JP5045354B2 - vehicle - Google Patents

Description

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

  Conventionally, a technique related to a vehicle using posture control of an inverted pendulum has been proposed. For example, a vehicle having two drive wheels arranged on the same axis and driving by detecting a change in the posture of the vehicle body due to the driver's movement of the center of gravity, while controlling the posture of the vehicle body with a single spherical drive wheel Techniques for moving vehicles and the like have been proposed (see, for example, Patent Document 1).

In this case, the balance and operation state of the vehicle body is detected by a sensor, and the vehicle is stopped or moved by controlling the operation of the rotating body.
JP 2004-129435 A

  However, the conventional vehicle cannot maintain a stable traveling state or maintain a stable posture when it touches an obstacle during traveling. When a vehicle touches an obstacle, the observer, which is a means for estimating the slope of the road surface, may mistakenly recognize it as a slope and drive torque that pushes the obstacle may be added. . In this case, an obstacle or a vehicle body may be damaged.

  The present invention solves the problems of the conventional vehicle and recognizes the contact with the obstacle, and removes the error due to the contact with the obstacle from the estimated value of the road slope. By correcting the estimated value and preventing the wrong climbing torque from being applied, it is possible to realize a stable running state and stable attitude control even when touching an obstacle, and a highly safe vehicle The purpose is to provide.

  For this purpose, the vehicle of the present invention includes a drive wheel rotatably attached to the vehicle body, and a vehicle control device that controls a drive torque applied to the drive wheel to control the posture of the vehicle body, The vehicle control device includes a slope estimation unit that periodically estimates a road surface gradient, a contact identification unit that identifies whether or not the vehicle is in contact with an obstacle, and when the contact identification unit recognizes contact with the obstacle, the gradient And an estimated value correcting means for correcting the road gradient by removing an error due to contact with the obstacle from the road gradient estimated by the estimating means.

  In another vehicle of the present invention, the estimated value correcting means may further determine the road surface gradient estimated by the gradient estimating means before the contact with the obstacle when the contact identifying means recognizes contact with the obstacle. To the road gradient estimated by the gradient estimation means.

  In still another vehicle of the present invention, the vehicle control device further includes a gradient storage unit that stores the road surface gradient estimated by the gradient estimation unit, and the estimated value correction unit includes the obstacle identification unit as an obstacle. When the contact with the obstacle is recognized, the road gradient estimated by the gradient estimation unit is corrected to the road gradient stored by the gradient storage unit before the contact with the obstacle.

  In still another vehicle of the present invention, the gradient storage means always stores the road surface gradient estimated by the gradient estimation means within the latest past predetermined time.

  According to the configuration of claim 1, since the error due to the contact with the obstacle is removed from the estimated value, it is possible to prevent the wrong climbing torque from being applied and damage the obstacle or the vehicle. There is nothing.

  According to the second aspect of the present invention, since the original road surface gradient is estimated, the climbing torque is not lost even if it contacts an obstacle on the slope, so that the traveling on the climb can be continued.

  According to the configuration of the third aspect, since the estimated value of the road surface gradient before contact with the obstacle is used, the road surface gradient can be appropriately, reliably and easily corrected, and the safety of the vehicle is improved. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing the configuration of a vehicle in a first embodiment of the present invention, and shows a state in which an occupant is moving forward in an accelerated state, and FIG. 2 is a first embodiment of the present invention. 1 is a block diagram showing a configuration of a vehicle control system in FIG.

  In the figure, reference numeral 10 denotes a vehicle according to the present embodiment, which has a body portion 11, a driving wheel 12, a support portion 13, and a riding portion 14 on which an occupant 15 rides, and uses the posture control of an inverted pendulum. Control the attitude of the car body. The vehicle 10 can tilt the vehicle body forward and backward. In the example shown in FIG. 1, the vehicle 10 is accelerating in the direction indicated by the arrow A, and the vehicle body is tilted forward in the traveling direction.

  The drive wheel 12 is rotatably supported by a support portion 13 that is a part of the vehicle body, and is driven by a drive motor 52 as a drive actuator. The shaft of the drive wheel 12 extends in a direction perpendicular to the drawing of FIG. 1, and the drive wheel 12 rotates about the shaft. The drive wheel 12 may be singular or plural, but in the case of plural, the drive wheels 12 are arranged on the same axis in parallel. In the present embodiment, description will be made assuming that there are two drive wheels 12. In this case, each drive wheel 12 is independently driven by an individual drive motor 52. As the drive actuator, for example, a hydraulic motor, an internal combustion engine, or the like can be used, but here, the description will be made assuming that the drive motor 52 that is an electric motor is used.

  The main body 11 that is a part of the vehicle body is supported from below by the support 13 and is positioned above the drive wheels 12. And, in the main body part 11, the riding part 14 functioning as an active weight part can be translated relative to the main body part 11 in the longitudinal direction of the vehicle 10, in other words, the tangential direction of the vehicle body rotation circle It is attached so that it can move relatively.

  Here, the active weight portion has a certain amount of mass and translates with respect to the main body portion 11, that is, actively moves the front and rear to correct the position of the center of gravity of the vehicle 10. The active weight portion does not necessarily have to be the riding portion 14. For example, the active weight portion may be a device in which a heavy peripheral device such as a battery is attached to the main body portion 11 so as to be translatable. (Weight), a device in which a dedicated weight member such as a balancer is attached to the main body 11 so as to be translatable may be used. Moreover, you may use together the boarding part 14, a heavy peripheral device, an exclusive weight member, etc.

  In the present embodiment, for the sake of explanation, an example will be described in which the riding section 14 in a state in which the occupant 15 is boarded functions as an active weight section. However, the occupant 15 is not necessarily on the riding section 14. For example, when the vehicle 10 is operated by remote control, the occupant 15 may not be on the riding section 14, or cargo may be loaded instead of the occupant 15.

  The riding section 14 is the same as a seat used in automobiles such as passenger cars and buses, and includes a seat surface section 14a, a backrest section 14b, and a headrest 14c, and is attached to the main body section 11 through a moving mechanism (not shown). ing.

