JP5067194B2 - 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 that has two drive wheels arranged on the same axis, detects a change in the posture of the vehicle body due to the movement of the center of gravity of the driver, and drives the vehicle body attached to a single spherical drive wheel. Techniques for vehicles that move while being controlled have been proposed (see, for example, Patent Document 1).

In this case, the vehicle is stopped or moved by controlling the operation of the rotating body while detecting the balance of the vehicle body and the state of the operation with the sensor.
JP 2007-219986 A

  However, in the conventional vehicle, when getting on and off the step, the folding operation may be performed halfway. Here, the folding operation is an operation that goes up and down to the middle of the step if going up the step, and an operation that goes up to the middle of the step if going down the step. When such a folding operation is performed, the vehicle may be unnecessarily accelerated or decelerated or the vehicle body may be greatly tilted. At this time, the passenger may feel uncomfortable or may be uneasy about the stability and safety of the vehicle. And this folding | turning operation | movement may be caused by the driver's improper operation that commands traveling in the reverse direction or sudden acceleration / deceleration while the vehicle is getting on and off the step.

  The present invention solves the problems of the conventional vehicle and fixes the target value of the vehicle acceleration in the middle of ascending / descending the step, so that the folding operation is not performed during the ascent / descent of the step. To provide a vehicle in which the driving state and the posture of the vehicle body are kept stable both when climbing up and down a step, and can be safely and comfortably driven even in a place with a step. Objective.

Therefore, in the vehicle of the present invention, based on a vehicle body, a drive wheel rotatably attached to the vehicle body, an input device for inputting a travel command, and the travel command input from the input device, the drive wheel And a vehicle control device that controls the posture of the vehicle body by controlling the driving torque applied to the vehicle, and the vehicle control device is a resistance caused by the step according to the posture of the vehicle body when the vehicle steps up and down the road surface. Step resistance torque estimating means for estimating the step resistance torque is provided, the drive torque is controlled according to the step resistance torque, and the target value of the vehicle acceleration is fixed during the elevation of the step regardless of the travel command.

  In still another vehicle of the present invention, the vehicle control device further includes a lift state determination unit that determines a lift state of the step based on the estimated value of the step resistance torque, and the lift state determination unit includes: When the estimated value of the step resistance torque is equal to or greater than a predetermined threshold value, it is determined that the step is being raised or lowered.

  In still another vehicle of the present invention, the vehicle control device fixes the target value of the vehicle acceleration to a value immediately before entering the step.

  In still another vehicle of the present invention, the vehicle control device fixes the target value of the vehicle acceleration when the lifting state determination means determines that the step has been started.

  In still another vehicle of the present invention, the vehicle control device is further determined according to the target value of the vehicle acceleration and the travel command after the lift state determining means determines that the lift of the step is finished. The difference between the vehicle acceleration target value and the target value is gradually reduced over time.

  In still another vehicle of the present invention, the vehicle control device further includes a time delay from the time when the lifting / lowering state determining means determines that the lifting / lowering of the step has been completed to release the fixation of the target value of the vehicle acceleration. Is provided.

  In still another vehicle of the present invention, the time delay is further determined in accordance with the rotational angular velocity of the drive wheel at the time when the lift state determination means determines that the step has been lifted.

According to the configuration of the first aspect , the folding operation is not performed in the middle of ascending / descending the step, and the traveling state and the posture of the vehicle body are stably maintained even when riding on the step or when getting off the step. You can drive safely and comfortably in a certain place.

According to the configuration of claim 2 , it is possible to prevent misrecognition of an estimated value of a minute step resistance torque due to disturbance or the like, and to accurately determine that the step is being raised or lowered.

According to the third and fourth aspects of the present invention, the target value of the vehicle acceleration can be fixed to an appropriate value from the start of raising / lowering of the step to the end of raising / lowering, and the vehicle running state and the vehicle body posture can be kept stable. .

According to the configuration of the fifth aspect , it is possible to prevent the target value of the vehicle acceleration from changing suddenly immediately after the end of the elevation of the step, and to keep the running state and the posture of the vehicle body stable.

According to the structure of Claim 6 and 7, the operation | movement which a vehicle heads for a level | step difference again by the driver | operator's improper operation immediately after completion | finish of raising / lowering of a level | step difference can be prevented.

  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 FIG. 1, reference numeral 10 denotes a vehicle according to the present embodiment, which includes a body portion 11, a drive wheel 12, a support portion 13, and a riding portion 14 on which an occupant 15 rides. Can be tilted. Then, the posture of the vehicle body is controlled similarly to the posture control of the inverted pendulum. 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 in the traveling direction.

  The drive wheel 12 is rotatably supported with respect to 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 axis of the drive wheel 12 exists in a direction perpendicular to the plane shown in FIG. 1, and the drive wheel 12 rotates around that axis. 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. The main body 11 has a riding section 14 that functions as an active weight section so that it can move relative to the main body 11 in the front-rear direction of the vehicle 10, in other words, relative to the tangential direction of the vehicle body rotation circle. It is attached so as to be movable.

  Here, the active weight part has a certain amount of mass, and actively corrects the position of the center of gravity of the vehicle 10 by moving it back and forth with respect to the main body part 11. The active weight portion does not necessarily need 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 movably attached to the main body portion 11, a weight, a weight (Weight), a device in which a dedicated weight member such as a balancer is movably attached to the main body 11 may be used. Moreover, you may use together the boarding part 14, a heavy peripheral device, an exclusive weight member, etc.

  Further, in the present embodiment, for convenience of explanation, an example in which the riding part 14 in a state in which the occupant 15 is boarded functions as an active weight part will be described, but the occupant 15 is not necessarily in the riding part 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. The vehicle is moved back and forth in the vehicle traveling direction. 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, other devices such as a pedal, a handle, a jog dial, a touch panel, and a push button can be obtained instead of the joystick 31 to obtain a target travel state. It can also be used as a device.

  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. 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.

  Further, the control ECU 20 functions as a step resistance torque estimating means for estimating the step resistance torque based on the travel state of the vehicle 10 and the time change of 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 step resistance torque. 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 step resistance torque. Specifically, it functions as step elevation torque determining means for determining the drive torque to be added according to the step resistance torque, and center of gravity correction amount determining means for determining the center of gravity correction amount of the vehicle body according to the step elevation torque.

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

  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 view showing the step-up / down operation of the vehicle in the first embodiment of the present invention, and FIG. 4 is a flowchart showing the operation of the vehicle travel and attitude control processing in the first embodiment of the present invention. . 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 case of a conventional vehicle as described in the “Background Art” section, as shown in FIG. 3A, the reaction of the drive torque applied to the drive wheels 12 to climb up the step, that is, the anti-torque is applied to the vehicle body. The vehicle body tilts backward. For this reason, it is not possible to perform stable vehicle body posture and travel control when riding on a step.

