Vehicle control device

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

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Control devices that can assist the driver in steering the vehicle or control automatic driving of the vehicle by applying steering torque from an electric actuator to the steering mechanism have been researched and developed. In controlling the steering mechanism using an electric actuator, sensors such as an angle sensor whose sensor value changes according to the 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 with the steering angle midpoint, and the difference angle between them is used as the input for steering control. When the sensor is a relative angle sensor, the steering angle midpoint is learned.

[0003] Patent Document 1 describes an estimation device that estimates the steering angle midpoint. This estimation device performs sequential Bayesian estimation for each of parameters related to the state of the steering device and parameters related to the driving state of the vehicle, and estimates the steering angle midpoint by determining that the current steering angle is the steering angle midpoint when the obtained probability satisfies a predetermined condition. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-017125 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, due to some reason such as battery clearing, the value of the steering angle midpoint may not be stored. 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 acquire the steering angle midpoint by the method described in Patent Document 1, the vehicle needs to be traveling on a straight road under predetermined conditions. Therefore, in the method of acquiring the steering angle midpoint in Patent Document 1, a vehicle stopped in a state in which the value of the steering angle midpoint is not stored cannot be started by automatic driving.

[0006] For example, in a vehicle for MaaS (Mobility as a service), it is easy to imagine a scenario in which the vehicle starts autonomous driving 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 autonomous driving even when the steering angle midpoint is not stored.

[0007] The present invention has been made in consideration of such problems, and its purpose is to provide a technology that enables a vehicle that is stopped with the steering angle midpoint not memorized to start by automatic driving. [Means for solving the problem]

[0008] The vehicle control device according to the present invention is applied to a vehicle equipped with 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. ,car When a request to start control of the automatic driving of the vehicle is detected while both are stopped, Steering mechanism When the steering angle midpoint has not been learned, a means for performing stationary steering to the maximum left and right steering angles, a value of the angle sensor when stationary steering is performed to the maximum left steering angle, and a value of the angle sensor when stationary steering is performed to the maximum right steering angle are used to calculate the steering angle midpoint. Learn by and a means for detecting the presence of the Effect of the Invention

[0009] According to the vehicle control device of the present invention, even if the vehicle is stopped with the steering angle midpoint not stored, the steering angle midpoint can be obtained before the vehicle starts, and the vehicle can start by automatic driving. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram for explaining an overview of a method for acquiring a steering midpoint in the first embodiment of the present invention. [Diagram 2] 5 is a flowchart showing an example of a control procedure executed by the control device according to the first embodiment of the present invention when a steering angle midpoint is obtained. [Diagram 3] 10 is a flowchart showing an example of a control procedure executed by a control device according to a second embodiment of the present invention when a steering angle midpoint is obtained. [Figure 4] 11 is a flowchart showing an example of a control procedure executed by a control device according to a third embodiment of the present invention when a steering angle midpoint is obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. However, when the number, quantity, amount, range, etc. of each element is mentioned in the embodiments shown below, the present invention is not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, 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.

[0012] Embodiment 1 The control device according to this 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 controlling the vehicle including steering control. The processor reads and executes the programs from the memory to realize various functions related to the control of the vehicle. The control device may be configured by multiple ECUs.

[0013] In this embodiment, in particular, the control device performs steering control to control a steering device of the vehicle when the vehicle is autonomously driven. The steering device is, for example, an electric power steering device (EPS), and includes a steering wheel for operation by a driver and a steering mechanism that connects the steering wheel and the steered wheels. The steering device also includes an electric actuator configured to apply steering torque to the steering mechanism. The electric actuator includes an electric motor and a reducer that transmits the torque of the electric motor to the steering mechanism.

[0014] During steering control, the control device receives detection results from various sensors. The various sensors include, for example, a vehicle speed sensor, a torque sensor, a motor rotation angle sensor, and a pinion angle sensor. The pinion angle sensor is an angle sensor that detects the steering angle, and detects the angle of a pinion shaft that rotates in response to the steering of the steered wheels. The control device obtains the rotation angle of the electric motor based on the detection 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.

[0015] 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 the steering control, the difference angle of the sensor value of the motor rotation angle sensor with respect to the steering angle midpoint is used as an input. In other words, the value of the steering angle midpoint is required to execute the steering control. The steering angle midpoint can be calculated, for example, by sampling the sensor value of the motor rotation angle sensor under a specified driving condition and performing statistical processing of the sampled sensor value, and the calculated value is stored in the control device as a learning value.