  The moving mechanism includes a low-resistance linear moving mechanism such as a linear guide device and an active weight part motor 62 as an active weight part actuator. The active weight part motor 62 drives the riding part 14, and the main body part 11. It is designed to move back and forth in the direction of travel. As the active weight actuator, for example, a hydraulic motor, a linear motor, or the like can be used. However, here, the description will be made assuming that the active weight motor 62 that is a rotary electric motor is used.

  The linear guide device includes, for example, a guide rail attached to the main body 11, a carriage attached to the riding part 14 and sliding along the guide rail, a ball, a roller, and the like interposed between the guide rail and the carriage. Rolling elements. In the guide rail, two track grooves are formed linearly along the longitudinal direction on the left and right side surfaces thereof. Moreover, the cross section of the carriage is formed in a U-shape, and two track grooves are formed on the inner sides of the two opposing side surfaces so as to face the track grooves of the guide rail. The rolling elements are incorporated between the raceway grooves, and roll in the raceway grooves with the relative linear motion of the guide rail and the carriage. The carriage is formed with a return passage that connects both ends of the raceway groove, and the rolling elements circulate through the raceway groove and the return passage.

  The linear guide device includes a brake or a clutch that fastens the movement of the linear guide device. When the operation of the riding section 14 is unnecessary, such as when the vehicle 10 is stopped, the relative positional relationship between the main body section 11 and the riding section 14 is maintained by fixing the carriage to the guide rail with a brake. . When the operation is necessary, the brake is released and the distance between the reference position on the main body 11 side and the reference position on the riding section 14 is controlled to be a predetermined value.

  An input device 30 including a joystick 31 as a target travel state acquisition device is disposed beside the boarding unit 14. The occupant 15 controls the vehicle 10 by operating a joystick 31 as a control device, that is, inputs a travel command such as acceleration, deceleration, turning, in-situ rotation, stop, and braking of the vehicle 10. ing. If the occupant 15 can operate and input a travel command, another device such as a jog dial, a touch panel, or a push button may be used as the target travel state acquisition device instead of the joystick 31. You can also.

  In addition, when the vehicle 10 is steered by remote control, it can replace with the said joystick 31, and can use the receiver which receives the driving | running | working command from a controller with a wire communication or a radio | wireless as a target driving state acquisition apparatus. Further, when the vehicle 10 automatically travels according to predetermined travel command data, a data reader that reads travel command data stored in a storage medium such as a semiconductor memory or a hard disk is used as a target travel instead of the joystick 31. It can be used as a status acquisition device.

  In addition, the vehicle 10 includes a control ECU (Electronic Control Unit) 20 as a vehicle control device, and the control ECU 20 includes a main control ECU 21, a drive wheel control ECU 22, and an active weight unit control ECU 23. The control ECU 20, main control ECU 21, driving wheel control ECU 22 and active weight unit control ECU 23 include calculation means such as a CPU and MPU, storage means such as a magnetic disk and semiconductor memory, input / output interfaces, and the like. A computer system that controls the operation. For example, the computer system is disposed in the main body 11, but may be disposed in the support portion 13 or the riding portion 14. The main control ECU 21, the drive wheel control ECU 22, and the active weight control ECU 23 may be configured separately or may be configured integrally.

  The main control ECU 21 functions as a part of the drive wheel control system 50 that controls the operation of the drive wheel 12 together with the drive wheel control ECU 22, the drive wheel sensor 51, and the drive motor 52. The drive wheel sensor 51 includes a resolver, an encoder, and the like, functions as a drive wheel rotation state measuring device, detects a drive wheel rotation angle and / or rotation angular velocity indicating a rotation state of the drive wheel 12, and transmits it to the main control ECU 21. To do. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22, and the drive wheel control ECU 22 supplies an input voltage corresponding to the received drive torque command value to the drive motor 52. The drive motor 52 applies drive torque to the drive wheels 12 in accordance with the input voltage, thereby functioning as a drive actuator.

  The main control ECU 21 functions as a part of the active weight part control system 60 that controls the operation of the riding part 14 that is the active weight part together with the active weight part control ECU 23, the active weight part sensor 61, and the active weight part motor 62. To do. The active weight part sensor 61 is composed of an encoder or the like, functions as an active weight part movement state measuring device, detects the active weight part position and / or movement speed indicating the movement state of the riding part 14, and transmits it to the main control ECU 21. To do. Further, the main control ECU 21 transmits an active weight part thrust command value to the active weight part control ECU 23, and the active weight part control ECU 23 sends an input voltage corresponding to the received active weight part thrust command value to the active weight part motor. 62. The active weight motor 62 applies thrust to the riding section 14 to translate the riding section 14 in accordance with the input voltage, thereby functioning as an active weight actuator.

  Further, the main control ECU 21 functions as a part of the vehicle body control system 40 that controls the posture of the vehicle body together with the drive wheel control ECU 22, the active weight unit control ECU 23, the vehicle body inclination sensor 41, the drive motor 52, and the active weight unit motor 62. . The vehicle body tilt sensor 41 includes an acceleration sensor, a gyro sensor, and the like, and functions as a vehicle body tilt state measuring device. The vehicle body tilt sensor 41 detects a vehicle body tilt angle and / or tilt angular velocity indicating the tilt state of the vehicle body, and transmits the detected vehicle body tilt angle to the main control ECU 21. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22 and transmits an active weight portion thrust command value to the active weight portion control ECU 23.

  The main control ECU 21 receives a travel command from the joystick 31 of the input device 30. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22 and transmits an active weight portion thrust command value to the active weight portion control ECU 23.

  Further, the control ECU 20 functions as a gradient estimation unit that estimates a road surface gradient based on a time change of the traveling state of the vehicle 10 and the vehicle body posture. Further, it functions as a target vehicle body posture determination means for determining a target vehicle body posture, that is, a vehicle body tilt state and / or an active weight portion movement state, according to the target travel state and the road surface gradient. Furthermore, it functions as an actuator output determining means that determines the output of each actuator according to the traveling state and vehicle body posture of the vehicle 10 acquired by each sensor, and the target traveling state, target vehicle body posture, and road gradient. Furthermore, it functions as road surface gradient acquisition means for acquiring the road surface gradient in the front-rear direction of the vehicle 10. Furthermore, it functions as a climbing torque determining means for determining the drive torque to be applied according to the road surface gradient. Furthermore, it functions as a center-of-gravity correction amount determining means for determining the center-of-gravity correction amount of the vehicle body according to the climbing torque.

