baggage is loaded and the vehicle is driven or stopped in accordance with the driving command data. Further, the vehicle may be driven or stopped while nothing is on board.
In the present embodiment, control such as acceleration / deceleration is performed by an operation signal output by operating the input device 30.

  A control unit (not shown) is disposed between the riding section 13 and the drive wheel 11. In the present embodiment, a control unit is attached to the lower surface of the seat surface portion 131.

In addition, a movable auxiliary wheel mechanism is disposed on the seat surface portion 131.
The movable auxiliary wheel mechanism includes an auxiliary wheel 15, a rod actuator F62, and a rod actuator R63.
As shown in FIG. 1A, one end 62a of the rod actuator F62 is disposed in front of the seat portion 131, and the other end 62b is arranged coaxially with the rotation axis of the auxiliary wheel 15. It is installed.
One end 63a of the rod actuator R63 is disposed behind the seat portion 131, and the other end 63b is disposed coaxially with the rotation shaft of the auxiliary wheel 15.
Both ends of the rod actuator F62 and the rod actuator R63 are rotatably attached to the seat surface portion 131 and the auxiliary wheel 15.
Note that the one ends 62a and 63a of the rod actuators F62 and R63 may be pivotally attached to other parts of the vehicle body, for example, the support member 14, instead of the seat surface portion 131.

Both rod actuators F62 and R63 have a structure in which the entire length changes by expanding and contracting.
FIG. 1A shows a reference state, that is, a state in which the auxiliary wheel 15 is directly below the drive shaft of the drive wheel 11 when the vehicle body is in an upright posture.
On the other hand, FIG. 1B shows the inclination of the vehicle body and the state of the double rod actuators F62 and R63 during deceleration.
As shown in FIG. 1 (b), when the absolute value of acceleration is equal to or greater than a predetermined threshold, the vehicle body is moved backward to an inclination angle (maximum inclination angle) corresponding to the predetermined threshold as shown in FIG. 1 (b). And the auxiliary wheel is grounded at a distance corresponding to the acceleration in the forward direction (in the direction opposite to the acceleration) with respect to the driving wheel. The normal force counteracts the inertial force that accompanies acceleration / deceleration and the anti-torque action of the drive wheels, maintaining the balance of the vehicle body.
In this state, by extending the rear rod actuator R63 longer than the front rod actuator F62, the auxiliary wheel is grounded at a predetermined distance from the front. Thus, by adjusting the expansion / contraction amount of both rod actuators F62 and R63, the auxiliary wheel can be grounded at an arbitrary position.

  Further, by slightly contracting both rod actuators F62 and R63 while the auxiliary wheel 15 is in contact with an arbitrary position, it is possible to slightly lift the auxiliary wheel at that position and wait in a non-contact state.

FIG. 2 shows the configuration of the control unit.
The control unit includes a control ECU (electronic control device) 20, an acceleration / deceleration command device 31, an angle meter (angular velocity meter) 41, a drive wheel rotation angle meter 51, a drive wheel actuator 52 (drive motor 12), and a rod drive motor rotation angle meter. (Extension / contraction sensor) 61, rod actuators F62 and R63, and other devices are provided.

  The control unit includes a battery (not shown) as another device. The battery supplies power for driving and calculation to the drive motor 12, the drive actuator 52, the double rod actuators F62 and R63, the control ECU 20, and the like.

The control ECU 20 includes a main control ECU 21, a drive wheel control ECU 22, and a rod control ECU 23, and performs various controls such as vehicle travel and attitude control by drive wheel control, vehicle body control (inversion control), and the like. Yes. Further, the control ECU 20 performs posture control using the auxiliary wheels 15 during acceleration / deceleration in the present embodiment.
The control ECU 20 is configured by a computer system including a ROM that stores various programs and data, a RAM that is used as a work area, an external storage device, an interface unit, and the like.

The main control ECU 21 is connected to a drive wheel rotation angle meter 51, an angle meter (angular velocity meter) 41, a rod drive motor rotation angle meter 61, and an acceleration / deceleration command device 31 as an input device 30.
The acceleration / deceleration command device 31 is composed of a joystick, for example, and supplies a travel command based on the operation of the passenger to the main control ECU 21. The joystick is set to a neutral position in an upright state, instructing acceleration by inclining in the front-rear direction, and instructing turning curvature by inclining left and right. When the inclination angle is increased, the required acceleration / deceleration and the turning curvature increase.

  The main control ECU 21 functions as the vehicle body control system 40 together with the goniometer 41, and performs vehicle body posture control with the counter torque of the drive motor 12 based on the vehicle body tilt state as posture control of the inverted vehicle.

The main control ECU 21 functions as the drive wheel control system 50 together with the drive wheel control ECU 22, the drive wheel rotation angle meter 50, and the drive wheel actuator 52.
The drive wheel rotation angle meter 51 supplies the rotation angle of the drive wheel 11 to the main control ECU 21, the main control ECU 21 supplies a drive torque command value to the drive wheel control ECU 22, and the drive wheel control ECU 22 supplies the drive wheel actuator 52 to the drive wheel actuator 52. A drive voltage corresponding to the drive command value is supplied.
The drive wheel motion actuator 52 controls both the drive wheels 11a and 11b independently according to the command value.
The main control ECU 21 functions as drive wheel torque determination means.

