Vehicle control unit

Abstract

Control unit of a vehicle (10) comprising: a vehicle-specific sensor (61) configured to output a wave in front of a vehicle (10) and to detect a reflected wave of the output wave; a vehicle-to-own sensor device (60) configured to detect a vehicle traveling in front of the vehicle (10) as a vehicle ahead based on the reflected wave detected by the vehicle-to-own sensor (61), and to obtain an intermediate vehicle distance (D) between the vehicle (10) and the vehicle ahead based on the reflected wave; a wireless communication device (80, 81) configured to receive communicating vehicle ahead information, including communicating vehicle ahead acceleration information (Gs, Gas) about the acceleration of a communicating vehicle ahead (11), wherein the communicating vehicle ahead (11) is the vehicle ahead that has a wireless communication function; and an acceleration / deceleration control device (20, 30, 40) configured to control the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to a demand acceleration (Gj) of the own vehicle (10); the acceleration / deceleration control device (20, 30, 40) comprises: a first computation device configured to calculate a control request acceleration (CRE) based on the inter-vehicle distance (D) and a target inter-vehicle distance (Dtgt), wherein the control request acceleration (CRE) is an acceleration requested at the own vehicle (10) to maintain the inter-vehicle distance (D) at the target inter-vehicle distance (Dtgt); a second computing device configured to calculate a forward control request acceleration (GFF) based on the communicating vehicle ahead acceleration information (Gs, Gas), wherein the forward control request acceleration (GFF) is an acceleration requested from the own vehicle (10) to cause the own vehicle (10) to follow the communicating vehicle ahead (11); and a third calculating device configured to calculate the request acceleration (Gj) of the own vehicle (10) based on the control and feedforward request accelerations (GFB and GFF), wherein the acceleration / deceleration control device (20, 30, 40) is configured to perform a following driving control to cause the own vehicle (10) to follow the communicating preceding vehicle (11) by controlling the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to the requested acceleration (Gj) calculated by the third calculating device, characterized by the fact that the third computing unit is configured, to set the pre-control request acceleration (PCE) to zero if the vehicle's own sensor device (60) has not detected the vehicle ahead and the pre-control request acceleration (PCE) is greater than zero after an execution of the follow-up control has been started, and to adjust the feedforward acceleration (GFF) to the calculated feedforward acceleration (GFF) if the vehicle's own sensor device (60) has not detected the vehicle ahead and the feedforward acceleration (GFF) is less than zero after the execution of the follow-up driving control has been started.

Description

BACKGROUND OF THE INVENTION Technical field

[0001] The present invention relates to a control device of a vehicle for causing its own vehicle to follow a preceding vehicle by using information about the preceding vehicle received through wireless communication. Description of the related prior art

[0002] JP 2015-51716A describes a vehicle control device for controlling the acceleration of its own vehicle in order to cause the vehicle to follow a vehicle ahead, based on information about the acceleration of the vehicle ahead received through wireless communication. This control device is referred to below as "the conventional device".

[0003] The conventional device includes a vehicle-in-ground sensor, such as a millimeter-wave radar. The vehicle-in-ground sensor emits an output wave in front of the vehicle. If a vehicle ahead is present, the vehicle-in-ground sensor receives a wave reflected by the vehicle ahead. The conventional device obtains a distance between the vehicle and the vehicle ahead (hereinafter referred to as "the inter-vehicle distance") based on the wave reflected by the vehicle ahead and received by the vehicle-in-ground sensor. Furthermore, the conventional device obtains a speed of the vehicle (hereinafter referred to as "the vehicle speed").In addition, the conventional device obtains ahead-vehicle acceleration information about the acceleration of the ahead vehicle from the ahead vehicle via wireless communication.

[0004] The conventional device obtains an inter-vehicle time (or vehicle-to-vehicle time) by dividing the obtained inter-vehicle distance by the obtained own vehicle speed. It then calculates a control request acceleration, which is an acceleration of the own vehicle requested to cause the inter-vehicle time to match a target inter-vehicle time, based on the difference between the actual inter-vehicle time and the target inter-vehicle time. Furthermore, the conventional device calculates a feedforward request acceleration, which is an acceleration of the own vehicle requested to cause it to follow the vehicle ahead, based on the obtained acceleration information of the vehicle ahead.

[0005] Finally, the conventional device sets a total value of the control request acceleration and the feedforward request acceleration as a request acceleration of its own vehicle and accelerates or decelerates its own vehicle to achieve the request acceleration.

[0006] The German patent application DE 11 2011 102 666 T5 describes a vehicle control system. This system acquires vehicle-to-vehicle communication information from a vehicle traveling ahead of the vehicle in front of it. Based on this vehicle-to-vehicle communication information, a following control is executed to cause the vehicle to follow the vehicle ahead. During the following control, a parameter used in the following control is determined based on the state in which the vehicle-to-vehicle communication information is acquired.

[0007] The publication EP 3 041 723 B1 describes a vehicle driving control device comprising a sensor that receives information about a vehicle ahead, representing the status of a first vehicle ahead; a communication device that receives information about the acceleration / deceleration of the vehicle ahead, generated in a second vehicle ahead, via communication with the second vehicle ahead; and a control device that sets a first setpoint, based on the information about the vehicle ahead, and a second setpoint, based on the setpoint acceleration / deceleration of the host vehicle.The control unit generates the first and second setpoints based on information about the acceleration / deceleration of the vehicle ahead and controls the acceleration / deceleration of the host vehicle based on these generated setpoints. The control unit corrects the acceleration / deceleration information of the vehicle ahead according to an index value to generate the second setpoint, where the index value represents an identity between the first and second vehicles ahead.

[0008] The document DE 10 2009 021 476 A1 describes a method for the automatic longitudinal guidance of a motor vehicle, which includes an adaptive longitudinal guidance system (ACC system), wherein a control device of the longitudinal guidance system receives information concerning the distances to several vehicles ahead, the respective speeds of these vehicles and the respective acceleration of these vehicles, and the longitudinal guidance of the motor vehicle is carried out depending on the received information.

[0009] The document DE 199 63 224 A1 describes a method for regulating the speed of a motor vehicle and the distance of the motor vehicle to at least one preceding motor vehicle, in which a safety time defining the safety distance to the preceding motor vehicle is set within a predetermined limit, in which the speed of the motor vehicle and the distance to the preceding motor vehicle are determined with the aid of a detection device, in which the safety distance is calculated from the speed of the motor vehicle and the safety time, and in the event of a deviation of the detected distance from the safety distance, the motor vehicle is braked or accelerated.During a loss of the vehicle ahead from the detection range of the detection device, the speed driven at the time before the loss is maintained until a predetermined delay time has elapsed or until a vehicle ahead is again detected by the detection device as the control object. SUMMARY OF THE INVENTION

[0010] If a guardrail is provided on the side of the road where the vehicle is traveling, the vehicle's sensor receives the wave reflected by the guardrail. In this case, the vehicle's sensor simultaneously receives both the wave reflected by the vehicle ahead and the wave reflected by the guardrail. Therefore, a situation in which the vehicle cannot detect the vehicle ahead can occur temporarily, even if the vehicle ahead is using the reflected wave received by the vehicle's sensor. Furthermore, even if the vehicle ahead is present, the vehicle's inability to detect it can occur for various reasons other than the one described above.

[0011] Additionally, if a vehicle ahead is present and the conventional device's own vehicle sensor cannot detect it, the ahead vehicle continues to transmit its acceleration information to the own vehicle. Consequently, the conventional device can calculate the feedforward acceleration request based on the acceleration information sent by the ahead vehicle. In many cases, the occurrence of the condition where the own vehicle sensor cannot detect the vehicle ahead is temporary, and it is therefore likely that the own vehicle sensor will restart detection of the vehicle ahead.In this case, continuing the acceleration control, which is executed in the vehicle itself based on the calculated pre-control acceleration request, is advantageous for ensuring a smooth restart of the vehicle's journey following the vehicle ahead, even under the temporary condition that the vehicle's sensor cannot detect the vehicle ahead. In this regard, the pre-control acceleration request calculated in the state where the vehicle's sensor cannot detect the vehicle ahead can be a positive value (i.e., a value indicating a request for acceleration from the vehicle itself). In this case, the vehicle will accelerate.For example, if a vehicle without wireless communication capabilities is present between the vehicle and the vehicle transmitting its acceleration information, an excessive reduction in the inter-vehicle distance may occur. Furthermore, if the vehicle's sensor fails to detect a vehicle with wireless communication capabilities, and thus the conventional device does not identify the vehicle as the vehicle ahead, an excessive reduction in the inter-vehicle distance may occur.

[0012] The present invention was conceived to solve the problem described above. One object of the present invention is to provide a vehicle control device that can cause the vehicle to follow the vehicle ahead precisely, while preventing an excessive reduction in the distance between the vehicle and the vehicle ahead, even when the vehicle's sensor has not detected the vehicle ahead.

[0013] This problem is solved by a vehicle control device according to claim 1. Advantageous embodiments are specified in the dependent claims.