  Each sensor may acquire a plurality of state quantities. For example, an acceleration sensor and a gyro sensor may be used in combination as the vehicle body tilt sensor 41, and the vehicle body tilt angle and the tilt angular velocity may be determined from both measured values.

  Next, the operation of the vehicle 10 configured as described above will be described. First, an outline of the travel and attitude control process will be described.

  FIG. 3 is a schematic diagram showing the operation of the vehicle on the slope in the first embodiment of the present invention, and FIG. 4 is a flowchart showing the operation of the vehicle running and attitude control processing in the first embodiment of the present invention. It is. FIG. 3A shows an example of operation according to the prior art for comparison, and FIG. 3B shows the operation according to the present embodiment.

  In the present embodiment, the riding section 14 functions as an active weight section, and as shown in FIG. 3 (b), the center of gravity of the vehicle 10 is actively moved by translating, that is, moving back and forth. It is to be corrected. Thereby, in order to stop the vehicle 10 on a slope, that is, even when the driving torque is applied to the driving wheels 12 so that the vehicle 10 does not move in the downward direction, The vehicle body does not tilt downward. Also, when traveling on a slope, the vehicle body does not tilt downward and can travel stably.

  On the other hand, if the center of gravity position correction according to the road surface gradient is not performed as in the conventional vehicle described in the section “Background Art”, the vehicle 10 is on a slope as shown in FIG. Since the reaction of the drive torque applied to the drive wheels 12 to stop the operation, that is, the reaction torque acts on the vehicle body, the vehicle body tilts downward. Even when traveling on a slope, it is not possible to perform stable vehicle body posture and travel control.

  Therefore, in the present embodiment, the vehicle 10 can stably stop and travel regardless of the road gradient by executing the travel and attitude control processing.

  In the running and posture control process, the control ECU 20 first executes a state quantity acquisition process (step S1), and the driving wheel is driven by each sensor, that is, the driving wheel sensor 51, the vehicle body tilt sensor 41, and the active weight sensor 61. 12 rotation states, vehicle body inclination states, and riding portion 14 movement states are acquired.

  Next, the control ECU 20 executes a road surface gradient acquisition process (step S2), and the state quantity acquired in the state quantity acquisition process, that is, the rotation state of the drive wheels 12, the inclination state of the vehicle body, and the movement of the riding section 14 are performed. Based on the state and the output values of the actuators, that is, the output values of the drive motor 52 and the active weight motor 62, the road surface gradient is estimated by the observer. Here, the observer is a method of observing the internal state of the control system based on a dynamic model, and is configured by wired logic or soft logic.

  Next, the control ECU 20 executes a target travel state determination process (step S3), and based on the operation amount of the joystick 31, the target value of the acceleration of the vehicle 10 and the target value of the rotational angular velocity of the drive wheels 12 are obtained. decide.

  Next, the control ECU 20 executes target body posture determination processing (step S4), and the road surface gradient acquired by the road surface gradient acquisition processing and the acceleration target of the vehicle 10 determined by the target travel state determination processing. Based on the value, a target value of the vehicle body posture, that is, a target value of the vehicle body inclination angle and the active weight portion position is determined.

  Finally, the control ECU 20 executes an actuator output determination process (step S5), and determines each state quantity acquired by the state quantity acquisition process, the road surface gradient acquired by the road surface gradient acquisition process, and the target travel state. Based on the target travel state determined by the processing and the target vehicle body posture determined by the target vehicle body posture determination process, the outputs of the actuators, that is, the outputs of the drive motor 52 and the active weight motor 62 are determined.

  Next, details of the traveling and attitude control processing will be described. First, the state quantity acquisition process will be described.

  FIG. 5 is a diagram showing a vehicle dynamic model and its parameters according to the first embodiment of the present invention, and FIG. 6 is a flowchart showing an operation of state quantity acquisition processing according to the first embodiment of the present invention.

In the present embodiment, state quantities and parameters are represented by the following symbols. FIG. 5 shows some of the state quantities and parameters.
θ _W : Drive wheel rotation angle [rad]
θ ₁ : Body tilt angle (vertical axis reference) [rad]
λ _S : Active weight part position (vehicle center point reference) [m]
τ _W : Driving torque (total of two driving wheels) [Nm]
S _S : Active weight part thrust [N]
g: Gravity acceleration [m / s ² ]
η: Road surface slope [rad]
m _W : Drive wheel mass (total of two drive wheels) [kg]
R _W : Driving wheel contact radius [m]
I _W : Moment of inertia of driving wheel (total of two driving wheels) [kgm ² ]
D _W : viscosity damping coefficient [Nms / rad] for driving wheel rotation
m ₁ : Body mass (including active weight) [kg]
l ₁ : Body center-of-gravity distance (from axle) [m]
I ₁ : Body inertia moment (around the center of gravity) [kgm ² ]
D ₁ : Viscous damping coefficient for vehicle body tilt [Nms / rad]
m _S : Active weight part mass [kg]
l _S : Active weight part center of gravity distance (from axle) [m]
I _S : Active weight part inertia moment (around the center of gravity) [kgm ² ]
D _S : Viscous damping coefficient [Nms / rad] for active weight translation

  Next, the road surface gradient acquisition process will be described.

  FIG. 7 is a flowchart showing the operation of the road surface gradient acquisition process in the first embodiment of the present invention.

  In the road surface gradient acquisition process, the main control ECU 21 estimates the road surface gradient η (step S2-1). In this case, based on each state quantity acquired in the state quantity acquisition process and the output of each actuator determined in the actuator output determination process in the previous run (previous time step) travel and posture control process, The road surface gradient η is estimated from equation (1).

  As described above, in the present embodiment, the road surface gradient is estimated based on the driving torque output from the driving motor 52 and the driving wheel rotation angular acceleration, the vehicle body inclination angular acceleration, and the active weight moving acceleration as the state quantities. . In this case, not only the driving wheel rotation angular acceleration indicating the rotation state of the driving wheel 12, but also the vehicle body inclination angular acceleration and the active weight moving acceleration indicating the vehicle body posture change are taken into consideration. That is, a change in the posture of the vehicle body, which is an element peculiar to the so-called inverted vehicle using the posture control of the inverted pendulum, is taken into consideration.