The main control ECU 21 functions as a rod control system 60 (grounding member control means) together with the rod control ECU 23, the rod drive motor rotation angle meter (expansion / contraction amount sensor) 61, and rod actuators F62 and R63.
The rod drive motor rotation angle meter 61 supplies the rotation angle of the rod drive motor, that is, the expansion / contraction amounts λ _F and λ _R of both rod actuators, to the main control ECU 21, and the main control ECU 21 sends a drive thrust command value to the rod control ECU 23. The rod control CU23 supplies a drive voltage corresponding to the drive thrust command value to each of the rod actuators F62 and R63.
Both rod actuators F62 and R63 expand and contract according to the command value, thereby realizing movement of the auxiliary wheel 15 to a predetermined position and switching between grounding and non-grounding.

The auxiliary wheel control according to the acceleration in the vehicle of the present embodiment configured as described above will be described.
The acceleration required from the input device may be positive (acceleration) or negative (deceleration). However, both control are the same by reversing the direction. The case where the acceleration is a negative value, that is, the case of deceleration will be described as an example.
FIG. 3 shows a dynamic model of the vehicle attitude control system in the present embodiment.
The symbols in FIG. 3 are as follows, and the symbols in the following embodiments use symbols corresponding to this dynamic model.
(A) State quantity θ _W : Drive wheel rotation angle [rad]
θ ₁ : tilt angle of main body (vertical axis reference) [rad]
b: Distance between driving wheel and auxiliary wheel contact point (wheel base) [m]
λ _F : Expansion amount of rod actuator F λ _R : Expansion amount of rod actuator R (b) input τ _W : Drive motor torque (total of two wheels) [Nm]
T _F : Thrust of rod actuator F [N]
T _R : Thrust of rod actuator R [N]
(C) Physical constant g: Gravitational acceleration [m / s ² ]
(D) Parameter m _W : Mass of drive wheel [kg]
R _W : radius of drive wheel [m]
I _W : Moment of inertia of drive wheel (around axle) [kgm ² ]
r _W : radius of auxiliary wheel [m]
m ₁ : Mass of the main body (including passengers) [kg]
l ₁ : Distance from the center of gravity of the main unit (from the axle) [m]
I ₁ : Moment of inertia of body (around center of gravity) [kgm ² ]

FIG. 4 is a flowchart showing the deceleration traveling control process in the first embodiment.
The main control ECU 21 acquires each state quantity from the sensor (step 1). That is, the main control ECU 21 determines the drive wheel rotation angle θ _W from the drive wheel rotation angle meter 51, the vehicle body inclination angle θ ₁ (angular velocity) from the angle meter (angular velocity meter) 41, and the rod drive motor rotation angle meter (extension / contraction amount sensor). The rotation angle (expansion / contraction amounts λ _F , λ _R ) is acquired from 61.

Further, the main control ECU 21 acquires the occupant's operation amount (for example, joystick operation amount) input from the acceleration / deceleration command device 31 (step 2), and sets the deceleration target value α ^* based on the operation amount. Determine (step 3).
The target value α ^{* for} deceleration is determined to be a value proportional to the acquired operation amount, for example.

Next, the main control ECU 21 determines the target value {θ _W ^* } of the drive wheel angular speed from the target value α ^{* of} deceleration determined in step 3 (step 4).
Target value of the drive wheel angular velocity {θ _W ^*}, for example, converts the acceleration to the speed by integrating the target value of the deceleration alpha ^* time and this divided a predetermined drive wheel ground contact radius R _W value Is used.
In this specification, the symbol {X} represents the time derivative of X.

Next, the main control ECU 21 determines the target value θ ₁ ^* of the vehicle body tilt angle from Expression 1, and determines the target value b ^* of the auxiliary wheel position from Expression 2 (Step 5).
That is, the main control ECU 21 determines the target value θ ₁ ^* of the vehicle body tilt angle and the target value b ^* of the auxiliary wheel position necessary for realizing deceleration at the deceleration target value α ^* determined in step 3. .

