Patent Application
20230110521
This nonprovisional application is based on Japanese Patent Application No. 2021-157625 filed with the Japan Patent Office on Sep. 28, 2021, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to control of a vehicle during autonomous driving.
An autonomous driving system for controlling a vehicle to travel without requiring an operation by a user has recently been developed. For being mountable on an existing vehicle, the autonomous driving system may be provided, for example, separately from the vehicle with an interface being interposed.
For example, Japanese Patent Laying-Open No. 2018-132015 discloses as such an autonomous driving system, a technique that allows addition of an autonomous driving function without great modification to an existing vehicle platform, by providing an electronic control unit (ECU) that manages motive power of a vehicle and an ECU for autonomous driving independently of each other.
In control of a steering angle in accordance with a request during autonomous driving of a vehicle, when the steering angle abruptly changes with sudden increase in requested amount of the steering angle, stability of the vehicle may become poor.
An object of the present disclosure is to provide a vehicle on which an autonomous driving system is mountable, a method of controlling a vehicle, and a vehicle control interface box that allow improvement in stability of steering during autonomous driving.
A vehicle according to one aspect of the present disclosure is a vehicle on which an autonomous driving system is mountable. The vehicle includes a vehicle platform that carries out vehicle control in accordance with a command from the autonomous driving system. The vehicle platform includes a base vehicle and a vehicle control interface box that interfaces between the autonomous driving system and the base vehicle. From the autonomous driving system to the base vehicle, a wheel steer angle command that requests a steer angle of a steering wheel is transmitted through the vehicle control interface box. From the base vehicle to the autonomous driving system, a signal indicating the steer angle is transmitted. The steer angle requested in the wheel steer angle command is set not to exceed a restriction range of a rate of the steer angle that is set based on a velocity of the vehicle.
Thus, the wheel steer angle command is set not to exceed the restriction range of the rate of the steer angle. Therefore, even when a requested amount of the wheel steer angle of the steering wheel suddenly increases, abrupt change in steering angle is suppressed. Therefore, degradation of stability of the vehicle can be suppressed.
In one embodiment, the restriction range is set such that magnitude of an upper limit value of the rate when the velocity of the vehicle is set to a first velocity is smaller than magnitude of an upper limit value of the rate when the velocity of the vehicle is set to a second velocity lower than the first velocity.
Thus, since magnitude of the upper limit value of the rate of the steer angle is smaller as the velocity of the vehicle is higher, abrupt change in steer angle is suppressed. Therefore, degradation of stability of the vehicle can be suppressed.
A method of controlling a vehicle according to another aspect of the present disclosure is a method of controlling a vehicle on which an autonomous driving system is mountable. The vehicle includes a vehicle platform that carries out vehicle control in accordance with a command from the autonomous driving system. The vehicle platform includes a base vehicle and a vehicle control interface box that interfaces between the autonomous driving system and the base vehicle. The method includes transmitting a wheel steer angle command that requests a steer angle of a steering wheel from the autonomous driving system to the base vehicle through the vehicle control interface box, transmitting a signal indicating the steer angle from the base vehicle to the autonomous driving system, and setting the steer angle requested in the wheel steer angle command not to exceed a restriction range of a rate of the steer angle that is set based on a velocity of the vehicle.
In one embodiment, the restriction range is set such that magnitude of an upper limit value of the rate when the velocity of the vehicle is set to a first velocity is smaller than magnitude of an upper limit value of the rate when the velocity of the vehicle is set to a second velocity lower than the first velocity.
A vehicle control interface box according to yet another aspect of the present disclosure is a vehicle control interface box that interfaces between an autonomous driving system and a vehicle on which the autonomous driving system is mountable, the vehicle including a vehicle platform that carries out vehicle control in accordance with a command from the autonomous driving system. The vehicle platform includes a base vehicle. The vehicle control interface box transmits a wheel steer angle command that requests a steer angle of a steering wheel from the autonomous driving system to the base vehicle. The vehicle control interface box transmits a signal indicating the steer angle from the base vehicle to the autonomous driving system. The steer angle requested in the wheel steer angle command is set not to exceed a restriction range of a rate of the steer angle that is set based on a velocity of the vehicle.
In one embodiment, the restriction range is set such that magnitude of an upper limit value of the rate when the velocity of the vehicle is set to the first velocity is smaller than magnitude of an upper limit value of the rate when the velocity of the vehicle is set to a second velocity lower than the first velocity.
The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.
An embodiment of the present disclosure will be described below in detail with reference to the drawings. The same or corresponding elements in the drawings have the same reference characters allotted and description thereof will not be repeated.
Vehicle 10 can carry out autonomous driving in accordance with control requests (commands) from ADK 200 attached to VP 120. Though
ADK 200 includes an autonomous driving system (which is denoted as “ADS” below) 202 for autonomous driving of vehicle 10. For example, ADS 202 creates a driving plan of vehicle 10 and outputs various commands (control requests) for travel of vehicle 10 in accordance with the created driving plan to VP 120 in accordance with an application program interface (API) defined for each command. ADS 202 receives various signals indicating statuses (vehicle statuses) of VP 120 from VP 120 in accordance with the API defined for each signal and has the received vehicle status reflected on creation of the driving plan. A detailed configuration of ADS 202 will be described later.
VP 120 includes base vehicle 100 and a vehicle control interface box (which is denoted as “VCIB” below) 111 that implements a vehicle control interface provided within base vehicle 100.
VCIB 111 can communicate with ADK 200 over a controller area network (CAN). VCIB 111 receives various commands from ADK 200 or outputs a status of VP 120 to ADK 200 by executing a prescribed API defined for each communicated signal. When VCIB 111 receives a control request from ADK 200, it outputs a control command corresponding to the control request to a system corresponding to the control command through an integrated control manager 115. VCIB 111 obtains various types of information on base vehicle 100 from various systems through integrated control manager 115 and outputs the status of base vehicle 100 as the vehicle status to ADK 200.
VP 120 includes various systems and various sensors for controlling base vehicle 100. As VP 120 carries out various types of vehicle control in accordance with a control request from ADK 200 (more specifically, ADS 202), autonomous driving of vehicle 10 is carried out. VP 120 includes, for example, a brake system 121, a steering system 122, a powertrain system 123, an active safety system 125, and a body system 126.