  Conventionally, since the road surface gradient is estimated based on the driving torque and the driving wheel rotation angular acceleration, a large error may occur in the estimated value of the road surface gradient particularly when the posture of the vehicle body is changing. However, in the present embodiment, the road surface gradient is estimated in consideration of the vehicle body inclination angle acceleration indicating the posture change of the vehicle body and the active weight portion movement acceleration, so that no large error occurs and the road surface is extremely accurate. The gradient can be estimated.

  Generally, in an inverted type vehicle, the center of gravity of the vehicle body moves back and forth relative to the drive wheels, so that the center of gravity of the vehicle may move back and forth even when the drive wheels are stopped. Therefore, in order to estimate the road gradient with high accuracy from the acceleration of the center of gravity and the driving force or the driving torque, it is necessary to consider such influence. In a general inverted type vehicle, since the weight ratio of the vehicle body to the entire vehicle is high, such an influence becomes large particularly when the vehicle is stopped.

  Note that the high-frequency component of the estimated value can be removed by applying a low-pass filter to the road surface gradient value. In this case, a time delay occurs in the estimation, but the vibration caused by the high frequency component can be suppressed.

  In the present embodiment, the gravitational component due to the driving force, inertial force, and road surface gradient is taken into consideration, but the rolling resistance of the driving wheel 12, the viscous resistance due to the friction of the rotating shaft, the air resistance acting on the vehicle 10, etc. May be considered as a side effect.

  In the present embodiment, a linear model related to the rotational motion of the drive wheel 12 is used. However, a more accurate nonlinear model may be used, or a model for vehicle body tilting motion or active weight portion translational motion. May be used. For nonlinear models, functions can also be applied in the form of maps.

  Further, in order to simplify the calculation, it is not necessary to consider the change in the body posture.

  Next, the target travel state determination process will be described.

  FIG. 8 is a flowchart showing the operation of the target travel state determination process in the first embodiment of the present invention.

  In the determination process of the target travel state, the main control ECU 21 first acquires a steering operation amount (step S3-1). In this case, the occupant 15 acquires the operation amount of the joystick 31 that is operated to input a travel command such as acceleration, deceleration, turning, on-site rotation, stop, and braking of the vehicle 10.

  Subsequently, the main control ECU 21 determines a target value for vehicle acceleration based on the acquired operation amount of the joystick 31 (step S3-2). For example, a value proportional to the amount of operation of the joystick 31 in the front-rear direction is set as a target value for vehicle acceleration.

Subsequently, the main control ECU 21 calculates the target value of the drive wheel rotational angular velocity from the determined target value of the vehicle acceleration (step S3-3). For example, by integrating the target value of the vehicle acceleration time, a value obtained by dividing the driving wheel contact radius R _W and the target value of the drive wheel rotation angular velocity.

  Next, the target vehicle body posture determination process will be described.

  FIG. 9 is a graph showing changes in the target value of the active weight portion position and the target value of the vehicle body tilt angle in the first embodiment of the present invention, and FIG. 10 shows the target vehicle body posture in the first embodiment of the present invention. It is a flowchart which shows the operation | movement of a determination process.

  In the target body posture determination process, the main control ECU 21 first determines the target value of the active weight portion position and the target value of the vehicle body tilt angle (step S4-1). In this case, based on the target value of the vehicle acceleration determined by the target travel state determination process and the road surface gradient η acquired by the road surface gradient acquisition process, the active weight is calculated by the following equations (2) and (3). The target value of the part position and the target value of the vehicle body inclination angle are determined.

  Subsequently, the main control ECU 21 calculates the remaining target value (step S4-2). That is, the target values of the drive wheel rotation angle, the vehicle body inclination angular velocity, and the active weight portion moving speed are calculated by time differentiation or time integration of each target value.

  As described above, in the present embodiment, not only the inertial force and drive motor reaction torque acting on the vehicle body in accordance with the vehicle acceleration, but also the reaction torque acting on the vehicle body in accordance with the climbing torque according to the road surface gradient η is considered. Thus, the target value of the vehicle body posture, that is, the target value of the active weight portion position and the target value of the vehicle body tilt angle are determined.

  At this time, the center of gravity of the vehicle body is moved so that the torque that acts on the vehicle body to tilt the vehicle body, that is, the vehicle body tilt torque is canceled out by the action of gravity. For example, when the vehicle 10 accelerates and climbs a hill, the riding section 14 is moved forward, or the vehicle body is further tilted forward. Further, when the vehicle 10 decelerates and goes down a hill, the riding section 14 is moved backward, or the vehicle body is further tilted backward.

  In the present embodiment, as shown in FIG. 9, first, the riding section 14 is moved without tilting the vehicle body, and when the riding section 14 reaches the active weight movement limit, the tilting of the vehicle body is started. . For this reason, the vehicle body does not tilt forward and backward with respect to fine acceleration / deceleration, so that the ride comfort for the occupant 15 is improved. Further, if the slope is not particularly steep, the vehicle body is kept upright even on a slope, so that it is easy to ensure visibility for the occupant 15. Furthermore, if the slope is not particularly steep, the vehicle body will not be greatly inclined even on a slope, so that a part of the vehicle body is prevented from coming into contact with the road surface.

  In the present embodiment, it is assumed that the active weight part movement limit is equal between the front and the rear, but when the front and rear are different, the inclination of the vehicle body is changed according to each limit. The presence or absence may be switched. For example, when the braking performance is set higher than the acceleration performance, it is necessary to set the rear active weight portion movement limit farther than the front.

  In this embodiment, when the acceleration is low or the gradient is gentle, only the movement of the riding section 14 is used, but some or all of the vehicle body tilt torque is handled by the vehicle body tilt. Also good. By tilting the vehicle body, the longitudinal force acting on the occupant 15 can be reduced.

  Further, in the present embodiment, an expression based on a linearized dynamic model is used, but an expression based on a more accurate nonlinear model or a model considering viscous resistance may be used. Note that if the equation is nonlinear, the function can be applied in the form of a map.

  Next, the actuator output determination process will be described.

  FIG. 11 is a flowchart showing the operation of the actuator output determination process in the first embodiment of the present invention.

  In the actuator output determination process, the main control ECU 21 first determines the feedforward output of each actuator (step S5-1). In this case, the feedforward output of the drive motor 52 is determined from each target value and the road surface gradient η by the following equation (4), and the feedforward output of the active weight motor 62 is also obtained by the following equation (5). To decide.