(Formula 1)
When α ^* <α _Max θ ₁ ^* = φ ^* + sin ^-1 (tanγsinφ ^* )
When α ^* ≧ α _Max θ ₁ ^* = θ _{1, Max}

(Formula 2)
When α ^* <α _Max b ^* = 0
When α ^* ≧ α _Max b ^* = C _safe b ₀ ^*

In Equation 1, φ ^* is the equilibrium axis tilt angle, and is given by φ ^* = tan ⁻¹ α ^* . As the deceleration target α ^* increases, φ ^* increases.
In Equation 2, b ₀ ^* is the slip limit auxiliary wheel position and is a function of the deceleration target α ^* .
As the deceleration target α ^* increases, b ₀ ^* increases (see Equation 2-2 described later).
FIG. 5 shows the relationship between the target value θ ₁ ^* of the vehicle body inclination angle and the target value b ^* of the auxiliary wheel position (Formula 1 and Formula 2) with respect to the deceleration target value α ^* determined in Step 3. It is.
5 and as expressed in Equation 1, the target value theta ₁ ^* is the vehicle body tilt angle, when the target value of the deceleration alpha ^* is less than the threshold value alpha _Max is the maximum vehicle body with increasing target value alpha ^* two Increases to tilt angle θ _{1, Max} (set value). On the other hand, when the target value α ^* is greater than or equal to the threshold value α _{Max, the} maximum vehicle body inclination angle θ _{1, Max} is always set _, and the vehicle body is determined not to tilt further.

As shown in FIG. 5 and Formula 2, when the deceleration target value α ^* is less than the threshold value α _Max , the auxiliary wheel position target value b ^* is determined to be zero.
When the target value α ^* is equal to or greater than the threshold value α _Max , the target value b ^* of the auxiliary wheel position increases with the target value α ^* .

In this way, when the deceleration target value α ^* is less than the threshold α _Max , the vehicle body is tilted within the range of the maximum vehicle body inclination angle θ _{1, Max} , and the balance of the vehicle body during deceleration is achieved by moving the center of gravity due to the vehicle body inclination. keep. In this range, the auxiliary wheel 15 is not grounded, unnecessary grounding of the auxiliary wheel 15 is eliminated, and energy loss due to grounding of the auxiliary wheel 15 can be reduced.
On the other hand, when the target value α ^{* of} deceleration is equal to or greater than the threshold value α _Max , the target value θ ₁ ^* of the vehicle body inclination angle is held at the maximum vehicle body inclination angle θ _{1, Max} . Only the movement of the center of gravity due to the tilt of the vehicle body does not maintain the balance of the vehicle body at the time of deceleration, and the vehicle body is tilted forward, so that the insufficient tilt torque is compensated by the vertical drag of the grounding point of the auxiliary wheel 15 thereafter.
Then, the target value b ^* of the auxiliary wheel position to increase with the target value of the deceleration alpha ^*, wheelbase b is set according to the target value alpha ^*. This prevents the vehicle body from leaning forward when the target deceleration rate α ^* is large, or slipping due to a decrease in the ground load on the drive wheels.

In Equations 1 and 2, the threshold value α _Max is determined by the predetermined maximum vehicle body inclination angle θ _{1, Max} from Equation 1-2 below. In Equation 2, tanγ is determined by Equation 1-3, and M in Equation 1-3 is determined by Equation 1-4.

(Formula 1-2)
α _Max = (sin θ _{1, Max} ) / (cos θ _{1, Max} + tan γ)
(Formula 1-3)
tanγ = (MR _W ) / (m ₁ l ₁ )
(Formula 1-4)
M = m ₁ + m _W + I _W / R _W ²

In Equation 2, b ₀ ^* is the auxiliary wheel position at the slip limit and is expressed by Equation 2-2. M _b ^* is expressed by Formula 2-3.
In this way, by giving the safety coefficient C _safe to the auxiliary wheel position b ₀ ^* at the slip limit, the idling of the driving wheel is suppressed and the safety is ensured. The slip limit is determined by the coefficient of static friction μ between the drive wheel and the road surface (predetermined predicted value). The safety coefficient C _safe is a predetermined set value.

(Formula 2-2)
^{_{b 0 * = l 1 (m}} 1 / M b *) (tanγsinφ * + sin (φ * -θ 1, Max)) / cosφ *
(Formula 2-3)
M _b ^* = (1− (α ^* / μ)) M

Next, the main control ECU 21 moves the auxiliary wheel 15 to the target value b ^* of the auxiliary wheel position determined by Formula 2, and in accordance with that value, the target value λ _F of the rod expansion / contraction amount for the rod actuators F62 and R63. ^{* And} λ _R ^* are determined by the following Equation 3 (step 6).
In Expression 3, ε is determined by Expression 3-2 and λ ₀ is determined by Expression 3-3.

(Formula 3)
λ _F ^* = √ ((d cos θ _{1, Max−} h sin θ _{1, Max} −b ^* ) ² + (h cos θ _{1, Max} + d sin θ _{1, Max} + R _W −r _W + ε) ² ) −l ₀
λ _R ^* = √ ((d cos θ _{1, Max} + h sin θ _{1, Max} + b ^* ) ² + (h cos θ _{1, Max} −d sin θ _{1, Max} + R _W −r _W + ε) ² ) −l ₀

(Formula 3-2)
When b ^* = 0, ε = −δ
When b ^* > 0, ε = 0

(Formula 3-3)
l ₀ = √ (d ² + (h + R _W −r _W ) ² )

In Expression 3-2, δ is a minute shortening amount for lifting the auxiliary wheel 15 from the contact surface.
That is, when the deceleration target value α ^* <threshold α _Max (b ^* = 0), from Equation 3, the auxiliary wheel 15 stands by in a non-grounded state at a position δ immediately above the grounding position closest to the driving wheel 11. Will do.

