VEHICLE SYSTEM

Abstract

Vehicle system with: a vehicle-mounted device; and a control device (10) which executes a program stored in a memory and is configured to: to create a timetable for the vehicle; to control the on-board equipment so that the vehicle travels according to the timetable; to predict the temperature of the on-board equipment when the vehicle is traveling according to the timetable; to limit the power output of the onboard device in order to protect the onboard device when the temperature of the onboard device is higher than a predetermined start threshold temperature; and to modify the timetable if the predicted temperature of the on-board equipment is higher than a specified temperature, where the set temperature is lower than the specified starting threshold temperature, wherein the on-board device includes a steering motor (18) which steers at least one wheel of the vehicle, where the timetable includes a planned route and a target curve condition, where the target curve state exhibits a target lateral acceleration and a target lateral jerk, wherein the control device (10) is configured: to predict the temperature of the steering motor (18) when the vehicle is traveling in the target curve state along the planned route, to obtain an upper limit of the target lateral acceleration and an upper limit of the target lateral jerk when the predicted temperature of the steering motor (18) is higher than the specified temperature, and to modify the schedule to make the target lateral acceleration lower than the upper limit of the target lateral acceleration and / or the target lateral jerk lower than the upper limit of the target lateral jerk when the predicted temperature of the steering motor (18) is higher than the set temperature.

Description

BACKGROUND Technical area

[0001] The following disclosure concerns a vehicle system. Description of the state of the art

[0002] JP 2020 - 163 984 A discloses a vehicle system that performs automated driving. In the disclosed vehicle system, a stopping position of a vehicle is determined based on a road condition detected by an external detection device, such as a camera. Based on the condition of the roadside at the determined stopping position, the vehicle system modifies a driving plan (a route, a deceleration, and the stopping position) according to which the vehicle drives to the stopping position.

[0003] US 2016 / 0185389A1 discloses a parking aid that controls a steering device to assist a vehicle in parking maneuvers by means of automatic steering. To prevent overheating of the parking aid, the vehicle system predicts the temperature of the parking aid as the vehicle moves along a path. If the predicted temperature is lower than a permissible upper limit, the control unit initiates operation; otherwise, the control unit prohibits operation along that path and assigns an alternative path.

[0004] JP 2007 - 183 205 A discloses a device for predicting temperature rise, comprising a means for predicting the temperature rise that predicts whether the temperature of an energy system will rise above a predetermined temperature along a first travel path. If the predicted temperature is higher than a predetermined temperature, a second travel path is sought along which the temperature does not rise excessively. SUMMARY OF THE REVELATION

[0005] It is common practice for a vehicle system to be designed with a protective control function that limits the operation of the onboard equipment to prevent overheating. However, when this protective control function is activated, the vehicle's control system is sometimes interrupted.

[0006] The object of the invention is to reduce the probability that a vehicle control system will be interrupted due to a limitation of an operation of an on-board device mounted on a vehicle.

[0007] This problem is solved by the features of claim 1.

[0008] In the vehicle system according to the present disclosure, a target driving state in the vehicle control system is modified in accordance with the limitation of the on-board device's operation. In a situation where the on-board device is operating to achieve the target driving state, the target driving state can, for example, be modified if it is predicted that the on-board device will reach a state in which its protective control is activated. It is therefore possible to reduce the probability that the protective control will be activated, thereby reducing the probability that the vehicle control will be interrupted. BRIEF DESCRIPTION OF THE FIGURES

[0009] The subject matter, features, advantages, and technical and industrial significance of the present disclosure will be better understood by reading the following detailed description of an embodiment in conjunction with the accompanying drawings, in which: Fig. 1 is a view that conceptually shows a vehicle system according to an embodiment of the present disclosure; Fig. 2 a flowchart that represents a program that determines whether a timetable is approved, the program being stored in a control device of the vehicle system; Fig. 3 is a flowchart that represents a timetable modification program stored in the control device; Fig. 4 is a flowchart that represents an automated driving program stored in the control device; Fig. 5 is a flowchart representing an actuator control program stored in the control device; and Fig. 6 is a view that conceptually represents a timetable. DETAILED DESCRIPTION OF THE EXECUTION FORM

[0010] With reference to the drawings, a vehicle system according to an embodiment of the present disclosure is described.

