Patent Publication Number: US-2022234653-A1

Title: Vehicle collision avoidance assist apparatus

Description:
BACKGROUND 
     Field 
     The invention relates to a vehicle collision avoidance assist apparatus. 
     Description of the Related Art 
     There is known a vehicle collision avoidance assist apparatus which executes a forcibly braking control of forcibly braking and stopping an own vehicle to avoid collision of the own vehicle with an object ahead of the own vehicle when the own vehicle probably collides with the object. Also, there is known a vehicle collision avoidance assist apparatus which executes a steering avoidance control of forcibly steering the own vehicle to avoid the object to avoid the collision of the own vehicle with the object when the vehicle collision avoidance assist apparatus predicts that the own vehicle cannot avoid the collision with the object even by forcibly braking the own vehicle (for example, see JP 2017-43262 A). 
     While the known vehicle collision avoidance assist apparatus executes the steering avoidance control, the known vehicle collision avoidance assist apparatus sets an avoidance route along which the known vehicle collision avoidance assist apparatus moves the own vehicle, avoiding the object and steers the own vehicle to move along the avoidance route. However, when the object ahead of the own vehicle is a moving object such as a preceding vehicle which moves in the same direction as a moving direction of the own vehicle, the moving object may be decelerated after the known vehicle collision avoidance assist apparatus starts moving the own vehicle along the avoidance route. In this case, the own vehicle may rapidly approach the moving object, and the avoidance route may become close to or cross the moving object. If an execution of the steering avoidance control is continued when the own vehicle rapidly approaches the moving object, and the avoidance route becomes close to or crosses the moving object, the own vehicle may collide with the moving object. 
     SUMMARY 
     An object of the invention is to provide a vehicle collision avoidance assist apparatus which can prevent collision of the own vehicle with the moving object when the moving object is decelerated while the vehicle collision avoidance assist apparatus executes the steering avoidance control. 
     According to the invention, a vehicle collision avoidance assist apparatus comprises an electronic control unit configured to execute a steering avoidance control. The steering avoidance control is a control of setting an avoidance route for avoiding the collision of the own vehicle with the object in a lane in which the own vehicle moves, and executing an avoiding steering process of forcibly steering the own vehicle so as to move the own vehicle along the avoidance route, when an index value representing a probability of collision of an own vehicle with an object ahead of the own vehicle becomes equal to or greater than a predetermined index value. The electronic control unit is configured to stop executing the steering avoidance control when (i) the object is a moving object which moves in the same direction as a moving direction of the own vehicle, and (ii) a deceleration of the moving object becomes equal to or greater than a predetermined deceleration. 
     When the object with which the own vehicle is avoiding the collision, is the moving object, and the moving object is decelerated, the own vehicle may rapidly approach the moving object, and the avoidance route may become close to or cross the moving object. If the execution of the steering avoidance control is continued after the avoidance route becomes close to or cross the moving object, the own vehicle may collide with the moving object. According to the invention, when the moving object is decelerated, and the deceleration of the moving object becomes equal to or greater than the predetermined deceleration while the steering avoidance control is executed, the execution of the steering avoidance control is stopped. Thus, the own vehicle can be prevented from colliding with the moving object even when the moving object is decelerated. 
     According to an aspect of the invention, the avoidance route may be set, based on a relative moving speed of the own vehicle with respect to the moving object at a point of time when the index value becomes equal to or greater than the predetermined index value. 
     When the moving object is decelerated, the relative moving speed of the own vehicle with respect to the moving object is increased. Thus, if the avoidance route is set, based on the relative moving speed of the own vehicle with respect to the moving object at the point of time when the index value becomes equal to or greater than the predetermined index value, whether the moving object is decelerated or not considerably influences whether the own vehicle collides with the moving object when the own vehicle is moved along the avoidance route. According to this aspect of the invention, the avoidance route is set, based on the relative moving speed of the own vehicle with respect to the moving object. Then, when the deceleration of the moving object becomes equal to or greater than the predetermined deceleration, the execution of the steering avoidance control is stopped. Thus, the own vehicle can be surely prevented from colliding with the moving object. 
     According to another aspect of the invention, the index value may be a predicted reaching time which is a time predictively taken for the own vehicle to reach the object. In this aspect, the index value may increase as the predicted reaching time decreases. Further, in this aspect, the predicted reaching time may be acquired, based on (i) a distance between the own vehicle and the object and (ii) a relative moving speed of the own vehicle with respect to the object. Furthermore, the steering avoidance control may be executed when the predicted reaching time becomes a predetermined predicted reaching time which corresponds to the predetermined index value. 
     In order to execute the steering avoidance control with preventing an unnecessary execution of the steering avoidance control, it is effective to determine a timing of starting the execution of the steering avoidance control, based on the time taken for the own vehicle to reach the object. With this aspect of the invention, whether the execution of the steering avoidance control should be started, is determined, based on the time predictively taken for the own vehicle to reach the object (i.e., the predicted reaching time) as the index value. Thus, the steering avoidance control can be executed with preventing the unnecessary execution of the steering avoidance control. 
     Elements of the invention are not limited to elements of embodiments and modified examples of the invention described with reference to the drawings. The other objects, features and accompanied advantages of the invention can be easily understood from the embodiments and the modified examples of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view which shows a vehicle collision avoidance assist apparatus according to an embodiment of the invention and an own vehicle on which the vehicle collision avoidance assist apparatus according to the embodiment of the invention is installed. 