[0016] However, while the vehicle is stopped, the steering angle midpoint may not be stored due to some factor such as battery clearing. In response to this, the control device according to the present embodiment executes control to acquire the steering angle midpoint if the steering angle midpoint is not stored when starting the vehicle from a stopped state in autonomous driving. This makes it possible to start the vehicle in autonomous driving even when the steering angle midpoint is not stored.

[0017] Fig. 1 is a diagram showing an outline of a method for acquiring a steering angle midpoint in this embodiment. In Fig. 1, the vertical axis represents the value of the pinion angle sensor, with a left rotation direction being positive and a right rotation direction being negative. The horizontal axis represents time. Hereinafter, the method for acquiring a steering angle midpoint in this embodiment will be described with reference to Fig. 1.

[0018] When obtaining the steering angle midpoint, as shown in FIG. 1, first stationary steering is performed up to the maximum left steering angle. In other words, the target value is increased and stationary steering is performed to the left until the current value of the pinion angle sensor is saturated. The saturated value is then obtained as the left maximum value Lmax. After the current value of the pinion angle sensor is saturated, the steering direction is reversed and stationary steering is performed to the right by decreasing the target value until the current value is saturated. The saturated value is then obtained as the right maximum value Rmax. The control device finds the intermediate value of the left maximum value Lmax and right maximum value Rmax obtained in this way, and learns this intermediate value as the steering angle midpoint.

[0019] 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. This makes it possible to reduce the load on the EPS caused by stationary steering.

[0020] 2 is a flowchart showing an example of a control procedure for acquiring the steering angle midpoint, which is executed by the control device according to the present embodiment. Hereinafter, the control procedure for acquiring the steering angle midpoint will be described with reference to FIG.

[0021] As shown in Fig. 2, in step S11, it is first determined whether or not there is a request to start automatic driving control. Specifically, for example, when automatic driving control is turned ON by operating an ON / OFF switch for automatic driving control installed in the vehicle, it is determined that automatic driving control is requested. Also, when the vehicle is remotely operated, when a signal requesting automatic driving control is received remotely, it is determined that automatic driving control is requested.

[0022] If it is determined in step S11 that there is no request for automatic driving control, the process ends. On the other hand, if it is determined in step S11 that there is a request for automatic driving control, the process proceeds to step S12.

[0023] In step S12, it is determined whether the conditions for executing the automatic driving control, except for whether the steering angle midpoint has been stored, are satisfied. If the conditions for executing the automatic driving control are not satisfied, the current processing is terminated. On the other hand, if it is determined in step S12 that the conditions for executing the automatic driving control are satisfied, the processing proceeds to step S13.

[0024] In step S13, it is determined whether the steering angle midpoint has not been obtained. If the steering angle midpoint value is not stored in the control device, it is determined in step S13 that the steering angle midpoint has not been obtained, and if the steering angle midpoint is stored in the control device, it is determined in step S13 that the steering angle midpoint has not been obtained. If it is determined in step S13 that the steering angle midpoint has not been obtained, the process proceeds to step S14, where 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 steering angle midpoint has not been obtained, the process proceeds to step S15.

[0025] In step S15, it is determined whether the vehicle is currently stopped. Whether the vehicle is stopped can be determined, for example, by the value of the wheel value pulse sensor, the speed observation result of the GPS, or a combination of the wheel speed pulse sensor value and the speed observation result of the GPS. When making a determination based on the wheel speed pulse sensor value, it can be determined that the vehicle is stopped, for example, if the pulse value has not been updated for a predetermined time or more.

[0026] 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.

[0027] Next, the process proceeds to step S17. In step S17, a steering torque is applied to the steering mechanism by the steering control in the automatic driving. Then, the vehicle is stationary steered 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 process is terminated.

[0028] As described above, according to this embodiment, even if the steering angle midpoint is not stored in the control device for some reason, the steering angle midpoint can be obtained while the vehicle is stopped, and the vehicle can be started by automatic driving.

[0029] Embodiment 2 The control device according to the second embodiment has a similar configuration to the control device according to the first embodiment, except that the steering angle midpoint is acquired by steering control while the vehicle is moving slowly. Specifically, the procedure for acquiring the steering angle midpoint in the second embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing an example of the control procedure for acquiring the steering angle midpoint, which is executed by the control device according to the second embodiment.