[0011] As in Fig. As shown in Figure 1, the vehicle system includes a control device 10 and a variety of on-board devices, i.e., a drive motor 12, a drive battery 14, a brake actuator 16, and a steering motor 18. The steering motor 18 is an example of a steering actuator.

[0012] The control device 10 includes, for example, an automated driving control unit 20, an electronic drive control unit (drive ECU) 22, a battery ECU 24, a brake ECU 26, and a steering ECU 28. Each of the automated driving control units 20, the drive ECU 22, the battery ECU 24, the brake ECU 26, and the steering ECU 28 essentially consists of a computer.

[0013] These devices can communicate with each other to enable the transmission and reception of information. A peripheral information acquisition device 30 and a sensor group 32 are connected to the control device 10.

[0014] The peripheral information gathering device 30 includes a camera, radar, and so on. Based on the information obtained from the camera, radar, etc., the peripheral information gathering device 30 detects an object or similar located in the vicinity of the vehicle (own vehicle) and obtains a relative positional relationship between the own vehicle and the object, a road condition, etc. The road condition includes, for example, the road's curvature and gradient.

[0015] Sensor group 32 includes a variety of sensors. For example, the variety of sensors includes a vehicle speed sensor for detecting the vehicle's speed, a voltage sensor for detecting the voltage of the drive battery 14, a speed sensor for detecting the speed of the steering motor 18, a steering angle sensor for detecting the steering angle of the vehicle's steerable wheels, an engine temperature sensor 32a for detecting the temperature of the steering motor 18, and an outside temperature sensor 32b for detecting the outside temperature.

[0016] The automated driving control unit 20 includes a timetable creation section 40 and a control command value generation section 42.

[0017] The timetable creation section 40 creates a timetable based on navigation information, including map information, and modifies the created timetable. The timetable is conceptually in Fig. Figure 6 illustrates this. The route plan includes, for example, a route candidate (also referred to as the planned route) and target driving parameters. The route candidate, which is a candidate for the route to a destination, is searched for using a known route search method and created based on the search result. The target driving parameters include, for example, a target speed, a target lateral acceleration, a target lateral jerk, and a target longitudinal acceleration, which are defined for each of a multitude of segments contained in the route candidate. When creating the route plan, the road condition and the relative positional relationship between the vehicle and the object, obtained from the peripheral information retrieval device 30, are also taken into account.

[0018] A modification of the timetable includes, for example, a change to the route candidate and a change to at least one of the target driving parameters.

[0019] The control command value generation section 42 generates control command values ​​for the drive motor 12, the brake actuator 16, the steering motor 18, etc., to enable the vehicle to drive according to the timetable created by the timetable creation section 40. The control command values ​​generated by the control command value generation section 42 are supplied to the drive ECU 22, the brake ECU 26, the steering ECU 28, etc. Furthermore, the control command value generation section 42 generates a control command value for a cooling fan of the drive battery 14 and supplies the control command value to the battery ECU 24.

[0020] The drive ECU 22 controls the drive motor 12, etc., based on the control command value. The battery ECU 24 controls the cooling fan based on the control command value. If the vehicle is a battery electric vehicle (BEV), the drive motor 12 acts as a drive source. If the vehicle is a hybrid electric vehicle (HEV), the drive source includes the drive motor 12 and an internal combustion engine. The drive ECU 22 controls the drive motor 12 to, for example, control the vehicle's speed and longitudinal acceleration.

[0021] The brake ECU 26 controls the brake actuator 16, etc., based on the control command value. The brake actuator 16 corresponds to an electric motor for driving an electric brake and / or an electromagnet of an electromagnetic valve for controlling the hydraulic pressure of a hydraulic brake. The brake ECU 26 controls the brake actuator 16 to control the deceleration of the vehicle, thereby controlling the vehicle's speed.

