JP2011178328A - Vehicle and vehicle control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure proper responsiveness in inclination control of a wheel when traveling at a low speed. <P>SOLUTION: This vehicle is stabilized by inclining the vehicle to the turning inside in turning, and controls an inclination of the vehicle at a balancing angle between centrifugal force and gravity to the turning outside. At that time, for restraining excessive responsiveness of the inclination control, though a synthetic value of acceleration sensors 2 and 3 is used for control after filtering by a low pass filter, a cutoff frequency is reduced at a very low speed, for example, 2(km/h) or less. However, when the cutoff frequency in a low speed area is reduced, since there is a case of being unable to smartly cope with sudden input, when large input is observed in lateral acceleration in a low speed area, the cutoff frequency is temporarily enhanced, to cope with it. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle and a vehicle control program, and relates to, for example, a vehicle body tilting device.

In recent years, the number of vehicles owned has increased, and one person tends to own one vehicle.
However, for example, when one person rides a vehicle made for a large number of people, such as a five-seater vehicle, there is a problem that fuel is consumed wastefully and is uneconomical.
Therefore, recently, there is a demand for the development of a small vehicle that can be ridden by a small number of people, such as “Motorcycle and Tricycle” of Patent Document 1.
This technology improves the weight balance of a vehicle in a tandem ride two or three-wheeled vehicle by disposing the engine between the driver's footrests.

JP 2008-155671 A

By the way, in order to improve the weight balance of the vehicle, it is desirable to balance the centrifugal force and gravity by tilting the vehicle body when turning.
For this purpose, it is conceivable to detect the lateral acceleration acting on the vehicle body at the time of turning and feedback control the inclination angle of the vehicle body to an appropriate inclination angle (an angle at which a lateral force does not act on the passenger).
By this control, the left and right wheels are equally weighted, so that the vehicle is stabilized and the ride comfort of the passenger is improved.

Further, when such tilt angle control is performed, in order to suppress an excessive response of the tilt angle, it is desirable to perform feedback control after removing the high frequency component of the detected value of the lateral acceleration with a low-pass filter.
In addition, when driving at extremely low speeds, it reacts excessively if it has the same responsiveness as at high speeds, so the time constant of the low-pass filter is increased to lower the cut-off frequency and to remove components on the lower frequency side. desirable.

  However, by reducing the cut-off frequency, excessive response during low-speed driving is suppressed.For example, when one side of the rear wheel falls on a step or rides on a protrusion, When the response is required, the response is slow. However, if control is performed in pursuit of high responsiveness in preparation for a step drop or the like, there is a problem that the device moves too quickly during normal use.

  An object of the present invention is to ensure appropriate responsiveness in controlling the tilt angle of a vehicle body during low-speed traveling.

In order to achieve the above object, according to the present invention, in the first aspect of the present invention, a pair of wheels, a vehicle body capable of adjusting an angle with respect to a line segment connecting the centers of the pair of wheels, and a lateral surface generated in the vehicle body. Lateral acceleration acquisition means for acquiring acceleration, angle control means for controlling the angle of the vehicle body so that the acquired lateral acceleration becomes a predetermined target value, and when the acquired lateral acceleration is a predetermined threshold value or more, There is provided a vehicle characterized by comprising responsiveness adjusting means for improving the responsiveness of the angle control means.
The invention according to claim 2 provides the vehicle according to claim 1, wherein the angle control means adjusts the angle of the vehicle body by inclining the pair of wheels.
The invention according to claim 3 provides the vehicle according to claim 1, wherein the angle control means adjusts the angle of the vehicle body by tilting the vehicle body with respect to the pair of wheels. .
According to a fourth aspect of the present invention, vehicle speed acquisition means for acquiring a vehicle speed is provided, and the responsiveness adjusting means reduces the responsiveness of the angle control means when the acquired vehicle speed is less than a predetermined threshold. 3. The responsiveness of the angle control means is enhanced when the acquired lateral acceleration becomes a predetermined threshold value or more during the adjustment and the low adjustment. A vehicle according to item 3 is provided.
According to a fifth aspect of the present invention, the lateral acceleration acquisition unit acquires a lateral acceleration and a combined lateral acceleration output from a plurality of lateral acceleration sensors, and the angle control unit receives the combined lateral acceleration from the lateral acceleration acquisition unit. The responsiveness adjusting means acquires the value of one of the plurality of lateral acceleration sensors from the lateral acceleration acquiring means. A vehicle according to one claim is provided.
In a sixth aspect of the present invention, the plurality of lateral acceleration sensors are provided on one side of a rotation center when the vehicle body is rotated to control the angle of the vehicle body, and the responsiveness adjusting means The vehicle according to claim 5, wherein a value of a lateral acceleration sensor installed on a side far from the center of rotation is acquired.
According to a seventh aspect of the present invention, the angle control unit acquires a lateral acceleration filtered by a low-pass filter included in the lateral acceleration acquisition unit, and the responsiveness adjusting unit increases a cutoff frequency of the low-pass filter. The vehicle according to any one of claims 1 to 6, wherein the responsiveness of the angle control means is enhanced by the above.
According to an eighth aspect of the present invention, in a vehicle computer comprising a pair of wheels and a vehicle body capable of adjusting an angle with respect to a line segment connecting the centers of the pair of wheels, a lateral acceleration generated in the vehicle body is acquired. A lateral acceleration acquisition function, an angle control function for controlling the angle of the vehicle body so that the acquired lateral acceleration becomes a predetermined target value, and the angle control function when the acquired lateral acceleration is equal to or greater than a predetermined threshold. The vehicle control program which implement | achieves the responsiveness adjustment function which improves the responsiveness of this is provided.