  In contrast, in the present embodiment, the riding section 14 functions as an active weight section, and as shown in FIG. 3B, the center of gravity of the vehicle 10 is set by moving the riding section 14 forward. Move forward. As a result, a gravitational torque is applied to tilt the vehicle body forward, so that the reaction when driving torque is applied to the drive wheel 12 for climbing the step, that is, even if the anti-torque acts on the vehicle body, Since the action is canceled out by the torque, the vehicle body does not tilt backward. Therefore, stable vehicle body posture and travel control can be performed even when riding on a step.

  Note that this embodiment is particularly effective when entering a step from a stopped state and a low-speed traveling state, that is, when the inertial force acting on the vehicle body as the vehicle decelerates due to contact with the step is small.

  Further, the driving torque for climbing up the step is estimated in real time during the climbing operation and applied to the drive wheels 12. As a result, stable riding is possible for any step shape and vehicle speed.

  In other words, in the present embodiment, the vehicle 10 can move up and down in a stable manner by executing the travel and posture control processing including the correction of the center of gravity of the vehicle 10 and the application of drive torque.

  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 step elevation torque determination process (step S2), and the state quantity acquired by the state quantity acquisition process, that is, the rotational state of the drive wheels 12, the tilt state of the vehicle body, and / or the riding section 14 is obtained. The step resistance torque is estimated by an observer on the basis of the movement state of each and the output value of each actuator, that is, the output value of the drive motor 52 and / or the active weight motor 62, and the step elevation torque is determined. 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 a target body posture determination process (step S4), and the step lift torque determined by the step lift torque determination process and the acceleration of the vehicle 10 determined by the target travel state determination process. Based on the target value, the target value of the vehicle body posture, that is, the 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), each state quantity acquired by the state quantity acquisition process, the step lift torque determined by the step lift torque determination process, and the target travel state The output of each actuator, that is, the output of the drive motor 52 and the active weight motor 62, is determined based on the target travel state determined by the determination processing of the target vehicle body and the target vehicle body posture determined by the determination processing of the target vehicle body posture. To do.

  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 (average of two drive wheels) [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 ]
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 : Viscosity damping coefficient [Ns / rad] for active weight part translation

  Next, the step elevation torque determination process will be described.

  FIG. 7 is a flowchart showing the operation of the step elevation torque determination process in the first embodiment of the present invention.

In the step elevation torque determination process, the main control ECU 21 first estimates the step resistance torque τ _D (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 (previous time step) travel and posture control process, The step resistance torque τ _D is estimated from (1).

Subsequently, the main control ECU 21 determines the step elevation torque τ _C (step S2-2). In this case, the estimated value of the step resistance torque τ _D is set as the value of the step lifting torque τ _C. That is, τ _C = τ _D.

  As described above, in the present embodiment, based on the driving torque output from the driving motor 52, the driving wheel rotation angular acceleration indicating the vehicle translational acceleration as the state quantity, the vehicle body inclination angular acceleration, and the active weight moving acceleration. Estimate the step resistance torque. 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 portion moving acceleration indicating the change in the vehicle body posture are considered. That is, the change in the vehicle body posture, which is a characteristic element of a vehicle using the posture control of the inverted pendulum, that is, the so-called inverted vehicle is taken into consideration.

  Conventionally, since the step resistance torque is estimated based on the drive torque and the driving wheel rotation angular acceleration, a large error may occur in the estimated value of the step resistance torque especially when the posture of the vehicle body is changing. . However, in the present embodiment, the step resistance torque is estimated in consideration of the vehicle body inclination angle acceleration indicating the change in the posture of the vehicle body and the active weight portion moving acceleration, so that a large error does not occur and the step is highly accurate. The resistance torque 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 step resistance torque 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 an influence. In a general inverted type vehicle, the weight ratio of the vehicle body with respect to the entire vehicle is high, and the change in posture during the step-up / down operation is large, so such an effect becomes large.

  In the present embodiment, the step resistance torque that changes during the step-up / down operation is always estimated. For example, if a constant drive torque is applied to the drive wheels 12 during the step-up / down operation, the vehicle 10 may be unnecessarily accelerated / decelerated immediately before the end of the lift. This is because, for example, when riding on a step, the step resistance torque decreases as the vehicle 10 climbs the step. Therefore, in this embodiment, the step resistance torque that changes with the step elevation state is estimated in real time, and the value is constantly updated so that the step elevation torque suitable for the step elevation operation is always applied. It has become.

  Note that the high frequency component of the estimated value can be removed by applying a low pass filter to the estimated value of the step resistance torque. 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, only the driving torque and the inertial force are considered, 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. are secondary. It may be considered as an 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 determination process of the target traveling state and the step lift torque τ _C acquired by the determination process of the step lift torque, the following expressions (2) and (3) are used: The target value of the active weight portion 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.

Thus, 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 acting on the vehicle body with the step lifting torque τ _C corresponding to the step resistance torque τ _D. 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 in consideration of the counter torque.

  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 climbs a step, the riding section 14 is moved forward, or the vehicle body is further tilted forward. Further, when the vehicle 10 goes down the step, the riding section 14 is moved rearward, or the vehicle body is further tilted rearward.

  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 level difference is not particularly high, the vehicle body is kept upright even on the level difference, so that it is easy to secure the field of view for the occupant 15. In addition, if the level difference is not particularly high, the vehicle body does not greatly tilt even on the level difference, so that a part of the vehicle body is prevented from contacting 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 limit.

  In this embodiment, when the acceleration is low or the level difference is low, only the movement of the riding section 14 is used, but some or all of the vehicle body tilt torque may be handled by the vehicle body tilt. Good. By tilting the vehicle body, the front-rear inertial force acting on the occupant 15 can be reduced.

  Furthermore, 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 by the following equation (4) from each target value and the step lifting torque τ _C, and the feedforward of the active weight motor 62 is determined by the following equation (5). Determine the output.

Thus, by automatically adding the step lifting torque τ _C according to the step resistance torque τ _D , that is, by correcting the driving torque according to the step resistance torque τ _D , when the step is raised or lowered Can also provide the same handling feeling as the flat ground. That is, it is possible to get on and off the level difference by the same steering operation as that on the flat ground. In addition, the vehicle 10 is not unnecessarily accelerated or decelerated when the level difference is raised or lowered with respect to 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 by the following equation (6) from the deviation between each target value and the actual state quantity, and the feedback output of the active weight unit motor 62 by the following equation (7). To decide.