  In this way, by automatically adding a climbing torque according to the road surface gradient η, that is, by correcting the driving torque according to the road surface gradient η, the same steering sensation as on a flat ground can be obtained. Can be provided. That is, even if the occupant 15 releases his / her hand from the joystick 31 after stopping on a slope, the vehicle 10 does not move. Even on a slope, acceleration / deceleration similar to that on a flat ground can be performed for a certain steering operation of the joystick 31.

  Thus, in the present embodiment, more accurate control is realized by theoretically giving a feedforward output.

  Note that the feedforward output can be omitted as necessary. In this case, the feedback control indirectly gives a value close to the feedforward output with a steady deviation. Further, the steady deviation can be reduced by applying an integral gain.

  Subsequently, the main control ECU 21 determines the feedback output of each actuator (step S5-2). In this case, the feedback output of the drive motor 52 is determined from the deviation between each target value and the actual state quantity by the following equation (6), and the feedback of the active weight motor 62 is also obtained by the following equation (7). Determine the output.

Note that nonlinear feedback control such as sliding mode control can also be introduced. As simpler control, some of the feedback gains excluding K _W2 , K _W3, and K _S5 may be set to zero. Further, an integral gain may be introduced in order to eliminate the steady deviation.

  Finally, the main control ECU 21 gives a command value to each element control system (step S5-3). In this case, the main control ECU 21 transmits the sum of the feedforward output and the feedback output determined as described above to the drive wheel control ECU 22 and the active weight part control ECU 23 as the drive torque command value and the active weight part thrust command value. .

  As described above, in the present embodiment, the road surface gradient η is estimated by the observer, the climbing torque is applied, and the riding section 14 is moved upward. Therefore, the vehicle body can be held upright on a slope and can cope with a steep slope. Further, an apparatus for measuring the road surface gradient η is not required, and the structure can be simplified and the cost can be reduced.

Further, since the road surface gradient η is estimated in consideration of the vehicle body inclination angle θ ₁ indicating the vehicle body posture and the active weight portion position λ _S , the road surface gradient η can be estimated with extremely high accuracy without causing a large error. Can do.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 12 is a flowchart showing the operation of target travel state determination processing in the second embodiment of the present invention.

  In the first embodiment, the road surface gradient is measured by the observer based on the rotation state of the drive wheel 12, the inclination state of the vehicle body, the movement state of the riding portion 14, and the output values of the drive motor 52 and the active weight portion motor 62. Is estimated. When the vehicle body comes into contact with the obstacle, the observer may misrecognize it as a slope, and a driving torque that pushes the obstacle may be added. Therefore, when a vehicle body contacts an obstacle, an obstacle or a vehicle body may be damaged.

  In general, the road surface gradient is estimated from the inertial force (acceleration of the center of gravity of the vehicle body) acting on the vehicle body and the magnitude of the driving force. Specifically, considering the component parallel to the road surface of the vehicle motion, it is assumed that the external force that balances the inertial force acting on the vehicle body is composed only of the component parallel to the driving force and the gravity road surface acting on the vehicle body The road surface gradient is estimated based on At this time, when an external force other than gravity, for example, a reaction force from an obstacle when in contact with an obstacle is applied, the means for estimating the road surface gradient uses the reaction force as a function of gravity, that is, a large road surface in the upward direction. Recognize that this is due to a gradient. And since the climbing torque according to the recognized road surface gradient is added, the vehicle 10 will perform the operation | movement which pushes an obstruction.

  Therefore, in the present embodiment, the contact with the obstacle is identified based on the estimated value of the road surface gradient and the time change of the vehicle speed. Specifically, it is determined whether or not the vehicle is in contact with the obstacle by comparing with an estimated value of the road surface gradient when the vehicle is in contact with the obstacle and a typical pattern of the vehicle speed.

  And when it is judged that it is a contact with an obstruction, the estimated value of a road surface gradient is corrected. In addition, the vehicle acceleration target value is limited to prevent driving toward an obstacle.

  For this purpose, the control ECU 20 as a vehicle control device includes a slope estimation unit that estimates a road surface gradient, a contact identification unit that identifies whether or not the vehicle is in contact with an obstacle, a gradient storage unit that stores a road surface gradient, and a road surface gradient. It functions as an estimated value correcting means for correcting. The main control ECU 21 repeats the above-described operation at a predetermined cycle, for example, every 100 [μsec], and periodically estimates the road surface gradient.

  As a result, a stable running state and stable posture control can be realized even when touching an obstacle. And the safety | security of the vehicle 10 can further be improved.

  Note that the configuration of the vehicle 10 in the present embodiment is the same as that in the first embodiment, and thus the description thereof is omitted.

  Next, details of the traveling and posture control processing in the present embodiment will be described. The state quantity acquisition process, the road surface gradient acquisition process, the target vehicle body posture determination process, and the actuator output determination process are the same as those in the first embodiment, and thus the description thereof is omitted. Only the determination process will be described.

  In the target travel state determination process, the main control ECU 21 first acquires a steering operation amount (step S3-11). In this case, the occupant 15 acquires the operation amount of the joystick 31 that is operated to input a travel command such as acceleration, deceleration, turning, on-site rotation, stop, and braking of the vehicle 10.

  Subsequently, the main control ECU 21 determines a target value of vehicle acceleration based on the acquired operation amount of the joystick 31 (step S3-12). For example, a value proportional to the amount of operation of the joystick 31 in the front-rear direction is set as a target value for vehicle acceleration.

  Subsequently, the main control ECU 21 executes obstacle contact determination and response control processing (step S3-13), determines whether or not the obstacle is in contact with the obstacle, and if the obstacle is in contact with the obstacle. The estimated value of the road surface gradient and the target value of the vehicle acceleration are corrected.

Subsequently, the main control ECU 21 calculates the target value of the drive wheel rotation angular velocity from the determined target value of the vehicle acceleration (step S3-14). For example, by integrating the target value of the vehicle acceleration time, a value obtained by dividing the driving wheel contact radius R _W and the target value of the drive wheel rotation angular velocity.

  Next, obstacle contact determination and response control processing will be described.

