JP2023064465A - Vehicular control apparatus - Google Patents

Abstract

To acquire a steering mid-point in a case where the steering mid-point is not stored.SOLUTION: A vehicle controlled by a control apparatus includes: an angle sensor for detecting a steering angle of a steering mechanism; and an electric actuator for applying steering torque to the steering mechanism. The control apparatus performs: learning a steering mid-point of the steering mechanism; performing a stationary-steering up to a left-right maximum steering angle at a control start of an automatic driving if the steering mid-point has not been learned when a request for starting automatic driving control of a vehicle is detected, with the vehicle stopped; and calculating the steering mid-point on the basis of an angle sensor value in the case of performing the stationary-steering up to the left maximum steering angle and an angle sensor value in the case of performing the stationary-steering up to the right maximum steering angle.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle control device.

2. Description of the Related Art Research and development have been conducted on control devices that can assist a driver's steering operation in driving a vehicle and control automatic driving of a vehicle by applying a steering torque from an electric actuator to a steering mechanism. In control of a steering mechanism using an electric actuator, sensors such as an angle sensor whose sensor value changes according to a change in steering angle and a sensor that detects the rotation angle of the motor of the electric actuator are generally used. These sensor values are compared to the steering angle midpoint and the difference angle between them is used as input for steering control. If the sensor is a relative angle sensor, learning of the steering angle midpoint is performed.

Patent Literature 1 describes an estimating device for estimating a steering angle midpoint. This estimating device sequentially performs Bayesian estimation on each of the parameters related to the state of the steering device and the parameters related to the driving state of the vehicle, and when the obtained probability satisfies a predetermined condition, the current steering angle is within the steering angle. A steering angle midpoint is estimated by determining that the point is a point.

JP 2021-017125 A

For example, the value of the steering angle midpoint may not be stored for some reason, such as when the battery is cleared. In such a case, steering control using the steering angle midpoint cannot be performed until the steering angle midpoint is newly learned. Therefore, in a state in which the steering angle midpoint is not stored, for example, a vehicle stopped in an unmanned state cannot be started by automatic driving. In this regard, in order to obtain the steering angle midpoint by the method described in Patent Document 1, the vehicle must be traveling on a straight road or the like under predetermined conditions. Therefore, in the steering angle midpoint acquisition method of Patent Document 1, a vehicle that has stopped in a state where the steering angle midpoint value is not stored cannot be automatically started.

For example, in vehicles for MaaS (Mobility as a service), it is easy to imagine a scene in which automatic driving starts from a parking position in an unmanned state, depending on the type of service. Therefore, in the case of a vehicle for MaaS, it is important to be able to start by automatic driving even in a state where the steering angle midpoint is not stored.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object thereof is to provide a technique that enables a vehicle that has stopped in a state in which the steering angle midpoint is not stored to start automatically. be.

A vehicle control device according to the present invention is applied to a vehicle that includes an angle sensor that detects a steering angle of a steering mechanism of the vehicle, and an electric actuator that applies steering torque to the steering mechanism. The control device includes means for learning the steering angle midpoint of the steering mechanism, and the steering angle midpoint learned when a request to start control of automatic driving of the vehicle is detected while the vehicle is stopped. If not, the means for stationary steering to the left and right maximum steering angle, the angle sensor value when stationary steering is performed to the left maximum steering angle, and the angle sensor value when stationary steering is performed to the right maximum steering angle and means for calculating a steering angle midpoint based on .

According to the vehicle control device of the present invention, even when the vehicle is stopped with no stored steering angle midpoint, the steering angle midpoint can be acquired before the vehicle starts, thereby enabling automatic driving. can start the vehicle.