         FIG. 2A  is a view which shows lane markings which define a lane in which the own vehicle moves. 
         FIG. 2B  is a view which shows a yaw angle of the own vehicle. 
         FIG. 2C  is a view which shows the yaw angle of the own vehicle. 
         FIG. 3A  is a view which shows an own vehicle moving area. 
         FIG. 3B  is a view which shows a scene that a vehicle as an object is in the own vehicle moving area. 
         FIG. 3C  is a view which shows a recommended avoidance route along which the own vehicle is moved to avoid the vehicle as the object. 
         FIG. 3D  is a view which shows a target avoidance route along which the own vehicle is moved to avoid the vehicle as the object. 
         FIG. 4A  is a view which shows a scene that an execution of a steering process or an avoiding steering process of steering the own vehicle to move the own vehicle along the avoidance route, is started. 
         FIG. 4B  is a view which shows a scene that the avoiding steering process is being executed. 
         FIG. 4C  is a view which shows a scene that an execution of a steering avoidance control is terminated. 
         FIG. 5A  is a view which shows a scene that the execution of the steering process or the avoiding steering process of steering the own vehicle to move the own vehicle along the avoidance route is started. 
         FIG. 5B  is a view which shows a situation which may occur if the execution of the avoiding steering process or the steering avoidance control is continued when a preceding vehicle as the object ahead of the own vehicle is decelerated, the own vehicle rapidly approaches the preceding vehicle as the object, and the avoidance route becomes close to or crosses the preceding vehicle as the object. 
         FIG. 6  is a view which shows a time chart which illustrates changes of a deceleration of a target moving object, etc. when the execution of the steering avoidance control is not terminated without the execution of the steering avoidance control being stopped halfway. 
         FIG. 7  is a view which shows a time chart which illustrates the changes of the deceleration of the target moving object, etc. when the execution of the steering avoidance control is stopped halfway. 
         FIG. 8  is a view which shows a flowchart of a routine executed by the vehicle collision avoidance assist apparatus according to the embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Below, a vehicle collision avoidance assist apparatus according to an embodiment of the invention will be described with reference to the drawings. As shown in  FIG. 1 , the vehicle collision avoidance assist apparatus  10  according to the embodiment of the invention is installed on an own vehicle  100 . 
     &lt;ECU&gt; 
     As shown in  FIG. 1 , the vehicle collision avoidance assist apparatus  10  includes an ECU  90 . ECU stands for electronic control unit. The ECU  90  includes a micro-computer as a main component. The micro-computer includes a CPU, a ROM, a RAM, a non-volatile, and an interface. The CPU is configured or programmed to realize various functions by executing instructions, programs, or routines stored in the ROM. 
     &lt;Driving Apparatus, Etc.&gt; 
     Moreover, a driving apparatus  21 , a braking apparatus  22 , and a steering apparatus  23  are installed on the own vehicle  100 . 
     &lt;Driving Apparatus&gt; 
     The driving apparatus  21  is an apparatus which outputs a driving force to be applied to the own vehicle  100  to move the own vehicle  100 . The driving apparatus  21  is, for example, an internal combustion engine and at least one electric motor. The driving apparatus  21  is electrically connected to the ECU  90 . The ECU  90  can control the driving force output from the driving apparatus  21  by controlling an activation of the driving apparatus  21 . 
     &lt;Braking Apparatus&gt; 
     The braking apparatus  22  is an apparatus which outputs a braking force to be applied to the own vehicle  100  to brake the own vehicle  100 . The braking apparatus  22  is, for example, a brake apparatus. The braking apparatus  22  is electrically connected to the ECU  90 . The ECU  90  can control the braking force output from the braking apparatus  22  by controlling an activation of the braking apparatus  22 . 
     &lt;Steering Apparatus&gt; 
     The steering apparatus  23  is an apparatus which outputs a steering force to be applied to the own vehicle  100  to steer the own vehicle  100 . The steering apparatus  23  is, for example, a power steering apparatus. The steering apparatus  23  is electrically connected to the ECU  90 . The ECU  90  can control the steering force output from the steering apparatus  23  by controlling an activation of the steering apparatus  23 . 
     &lt;Sensors, Etc.&gt; 
     Moreover, an accelerator pedal operation amount sensor  61 , a brake pedal operation amount sensor  62 , a steering angle sensor  63 , a steering torque sensor  64 , a vehicle moving speed sensor  65 , a longitudinal acceleration sensor  66 , a lateral acceleration sensor  67 , and a forward information detection apparatus  68 . 
     &lt;Accelerator Pedal Operation Amount Sensor&gt; 
     The accelerator pedal operation amount sensor  61  is electrically connected to the ECU  90 . The accelerator pedal operation amount sensor  61  detects an operation amount of an accelerator pedal  31 . The accelerator pedal operation amount sensor  61  sends information on the detected operation amount to the ECU  90 . The ECU  90  acquires the operation amount of the accelerator pedal  31  as an accelerator pedal operation amount AP, based on the information sent from the accelerator pedal operation amount sensor  61 . The ECU  90  calculates and acquires a requested driving force PDreq, based on the accelerator pedal operation amount AP and a vehicle moving speed V 100  of the own vehicle  100 . The requested driving force PDreq is a driving force requested for the driving apparatus  21  to output. 