  According to the present invention, when the input amount of the lateral acceleration is monitored and a magnitude greater than a certain level is detected, responsiveness is ensured by temporarily reducing the time constant of the low-pass filter.

It is a figure showing the vehicle of this Embodiment. It is a functional block diagram of inclination control ECU which concerns on this Embodiment. It is a figure for demonstrating a cut-off frequency. It is a flowchart for demonstrating the control process of a link mechanism. It is a flowchart for demonstrating an acceleration calculation process. It is a flowchart for demonstrating an acceleration filter process. It is a figure showing the numerical formula which calculates the acceleration for control. It is a flowchart for demonstrating inclination control processing. FIG. 10 is a functional block diagram of an inclination control ECU according to Modification 1. It is a flowchart for demonstrating the control process of a link mechanism. It is a flowchart for demonstrating a calculation inclination control process. It is a figure for demonstrating the modification 2. FIG.

(1) Outline of Embodiment In a vehicle in which the vehicle is tilted inward while being turned and stabilized, the inclination of the vehicle is controlled to an angle at which the centrifugal force to the outside of the turn and gravity are balanced (that is, an angle at which the lateral acceleration becomes zero). Then, the force acting on the passenger and the vehicle body is downward in the direction perpendicular to the seat surface of the seat (when the vehicle is inclined by tilting the wheel, the direction parallel to the plane including the wheel), and the passenger's uncomfortable feeling is reduced. And the stability of the vehicle is improved.
Further, when this control method is used, even if the road surface is inclined in a direction perpendicular to the traveling direction, the force acting on the vehicle body can be made vertical.

In order to perform such control, the vehicle 1 (FIG. 1) of the present embodiment is provided with an acceleration sensor so as to detect lateral acceleration in the vehicle body 10 that is a tilt control target, and the output thereof is a target value. The inclination angle of the vehicle body 10 is feedback-controlled so as to be (here, 0).
In the present embodiment, in order to perform more appropriate control, the acceleration sensors 2 and 3 are installed in the vehicle body unit 10 and the resultant lateral acceleration is controlled to be zero.

  By the way, in order to suppress an excessive response of the tilt control, the vehicle 1 uses the combined value of the acceleration sensors 2 and 3 after filtering with a low-pass filter, but for example, 2 (km / h) or less. When the front wheel 15 turns at a large steering angle, the output of the drive motor fluctuates and the lateral acceleration changes, which causes the vehicle body 10 to shake to the left and right. Since it is easy to feel pleasure, the time constant of the low-pass filter is increased in the low speed region (the reciprocal of the time constant is the cut-off frequency), and the cut-off frequency is lowered.

  However, if the cut-off frequency in the low speed region is lowered, the vehicle 1 may not be able to respond quickly to an unexpected input such as the vehicle 1 falling on a step, so the vehicle 1 monitors the output of the acceleration sensor 2 and operates at a low speed. When a large input is observed in the lateral acceleration in the region, the time constant is temporarily reduced to increase the cut-off frequency, and agile control is performed to cope with this.

  More specifically, a low cut-off frequency (for example, 5 (Hz)) is used at low speeds to reduce agility, and when a large lateral acceleration is observed, the cut-off frequency is increased to a high value (for example, 15 ( Hz)) to temporarily achieve agile responsiveness.

(2) Details of Embodiment FIG. 1A is a side view of the vehicle 1 of the present embodiment.
The vehicle 1 has a single front wheel 15 and a pair of rear wheels 5R and 5L (5L not shown) provided on the left and right sides, and a vehicle body 10 on which a passenger's driver's seat is provided is provided therebetween. Is provided.
Further, the wheel base (distance from the center of the rear wheels 5R, 5L to the center of the front wheel 15) is LH.

The front wheel 15 can be directed in the steering direction by the steering operation of the passenger and functions as a steering wheel.
On the other hand, the rear wheel 5R incorporates a travel drive motor 6R (in-wheel), and generates a driving force corresponding to the passenger's throttle operation detected by the throttle opening sensor 12. The rear wheel 5L (not shown) similarly includes a travel drive motor 6L (not shown), and operates in the same manner as the travel drive motor 6R.

The steering angle sensor 13 is provided in the steering unit and detects the steering angle of the front wheels 15 by the steering operation of the passenger.
The vehicle speed sensor 14 is provided on the axle of the front wheel 15 and detects the vehicle speed of the vehicle 1.
The throttle opening sensor 12 is provided in the steering section and detects the throttle opening adjusted by the passenger by hand.