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 step resistance torque τ _D is estimated by the observer, the step lifting torque τ _C is applied, and the riding section 14 is moved in the upper direction of the step. Therefore, the vehicle body can be held upright even on the level difference, and the level difference can be raised and lowered. In addition, an apparatus for measuring a step is not required, and the system configuration can be simplified and the cost can be reduced.

Furthermore, since in view of the vehicle body inclination angle theta ₁ and active weight portion position lambda _S indicates the attitude of the vehicle body is estimated the step lifting torque tau _C, without a large error occurs, the step lifting torque tau _C with extremely high precision Can be estimated.

  Note that this embodiment is effective not only when climbing a step, but also when descending a step. The acceleration of the vehicle when the step is lowered is suppressed by applying the step lifting torque, and the vehicle body is held upright by moving the riding portion 14 backward. The same applies to other embodiments described below.

  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 block diagram showing the configuration of the vehicle control system in the second embodiment of the present invention, and FIG. 13 is a schematic diagram showing the operation in raising and lowering the step of the vehicle in the second embodiment of the present invention. .

  In the first embodiment, the riding part 14 is attached so as to be able to translate relative to the main body part 11 in the front-rear direction of the vehicle 10 and functions as an active weight part. In this case, a moving mechanism including the active weight motor 62 is disposed, and thereby the riding section 14 is translated, so that the control system is complicated as the structure becomes complicated and the cost and weight increase. Further, the first embodiment cannot be applied to an inverted vehicle that does not have a moving mechanism for moving the riding section 14.

  Therefore, in the present embodiment, a moving mechanism for moving the riding section 14 is omitted. Also, as shown in FIG. 12, the active weight part control system 60 is omitted from the control system, and the active weight part control ECU 23, the active weight part sensor 61, and the active weight part motor 62 are omitted. Since the configuration of other points is the same as that of the first embodiment, description thereof is omitted.

  In the present embodiment, as shown in FIG. 13, when raising and lowering the step, the driving torque applied to the drive wheel 12 for raising and lowering the step, that is, the reaction to the step raising and lowering torque is applied to the vehicle body. By tilting the vehicle body in the upper direction of the step by an angle corresponding to the step lifting torque with respect to the vehicle body tilting torque acting as an anti-torque, the vehicle body tilting torque is canceled by the action of gravity to maintain a balance.

  In addition, as explained in the section of “Background Art”, for example, when a required driving torque is applied to the driving wheel when riding on a step, the reaction acts on the vehicle body, so that the vehicle body is in a direction opposite to the step, that is, It will be greatly inclined in the lower direction of the step. On the other hand, if the posture of the vehicle body is to be maintained upright, the necessary driving torque cannot be applied to the driving wheels, so that it is impossible to ride on the step. In addition, the same phenomenon occurs when getting down the step, and the vehicle body tilts forward.

  In contrast, in the present embodiment, the vehicle body is intentionally tilted in the upper direction of the step by an angle suitable for the height of the step, so that a stable body posture can be maintained even when the step is raised or lowered. It is possible to travel safely and comfortably in places with steps.

  Next, details of the traveling and posture control processing in the present embodiment will be described. The outline of the travel and attitude control process and the determination process of the target travel state are the same as those in the first embodiment, so the description is omitted, the state quantity acquisition process, the step elevation torque determination process, Only the target vehicle body attitude determination process and the actuator output determination process will be described. First, the state quantity acquisition process will be described.

FIG. 14 is a flowchart showing the operation of the state quantity acquisition process in the second embodiment of the present invention.

  Next, the step elevation torque determination process will be described.

  FIG. 15 is a flowchart showing the operation of the step elevation torque determination process in the second embodiment of the present invention.

In the step elevation torque determination process, the main control ECU 21 estimates the step resistance torque τ _D (step S2-11). 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 step resistance torque τ _D is estimated from equation (8).

Subsequently, the main control ECU 21 determines the step elevation torque τ _C (step S2-12). In this case, the estimated value of the step resistance torque τ _D is set as the value of the step lifting torque τ _C. That is, τ _C = τ _D.

  Thus, in the present embodiment, the step resistance torque is estimated based on the driving torque output from the driving motor 52, the driving wheel rotation angular acceleration and the vehicle body inclination angular 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 indicating the change in the vehicle body posture is considered. That is, the change in the vehicle body posture, which is a characteristic element of a vehicle using the posture control of the inverted pendulum, that is, the so-called inverted vehicle is taken into consideration.

  Conventionally, since the step resistance torque 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 step resistance torque especially when the posture of the vehicle body changes greatly. However, in the present embodiment, the step resistance torque is estimated in consideration of the vehicle body inclination angle acceleration indicating the change in the posture of the vehicle body, so that a large error does not occur and the step resistance torque can be estimated with high accuracy. it can.

  In the present embodiment, the step resistance torque that changes during the step-up / down operation is always estimated. For example, if a constant drive torque is applied to the drive wheels 12 during the step-up / down operation, the vehicle 10 may be unnecessarily accelerated / decelerated immediately before the end of the lift. This is because, for example, when riding on a step, the step resistance torque decreases as the vehicle 10 climbs the step. Therefore, in this embodiment, the step resistance torque that changes with the step elevation state is estimated in real time, and the value is constantly updated so that the step elevation torque suitable for the step elevation operation is always applied. It has become.

  As in the first embodiment, a high-frequency component of the estimated value can be removed by applying a low-pass filter to the estimated value of the step resistance torque. 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, only the inertial force is considered, but the rolling resistance of the drive wheel 12, the viscous resistance due to the friction of the rotating shaft, the air resistance acting on the vehicle 10, etc. are secondary effects. You may consider it.

  Further, a more accurate nonlinear model may be used, or a model for vehicle body tilt 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 vehicle body posture determination process will be described.

  FIG. 16 is a flowchart showing the operation of target body posture determination processing in the second embodiment of the present invention.

In the determination process of the target vehicle body posture, the main control ECU 21 first determines a target value of the vehicle body inclination angle (step S4-11). In this case, based on the target value of the vehicle acceleration determined by the target travel state determination process and the step lift torque τ _C acquired by the step lift torque determination process, the vehicle body inclination angle is expressed by the following equation (9). Determine the target value.

  Subsequently, the main control ECU 21 calculates the remaining target value (step S4-12). That is, the target values of the drive wheel rotation angle and the vehicle body inclination angular velocity are calculated by time differentiation or time integration of each target value.

Thus, 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 acting on the vehicle body with the step lifting torque τ _C corresponding to the step resistance torque τ _D. The target value of the vehicle body posture, that is, the target value of the vehicle body tilt angle is determined in consideration of the counter torque.