     &lt;Brake Pedal Operation Amount Sensor&gt; 
     The brake pedal operation amount sensor  62  is electrically connected to the ECU  90 . The brake pedal operation amount sensor  62  detects an operation amount of a brake pedal  32 . The brake pedal operation amount sensor  62  sends information on the detected operation amount to the ECU  90 . The ECU  90  acquires the operation amount of the brake pedal  32  as a brake pedal operation amount BP, based on the information sent from the brake pedal operation amount sensor  62 . The ECU  90  calculates and acquires a requested braking force PBreq, based on the brake pedal operation amount BP. The requested braking force PBreq is a braking force requested for the braking apparatus  22  to output. 
     &lt;Steering Angle Sensor&gt; 
     The steering angle sensor  63  is electrically connected to the ECU  90 . The steering angle sensor  63  detects a rotation angle of a steering wheel  33  of the own vehicle  100  from a neutral position of the steering wheel  33 . The steering angle sensor  63  sends information on the detected rotation angle to the ECU  90 . The ECU  90  acquires the rotation angle of the steering wheel  33  from the neutral position as a steering angle SA, based on the information sent from the steering angle sensor  63 . 
     &lt;Steering Torque Sensor&gt; 
     The steering torque sensor  64  is electrically connected to the ECU  90 . The steering torque sensor  64  detects a torque which a driver of the own vehicle  100  inputs to a steering shaft  34  via the steering wheel  33 . The steering torque sensor  64  sends information on the detected torque to the ECU  90 . The ECU  90  acquires the torque which the driver inputs to the steering shaft  34  via the steering wheel  33  as a driver input torque TQdr, based on the information sent from the steering torque sensor  64 . 
     &lt;Vehicle Moving Speed Sensor&gt; 
     The vehicle moving speed sensor  65  is electrically connected to the ECU  90 . The vehicle moving speed sensor  65  detects rotation speeds of wheels of the own vehicle  100 . The vehicle moving speed sensor  65  sends information on the detected rotation speeds of the wheels of the own vehicle  100 . The ECU  90  acquires the moving speed of the own vehicle  100  as the vehicle moving speed V 100 , based on the information sent from the vehicle moving speed sensor  65 . 
     In addition, the ECU  90  calculates and acquires a torque to be applied to the steering shaft  34  from the steering apparatus  23  as an assist steering torque TQas, based on the driver input torque TQdr and the vehicle moving speed V 100 . The assist steering torque TQas is a torque applied to the steering shaft  34  to assist a steering operation to the steering wheel  33  carried out by the driver. 
     &lt;Longitudinal Acceleration Sensor&gt; 
     The longitudinal acceleration sensor  66  is electrically connected to the ECU  90 . The longitudinal acceleration sensor  66  detects an acceleration of the own vehicle  100  in a longitudinal direction of the own vehicle  100 . The longitudinal acceleration sensor  66  sends information on the detected acceleration to the ECU  90 . The ECU  90  acquires the acceleration of the own vehicle  100  in the longitudinal direction of the own vehicle  100  as a longitudinal acceleration Gx, based on the information sent from the longitudinal acceleration sensor  66 . 
     &lt;Lateral Acceleration Sensor&gt; 
     The lateral acceleration sensor  67  is electrically connected to the ECU  90 . The lateral acceleration sensor  67  detects an acceleration of the own vehicle  100  in a lateral direction of the own vehicle  100 . The lateral acceleration sensor  67  sends information on the detected acceleration to the ECU  90 . The ECU  90  acquires the acceleration of the own vehicle  100  in the lateral direction of the own vehicle  100  as a lateral acceleration Gy, based on the information sent from the lateral acceleration sensor  67 . 
     &lt;Forward Information Detection Apparatus&gt; 
     The forward information detection apparatus  68  is an apparatus which detects information on a situation ahead of the own vehicle  100 . The forward information detection apparatus  68  includes, for example, at least one camera, at least one radar sensor such as at least one millimeter wave radar, at least one ultrasonic wave sensor such as at least one clearance sonar, and at least one laser radar such as at least one LiDAR. 
     The forward information detection apparatus  68  is electrically connected to the ECU  90 . The forward information detection apparatus  68  detects information on the situation ahead of the own vehicle  100 . The forward information detection apparatus  68  sends the detected information (forward information I_F) to the ECU  90 . 
     The ECU  90  can detect an object  200  ahead of the own vehicle  100 , based on the forward information I_F. Moreover, when the ECU  90  detects the object  200 , the ECU  90  can acquire an object distance D 200 , a relative moving speed dV, and a moving direction of the object  200 , based on the forward information I_F. The object distance D 200  is a distance between the object  200  and the own vehicle  100 . The relative moving speed dV is a relative moving speed of the own vehicle  100  with respect to the object  200 . In addition, the ECU  90  can recognize a left lane marking LML and a right lane marking LMR (see  FIG. 2A ) which define an own vehicle moving lane LN, based on the forward information I_F. The own vehicle moving lane LN is a moving lane of the own vehicle  100 . Otherwise, the ECU  90  can recognize an end of a road on which the own vehicle  100  moves, based on the forward information I_F. That is, the ECU  90  can recognize a road end, based on the forward information I_F. 