The acceleration sensor 2 is provided on the back side of the backrest portion of the driver's seat, and the lateral acceleration of the vehicle body portion 10, that is, the acceleration acting in the left-right direction of the vehicle body portion 10 (left-right direction in the coordinate system fixed to the vehicle body portion 10). Is detected.
The acceleration sensor 3 is provided at the back of the seat of the driver's seat and detects the lateral acceleration of the vehicle body portion 10, that is, the acceleration acting in the left-right direction (the left-right direction in the coordinate system fixed to the vehicle body portion 10). As described above, two lateral acceleration sensors are provided because of the acceleration detected by the lateral acceleration sensor, the vehicle body 10 is shaken by the lateral acceleration due to the operation of the link motor 7 and the unevenness of the road surface, or the mechanism This is because it is desired to obtain only the lateral acceleration which is the sum of the centrifugal force acting on the vehicle body portion 10 and the gravitational component force, excluding the lateral acceleration due to backlash. Details will be described later.

A storage 11 is provided under the driver's seat of the vehicle body 10 and stores a battery that supplies power to the travel drive motors 6R and 6L, an ECU (Electronic Control Unit) that electronically controls the operation of the vehicle 1, and the like. Yes.
The ECU includes a travel control ECU that controls the driving force of the rear wheels 5R and 5L, and a tilt control ECU that controls the tilt of the vehicle body 10.

  These ECUs include a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage medium such as a semiconductor or a hard disk, and the CPU is in accordance with programs stored in the storage medium. The control process is performed.

FIG. 1B is a rear view of the vehicle body 10 as viewed from the rear.
The rear wheels 5R and 5L are connected by a link mechanism 20.
The link mechanism 20 includes the vertical link units 9R and 9L provided vertically inside the rear wheels 5R and 5L, and the horizontal link unit 8U that connects the upper and lower portions of the vertical link units 9R and 9L. , 8D.

The connecting portions of the vertical link units 9R and 9L and the horizontal link units 8U and 8D are joined by a shaft provided in the front-rear direction of the vehicle body 10 so as to be rotatable.
Further, a central vertical member 18 coupled with the same shaft is provided at the center of the horizontal link units 8U and 8D, and the central vertical member 18 holds the vehicle body portion 10.

A link motor 7 is provided at the joint between the horizontal link unit 8U and the central vertical member 18, and the stator side of the link motor 7 is fixed to the central vertical member 18, and the rotor side is fixed to the horizontal link unit 8U. Has been.
Alternatively, the stator side may be fixed to the horizontal link unit 8U, and the rotor side may be fixed to the central vertical member 18.

The link motor 7 is a drive motor that drives the link mechanism 20, and since the stator side is fixed to the central vertical member 18 and the rotor side is fixed to the horizontal link unit 8U, the link mechanism 20 is parallel when the link motor 7 rotates. Transform into a quadrilateral.
When the link mechanism 20 is a parallelogram, the vertical link units 9L and 9R and the central vertical member 18 are kept parallel, so that the vehicle body is parallel to the rear wheels 5R and 5L as shown in FIG. The part 10 is also inclined with respect to the road surface. Note that the inclination angle of the link mechanism 20 is equal to the inclination angle of the vehicle body 10.

The acceleration sensors 2 and 3 are installed at positions of heights L1 and L2 from the road surface on the side of the vehicle body portion 10 inclined by the link mechanism 20, respectively. Further, when the vehicle body 10 is supported by a spring such as a suspension, it is installed on a so-called “spring top”.
The acceleration sensors 2 and 3 are preferably attached to sufficiently rigid members so as not to detect the lateral acceleration due to the deflection of the vehicle body portion 10.

Since the acceleration sensors 2 and 3 are fixed to the vehicle body portion 10, the coordinate axes of the acceleration sensors 2 and 3 are fixed to the vehicle body portion 10.
Therefore, the acceleration sensors 2 and 3 detect lateral acceleration (a lateral acceleration due to turning, a lateral component of the gravitational acceleration caused by the inclination of the vehicle body 10) in a coordinate system fixed to the vehicle body 10.

Further, the acceleration sensors 2 and 3 synthesize the outputs so that the centrifugal force and the gravity force acting on the vehicle body 10 except for the component that the link mechanism 20 tilts out of the lateral acceleration generated in the vehicle body 10. It is provided to calculate the sum acceleration component.
In order to remove the component that the link mechanism 20 inclines by synthesis, it is necessary to install both on the upper side or the lower side of the link rotation center (the rotation axis of the link motor 7) (that is, one of the rotation centers). In order to improve accuracy, one (acceleration sensor 3 in this example) is as close to the rotation center of the link (rotation center of the vehicle body 10) as possible (FIG. 12 (a)). And in the case of the swing type vehicle described in (b)).

The acceleration sensors 2 and 3 are installed between the front wheel 15 and the rear wheels 5R and 5L, and are preferably installed as close to the passenger as possible in order to detect the lateral acceleration felt by the passenger.
Furthermore, it is preferable that the acceleration sensors 2 and 3 are provided on the same vertical axis and are not installed offset in the traveling direction.
In addition, it is desirable that the height difference ΔL = L1−L2 between the acceleration sensors 2 and 3 is set to be 0.3 meters or more.
Furthermore, it is desirable that the acceleration sensors 2 and 3 be installed so that a direction perpendicular to the radial direction of rotation of the vehicle body 10 can be detected.