[0014] The vehicle's control unit, according to one configuration, comprises: a vehicle-specific sensor (61) configured to output a wave in front of a vehicle (10) and to detect a reflected wave of the output wave; a vehicle-in-situ sensor device (60) configured to detect a vehicle traveling in front of the vehicle (10) as a vehicle ahead based on the reflected wave detected by the vehicle-in-situ sensor (61), and to obtain an intermediate vehicle distance (D) between the vehicle (10) and the vehicle ahead based on the reflected wave; a wireless communication device (80, 81) configured to receive communicating vehicle ahead information, including communicating vehicle ahead acceleration information (Gs, Gas) about the acceleration of a communicating vehicle ahead (11), wherein the communicating vehicle ahead (11) is the vehicle ahead that has a wireless communication function; and an acceleration / deceleration control device (20, 30, 40) configured to control the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to a demand acceleration (Gj) of the own vehicle (10).

[0015] The acceleration / deceleration control device (20, 30, 40) comprises first to third computation units. The first computation unit is configured to calculate a feedback request acceleration or control request acceleration (GFB) based on the intervehicle distance (D) and a target intervehicle distance (Dtgt) (see step 265 according to Fig. 2 and a routine according to Fig. 5) The control request acceleration (GFB) is an acceleration requested for the own vehicle (10) to maintain the inter-vehicle distance (D) at the target inter-vehicle distance (Dtgt).

[0016] The second calculation unit is configured to calculate a feedforward acceleration (GFF) based on the communicating vehicle ahead information (Gs, Gas) (see step 260 according to Fig. 2 and a routine according to Fig. 4) The advance control request acceleration (ACA) is an acceleration that is requested from the own vehicle (10) to cause the own vehicle (10) to follow the communicating preceding vehicle (11).

[0017] The third calculation unit is configured to calculate the request acceleration (Gj) of the own vehicle (10) based on the feedforward and control request accelerations (GFB and GFF) (see step 270 according to Fig. 2).

[0018] The acceleration / deceleration control device (20, 30, 40) is configured to perform follow-vehicle control to cause the own vehicle (10) to follow the communicating preceding vehicle (11) by controlling the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to the requested acceleration (Gj) calculated by the third computation device (see step 275 according to Fig. 2).

[0019] According to the following driving control, the own vehicle is caused to follow the communicating vehicle ahead at an acceleration that is set based on the acceleration of the communicating vehicle ahead, while the intermediate vehicle distance is maintained at a predetermined distance (i.e. the target intermediate vehicle distance).

[0020] Additionally, the third calculation unit is configured to set the feedforward request acceleration (GFF) to zero (see step 440 according to Fig. 4) if the vehicle's own sensor device (60) has not detected the vehicle ahead (see the determination of 'No' in step 451 according to Fig. 4) and the feedforward request acceleration (FRA) is greater than 0 (see a determination of “Yes” in step 435 according to Fig. 4) after an execution of the follow-up driving control has been started. In addition, the advance control request acceleration (GFF) is set to the calculated advance control request acceleration (GFF) if the vehicle's own sensor device (60) has not detected the vehicle ahead and the advance control request acceleration (GFF) is less than zero after the execution of the follow-up driving control has been started.

[0021] The Communicating Ahead Vehicle acceleration information (Gs, Gas) may include information about a request acceleration (Gs) of the communicating ahead vehicle (11) calculated by the communicating ahead vehicle (11) on the basis of actuation variables (Accp, Brkp) of an acceleration actuator or accelerator operator or a brake actuator or brake operator of the communicating ahead vehicle (11).

[0022] Furthermore, the Communicating Ahead Vehicle Acceleration Information (Gs, Gas) can be calculated by a control unit of the Communicating Ahead Vehicle (11) based on information about the acceleration of a vehicle traveling in front of the Communicating Ahead Vehicle (11) obtained by a wireless communication device of the Communicating Ahead Vehicle (11) from the vehicle traveling in front of the Communicating Ahead Vehicle (11), if the control unit of the Communicating Ahead Vehicle (11) performs the same control as the following vehicle control to cause the Communicating Ahead Vehicle (11) to travel in follow of the vehicle traveling in front of the Communicating Ahead Vehicle (11).

[0023] This means that if the vehicle's own sensor has not detected the vehicle ahead and the feedforward acceleration is greater than 0, the feedforward acceleration is set to 0. That is, the feedforward acceleration is limited to a value less than or equal to 0. Thus, the feedforward acceleration is less than or equal to 0. Consequently, the acceleration of the vehicle derived from the feedforward acceleration is prevented. As a result, an excessive reduction in the distance between the vehicle and the vehicle ahead is prevented.

[0024] The acceleration / deceleration control device (20, 30, 40) can be configured to stop own vehicle acceleration control (10) that uses the communicating vehicle ahead acceleration information (Gs, Gas) when an elapsed time is greater than or equal to a predetermined time, where the elapsed time is the time that has elapsed since the own vehicle sensor (61) failed to detect the vehicle ahead after the execution of the following vehicle control has been initiated. As described above, in many cases the own vehicle sensor device is temporarily unable to detect the vehicle ahead. Consequently, when the elapsed time is greater than or equal to the predetermined time, a vehicle that can be identified as the vehicle ahead may not be present, for example, due to a lane change by the vehicle ahead.

[0025] If the vehicle ahead is not present, the communicating vehicle ahead acceleration information obtained through the vehicle's wireless communication device no longer provides information about the acceleration of the vehicle ahead. In this case, the vehicle's acceleration control, which uses the communicating vehicle ahead acceleration information, is preferably stopped. This prevents the execution of the vehicle's acceleration control, which uses information about the acceleration of a vehicle other than the one ahead, by stopping the vehicle's acceleration control that uses the communicating vehicle ahead acceleration information when the elapsed time is greater than or equal to the predetermined time.

[0026] In the foregoing description, for the sake of clarity, elements of the present invention that correspond to elements of an embodiment described below are designated by reference numerals, which are used in conjunction with parentheses in the description of the embodiment. However, the elements of the present invention are not limited to those elements of the embodiment defined by the reference numerals. The other problems, features, and consequent advantages of the present invention can be readily understood from the description of the embodiment of the present invention together with the drawing. BRIEF DESCRIPTION OF THE DRAWING Fig. Figure 1 shows a general configuration representation to illustrate a control unit of a vehicle according to an embodiment of the present invention and the vehicle in which the control unit is installed. Fig. Figure 2 shows a diagram illustrating a flowchart of a routine executed by a CPU of a vehicle control ECU located in Fig. 1 is shown. Fig. Figure 3 shows a diagram to illustrate a flowchart of a routine executed by the CPU. Fig. Figure 4 shows a diagram to illustrate a flowchart of a routine executed by the CPU. Fig. Figure 5 shows a diagram to illustrate a flowchart of a routine executed by the CPU. Fig. Figure 6(A) shows a representation to illustrate a lookup table used to obtain a second correction coefficient for acceleration based on an intermediate vehicle time. Fig. Figure 6(B) shows a representation to illustrate a lookup table used to obtain a second correction coefficient for a delay based on the intermediate vehicle time. Fig. Figure 6(C) shows a representation to illustrate a lookup table used to obtain a third correction coefficient for acceleration based on the speed of one's own vehicle. Fig. Figure 6(D) shows a representation to illustrate a lookup table used to obtain a third correction coefficient for deceleration based on the speed of the vehicle itself. DESCRIPTION OF PREFERRED EXECUTION EXAMPLES

[0027] A vehicle control unit according to an embodiment of the present invention is described below with reference to the drawing. Hereinafter, the control unit according to the embodiment is referred to as "the embodiment control unit". In the description, the drawing, and the claims, a "own vehicle" is a vehicle to which the present invention is applied, and a "leading vehicle" is a vehicle traveling in front of the own vehicle, detected by a sensor installed in the own vehicle as described below, and outputting information that can be used by the control unit of the own vehicle to modify a control mechanism to cause the own vehicle to move.

[0028] As it is in Fig. As shown in Figure 1, the exemplary embodiment control unit is used in a vehicle (a self-contained vehicle) 10. The self-contained vehicle 10 comprises a vehicle control ECU 20, a power engine control ECU 30, an accelerator pedal actuation size sensor 31, a brake control ECU 40, a brake pedal actuation size sensor 41, vehicle wheel speed sensors 42a to 42d, a steering control ECU 50, a sensor ECU 60, a self-contained vehicle sensor 61, a GPS device 70, a wireless communication control ECU 80, and a wireless antenna 81. A preceding vehicle 11 has the same configuration as the configuration of the self-contained vehicle 10.

[0029] The vehicle control ECU 20 can send and receive data to / from, i.e., communicate with, the power engine control ECU 30, the brake control ECU 40, the steering control ECU 50, the sensor ECU 60, the GPS device 70, and the wireless communication control ECU 80 via a communication / sensor system CAN (i.e., a communication / sensor system control area network) 101. Each of the ECUs is an electronic control unit and includes as a main component a microcomputer comprising a CPU, ROM, RAM, interface, and the like. The CPU is configured or programmed to execute instructions (or programs) stored in memory (i.e., the ROM) to perform various functions, which are described below.