The shortening amount δ in the present embodiment is arbitrary, but is set to 5 mm, 1 cm, or the like, for example.
For the shortening amount δ, for example, a different value may be used depending on the state of a road such as a paved road and an unpaved road. In this case, the state of the road is determined from the vibration state detected by the vibration sensor. Alternatively, the amplitude of vibration may be detected, and the shortening amount δ may be changed according to the amplitude. In addition, the corresponding shortening amount δ may be adopted by the passenger inputting a paved road or an unpaved road.

In Expression 3-3, l ₀ is a reference length of the both rod actuators F62 and R63. The state in which the auxiliary wheel 15 is in contact with the drive wheel 11 directly below the drive shaft when the vehicle body is in the upright posture is defined as a reference state, and the total length of the rod in this reference state is defined as a reference length l ₀ .
A difference from the reference length l ₀ is defined as a rod expansion / contraction amount λ.
Further, d is a value when the distance between the end portions (fixed points) 62a and 63a on the riding section 13 side of the rod actuators F62 and R63 is 2d.
h is the distance from the intermediate point between the two fixed points 62a and 63a to the rotation center of the drive wheel 11.

In addition, the structure of the rod actuators F62 and R63 in the present embodiment is an example of an auxiliary wheel position control mechanism, and another mechanism can be employed. For example, one end of the rod actuator may be attached to the vehicle body such as the seat portion 131, and the grounding, non-grounding, and grounding position of the auxiliary wheel 15 may be changed by adjusting the angle and expansion / contraction amount of the rod with a drive motor. Good.
In this case, a target value corresponding to the structure is set instead of Equation 3.

Next, the main control ECU 21 determines an output command value for each actuator (step 7). That is, the main control ECU 21 determines the torque command value τ _W of the drive wheel 11 from Formula 4 and determines the drive thrust command values T _F and T _R of both rod actuators F62 and R63 from Formula 5.
In Formula 4, the target value {θ _W ^* } of the driving wheel angular velocity determined in Step 4 and the target value θ ₁ ^* of the vehicle body tilt angle determined in Step 5 are used.
Further, in Formula 5, the target values λ _F ^* and λ _R ^* of the rod expansion / contraction amount determined in Step 6 are used.

(Formula 4)
τ _W = −K _W2 ([θ _W ] − [θ _W ^* ]) − K _W3 (θ ₁ −θ ₁ ^* ) − K _W4 ([θ ₁ ] − [θ ₁ ^* ])

(Formula 5)
T _F = −K _L1 (λ _F −λ _F ^* ) − K _L2 ([λ _F ] − [λ _F ^* ]) − K _L3 ∫ (λ _F −λ _F ^* ) dt
T _R = −K _L1 (λ _R −λ _R ^* ) − K _L2 ([λ _R ] − [λ _R ^* ]) − K _L3 ∫ (λ _R −λ _R ^* ) dt

In Equations 4 and 5, the feedback gains K _W2 , K _W3 , K _W4 , and K _L1 , K _L2 , K _L3 are set in advance by, for example, the pole placement method.
In Formula 4, when the auxiliary wheel 15 is in contact with the ground, K _W3 = K _W4 = 0, and the inverted posture control may not be performed.
In Formula 5, the integral gain K _L3 is given to compensate for the influence of gravity and dry friction. However, input addition may be given in a feed forward manner.

The main control ECU 21 gives the determined command values to the control systems and returns to the main routine (step 8). That is, the main control ECU 21 supplies the drive wheel control ECU 22 with the torque command value τ _W of the drive wheel 11 and supplies the rod control ECU 23 with the drive thrust command values T _F and T _R of the both rod actuators F62 and R63.
As a result, the drive wheel control ECU 22 supplies the drive voltage corresponding to the command value τ _W to the drive wheel actuator 52, gives the drive torque τ _W to the drive wheel 11, and sets the target value {θ of the drive wheel angular velocity determined in step 4. _W ^* }, and feedback control is performed so that the target value θ ₁ ^* of the vehicle body inclination angle is obtained.
Further, the rod control ECU 23 supplies the drive voltages corresponding to the drive thrust command values T _F and T _R to both the rod actuators F 62 and R 63, and the target values λ _F ^* and λ _R ^{* of} the rod expansion / contraction amount determined in Step 6 ^. Feedback control is performed so that Thereby, the position of the auxiliary wheel 15 becomes the target value b ^* of the auxiliary wheel position determined in step 5.