Brake system 121 is configured to control a plurality of braking apparatuses provided in wheels of base vehicle 100. The braking apparatus includes, for example, a disc brake system that is operated with a hydraulic pressure regulated by an actuator.
For example, wheel speed sensors 127A and 127B are connected to brake system 121. Wheel speed sensor 127A is provided, for example, in a front wheel of base vehicle 100 and detects a rotation speed of the front wheel. Wheel speed sensor 127A outputs the rotation speed of the front wheel to brake system 121. Wheel speed sensor 127B is provided, for example, in a rear wheel of base vehicle 100 and detects a rotation speed of the rear wheel. Wheel speed sensor 127B outputs the rotation speed of the rear wheel to brake system 121. Wheel speed sensors 127A and 127B each provide a pulsed signal as an output value (a pulse value). The rotation speed can be calculated based on the number of pulses in the pulsed signal. Brake system 121 outputs the rotation speed of each wheel to VCIB 111 as one of pieces of information included in a vehicle status.
Brake system 121 generates a braking command to a braking apparatus in accordance with a prescribed control request outputted from ADK 200 through VCIB 111 and integrated control manager 115 and controls the braking apparatus based on the generated braking command.
Steering system 122 is configured to control a steering angle of a steering wheel of vehicle 10 with a steering apparatus. The steering apparatus includes, for example, rack-and-pinion electric power steering (EPS) that allows adjustment of a steering angle by an actuator.
A pinion angle sensor 128 is connected to steering system 122. Pinion angle sensor 128 detects an angle of rotation of a pinion gear (a pinion angle) coupled to a rotation shaft of the actuator included in the steering apparatus. Pinion angle sensor 128 provides a detected pinion angle to steering system 122. Steering system 122 provides the pinion angle as one of pieces of information included in the vehicle status to VCIB 111.
Steering system 122 generates a steering command to the steering apparatus in accordance with a prescribed control request outputted from ADK 200 through VCIB 111 and integrated control manager 115. Steering system 122 controls the steering apparatus based on the generated steering command.
Powertrain system 123 controls an electric parking brake (EPB) provided in at least one of a plurality of wheels provided in vehicle 10, a P-Lock apparatus provided in a transmission of vehicle 10, a shift apparatus configured to select any shift range from among a plurality of shift ranges, and a drive source of vehicle 10. Detailed description will be given later.
Active safety system 125 detects an obstacle (an obstacle or a human) in front or in the rear with the use of a camera 129A and radar sensors 129B and 129C. When active safety system 125 determines that there is possibility of collision based on a distance to the obstacle or the like and a direction of movement of vehicle 10, it outputs a braking command to brake system 121 through integrated control manager 115 so as to increase braking force.
Body system 126 is configured to control, for example, components such as a direction indicator, a horn, or a wiper, depending on a status of travel or an environment around vehicle 10. Body system 126 controls the above-described component in accordance with a prescribed control request outputted from ADK 200 through VCIB 111 and integrated control manager 115.
Vehicle 10 may be adopted as one of constituent elements of a mobility as a service (MaaS) system. The MaaS system further includes, for example, a data server, a mobility service platform (which is denoted as “MSPF” below), and autonomous driving related mobility services (none of which is shown), in addition to vehicle 10.
Vehicle 10 further includes a data communication module (DCM) (not shown) as a communication interface (I/F) to wirelessly communicate with the data server described above. The DCM outputs various types of vehicle information such as a speed, a position, or an autonomous driving state to the data server. The DCM receives from the autonomous driving related mobility services through the MSPF and the data server, various types of data for management of travel of an autonomous driving vehicle including vehicle 10 in the mobility services.
The MSPF is an integrated platform to which various mobility services are connected. In addition to autonomous driving related mobility services, not-shown various mobility services (for example, various mobility services provided by a ride-share company, a car-sharing company, an insurance company, a rent-a-car company, and a taxi company) are connected to the MSPF. Various mobility services including mobility services can use various functions provided by the MSPF by using APIs published on the MSPF, depending on service contents.
The autonomous driving related mobility services provide mobility services using an autonomous driving vehicle including vehicle 10. The mobility services can obtain operation control data of vehicle 10 that communicates with the data server or information stored in the data server from the MSPF by using the APIs published on the MSPF. The mobility services transmit data for managing an autonomous driving vehicle including vehicle 10 to the MSPF by using the API.
The MSPF publishes APIs for using various types of data on vehicle statuses and vehicle control necessary for development of the ADS. An ADS provider can use as the APIs, the data on the vehicle statuses and vehicle control necessary for development of the ADS stored in the data server.
During autonomous driving of the vehicle, compute assembly 210 obtains information indicating an environment around the vehicle and information indicating a pose, a behavior, and a position of the vehicle from various sensors which will be described later, and obtains a vehicle status from VP 120 which will be described later through VCIB 111 and sets a next operation (acceleration, deceleration, or turning) of vehicle 10. Compute assembly 210 outputs various commands for realizing a set next operation of the vehicle to VCIB 111. Compute assembly 210 includes communication modules 210A and 210B. Communication modules 210A and 210B are configured to communicate with VCIB 111.
HMI 230 presents information to a user and accepts an operation by the user during autonomous driving, during driving requiring an operation by the user, or at the time of transition between autonomous driving and driving requiring an operation by the user. HMI 230 is constructed to be connected to an input and output apparatus such as a touch panel display, a display apparatus, and an operation apparatus provided in base vehicle 100.
Sensors for perception 260 include sensors that perceive an environment around vehicle 10 and include, for example, at least one of laser imaging detection and ranging (LIDAR), a millimeter-wave radar, and a camera.
The LIDAR refers to a distance measurement apparatus that measures a distance based on a time period from emission of pulsed laser beams (infrared rays) until return of the laser beams reflected by an object. The millimeter-wave radar is a distance measurement apparatus that measures a distance or a direction to an object by emitting radio waves short in wavelength to the object and detecting radio waves that return from the object. The camera is arranged, for example, on a rear side of a room mirror in a compartment and used for shooting an image of the front of the vehicle. Information obtained by sensors for perception 260 is outputted to compute assembly 210. As a result of image processing by artificial intelligence (AI) or an image processing processor onto images or video images shot by the camera, another vehicle, an obstacle, or a human in front of the vehicle can be recognized.
