JP2012121571A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly keep the balance by limiting target acceleration of a vehicle in accordance with a road surface gradient without bringing a vehicle body into contact with a road surface even in a hill, and to achieve a stable vehicle travel condition irrespective of the road surface gradient.SOLUTION: The vehicle includes a drive wheel 12 rotatably mounted on a vehicle body and a vehicle control device controlling drive torque applied to the drive wheel 12 and controlling the posture of the vehicle body. The vehicle control device limits a target value of vehicle acceleration in accordance with a road surface gradient, and sets the limit value of the target value of the vehicle acceleration on the basis of at least one of a limit value corresponding to the vehicle body grounding and a limit value corresponding to the maximum value of the drive torque.

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 stopped state on a slope or travel stably. For example, when accelerating or decelerating, the vehicle body is tilted back and forth to maintain balance. May end up. Further, if the inclination angle of the vehicle body is limited so that the vehicle body does not contact the road surface, it becomes impossible to maintain the balance of the vehicle body with respect to the inertial force and counter-torque accompanying acceleration and deceleration.

  The present invention solves the problems of the conventional vehicle and limits the target acceleration of the vehicle according to the road gradient, so that the vehicle body does not come into contact with the road surface even on a slope. It is an object of the present invention to provide a highly practical vehicle that can maintain a good balance and can realize a stable traveling state of the vehicle regardless of the road surface gradient.

  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 limits the target value of the vehicle acceleration according to the road surface gradient, and the limit value of the target value of the vehicle acceleration corresponds to the limit value corresponding to the vehicle ground contact and the maximum value of the driving torque. It is set based on at least one of the limit value.

  In another vehicle of the present invention, the vehicle control device further includes a value obtained by subtracting a value proportional to the road surface gradient from an absolute value of a limit value corresponding to vehicle body grounding when the road surface gradient is zero, and a road surface The value obtained by subtracting the value proportional to the road surface gradient from the absolute value of the limit value corresponding to the maximum value of the drive torque when the gradient is zero corresponds to the limit value corresponding to the vehicle ground contact and the maximum value of the drive torque. Limit value.

  Still another vehicle according to the present invention further includes an active weight portion movably attached to the vehicle body, and the vehicle control device sets a limit value corresponding to the vehicle body grounding to a rotation value of the vehicle body. It sets based on at least one of the maximum value of the inclination angle by movement, and the maximum value of the movement amount of the said active weight part.

  In still another vehicle of the present invention, the vehicle control device further sets an upper limit value and a lower limit value of the target value of the vehicle acceleration lower than when the road surface gradient is zero when the road surface gradient is positive. When the road surface gradient is negative, the upper limit value and the lower limit value of the target value of the vehicle acceleration are set higher than when the road surface gradient is zero.

  According to the configuration of the first aspect, since the target value of the vehicle acceleration is limited in accordance with the road surface gradient, the vehicle body does not come into contact with the road surface even on a slope, and the balance can be appropriately maintained. Therefore, it is possible to travel in a stable state regardless of the road surface gradient, and it is possible to always exhibit the true acceleration / deceleration limit performance according to an arbitrary road surface gradient.

  According to the structure of Claim 2, the limit value of the target value of vehicle acceleration can be set more appropriately according to the road surface gradient.

  According to the configuration of the third aspect, even when the active weight portion is moved and the vehicle body is tilted, the vehicle body does not contact the road surface and the balance can be maintained.

  According to the configuration of the fourth aspect, the limit value of the target value of the vehicle acceleration can be set more appropriately according to the road surface gradient.

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 figure for demonstrating the 2nd Embodiment of this invention, and is the schematic which shows the operation example in the slope of a vehicle. It is a graph which shows the change of the target value of vehicle acceleration in a 2nd embodiment of the present 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.

  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 operates the joystick 31 to input travel commands such as acceleration, deceleration, turning, in-situ rotation, stop, and braking of the vehicle 10. 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 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. Then, 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 control ECU 20 functions as a road surface gradient estimating unit that estimates a road surface gradient based on a change in the travel state of the vehicle 10 and the vehicle body posture over time. 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 operation example according to the prior art for comparison, and FIG. 3B shows an 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. As a result, in order to stop the vehicle 10 on a slope, that is, so that the vehicle 10 does not move in the downward direction, a driving torque is applied to the drive wheels 12 and the reaction torque, which is the reaction, acts on the vehicle body. The car body never tilts 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 diagram for explaining the second embodiment of the present invention, and is a schematic diagram showing an operation example on a slope of a vehicle. FIG. 12A shows an example of operation during stop for comparison, and FIG. 12B shows an example of operation during acceleration for comparison.

In the first embodiment, in order to move the center of gravity of the vehicle body so as to cancel the vehicle body tilting torque by the action of gravity, the riding unit 14 is first moved without tilting the vehicle body, When the active weight movement limit is reached, the vehicle body starts tilting. Therefore, when the vehicle is stopped on a slope, the vehicle body can be held upright as shown in FIG. However, if the acceleration is large when accelerating in the upward direction, it is necessary to incline the vehicle body toward the front in the traveling direction. Therefore, as shown in FIG. There is a possibility that the part contacts the road surface. On the slope, even if the vehicle body is standing upright, it is in a state of being inclined relative to the road surface, so there is little room to incline and even if the vehicle body is only slightly inclined from the upright state Contact the road surface. Note that the value of the vehicle body inclination angle θ ₁ in contact with the road surface varies depending on the road surface gradient η.