[0030] The control shown in Fig. 3 is executed in place of the process in Fig. 2. The flowchart in Fig. 3 is the same as the flowchart in Fig. 2, except that it includes processes in steps S21 and S22 instead of step S17.

[0031] 3, if it is determined in step S15 that the vehicle is currently stopped, the process proceeds to step S21, where it is determined whether or not there is an obstacle around the vehicle. The presence or absence of an obstacle around the vehicle is determined based on information acquired by a camera, a sensor, or the like mounted on the vehicle.

[0032] Next, the process proceeds to step S16, where automatic driving control is turned ON. Next, in step S22, the steering angle midpoint is acquired. When acquiring the steering angle midpoint in step S22, the control device drives the vehicle at the lowest vehicle speed at which steering is possible. In this state, the vehicle is steered to the maximum steering angles on the left and right in the same manner as in the first embodiment, and the left maximum value Lmax and the right maximum value Rmax of the pinion angle sensor value are acquired, and their intermediate value is calculated. The calculated intermediate value is set as the steering angle midpoint. After that, the current process is terminated.

[0033] As described above, in this embodiment, after the automatic driving control is turned on, the vehicle is driven at the lowest vehicle speed at which stationary steering is possible and steering control is performed, thereby making it possible to obtain the steering angle midpoint. For example, even in a vehicle in which stationary steering is not possible due to insufficient EPS axial force, the steering angle midpoint can be obtained when the vehicle starts to travel in an automatic driving mode, and then the vehicle can start to travel in an automatic driving mode.

[0034] In the second embodiment, the vehicle is driven at the minimum steerable vehicle speed when the steering angle midpoint is acquired. However, the vehicle speed when the steering angle midpoint is acquired is not limited to the minimum steerable vehicle speed, and may be set to another speed. However, even in this case, the vehicle should be driven at a speed at which the vehicle can be stopped immediately. By controlling the steering angle midpoint acquisition while the vehicle is moving slowly in this manner, the load on the tires can be reduced.

[0035] Embodiment 3 The control device of the third embodiment performs a process of notifying the surroundings in advance when control for acquiring the steering angle midpoint is executed in the first embodiment. Fig. 4 is a flowchart for explaining a control procedure executed by the control device according to the fourth embodiment. The control process of Fig. 4 is executed in place of the control of Fig. 2 or Fig. 3. The flowchart of Fig. 4 is the same as the flowchart of Fig. 2, except that the process of step S31 is included between the process of step S16 and the process of step S17 of the flowchart of Fig. 2.

[0036] In this embodiment, as shown in Fig. 4, after the automatic driving control is turned ON in step S16, a notification that stationary steering will be performed is given in step S31. There is no limitation on the notification method here, and the notification can be given by one or more of voice notification, notification by display on the meter screen and the navigation screen, etc.

[0037] After the notification in step S31, the process proceeds to step S17, where the steering angle midpoint is acquired. In this manner, in the third embodiment, before stationary steering is executed, a notification is given that stationary steering is to be executed. This can reduce the sense of incongruity felt by the vehicle occupants and people around the vehicle with respect to the vehicle's behavior.

[0038] In this embodiment, a configuration has been described in which a process of notifying the driver of stationary steering is added to the control of acquiring the steering angle midpoint by stationary steering in the first embodiment. Similarly, a process of notifying the execution of control of acquiring the steering angle midpoint may be added to the control in the second embodiment. In this case, specifically, after the automatic driving control is turned ON in step S16 in Fig. 3, a process of notifying the driver that the steering angle midpoint will be acquired by steering control in the left and right directions may be performed before the process of step S22 in which steering at the minimum vehicle speed is started in step S22.

Claims

[Claim 1] A control device applied to a vehicle including an angle sensor that detects a steering angle of a steering mechanism of the vehicle, and an electric actuator that applies a steering torque to the steering mechanism, a means for performing stationary steering to a maximum left or right steering angle when a request to start control of automatic driving of the vehicle is detected while the vehicle is stopped and a steering angle midpoint of the steering mechanism has not been learned; A means for calculating and learning the steering angle midpoint based on a value of the angle sensor when the steering is performed to the maximum left steering angle and a value of the angle sensor when the steering is performed to the maximum right steering angle; A control device comprising:

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