  At this time, the center of gravity of the vehicle body is moved so as to cancel the vehicle body tilt torque by the action of gravity. For example, when the vehicle 10 accelerates and climbs a step, the vehicle body is tilted forward. Further, when the vehicle 10 decelerates and descends a step, the vehicle body is tilted backward.

  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. 17 is a flowchart showing the operation of the actuator output determination process in the second embodiment of the present invention.

In the actuator output determination process, the main control ECU 21 first determines the feedforward output of the actuator (step S5-11). In this case, the feedforward output of the drive motor 52 is determined from the target value and the step elevation torque τ _{C according} to the equation (4) described in the first embodiment.

As shown in the above equation (4), by automatically adding a step lifting torque τ _C corresponding to the step resistance torque τ _D , the same control feeling as on the flat ground is provided even when the step is raised or lowered can do. That is, it is possible to get on and off the level difference by the same steering operation as that on the flat ground. In addition, the vehicle 10 is not unnecessarily accelerated or decelerated when the level difference is raised or lowered with respect to a certain steering operation of the joystick 31.

  In the present embodiment, more accurate control is realized by theoretically giving a feedforward output, but the feedforward output can be omitted if 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 the actuator (step S5-12). In this case, the feedback output of the drive motor 52 is determined by the following equation (10) from the deviation between each target value and the actual state quantity.

Note that nonlinear feedback control such as sliding mode control can also be introduced. As a simpler control, some of the feedback gains excluding K _W2 and K _W3 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 the element control system (step S5-13). 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 as a drive torque command value.

  As described above, in the present embodiment, the vehicle body can be tilted in the upper direction of the step to maintain the balance when the step is raised or lowered. Therefore, it can be applied to an inverted vehicle that does not have a moving mechanism for moving the riding section 14, and the structure and the control system are simplified, so that stable and low-level ingress and egress can be achieved even on an inexpensive and lightweight inverted vehicle. Can be realized.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st and 2nd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Also, the description of the same operations and effects as those of the first and second embodiments is omitted.

  FIG. 18 is a schematic diagram showing the configuration of the vehicle according to the third embodiment of the present invention, showing a state where a step is detected before the step, and FIG. 19 is a vehicle according to the third embodiment of the present invention. FIG. 20 is a block diagram showing a configuration of a vehicle control system according to a third embodiment of the present invention. 18, (b) is an enlarged view of the main part of (a), and (a) to (c) in FIG. 19 show a series of operations.

  If a constant driving torque is applied to the drive wheels 12 during the step-up / down operation, the vehicle 10 may unnecessarily accelerate / decelerate immediately before the end of the step-up / down operation. This is because, for example, when riding on a step, the step resistance torque decreases as the vehicle 10 climbs the step.

  Therefore, in the present embodiment, a step in the traveling direction of the vehicle 10 is detected by a sensor, and the position and height of the step measured by the sensor and the rotation angle of the driving wheel corresponding to the raised / lowered state of the step are determined. The step lifting torque is changed.

  Therefore, in the present embodiment, the vehicle 10 includes a distance sensor 71 as a step measurement sensor, as shown in FIG. The distance sensor 71 uses, for example, laser light, but may be any type of sensor. In the example shown in FIG. 18, two distance sensors 71 are disposed on the lower surface of the riding section 14 so as to be separated from each other in the front-rear direction, and each measures the distance from the lower surface to the front and rear road surfaces. And the level | step difference of a road surface can be detected from the change of the measured value of each distance sensor 71, and the position and height of the detected level | step difference can be acquired. Desirably, one distance sensor 71 is disposed in front of a portion of the driving wheel 12 that contacts the road surface, and the other distance sensor 71 is disposed rearward of a portion of the driving wheel 12 that contacts the road surface. Is done. Thus, since the two distance sensors 71 measure the distance to the road surface at a position away from the contact point of the drive wheel 12, the step difference between the front and rear of the vehicle 10 can be detected.

  Moreover, the vehicle 10 has a level difference measurement system 70 including a distance sensor 71 as shown in FIG. Then, the distance sensor 71 detects the ground distance as the distance to the road surface at two points on the front and rear sides, and transmits it to the main control ECU 21.

  Thus, for example, when riding on a step, as shown in FIG. 19, the amount of movement of the riding section 14, the driving torque for riding on the step, etc. are changed as the vehicle 10 rises, thereby stabilizing the vehicle body posture. And travel control can be performed.

  Next, details of the traveling and posture control processing in the present embodiment will be described. The outline of the travel and attitude control process, the state quantity acquisition process, the target travel state determination process, the target vehicle body attitude determination process, and the actuator output determination process are the same as those in the first embodiment. The description will be omitted, and only the process for determining the step lifting torque will be described.

  FIG. 21 is a diagram showing a geometric condition when measuring an ascending step according to the third embodiment of the present invention, and FIG. 22 is a step ascending / descending resistivity of the ascending step according to the third embodiment of the present invention. FIG. 23 is a diagram showing a geometric condition when measuring a down step in the third embodiment of the present invention, and FIG. 24 is a down view in the third embodiment of the present invention. The figure which shows the change of the level | step difference raising / lowering resistivity of a level | step difference, FIG. 25: is a flowchart which shows the operation | movement of the determination process of the level | step difference raising / lowering torque in the 3rd Embodiment of this invention.

  In the step elevation torque determination process, the main control ECU 21 first acquires the measurement value of the distance sensor 71 (step S2-21). In this case, the measured value of the ground distance is acquired from the two front and rear distance sensors 71.

Subsequently, the main control ECU 21 determines the position and height of the step (step S2-22). In this case, determined by the time history of the ground distance obtained from the distance sensors 71, the vehicle body inclination angle theta _1, the position of the riding section 14, i.e., based on the active weight portion position lambda _S, the position and height of the step To do.

Subsequently, the main control ECU 21 determines the step resistance torque τ _D (step S2-23). In this case, the step resistance torque τ _D is calculated by the following equation (11).
τ _D = ξτ _{D, Max} (11)
Here, τ _{D, Max} is the maximum step resistance torque, and ξ is the step elevation resistance.

As shown in FIG. 21, when the step is ascending, that is, ascending, the maximum step resistance torque τ _{D, Max} and the step elevation resistivity ξ are expressed by the following equations (12) and (13). In FIG. 21, X is the distance to the step when the step is detected, and H is the height of the step. In the case of ascending stage, H is zero or more.

In addition, η ₀ is a virtual climbing angle and corresponds to a driving wheel rotation angle necessary for climbing a step. Θ _{W, S} is the driving wheel rotation angle when the driving wheel 12 contacts the step, and θ _{W, 0} is the driving wheel rotation angle when the step is detected. Further, Δθ _W is the driving wheel rotation angle after the step contact, and the value becomes zero when the driving wheel 12 contacts the step.