Further, if only the vehicle body inclination angle θ ₁ is limited with respect to the requested acceleration input by the occupant 15 by operating the joystick 31, the balance of the vehicle body with respect to the inertial force acting on the vehicle body and the drive motor anti-torque accompanying the vehicle acceleration. Cannot be maintained, and the vehicle body tilts greatly in the opposite direction. Therefore, on the slope, the occupant 15 needs to operate the joystick 31 with care so that the vehicle body does not contact the road surface.

  Of course, it is conceivable to set the upper limit value of the vehicle acceleration in advance so that the vehicle body does not touch the road surface on a slope, but in this case, it becomes impossible to realize a large vehicle acceleration on flat ground.

Therefore, in the present embodiment, the target acceleration of the vehicle 10 is limited according to the road surface gradient η, that is, the limit value of the vehicle acceleration target value α ^* is changed according to the value of the road surface gradient η. Thereby, even if it is a slope, a vehicle body does not contact a road surface, it can maintain a balance appropriately, and the stable driving | running | working state of the vehicle 10 is realizable irrespective of road surface gradient (eta).

  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.

  FIG. 13 is a graph showing changes in the target value of the vehicle acceleration in the second embodiment of the present invention, and FIG. 14 is a flowchart showing the operation of the target running state determination process in the second embodiment of the present invention. .

  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 limits or corrects the target value of the vehicle acceleration according to the value of the road surface gradient η acquired by the road surface gradient acquisition process (step S3-13). Here, the corrected vehicle acceleration target value α ^* is determined in consideration of the ground contact limit. More precisely, it is determined by the following equation (8).

Thus, the corrected vehicle acceleration target value α ^* changes as shown in FIG. 13 with respect to the vehicle acceleration target value determined based on the operation amount of the joystick 31. In FIG. 13, a solid line indicates a case where the road surface gradient η is positive, that is, a case where the road surface gradient η is uphill, and a dotted line indicates a case where the road surface gradient η is zero, that is, a case where the road surface is flat. In addition, when the road surface gradient η is negative, that is, when it is a downhill, it can be seen that it is above the dotted line.

Subsequently, the main control ECU 21 calculates the target value of the drive wheel rotational angular velocity from the corrected target value α ^* 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.

  Thus, in the present embodiment, the target value of the vehicle acceleration is limited according to the value of the road surface gradient η. At this time, two limit values (limit values), that is, a limit value corresponding to vehicle grounding and a limit value corresponding to the maximum value of the driving torque are taken into consideration, and the limit value is limited under more severe conditions. Here, the limit corresponding to vehicle body grounding is that when the riding section 14 is moved against the inertial force and the counter-torque accompanying the vehicle acceleration and the vehicle body is tilted to maintain balance, a part of the vehicle body contacts the road surface. If it is a vehicle acceleration and an acceleration higher than this is given, the posture control of the vehicle body cannot be maintained. Further, the limit corresponding to the maximum value of the driving torque is the vehicle acceleration when the driving torque is maximized on the slope of the road surface gradient η, and the acceleration of the driving motor 52 cannot be further increased. . By correcting the two kinds of limit values with the road surface gradient η, the true acceleration / deceleration limit performance according to the condition of an arbitrary road surface gradient η can always be exhibited.

  Further, when the magnitude relationship between the two types of limit values is invariant with respect to an arbitrary road surface gradient η, only one limit value may be considered. In general, the drive motor 52 can generate a sufficiently large torque, and the limit value corresponding to the maximum value of the drive torque is considered to be large. Therefore, only the limit value corresponding to the vehicle grounding should be considered. May be.

  The limit value corresponding to the vehicle ground contact is set according to the formula used when determining the target value of the active weight portion position and the target value of the vehicle body tilt angle in the determination process of the target vehicle body posture. Accordingly, the method for determining the vehicle body posture at the vehicle body contact limit can be corrected. For example, when there is a margin in the active weight portion movement amount at the vehicle body contact limit, instead of tilting the vehicle body, the riding portion 14 may be moved by a considerable amount.

  Further, in the present embodiment, it is assumed that the vehicle body inclination limit and the active weight part movement limit are the same in the front and the rear. Limit values can also be used.

  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.

  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.

  The present invention can be applied to a vehicle using posture control of an inverted pendulum.

DESCRIPTION OF SYMBOLS 10 Vehicle 12 Drive wheel 14 Boarding part 20 Control ECU

Claims (4)

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 limits the target value of the vehicle acceleration according to the road surface gradient, and the limit value of the target value of the vehicle acceleration corresponds to the limit value corresponding to the vehicle body grounding and the maximum value of the driving torque. The vehicle is set based on at least one of a limit value to be set.   The vehicle control device includes a value obtained by subtracting a value proportional to a road surface gradient from an absolute value of a limit value corresponding to vehicle body contact when the road surface gradient is zero, and a maximum driving torque when the road surface gradient is zero. 2. The vehicle according to claim 1, wherein a value obtained by subtracting a value proportional to a road surface gradient from an absolute value of a limit value corresponding to the value is a limit value corresponding to the vehicle body grounding and a limit value corresponding to a maximum value of driving torque. . Having an active weight portion movably attached to the vehicle body;
The vehicle control device sets a limit value corresponding to the vehicle body grounding based on at least one of a maximum value of an inclination angle due to rotation of the vehicle body and a maximum value of a moving amount of the active weight portion. The vehicle according to claim 1 or 2.   When the road gradient is positive, the vehicle control device sets an upper limit value and a lower limit value of the target value of the vehicle acceleration lower than when the road gradient is zero, and when the road gradient is negative, the vehicle acceleration The vehicle according to any one of claims 1 to 3, wherein an upper limit value and a lower limit value of the target value are set higher than when the road surface gradient is zero.

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