FIG. 1C shows a state in which the vehicle body 10 is tilted by operating the link mechanism 20 so that the lateral acceleration acting on the vehicle body 10 becomes zero when the vehicle 1 turns to the right. .
As shown in the drawing, the rear wheels 5R and 5L have a round bottom tire surface like a two-wheeled vehicle, and can be satisfactorily grounded even if they are inclined. Further, since the weight is applied equally to the rear wheels 5R and 5L, the traveling is also stable.

  The lateral acceleration detected by the acceleration sensor 2 is a1, and the lateral acceleration detected by the acceleration sensor 3 is a2. In this case, the composite value as of acceleration is expressed by the following formula (1) or formula (2) as Δa = a1−a2.

  as = a2- (L2 / ΔL) · Δa (1)

  as = a1- (L1 / ΔL) · Δa (2)

  The calculations of Equation (1) and Equation (2) are both the same in calculation, but in actual use, the calculation is based on the output of the sensor closer to the road surface, that is, the acceleration sensor 3. It turned out to be better. Therefore, in this embodiment, a composite value of lateral acceleration is calculated using equation (1).

FIG.1 (d) is a figure for demonstrating in detail the lateral acceleration a1 of FIG.1 (c).
The acceleration sensor 2 is subjected to lateral acceleration (acceleration that causes centrifugal force) and gravity acceleration that occur in the direction of turning outward, and in this example, the acceleration sensor 2 is a component of a horizontal component that is fixed to the vehicle body 10. The difference is detected as a1.

FIG. 1E shows a state where the link mechanism 20 is tilted so that the vehicle body 10 is vertical on a road surface with a level difference.
When there is a step 100 on the road surface when the vehicle 1 is traveling straight, the vehicle 1 tilts the rear wheels 5R and 5L using the link mechanism 20 so that the vehicle body 10 is vertical.
A normal vehicle tilts according to the road surface, but the vehicle 1 tilts the vehicle body portion 10 so that the lateral acceleration becomes 0. Therefore, when the vehicle 1 runs along a contoured road surface or slope, the vehicle body portion 10 is vertical. It can control to become.

FIG. 2 is a functional block diagram of the inclination control ECU 30 that controls the inclination angle of the link mechanism 20.
These configurations are configured by the CPU of the inclination control ECU 30 executing a predetermined program.
The tilt control ECU 30 includes an acceleration calculation unit 31, an acceleration filter unit 32, and a tilt control unit 33.
The acceleration calculation unit 31 acquires the detected value of the lateral acceleration from the acceleration sensors 2 and 3, calculates the combined lateral acceleration as using Equation (1), and outputs the resultant to the acceleration filter unit 32.

The acceleration filter unit 32 filters as with a low-pass filter and cuts high frequency components.
The acceleration filter unit 32 monitors the output of the acceleration sensor 2 and switches the cutoff frequency of the low-pass filter according to the detection value.

  More specifically, the acceleration filter unit 32 sets the cut-off frequency low during low-speed traveling (for example, 2 (km / h) or less) and suppresses an excessive response of the inclination control ECU 30. When the lateral acceleration suddenly occurs as in the case where the rear wheel 5R falls on a step, this is detected by the acceleration sensor 2, and the cut-off frequency is increased so that the link mechanism 20 reacts quickly. .

In this way, in order to immediately switch the cutoff frequency when lateral acceleration suddenly occurs, the acceleration filter unit 32 uses the raw value of the acceleration sensor 2 rather than the combined value of the acceleration calculation unit 31 that requires time for calculation. Switches the cutoff frequency.
Although the raw value of the acceleration sensor 3 can be used, since the acceleration sensor 2 at a higher position has a greater change in lateral acceleration than the acceleration sensor 3 at a lower position, the acceleration sensor 2 is used. did.

The inclination control unit 33 outputs a torque command value to the link motor 7 so that the control acceleration aT output from the acceleration filter unit 32 becomes a target value (here, 0) by feedback control.
With this torque command value, the link motor 7 drives the link mechanism 20 to tilt the rear wheels 5R, 5L and the vehicle body 10 in the turning direction.

FIG. 3A is a diagram for explaining the cut-off frequency of the acceleration composite value.
This figure is a one-dimensional map when the magnitude | a1 | of the lateral acceleration a1 detected by the acceleration sensor 2 is less than the acceleration reference value aST (that is, when running normally), and the vertical axis is The cutoff frequency W (Hz) and the horizontal axis represent the vehicle speed ν (km / h).

W (ν) is a function in which the input is the vehicle speed and the output is the cutoff frequency, and can be expressed by an arbitrary function.
The threshold value a1 is a positive real number, and is experimentally obtained as a value that is not observed during normal traveling on a paved road and that a step fall can be observed in the initial stage.

  The acceleration filter unit 32 includes seven discrete points (−5, 15), (−3, 15), (−2, 5), (0, 5), (2, 5), ( 3, 15), (5, 15) (where (vehicle speed, cut-off frequency)) is set in advance, and the map of W (ν) is defined by complementing these with straight lines. W (ν) may be configured using a lookup table or the like. Thus, the low-pass filter used in the vehicle 1 is a cutoff frequency variable low-pass filter.

  As shown in the figure, when the vehicle speed detected by the vehicle speed sensor 14 (FIG. 1) is 3 (km / h) or higher, the acceleration filter unit 32 sets the cutoff frequency to 15 (Hz) and 2 (km / h). ) Or more and less than 3 (km / h), it increases sequentially from 5 (Hz) to 15 (Hz), and 0 (km / h) or more and less than 2 (km / h), 5 (Hz) Yes. The same applies to the negative vehicle speed (that is, when traveling backward).