Then, the value of the step resistance torque τ _D changes as shown in FIG. That is, the maximum value τ _{D, Max} is reached when the drive wheel 12 contacts the step, gradually decreases during the ascending step, and reaches the minimum value of zero when the ascending step is finished.

As shown in FIG. 23, when the step is down, that is, when the step is down, the maximum step resistance torque τ _{D, Max} and the step up / down resistivity ξ are expressed by the following equations (14) and (15). Is done. In FIG. 23, X is the distance to the step when the step is detected, and H is the height of the step. In the case of descending, H is less than zero, that is, minus.

Then, the value of the step resistance torque τ _D changes as shown in FIG. That is, the minimum value is zero when the drive wheel 12 contacts the step, gradually decreases during the descending step, and reaches the maximum value τ _{D, Max} immediately before the end of the descending step.

Finally, the main control ECU 21 determines the step elevation torque τ _C (step S2-24). In this case, the estimated value of the step resistance torque τ _D is set as the value of the step lifting torque τ _C. That is, τ _C = τ _D.

In this way, in the step elevation torque determination process, the step resistance torque τ _D is changed in accordance with the step height H. That is, the value of the step resistance torque τ _D is increased as the value of the step height H is increased.

Further, the magnitude of the step resistance torque τ _D is changed in accordance with the step elevation state of the vehicle 10. That is, the elevation state of the vehicle 10 is estimated from the drive wheel rotation angle θ _W and the value of the step elevation resistivity ξ is changed. Thereby, it is possible to cope with a speed change of the vehicle 10.

Specifically, when climbing a step, that is, when the step height H is zero or more, the step resistance torque τ _D (step elevation resistivity ξ) is decreased as the drive wheel rotation angle θ _W increases. This is because the driving torque required to support the vehicle 10 decreases as the level difference is increased.

On the other hand, when descending the step, that is, when the height H of the step is less than zero, the step resistance torque τ _D (step elevation resistivity ξ) is increased as the drive wheel rotation angle θ _W increases. This is because the driving torque required to support the vehicle 10 increases as the level difference is lowered.

  Thereby, the driving | running | working state of the vehicle 10 at the time of level | step difference raising / lowering can be controlled stably.

  In the present embodiment, only the case where the vehicle 10 moves forward and enters the step located in front of the vehicle 10 has been described. However, the same applies to the case where the vehicle 10 moves backward and enters the step located behind the vehicle 10. Control can be implemented.

  In the present embodiment, the case where the distance sensor 71 is not used during the step-up / down operation is described. However, in order to grasp the step-up / down state of the vehicle 10 more accurately, the measurement value of the distance sensor 71 is used. You can also Thereby, stable control can be performed even if the drive wheel 12 slips.

  Further, in the present embodiment, the case where a discontinuous function is used in the determination formula of the step elevation resistivity ξ has been described, but a function in which the discontinuous portion is continuously corrected can also be used. In addition, in order to prevent control chattering or vehicle operation hunting at discontinuous portions, hysteresis control (for example, control in which two threshold values are set and the threshold value is changed according to the rotation direction of the drive wheels 12) is introduced. Also good.

  Furthermore, in the present embodiment, the case of using a determinant based on a non-linear dynamic model has been described. However, for the sake of simplicity, a linear approximation formula may be used. Further, a more advanced determination formula that considers deformation of the drive wheel 12, rolling friction, slip conditions, and the like may be used.

As described above, in the present embodiment, the step in the traveling direction of the vehicle 10 is detected by the distance sensor 71, and according to the position and height H of the step measured by the distance sensor 71 and the driving wheel rotation angle θ _W. The value of the step elevation torque τ _C is changed. Therefore, the inverted posture of the vehicle body can be kept stable even when the step is raised or lowered. Thereby, the vehicle 10 can drive | work safely and comfortably also in the place with a level | step difference.

  In the present embodiment, the case where a step is detected and the position and height H of the step are measured by the two distance sensors 71 has been described. However, other devices and methods can be used. For example, the detection of the step and the position and height H of the step may be measured by acquiring an image of the traveling direction of the vehicle 10 with a camera and analyzing the acquired image. Further, for example, based on a vehicle position acquisition system that acquires the position of the vehicle 10 using GPS (Global Positioning System), and map data that includes information on the road surface and the level difference, the level difference that exists around the vehicle 10 is determined. Information may be acquired.

  Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as the 1st-3rd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those of the first to third embodiments is also omitted.

  FIG. 26 is a diagram showing a change in the step elevation degree in the fourth embodiment of the present invention, and FIG. 27 is a diagram showing a change in the step elevation torque addition amount in the fourth embodiment of the present invention. Shows an example of time change when climbing a step. FIG. 28 is a diagram showing a change in the torque addition rate in the fourth embodiment of the present invention, and FIG. 29 is a flowchart showing the operation of the step elevation torque determining process in the fourth embodiment of the present invention. .

When the vehicle 10 goes up or down a step, the vehicle may go down without going up the step or go up without going down the step. Such a turn-back operation of the vehicle 10 may be performed by an inappropriate operation in which the occupant 15 instructs to travel in the reverse direction or sudden acceleration / deceleration with the joystick 31 while the step is raised or lowered, or the step resistance torque τ. _This occurs because the difference between the estimated value of _D and the actual value is large, or the driving torque necessary for the attitude control of the vehicle body greatly affects the running state. And with this turning-back operation | movement, the vehicle 10 may accelerate / decelerate unnecessarily or the vehicle body may be greatly inclined.

Therefore, in the present embodiment, control is performed to prevent the folding operation during the elevation of the step. Specifically, the control ECU 20 as the vehicle control device includes a step resistance torque estimating unit that estimates the step resistance torque, and an up / down state determining unit that determines an up / down state of the step based on the estimated value of the step resistance torque. . When the estimated value of the step resistance torque τ _D deviates from a range defined by two predetermined threshold values, the lift state determination means determines that the step is being lifted. Then, in the middle of raising and lowering the step, the step raising and lowering τ _C is added when the driving wheel rotation angular velocity is lower than a predetermined ratio as compared with the step entering. In the middle of raising or lowering the step, the occupant 15 ignores changes in the operation amount of the joystick 31 for inputting a travel command such as acceleration, deceleration, turning, in-situ rotation, stop, braking, etc. of the vehicle 10, and the vehicle acceleration target The value is fixed to the value immediately before entering the step.

  Thereby, the folding operation | movement in the middle of raising / lowering of a level | step difference can be prevented, and the raising / lowering of a level | step difference can be performed reliably. In addition, the traveling state of the vehicle 10 and the posture of the vehicle body can be kept stable even while the step is raised and lowered, and the vehicle can travel safely and comfortably in a place with a step.