[0022] The steering ECU 28 controls the steering motor 18, etc., based on the control command value.

[0023] In a steering system where the torsion of a steering shaft is converted into a lateral movement of a steering rod via a rack and pinion to steer the wheels, the steering motor 18 can be a motor for twisting the steering shaft. (This motor can be referred to as a power steering motor.) In a steering system where the steerable wheels are controlled individually, the steering motor 18 can be a motor dedicated to each of the steerable wheels. The steering ECU 28 controls the steering motor 18 to, for example, control a cornering condition of the vehicle.

[0024] The steering ECU 28 executes an actuator control program at intervals of a cycle time, which is represented by a flowchart in Fig. 5 is shown.

[0025] In step 51, the steering ECU 28 receives the control command value. (Hereinafter, step 51 will be abbreviated as S51. Other steps will be abbreviated similarly.) In S52, the steering ECU 28 controls the steering motor 18, etc., based on the control command value.

[0026] The actuator control program is also executed by the drive ECU 22, the battery ECU 24 and the brake ECU 26.

[0027] In the present embodiment, the automated driving control unit 20 provides the vehicle's route plan to the drive ECU 22, the battery ECU 24, the brake ECU 26, and the steering ECU 28. The automated driving control unit 20 can provide these ECUs 22-28 with the route plan for an entire route from the current location to a destination. (The route plan for an entire route is hereinafter referred to as the "overall route route plan"). Alternatively, the automated driving control unit 20 can provide these ECUs 22-28 with a portion of the overall route route plan, such as a route candidate and target driving values ​​from the current location to a specific location where the vehicle will arrive after a certain time. The portion of the overall route route plan can include one or more segments or a part of a segment. In the following description, both the overall route route plan and the portion thereof are referred to as the route plan.

[0028] When the steering ECU 28 receives the driving plan, a predicted temperature of the steering motor 18 is determined. The predicted temperature of the steering motor 18 represents the state of the steering motor 18 when the vehicle is driving according to the driving plan; in other words, when the vehicle is driving with the target driving parameters along the route candidate. The predicted temperature of the steering motor 18 can be determined, for example, based on the following factors: the temperature of the steering motor 18 at the current time; and the amount of heat generated and the amount of heat dissipated by the steering motor 18 over a period of time during which the vehicle is driving according to the driving plan.

[0029] If the timetable includes a multitude of sections, the heat generation amount and the heat output amount of the steering motor 18 are obtained as those when the vehicle is traveling with the target driving parameters (the target driving speed, the target lateral acceleration and the target lateral jerk) that are set for each of the multitude of sections along the route candidate specified for each of the multitude of sections.

[0030] Based on the target driving parameters (such as target vehicle speed, target lateral acceleration, and target lateral jerk) set for each of the multiple sections, a target steering speed and target steering torque of the vehicle's steerable wheels are obtained. Based on the obtained target steering speed and target steering torque of the steerable wheels, a target rotational speed and target torque of the steering motor 18 are obtained in each of the multiple sections.

[0031] For example, the amount of heat generated by the steering motor 18 is determined based on the current supplied to the steering motor 18 and its load when the steering motor 18 is operated at the target speed and torque, which are determined based on the target driving parameters. The current supplied to the steering motor 18 is determined, for example, based on the voltage of a battery (as an example of an energy source supplying the steering motor 18 with electrical energy), the target speed, and the target torque of the steering motor 18. The load on the steering motor 18 is determined taking into account the road surface conditions, the target driving speed, and the air resistance or rolling resistance, which is derived, for example, from the target driving speed.The heat output of the steering motor 18 is determined, for example, based on the outside temperature detected by the outside temperature sensor 32b and the airflow speed acting on the steering motor 18. The airflow speed is determined based on the target vehicle speed.