[0030] The vehicle control ECU 20 is electrically connected to a cooperative following driving control request switch 21, which is an on / off switch, and various sensors 22. Hereinafter, the cooperative following driving control request switch 21 is referred to as "the CACC switch 21". When the CACC switch 21 is set to an on position by an occupant (in particular the driver) of their own vehicle 10, a request is made to the vehicle control ECU 20 to initiate an execution of a cooperative following driving control operation, as described below. The cooperative following driving control includes an inter-vehicle distance control operation, which is described below.

[0031] The engine control ECU 30 is known and is configured or programmed to receive detection signals from sensors (not shown) configured to detect various parameters of the operating states of an internal combustion engine (not shown). In particular, the engine control ECU 30 is electrically connected to the accelerator pedal actuation parameter sensor 31.

[0032] The accelerator pedal actuation quantity sensor 31 detects an actuation quantity Accp of an accelerator pedal 91 as an acceleration operator (hereinafter referred to as "the accelerator pedal actuation quantity Accp") and outputs a detection signal expressing the accelerator pedal actuation quantity Accp to the engine control ECU 30. The engine control ECU 30 is configured or programmed to obtain the accelerator pedal actuation quantity Accp based on the detection signal, to calculate or obtain a request acceleration Gj based on the obtained accelerator pedal actuation quantity Accp, and to store the calculated request acceleration Gj in the RAM of the engine control ECU 30.It should be noted that the engine control ECU 30 may be configured or programmed to calculate the requested acceleration Gj based on a self-propelled vehicle speed SPDj 10, obtained as described below, and an engine speed NE. Hereinafter, the self-propelled vehicle speed SPDj is referred to as "the self-propelled vehicle speed SPDj".

[0033] Furthermore, engine actuation devices 32, which include a (not shown) throttle valve actuation device, are electrically connected to the engine control ECU 30. The engine control ECU 30 is configured or programmed to activate the engine actuation devices 32 to modify a torque generated by the (not shown) engine of the own vehicle 10 such that the acceleration of the own vehicle 10 approaches the requested acceleration Gj when the requested acceleration Gj of the own vehicle 10 is a positive value, i.e., when it is requested that the own vehicle 10 accelerate.

[0034] The brake control ECU 40 is known and is configured or programmed to receive detection signals from (not shown) sensors configured to detect various quantities of operating states of the vehicle 10 (hereinafter referred to as "the vehicle operating state quantities"). In particular, the brake control ECU 40 is electrically connected to the brake pedal actuation quantity sensor 41 and the vehicle wheel speed sensors 42a to 42d.

[0035] The brake pedal actuation sensor 41 detects an actuation value Brkp of a brake pedal 93 as a brake operator and outputs a detection signal expressing the actuation value Brkp to the brake control ECU 40. Hereinafter, the actuation value Brkp is referred to as "the brake pedal actuation value Brkp". The brake control ECU 40 is configured or programmed to obtain the brake pedal actuation value Brkp based on the detection signal sent by the brake pedal actuation sensor 41, to calculate or obtain the requested acceleration Gj, including the requested deceleration, based on the obtained brake pedal actuation value Brkp, and to store the calculated requested acceleration Gj in the RAM of the brake control ECU 40.It should be noted that the brake control ECU 40 may be configured or programmed to calculate the requested acceleration Gj based on the vehicle's own speed SPDj, which is obtained as described below.

[0036] The vehicle wheel speed sensors 42a to 42d are provided at the respective vehicle wheels of the vehicle 10. The vehicle wheel speed sensors 42a to 42d each detect the vehicle wheel speeds ωa to ωd and output detection signals, which express the vehicle wheel speeds ωa to ωd, to the brake control ECU 40.

[0037] The brake control ECU 40 is configured or programmed to obtain the vehicle wheel speeds ωa to ωd based on the acquisition signals and to store the obtained vehicle wheel speeds ωa to ωd in the RAM of the brake control ECU 40.

[0038] Furthermore, the brake control ECU 40 is configured or programmed to calculate an average value wave of the obtained vehicle wheel speeds ωa to ωd (wave = (ωa + ωb + ωc + ωd) / 4) and to store the calculated average value wave as the vehicle speed SPDj of the vehicle 10 in the RAM of the brake control ECU 40. Hereinafter, the average value wave is referred to as "the average vehicle wheel speed wave".

[0039] Alternatively, the brake control ECU 40 can be configured or programmed to obtain the own vehicle speed SPDj based on a detection signal output by a (not shown) sensor configured to detect a rotational speed of a drive shaft of the own vehicle 10, rather than obtaining the average vehicle wheel speed wave as the own vehicle speed SPDj.

[0040] Furthermore, the brake control ECU 40 is configured or programmed to calculate the magnitude of a change in the achieved vehicle speed SPDj per small unit of time, i.e., to calculate a time-derived value of the vehicle speed SPDj as an actual acceleration Gaj (= dSPDj / dt) and to store the calculated actual acceleration Gaj in the RAM of the brake control ECU 40.

[0041] Furthermore, a brake actuation device 43 of a friction brake device or the like is electrically connected to the brake control ECU 40. The brake control ECU 40 is configured or programmed to activate the brake actuation device 43 to generate friction braking forces at the vehicle wheels of the own vehicle 10, such that the deceleration of the own vehicle 10 approaches the requested deceleration Gj according to the requested deceleration when the requested deceleration Gj of the own vehicle 10 is a negative value, i.e., when the deceleration of the own vehicle 10 is requested.

[0042] The vehicle control ECU 20, the engine control ECU 30, and the brake control ECU 40 accelerate or decelerate the vehicle 10 cooperatively. Consequently, these ECUs 20, 30, and 40 together form an acceleration / deceleration control device for controlling the acceleration of the vehicle 10.

[0043] The steering control ECU 50 is known and configured or programmed to receive detection signals from sensors (not shown) configured to detect various vehicle operating conditions. Furthermore, a steering actuation device 53, such as a motor of an electric power steering device (not shown), is electrically connected to the steering control ECU 50.

[0044] The sensor ECU 60 is electrically connected to the vehicle sensor 61. The vehicle sensor 61 is a known millimeter-wave radar sensor. The vehicle sensor 61 emits a millimeter wave (an output wave) in front of the vehicle 10. The millimeter wave is reflected by the vehicle 11 ahead. The vehicle sensor 61 receives this reflected millimeter wave.

[0045] The sensor ECU 60 is configured or programmed to detect the vehicle 11 ahead, which is traveling directly in front of the own vehicle 10, based on the reflected millimeter wave received by the own vehicle sensor 61. Furthermore, the sensor ECU 60 is configured or programmed to determine a difference dSPD between the own vehicle speed SPDj and a speed SPDs of the vehicle 11 ahead (i.e., a relative speed dSPD between the own vehicle 10 and the vehicle 11 ahead) (dSPD = SPDs - SPDj), an intermediate vehicle distance D between the own vehicle and the vehicle 11 ahead, and a relative orientation of the vehicle 11 ahead with respect to the own vehicle 10 in a chronological manner each time a predetermined time elapses, based on a phase difference between the millimeter wave output by the own vehicle sensor 61.and the reflected millimeter wave received by the vehicle's own sensor 61, an attenuation level of the reflected millimeter wave, a time until the reflected millimeter wave is received since the millimeter wave was emitted by the vehicle's own sensor 61, and the like. The sensor ECU 60 stores the obtained relative speed dSPD, the inter-vehicle distance D, the relative orientation, and the like in the RAM of the sensor ECU 60.

[0046] Consequently, the sensor ECU 60 forms a self-vehicle sensor device that detects or obtains the vehicle ahead 11 on the basis of the reflected millimeter wave detected by the self-vehicle sensor 61 and obtains the inter-vehicle distance D between the own vehicle 10 and the vehicle ahead 11 on the basis of the reflected millimeter wave detected by the self-vehicle sensor 61.

[0047] The GPS device 70 is known to obtain a latitude and longitude of a point where the own vehicle 10 is driving, based on a GPS signal sent by an artificial satellite, and stores the obtained latitude and longitude as a position of the own vehicle 10 in the RAM of the GPS device 70.

[0048] The wireless communication control ECU 80 is electrically connected to the wireless antenna 81, which is used to perform wireless inter-vehicle or vehicle-to-vehicle communication. The wireless communication control ECU 80 is configured or programmed to receive communication information or communicating vehicle information, including data that identifies the communicating vehicles. This data is transmitted by the communicating vehicles via wireless communication each time a predetermined time elapses, and the received data is stored in the RAM of the wireless communication control ECU 80. Each of the communicating vehicles is different from the host vehicle and has a function that performs wireless communication.The communicating vehicle information sent by each of the communicating vehicles includes data specifying the operating condition variables of each of the communicating vehicles.