In the present embodiment, in the middle of step elevation, (a) control for adding step elevation torque τ _C when the driving wheel rotation angular velocity is smaller than that when entering the step, and (b) amount of operation of the joystick 31. Will be described, and both of the control for fixing the target value of the vehicle acceleration to the value immediately before entering the step will be described. However, only one of the control (a) and the control (b) is executed. You can also

  Next, details of the traveling and posture control processing in the present embodiment will be described. Note that the outline of the travel and attitude control process, the state quantity acquisition process, the target vehicle body attitude determination process, and the actuator output determination process are the same as those in the first embodiment, and a description thereof will be omitted. Only the step elevation torque determination process and the target travel state determination process will be described.

  First, the step elevation torque determination process will be described.

In the step elevation torque determination process, the main control ECU 21 first estimates the step resistance torque τ _D (step S2-31). In this case, as in the first embodiment, each state quantity acquired in the state quantity acquisition process and the actuator output determination process in the previous (previous time step) travel and posture control process are determined. Based on the output of each actuator, the step resistance torque τ _D is estimated by the equation (1).

Subsequently, the main control ECU 21 determines the step elevation degree β (step S2-32). In this case, the step elevation degree β is determined by the following equations (16) and (17) based on the time history of the step resistance torque τ _D. The step elevation β is an index indicating whether or not the vehicle 10 is moving up and down, β = 0 indicates that the step is not raised and β = 1 indicates that the step is raised and lowered. . Here, for convenience of explanation, only the case where the step is raised will be described, and the explanation about the case where the step is lowered is omitted, but the control processing when the step is lowered is the same as the control processing when the step is raised. .

For example, when the vehicle 10 climbs a certain step and the estimated value τ _D of the step resistance torque changes as shown in FIG. 26 (a), the value of the step elevation β is as shown in FIG. 26 (b). Change. 26A and 26B correspond to each other, and the same position on both axes represents the same time.

First, as a step lift start condition, step lifting of beta is beta = 0, and, when the estimated value tau _D of the step resistance torque satisfies τ _D ≧ τ _{D0, Max} or τ _D ≦ τ _{D0, Min,} It is determined that step elevation has started. Here, τ _{D0, Max} and τ _{D0, Min} are threshold values that define an upper limit and a lower limit of the step resistance torque estimation value that is determined not to be in the step elevation state.

When the time of a step lift start conditions have been satisfied and t _S, the stepped elevation of β is expressed by the following equation (16).

Also, as the step elevation end condition, when the step elevation degree β is β> 0 and the step resistance torque estimated value τ _D satisfies τ _{D0, Min} <τ _D < _{D0, Max} , the step elevation is finished. It is determined that Then, assuming that the time when the step elevation end condition is satisfied is t _E , the step elevation degree β is expressed by the following equation (17).

As described above, the main control ECU 21 determines whether or not the vehicle 10 is in the step up / down state based on the estimated value τ _D of the step resistance torque. Specifically, the step resistance torque τ _D is compared with two threshold values τ _{D0, Max} and τ _{D0, Min} to determine the step elevation state.

First, in a state in which the vehicle 10 is not moving up and down the level difference, that is, in a non-level difference level (β = 0), the estimated value τ _D of the step resistance torque is τ _D ≧ τ _{D0, Max} or τ _D ≦ τ _{D0, Min} If it is, it is determined that the step elevation has started, and the value of the step elevation degree β is changed from 0 to 1. In the state where the vehicle 10 is moving up and down the step, that is, in the step up and down state (β = 1), if τ _{D0, Min} <τ _D < _{D0, Max} , The value of the elevation degree β is changed from 1 to 0. In this way, by providing a width to the estimated value τ _D of the step resistance torque that is determined as a non-stepped lift state by the two threshold values τ _{D0, Max} and τ _{D0, Min} , a small step resistance torque caused by a disturbance or the like can be obtained. Misrecognition of the estimated value τ _D can be prevented.

Further, a transition state (0 <β <1) is provided between the non-step elevation state (β = 0) and the step elevation state (β = 1), and the transition between the two states is executed smoothly. That is, the step elevation degree β is linearly changed with a predetermined state transition time Δt _tr . As in the case of the control for preventing the folding operation performed in the present embodiment, when the control switching adapted to the transition between the two states is executed based on the step elevation β, this makes the control switching smooth and the traveling Sudden changes in state and vehicle posture can be prevented.

Further, a step up / down end time delay Δt _del is given to the determination of the step up / down end to intentionally delay the start of the transition from the step up / down state to the non-step up / down state. That is, the step elevation value β is not decreased until the step elevation end time delay Δt _del (= predetermined time) elapses after the step elevation end condition is satisfied (= the target value is not fixed). ). The step elevation end time delay Δt _del is a time required to travel a predetermined step separation distance ΔX _E at the traveling speed of the vehicle 10 at the end of the step elevation. That is, Δt _del is determined according to the traveling speed of the vehicle. The lower the traveling speed of the vehicle 10, the longer the step elevation end time delay Δt _del becomes. By continuing the control of preventing the folding operation until the vehicle 10 is separated from the step to some extent, it is prevented that the vehicle 10 heads for the step again immediately after the step up / down end determination, that is, the vehicle does not go down the same step immediately after reaching the step up / down. be able to.

  Further, after the determination of the step elevation has been completed, the determination of the step elevation restart is not performed until a certain time has elapsed. That is, when the step elevation β is β> 0, the next step elevation restart is not determined unless the step elevation β returns to β = 0. Thereby, it is possible to prevent the control for preventing the folding operation from being intermittently executed in a short cycle.

  On the other hand, when the step elevation degree β is β <1, it is always determined whether or not the step is finished. As a result, the step elevation degree β increased by erroneous determination can be quickly returned to β = 0, and unnecessary prevention of the folding operation prevention can be prevented.

In the present embodiment, the example in which the step separation distance ΔX _E is indirectly considered by the step elevation end time delay Δt _del based on the driving wheel rotation angular velocity at the end of the step elevation has been described. However, the step separation distance ΔX _E Can also be considered more directly. For example, the step elevation degree β may not be decreased until a predetermined drive wheel rotation angle increase amount is measured after the step elevation. Thereby, even if it is a case where the running speed of the vehicle 10 is low when it is determined that the step elevation is finished, the transition to the non-step elevation state can be appropriately set.

  In the present embodiment, the transition between the non-step elevation state and the step elevation state is realized using a linear function for the step elevation degree β, but a nonlinear function is used instead of the linear function. A smoother transition may be realized by using a function.