[0032] By accumulating the heat generation and heat output amounts of the steering motor 18 for each of the plurality of sections and obtaining a difference between the heat generation and heat output amounts accumulated for the plurality of sections, the predicted temperature of the steering motor 18 when the vehicle is traveling according to the schedule is obtained using the temperature of the steering motor 18 at the present time, as detected by the engine temperature sensor 32a, as an initial value. Alternatively, the predicted temperature of the steering motor 18 when the vehicle is traveling according to the schedule can be obtained by obtaining a difference between the heat generation and heat output amounts for each of the plurality of sections and accumulating the differences obtained for the plurality of sections.

[0033] If the predicted temperature is not higher than a specified temperature, the steering ECU 28 provides a notification to the automated driving control unit 20 that the driving plan is permissible, i.e., a permissibility notification.

[0034] If, however, the predicted temperature is higher than the set temperature, the steering ECU 28 requests the automated driving control unit 20 to modify the driving plan, i.e., to replan the driving plan. For example, the automated driving control unit 20 modifies the driving plan by reducing a maximum value of the target lateral acceleration and / or target lateral jerk, which are set for at least one of the plurality of sections, or by reducing an average value of the target lateral acceleration and / or target lateral jerk, which are set for at least one of the plurality of sections.

[0035] An electric motor such as the steering motor 18 is typically designed so that a protective controller is activated to limit the motor's power output if its temperature exceeds a set threshold temperature. This prevents overheating due to prolonged operation. The set temperature described above is the temperature at which limiting the operation of the steering motor 18 is deemed necessary. For example, the set temperature could be a value determined based on the protective controller's start threshold temperature. The set temperature could be equal to or lower than the start threshold temperature.

[0036] If the predicted temperature is higher than the set temperature, the steering ECU 28 can receive an upper limit for the target lateral jerk (upper limit for the target steering speed) and / or an upper limit for the target lateral acceleration (upper limit for the target steering torque), which prevents the temperature of the steering motor 18 from reaching the set temperature. In this case, the steering ECU 28 can provide the upper limit for the target lateral jerk and / or the upper limit for the target lateral acceleration to the scheduling section 40 of the automated driving control unit 20, in addition to the request to reschedule.

[0037] The steering ECU 28 repeatedly executes a program to determine, each time a specified time interval has elapsed, whether a driving plan is permissible or not. The program is represented by a flowchart in Fig. 2 shown.

[0038] In S1, the steering ECU 28 receives the driving plan supplied by the automated driving control unit 20. In S2, the steering ECU 28 receives the target operating state of the steering motor 18 based on the target lateral acceleration and target lateral jerk contained in the driving plan. The target operating state of the steering motor 18 is represented, for example, by the target speed and target torque. In S3, the steering ECU 28 determines the predicted temperature of the steering motor 18. In S4, the steering ECU 28 determines whether the driving plan is executable; in other words, the steering ECU 28 determines whether the execution of the driving plan is permissible. In particular, the steering ECU 28 determines whether the predicted temperature is not higher than the specified temperature. If a positive determination (YES) is made in S4, the control flow passes to S5, in which the steering ECU 28 transmits the admissibility notification to the automated driving control unit 20 that the driving plan is admissible.If a negative determination (NO) is made in S4, the control flow, on the other hand, passes to S6, in which the steering ECU 28 requests the automated driving control unit 20 to replan the driving schedule in order to reduce the amount of heat generated by the steering motor 18.

[0039] The automated driving control unit 20 executes a timetable modification program, which is represented by a flowchart in Fig. 3 is shown.

[0040] In S11, it is determined whether the request to replan the timetable has been made. If a negative determination (NO) is made in S11, S12 is not implemented. Conversely, if a positive determination (YES) is made in S11, the timetable is modified in S12. Timetable creation section 40 modifies the timetable to reduce the predicted temperature of the steering motor 18. For example, timetable creation section 40 modifies the timetable to reduce the target lateral acceleration and / or target lateral jerk in one or more of the multiple sections. The timetable can be modified to reduce the target lateral acceleration and / or target lateral jerk to less than or equal to their respective upper limits.