     Then, the ECU  90  acquires a yaw angle YA, based on the recognized left and right lane markings LML and LMR or the recognized road end. As shown in  FIG. 2B  and  FIG. 2C , the yaw angle YA is an angle between an own vehicle moving lane extending direction line LLN and an own vehicle longitudinal extending center line L 100 . The own vehicle moving lane extending direction line LLN is a line which represents an extending direction of the own vehicle moving lane LN. The own vehicle longitudinal extending center line L 100  is a line which extends through a center of a width of the own vehicle  100  in the longitudinal direction of the own vehicle  100 . 
     &lt;Summary of Operations of Vehicle Collision Avoidance Assist Apparatus&gt; 
     Next, a summary of operations of the vehicle collision avoidance assist apparatus  10  will be described. While the own vehicle  100  moves, the vehicle collision avoidance assist apparatus  10  determines, based on the forward information I_F, whether there is an object ahead of the own vehicle  100 . In this embodiment, the object is a vehicle, a person, a bicycle, or a guard rail. 
     When there is an object ahead of the own vehicle  100 , and a probability that the own vehicle  100  collides with the object has been increased to a high level, the vehicle collision avoidance assist apparatus  10  determines whether there is space at the side of the object where the own vehicle  100  can move and avoid the object. When there is the space, the vehicle collision avoidance assist apparatus  10  executes a steering avoidance control of steering the own vehicle  100  to avoid the object, using the space. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to execute an alerting process of informing the driver of the own vehicle  100  that the own vehicle  100  may collide with the object before the vehicle collision avoidance assist apparatus  10  starts an execution of the steering avoidance control. In this case, when the driver does not carry out an operation of avoiding the collision of the own vehicle  100  with the object such as an operation to the accelerator pedal  31 , an operation to the brake pedal  32 , and an operation to the steering wheel  33  even by executing the alerting process, the vehicle collision avoidance assist apparatus  10  executes a forcibly braking process of forcibly braking the own vehicle  100  to stop the own vehicle  100 . In this case, when the own vehicle  100  probably collides with the object even by executing the forcibly braking process, the vehicle collision avoidance assist apparatus  10  executes the steering avoidance control. 
     Further, the vehicle collision avoidance assist apparatus  10  executes a normal moving control when there is no object ahead of the own vehicle  100  or when there is the object ahead of the own vehicle  100  but the vehicle collision avoidance assist apparatus  10  predicts that the own vehicle  100  does not collide with the object. The normal moving control is a control of controlling the activation of the driving apparatus  21  to cause the driving apparatus  21  to output the driving force corresponding to the requested driving force PDreq when the requested driving force PDreq is greater than zero. In addition, the normal moving control is a control of controlling the activation of the braking apparatus  22  to cause the braking apparatus  22  to output the braking force corresponding to the requested braking force PBreq when the requested braking force PBreq is greater than zero. In addition, the normal moving control is a control of controlling the activation of the steering apparatus  23  to cause the steering apparatus  23  to output the steering torque corresponding to the assist steering torque TQas when the assist steering torque TQas is greater than zero. 
     &lt;Steering Avoidance Control&gt; 
     Next, the steering avoidance control will be described. 
     While the own vehicle  100  moves, the vehicle collision avoidance assist apparatus  10  determines, based on the forward information I_F, whether there is an object  200  in an own vehicle moving area A 100 . As shown in  FIG. 3A , the own vehicle moving area A 100  is an area which has (i) a center line corresponding to a moving route R 100  of the own vehicle  100  and (ii) a width equal to the width of the own vehicle  100 . The moving route R 100  of the own vehicle  100  is a route along which the own vehicle  100  predictively moves assuming that the own vehicle  100  moves with maintaining the current steering angle SA. 
     When the vehicle collision avoidance assist apparatus  10  determines that there is the object  200  in the own vehicle moving area A 100 , the vehicle collision avoidance assist apparatus  10  acquires an object distance D 200  and a relative moving speed dV. The object distance D 200  is a distance between the object  200  and the own vehicle  100 . The relative moving speed dV is a moving speed of the own vehicle  100  with respect to the object  200 . Then, the vehicle collision avoidance assist apparatus  10  calculates and acquires a predicted reaching time TTC by dividing the object distance D 200  by the relative moving speed dV (TTC=D 200 /dV). The predicted reaching time TTC is a time which the own vehicle  100  predictively takes to reach the object  200 . While the vehicle collision avoidance assist apparatus  10  determines that there is the object  200  in the own vehicle moving area A 100 , the vehicle collision avoidance assist apparatus  10  acquires the predicted reaching time TTC with a predetermined calculation cycle CYC. 
     When the relative moving speed dV is constant, the predicted reaching time TTC decreases as the object distance D 200  decreases. As shown in  FIG. 3B , when the own vehicle  100  approaches the object  200 , and the predicted reaching time TTC decreases to a predetermined time (this predetermined time will be hereinafter referred to as “predetermined predicted reaching time TTCth”), the vehicle collision avoidance assist apparatus  10  determines that a steering avoiding condition becomes satisfied. That is, when (i) the vehicle collision avoidance assist apparatus  10  acquires the predicted reaching time TTC as an index value which represents the probability that the own vehicle  100  collides with the object  200 , and z(ii) the index value becomes equal to or greater than a predetermined index value, the vehicle collision avoidance assist apparatus  10  determines that the probability that the own vehicle  100  collides with the object has increased to a high level. Thus, in this embodiment, the index value which represents the probability that the own vehicle  100  collides with the object  200  increases as the predicted reaching time TTC decreases. 