Sensors for pose 270 include sensors that detect a pose, a behavior, or a position of the vehicle, and include, for example, an inertial measurement unit (IMU) or a global positioning system (GPS).
The IMU detects, for example, an acceleration in a front-rear direction, a lateral direction, and a vertical direction of the vehicle and an angular speed in a roll direction, a pitch direction, and a yaw direction of the vehicle. The GPS detects a position of vehicle 10 based on information received from a plurality of GPS satellites that orbit the Earth. Information obtained by sensors for pose 270 is outputted to compute assembly 210.
Sensor cleaning 290 is configured to remove soiling attached to various sensors during traveling of the vehicle. Sensor cleaning 290 removes soiling attached to a lens of the camera or a portion from which laser beams or radio waves are emitted, for example, with a cleaning solution or a wiper.
VCIB 111 includes a VCIB 111A and a VCIB 111B. Each of VCIBs 111A and 111B contains a central processing unit (CPU) and a memory (for example, a read only memory (ROM) and a random access memory (RAM)), neither of which is shown. Though VCIB 111A is equivalent in function to VCIB 111B, it is partially different in a plurality of systems connected to the VCIBs that make up VP 120.
VCIBs 111A and 111B are communicatively connected to communication modules 210A and 210B of compute assembly 210, respectively. VCIB 111A and VCIB 111B are communicatively connected to each other.
VCIBs 111A and 111B each relay various commands corresponding to control requests from ADS 202 and output them as control commands to a corresponding system of VP 120. More specifically, each of VCIB 111A and VCIB 111B uses various commands provided from ADS 202 based on information (for example, an API) such as a program stored in the memory to generate a control command to be used for control of a corresponding system of VP 120 and outputs the control command to the corresponding system. VCIBs 111A and 111B each relay vehicle information provided from each system of VP 120 and provide the vehicle information as a vehicle status to ADS 202. The information indicating the vehicle status may be information identical to the vehicle information or may be information extracted from the vehicle information to be used for processing performed by ADS 202.
As VCIBs 111A and 111B equivalent in function relating to an operation of at least one of (for example, braking or steering) systems are provided, control systems between ADS 202 and VP 120 are redundant. Thus, when some kind of failure occurs in a part of the system, the function (turning or stopping) of VP 120 can be maintained by switching between the control systems as appropriate or disconnection of a control system where failure has occurred.
Brake system 121 includes brake systems 121A and 121B. Steering system 122 includes steering systems 122A and 122B. Powertrain system 123 includes an EPB system 123A, a P-Lock system 123B, and a propulsion system 124.
VCIB 111A is communicatively connected to brake system 121A, steering system 122A, EPB system 123A, P-Lock system 123B, propulsion system 124, and body system 126 of the plurality of systems of VP 120 through a communication bus.
VCIB 111B is communicatively connected to brake system 121B, steering system 122B, and P-Lock system 123B of the plurality of systems of VP 120 through a communication bus.
Brake systems 121A and 121B are configured to control a plurality of braking apparatuses provided in wheels of the vehicle. Brake system 121A may be equivalent in function to brake system 121B, or one of them may be configured to independently control braking force of each wheel during travel of the vehicle and the other thereof may be configured to control braking force such that equal braking force is generated in the wheels during travel of the vehicle.
Brake systems 121A and 121B generate braking commands to the braking apparatuses in accordance with a control request outputted from ADS 202 through VCIB 111A and VCIB 111B, respectively. For example, brake systems 121A and 121B control the braking apparatuses based on a braking command generated in one of the brake systems, and when a failure occurs in that brake system, the braking apparatuses are controlled based on a braking command generated in the other brake system.
Steering systems 122A and 122B are configured to control a steering angle of a steering wheel of vehicle 10 with a steering apparatus. Steering system 122A is similar in function to steering system 122B.
Steering systems 122A and 122B generate steering commands to the steering apparatus in accordance with a control request outputted from ADS 202 through VCIB 111A and VCIB 111B, respectively. For example, steering systems 122A and 122B control the steering apparatus based on the steering command generated in one of the steering systems, and when a failure occurs in that steering system, the steering apparatus is controlled based on a steering command generated in the other steering system.
EPB system 123A is configured to control the EPB. The EPB fixes a wheel by an operation of an actuator. The EPB, for example, activates with an actuator, a drum brake for a parking brake provided in at least one of a plurality of wheels provided in vehicle 10 to fix the wheel, or activates a braking apparatus to fix a wheel with an actuator capable of regulating a hydraulic pressure to be supplied to the braking apparatus separately from brake systems 121A and 121B.
EPB system 123A controls the EPB in accordance with a control request outputted from ADS 202 through VCIB 111A.
P-Lock system 123B is configured to control a P-Lock apparatus. The P-Lock apparatus fits a protrusion provided at a tip end of a parking lock pawl, a position of which is adjusted by an actuator, into a tooth of a gear (locking gear) provided as being coupled to a rotational element in the transmission of vehicle 10. Rotation of an output shaft of the transmission is thus fixed so that fixing of rotation of the wheel (which is also referred to as “fixing of wheels” below) of a drive wheel is carried out.
P-Lock system 123B controls the P-Lock apparatus in accordance with a control request provided from ADS 202 through VCIB 111A. For example, when the control request provided from ADS 202 through VCIB 111A includes a control request to set the shift range to a parking range (which is denoted as a P range below), P-Lock system 123B activates the P-Lock apparatus, and when the control request includes a control request to set the shift range to a shift range other than the P range, it deactivates the P-Lock apparatus.
Propulsion system 124 is configured to switch a shift range with the use of a shift apparatus and to control driving force of vehicle 10 in a direction of movement of vehicle 10 that is generated from a drive source. Switchable shift ranges include, for example, the P range, a neutral range (which is denoted as an N range below), a forward travel range (which is denoted as a D range below), and a rearward travel range (which is denoted as an R range below). The drive source includes, for example, a motor generator and an engine.