  Thus, when the vehicle 1 travels at a low speed, the acceleration filter unit 32 suppresses an excessive response of the link mechanism 20 by lowering the cutoff frequency and cutting the high-frequency component of the lateral acceleration.

FIG. 3B shows a cutoff frequency when the magnitude | a1 | of the lateral acceleration a1 detected by the acceleration sensor 2 is equal to or greater than the acceleration reference value aST, for example, when the vehicle 1 falls on a step. Yes.
As shown in the figure, the acceleration filter unit 32 switches the cut-off frequency in the case of −3 to 3 (km / h) to 15 (Hz) when the vehicle 1 falls on a step. Thereby, the link mechanism 20 can respond quickly.

FIG. 4 is a flowchart for explaining a control process of the link mechanism 20 performed by the inclination control ECU 30.
The following processing is performed by the CPU of the inclination control ECU 30 according to a predetermined program.
First, the combined value of lateral acceleration is calculated by the acceleration calculating unit 31 (step 100), and then the acceleration filter unit 32 filters the combined value of lateral acceleration (step 200).
Then, the tilt control unit 33 controls the tilt of the link mechanism 20 so that the filtered lateral acceleration becomes the target value (step 300).

FIG. 5 is a flowchart for explaining the acceleration calculation processing in step 100 (FIG. 4).
First, the CPU of the inclination control ECU 30 acquires the acceleration sensor value a1 from the acceleration sensor 2 and stores it in a storage device (such as a RAM) (step 105).
Next, the CPU acquires the acceleration sensor value a2 from the acceleration sensor 3 and stores it in the storage device (step 110).

Next, the CPU calculates a difference Δa = a1−a2 between the a1 and a2 stored in the storage device and stores the difference in the storage device (step 115).
Next, the CPU calls the distance ΔL (= L1−L2) between the acceleration sensor 2 and the acceleration sensor 3 stored in advance from the storage device (step 120), and further stores the acceleration sensor 3 stored in advance. The height L2 is also called from the storage device (step 125).
Next, the CPU substitutes Δa, ΔL, and L2 into equation (1) to calculate a combined lateral acceleration as (step 130), and sends the as to the acceleration filter unit 32 (step 135).

FIG. 6 is a flowchart for explaining the acceleration filter processing in step 200.
Steps 205 to 245 are processes for setting the cut-off frequency of the low-pass filter, and steps 250 to 275 are processes for filtering the combined lateral acceleration as of the acceleration calculation unit 31.

First, the CPU sets a parameter Wp for adjusting the cutoff frequency of the low-pass filter to an initial value Wp = 5.
Next, the CPU acquires a raw value a1 of the acceleration sensor 2 (step 205).
Next, the CPU obtains the vehicle speed ν from the vehicle speed sensor 14, and based on this, calculates the cutoff frequency W using the map of FIG. 3A (step 210).

  Next, the CPU acquires a control cycle (sampling frequency) Ts (step 215). Ts is used as a parameter for gradually returning the cut-off frequency to 5 (Hz) when | a1 | ≧ aST is obtained at low speed and the cut-off frequency is 15 (Hz).

Next, the CPU determines whether Wp is 5 or less (step 220).
When Wp is 5 or less (step 220; Y), the CPU sets Wp = 5 (step 225). This is because a calculation error may result in a fraction such as Wp = 4.99..., And in this case, Wp is reset to 5.
After resetting Wp to 5, the CPU acquires the acceleration reference value aST from the storage device (step 230).

On the other hand, when Wp is larger than 5 (step 220; N), the CPU sets the parameter Wp to Wp-10 · Ts (step 240) and the cut-off frequency W to Wp (step 243).
Thus, when step 220 is N, Wp decreases by 10 · Ts for each sampling frequency Ts.

After step 230 or step 243, the CPU determines whether or not the absolute value of the raw value a1 of the acceleration sensor 2 is less than the acceleration reference value aST (step 235).
When the absolute value of the raw value a1 of the acceleration sensor 2 is equal to or greater than the acceleration reference value aST (step 235; N), that is, when the vehicle 1 falls on a step, the CPU sets the parameter Wp to 15. Then, the cutoff frequency W is set to 15 (step 245).

  After setting the cut-off frequency of the low-pass filter in the above steps, the CPU performs a filtering process on the vehicle speed ν as follows. In the present embodiment, as an example, IIR (Infinite Duration Impulse Response) is used.

When the absolute value of the raw value a1 of the acceleration sensor 2 is less than the acceleration reference value aST (step 235; Y) or after setting Wp and W to 15 in step 245, the CPU determines the vehicle speed ν from the vehicle speed sensor 14. Obtain (step 250).
Next, the CPU acquires the previous control acceleration aold stored in the storage device (step 255).

Next, the CPU acquires a sensor value as (step 260). The sensor value as is the combined lateral acceleration calculated by the acceleration calculation unit 31 according to the equation (1).
Next, the CPU calculates a control acceleration (acceleration filter value) aT obtained by filtering the sensor value as (step 265).
Here, the CPU adds the control cycle Ts, the cut-off frequency W (ν) acquired by mapping, the previous control acceleration aold (aold = a (t−1)), to the equation (3) shown in FIG. Then, the control acceleration aT is calculated by substituting the sensor value as (step 265).