Next, a second embodiment will be described.
In the first embodiment, the maximum vehicle body inclination angle θ _{1, Max} that determines the threshold value α _Max is a constant value preset by the designer.
On the other hand, in the second embodiment, taking into consideration that the allowable range of the vehicle body inclination by the occupant is different, the occupant can select the maximum vehicle body inclination angle θ1 _{, Max} . For example, for a passenger who wants to travel while tilting the vehicle body, the maximum vehicle body tilt angle θ _{1, Max} (threshold α _Max ) is increased to perform control so as to balance the vehicle body as much as possible. Conversely, for a passenger who wants to travel without tilting the vehicle body, control is performed to keep the posture with the auxiliary wheels 15 as much as possible by reducing the maximum vehicle body inclination angle θ _{1, Max} (threshold α _Max ). Thus, an inverted type vehicle is realized by limiting the vehicle body inclination angle according to the passenger's preference.

FIG. 6 shows the configuration of the control unit in the second embodiment.
In the control unit of the second embodiment, a vehicle body inclination command device 32 is disposed in the input device 30. The vehicle body inclination command device 32 is an input device for the passenger to specify the preference of the vehicle body inclination, and its operation amount is supplied to the main control ECU 21 as an inclination command.

FIG. 7 shows the relationship between the inclination command supplied from the vehicle body inclination command device 32 and the maximum vehicle body inclination angle θ1 _{, Max} . The main control ECU 21 has a conversion table or conversion formula corresponding to FIG. 7 in a predetermined storage unit, and determines the maximum vehicle body inclination angle θ _{1, Max} based on this.
In the present embodiment, as shown by the straight line in FIG. 7, the passenger can select any value from 0 to the maximum value as the vehicle body tilt angle. A selectable system may be used. For example, a smooth mode in which the maximum vehicle body inclination angle θ1 _{, Max} is small and a large active mode may be selectable. Further, the selection may be made in more stages. When the selection of the discrete maximum vehicle body inclination angle θ _{1, Max} is possible, the value of each maximum vehicle body inclination angle θ _{1, Max} corresponding to the selectable mode and the vehicle body inclination is stored in advance.
Other components of the control unit in the second embodiment are the same as those in the first embodiment described in FIG.

Next, the operation of the second embodiment will be described.
The main control ECU 21 monitors whether or not an inclination command value is supplied from the vehicle body inclination command device 32 by inputting the vehicle body inclination angle, separately from the deceleration traveling process in the present embodiment. When the degree command is supplied, the vehicle body tilt command value is stored in a storage unit such as a RAM.
Note that the vehicle body tilt command may be stored in a non-volatile storage unit instead of the RAM, and the vehicle body tilt command value that has been input once may be continuously used for the subsequent driving. Of course, when the occupant changes, it is possible for the occupant to newly input the vehicle body inclination angle. In this case, the data in the storage unit is updated.
The vehicle body tilt command value may be stored for each passenger by identifying the passenger. In this case, a load meter may be arranged on the seat surface portion 131 to estimate the occupant from the measured load, or the occupant himself may input his own identification data.

FIG. 8 is a flowchart showing the contents of the deceleration traveling control process in the second embodiment.
In addition, including the following embodiment, the same step number is attached | subjected to the same part as the process demonstrated in 1st Embodiment according to the flowchart of FIG. 4, the description is abbreviate | omitted suitably, and it demonstrates centering on a different part.
As in the first embodiment, the main control ECU 21 acquires the state quantities θ _W , θ ₁ , λ _F , and λ _R from the sensor (step 1), and acquires the steering operation amount of the passenger (step 2). Then, the deceleration target value α ^* is determined (step 3), and the driving wheel angular speed target value {θ _W ^* } is determined (step 4).
The main control ECU 21 determines whether or not the inclination command value input from the vehicle body inclination command device 32 exists in the input device storage unit (step 41).

When the vehicle body inclination command value is stored (step 41; Y), the main control ECU 21 determines the maximum vehicle body inclination angle θ1 _{, Max} corresponding to the vehicle body inclination command value from the relationship shown in FIG. The value of the maximum vehicle body inclination angle used in Equations 1 and 2 is updated (Step 42).
On the other hand, when the vehicle body inclination command value is not stored (step 41; N), that is, when the passenger does not set the vehicle body inclination by operating the vehicle body inclination command device 32, the main control ECU 21 Step 42 is skipped and the process proceeds to Step 5. In this case, the maximum vehicle body inclination angle θ _{1, Max} is used as a default value determined in the same manner as in the first embodiment.

Thereafter, as in the first embodiment, the main control ECU 21 determines both target values θ ₁ ^* and b ^* of the vehicle body inclination angle and auxiliary wheel position (step 5), and the target value λ _F ^* of the rod expansion / contraction amount ^. , Λ _R ^* (step 6), output command values τ _W , T _F , T _R of each actuator are determined (step 7), and output command values τ _W , T _F , T _R are assigned to each control system. Supply (step 8) and return to the main routine.