[0049] The data specifying the operating state variables of each of the communicating vehicles, and received by the wireless communication control ECU 80 of the vehicle 10 through wireless inter-vehicle communication, include data obtained by the vehicle control ECU 20, the engine control ECU 30, the brake control ECU 40, and the like of each of the communicating vehicles based on acquisition signals output by various sensors of each of the communicating vehicles, data of states of the actuating devices of each of the communicating vehicles to which the vehicle control ECU 20, the engine control ECU 30, the brake control ECU 40, and the like of each of the communicating vehicles send activation signals, and the like.

[0050] In particular, the data sent by the communicating vehicle as communication data includes data (A) to (G) as described below. (A) A vehicle speed SPDc of the communicating vehicle obtained by the brake control ECU 40 of the communicating vehicle. Hereinafter, this vehicle speed SPDc is referred to as the ‘Communicating Vehicle Speed ​​SPDc’. (B) A position of the communicating vehicle obtained by the GPS device 70 of the communicating vehicle. (C) A request acceleration Gc of the communicating vehicle calculated by the engine control ECU 30 of the communicating vehicle on the basis of the accelerator pedal actuation quantity Accp of the communicating vehicle when no cooperative following control or CACC (cooperative adaptive cruise control) and inter-vehicle distance control or ACC (adaptive cruise control) is performed in the communicating vehicle. (D) A request acceleration Gc of the communicating vehicle corresponding to a requested deceleration of the communicating vehicle, calculated by the brake control ECU 40 of the communicating vehicle on the basis of the brake pedal actuation quantity Brkp of the communicating vehicle when any of the cooperation following driving control and the inter-vehicle distance control is not executed in the communicating vehicle. (E) A request acceleration Gc of the communicating vehicle, calculated by the vehicle control ECU 20 of the communicating vehicle on the basis of the request acceleration Gss of a vehicle immediately in front of the communicating vehicle, to cause the communicating vehicle to follow the vehicle immediately in front of the communicating vehicle when any of the cooperation following control and inter-vehicle distance control is executed in the communicating vehicle. (F) An actual acceleration Gac of the communicating vehicle obtained by the brake control ECU 40 of the communicating vehicle based on the average vehicle wheel speed wave of the communicating vehicle.

[0051] Furthermore, the wireless communication control ECU 80 is configured or programmed to send communication information (own vehicle information) which includes the data described above, specifying the operating condition variables of the own vehicle 10, to the outside of the own vehicle 10 each time a predetermined time elapses. <Summary of the cooperative following driving control system>

[0052] The following is a summary of the Cooperative Acceleration Control (CACC) performed by the exemplary control unit. The exemplary control unit initiates an execution of the Cooperative Acceleration Control when the CACC switch 21 is positioned in the ON position by the occupant, in particular the driver of their own vehicle 10. It should be noted that the vehicle control ECU 20 is configured or programmed to control the operation of the engine control devices 32 based on the accelerator pedal actuation value Accp, the engine speed NE, and the like when the CACC switch 21 is in the OFF position.Additionally, the brake control ECU 40 is configured or programmed to control the operation of the brake actuation device 43 based on the brake pedal actuation magnitude Brkp and the vehicle's own speed SPDj or the vehicle wheel speeds ωa to ωd when the CACC switch 21 is in the off position.

[0053] When the vehicle control ECU 20 starts the execution of the cooperative following driving control, the vehicle control ECU 20 starts an execution of a processing that identifies a communicating vehicle, which is detected or obtained by the own vehicle sensor 61 among the communicating vehicles, which sends data to the own vehicle 10, as a communicating ahead vehicle on the basis of data obtained by the own vehicle sensor 61 and the sensor ECU 60, and data obtained by the wireless antenna 81 and the wireless communication control ECU 80.

[0054] For example, the vehicle control ECU 20 estimates the speed of a candidate vehicle, which is a candidate of the communicating vehicle (identified as the communicating leading vehicle 11), based on the relative vehicle speed dSPD and the vehicle's own speed SPDj obtained by the sensor ECU 60. If there is a high degree of similarity between the estimated speed of the candidate vehicle and the speed of the candidate vehicle transmitted by the candidate vehicle via wireless communication, the vehicle control ECU 20 identifies this candidate vehicle as the communicating leading vehicle 11. For example, a method described in JP 5 522 193 B2 can be used as a method for identifying the communicating leading vehicle 11.

[0055] Furthermore, in this embodiment, a target value Ttgt is preset, derived from a value T obtained by dividing the distance between vehicles D by the vehicle's own speed SPDj (T = D / SPDj). Hereinafter, the value Ttgt is referred to as "the target inter-vehicle time Ttgt". The target inter-vehicle time Ttgt is set to a predetermined constant value. In this respect, the target inter-vehicle time Ttgt can be adjusted variably by a switch (not shown) operated by the driver of the vehicle 10. < Regulation >

[0056] The exemplary embodiment control unit controls the acceleration, including deceleration, of the own vehicle 10 such that a value T, obtained by dividing the actual intermediate vehicle distance D by the actual own vehicle speed SPDj, corresponds to the target intermediate vehicle time Ttgt when the CACC switch 21 is set to the ON position by the driver of the own vehicle 10. Hereinafter, the value T is referred to as "the intermediate vehicle time T".

[0057] For example, if the communicating vehicle 11 ahead accelerates under the condition that the inter-vehicle time T equals the target inter-vehicle time Ttgt and the own vehicle speed SPDj is constant, the inter-vehicle distance D increases. As a result, the inter-vehicle time T becomes greater than the target inter-vehicle time Ttgt, and thus the exemplary implementation control unit accelerates its own vehicle 10 to reduce the inter-vehicle time T.

[0058] In contrast, if the communicating vehicle 11 ahead decelerates under the condition that the intervehicle time T corresponds to the target intervehicle time Ttgt and the own vehicle speed SPDj is constant, the intervehicle distance D decreases. As a result, the intervehicle time T becomes less than the target intervehicle time Ttgt, whereby the exemplary implementation control unit decelerates its own vehicle 10 in order to increase the intervehicle time T.

[0059] When the exemplary control unit accelerates or decelerates the own vehicle 10, the exemplary control unit calculates or sets a requested acceleration Dj of the own vehicle 10, as described below, and controls the engine ECU 30 to cause the engine control ECU 30 to control the operation of the engine actuators 32 of the engine, or controls the brake control ECU 40 to cause the brake control ECU 40 to control the operation of the brake actuator 43 of the brake device, so that the requested acceleration Gj is achieved, that is, so that the acceleration of the own vehicle 10 corresponds to the requested acceleration Gj. The requested acceleration Gj can be one of a positive value for accelerating the own vehicle 10 and a negative value for decelerating the own vehicle 10.This allows the request acceleration Gj to be described as a requested acceleration / deceleration Gj.

[0060] The exemplary control unit multiplies the target inter-vehicle time Ttgt by the actual vehicle speed SPDj to calculate or obtain a target inter-vehicle distance Dtgt (= Ttgt x SPDj). In this exemplary embodiment, the target inter-vehicle time Ttgt is set to a constant value, so that the target inter-vehicle distance Dtgt increases when the actual vehicle speed SPDj increases.

[0061] Furthermore, the exemplary implementation control unit calculates or obtains a difference dD between the target inter-vehicle distance Dtgt and the actual inter-vehicle distance D (dD = D - Dtgt). Hereinafter, the difference dD is referred to as "the inter-vehicle distance difference dD". The calculated inter-vehicle distance difference dD is a positive value if the actual inter-vehicle distance D is greater than the target inter-vehicle distance Dtgt.

[0062] Additionally, the exemplary embodiment control unit obtains the relative vehicle speed dSPD, which is detected by the vehicle's own sensor 61. The obtained relative vehicle speed dSPD is a positive value if the vehicle speed SPDs of the communicating preceding vehicle 11 is greater than the vehicle's own vehicle speed SPDj. Hereinafter, the vehicle speed SPDs is referred to as "the preceding vehicle speed SPDs".

[0063] The exemplary control unit then calculates or obtains a combined value P (= dD x KFB1 + dSPD x KFB2) from a value obtained by multiplying the inter-vehicle distance difference dD by a correction coefficient KFB1 and a value obtained by multiplying the relative driving speed dSPD by a correction coefficient KFB2. The correction coefficients KFB1 and KFB2 are each set to positive constant values ​​greater than 0.

[0064] If the intended use calculation value P is a positive value, it can be determined that the acceleration of the own vehicle is required to keep the intermediate vehicle time T at the target intermediate vehicle time Ttgt or to steer it towards the target intermediate vehicle time Ttgt, that is, to keep the intermediate vehicle distance D at the target intermediate vehicle distance Dtgt or to steer it towards the target intermediate vehicle distance Dtgt.

[0065] In this case, the exemplary implementation control unit calculates or obtains a control request acceleration or feedback request acceleration GFB by multiplying the intended use calculation value P by a correction coefficient KFB3 (GFB = (dD x KFB1 + dSPD x KFB2) x KFB3). The correction coefficient KFB3 is a positive value greater than 0 and less than or equal to 1, decreasing as the vehicle speed SPDj increases. Consequently, if the vehicle acceleration 10 is required, the calculated control request acceleration GFB is a positive value.