  FIG. 13 is a diagram showing a typical pattern of a temporal change in the estimated value of the road surface gradient at the time of obstacle contact according to the second embodiment of the present invention, and FIG. 14 is an obstacle contact according to the second embodiment of the present invention. FIG. 15 is a flowchart showing the operation of obstacle contact determination and response control processing in the second embodiment of the present invention.

  In the obstacle contact determination and response control process, the main control ECU 21 first determines whether or not the second flag (flag2) is on, that is, whether or not flag2 = 1 (step S3-13-). 1).

  The second flag is a flag indicating the execution state of the obstacle contact determination, and the second flag ON (flag2 = 1) indicates that the obstacle contact handling process is being executed, and the second flag OFF (flag2 = 0) The state of) indicates that the obstacle contact handling process is not executed.

The second flag is managed by a contact determination valid timer. The contact determination valid timer is a timer that measures the time t ₂ from the time when the contact state end determination time, that is, the time when the state is estimated to have been canceled after the vehicle 10 has touched the obstacle to the present, and the contact determination is valid. when the measured time t ₂ of the contact determination effective timer is below a predetermined value, to turn on the second flag. That is, the fact that the second flag is on means that it is within a fixed time since it is determined that the contact state has ended in the previous obstacle contact determination and response control processing.

  If the second flag is not on, that is, if it has never been determined that the vehicle is in the obstacle contact state, or after determining that the contact state has ended in the previous obstacle contact determination and response control processing. Only when a certain time or more has elapsed, the main control ECU 21 executes the determination of the first condition in the obstacle contact determination (step S3-13-2).

  The first condition is dynamic contact determination based on a road surface gradient change rate, and whether or not the absolute value of the change rate of the estimated value of the road surface gradient is larger than a preset first threshold value of contact determination, that is, Judgment is made based on whether or not equation (8) is established.

  FIG. 13 shows a typical temporal change pattern of the estimated value of the road surface gradient when the vehicle 10 comes into contact with an obstacle and ascends a slope. In FIG. 13, the solid line indicates the time change of the estimated value of the road surface gradient when contacting the obstacle, and the dotted line indicates the time change of the estimated value of the road surface gradient when going up the hill. A sudden change in the estimated value immediately after the obstacle contact, which is one of the characteristic differences between the two, is captured by the first condition.

The main control ECU 21 determines that there is a possibility of contact with an obstacle when the absolute value of the road surface slope change rate is greater than the first threshold value for contact determination, and sets the measurement time t ₁ of the dynamic contact determination effective timer to zero. (T ₁ = 0), the first flag (flag 1) is turned on (flag 1 = 1), and the dynamic contact determination valid timer is activated (step S3-13-3).

  The first flag is a flag indicating the execution state of the obstacle static contact determination process, and the state of the first flag on (flag1 = 1) indicates that the obstacle static contact determination process is being executed. Flag off (flag1 = 0) indicates that the obstacle static contact determination processing is not executed.

The first flag is managed by a dynamic contact determination valid timer. The dynamic contact determination valid timer is a timer for measuring t ₁ from a dynamic contact state end determination time, that is, a time from the time when the vehicle 10 is estimated to be in the dynamic contact state according to the first condition to the present time. When the measurement time t ₁ of the dynamic contact determination valid timer is less than or equal to a predetermined value, the first flag is turned on. That is, resetting to zero and turning on the first flag means starting the measurement of the elapsed time after the end of the dynamic contact state.

  Subsequently, the main control ECU 21 executes the determination of the second condition in the obstacle contact determination (step S3-13-4). The second condition is a static contact determination based on the driving wheel rotational angular velocity deviation, and whether or not the absolute value of the difference between the actual value of the driving wheel rotational angular velocity and the target value is greater than a preset second threshold value of the contact determination. That is, the determination is made based on whether or not the following equation (9) holds.

  When the second flag is on at the beginning of the obstacle contact determination and response control process, that is, within a certain time after determining that the contact state has ended, the main control ECU 21 determines the obstacle contact determination. The determination of the second condition in the obstacle contact determination is immediately executed without executing the determination of the first condition.

  FIG. 14 shows a typical temporal change pattern of the drive wheel rotation angle when the vehicle 10 comes into contact with an obstacle and ascends a hill. In FIG. 14, the solid line shows the time change of the drive wheel rotation angular velocity when contacting the obstacle, and the dotted line shows the time change of the drive wheel rotation angular velocity when going up the slope. A sudden change in the rotational speed (vehicle speed) of the driving wheel at the time of obstacle contact, which is one of the characteristic differences between the two, is captured by the second condition.

  The main control ECU 21 determines that there is a high possibility of contact with an obstacle when the absolute value of the driving wheel rotation angular velocity deviation is greater than the second threshold value for contact determination, and executes the determination of the third condition in the obstacle contact determination. (Step S3-13-5). The third condition is a static contact determination based on a road surface gradient change amount, and whether or not the absolute value of the road surface gradient change amount is larger than a preset third threshold value of the contact determination, that is, the following equation (10 ) Is determined based on whether or not.

Then, reset the main control ECU21, when larger than the third threshold value of the absolute value of the contact determination of the road surface slope change amount is determined to be in contact with the obstacle, the measurement time t ₂ of the contact determination effective timer to zero (T ₂ = 0), the second flag is turned on (flag2 = 1), and the contact determination valid timer is activated (step S3-13-6). Turning on the second flag resets the measured time t ₂ to zero means that the contact state starts to measure the elapsed time from completion.

  Subsequently, the main control ECU 21 executes an obstacle contact handling control process (step S3-13-7) and ends the process. The estimated value of the road surface gradient and the target value of the vehicle acceleration are corrected by the obstacle contact handling control process.

  On the other hand, in the determination of the first condition in the obstacle contact determination, when the absolute value of the road surface gradient change rate is equal to or smaller than the first threshold value of the contact determination, the main control ECU 21 determines that the vehicle 10 is not currently in the dynamic contact state. Next, it is determined whether or not the first flag is on, that is, whether or not flag1 = 1 (step S3-13-8).

And only when the first flag is not on, that is, when it has never been determined that the vehicle is in the obstacle dynamic contact state, or when a certain time or more has passed since the end of the dynamic contact state determination, The main control ECU 21 ends the process as it is. When the first flag is on, that is, within a certain period of time immediately after the dynamic contact state end determination, the main control ECU 21 increases the measurement time of the dynamic contact determination valid timer by Δt (step S3- 13-9), that is, the measurement time t ₁ is replaced with t ₁ + Δt (t ₁ ← t ₁ + Δt).