     When the steering avoiding condition becomes satisfied, the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control. When the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control, the vehicle collision avoidance assist apparatus  10  determines whether the driver operates the steering wheel  33  so as to cause the own vehicle  100  to pass by the object  200 . 
     When the vehicle collision avoidance assist apparatus  10  determines that the driver operates the steering wheel  33  so as to move the own vehicle  100  to avoid the object  200 , as shown in  FIG. 3C , the vehicle collision avoidance assist apparatus  10  sets a recommended avoidance route Rrec. The recommended avoidance route Rrec is a route recommended to move the own vehicle  100  to avoid the object  200 . 
     In this embodiment, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route to move the own vehicle  100  in the own vehicle moving lane LN and avoid the object  200 . In other words, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route to move the own vehicle  100  and avoid the object  200 , preventing the own vehicle  100  from moving out of the own vehicle moving lane LN. 
     Further, in order to avoid the collision of the own vehicle  100  with the object  200  by forcibly steering the own vehicle  100  to move the own vehicle  100  along the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  should set the recommended avoidance route Rrec, depending on the relative moving speed dV of the own vehicle  100  with respect to the object  200 . Accordingly, the vehicle collision avoidance assist apparatus  10  is configured to set the recommended avoidance route Rrec in consideration of the relative moving speed dV of the own vehicle  100  with respect to the object  200 . 
     Further, in this embodiment, the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, depending on the operation applied to the steering wheel  33  by the driver. In particular, when the driver rotates the steering wheel  33  clockwise, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route passing the right side of the object  200 . On the other hand, when the driver rotates the steering wheel  33  counterclockwise, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route passing the left side of the object  200 . 
     After the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  executes a process of steering the own vehicle  100  by increasing and decreasing the assist steering torque TQas, depending on the driver input torque TQdr so as to move the own vehicle  100  within a predetermined distance Dy from the recommended avoidance route Rrec. Hereinafter, this process of steering the own vehicle  100  will be referred to as “first avoiding steering process” or “assist steering process”. Thus, after the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  executes the first avoiding steering process of controlling the assist steering torque TQas so as to move the own vehicle  100  within the predetermined distance Dy from the recommended avoidance route Rrec. Thus, the first avoiding steering process is realized by controlling the assist steering torque TQas in consideration of the driver input torque TQdr. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to decelerate the own vehicle  100  by decreasing the driving force applied to the own vehicle  100  or limiting the driving force applied to the own vehicle  100  to a certain value or less or applying the braking force to the own vehicle  100  in addition to executing the first avoiding steering process. 
     On the other hand, when the vehicle collision avoidance assist apparatus  10  determines that the driver does not operate the steering wheel  33  to cause the own vehicle  100  to avoid the object  200  when (i) the steering avoiding condition becomes satisfied, and (ii) the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control, as shown in  FIG. 3D , the vehicle collision avoidance assist apparatus  10  sets a target avoidance route Rtgt to move the own vehicle  100  to avoid the object  200 . 
     In this embodiment, the vehicle collision avoidance assist apparatus  10  sets, as the target avoidance route Rtgt, a route to move the own vehicle  100  in the own vehicle moving lane LN and avoid the object  200 . In other words, the vehicle collision avoidance assist apparatus  10  sets, as the target avoidance route Rtgt, a route to move the own vehicle  100  and avoid the object  200 , preventing the own vehicle  100  from moving out of the own vehicle moving lane LN. 
     Further, in order to avoid the collision of the own vehicle  100  with the object  200  by forcibly steering the own vehicle  100  to move the own vehicle  100  along the target avoidance route Rtgt, the vehicle collision avoidance assist apparatus  10  should set the target avoidance route Rtgt, depending on the relative moving speed dV of the own vehicle  100  with respect to the object  200 . Accordingly, the vehicle collision avoidance assist apparatus  10  is configured to set the target avoidance route Rtgt in consideration of the relative moving speed dV of the own vehicle  100  with respect to the object  200 . 
     After the vehicle collision avoidance assist apparatus  10  sets the target avoidance route Rtgt, the vehicle collision avoidance assist apparatus  10  executes a process of steering the own vehicle  100  by controlling the assist steering torque TQas to move the own vehicle  100  along the target avoidance route Rtgt. Hereinafter, this process of steering the own vehicle  100  will be referred to as “second avoiding steering process” or “autonomous steering process”. Thus, the second avoiding steering process is realized by controlling the assist steering torque TQas without considering the driver input torque TQdr. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to decelerate the own vehicle  100  by decreasing the driving force applied to the own vehicle  100  or limiting the driving force applied to the own vehicle  100  to a certain value or less or applying the braking force to the own vehicle  100  in addition to executing the second avoiding steering process. 
     When (i) the avoidance route R (i.e., the recommended avoidance route Rrec or the target avoidance route Rtgt) is set as shown in  FIG. 4A , and (ii) an execution of the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) is started, the own vehicle  100  is steered to move along the avoidance route R as shown in  FIG. 4B , and avoids the collision with the object  200  as shown in  FIG. 4C . 