[0066] In contrast, if the intended use calculation value P is a negative value, it can be determined that the deceleration of the own vehicle 10 is necessary to maintain the intermediate vehicle time T at the target intermediate vehicle time Ttgt or to control it towards the target intermediate vehicle time Ttgt, that is, to maintain the intermediate vehicle distance D at the target intermediate vehicle distance Dtgt or to control it towards the target intermediate vehicle distance Dtgt. In this case, the exemplary implementation control unit obtains the intended use calculation value P as the control requirement acceleration GFB (= dD x KFB1 + dSPD x KFB2). Consequently, if the deceleration of the own vehicle 10 is necessary, the obtained control requirement acceleration GFB is a negative value.

[0067] The exemplary implementation control unit can control the inter-vehicle time T to the target inter-vehicle time Ttgt by accelerating or decelerating its own vehicle 10 such that the control request acceleration GFB is achieved. In this regard, for example, the inter-vehicle distance D and the relative vehicle speed dSPD, obtained by the sensor ECU 60, vary after the communicating preceding vehicle 11 begins to accelerate or decelerate. Consequently, if the acceleration or deceleration of the own vehicle 10 is controlled solely using the control request acceleration GFB, the start time of the acceleration or deceleration of the own vehicle 10 is delayed relative to the start time of the acceleration or deceleration of the communicating preceding vehicle 11. < Feedforward control >

[0068] Accordingly, the embodiment control unit predicts the start of acceleration or deceleration of the communicating preceding vehicle 11 based on preceding vehicle acceleration information about the acceleration of the communicating preceding vehicle 11 obtained by the wireless communication control ECU 80, controlling the acceleration of its own vehicle 10 based on the result of the prediction.

[0069] In particular, the exemplary embodiment control unit calculates, estimates, or obtains the acceleration Ges of the communicating preceding vehicle 11 based on a value fh (Gs) obtained by filtering the requested acceleration Gs of the communicating preceding vehicle 11 with a high-pass filter, and a value hl (Gas) obtained by filtering the actual acceleration Gas of the communicating preceding vehicle 11 with a low-pass filter, when the requested acceleration Gs and the actual acceleration Gas of the communicating preceding vehicle 11 have been obtained by the wireless communication control ECU 80. Hereinafter, the estimated acceleration Ges of the communicating preceding vehicle 11 is referred to simply as "the estimated acceleration Ges".

[0070] Alternatively, the embodiment control unit obtains or estimates the actual acceleration gas of the communicating preceding vehicle 11 as the estimated acceleration Ges of the communicating preceding vehicle 11 if only the actual acceleration gas of the communicating preceding vehicle 11 is obtained by the wireless communication control ECU 80.

[0071] If the acceleration of the communicating vehicle ahead 11 is predicted, the calculated or obtained estimated acceleration Ges is a positive value. Conversely, if the deceleration of the communicating vehicle ahead 11 is predicted, the calculated or obtained estimated acceleration Ges is a negative value.

[0072] The exemplary embodiment control device calculates or obtains a value, obtained by multiplying the calculated or obtained estimated acceleration Ges by a coefficient less than 1, as a feedforward acceleration request value (GFF). If the acceleration of the communicating preceding vehicle 11 is predicted, the calculated feedforward acceleration request value (GFF) is a positive value. Conversely, if the deceleration of the communicating preceding vehicle 11 is predicted, the calculated feedforward acceleration request value (GFF) is a negative value.

[0073] The exemplary embodiment control unit calculates or obtains a final required acceleration Gj of the vehicle 10 by adding the feedforward required acceleration GFF to the control required acceleration GFB (Gj = GFF + GFB), and controls the operation of the engine actuation devices 32 of the engine or the operation of the brake actuation device 43 of the braking system such that the calculated required acceleration Gj is achieved. If the vehicle 10 is to be accelerated, the calculated required acceleration Gj is a positive value. Conversely, if the vehicle 10 is to be decelerated, the calculated required acceleration Gj is a negative value.

[0074] It should be noted that the final request acceleration Gj of the own vehicle 10, which is an acceleration obtained by adding the feedforward request acceleration GFF to the control request acceleration GFB, is referred to as "the CACC-requested G" in some cases. The CACC corresponding to cooperative following control is a control system that causes the own vehicle 10's acceleration to be equal to the CACC-requested G. The ACC corresponding to inter-vehicle distance control is a control system that causes the own vehicle 10's acceleration to be equal to the final request acceleration Gj, which is equal to the control request acceleration GFB, without using the feedforward request acceleration GFF.

[0075] The cooperative following control system can accelerate or decelerate the vehicle 10 while predicting the acceleration or deceleration of the communicating vehicle 11 ahead. Consequently, the inter-vehicle time T can be controlled to the target inter-vehicle time Ttgt with a high following capability. In other words, the vehicle 10 can be driven in precise following of the communicating vehicle 11 ahead.

[0076] If a guardrail is provided along the side of a road on which the own vehicle 10 is traveling, the own vehicle sensor 61 receives the wave reflected by the guardrail. In this case, the own vehicle sensor 61 simultaneously receives the waves reflected by the vehicle 11 ahead and the guardrail. Thus, the temporary state in which the sensor ECU 60 has not detected or captured the vehicle 11 ahead can occur. Additionally, if the height of the vehicle 11 ahead is high and the distance between the own vehicle 10 and the vehicle 11 ahead is small, the output wave passes under the vehicle 11 ahead, preventing the own vehicle sensor 61 from receiving the reflected wave. In this case as well, the temporary state in which the sensor ECU 60 has not detected the vehicle ahead can occur.

[0077] Furthermore, if the preceding vehicle 11 is present and the sensor ECU 60 has not yet detected it, the system proceeds to transmit the preceding vehicle's acceleration information from the vehicle already identified as the communicating preceding vehicle 11 to its own vehicle 10. Consequently, the exemplary embodiment control unit can calculate the forward control request acceleration (GFF) based on the communicating preceding vehicle's acceleration information, and the own vehicle 10 can accelerate based on the calculated forward control request acceleration (GFF).In this case, if the sensor ECU 60 has not detected the vehicle 11 ahead and as a result has not obtained the intermediate vehicle distance D, the own vehicle 10 will accelerate, whereby the excessive reduction of the intermediate vehicle distance between the own vehicle 10 and the vehicle 11 ahead or between the own vehicle 10 and a vehicle that comes between the own vehicle 10 and the vehicle 11 ahead may occur.

[0078] Accordingly, the exemplary control unit sets the feedforward acceleration GFF to 0 if it is determined that the sensor ECU 60 has not detected the preceding vehicle 11 and the calculated feedforward acceleration GFF is greater than 0. In other words, the exemplary control unit sets an upper limit for the feedforward acceleration GFF to 0. That is, the exemplary control unit limits the feedforward acceleration GFF to a value less than or equal to 0.

[0079] This prevents the acceleration of the vehicle 10, derived from the feedforward acceleration requirement (FAR), from being determined that the sensor ECU 60 has not detected the vehicle 11 ahead. As a result, the excessive reduction of the distance between vehicles is prevented.

[0080] If it is determined that the sensor ECU 60 has not detected the preceding vehicle 11 and the calculated feedforward acceleration request GFF is less than 0, the execution control unit uses the calculated feedforward acceleration request GFF as is to set the feedforward acceleration request Gj of the own vehicle 10. In this case, the own vehicle 10 is decelerated, thereby increasing the inter-vehicle distance, thus preventing the inter-vehicle distance D from decreasing excessively and preventing the occupants of the own vehicle 10 from experiencing discomfort. Furthermore, if the temporary condition occurs that the sensor ECU 60 has not detected the preceding vehicle 11, the following vehicle control can be smoothly restarted after the sensor ECU 60 has restarted detection of the preceding vehicle 11. < Actual Operation >

[0081] Next, the cooperative adaptive cruise control (CACC) implemented by the exemplary control unit will be described in detail. The CPU of the vehicle control ECU 20 is programmed or configured to execute a routine defined by a flowchart in Fig. As shown in Figure 2, the routine is to start every time a predetermined time elapses. Consequently, at a predetermined time, the CPU starts the execution of this routine from step 200 and then proceeds with processing to step 205 to determine whether the CACC switch 21 is positioned in the on position or not.

[0082] When the CACC switch 21 is in the ON position, the CPU determines "YES" in step 205 and then proceeds to step 210 to execute a routine defined by a flowchart in Fig. Figure 3 shows the process of starting to identify the communicating vehicle 11 ahead among the communicating vehicles that send information, including data on operating state variables, to the own vehicle 10 via wireless communication. That is, when the CPU progresses to step 210 with processing, the CPU starts the execution of the routine from step 300 according to Fig. 3 and then performs consecutive processing operations according to steps 305 and 310, which are described below. The CPU then proceeds to processing step 215 according to... Fig. 2, moving forward by one step 305.

[0083] Step 305: The CPU obtains the Ahead Vehicle Information, which includes the operating condition data of the ahead vehicle, from the Sensor ECU 60 and obtains the Communicating Vehicle Information, which includes the operating condition data of the communicating vehicles, from the Wireless Communication Control ECU 80.