Returning to FIG. 6, when the CPU calculates the control acceleration aT (step 265), it sends it to the tilt control unit 33 (step 270).
Next, the CPU stores the control acceleration aT in the storage device as the previous control acceleration aold (step 275).

FIG. 8 is a flowchart for explaining the tilt control process in step 300.
In the present embodiment, for example, the tilt angle of the link mechanism 20 is PI-controlled.
The CPU receives the control acceleration aT from the acceleration filter unit 32 (step 305).
Next, the CPU calls the previous control acceleration aold from the storage device (step 310).
Next, the CPU acquires a control cycle Ts (step 315).

Next, the CPU calculates a differential value ΔaT of the control acceleration aT by ΔaT = (aT−aold) / Ts (step 320).
Next, the CPU stores aT as aold in the storage device and updates the value of aold (step 325).

Next, the CPU calculates a control value Up (proportional term) by Up = Gp · aT (step 330). Here, Gp is a proportional gain. Next, the CPU calculates a control value Ud (differential term) by Ud = Gd · ΔaT (step 340). Here, Gd is a differential gain.

Next, the CPU calculates a control value U by U = Up + Ud (step 340), and outputs this to the link motor 7 as a torque command value (step 345).
The link motor 7 is driven according to the control value U, and the link mechanism 20 is tilted so that the control acceleration aT becomes a target value (here, 0).

Here, by using the acceleration sensors 2 and 3, the lateral acceleration caused by the operation of the link motor 7 and the vehicle body 10 is shaken due to the unevenness of the road surface, or the lateral acceleration caused by the backlash of the mechanism is detected by the acceleration sensor. Explain that it can be separated from
The accelerations output by the acceleration sensors 2 and 3 are the following four.
That is, (1) centrifugal force component ac during turning, (2) gravity force aG due to inclination, (3) lateral acceleration (backlash, deflection, etc.) due to movement of acceleration sensors 2 and 3 Things) aX1, aX2, (4) Lateral acceleration due to movement of the acceleration sensors 2, 3 (by the operation of the link motor 7) aM1, aM2.

  Here, aX1 = L1ωR ′, aX2 = L2ωR ′, aM1 = L1ωM ′, and aM2 = L2ωM ′. However, ωR is the acceleration of the vehicle body portion 10 due to the unevenness of the road surface or the backlash of the mechanism, ωM is the acceleration of the motor, and 'represents the differentiation with respect to time.

Then, the combined acceleration to be measured is a1 = ac + aG + L1ωR ′ + L1ωM ′ and a2 = ac + aG + L2ωR ′ + L2ωM ′. ωM ′.
Here, since a1-a2, L1-L2, and ωM ′ are known, an unknown value ωR ′ is determined.
That is, if there are two acceleration sensors, it is possible to calculate only the acceleration of the sum of the centrifugal force acting on the vehicle body 10 and the gravitational component force.

According to the embodiment described above, the following effects can be obtained.
(1) At extremely low speeds, by reducing the cut-off frequency of the low-pass filter, the excessive response at extremely low speeds can be suppressed to reduce discomfort caused by shaking, and the agility such as dropping the step to extremely low speeds. When a long response is required, the time constant can be temporarily increased to increase the cut-off frequency to ensure the required response, and control delay can be suppressed to prevent falls and the like.
(2) The control of the link mechanism 20 uses the combined value of the acceleration sensors 2 and 3 to perform more appropriate tilt control, and the cut-off frequency is switched by the acceleration sensor 2 installed on the upper side. By using the raw value, the cut-off frequency can be switched at high speed.

The vehicle 1 described above is a three-wheeled vehicle with two rear wheels and one front wheel. However, this is an example, and a two-wheeled vehicle that travels with two left and right wheels while balancing the front-rear direction. It can also be applied to vehicles with two or more motorcycles such as four wheels.
In the present embodiment, the lateral acceleration is filtered with a low-pass filter, and the responsiveness is adjusted by adjusting the cutoff frequency. However, other methods may be used.

(Modification 1)
In the present embodiment described above, the acceleration sensors 2 and 3 are used. However, in the present modification, a case will be described in which a single acceleration sensor is used and the inclination of the link mechanism 20 is controlled by the acceleration sensor 2.
Here, the reason why the acceleration sensor 2 is employed is that the acceleration sensor 2 of the acceleration sensors 2 and 3 is farther from the link motor 7, so that the change in the lateral acceleration becomes larger.

FIG. 9 is a functional block diagram of the inclination control ECU 40 that controls the inclination angle of the link mechanism 20 in the present modification.
The tilt control ECU 40 includes an acceleration filter unit 41 and a calculation tilt control unit 42.
The acceleration filter unit 41 acquires the lateral acceleration from the acceleration sensor 2 and performs filtering according to the maps shown in FIGS.
The calculation inclination control part 42 acquires a lateral acceleration from the acceleration filter part 41, and outputs a torque command to the link motor 7 so that this may become a target value (here 0).