FIG. 2 is a diagram for explaining an outline of a steering midpoint acquisition method according to Embodiment 1 of the present invention; FIG. 4 is a flowchart showing an example of a control procedure when obtaining a steering angle midpoint, which is executed by the control device according to Embodiment 1 of the present invention; 9 is a flowchart showing an example of a control procedure when obtaining a steering angle midpoint, which is executed by a control device according to Embodiment 2 of the present invention; FIG. 11 is a flow chart showing an example of a control procedure when obtaining a steering angle midpoint, which is executed by a control device according to Embodiment 3 of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, when referring to numbers such as the number, quantity, amount, range, etc. of each element in the embodiments shown below, unless otherwise specified or clearly specified by the number in principle, the reference The present invention is not limited to this number. Also, the structures, steps, etc. described in the embodiments shown below are not necessarily essential to the present invention, unless otherwise specified or clearly specified in principle.

Embodiment 1.
The control device according to the present embodiment has a function of controlling automatic driving of the vehicle and a function of assisting the driver in driving the vehicle. The control device is an ECU (Electronic Control Unit) having at least one memory and at least one processor. The memory stores various data including various programs and maps used for vehicle control including steering control. Various functions related to vehicle control are implemented by the processor reading and executing the program from the memory. Note that the control device may be configured by a plurality of ECUs.

In the present embodiment, in particular, the control device performs steering control for controlling the steering device of the vehicle during automatic driving of the vehicle. The steering system is, for example, an electric power steering system (EPS), and includes a steering handle for operation by the driver, and a steering mechanism that connects the steering handle and steered wheels. The steering system also includes an electric actuator configured to apply a steering torque to the steering mechanism. The electric actuator includes an electric motor and a speed reducer that transmits the torque of the electric motor to the steering mechanism.

For steering control, detection results of various sensors are input to the control device. Various sensors include, for example, a vehicle speed sensor, a torque sensor, a motor rotation angle sensor, a pinion angle sensor, and the like. The pinion angle sensor is an angle sensor that detects the steering angle, and detects the angle of the pinion shaft that rotates according to the steering of the steered wheels. The control device acquires the rotation angle of the electric motor based on the detected value of the motor rotation angle sensor. The rotation angle of the electric motor corresponds to the rotation angle of the steering wheel, and the steering angle of the steering wheel can be obtained from the sensor value of the motor rotation angle sensor.

The control device is configured to control the steering torque for steering control applied from the electric actuator to the steering mechanism by controlling the supply of motor current to the electric motor. In steering control, the difference between the sensor value of the motor rotation angle sensor and the steering angle midpoint is used as an input. In other words, the value of the steering angle midpoint is required to execute steering control. The steering angle midpoint can be calculated, for example, by sampling sensor values of a motor rotation angle sensor under predetermined operating conditions and statistically processing the values, and the calculated value is stored in the control device as a learning value.

However, while the vehicle is stopped, the steering angle midpoint may not be stored due to some factor such as battery clearance. In contrast, the control device according to the present embodiment performs control for acquiring the steering angle midpoint when the steering angle midpoint is not stored when the vehicle starts from a stopped state in automatic driving. Execute. As a result, even when the steering angle midpoint is not stored, it is possible to transmit the vehicle by automatic driving.

FIG. 1 is a diagram showing an outline of a method of acquiring a steering angle midpoint in this embodiment. In FIG. 1, the vertical axis represents the value of the pinion angle sensor, and the left rotation direction is indicated as plus and the right rotation direction as minus. Also, the horizontal axis indicates time. A method of acquiring the steering angle midpoint according to the present embodiment will be described below with reference to FIG.

When acquiring the steering angle midpoint, as shown in FIG. 1, stationary steering is first performed to the left maximum steering angle. That is, the target value is increased and stationary steering is performed to the left until the current value of the pinion angle sensor is saturated. Then, the saturated value is acquired as the left maximum value Lmax. After the current value of the pinion angle sensor is saturated, the steering direction is reversed, the target value is decreased until the current value is saturated, and stationary steering is performed to the right. Then, the saturated value is obtained as the right maximum value Rmax. The control device obtains an intermediate value between the left maximum value Lmax and the right maximum value Rmax thus acquired, and learns this intermediate value as the steering angle midpoint.