Next, a third embodiment will be described.
As described in the first embodiment, the auxiliary wheel 15 moves to the target position b ^* by feedback control. For this reason, when a movement delay occurs, braking (braking) is applied before the auxiliary wheel 15 reaches the target position b ^* of the auxiliary wheel, so that the vehicle body is temporarily inclined forward or the driving wheel slips. there's a possibility that.
Therefore, in the third embodiment, the target deceleration rate α ^* is limited until the auxiliary wheel 15 reaches the target position b ^* with respect to the “delay” of the movement of the auxiliary wheel 15. Specifically, the target deceleration rate α ^* is limited by the actual auxiliary wheel position b.
Thereby, it is possible to prevent the balance during deceleration due to the vehicle body inclination and the auxiliary wheel grounding from being lost, and to prevent the vehicle from leaning forward or slipping. Moreover, it can function also as a fail safe when the movement system of the auxiliary wheel 15 breaks down.

The configuration of the control unit in the third embodiment is the same as that of the first embodiment described in FIG.
FIG. 9 is a flowchart showing the contents of the deceleration traveling control process in the third embodiment.
As in the first embodiment, the main control ECU 21 acquires the state quantities θ _W , θ ₁ , λ _F , and λ _R from the sensor (step 1), and acquires the steering operation amount of the passenger (step 2). Then, the deceleration target value α ^* is determined (step 3).

Then, the main control ECU 21 determines the current auxiliary wheel position b from the following equation 6 (step 31).
Formula 6 corresponds to the auxiliary wheel position control mechanism (rod actuators F62 and R63) shown in FIG. 1. As described in the first embodiment, when another mechanism is employed, The auxiliary wheel position b is determined by a mathematical formula corresponding to the structure adopted instead of 6.

(Formula 6)
b = ((λ _R + l ₀ ) ² − (λ _F + l ₀ ) ² ) / (4 dcos θ ₁ ) + (R _W −r _W ) tan θ ₁

Next, the main control ECU 21 determines a deceleration limit value α _lim corresponding to the current auxiliary wheel position b (step 32).
Tan η in Expression 7 is determined from Expression 7-2 using the current auxiliary wheel position b, and M _b is determined from Expression 7-3.

(Formula 7)
α _lim = (sin θ ₁ + tan η) / (cos θ ₁ + tan γ)

(Formula 7-2)
tan η = (M _b b) / (m ₁ l ₁ )
(Formula 7-3)
M _b = (1− (α ^* / μ)) M

In the third embodiment, the deceleration limit α _lim is defined by the slip limit, but the deceleration limit may be defined by the fall limit. In this case, M _b = M in Expression 7-3.
Further, the safety of control may be enhanced by dividing the deceleration limit obtained by the above equation 7 by the safety factor.

When the deceleration limit value α _lim determined corresponding to the current auxiliary wheel position b is smaller than the deceleration target value α ^* determined in step 3, the main control ECU 21 uses the deceleration used in step 4 decreasing up to the limit value alpha _lim determining the target value alpha ^* (step 33).
For example, when the deceleration determined in step 3 is 0.4 G and the deceleration limit value α _lim corresponding to the current auxiliary wheel position b is 0.3 G, the deceleration target value α used in step 4 is set. Reduce ^* to 0.3G.

The main control ECU 21 determines the target value {θ _W ^* } of the driving wheel angular velocity from the target value α ^{* of} deceleration corrected in step 33 (step 4).
Thereafter, the main control ECU 21 determines both target values θ ₁ ^* and b ^* of the vehicle body inclination angle and the auxiliary wheel position as in the first embodiment (however, the value of α ^* in this case is determined in step 3). (Use the deceleration target value before the limit) (step 5), determine the target values λ _F ^* and λ _R ^* of the rod expansion / contraction amount (step 6), output command values τ _W , T _F , T _R is determined (step 7), output command values τ _W , T _F and T _R are supplied to each control system (step 8), and the process returns to the main routine.

Next, a fourth embodiment will be described.
In the fourth embodiment, when slip of the drive wheel 11 is detected by the slip detection means, the ground contact position of the auxiliary wheel 15 is moved further forward while maintaining the vehicle body inclination angle. As a result, the center of gravity of the vehicle body relatively moves from the auxiliary wheel 15 side to the driving wheel 11 side, and the ground load on the driving wheel 11 increases, so that the vehicle can escape from the slip state.
The configuration of the control unit in the fourth embodiment is the same as that of the first embodiment described in FIG.

FIG. 10 is a flowchart showing the contents of the deceleration traveling control process in the fourth embodiment.
As in the first embodiment, the main control ECU 21 acquires the state quantities θ _W , θ ₁ , λ _F , and λ _R from the sensor (step 1), and acquires the steering operation amount of the passenger (step 2). Then, the deceleration target value α ^* is determined (step 3), and the driving wheel angular speed target value {θ _W ^* } is determined (step 4).

Then, the main control ECU 21 determines whether or not the drive wheel 11 is in a slip state (step 43).
As a method for determining whether or not the drive wheel 11 is in a slip state, for example, a method using an observer based on a dynamic model for the rotational motion of the drive wheel 11, a value of an acceleration sensor mounted on the vehicle, and the drive wheel 11 are used. Judging by the method of comparing the rotation speed of

Next, the main control ECU 21 determines the current auxiliary wheel position b (step 44).
This process is the same as step 31 of the third embodiment, and the main control ECU 21 determines the current auxiliary wheel position b from the above-described equation 6.
Then, the main control ECU 21 corrects the value of the static friction coefficient μ used in Expressions 2 and 3 to a value obtained from Expression 8 (Step 45).