Propulsion system 124 controls the shift apparatus and the drive source in accordance with a control request provided from ADS 202 through VCIB 111A. For example, when a control request provided from ADS 202 through VCIB 111A includes a control request to set the shift range to the P range, propulsion system 124 controls the shift apparatus to set the shift range to the P range.
Active safety system 125 is communicatively connected to brake system 121A. As described above, active safety system 125 detects an obstacle (an obstacle or a human) in front by using camera 129A and radar sensor 129B, and when it determines that there is possibility of collision based on a distance to the obstacle, it outputs a braking command to brake system 121A so as to increase braking force.
Body system 126 controls components such as a direction indicator, a horn, or a wiper in accordance with a control request provided from ADS 202 through VCIB 111A.
An operation apparatus manually operable by a user for the braking apparatus, the steering apparatus, the EPB, the P-Lock apparatus, the shift apparatus, and the drive source described above may separately be provided.
Various commands corresponding to control requests provided from ADS 202 to VCIB 111 include a propulsion direction command requesting switching of the shift range, an immobilization command requesting activation or deactivation of the EPB and the P-Lock apparatus, an acceleration command requesting acceleration or deceleration of vehicle 10, a wheel steer angle command requesting a wheel steer angle of a steering wheel, an autonomization command requesting switching of an autonomous state between an autonomous mode and a manual mode, and a standstill command requesting keeping on stationary or keeping off stationary of the vehicle.
For example, when an autonomous mode is selected as the autonomous state by an operation by the user onto HMI 230 in vehicle 10 configured as above, autonomous driving is carried out. During autonomous driving, ADS 202 initially creates a driving plan as described above. Examples of the driving plan include a plurality of plans relating to operations of vehicle 10 such as a plan to continue straight travel, a plan to turn left or right at a prescribed intersection on a predetermined travel path, and a plan to change a travel lane to a lane different from the lane where the vehicle currently travels.
ADS 202 extracts a controllable physical quantity (for example, an acceleration or a deceleration, and a wheel steer angle) necessary for operations of vehicle 10 in accordance with the created driving plan. ADS 202 splits the physical quantity for each execution cycle time of the API. ADS 202 executes the API with the use of the resultant physical quantity and outputs various commands to VCIB 111. Furthermore, ADS 202 obtains a vehicle status (for example, an actual direction of movement of vehicle 10 and a state of fixation of the vehicle) from VP 120 and creates again the driving plan on which the obtained vehicle status is reflected. ADS 202 thus allows autonomous driving of vehicle 10.
In control of a wheel steer angle (steering angle) in accordance with a request during autonomous driving of vehicle 10, when the steering angle abruptly changes with sudden increase in requested amount of the wheel steer angle, stability of vehicle 10 may become poor.
In the present embodiment, in steering in accordance with a wheel steer angle command set based on a wheel steer angle of the front wheel which is the steering wheel, it is assumed that the wheel steer angle requested in the wheel steer angle command is set not to exceed a restriction range of a rate of the wheel steer angle that is set based on the velocity of vehicle 10 (which is also denoted as the vehicle velocity).
The wheel steer angle command is thus set not to exceed the restriction range of the rate of the steer angle. Therefore, even when the requested amount of the wheel steer angle of the steering wheel suddenly increases, abrupt change in steering angle is suppressed. Therefore, degradation of stability of vehicle 10 can be suppressed.
Processing performed by ADS 202 (more specifically, compute assembly 210) in the present embodiment will be described below with reference to
In step (the step being denoted as S below) 11, ADS 202 determines whether or not vehicle 10 is traveling straight. For example, when a while line indicating a travel lane over which vehicle 10 travels is a straight line having a prescribed length or longer, ADS 202 may determine that vehicle 10 is traveling straight, or when records of movement of vehicle 10 based on the GPS indicate a straight line having a prescribed length or longer, ADS 202 may determine that vehicle 10 is traveling straight. When vehicle 10 is determined as traveling straight (YES in S11), the process proceeds to S12.
In S12, ADS 202 obtains the wheel steer angle of the front wheel which is the steering wheel. ADS 202 obtains the wheel steer angle of the front wheel based on a vehicle status provided from base vehicle 100 through vehicle control interface box 111. Base vehicle 100 (specifically, steering system 122) obtains a pinion angle based on a result of detection by pinion angle sensor 128 and calculates the wheel steer angle of the front wheel based on the obtained pinion angle. Base vehicle 100 calculates the wheel steer angle of the front wheel each time a predetermined period elapses, and provides the calculated wheel steer angle of the front wheel as one of pieces of information included in the vehicle status to ADS 202 through vehicle control interface box 111.
In S13, ADS 202 sets a reference value. ADS 202 sets a value expressing the obtained wheel steer angle of the front wheel as the reference value. When vehicle 10 is determined as not traveling straight (NO in S11), this process ends.
For example, when switching to the autonomous mode is made after the reference value is set, ADS 202 sets an initial value of the wheel steer angle command corresponding to the steering angle set in accordance with the driving plan, based on the reference value.
Processing performed in ADS 202 in the autonomous mode will be described with reference to
In S21, ADS 202 determines whether or not an autonomous state has been set to an autonomous mode. ADS 202 determines whether or not the autonomous state has been set to the autonomous mode, for example, based on a status of a flag indicating the autonomous mode. The flag indicating the autonomous mode is turned on, for example, when an operation to carry out autonomous driving onto HMI 230 by the user is accepted and turned off when the autonomous mode is canceled and switching to the manual mode is made in response to an operation by the user or in accordance with a condition of drive. When the autonomous state is determined as having been set to the autonomous mode (YES in S21), the process proceeds to S22.
In S22, ADS 202 sets the initial value of the wheel steer angle command. ADS 202 sets the initial value of the wheel steer angle command in accordance with the driving plan. For example, when the driving plan is a driving plan to travel straight, ADS 202 sets a relative value between a current value of the wheel steer angle and the reference value as the initial value of the wheel steer angle command. For example, when the driving plan is a driving plan to turn left at a predetermined steering angle, ADS 202 sets a relative value between the current value of the wheel steer angle and a value calculated by adding a value corresponding to the predetermined steering angle to the reference value as the initial value of the wheel steer angle command. For example, when the driving plan is a driving plan to turn right at a predetermined steering angle, ADS 202 sets a relative value between the current value of the wheel steer angle and a value calculated by subtracting a value corresponding to the predetermined steering angle from the reference value as the initial value of the wheel steer angle command.