Furthermore, in this embodiment, predetermined values are given in advance to the two threshold values τ _{D0, Max} and τ _{D0, Min} used for the determination of the stepped state, but these values may be appropriately corrected. For example, the two threshold values may be automatically corrected based on a statistical characteristic amount in the time history of the estimated value of the step resistance torque τ _D.

Finally, the main control ECU 21 determines the step elevation torque τ _C (step S2-33). In this case, the step elevation torque τ _C is determined by the following equation (18) based on the step resistance torque τ _D.
τ _C = τ _D + Δτ _C (18)
Here, Δτ _C is an additional amount of step lifting torque, and is determined based on the step lifting degree β and the driving wheel rotation angular velocity.

For example, when the vehicle 10 climbs a certain step and the estimated value τ _D of the step resistance torque and the value of the step elevation β change as shown in FIGS. The step height increasing torque Δτ _C with respect to is set as shown in FIG. Note that the time axes that are the horizontal axes in FIG. 27 correspond to each other, and the same position on each horizontal axis represents the same time. FIGS. 27A and 27B are the same as FIGS. 26A and 26B.

Specifically, the step elevation torque additional amount Δτ _C is determined by the following equation (19).

In this way, the main control ECU 21 determines the step lifting torque τ _C by adding the driving torque that prevents the folding operation during the step lifting to the step resistance torque τ _D.

That is, when the traveling speed of the vehicle 10 is significantly lower than the traveling speed of the vehicle 10 at the start of the step elevation, the step elevation torque additional amount Δτ _C is added in the direction to assist the step elevation. Specifically, when the drive wheel rotation angular velocity during step elevation is compared with the drive wheel rotation angular velocity at the start of step elevation, if the ratio ν of both falls below the torque addition start rate rate ν _lim , which is a predetermined threshold, Add the step lift torque additional amount Δτ _C proportional to the difference.

In FIG. 27 (c), when the driving wheel rotation angular velocity during the step elevation indicated by the dotted line is less than the value obtained by multiplying the driving wheel rotation angular velocity at the start of the step elevation by the torque addition start velocity ratio ν _lim , This indicates that a step elevation torque addition amount Δτ _C indicated by a solid line is added.

In addition, the step elevation torque additional amount Δτ _C is limited by the maximum torque additional amount Δτ _{C, Max} which is a predetermined upper limit value. As a result, adverse effects on vehicle body posture control due to excessive addition of drive torque are suppressed.

In this way, the decrease in the traveling speed of the vehicle 10 is appropriately determined, and the step lift torque additional amount Δτ _C corresponding to the decrease is added to the step resistance torque τ _D to determine the step lift torque τ _C.

Further, the step lifting torque addition amount Δτ _C is determined according to the step lifting degree β. Specifically, after the determination of the start of step elevation, the reference value of the step elevation torque addition amount Δτ _C (step difference elevation torque addition amount Δτ _{C when} ν <ν ₁ ) is linearly increased along with the step elevation degree β. As a result, it is possible to prevent a step change raising / lowering torque τ _C accompanying a transition between the non-step raising / lowering state and the step raising / lowering state, and a sudden change in the running state or the vehicle body posture.

Further, after the determination of the end of step elevation, the reference value of the step elevation torque addition amount Δτ _C is made constant along with the step elevation degree β until a predetermined time, that is, until the step elevation end time delay Δt _del elapses, Decrease linearly. Thus, the vehicle 10 can be reliably detached from the step by continuing the addition of the step lifting torque addition amount Δτ _C to some extent.

In the present embodiment, the step resistance torque tau _D maximum torque additional amount .DELTA..tau _C independently of a predetermined value from the estimated value _of, although the _Max, said maximum torque additional amount .DELTA..tau _C, the _Max The value can be changed according to the estimated value of the step resistance torque τ _D. For example, when the estimated value of the step resistance torque τ _D is larger than a predetermined threshold value, a value obtained by multiplying the estimated value by a predetermined coefficient is set as the maximum torque addition amount Δτ _{C, Max} , so The additional torque amount Δτ _C can be added.

Further, in the present embodiment, the vehicle 10 is surely separated from the vicinity of the step by the step lift end time delay Δt _del , but a predetermined drive wheel rotation angle increase amount is measured after the step lift is finished. The addition of the step lifting torque addition amount Δτ _C may not be terminated until the above. As a result, even when the traveling speed of the vehicle 10 is extremely low when it is determined that the step elevation is finished, the vehicle 10 can be reliably detached from the step.

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

  FIG. 30 is a diagram showing a change in the target vehicle acceleration according to the fourth embodiment of the present invention, and shows an example of a time change when climbing a step. FIG. 31 is a flowchart showing the operation of target travel state determination processing in the fourth embodiment of the present invention.

  In the target travel state determination process, the main control ECU 21 first acquires a steering operation amount (step S3-31). 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 obtained operation amount of the joystick 31 and the step elevation degree β (step S3-32). In this case, the vehicle acceleration target value α ^* is determined by the following equation (21).

For example, when the vehicle 10 climbs a certain step and the estimated value τ _D of the step resistance torque and the value of the corrected step elevation change as shown in FIGS. 30A and 30B, the operation amount of the joystick 31 is increased. target value of the vehicle acceleration with respect to the target value alpha _d ^* of the change in vehicle acceleration based on alpha ^* is set as shown in FIG. 31 (c). Note that time axes that are horizontal axes in FIG. 31 correspond to each other, and the same position on each horizontal axis represents the same time. Moreover, Fig.31 (a) is the same figure as Fig.26 (a).

Thus, the main control ECU 21 ignores the operation of the joystick 31 by the occupant 15 during the step elevation operation, and fixes the target value of the vehicle acceleration to the value immediately before the step entry. In FIG.30 (c), the dotted line has shown the target value of the vehicle acceleration according to the operation amount of the joystick 31 in the level | step difference raising / lowering operation | movement.

Then, after determining whether or not the step is finished, the vehicle acceleration target value is gradually brought closer to the vehicle acceleration target value determined according to the operation amount of the joystick 31. In this case, it is determined that the step elevation has ended based on the estimated value of the step resistance torque τ _D , and the step elevation degree β decreases after a predetermined time, that is, the step elevation end time delay Δt _del has elapsed. Accordingly, the target value of the vehicle acceleration is brought closer to the target value of the vehicle acceleration corresponding to the operation amount of the joystick 31 from the target value of the vehicle acceleration at the time of starting the step elevation with a predetermined state transition time Δt _tr . As a result, it is possible to prevent a sudden change in the running state and the vehicle body posture accompanying a sudden change in the target value of the vehicle acceleration, and the same due to an inappropriate operation of the joystick 31 of the occupant 15 immediately after the step up and down. It is possible to prevent re-entry into the step.