     It should be noted that the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) when (i) the width of the own vehicle moving lane LN is narrow and thus, there is no space to move the own vehicle  100  to avoid the object  200  at the side of the object  200  and thus, (ii) the vehicle collision avoidance assist apparatus  10  cannot set the recommended avoidance route Rrec or the target avoidance route Rtgt. Also, the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) when (i) the vehicle collision avoidance assist apparatus  10  does not recognize the left lane marking LML at the left side of the own vehicle  100  or the right lane marking LMR at the right side of the own vehicle  100  and thus, (ii) the vehicle collision avoidance assist apparatus  10  cannot set the recommended avoidance route Rrec or the target avoidance route Rtgt. That is, when a forbidding condition that the recommended avoidance route Rrec or the target avoidance route Rtgt cannot be set, is satisfied, the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process. 
     It should be noted that one or more of conditions C 1  to C 21  below may be used as the forbidding condition. 
     A condition C 1  is a condition that the vehicle collision avoidance assist apparatus  10  cannot realize the avoiding steering process (the first avoiding steering process of the second avoiding steering process) due to a fact that devices such as the steering apparatus  23  used to realize the avoiding steering process are malfunctioned. 
     A condition C 2  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute an autonomous brake control (PCS), the vehicle collision avoidance assist apparatus  10  cannot realize the autonomous brake control due to a fact that devices such as the braking apparatus  22  used to realize the autonomous brake control are malfunctioned. The autonomous brake control is a control of stopping the own vehicle  100  by forcibly braking the own vehicle  100  before the own vehicle  100  collides with the object ahead of the own vehicle  100  when the probability that the own vehicle  100  collides with the object ahead of the own vehicle  100  has increased to a high level. 
     A condition C 3  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute a sideslip prevention control (VSC), the vehicle collision avoidance assist apparatus  10  cannot realize the sideslip prevention control due to a fact that devices such as the braking apparatus  22  used to realize the sideslip prevention control are malfunctioned. The sideslip prevention control is, for example, a control of stabilizing a moving behavior of the own vehicle  100  by adjusting the driving force PD applied to the own vehicle  100  or individually adjusting the braking forces PB applied to wheels of the own vehicle  100 , respectively when the moving behavior of the own vehicle  100  becomes unstable due to steering the own vehicle  100 . 
     A condition C 4  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute the autonomous brake control (PCS), the vehicle collision avoidance assist apparatus  10  can stop the own vehicle  100  by the autonomous brake control before the own vehicle  100  collides with the object  200 . 
     A condition C 5  is a condition that when (i) the vehicle collision avoidance assist apparatus  10  is configured to execute the autonomous brake control (PCS), and (ii) the vehicle collision avoidance assist apparatus  10  starts executing the autonomous brake control and then, terminates executing the autonomous brake control, a time elapsing since the vehicle collision avoidance assist apparatus  10  terminates executing the autonomous brake control is equal to or shorter than a predetermined time. 
     A condition C 6  is a condition that when the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control and then, the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control, a time elapsing since the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control is equal to or shorter than a predetermined time. 
     A condition C 7  is a condition that the vehicle collision avoidance assist apparatus  10  activates or blinks turn signals of the own vehicle  100 . 
     A condition C 8  is a condition that when (i) the object  200  is a preceding vehicle, and (ii) the recommended avoidance route Rrec or the target avoidance route Rtgt is a route passing at the left side of the preceding vehicle, left turn signals of the preceding vehicle are activated or blinked. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the left turn signals of the preceding vehicle are activated or blinked. It should be noted that the preceding vehicle is a vehicle which moves ahead of the own vehicle  100  in the own vehicle moving lane LN or the moving lane of the own vehicle  100  in the same direction as the moving direction of the own vehicle  100 . 
     A condition C 9  is a condition that when (i) the object  200  is the preceding vehicle, and (ii) the recommended avoidance route Rrec or the target avoidance route Rtgt is a route passing at the right side of the preceding vehicle, right turn signals of the preceding vehicle are activated or blinked. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the right turn signals of the preceding vehicle are activated or blinked. 
     A condition C 10  is a condition that the accelerator pedal operation amount AP is equal to or greater than a predetermined accelerator pedal operation amount APth. 
     A condition C 11  is a condition that the brake pedal operation amount BP is equal to or greater than a predetermined brake pedal operation amount BPth. 
     A condition C 12  is a condition that the vehicle moving speed V 100  of the own vehicle  100  is not within a predetermined range Rv. 
     A condition C 13  is a condition that the relative moving speed dV of the object  200  with respect to the own vehicle  100  is not within a predetermined range Rdv. 
     A condition C 14  is a condition that the lateral acceleration Gy is equal to or greater than a predetermined lateral acceleration Gy_th. 
     A condition C 15  is a condition that the longitudinal acceleration Gx is a positive value, and an absolute value of the longitudinal acceleration Gx is equal to or greater than a predetermined value Gx_th. 
     A condition C 16  is a condition that the longitudinal acceleration Gx is a negative value, and the absolute value of the longitudinal acceleration Gx is equal to or greater than the predetermined value Gx_th. 
     A condition C 17  is a condition that the own vehicle  100  moves along a curving road. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the own vehicle  100  moves along the curving road. 