The determination of whether to stop increasing or decreasing the target value when obtaining the steering angle midpoint may be made by referring to the pinion angle deviation, the current value, etc., in addition to the current value of the pinion angle sensor. As a result, the load on the EPS due to stationary steering can be reduced.

FIG. 2 is a flowchart showing an example of a control procedure for obtaining a steering angle midpoint, which is executed by the control device according to the present embodiment. A control procedure for obtaining the steering angle midpoint will be described below with reference to FIG.

As shown in FIG. 2, in step S11, first, it is determined whether or not there is a request to start automatic operation control. Specifically, for example, when the automatic driving control is turned on by operating an automatic driving control ON/OFF switch mounted in the vehicle, it is determined that the automatic driving control is requested. Further, when the vehicle is operated remotely, it is determined that there is a request for automatic operation control when a signal requesting automatic operation control is received from a remote location.

If it is determined in step S11 that there is no request for automatic operation control, the current process ends. On the other hand, if it is determined in step S11 that there is a request for automatic operation control, then the process proceeds to step S12.

In step S12, it is determined whether or not the execution conditions for the automatic driving control are satisfied, excluding the presence or absence of storage of the steering angle midpoint. If the conditions for executing the automatic operation control are not satisfied, the current processing is terminated as it is. On the other hand, when it is determined in step S12 that the conditions for executing the automatic driving control are satisfied, the process proceeds to step S13.

In step S13, it is determined whether or not the steering angle midpoint has not yet been acquired. If the steering angle midpoint value is not stored in the control device, it is determined in step S13 that the steering angle midpoint value has not been acquired. The point is determined not to have been acquired. If it is determined in step S13 that the steering angle midpoint has not yet been obtained, the process proceeds to step S14, automatic driving control is turned ON, and automatic driving control is started. On the other hand, if it is determined in step S13 that the midpoint of the steering angle has not been obtained, then the process proceeds to step S15.

At step S15, it is determined whether or not the vehicle is currently stopped. Whether the vehicle is stopped can be determined by, for example, the wheel value pulse sensor value, the GPS speed observation result, or a combination of the wheel speed pulse sensor value and the GPS speed observation result. When making a determination based on the wheel speed pulse sensor value, for example, it is possible to determine that the vehicle is stopped on condition that the pulse value has not been updated for a predetermined time or longer.

If it is determined in step S15 that the vehicle is not stopped, the current control is terminated. On the other hand, if it is determined in step S15 that the vehicle is stopped, the process proceeds to step S16. In step S16, the automatic driving control is turned ON, and the automatic driving control is started.

The process then proceeds to step S17. In step S17, a steering torque is applied to the steering mechanism by steering control by automatic operation. Then, stationary steering is performed to the maximum left and right angles as described above, and the steering angle midpoint is calculated from the acquired left maximum value Lmax and right maximum value Rmax. After that, the processing of this time is terminated.

As described above, according to the present embodiment, even if the steering angle midpoint is not stored in the control device for some reason, the steering angle midpoint can be acquired while the vehicle is stopped, and automatic driving can be performed. can start the vehicle.

Embodiment 2.
The control device according to Embodiment 2 has the same configuration as that of the control device according to Embodiment 1, except that the steering angle midpoint is obtained by steering control while the vehicle is traveling slowly. Specifically, the procedure for acquiring the steering angle midpoint in the second embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing an example of a control procedure for obtaining a steering angle midpoint, which is executed by the control device according to the second embodiment.

The control shown in FIG. 3 is executed instead of the processing in FIG. The flow chart of FIG. 3 is the same as the flow chart of FIG. 2 except that steps S21 and S22 are performed instead of step S17.