(Formula 8)
μ = α / (1- (m ₁ l ₁ / Mb) ((cos θ ₁ + tan γ) α-sin θ ₁ ))

The acceleration α in Expression 8 is obtained from the history of the rotational speed of the drive wheel immediately before the slip or the value of the acceleration sensor mounted on the vehicle.
In addition, the estimation method (estimated value) may be stabilized by applying the calculated value of Formula 8 to a low-pass filter.

Thereafter, as in the first embodiment, the main control ECU 21 determines both target values θ ₁ ^* and b ^* of the vehicle body inclination angle and auxiliary wheel position (step 5), and the target value λ _F ^* of the rod expansion / contraction amount ^. , Λ _R ^* (step 6), output command values τ _W , T _F , T _R of each actuator are determined (step 7), and output command values τ _W , T _F , T _R are assigned to each control system. Supply (step 8) and return to the main routine.

In the fourth embodiment, once the vehicle slips and the static friction coefficient estimated value decreases, the value is not recovered unless the control is once finished. However, the input device includes a reset signal transmission device, and the input signal You may initialize the value with.
Further, the value may be gradually recovered with time.

Next, a fifth embodiment will be described.
The fifth embodiment is processing corresponding to emergency braking. During emergency braking, a large braking force is required and it is necessary to decelerate as soon as possible.
When decelerating, the drive wheel 11 is tilted backward to maintain balance, but the vehicle temporarily accelerates due to the reaction of the drive wheel torque that tilts the vehicle back, and emergency braking starts when the vehicle tilts (Time loss).
Therefore, in the fifth embodiment, traveling control (deceleration control) is prioritized over vehicle body posture control during emergency braking. Specifically, when a request for emergency braking is detected, the vehicle is decelerated while maintaining the vehicle body posture by immediately contacting the auxiliary wheel 15 to the target position without tilting the vehicle body backward.

The configuration of the control unit in the fifth embodiment is the same as that of the first embodiment described in FIG.
FIG. 11 is a flowchart showing the contents of the deceleration traveling control process in the fifth embodiment.
As in the first embodiment, the main control ECU 21 acquires the state quantities θ _W , θ ₁ , λ _F , and λ _R from the sensor (step 1), and acquires the steering operation amount of the passenger (step 2). Then, the deceleration target value α ^* is determined (step 3), and the driving wheel angular speed target value {θ _W ^* } is determined (step 4).

  The main control ECU 21 determines whether or not the occupant requests emergency braking (step 46). Whether or not emergency braking is requested in this embodiment is determined from the acceleration / deceleration command value supplied from the input device 30 and the rate of change thereof, but is determined from the signal from the emergency braking command input device to the input device 30. You may do it.

If emergency braking is not requested (step 46; N), the main control ECU 21 moves the process to step 5, and in this case, the same process as in the first embodiment is performed.
On the other hand, when emergency braking is requested (step 46; Y), the main control ECU 21 corrects the value of the maximum vehicle body inclination angle θ _{1, Max} used in Equations 1 and 2 to θ _{1, Max} = 0. .
As a result, the target value θ ₁ ^* = 0 of the vehicle body tilt angle is eliminated, and temporary acceleration and time loss due to the vehicle body tilt are eliminated.

Thereafter, as in the first embodiment, the main control ECU 21 sets both the target values θ ₁ ^* and b ^* of the vehicle body inclination angle and the auxiliary wheel position to Equations 1 and 2 (the values of θ _{1 and Max depending on} whether correction is made). was determined from the change) (step 5), the target value lambda _F ^* of rod deformation amount, lambda _R ^* was determined (step 6), the output command value tau _W, T _F of each actuator, to determine the T _R ( Step 7), supply the output command values τ _W , T _F , T _R to each control system, and return to the main routine.

In the fifth embodiment described, during emergency braking, the target value θ ₁ of the vehicle body tilt angle is set to zero and the auxiliary wheel 15 is decelerated while maintaining the upright posture, but the target value θ ₁ of the vehicle body tilt angle is set to be negative. Alternatively, the vehicle may be decelerated while being tilted forward. Thereby, the reaction force of the vehicle body forward tilt torque can be compensated as the deceleration torque.
Further, the attitude control may not be performed (abandoned) by setting the feedback gains K _W3 and K _W4 in Expression 4 to zero.