Subsequently, the main control ECU 21 determines whether or not the measurement time t ₁ of the dynamic contact determination effective timer has passed a predetermined time T _{1, Max} (t ₁ > T _{1, Max} ) (step S3-13-). 10). The dynamic contact determination enable the timed time of the timer t ₁ is a predetermined time T _1, when _Max or less, the main control ECU21 executes the determination of the second condition in the obstacle contact determination. Further, when the measurement time t ₁ of the dynamic contact determination enable timer has passed a predetermined time T _{1, Max,} the main control ECU21 includes a first flag in the OFF (flag1 = 0) (step S3-13- 11) The process is terminated.

  On the other hand, in the determination of the second condition in the obstacle contact determination, when the absolute value of the driving wheel rotation angular velocity deviation is equal to or less than the preset second threshold value of the contact determination, and in the determination of the third condition in the obstacle contact determination When the absolute value of the road surface gradient change amount is equal to or smaller than a preset third threshold value for contact determination, the main control ECU 21 determines that the vehicle 10 is not currently in contact, and then the second flag is on. Whether or not flag2 = 1 is determined (step S3-13-12).

When the second flag is not on, that is, when it has never been determined that the vehicle is in the obstacle contact state, or when a certain period of time has elapsed immediately after the contact state end determination, the main control ECU 21 The processing is terminated while the 1 flag is kept on. When the second flag is on, that is, within a certain time immediately after the contact state end determination, the main control ECU 21 increases the measurement time of the contact determination valid timer by Δt (step S3-13-13). That is, the measurement time t ₂ is replaced with t ₂ + Δt (t ₂ ← t ₂ + Δt).

Subsequently, the main control ECU21, the measurement time t ₂ of the contact determination effective timer has exceeded the predetermined time _{T 2, Max (t 2>} T 2, Max) determines whether (step S3-13-14) . Then, when the measured time t ₂ of the contact determination effective timer is equal to or less than a predetermined time T _{2, Max,} the main control ECU21, the second condition, or, even if not satisfy the third condition, the obstacle contacts the corresponding control Execute the process and end the process. Further, when the measurement time t ₂ of the contact determination effective timer has passed a predetermined time T _{2, Max,} the main control ECU21 is in the first flag and second flag off (flag1 = 0, flag2 = 0 ) (Step S3-13-15), the process ends.

  Thus, in the obstacle contact determination, the first condition is determined, and then the second condition and the third condition are determined. That is, the dynamic contact determination based on the road surface gradient change rate is performed, and then the static contact determination based on the driving wheel rotation angular velocity deviation and the static contact determination based on the road surface gradient change amount are performed. Then, paying attention to the estimated value of the road surface gradient when touching the obstacle and the time change of the driving wheel rotation angular velocity, these values and the aspect of the time change are similar to the typical pattern when touching the obstacle. The vehicle 10 is in contact with the obstacle.

  In the operation of the obstacle contact determination and response control process according to the flowchart shown in FIG. 15, it is determined that an obstacle has been touched when all of the first condition, the second condition, and the third condition are satisfied.

As described above, the first condition is dynamic contact determination based on the road surface gradient change rate. When the vehicle 10 comes into contact with an obstacle at a certain speed, the estimated value of the road gradient increases rapidly by misrecognizing the reaction force as the action of gravity. Also, when an acceleration command is received in a stopped state in contact with an obstacle, the estimated value of the reaction force and road surface gradient increases rapidly together with the driving torque necessary for acceleration. Therefore, when the absolute value of the rate of change of the estimated value of the road surface gradient exceeds the first threshold value for contact determination, it is determined that there is a possibility that the object has touched the obstacle, and at a certain time T1 _{, Max after} that, The determination of the second condition and the third condition is executed.

  As described above, the second condition is a static contact determination based on the driving wheel rotation angular velocity deviation. When it comes into contact with an obstacle, the traveling speed of the vehicle 10 decreases compared to the target traveling speed due to the reaction force from the obstacle. Further, even when an acceleration command is received in a stopped state in contact with an obstacle, the vehicle cannot be accelerated to the target traveling speed. Therefore, when the difference between the actual value of the driving wheel rotational angular velocity and the target value, that is, the absolute value of the driving wheel rotational angular velocity deviation exceeds the second threshold value for contact determination, it is highly likely that the vehicle has touched the obstacle. Next, the third condition is determined.

As described above, the third condition is a static contact determination based on the road surface gradient change amount. When the vehicle 10 comes into contact with the obstacle, the reaction force from the obstacle acts on the vehicle 10 according to the climbing torque (driving torque of the driving wheels 12) with respect to the erroneously estimated road surface gradient. Keep a high value. Therefore, the difference between the estimated value of the road surface gradient at time t ₀ before the contact with the obstacle and the estimated value of the current road surface gradient, that is, the absolute value of the change amount of the estimated value of the road surface gradient is the third threshold value for contact determination. If it exceeds, it is determined that an obstacle has been touched.

And when it determines with having touched the obstruction, subsequent fixed time T2 _{, Max} does not change the determination. Thereby, the vibration (chattering) resulting from the switching of control can be prevented.

  Here, an example has been described in which contact with an obstacle is identified when all of the first condition, the second condition, and the third condition are satisfied, that is, it is determined that the object is in contact with the obstacle. If any one or two of the condition, the second condition, and the third condition are satisfied, it may be determined that the obstacle has been touched. For example, when either the second condition or the third condition and the first condition are satisfied, it may be determined that an obstacle has been touched. Further, even if the second condition and the third condition are not satisfied, it may be determined that the obstacle has been touched if only the first condition is satisfied.

  Furthermore, the obstacle contact determination can be executed by adding conditions other than the first condition, the second condition, and the third condition. For example, by adding a condition that it is determined that the vehicle has touched an obstacle when the temporal change rate of the drive wheel rotation angular velocity deviation or the vehicle body tilt angular velocity deviation exceeds a predetermined threshold, the false recognition rate of the contact state is further reduced. can do.