[0084] Step 310: The CPU identifies the communicating vehicle ahead 11 among the communicating vehicles based on the operating state variables of the communicating vehicles contained in the Communicating Vehicle Information and the operating state variables of the vehicle ahead 11 contained in the Vehicle Ahead Information. For example, the CPU calculates the speed of the vehicle ahead 111 based on the relative speed dSPD obtained by the vehicle's own sensor 61 and the vehicle's own speed SPDj.Then, if the degree of similarity between the calculated speed of the vehicle ahead 11 and the speed of the communicating vehicle, which is transmitted by the communicating vehicle via wireless communication, is high, the CPU identifies this communicating vehicle as the communicating vehicle ahead 11.

[0085] It should be noted that once a specific communicating vehicle has been identified as the communicating leading vehicle 11 by performing the processing according to step 310, the identified communicating vehicle will be used as the communicating leading vehicle 11 until the CPU determines that the identified communicating vehicle is not the leading vehicle.

[0086] When the CPU proceeds to step 215, it determines whether the identification of the communicating preceding vehicle 11 in step 210 has been completed. If the identification of the communicating preceding vehicle 11 has been completed, the CPU determines "YES" in step 215 and then performs processing according to step 225, which is described below.

[0087] Step 225: The CPU calculates or obtains as the estimated acceleration Ges (= fh (Gs) + fl (Gas)) a total value of a value obtained by multiplying a value fh (Gs), obtained by filtering the request acceleration Gs of the communicating preceding vehicle 11 with the high-pass filter, by a predetermined positive coefficient kh (in this embodiment the coefficient kh is 1), and a value fl (Gas), obtained by filtering the actual acceleration Gas of the communicating preceding vehicle 11 with the low-pass filter, if the request acceleration Gs and the actual acceleration Gas in the communicating vehicle information obtained in step 210 (in particular step 305 according to Fig. 3) are obtained, include and relate to the communicating vehicle, which is the communicating preceding vehicle 11 in step 210 (in particular in step 310 according to Fig. 3) is identified. The Communicating Vehicle Information is referred to below as “the Communicating Ahead Vehicle Information” in some cases.

[0088] Alternatively, the CPU uses the actual acceleration Gas as the estimated acceleration Ges if no request acceleration Gs is included in the communicating vehicle ahead information and only the actual acceleration Gas is included in the communicating vehicle ahead information.

[0089] Next, the CPU proceeds to step 240 to determine whether the estimated acceleration Ges, calculated or obtained in step 225, is greater than zero. If the estimated acceleration Ges is greater than zero, the CPU determines "YES" in step 240 and then performs sequential processing according to steps 245 through 249, as described below. The CPU then proceeds to step 260.

[0090] Step 245: The CPU sets a first correction coefficient Klac for acceleration as the first correction coefficient K1. The first correction coefficient Klac for acceleration is a constant value less than one. Therefore, the first correction coefficient Klac for acceleration can be one.

[0091] Step 247: The CPU applies the inter-vehicle time T to a lookup table MapK2(T)_ac, which is located in Fig. Figure 6(A) shows how to obtain the second correction coefficient K2 for acceleration. According to the lookup table MapK2(T)_ac, if the inter-vehicle time T is between zero and time T1, the second correction coefficient K2 for acceleration is zero. If the inter-vehicle time T is between time T1 and time T2, the second correction coefficient K2 for acceleration is a value less than or equal to one, increasing as the inter-vehicle time T increases. If the inter-vehicle time T is between time T2 and time T3, the second correction coefficient K2 for acceleration is one. If the inter-vehicle time T is between time T3 and time T4, the second correction coefficient K2 for acceleration is a value less than or equal to one, decreasing as the inter-vehicle time T increases.If the intermediate vehicle time T is greater than the time T4, the second correction coefficient K2 for acceleration is zero.

[0092] Step 249: The CPU applies the vehicle's own speed SPDj to a lookup table MapK3(SPDj)_ac, which is located in Fig. Figure 6(C) shows how to obtain the third correction coefficient K3 for acceleration. According to the lookup table MapK3(SPDj)_ac, if the vehicle speed SPDj is between zero and vehicle speed SPDj1, the third correction coefficient K3 for acceleration is zero. If the vehicle speed SPDj is between vehicle speed SPDj1 and vehicle speed SPDj2, the third correction coefficient K3 for acceleration is less than or equal to one, increasing as the vehicle speed SPDj increases. If the vehicle speed SPDj is between vehicle speed SPDj2 and vehicle speed SPDj3, the third correction coefficient K3 for acceleration is one.If the vehicle's own speed SPDj lies between vehicle speed SPDj3 and vehicle speed SPDj4, the third correction coefficient K3 for acceleration is less than or equal to one, decreasing as the vehicle's own speed SPDj increases. If the vehicle's own speed SPDj is greater than vehicle speed SPDj4, the third correction coefficient K3 for acceleration is zero.

[0093] If the estimated acceleration Ges is less than or equal to 0 when executing the processing according to step 240, the CPU determines "NO" in step 240 and then sequentially executes processing according to steps 250 through 254, which are described below. The CPU then proceeds with processing to step 260.

[0094] Step 250: The CPU sets a first correction coefficient Klde for delay as the first correction coefficient K1. The first correction coefficient Klde for delay is a constant value less than one and greater than or equal to the first correction coefficient Klac for acceleration. Therefore, the first correction coefficient Klde for delay can be one.

[0095] Step 252: The CPU applies the inter-vehicle time T to a lookup table MapK2(T)_de, which is located in Fig. Figure 6(B) shows how to obtain the second correction coefficient K2 for the delay. According to the lookup table MapK2(T)_de, if the inter-vehicle time T is between zero and time T5, the second correction coefficient K2 for the delay is one. If the inter-vehicle time T is between time T5 and time T6, the second correction coefficient K2 for the delay is less than or equal to one, decreasing as the inter-vehicle time T increases. If the inter-vehicle time T is greater than time T6, the second correction coefficient K2 for the delay is zero.

[0096] Step 254: The CPU applies the vehicle's own speed SPDj to a lookup table MapK3(SPDj)_de, which is located in Fig. Figure 6(D) shows how to obtain the third correction coefficient K3 for deceleration. According to the lookup table MapK3(SPDj)_de, if the vehicle speed SPDj is between zero and vehicle speed SPDj5, the third correction coefficient K3 for deceleration is zero. If the vehicle speed SPDj is between vehicle speed SPDj5 and vehicle speed SPDj6, the third correction coefficient K3 for deceleration is less than or equal to one, increasing as the vehicle speed SPDj increases. If the vehicle speed SPDj is greater than vehicle speed SPDj6, the third correction coefficient K3 for deceleration is less than or equal to one, increasing as the vehicle speed SPDj increases.

[0097] When the CPU progresses to step 260, it starts executing a feedforward request acceleration calculation routine, which is described by a flowchart in Fig. Figure 4 shows how to calculate the feedforward request acceleration (GFF). Consequently, when the CPU advances to step 260 with processing, the CPU starts executing the routine from step 400 according to... Fig. 4, where it then proceeds with processing to step 405 to determine whether an elapsed time Tk, representing the time that has passed since the sensor ECU 60 did not detect the vehicle ahead, is less than a predetermined time Tkth (in this embodiment, one second). In this respect, if the sensor ECU 60 detects the vehicle ahead, the elapsed time Tk is set to zero.

[0098] If the elapsed time Tk is less than the predetermined time Tkth, the CPU determines “YES” in step 405, and then proceeds to processing step 410 to calculate or obtain the feedforward request acceleration GFF according to an expression (1) below. GFF=Total×K1×K2×K3

[0099] In expression (1), the symbol “Ges” is the estimated acceleration taken in step 225 according to Fig. 2 is calculated or obtained, the symbol “K1” is the first correction value set in step 245 or 250, the symbol “K2” is the second correction value set in step 247 or 252, and the symbol “K3” is the third correction value set in step 249 or 254.

[0100] Next, the CPU proceeds to step 415 to determine whether or not sensor ECU 60 has detected the vehicle ahead. Sensor ECU 60 sends a signal to vehicle control ECU 20 indicating whether or not it has detected the vehicle ahead. The CPU then performs the determination processing in step 415 based on the signal provided by sensor ECU 60. If sensor ECU 60 has not detected the vehicle ahead, the CPU determines "NO" in step 415 and then proceeds to step 432 to increment the elapsed time Tk by a predetermined value dTk.

[0101] Next, the CPU proceeds to step 435 to determine whether the feedforward request acceleration (GFF), calculated in step 410, is greater than zero. If the feedforward request acceleration (GFF) is greater than zero, the CPU determines "yes" in step 435 and then proceeds to step 440 to set the feedforward request acceleration (GFF) to zero. The CPU then proceeds to step 265 according to... Fig. 2, one step forward, 495.