FIG. 10 is a flowchart for explaining a control process of the link mechanism 20 performed by the inclination control ECU 40.
The following processing is performed by the CPU of the inclination control ECU 40 according to a predetermined program.
First, the acceleration filter unit 41 filters the output of the acceleration sensor 2 (step 400).
Next, the calculation inclination control unit 42 controls the inclination of the link mechanism 20 so that the filtered lateral acceleration becomes a target value (step 500).

The filtering process performed by the acceleration filter unit 41 in step 400 is the same as the acceleration filter process of FIG.
However, the raw value a1 of the acceleration sensor 2 is used as the sensor value as of step 260.

FIG. 11 is a flowchart for explaining the calculation tilt control process in step 500.
The CPU acquires the control acceleration aT from the acceleration filter unit 41 (step 505).
Next, the CPU calls aold (step 510), and further acquires the control cycle Ts (step 515).

Next, the CPU calculates a differential value of aT by aT = (aT−aold) / Ts (step 520), updates aold with aT, and stores it (step 525).
Next, the CPU calculates a control value Up = Gp · aT (step 530), further calculates a control value Ud = Gd · ΔaT (step 535), and adds both to calculate a control value U = Up + Ud. (Step 540).

Then, the CPU outputs the control value U as a torque command value to the link motor 7 (step 545), and the link motor 7 tilts the link mechanism 20.
As described above, in this modification, the link mechanism 20 can be controlled by the single acceleration sensor 2.

(Modification 2)
FIG. 12A is a rear view of the vehicle 1a according to Modification 2 as viewed from the rear.
The side view of the vehicle 1a is the same as FIG.
The vehicle 1 according to the embodiment described above tilts the vehicle body 10 by tilting the rear wheel 5R and the rear wheel 5L. However, the vehicle 1a according to this modification has the vehicle body 10 with respect to the rear wheels 5R and 5L. Tilt.

The link mechanism 20a has a fixed structure, and holds the rear wheels 5R and 5L so that the center axes of the rear wheels 5R and 5L coincide.
For this reason, when the link motor 7 rotates, the vehicle body 10 rotates about the rotation axis of the link motor 7 with respect to the link mechanism 20 and the rear wheels 5R and 5L as shown in FIG. .
The acceleration sensors 2 and 3 are mounted on the link motor 7. In this example, L1 and L2 are distances from the rotation axis of the link motor 7, respectively.

The control of the inclination angle of the vehicle body unit 10 is the same as in the case of the vehicle 1, and the lateral acceleration acting on the vehicle body unit 10 is controlled to be zero.
When the vehicle 1a is traveling at a low speed, the cut-off frequency of the low-pass filter is set low. However, when the vehicle body part 10 is tilted sharply, such as falling to a step, the cut-off frequency is increased to increase the response. Increase.

The following configuration can be obtained by the present embodiment and the modification described above.
The rear wheels 5R and 5L function as a pair of wheels.
When the link motor 7 is driven, the vehicle body portion 10 is inclined with respect to the line segment connecting the centers of the rear wheels 5R and 5L, and the inclination of the vehicle body portion 10 can be adjusted by controlling the amount of rotation of the link motor 7. The part 10 functions as a vehicle body whose angle with respect to a line segment connecting the centers of the pair of wheels can be adjusted.
In addition, the acceleration sensors 2 and 3 (acceleration sensor 2 in the first modification) function as a lateral acceleration acquisition unit that acquires the lateral acceleration generated in the vehicle body in order to detect the lateral acceleration of the vehicle body portion 10.
Further, since the inclination control ECU 30 controls the angle of the vehicle body 10 so that the lateral acceleration becomes a target value (here, 0), the inclination of the vehicle body is adjusted so that the acquired lateral acceleration becomes a predetermined target value. It functions as an angle control means for controlling.
When the magnitude of the lateral acceleration is equal to or greater than the predetermined threshold value aST, the tilt control ECU 30 increases the cutoff frequency to increase the response of the tilt control. Therefore, when the acquired lateral acceleration is equal to or greater than the predetermined threshold value. , Functioning as a responsiveness adjusting means for improving the responsiveness of the angle control means.

  In the embodiment and the first modification, the angle control is performed in order to adjust the inclination angle of the vehicle body 10 by inclining the rear wheels 5R and 5L with respect to the line segment connecting the centers of the rear wheels 5R and 5L. The means adjusts the angle of the vehicle body by inclining the pair of wheels.

  Further, in the second modified example, the vehicle body 10 is tilted with respect to the center line while keeping the center lines of the rear wheels 5R and 5L coincident with each other. The angle of the vehicle body is adjusted by tilting the vehicle body.

The vehicle speed sensor 14 functions as vehicle speed acquisition means for acquiring the vehicle speed.
Then, according to the map, the inclination control ECU 30 (acceleration filter unit 32) sets the cutoff frequency to 15 (Hz) when it is 3 (km / h) or more, and 5 when it is less than 3 (km / h). Set to -15 (Hz) and adjust the responsiveness low, and when the low acceleration is adjusted, if the lateral acceleration is greater than or equal to aST, the cutoff frequency is set to 15 (Hz) to increase the responsiveness. Therefore, the responsiveness adjusting means adjusts the responsiveness of the angle control means to a low level when the acquired vehicle speed is equal to or lower than a predetermined threshold value, and the acquired lateral acceleration is set to a predetermined level during the low adjustment. When the threshold value is exceeded, the responsiveness of the angle control means is enhanced.