  Moreover, although the example which performs determination about each condition with the preset threshold value was demonstrated, a threshold value can also be changed according to the driving | running | working state of the vehicle 10. FIG. For example, by increasing the vehicle running speed before contacting an obstacle and increasing the road gradient change rate and driving wheel rotation angular speed deviation threshold, a determination suitable for the actual mechanical condition is made, and more accurate Recognition can be realized.

  Moreover, although the example which evaluates the grade of the speed which the estimated value of a road surface gradient changes with a difference was demonstrated, the component of a certain frequency band may be extracted with a frequency filter, and you may determine based on the magnitude. For example, more accurate recognition can be realized by ignoring a gradual change in the low-frequency band using a band-pass filter and removing high-frequency components due to road surface irregularities and sensor signal noise.

  Next, the obstacle contact handling control process will be described.

  FIG. 16 is a flowchart showing the operation of the obstacle contact handling control process in the second embodiment of the present invention.

In the obstacle contact handling control process, the main control ECU 21 first corrects the target value α ^* of the vehicle acceleration in accordance with the sign of the estimated road surface gradient (step S3-13-7-1). In other words, the vehicle acceleration target value α ^* is limited so that the vehicle 10 cannot be accelerated toward the obstacle.

Subsequently, the main control ECU 21 corrects the estimated value of the road surface gradient including an error due to obstacle contact (step S3-13-7-2). That is, the estimated value η (t ₀ ) of the road surface gradient at time t = t _0, which is a predetermined time before the obstacle dynamic contact determination based on the road surface gradient change rate, is used as the current road surface gradient estimated value.

  Thereby, even when the vehicle 10 comes into contact with an obstacle, a stable traveling state and stable posture control can be realized.

As described above, in this embodiment, when contact with an obstacle is identified, the estimated value of the road surface gradient is corrected to prevent an incorrect target value of the climbing torque or the vehicle body posture from being given. Specifically, as described above, the estimated value η (t ₀ ) of the road surface gradient at time t = t _0, which is a predetermined time before the dynamic contact determination based on the road surface gradient change rate, is the estimated value of the current road surface gradient. And As a result, the error due to contact with the obstacle is removed, but the part due to the original road gradient remains, so even if it touches the obstacle on the slope, it is necessary to climb and climb The vehicle 10 can maintain a stable state without losing torque. In addition, the history of the estimated value of the road surface gradient at a predetermined time is always stored so that the estimated value of the road surface gradient before the contact with the obstacle can be referred to.

Further, the estimated value of the road surface gradient is corrected, and the target value α ^* of the vehicle acceleration requested by the occupant 15 is limited. In other words, the vehicle acceleration target value α ^* is limited so that the vehicle 10 cannot be accelerated toward the obstacle. Specifically, when the difference from the estimated value of the road surface gradient before correction is positive, that is, when the obstacle is ahead, the target value α ^* of the vehicle acceleration is set to zero or less. Further, when the difference from the estimated value of the road surface gradient before correction is negative, that is, when the obstacle is behind, the vehicle acceleration target value α ^* is set to zero or more. Thereby, the deterioration of the state resulting from the unrecognized obstacle or the erroneous operation of the occupant 15 can be prevented, and the safety of the vehicle 10 can be further improved.

  In the present embodiment, only the target value of the vehicle acceleration is limited, but the target value of the vehicle speed may be limited. For example, when the vehicle touches an obstacle in front of the vehicle, the target speed of the vehicle may be limited to zero or less. In this case, the vehicle 10 automatically stops suddenly.

  Moreover, you may add and perform other control at the time of a contact determination with an obstruction. For example, a warning sound or warning display may be given to the occupant 15 to call attention. In addition, a time schedule of the target value of the drive wheel rotation angular velocity may be given so that the vehicle 10 automatically leaves the obstacle, for example, so that the vehicle 10 automatically falls slightly later and stops.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

It is the schematic which shows the structure of the vehicle in the 1st Embodiment of this invention, and is a figure which shows the state which is carrying out acceleration advance in the state which the passenger | crew got on. It is a block diagram which shows the structure of the control system of the vehicle in the 1st Embodiment of this invention. It is the schematic which shows the operation | movement of the vehicle on the slope in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the driving | running | working and attitude | position control processing of the vehicle in the 1st Embodiment of this invention. It is a figure which shows the dynamic model of the vehicle in the 1st Embodiment of this invention, and its parameter. It is a flowchart which shows the operation | movement of the acquisition process of the state quantity in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the acquisition process of the road surface gradient in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the target driving state in the 1st Embodiment of this invention. It is a graph which shows the change of the target value of the active weight part position in the 1st Embodiment of this invention, and the target value of a vehicle body tilt angle. It is a flowchart which shows the operation | movement of the determination process of the target vehicle body attitude | position in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the actuator output in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the target driving state in the 2nd Embodiment of this invention. It is a typical pattern of the time change of the estimated value of a road surface gradient at the time of obstacle contact in the 2nd embodiment of the present invention. It is a figure which shows the typical pattern of the time change of a driving wheel rotational angular velocity at the time of the obstruction contact in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the obstruction contact determination in the 2nd Embodiment of this invention, and a response control process. It is a flowchart which shows the operation | movement of the obstacle contact corresponding | compatible control process in the 2nd Embodiment of this invention.

Explanation of symbols

10 Vehicle 12 Drive wheel 20 Control ECU

Claims (3)

A drive wheel rotatably mounted on the vehicle body,
A vehicle control device for controlling the attitude of the vehicle body by controlling the drive torque applied to the drive wheels,
The vehicle control device
A slope estimating means for estimating a road surface slope;
Contact identification means for identifying whether or not an obstacle has been contacted;
When the contact recognition means recognizes a contact with an obstacle, and characterized in that it comprises the estimated value correction means for correcting the road surface gradient the gradient estimating means has estimated road surface gradient is estimated prior to contact with the obstacle Vehicle. The vehicle control device includes a gradient storage unit that stores the road surface gradient estimated by the gradient estimation unit,
When the contact identifying unit recognizes contact with an obstacle, the estimated value correcting unit converts the road surface gradient estimated by the gradient estimating unit into a road surface gradient stored by the gradient storage unit before contact with the obstacle. The vehicle according to claim 1 to be corrected.   The vehicle according to claim 2, wherein the gradient storage unit always stores a road surface gradient estimated by the gradient estimation unit within a predetermined past time.

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