[0102] In contrast, if the feedforward request acceleration (GFF) is less than or equal to zero during the execution of step 435, the CPU determines "NO" in step 435 and then proceeds directly to step 265 according to Fig. 2 progresses beyond step 495. As a result, the feedforward request acceleration (GFF) is limited to a value less than or equal to zero if the sensor ECU 60 has not detected the vehicle ahead.

[0103] In contrast, if the sensor ECU 60 detects the vehicle ahead during the execution of step 415, the CPU determines "YES" in step 415, then proceeds with the processing to step 417 to delete the elapsed time Tk.

[0104] Next, the CPU proceeds with processing to step 420 to determine whether the preceding vehicle, identified as detected in step 415, corresponds to a vehicle realized by the Wireless Communication Control ECU 80 as the communicating vehicle.

[0105] If the vehicle ahead, which is determined to have been detected during the execution of step 420, corresponds to the communicating vehicle, that is, the communicating vehicle is the vehicle ahead, the CPU proceeds with processing to step 265 according to Fig. 2. Proceed via step 495. In this case, the feedforward control request acceleration (FCE) has been set to a value that is calculated in step 410.

[0106] In contrast, if the preceding vehicle detected during the execution of step 420 is not the communicating vehicle, the CPU determines "NO" in step 420 and then proceeds to step 430 to set the feedforward acceleration (GFF) to zero. That is, if the communicating vehicle, currently realized as the communicating preceding vehicle 11, is not the preceding vehicle, the communicating vehicle cannot be the communicating preceding vehicle 11, and accordingly, the CPU sets the feedforward acceleration (GFF) to zero. The CPU then proceeds to step 265 according to... Fig. 2 proceeds via step 495. In this case, the intermediate vehicle distance control, which is a control or feedback control, is executed according to the demand acceleration Gj (= GFB), which is calculated solely on the basis of the control demand acceleration GFB.

[0107] If the elapsed time Tk is greater than or equal to the predetermined time Tkth during the execution of step 405, the CPU determines "NO" in step 495 and then proceeds to step 450 to set the feedforward request acceleration GFF to zero. The CPU then proceeds to step 265 according to... Fig. 2 proceeds via step 495. In this case, as described below, the control request acceleration GFB is set to zero (see step 570 according to). Fig. 5), consequently stopping the cooperation following control and the inter-vehicle distance control.

[0108] When the CPU proceeds with processing to step 265, it executes a control request acceleration calculation routine, which is represented by a flowchart in Fig. Figure 5 shows how to calculate the control request acceleration (GFB). That is, when the CPU progresses to step 265, the CPU starts an execution of the routine from step 500 according to... Fig. 5, where it then proceeds to step 505 to obtain the relative vehicle speed dSPD. The CPU then proceeds to step 510 to determine whether the sensor ECU 60 has detected the communicating vehicle 11 ahead or not.

[0109] When the sensor ECU 60 has detected the communicating preceding vehicle 11, the CPU determines “YES” in step 510, and then performs successive processing operations according to steps 515 to 525, which are described below.

[0110] Step 515: The CPU calculates or obtains the target inter-vehicle distance Dtgt by multiplying the target inter-vehicle time Ttgt by the vehicle's own speed SPDj (Dtgt = Ttgt x SPDj). As described above, the target inter-vehicle time Ttgt is set to a constant value.

[0111] Step 520: The CPU calculates or obtains the inter-vehicle distance difference dD by subtracting the target inter-vehicle distance Dtgt from the inter-vehicle distance D (dD = D - Dtgt).

[0112] Step 525: The CPU calculates or obtains the intended use calculation value P according to an expression (2) below. P=dD×KFB1+dSPD×KFB2

[0113] In expression (2) the symbol “dD” is the inter-vehicle distance difference calculated in step 520, the symbol “dSPD” is the relative speed between the own vehicle 10 and the vehicle ahead, and the symbols “KFB1” and “KFB2” are correction coefficients which are positive constant values ​​greater than zero.

[0114] The CPU then proceeds to step 530 to determine whether the destination usage calculation value P is greater than zero. A destination usage calculation value P greater than zero indicates that an acceleration request due to the inter-vehicle distance D occurs in the own vehicle 10, while a destination usage calculation value P less than or equal to zero indicates that no acceleration request due to the inter-vehicle distance D occurs in the own vehicle 10.

[0115] If the determination usage calculation value P is greater than zero, the CPU determines "YES" in step 530, then proceeds to step 535 to calculate or obtain the control request acceleration GFB according to expression (3) below. The CPU then proceeds to step 270 according to Fig. 2 advances by one step 595. GFB=(dD×KFB1+dSPD×KFB2)×KFB3

[0116] In expression (3) the symbol “KFB3” is a correction coefficient which is a positive value greater than zero and less than one, decreasing as the own vehicle speed SPDj increases.

[0117] In contrast, if the determination usage calculation value P is less than or equal to zero during the execution of step 530, the CPU determines "NO" in step 530 and then proceeds with processing to step 545 to calculate or obtain the control request acceleration GFB according to expression (4) below. The CPU then proceeds with processing to step 270 according to Fig. 2 beyond step 595. GFB=dD×KFB1+dSPD×KFB2

[0118] In contrast, if the sensor ECU 60 has not detected the vehicle ahead (i.e., the communicating vehicle ahead 11) during the execution of the processing of step 510, the CPU determines “NO” in step 510, and then proceeds with the processing to step 555 to determine whether the elapsed time Tk since the sensor ECU 60 did not detect the vehicle ahead is less than the predetermined time Tkth (in this embodiment, one second) or not.

[0119] If the elapsed time Tk is less than the predetermined time Tkth, the CPU determines "YES" in step 555, then executes processing step 560, which is described below. The CPU then proceeds to processing step 270 according to... Fig. 2 beyond step 595.

[0120] Step 560: The CPU maintains the currently set control request acceleration GFB. This means that the control request acceleration GFB is maintained at a value that is set immediately before the sensor ECU 60 fails to detect the vehicle ahead (i.e., the communicating vehicle ahead 11).

[0121] In contrast, if the elapsed time Tk is greater than or equal to the predetermined time Tkth during the execution of step 555, the CPU determines "NO" in step 555 and then executes step 570, which is described below. The CPU then proceeds to step 270 according to... Fig. 2 beyond step 595.

[0122] Step 570: The CPU sets the control request acceleration GFB to zero. In this case, the feedforward request acceleration GFF is also set to zero in step 450 according to Fig. 4 is set, thus stopping the cooperation following control and the inter-vehicle distance control.

[0123] When the CPU is processing step 270 according to Fig. As step 2 progresses, the CPU calculates or obtains the request acceleration Gj of its own vehicle 10 by adding the control request acceleration GFB, which is calculated in step 265, to the feedforward request acceleration GFF, which is calculated in step 260 (Gj = GFF + GFB).

[0124] The CPU then proceeds to step 275 to perform operations for activating the power machine actuation devices 32 or the brake actuation device 43 of the braking system, so that the requested acceleration Gj, calculated in step 270, is achieved. This means that the acceleration (specifically, acceleration / deceleration) of the vehicle 10 corresponds to the requested acceleration Gj. If the requested acceleration Gj is greater than zero, the vehicle 10 accelerates. Conversely, if the requested acceleration Gj is less than zero, the vehicle 10 decelerates. The CPU then proceeds to step 295 to complete the execution of this routine once.

[0125] It should be noted that if the CACC switch 21 is in the OFF position during the execution of step 205, the CPU determines "NO" in step 205 and then proceeds directly to step 295 to complete the execution of this routine once. In this case, the cooperative following control is not executed.

[0126] Furthermore, if the identification of the communicating preceding vehicle 11 has not been completed during the execution of step 215, the CPU determines “NO” in step 215, and then proceeds directly to step 295 to complete the execution of this routine once.

[0127] It should be noted that if the identification of the communicating preceding vehicle 11 has not been completed and a vehicle is identified as the preceding vehicle 11 by the own vehicle sensor 61 and the sensor ECU 60—in other words, if the relative vehicle speed dSPD, the inter-vehicle distance D, the relative orientation, and the like have not been obtained during the execution of processing step 215—the CPU can proceed with processing to step 265 after the CPU has set the feedforward request acceleration GFF to 0. In this case, the inter-vehicle distance control (i.e., the control or feedback control) for controlling the acceleration or deceleration of the own vehicle 10 is executed using the request acceleration Gj (= GFB), which is calculated based solely on the control request acceleration GFB.

[0128] The cooperative following control has been described in detail. According to this cooperative following control, if the sensor ECU 60 has not detected the vehicle ahead (i.e., the communicating vehicle ahead 11) and the feedforward acceleration requirement (FER) is greater than zero, the feedforward acceleration requirement (FER) is set to zero (see steps 435 and 440). Consequently, as described above, an excessive reduction in the distance between the vehicle 10 and the vehicle ahead is prevented.