Further, since the inclination control ECU 30 acquires the raw value a1 of the acceleration sensor 2 and acquires the combined lateral acceleration as of the acceleration sensors 2 and 3 by the acceleration calculation unit 31, the lateral acceleration acquisition means includes a plurality of lateral acceleration sensors. Obtains the lateral acceleration and the combined lateral acceleration output by.
The tilt control ECU 30 (tilt control unit 33) acquires the combined lateral acceleration as for controlling the link mechanism 20, and the tilt control ECU 30 (acceleration filter unit 32) adjusts the responsiveness (cutoff frequency). Therefore, in order to obtain the raw value a1 of the acceleration sensor 2, the angle control means obtains the combined lateral acceleration from the lateral acceleration obtaining means, and the responsiveness adjusting means comprises the plurality of lateral acceleration obtaining means from the plurality of lateral acceleration obtaining means. The value of one of the lateral acceleration sensors is acquired.

  The acceleration sensors 2 and 3 are installed on the rotation axis of the link motor 7, and the acceleration sensor 2 is installed at a position farther from the rotation center than the acceleration sensor 3. Since the inclination control ECU 30 controls the switching of the cut-off frequency based on the output of the acceleration sensor 2, the plurality of lateral acceleration sensors rotate at the center of rotation when the vehicle body is rotated to control the angle of the vehicle body. The responsiveness adjusting means obtains a value of a lateral acceleration sensor installed on a side far from the rotation center.

  The tilt control unit 33 acquires the lateral acceleration filtered by the low-pass filter of the acceleration filter unit 32, and the tilt control ECU 30 increases the responsiveness by increasing the cutoff frequency. Therefore, the angle control unit acquires the lateral acceleration. The lateral acceleration filtered by the low-pass filter of the means is acquired, and the responsiveness adjusting means increases the responsiveness of the angle control means by increasing the cutoff frequency of the low-pass filter.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Acceleration sensor 3 Acceleration sensor 5R, 5L Rear wheel 6R, 6L Travel drive motor 7 Link motor 8U, 8D Lateral link unit 9R, 9L Vertical link unit 10 Car body part 11 Storage 12 Throttle opening sensor 13 Steering angle sensor 14 Vehicle speed sensor 15 Front wheel 18 Center vertical member 20 Link mechanism 30 Inclination control ECU
31 Acceleration calculation unit 32 Acceleration filter unit 33 Tilt control unit 40 Tilt control ECU
41 Acceleration filter unit 42 Computation tilt control unit

Claims (8)

A pair of wheels;
A vehicle body having an adjustable angle with respect to a line segment connecting the centers of the pair of wheels;
Lateral acceleration acquisition means for acquiring lateral acceleration generated in the vehicle body;
An angle control means for controlling the angle of the vehicle body so that the acquired lateral acceleration becomes a predetermined target value;
Responsiveness adjusting means for increasing the responsiveness of the angle control means when the acquired lateral acceleration is equal to or greater than a predetermined threshold;
A vehicle characterized by comprising:   The vehicle according to claim 1, wherein the angle control means adjusts the angle of the vehicle body by inclining the pair of wheels.   The vehicle according to claim 1, wherein the angle control means adjusts the angle of the vehicle body by tilting the vehicle body with respect to the pair of wheels. A vehicle speed acquisition means for acquiring the vehicle speed;
The responsiveness adjusting means adjusts the responsiveness of the angle control means to a low value when the acquired vehicle speed is less than a predetermined threshold value, and the acquired lateral acceleration is adjusted to a predetermined threshold value during the low adjustment. 4. The vehicle according to claim 1, wherein the responsiveness of the angle control means is enhanced when the above is reached. The lateral acceleration acquisition means acquires a lateral acceleration and a combined lateral acceleration output by a plurality of lateral acceleration sensors,
The angle control means acquires the combined lateral acceleration from the lateral acceleration acquisition means,
The responsiveness adjusting means acquires the value of one of the plurality of lateral acceleration sensors from the lateral acceleration acquiring means. 5. Vehicle described in.   The plurality of lateral acceleration sensors are provided on one side of a rotation center when the vehicle body is rotated to control the angle of the vehicle body, and the responsiveness adjusting means is provided on a side far from the rotation center. The vehicle according to claim 5, wherein the value of the installed lateral acceleration sensor is acquired. The angle control means acquires the lateral acceleration filtered by the low-pass filter of the lateral acceleration acquisition means,
The responsiveness adjusting means increases the responsiveness of the angle control means by increasing a cutoff frequency of the low-pass filter, according to any one of claims 1 to 6. The vehicle described. A pair of wheels;
A vehicle body having an adjustable angle with respect to a line segment connecting the centers of the pair of wheels;
In a vehicle computer equipped with
A lateral acceleration acquisition function for acquiring lateral acceleration generated in the vehicle body;
An angle control function for controlling the angle of the vehicle body so that the acquired lateral acceleration becomes a predetermined target value;
A responsiveness adjusting function for increasing the responsiveness of the angle control function when the acquired lateral acceleration is a predetermined threshold value or more;
Vehicle control program that realizes

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