Finally, 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 S3-33). 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.

  In the present embodiment, an example in which the target value of the vehicle acceleration is fixed by ignoring any operation of the joystick 31 of the occupant 15 after the determination of the start of the step elevation is described. On the other hand, the target value of the vehicle acceleration may be released and the target value of the vehicle acceleration may be determined according to the amount of operation of the joystick 31. For example, when the target value of the vehicle acceleration corresponding to the operation amount of the joystick 31 is smaller than a predetermined negative threshold, it is determined that the occupant 15 is requesting to interrupt the step elevation, and the target value of the vehicle acceleration is fixed. And the target value of the vehicle acceleration may be determined according to the amount of operation of the joystick 31. Thereby, for example, it is possible to sense a special danger avoidance operation of the occupant 15 in an emergency and to realize an appropriate traveling state.

  Further, in the present embodiment, the example in which the target value of the vehicle acceleration is fixed irrespective of the vehicle speed (drive wheel rotation angular speed) and the target value has been described. However, the vehicle speed, the target value, and the operation amount of the joystick 31 are described. Accordingly, the fixed vehicle acceleration target value may be released. For example, when the joystick 31 is operated to increase the vehicle acceleration target value while raising or lowering the step when the driving wheel rotation angular velocity or the target value is lower than a predetermined threshold value, the joystick 31 is operated according to the operation amount. The value may be determined as a target value for vehicle acceleration. Thereby, the step elevation operation can be completed more reliably.

  Furthermore, in the present embodiment, an example has been described in which the target value of the vehicle acceleration at the start of step elevation is fixed to any value, but it may be fixed to a value different from that value. For example, when the vehicle speed (drive wheel rotation angular velocity) or its target value is lower than a predetermined threshold value, a predetermined negative value or zero is set as a lower limit value for the vehicle acceleration target value at the start of step elevation, and the subsequent vehicle You may restrict | limit the fixed value of the target value of acceleration. Further, for example, when the vehicle speed target value falls below a predetermined positive threshold due to the fixed negative vehicle acceleration target value during the step up / down operation, the vehicle acceleration target value is set to zero and the vehicle speed target value is set to zero. The value may be fixed to the threshold value. Thereby, it can avoid that the vehicle speed falls extremely and can prevent the folding operation | movement in the middle of raising / lowering a level | step difference more reliably.

Further, in the present embodiment, the step elevation state is determined based on the estimated value of the step resistance torque τ _D , the control for adding the step elevation torque τ _C, and the control for fixing the target value of the vehicle acceleration to the value immediately before the step entry. As described in the third embodiment, a step measurement sensor such as the distance sensor 71 is used, and the step lifting torque τ _C is calculated based on the measurement result of the step measurement sensor. You may perform control which fixes the target value of control to add and vehicle acceleration to the value immediately before level | step difference approach.

  Furthermore, in the present embodiment, only the case where the vehicle has advanced and entered the step located in front of the vehicle 10 has been described, but the same applies to the case where the vehicle 10 moves backward and enters the step located behind the vehicle 10. Control can be implemented.

  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 level | step difference raising / lowering operation | movement of the vehicle 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 the operation | movement of the determination process of the level | step difference raising / lowering torque 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 block diagram which shows the structure of the control system of the vehicle in the 2nd Embodiment of this invention. It is the schematic which shows the operation | movement in the raising / lowering of the level | step difference of the vehicle in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the acquisition process of the state quantity in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the level | step difference raising / lowering torque in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the target vehicle body attitude | position in the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the actuator output in the 2nd Embodiment of this invention. It is the schematic which shows the structure of the vehicle in the 3rd Embodiment of this invention, and is a figure which shows the state which has detected the level | step difference before the level | step difference. It is the schematic which shows the operation | movement in the raising / lowering of the level | step difference of the vehicle in the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the control system of the vehicle in the 3rd Embodiment of this invention. It is a figure which shows the geometric conditions when measuring the level | step difference of the up in the 3rd Embodiment of this invention. It is a figure which shows the change of the level | step difference raising / lowering resistivity of the uphill level | step difference in the 3rd Embodiment of this invention. It is a figure which shows the geometric conditions when measuring the level | step difference of the down in the 3rd Embodiment of this invention. It is a figure which shows the change of level | step difference raising / lowering resistivity of the level | step difference of the downward in the 3rd Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the level | step difference raising / lowering torque in the 3rd Embodiment of this invention. It is a figure which shows the change of the step elevation degree in the 4th Embodiment of this invention. It is a figure which shows the change of the level | step difference raising / lowering torque additional amount in the 4th Embodiment of this invention. It is a figure which shows the change of the torque addition rate in the 4th Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the level | step difference raising / lowering torque in the 4th Embodiment of this invention. It is a figure which shows the change of the target vehicle acceleration in the 4th Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the target driving state in the 4th Embodiment of this invention.

Explanation of symbols

10 Vehicle 12 Drive wheel 20 Control ECU
30 Input device

Claims (7)

The car body,
A drive wheel rotatably mounted on the vehicle body;
An input device for inputting a travel command;
A vehicle control device for controlling the posture of the vehicle body by controlling a drive torque applied to the drive wheel based on a travel command input from the input device;
The vehicle control device includes step resistance torque estimating means for estimating a step resistance torque that is a resistance due to the step according to the posture of the vehicle body when raising or lowering a step on the road surface, and the driving torque according to the step resistance torque And a vehicle acceleration target value is fixed during the elevation of the step regardless of the travel command. The vehicle control device includes a lift state determination unit that determines a lift state of the step based on an estimated value of the step resistance torque,
Elevating state determining means, when the estimated value of the step resistance torque is equal to or greater than a predetermined threshold value, the vehicle according to claim 1, determines that the middle elevation of the step. The vehicle control device of the vehicle according to claim 1 or 2 fixes the target value of the vehicle acceleration value immediately before entry into the step. The vehicle according to claim 2 , wherein the vehicle control device fixes the target value of the vehicle acceleration when the lift state determination means determines that the lift of the step is started. The vehicle control device determines a difference between a target value of the vehicle acceleration and a target value of the vehicle acceleration determined in accordance with the travel command after determining that the lifting state determination means has finished raising and lowering the step. vehicle according to claim 2 or 4 to decrease with the passage. The vehicle control device of the vehicle according to claim 4 or 5 wherein the lifting state determining means releases the fixing of the target value of the vehicle acceleration from determining that it has finished the lifting of the step after a predetermined time. The vehicle according to claim 6 , wherein the predetermined time is determined according to a rotational angular velocity of the drive wheel when the lifting state determination unit determines that the lifting of the step has been completed.

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