     A condition C 18  is a condition that a lane-markings distance is equal to or longer than a predetermined distance. The lane-markings distance is a distance between the left lane marking LML at the left side of the own vehicle  100  and the right lane marking LMR at the right side of the own vehicle  100 . The vehicle collision avoidance assist apparatus  10  can acquire the lane-markings distance, based on the forward information I_F. 
     A condition C 19  is a condition that the recommended avoidance route Rrec or the target avoidance route Rtgt crosses a longitudinally-extending center line of the object  200 . The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the recommended avoidance route Rrec or the target avoidance route Rtgt crosses the longitudinally-extending center line of the object  200 . 
     A condition C 20  is a condition that the object  200  moves, crossing the recommended avoidance route Rrec or the target avoidance route Rtgt. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the object  200  moves, crossing the recommended avoidance route Rrec or the target avoidance route Rtgt. 
     A condition C 21  is a condition that the vehicle collision avoidance assist apparatus  10  can set the recommended avoidance route Rrec or the target avoidance route Rtgt but the vehicle collision avoidance assist apparatus  10  predicts that the vehicle collision avoidance assist apparatus  10  cannot move the own vehicle  100  along the recommended avoidance route Rrec or the target avoidance route Rtgt. 
     &lt;Termination of Execution of Steering Avoidance Control&gt; 
     After the vehicle collision avoidance assist apparatus  10  starts executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the vehicle collision avoidance assist apparatus  10  monitors whether a terminating condition becomes satisfied. The terminating condition is a condition that an absolute value of the yaw angle YA becomes equal to or smaller than a predetermined yaw angle YAth. The vehicle collision avoidance assist apparatus  10  continues executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) as far as the terminating condition is not satisfied. On the other hand, when the terminating condition becomes satisfied, the vehicle collision avoidance assist apparatus  10  terminates executing the avoiding steering process or the steering avoidance control. 
     It should be noted that when the vehicle collision avoidance assist apparatus  10  is configured to execute the steering avoidance control and brake and stop the own vehicle  100 , the vehicle collision avoidance assist apparatus  10  may be configured to terminate executing the steering avoidance control or the avoiding steering process when the own vehicle  100  stops. 
     &lt;Stop of Execution of Steering Avoidance Control&gt; 
     The object  200  with which the steering avoidance control avoids the collision of the own vehicle  100 , may be an object such as the preceding vehicle which moves in the same direction as the moving direction of the own vehicle  100 . Hereinafter, the object  200  with which the steering avoidance control avoids the collision of the own vehicle  100 , will be referred to as “target object  200   tgt ”. Further, the target object  200   tgt  which moves in the same direction as the moving direction of the own vehicle  100 , will be referred to as “target moving object  200 Mtgt”. In this case, if (i) the vehicle collision avoidance assist apparatus  10  sets the avoidance route R (i.e., the recommended avoidance route Rrec or the target avoidance route Rtgt) as shown in  FIG. 5A  and starts executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), and then (ii) the target moving object  200 Mtgt is decelerated, the own vehicle  100  may rapidly approach the target moving object  200 Mtgt, and the avoidance route R becomes close to or crosses the target moving object  200 Mtgt. For example, as shown in  FIG. 5B , if the avoiding steering process continues being executed when the own vehicle  100  rapidly approaches the target moving object  200 Mtgt, and the avoidance route R becomes close to or crosses the target moving object  200 Mtgt, the own vehicle  100  may collides with the target moving object  200 Mtgt. 
     Accordingly, when the target object  200   tgt  is a moving object  200 M or the target moving object  200 Mtgt, the vehicle collision avoidance assist apparatus  10  acquires a deceleration GxM of the target moving object  200 Mtgt, based on the forward information I_F after the vehicle collision avoidance assist apparatus  10  starts executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process). Then, the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control when the deceleration GxM becomes equal to or greater than a predetermined deceleration GxMth. 
     Thus, if the deceleration GxM of the target moving object  200 Mtgt does not becomes equal to or greater than the predetermined deceleration GxMth before the terminating condition becomes satisfied after the vehicle collision avoidance assist apparatus  10  starts executing the avoiding steering process, the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control when the terminating condition becomes satisfied as shown in  FIG. 6 . 
     In an example shown in  FIG. 6 , at a point of time t 60 , the steering avoiding condition becomes satisfied, and the execution of the steering avoidance control is started. Then, at a point of time t 61 , the deceleration GxM of the target moving object  200 Mtgt starts to increase. Then, at a point of time t 62 , the deceleration GxM of the target moving object  200 Mtgt becomes zero. However, the deceleration GxM of the target moving object  200 Mtgt does not become equal to or greater than the predetermined deceleration GxMth. Thus, the execution of the steering avoidance control is continued. Then, at a point of time t 63 , the terminating condition becomes satisfied. Thus, the execution of the steering avoidance control is terminated. 
     On the other hand, when the deceleration GxM of the target moving object  200 Mtgt becomes equal to or greater than the predetermined deceleration GxMth before the terminating condition becomes satisfied, the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control as shown in  FIG. 7 . That is, when a stopping condition that the deceleration GxM of the target moving object  200 Mtgt becomes equal to or greater than the predetermined deceleration GxMth before the terminating condition becomes satisfied, becomes satisfied, the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control. 