In S23, ADS 202 obtains a wheel steer angle rate limitation of the front wheel which is the steering wheel. ADS 202 sets the wheel steer angle rate limitation based on relation between a vehicle velocity and a wheel steer angle rate limitation as shown in
For example,
ADS 202 obtains information on the vehicle velocity of vehicle 10 as a vehicle status from VP 120. For example, information on a velocity of vehicle 10 (a velocity in the direction of travel of vehicle 10) calculated based on a wheel speed obtained by wheel speed sensor 127A or wheel speed sensor 127B is outputted as the vehicle status from base vehicle 100 through VCIB 111 to ADS 202. ADS 202 obtains the wheel steer angle rate limitation based on the obtained vehicle velocity and the above-described relation between the vehicle velocity and the wheel steer angle rate limitation shown in
In S24, ADS 202 determines whether or not magnitude of the initial value of the wheel steer angle command is larger than the wheel steer angle limitation. ADS 202 obtains, for example, an absolute value of the initial value of the wheel steer angle command as magnitude of the initial value of the wheel steer angle command. ADS 202 calculates the wheel steer angle limitation from the wheel steer angle rate limitation. ADS 202 calculates the wheel steer angle limitation, for example, by multiplying the wheel steer angle rate limitation by a value corresponding to a control cycle (computation cycle). When the magnitude of the initial value of the wheel steer angle command is determined as being larger than the wheel steer angle limitation (YES in S24), the process proceeds to S25.
In S25, ADS 202 sets the wheel steer angle command based on the wheel steer angle limitation. In other words, ADS 202 changes only the magnitude of the initial value to the wheel steer angle limitation, with the sign of the wheel steer angle command being maintained, and sets the resultant value as the wheel steer angle command. When the magnitude of the initial value of the wheel steer angle command is determined as being equal to or smaller than the wheel steer angle limitation (NO in S24), the process proceeds to S26.
In S26, ADS 202 transmits the set wheel steer angle command to VCIB 111.
Processing performed in VCIB 111 (more specifically, VCIB 111A or VCIB 111B) will now be described with reference to
In S31, VCIB 111 determines whether or not it has received the wheel steer angle command from ADS 202. When the VCIB is determined as having received the wheel steer angle command (YES in S31), the process proceeds to S32.
In S32, VCIB 111 controls the steering apparatus. VCIB 111 controls the steering apparatus in accordance with the received wheel steer angle command. In other words, VCIB 111 controls the steering apparatus to steer the vehicle by the relative value of the steering angle indicated in the wheel steer angle command.
In S33, VCIB 111 obtains the front wheel steer angle. In S34, VCIB 111 transmits the obtained wheel steer angle as one of pieces of information of the vehicle statuses to ADS 202.
An operation of ADS 202 based on the structure and the flowchart as above will be described.
For example, when vehicle 10 travels straight (YES in S11), the front wheel steer angle is obtained from base vehicle 100 (S12) and the value indicating the obtained front wheel steer angle is set as the reference value (S13).
For example, when the autonomous mode has been set as the autonomous state (YES in S21), the initial value of the wheel steer angle command is set in accordance with the driving plan (S22). At this time, a relative value from the current value of the wheel steer angle to a value corresponding to the steering angle in accordance with the driving plan is set as the initial value of the wheel steer angle command.
Thereafter, the wheel steer angle rate limitation is obtained based on the vehicle velocity (S23). Specifically, the vehicle velocity is obtained from base vehicle 100, and the wheel steer angle rate limitation is obtained based on the obtained vehicle velocity and the relation between the vehicle velocity and the limitation shown in
When VCIB 111 receives the wheel steer angle command (YES in S31), the steering apparatus of base vehicle 100 is controlled (S32). Thereafter, the wheel steer angle is obtained (S33) and the wheel steer angle is transmitted to ADS 202 (S34).
As set forth above, according to vehicle 10 in the present embodiment, the wheel steer angle command is set not to exceed the restriction range of the rate of the steer angle. Therefore, even when the requested amount of the wheel steer angle of the front wheel which is the steering wheel suddenly increases, abrupt change in steering angle is suppressed. Therefore, degradation of stability of vehicle 10 can be suppressed. Therefore, a vehicle on which an autonomous driving system is mountable, a method of controlling a vehicle, and a vehicle control interface box that achieve improvement in stability of steering during autonomous driving can be provided.
Since magnitude of the upper limit value of the wheel steer angle rate is smaller as the vehicle velocity is higher, abrupt change in steering angle is suppressed. Therefore, degradation of stability of the vehicle can be suppressed.
A modification will be described below.
Though VCIB 111A or VCIB 111B is described as performing the processing shown in the flowchart in
Though vehicle control interface box 111 is described as performing the processing shown in the flowchart in
The entirety or a part of the modification may be carried out as being combined as appropriate.
API Specification for TOYOTA Vehicle Platform
Ver. 1.1
1. Introduction
1.1. Purpose of this Specification
This document is an API specification of vehicle control interface for Autono-MaaS vehicles and contains outline, the way to use and note of APIs.
1.2. Target Vehicle
This specification is applied to the Autono-MaaS vehicles defined by [Architecture Specification for TOYOTA Vehicle Platform attached with Automated Driving System].
1.3. Definition of Term
2. Structure
2.1. Overall Structure of Autono-MaaS Vehicle
The overall structure of Autono-MaaS is shown (
2.2. System Structure of Autono-MaaS Vehicle
System Architecture is shown in
3. Application Interfaces
3.1. Typical Usage of APIs
In this section, Typical Usage of APIs is described.
A typical workflow of APIs is as follows (
3.2. APIs for vehicle motion control
In this section, the APIs for vehicle motion control are described.
3.2.1. API List for Vehicle Motion Control
3.2.1.1. Inputs
3.2.1.2. Outputs
3.2.2. Details of Each API for Vehicle Motion Control
3.2.2.1. Propulsion Direction Command
Request for shift change from/to forward (D range) to/from back (R range)
Values
Remarks
3.2.2.2. Immobilization Command
Request for turning on/off WheelLock
Values
The following table shows a case where EPB and Shift P are used for immobilization.