Specifically, in the control procedure shown in FIG. 3, when it is determined in step S15 that the vehicle is currently stopped, the process proceeds to step S21, in which it is determined whether there are any obstacles around the vehicle. be done. Whether or not there is an obstacle around the vehicle is determined based on information acquired by a camera, sensor, or the like mounted on the vehicle.

Next, the process proceeds to step S16, and the automatic driving control is turned ON. Next, in step S22, the steering angle midpoint is obtained. When acquiring the steering angle midpoint in step S22, the control device causes the vehicle to run at the lowest speed at which the vehicle can be steered. In this state, the vehicle is steered to the maximum left and right steering angles in the same manner as in the first embodiment, the left maximum value Lmax and the right maximum value Rmax of the pinion angle sensor values are obtained, and the intermediate value thereof is obtained. The obtained intermediate value is set as the steering angle midpoint. After that, the processing of this time is terminated.

As described above, in the present embodiment, after the automatic operation control is turned on, the steering angle midpoint can be acquired by running the vehicle at the lowest vehicle speed that allows stationary steering and performing steering control. can. For example, even a vehicle that cannot be steered stationary due to insufficient axial force of the EPS can start traveling by automatic operation after acquiring the steering angle midpoint when the vehicle starts traveling by automatic operation.

In the second embodiment, a case has been described in which the vehicle is driven at the lowest speed at which the vehicle can be steered when the midpoint of the steering angle is acquired. However, the vehicle speed at which the steering angle midpoint is acquired is not limited to the minimum speed at which steering is possible, and may be set to another speed. However, even in this case, the speed shall be such that the vehicle can be stopped immediately. The load on the tires can be reduced by controlling the acquisition of the steering angle midpoint while the vehicle is traveling slowly.

Embodiment 3.
The control device according to the third embodiment performs a process of notifying the surroundings in advance when the steering angle midpoint acquisition control is executed in the first embodiment. FIG. 4 is a flow chart for explaining the control procedure executed by the control device according to the fourth embodiment. The control process in FIG. 4 is executed instead of the control in FIG. 2 or 3. FIG. The flowchart of FIG. 4 is the same as the flowchart of FIG. 2 except that the process of step S31 is provided between the process of step S16 and the process of step S17 of the flowchart of FIG.

In the present embodiment, as shown in FIG. 4, after the automatic operation control is turned ON in step S16, it is notified that stationary steering is to be performed in step S31. The notification method here is not limited, and for example, notification can be made by any one or more of voice notification, notification by display on the meter screen and navigation screen, and the like.

After the notification in step S31, the process proceeds to step S17 to acquire the steering angle midpoint. As described above, in the third embodiment, the notification that the stationary steering will be performed is made before the stationary steering is performed. As a result, it is possible to reduce the sense of incongruity felt by the passengers of the vehicle and the people around the vehicle with respect to the behavior of the vehicle.

In the present embodiment, a configuration has been described in which a process for notifying stationary steering is added to the control for acquiring the steering angle midpoint by stationary steering in the first embodiment. Similarly, the control of the second embodiment may be configured by adding a process of notifying the execution of the steering angle midpoint acquisition control. In this case, specifically, after the automatic driving control is turned ON in step S16 of FIG. A process for notifying that the steering angle midpoint is to be acquired may be performed.

Claims (1)

Applied to a vehicle comprising an angle sensor for detecting a steering angle of a steering mechanism of the vehicle and an electric actuator for applying a steering torque to the steering mechanism,
means for learning a steering angle midpoint of the steering mechanism;
means for performing stationary steering up to a left-right maximum steering angle when a request to start control of automatic driving of the vehicle is detected while the vehicle is stopped and the steering angle midpoint has not been learned; ,
The steering angle midpoint is calculated based on the value of the angle sensor when stationary steering is performed to the left maximum steering angle and the angle sensor value when stationary steering is performed to the right maximum steering angle. means and
A vehicle control device comprising:

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