     In an example shown in  FIG. 7 , at a point of time t 70 , the steering avoiding condition becomes satisfied. Thus, the execution of the steering avoidance control is started. Then, at a point of time t 71 , the deceleration GxM of the target moving object  200 Mtgt becomes equal to or greater than the predetermined deceleration GxMth. Thus, the stopping condition becomes satisfied. Thus, the execution of the steering avoidance control is stopped. 
     As described above, when the moving object  200 M with which the steering avoidance control avoids the collision of the own vehicle  100 , is decelerated, i.e., the target moving object  200 Mtgt is decelerated, the own vehicle  100  may rapidly approach the target moving object  200 Mtgt, and the avoidance route R may become close to or cross the target moving object  200 Mtgt. If the execution of the steering avoidance control is continued after the own vehicle  100  rapidly approaches the target moving object  200 Mtgt, and the avoidance route R becomes close to or cross the target moving object  200 Mtgt, the own vehicle  100  may collide with the target moving object  200 Mtgt. According to the vehicle collision avoidance assist apparatus  10 , the execution of the steering avoidance control is stopped when (i) the target moving object  200 Mtgt is decelerated while the steering avoidance control is being executed, and (ii) the deceleration GxM of the target moving object  200 Mtgt becomes equal to or greater than the predetermined deceleration GxMth. Thus, the own vehicle  100  can be prevented from colliding with the target moving object  200 Mtgt due to the deceleration of the target moving object  200 Mtgt. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to stop executing the steering avoidance control when the driver input torque TQdr becomes equal to or greater than a relatively great predetermined torque TQth while the vehicle collision avoidance assist apparatus  10  executes the steering avoidance control. 
     &lt;Specific Operations of Vehicle Collision Avoidance Assist Apparatus&gt; 
     Next, specific operations of the vehicle collision avoidance assist apparatus  10  will be described. The CPU of the ECU  90  of the vehicle collision avoidance assist apparatus  10  is configured or programmed to execute a routine shown in  FIG. 8  each time a predetermined time elapses. Thus, at a predetermined timing, the CPU starts executing a process from a step  800  of the routine shown in  FIG. 8  and proceeds with the process to a step  805  to determine whether a value of a steering avoiding condition flag Xst is “1”. The value of the steering avoiding condition flag Xst is set to “1” when the steering avoiding condition becomes satisfied. 
     When the CPU determines “Yes” at the step  805 , the CPU proceeds with the process to a step  810  to determine whether the driver input torque TQdr is greater than zero. When the CPU determines “Yes” at the step  810 , the CPU proceeds with the process to a step  815  to set the recommended avoidance route Rrec. Then, the CPU proceeds with the process to a step  820  to determine whether the CPU has set the recommended avoidance route Rrec. 
     When the CPU determines “Yes” at the step  820 , the CPU proceeds with the process to a step  825  to start executing the first avoiding steering process. Then, the CPU proceeds with the process to a step  845 . On the other hand, when the CPU determines “No” at the step  820 , the CPU proceeds with the process directly to the step  845 . In this case, the execution of the first avoiding steering process is not started. 
     Further, when the CPU determines “No” at the step  810 , the CPU proceeds with the process to a step  830  to set the target avoidance route Rtgt. Then, the CPU proceeds with the process to a step  835  to determine whether the CPU has set the target avoidance route Rtgt. When the CPU determines “Yes” at the step  835 , the CPU proceeds with the process to a step  840  to start executing the second avoiding steering process. Then, the CPU proceeds with the process to the step  845 . On the other hand, when the CPU determines “No” at the step  835 , the CPU proceeds with the process directly to the step  845 . In this case, the execution of the second avoiding steering process is not started. 
     When the CPU proceeds with the process to the step  845 , the CPU sets the value of the steering avoiding condition flag Xst to “0”. Then, the CPU proceeds with the process to a step  850 . 
     Further, when the CPU determines “No” at the step  805 , the CPU proceeds with the process directly to the step  850 . 
     When the CPU proceeds with the process to the step  850 , the CPU determines whether the stopping condition becomes satisfied. When the CPU determines “Yes” at the step  850 , the CPU proceeds with the process to a step  855 . At the step  855 , when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU stops executing the steering avoidance control by stopping executing the avoiding steering process. Then, the CPU proceeds with the process to a step  860 . On the other hand, when the CPU determines “No” at the step  850 , the CPU proceeds with the process directly to the step  860 . At this time, when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU continues executing the avoiding steering process. 
     When the CPU proceeds with the process to the step  860 , the CPU determines whether the terminating condition becomes satisfied. When the CPU determines “Yes” at the step  860 , the CPU proceeds with the process to a step  865 . At the step  865 , when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU terminates executing the steering avoidance control by terminating executing the avoiding steering process. Then, the CPU proceeds with the process to a step  895  to terminate executing the process of this routine once. On the other hand, when the CPU determines “No” at the step  860 , the CPU proceeds with the process directly to the step  895  to terminate executing the process of this routine once. At this time, when the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) is executed, the execution of the avoiding steering process is continued. 
     The specific operations of the vehicle collision avoidance assist apparatus  10  have been described. 
     It should be noted that the invention is not limited to the aforementioned embodiments, and various modifications can be employed within the scope of the invention.