Remarks
3.2.2.3. Standstill Command
Request for applying/releasing brake holding function
Values
Remarks
3.2.2.4. Acceleration Command
Request for acceleration
Values
Estimated maximum deceleration to Estimated maximum acceleration [m/s2]
Remarks
3.2.2.5. Front Wheel Steer Angle Command
Values
Remarks
3.2.2.6. Vehicle Mode Command
Request for changing from/to manual mode to/from Autonomous Mode
Values
Remarks
N/A
3.2.2.7. High Dynamics Command
If ADK would like to increase braking response performance* of VP, High Dynamics Command should be set to “High”.
*Reaction time in VP upon a request from ADK
Values
Remarks
N/A
3.2.2.8. Propulsion Direction Status
Current shift Status
Remarks
3.2.2.9. Immobilization Status
Each immobilization system status
Values
The following table shows a case where EPB and Shift P are used for immobilization.
Remarks
3.2.2.10. Standstill Status
Status of Standstill
Remarks
3.2.2.11. Estimated Gliding Acceleration
Acceleration calculated in VP in case that throttle is closed, considering slope, road load and etc.
Values
[unit: m/s2]
Remarks
3.2.2.12. Estimated Maximum Acceleration
Acceleration calculated in VP in case that throttle is fully open, considering slope, road load and etc.
Values
[unit: m/s2]
Remarks
3.2.2.13. Estimated Maximum Deceleration
Maximum deceleration calculated in VP in case that brake in VP is requested as maximum, considering slope, road load and etc.
Values
[unit: m/s2]
Remarks
3.2.2.14. Front wheel steer angle
Values
Remarks
3.2.2.15. Front wheel steer angle rate
Front wheel steer angle rate
Values
Remarks
3.2.2.16. Front wheel steer angle rate limitation
The limit of the Front wheel steer angle rate
Values
[unit: rad/s]
Remarks
The limitation is calculated from the “vehicle speed—steering angle rate” map as shown in following Table 5 and
A) At a low speed or stopped situation, use fixed value (0.751 [rad/s]).
B) At a higher speed, the steering angle rate is calculated from the vehicle speed using 3.432 m/s3.
3.2.2.17. Estimated maximum lateral acceleration
Values
[unit: m/s2] (fixed value: 3.432)
Remarks
3.2.2.18. Estimated maximum lateral acceleration rate
Values
[unit: m/s3] (fixed value: 3.432)
Remarks
3.2.2.19. Intervention of accelerator pedal
This signal shows whether the accelerator pedal is depressed by a driver (intervention).
Values
Remarks
3.2.2.20. Intervention of brake pedal
This signal shows whether the brake pedal is depressed by a driver (intervention).
Values
Remarks
3.2.2.21. Intervention of steering wheel
This signal shows whether the steering wheel is operated by a driver (intervention).
Values
Remarks
3.2.2.22. Intervention of shift lever
This signal shows whether the shift lever is controlled by a driver (intervention)
Values
Remarks
3.2.2.23. Wheel speed pulse (front left), Wheel speed pulse (front right), Wheel speed pulse (rear left), Wheel speed pulse (rear right)
Values
Remarks
3.2.2.24. Wheel rotation direction (front left), Wheel rotation direction (front right), Wheel rotation direction (Rear left), Wheel rotation direction (Rear right)
Values
Remarks
3.2.2.25. Traveling direction
Moving direction of vehicle
Values
Remarks
3.2.2.26. Vehicle velocity
Estimated longitudinal velocity of vehicle
Values
Remarks
3.2.2.27. Longitudinal acceleration
Estimated longitudinal acceleration of vehicle
Values
Remarks
3.2.2.28. Lateral acceleration
lateral acceleration of vehicle
Values
Remarks
3.2.2.29. Yaw rate
Sensor value of yaw rate
Values
Remarks
3.2.2.30. Slipping Detection
Detection of tire glide/spin/skid
Remarks
3.2.2.31. Vehicle mode state
Autonomous or manual mode
Values
Remarks
3.2.2.32. Readiness for autonomization
This signal shows whether a vehicle can change to Autonomous Mode or not
Remarks
3.2.2.33. Failure status of VP functions for Autonomous Mode
This signal is used to show whether VP functions have some failures mode when a vehicle works as Autonomous Mode.
Values
Remarks
3.2.2.34. PCS Alert Status
Values
Remarks
N/A
3.2.2.35. PCS Preparation Status
Prefill Status as the preparation of PCS Brake
Values
Remarks
3.2.2.36. PCS Brake/PCS Brake Hold Status
Values
Remarks
N/A
3.2.2.37. ADS/PCS arbitration status
Arbitration status
Remarks
3.3. APIs for BODY control
3.3.1. API List for BODY control
3.3.1.1. Inputs
3.3.1.2. Outputs
3.3.2. Details of Each API for BODY Control
3.3.2.1. Turnsignal command
Request to control turn-signal
Values
Remarks
3.3.2.2. Headlight command
Request to control headlight
Values
Remarks
3.3.2.3. Hazardlight command
Request to control hazardlight
Remarks
3.3.2.4. Horn pattern command
Request to choose a pattern of ON-time and OFF-time per cycle
Values
Remarks
N/A
3.3.2.5. Horn cycle command
Request to choose the number of ON and OFF cycles
Values
0 to 7 [−]
Remarks
N/A
3.3.2.6. Continuous horn command
Request to turn on/off horn
Values
Remarks
3.3.2.7. Front windshield wiper command Request to control front windshield wiper
Values
Remarks
3.3.2.8. Rear windshield wiper command
Request to control rear windshield wiper
Values
Remarks
3.3.2.9. HVAC (1st row) operation command Request to start/stop 1st row air conditioning control
Values
Remarks
3.3.2.10. HVAC (2nd row) operation command
Request to start/stop 2nd row air conditioning control
Values
Remarks
3.3.2.11. Target temperature (1st left) command
Request to set target temperature in front left area
Values
Remarks
3.3.2.12. Target temperature (1st right) command
Request to set target temperature in front right area
Values
Remarks
3.3.2.13. Target temperature (2nd left) command
Request to set target temperature in rear left area
Values
Remarks
Request to set target temperature in rear right area
Values
Remarks
3.3.2.15. HVAC fan (1st row) command
Request to set fan level of front AC
Values
Remarks
3.3.2.16. HVAC fan (2nd row) command
Request to set fan level of rear AC
Values
Remarks
3.3.2.17. Air outlet (1st row) command
Request to set 1st row air outlet mode
Values
Remarks
3.3.2.18. Air outlet (2nd row) command
Request to set 2nd row air outlet mode
Values
Remarks
3.3.2.19. Air recirculation command
Request to set air recirculation mode
Values
Remarks
3.3.2.20. AC mode command
Request to set AC mode
Values
Remarks
3.3.2.21. Turnsignal status
Values
Remarks
N/A
3.3.2.22. Headlight status
Values
Remarks
N/A
3.3.2.23. Hazardlight status
Values
Remarks
N/A
3.3.2.24. Horn status
Values
Remarks
In the case that 3.3.2.4 the Horn Pattern Command is active, the Horn status is “1” even if there are OFF periods in some patterns.