In each of the described embodiments, as shown in FIG. 5 and Formula 2, when the deceleration target value α ^* is equal to or greater than the threshold value α _Max , the auxiliary wheel position target value b ^* is set to the deceleration target value α. ^Although it is increased with ^* , the target value b ^* may be a constant value.
That is, in the formula 2, when α ^* ≧ α _Max , b ^* = b ₀ , so that when the deceleration target value α ^* is equal to or greater than the threshold value α _Max , in the case of deceleration, the front side In the case of acceleration, the auxiliary wheel 15 is grounded at a position b ₀ at a predetermined distance from each of the rear driving wheels 11.
As the predetermined value b ₀ , for example, a position value corresponding to the assumed maximum acceleration / deceleration value is given in advance.
In this case, it is not necessary to move the auxiliary wheel 15 back and forth by an arbitrary amount in accordance with acceleration / deceleration. Therefore, for example, auxiliary wheels 15F and 15R that can appear and disappear may be arranged at front and rear positions corresponding to the assumed maximum acceleration / deceleration.

Further, in each of the embodiments described above, the target position of the auxiliary wheel 15 when not in contact with the ground is b ^* = 0 (Formula 2), and the vehicle body inclination angle θ ₁ with the deceleration target value α ^* <threshold α _Max is satisfied. On the other hand, the auxiliary wheel 15 is always kept waiting at δ immediately above the ground contact position closest to the drive wheel 11 (Equation 3). Therefore, when necessary, it can be quickly grounded to an appropriate position, and the effect of grounding the auxiliary wheel 15 can be obtained early.
In this regard, the standby position of the auxiliary wheel may be changed according to the vehicle traveling speed in order to be able to respond quickly to changes in acceleration / deceleration. For example, the auxiliary wheels may be moved backward in advance to prepare for sudden acceleration when stopped, and the auxiliary wheels may be moved forward to prepare for sudden braking when traveling near the maximum speed.
In order to save energy, the auxiliary wheel standby position may not be controlled at all when not in use.

It is an appearance lineblock diagram of the state where the crew member got about the vehicle in this embodiment. It is a block diagram of a control unit. It is a figure showing the dynamic model of the vehicle attitude control system in this embodiment. It is a flowchart showing the deceleration traveling control process in 1st Embodiment. Deceleration with respect to the target value alpha ^*, the target value theta ₁ ^* of the vehicle body tilt angle, a relationship diagram of a target value b ^* of the auxiliary wheel position. It is a block diagram of the control unit in 2nd Embodiment. FIG. 6 is a relationship diagram between _an inclination command and a maximum vehicle body inclination angle θ _{1, Max} . It is a flowchart showing the deceleration traveling control process in 2nd Embodiment. It is a flowchart showing the deceleration traveling control process in 3rd Embodiment. It is a flowchart showing the deceleration traveling control process in 4th Embodiment. It is a flowchart showing the deceleration traveling control process in 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Drive wheel 12 Drive motor 13 Riding part 14 Support member 15 Auxiliary wheel 131 Seat surface part 132 Backrest part 133 Headrest 16 Control unit 20 Control ECU
21 Main control ECU
22 Drive wheel control ECU
23 Rod control ECU
30 Input device 31 Steering device 40 Car body control system 41 Angle meter 50 Drive wheel control system 51 Drive wheel rotation angle meter 52 Drive wheel actuator 60 Rod control system 61 Rod drive motor rotation angle meter 62 Rod actuator F
63 Rod actuator R

Claims (5)

A drive wheel arranged on one axis;
A vehicle body including the riding section;
Requested acceleration obtaining means for obtaining the requested acceleration of the vehicle;
Travel control means for maintaining the vehicle body including the riding section in an inverted state by controlling the torque of the drive wheel, and traveling according to the acquired requested acceleration;
A grounding member disposed such that a grounding state and a non-grounding state can be selected in front of or behind the driving wheel;
A grounding member control means for grounding the grounding member in a direction opposite to the direction of acceleration with respect to the drive wheel when the acquired absolute value of the requested acceleration is equal to or greater than a predetermined threshold;
Position acquisition means for acquiring the position of the grounded ground member;
When the absolute value of the limit acceleration corresponding to the acquired position of the grounding member is smaller than the absolute value of the acquired required acceleration, the required acceleration used by the travel control means is corrected to a value equal to or less than the limit acceleration. Correction means;
A vehicle characterized by comprising:
2. The vehicle according to claim 1, wherein the grounding member control unit grounds the grounding member at a position further away from the driving wheel as the absolute value of the acquired acceleration increases.
The grounding member control means is configured such that, when the grounding member is not grounded, the grounding member is located at a position on a vertical line passing through the rotation axis of the drive wheel, or at a grounding position when the absolute value of the required acceleration is a predetermined threshold value. The vehicle according to claim 1, wherein the vehicle is placed on standby with a predetermined distance.
Selecting means for selecting the maximum value of the vehicle body inclination angle of the vehicle body;
4. The vehicle according to claim 1, wherein the grounding member control means sets an acceleration corresponding to the selected maximum value of the vehicle body inclination angle as the predetermined threshold value. 5.
In the grounding state of the grounding member, comprising slip detecting means for detecting slip of the driving wheel
The ground contact member control means moves the ground contact member in a direction away from the drive wheel when slippage of the drive wheel is detected. The vehicle according to claim 1.

Images