[0129] It should be noted that if the sensor ECU 60 has not identified the vehicle ahead as the communicating vehicle ahead 11, for example, if the brake actuation value Brkp of the communicating vehicle ahead 11 increases or one of the wheel speeds ωa to ωd of the communicating vehicle ahead 11 decreases and the feedforward acceleration request GFF is a negative value, the feedforward acceleration request GFF is taken into account when calculating the demand acceleration Gj of the own vehicle 10 without setting the feedforward acceleration request GFF to zero (see the determination of "NO" in step 435). Consequently, if the communicating vehicle ahead 11 begins to decelerate, the own vehicle 10 will decelerate according to the prediction of the deceleration of the communicating vehicle ahead 11.Thus, the own vehicle 10 is instructed to follow the communicating preceding vehicle 11 exactly, without reducing the intermediate vehicle distance D.

[0130] The present invention is not limited to the exemplary embodiment, and various modifications within a scope of the present invention may be used.

[0131] For example, if the estimated acceleration Ges is greater than zero, the control device can be configured according to the exemplary embodiment to simply calculate the feedforward acceleration request GFF, which is obtained by multiplying the estimated acceleration Ges by a predetermined positive correction coefficient Kllac (GFF = Ges x Kllac).

[0132] Furthermore, if the estimated acceleration Ges is less than or equal to zero, the control device can be configured according to the exemplary embodiment to simply calculate the feedforward acceleration request GFF, which is obtained by multiplying the estimated acceleration Ges by a predetermined positive correction coefficient Klde (GFF = Ges x Klde).

[0133] Furthermore, in step 270, the total value of the control request acceleration GFB and the feedforward request acceleration GFF is calculated as the request acceleration Gj of the own vehicle 10. However, a weighted average value of the control request acceleration GFB and the feedforward request acceleration GFF can, for example, be calculated as the request acceleration Gj of the own vehicle 10. In other words, the request acceleration Gj of the own vehicle 10 can be calculated according to expression (5) below. In expression (5), the symbols “α” and “β” are positive constants. The constants α and β are greater than zero and less than one, where the constant α can be a value 1 - β. Gj=α×GFF+β×GFB

[0134] Furthermore, the control unit can be configured according to the exemplary embodiment to simply calculate the control request acceleration GFB, a value obtained by multiplying the inter-vehicle distance difference dD by a predetermined correction coefficient KFB (GFB = KFB x dD). The correction coefficient KFB is a constant positive value greater than zero.

[0135] In addition, according to the exemplary embodiment, the control unit calculates the feedforward acceleration request GFF based on the request acceleration Gs and the actual acceleration (throttle position) of the communicating preceding vehicle 11, which are obtained through wireless communication. In this respect, the control unit can calculate the feedforward acceleration request GFF based solely on the request acceleration Gs, without using the actual acceleration (throttle position), or solely on the basis of the actual acceleration (throttle position), without using the request acceleration Gs.

[0136] Furthermore, if the accelerator pedal actuation quantity Accp and the brake pedal actuation quantity Brkp are sent by the communicating preceding vehicle 11 instead of the request acceleration Gs, the control unit can be configured according to the embodiment to obtain the accelerator pedal actuation quantity Accp and the brake pedal actuation quantity Brkp as information about the request acceleration Gs of the communicating preceding vehicle 11, to estimate the request acceleration Gs of the communicating preceding vehicle 11 based on the accelerator pedal actuation quantity Accp and the brake pedal actuation quantity Brkp, and to calculate the feedforward request acceleration GFF using the estimated request acceleration Gs.

[0137] Similarly, if the vehicle wheel speeds ωa to ωd or the average vehicle wheel speed wave is / are sent by the communicating preceding vehicle 11 instead of the actual acceleration gas, the control unit according to the embodiment can be configured to obtain the vehicle wheel speeds ωa to ωd or the average vehicle wheel speed wave as information about the actual acceleration gas of the communicating preceding vehicle 11, to estimate the actual acceleration gas of the communicating preceding vehicle 11 based on the vehicle wheel speeds ωa to ωd or the average vehicle wheel speed wave, and to calculate the feedforward acceleration request GFF using the estimated actual acceleration gas.

[0138] The control unit according to the embodiment maintains the control request acceleration GFB until the time Tk that has elapsed since the sensor ECU 60 did not detect the vehicle ahead exceeds the predetermined time Tkth.

[0139] In this regard, the control unit can be configured to gradually decrease the control request acceleration GFB until the time Tk elapsed since the sensor ECU 60 failed to detect the vehicle ahead exceeds the predetermined time Tkth. Additionally, the vehicle's own sensor 61 can be configured to emit and receive a wave, such as a light wave (e.g., a laser) or an ultrasonic wave, instead of the millimeter wave.

[0140] The invention relates to a control unit for a vehicle (10). The unit calculates a demand acceleration (Gj) of the vehicle itself based on control and feedforward demand accelerations (GFB and GFF) and executes a follow-drive control to cause the vehicle itself to follow a communicating preceding vehicle (11) by controlling the acceleration of the vehicle itself such that its acceleration corresponds to the demand acceleration (Gj). The unit sets the feedforward demand acceleration (GFF) to zero if a vehicle sensor device (60) has not detected the preceding vehicle and the feedforward demand acceleration (GFF) is greater than zero after an execution of the follow-drive control has been initiated.

Claims

[1] Control unit of a vehicle (10) comprising: a vehicle-specific sensor (61) configured to output a wave in front of a vehicle (10) and to detect a reflected wave of the output wave; a vehicle-to-own sensor device (60) configured to detect a vehicle traveling in front of the vehicle (10) as a vehicle ahead based on the reflected wave detected by the vehicle-to-own sensor (61), and to obtain an intermediate vehicle distance (D) between the vehicle (10) and the vehicle ahead based on the reflected wave; a wireless communication device (80, 81) configured to receive communicating vehicle ahead information, including communicating vehicle ahead acceleration information (Gs, Gas) about the acceleration of a communicating vehicle ahead (11), wherein the communicating vehicle ahead (11) is the vehicle ahead that has a wireless communication function; and an acceleration / deceleration control device (20, 30, 40) configured to control the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to a demand acceleration (Gj) of the own vehicle (10); the acceleration / deceleration control device (20, 30, 40) comprises: a first computation device configured to calculate a control request acceleration (CRE) based on the inter-vehicle distance (D) and a target inter-vehicle distance (Dtgt), wherein the control request acceleration (CRE) is an acceleration requested at the own vehicle (10) to maintain the inter-vehicle distance (D) at the target inter-vehicle distance (Dtgt); a second computing device configured to calculate a forward control request acceleration (GFF) based on the communicating vehicle ahead acceleration information (Gs, Gas), wherein the forward control request acceleration (GFF) is an acceleration requested from the own vehicle (10) to cause the own vehicle (10) to follow the communicating vehicle ahead (11); and a third calculating device configured to calculate the request acceleration (Gj) of the own vehicle (10) based on the control and feedforward request accelerations (GFB and GFF), wherein the acceleration / deceleration control device (20, 30, 40) is configured to perform a following driving control to cause the own vehicle (10) to follow the communicating preceding vehicle (11) by controlling the acceleration of the own vehicle (10) such that the acceleration of the own vehicle (10) corresponds to the requested acceleration (Gj) calculated by the third calculating device, characterized by , that the third computing unit is configured, to set the pre-control request acceleration (PCE) to zero if the vehicle's own sensor device (60) has not detected the vehicle ahead and the pre-control request acceleration (PCE) is greater than zero after an execution of the follow-up control has been started, and to adjust the feedforward acceleration (GFF) to the calculated feedforward acceleration (GFF) if the vehicle's own sensor device (60) has not detected the vehicle ahead and the feedforward acceleration (GFF) is less than zero after the execution of the follow-up driving control has been started. [2] Vehicle control device according to claim 1, wherein the acceleration / deceleration control device (20, 30, 40) is configured to stop controlling the acceleration of the own vehicle (10) using the Communicating Ahead Vehicle acceleration information (Gs, Gas) when an elapsed time becomes greater than or equal to a predetermined time, wherein the elapsed time is a time that has elapsed since the own vehicle sensor (61) did not detect the ahead vehicle after the execution of the follow-drive control has been started. [3] Control device of the vehicle according to one of claims 1 and 2, wherein the Communicating Ahead Vehicle Acceleration Information (Gs, Gas) comprises information about a request acceleration (Gs) of the communicating ahead vehicle (11) which is calculated by the communicating ahead vehicle (11) on the basis of operating parameters (Accp, Brkp) of an acceleration operator and a braking operator of the communicating ahead vehicle (11). [4] Vehicle control unit according to any one of claims 1 to 3, wherein the communicating vehicle ahead acceleration information (Gs, Gas) comprises information about a request acceleration (Gs) of the communicating vehicle ahead (11), which is calculated by a control unit of the communicating vehicle ahead (11) on the basis of information about the acceleration of a vehicle traveling in front of the communicating vehicle ahead (11), which is obtained by a wireless communication device of the communicating vehicle ahead (11) from the vehicle traveling in front of the communicating vehicle ahead (11), when the control unit of the communicating vehicle ahead (11) performs the same control as the following vehicle control to cause the communicating vehicle ahead (11) to respond to the vehicle traveling in front of the communicating vehicle ahead.to drive as follows.

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