3.3.2.25. Front windshield wiper status
Values
Remarks
N/A
3.3.2.26. Rear windshield wiper status
Values
Remarks
N/A
3.3.2.27. HVAC (1st row) status
Values
Remarks
3.3.2.28. HVAC (2nd row) status
Values
Remarks
3.3.2.29. Target Temperature (1st left) status
Values
Remarks
3.3.2.30. Target Temperature (1st right) status
Values
Remarks
3.3.2.31. Target Temperature (2nd left) status
Values
Remarks
3.3.2.32. Target Temperature (2nd right) status
Values
Remarks
3.3.2.33. HVAC fan (1st row) status
Values
Remarks
3.3.2.34. HVAC fan (2nd row) status
Values
Remarks
3.3.2.35. Air outlet (1st row) status
Values
Remarks
3.3.2.36. Air outlet (2nd row) status
Values
Remarks
3.3.2.37. Air recirculation status
Values
Remarks
3.3.2.38. AC mode status
Values
Remarks
3.3.2.39. Seat occupancy (1st right) status
Values
Remarks
3.3.2.40. Seat belt (1st left) status
Values
Remarks
N/A
3.3.2.41. Seat belt (1st right) status
Values
Remarks
N/A
3.3.2.42. Seat belt (2nd left) status
Values
Remarks
3.3.2.43. Seat belt (2nd right) status
Values
Remarks
3.3.2.44. Seat belt (3rd left) status
Values
Remarks
3.3.2.45. Seat belt (3rd center) status
Values
Remarks
3.3.2.46. Seat belt (3rd right) status
Values
Remarks
3.4. APIs for Power control
3.4.1. API List for Power control
3.4.1.1. Inputs
3.4.1.2. Outputs
3.4.2. Details of each API for Power control 3.4.2.1. Power mode command
Request to control power mode
Values
Remarks
[Sleep]
Vehicle power off condition. In this mode, the main battery does not supply power to each system, and neither VCIB nor other VP ECUs are activated.
[Wake]
VCIB is awake by the auxiliary battery. In this mode, ECUs other than VCIB are not awake except for some of the body electrical ECUs.
[Driving Mode]
Vehicle power on condition. In this mode, the main battery supplies power to the whole VP and all the VP ECUs including VCIB are awake.
3.4.2.2. Power mode status
Values
Remarks
3.5. APIs for Failure Notification
3.5.1. API List for Failure Notification
3.5.1.1. Inputs
3.5.1.2. Outputs
3.5.2. Details of each API for Failure Notification
3.5.2.1. Request for ADS Operation
Values
Remarks
3.5.2.2. Impact detection signal
Values
Remarks
Priority: crash detection>normal
Transmission interval is 100 ms within fuel cutoff motion delay allowance time (1 s) so that data can be transmitted more than 5 times.
In this case, an instantaneous power interruption is taken into account.
3.5.2.3. Performance deterioration of brake system
Values
Remarks
3.5.2.4. Performance deterioration of propulsion system
Values
Remarks
3.5.2.5. Performance deterioration of shift control system
Values
Remarks
3.5.2.6. Performance deterioration of immobilization system
Values
Remarks
3.5.2.7. Performance deterioration of Steering system
Values
Remarks
3.5.2.8. Performance deterioration of power supply system
Values
Remarks
3.5.2.9. Performance deterioration of communication system
Values
Remarks
3.6. APIs for Security
3.6.1. API List for Security
3.6.1.1. Inputs
3.6.1.2. Outputs
3.6.2. Details of Each API for Security
3.6.2.1. Door Lock (front) command, Door Lock (rear) command
Values
Remarks
(The functionality for individual locking is not supported in Toyota VP.)
3.6.2.2. Central door lock command
Request to control all doors' lock
Values
Remarks
3.6.2.3. Device Authentication Signature the 1st word, Device Authentication Signature the 2nd word, Device Authentication Signature the 3rd word, Device Authentication Signature the 4th word, Device Authentication Seed the 1st word, Device Authentication Seed the 2nd word
Device Authentication Signature the 1st word is presented in from 1st to 8th bytes of the signature.
Device Authentication Signature the 2nd word is presented in from 9th to 16th bytes of the signature.
Device Authentication Signature the 3rd word is presented in from 17th to 24th bytes of the signature.
Device Authentication Signature the 4th word is presented in from 25th to 32nd bytes of the signature.
Device Authentication Seed the 1st word is presented in from 1st to 8th bytes of the seed.
Device Authentication Seed the 2nd word is presented in from 9th to 16th bytes of the seed.
3.6.2.4. Door lock (1st left) status
Values
Remarks
3.6.2.5. Door lock (1st right) status
Values
Remarks
3.6.2.6. Door lock (2nd left) status
Values
Remarks
3.6.2.7. Door lock (2nd right) status
Values
Remarks
3.6.2.8. Door lock status of all doors
Values
Remarks
3.6.2.9. Alarm system status
Values
Remarks
N/A
3.6.2.9.1. Trip Counter
This counter is incremented in a unit of trips by the Freshness Value management master ECU.