[0041] Automated driving is carried out according to the permitted timetable or the modified timetable. The automated driving control unit 20 executes an automated driving program, which is defined by a flowchart in Fig. 4 is shown.

[0042] S21 determines whether the automated driving control unit 20 has received the approval notification for the driving schedule. If a negative determination (NO) is made in S21, S22 determines whether the driving schedule has been modified. If a positive determination (YES) is made in either S21 or S22, the control flow continues to S23, where the control command values ​​are generated in accordance with the driving schedule and supplied to the steering ECU 28, and so on. The steering ECU 28 executes the control flow according to the flow diagram of Fig. The actuator control program shown in section 5 is executed, and the steering motor 18 is controlled based on the control command value, so that automated driving is carried out according to the schedule.

[0043] In the embodiment described above, if there is a possibility that the protective control for the steering motor 18 will be activated, the driving plan is rescheduled and the power of the steering motor 18 is limited. This reduces the probability that automated driving will be interrupted due to overheating of the steering motor 18.

[0044] After the driving plan has been modified, it can be transmitted again to the steering ECU 28. For example, the driving plan can be modified repeatedly until the steering ECU 28 transmits the driving plan's compliance notification to the automated driving control unit 20. In this case, automated driving is carried out according to the compliance driving plan.

[0045] In the embodiment described above, a prediction section is formed by sections of the steering ECU 28 of the control device 10 that, for example, store and execute S3. A determination section is formed by sections of the steering ECU 28 of the control device 10 that, for example, store and execute S4. A notification section is formed by sections of the steering ECU 28 of the control device 10 that, for example, store and execute S6. A modification section is formed by sections of the automated driving control unit 20 of the control device 10 that store and execute the driving plan modification program, which is defined, for example, by the flowchart in Fig. 3 is shown. A steering actuator control section, for example, is represented by sections of the automated driving control unit 20, which are shown in the flowchart in Fig. 4. Store and execute the automated driving program shown, and through sections of the steering ECU 28, which are shown in the flowchart in Fig. 5. Save and execute the actuator control program shown.

[0046] The control device 10 can consist of a single computer.

[0047] Part or all of the program for determining whether the timetable is permissible or not can be executed by the automatic driving control unit 20.

[0048] The timetable can be replanned to prevent overheating not only of the steering motor 18, but also of the drive motor 12 and / or the brake actuator 16.

[0049] The target driving state of the vehicle is not limited to the state represented by the driving plan in automated driving. The target driving state of the vehicle can, for example, be a target driving state in the context of the driving assistance control system.

[0050] It is understood that the present disclosure is not limited to the details of the embodiment shown, but can be carried out with various changes and modifications that may occur to the person skilled in the art without deviating from the spirit and scope of the disclosure.

Claims

[1] Vehicle system with: a vehicle-mounted device; and a control device (10) which executes a program stored in a memory and is configured to: to create a timetable for the vehicle; to control the on-board equipment so that the vehicle travels according to the timetable; to predict the temperature of the on-board equipment when the vehicle is traveling according to the timetable; to limit the power output of the onboard device in order to protect the onboard device when the temperature of the onboard device is higher than a predetermined start threshold temperature; and to modify the timetable if the predicted temperature of the on-board equipment is higher than a specified temperature, where the set temperature is lower than the specified starting threshold temperature, wherein the on-board device includes a steering motor (18) which steers at least one wheel of the vehicle, where the timetable includes a planned route and a target curve condition, where the target curve state exhibits a target lateral acceleration and a target lateral jerk, wherein the control device (10) is configured: to predict the temperature of the steering motor (18) when the vehicle is traveling in the target curve state along the planned route, to obtain an upper limit of the target lateral acceleration and an upper limit of the target lateral jerk when the predicted temperature of the steering motor (18) is higher than the set temperature, and to modify the schedule to make the target lateral acceleration lower than the upper limit of the target lateral acceleration and / or the target lateral jerk lower than the upper limit of the target lateral jerk when the predicted temperature of the steering motor (18) is higher than the set temperature.

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