Values
0—FFFFh
Remarks
3.6.2.9.2. Reset Counter
This counter is incremented periodically by the Freshness Value management master ECU.
Values
0—FFFFFh
Remarks
3.6.2.10. 1st Left Door Open Status
Status of the current 1st-left door open/close of the vehicle platform
Values
Remarks
N/A
3.6.2.11. 1st Right Door Open Status
Status of the current 1st-right door open/close
Values
Remarks
N/A
3.6.2.12. 2nd Left Door Open Status
Status of the current 2nd-left door open/close
Values
Remarks
N/A
3.6.2.13. 2nd Right Door Open Status
Status of the current 2nd-right door open/close
Values
Remarks
N/A
3.6.2.14. Trunk Status
Status of the current trunk door open/close
Values
Remarks
N/A
3.6.2.15. Hood Open Status
Status of the current hood open/close
Values
Remarks
N/A
4. API Guides to control Toyota Vehicles
This section shows in detail the way of using APIs for Toyota vehicles.
4.1. APIs for Vehicle Motion Control
4.1.1. API List for Vehicle Motion Control
Input and output APIs for vehicle motion control are shown in Table 14 and Table 15, respectively. Usage guides of some APIs are presented in the following sections as indicated in each table.
4.1.1.1. Inputs
4.1.1.2. Outputs
4.1.2. API guides in Details for Vehicle Motion Control
4.1.2.1. Propulsion Direction Command
Please refer to 3.2.2.1 for value and remarks in detail.
First deceleration is requested by Acceleration Command and the vehicle is stopped. When Traveling direction is set to “standstill”, any shift position can be requested by Propulsion Direction Command. (In
Deceleration has to be requested by Acceleration Command until completing shift change.
After shift position is changed, acceleration/deceleration can be chosen based on Acceleration Command.
While Vehicle mode state=Autonomous Mode, driver's shift lever operation is not accepted.
4.1.2.2. Immobilization Command
Please refer to 3.2.2.2 for value and remarks in detail.
Deceleration is requested with Acceleration Command to make a vehicle stop. When Vehicle velocity goes to zero, Immobilization function is activated by Immobilization Command=“Applied”. Acceleration Command is set to Deceleration until Immobilization Status is set to “Applied”.
When deactivating Immobilization function, Immobilization Command=“Released” has to be requested and simultaneously Acceleration Command has to be set as deceleration until confirming Immobilization Status=“Released”.
After Immobilization function is deactivated, the vehicle can be accelerated/decelerated based on Acceleration Command.
4.1.2.3. Standstill Command
Please refer to 3.2.2.3 for value and remarks in detail.
In case where Standstill Command is set as “Applied”, brakehold function can be ready to be used and brakehold function is activated in a condition where a vehicle stops and Acceleration Command is set as Deceleration (<0). And then Standstill Status is changed to “Applied”. On the other hand, in case where Standstill Command is set as “Released”, brakehold function is deactivated.
To make a vehicle stop, deceleration is requested with Acceleration Command.
When the vehicle stops for a while, Traveling direction is changed to “standstill”. Even during Standstill status=“Applied”, deceleration shall be requested with Acceleration Command.
If you want the vehicle to move forward, Acceleration Command is set as Acceleration (>0). Then brake hold function is released and the vehicle is accelerated.
4.1.2.4. Acceleration Command
Please refer to 3.2.2.4 for value and remarks in detail.
The below shows how a vehicle behaves when an acceleration pedal is operated.
In case where the accelerator pedal is operated, a maximum acceleration value of either 1) one calculated from accelerator pedal stroke or 2) Acceleration Command input from ADK is chosen. ADK can see which value is selected by checking Intervention of accelerator pedal.
The below shows how a vehicle behaves when a brake pedal is operated.
Deceleration value in the vehicle is the sum of 1) one calculated from the brake pedal stroke and 2) one requested from ADK.
4.1.2.5. Front Wheel Steer Angle Command
Please refer to 3.2.2.5 for value and remarks in detail.
The below shows the way of using Front Wheel Steer Angle Command.
Front Wheel Steer Angle Command is set as a relative value from Front wheel steer angle.
For example, in case where Front wheel steer angle=0.1 [rad] and a vehicle goes straight;
If ADK would like to go straight, Front Wheel Steer Angle Command should be set to 0+0.1=0.1[rad].
If ADK requests to steer by −0.3 [rad], Front Wheel Steer Angle Command should be set to −0.3+0.1=−0.2 [rad].
The below shows how a vehicle behaves when a driver operates the steering.
A maximum value is selected either from 1) one calculated from steering wheel operation by the driver or 2) one requested by ADK.
Note that Front Wheel Steer Angle Command is not accepted if the driver strongly operates the steering wheel. This situation can be found by Intervention of steering wheel flag.
4.1.2.6. Vehicle Mode Command
The state machine of mode transition for Autono-MaaS vehicle is shown in
The explanation of each state is shown as follows.
The explanation of each transition is shown as follows.
4.2. APIs for BODY Control
4.2.1. API List for BODY Control
4.2.1.1. Inputs
4.2.1.2. Outputs
4.3. APIs for Power Control
4.3.1. API List for Power Control
4.3.1.1. Inputs
4.3.1.2. Outputs
4.4. APIs for Failure Notification
4.4.1. API List for Failure Notification
4.4.1.1. Inputs
4.4.1.2. Outputs
4.5. APIs for Security
4.5.1. API List for Security
Input and output APIs for Security are shown in Table 22 and Table 23, respectively. Usage guides of some APIs are presented in the following sections as indicated in each table.
4.5.1.1. Inputs
4.5.1.2. Outputs
4.5.2. API guides in Details for Security
4.5.2.1. Device Authentication Protocol
Device authentication is applied when the VCIB is activated from “Sleep” mode.
After the authentication succeeds, the VCIB can start to communicate with ADK.
Authentication process is as shown in
Authentication Specification
Though an embodiment of the present disclosure has been described, it should be understood that the embodiment disclosed herein is illustrative and non-restrictive in every respect. The scope of the present disclosure is defined by the terms of the claims and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-157625 | Sep 2021 | JP | national |
