Driver assistance device and method of operating the same

Abstract

The present application relates to a driver assistance device and an operation method thereof, the driver assistance device including: a processing portion; and a storage portion containing a command executed by the processing portion, when a vehicle changes a lane from a travel lane to a target lane, the processing portion judges a collision possibility of the vehicle with other vehicles in the target lane, when there is no collision possibility of the vehicle with the other vehicles, calculates an expected deceleration amount of the vehicle with respect to a target vehicle in the target lane, and compares with a deceleration standard, and determines whether to execute a lane change assistance control based on a comparison result.

Description

TECHNICAL FIELD

[0001] The present application relates to a driver assistance device and an operation method thereof. BACKGROUND

[0002] A lane change assist system determines whether there is a possibility of collision with a vehicle in front and / or behind of a target lane to be changed and gives a warning, and when the possibility of collision is low, the lane change assist system actively assists lane change by steering control or the like. The lane change assist system determines the collision risk of a vehicle with a vehicle in front and / or behind of the target lane using a time to collision (TTC) required for the vehicle to collide with the vehicle in front and / or behind and a deceleration distance at a current time point or the like. That is, the lane change assist system in the related art prohibits execution of lane change or does not operate the lane change assist function by determining whether there is a collision.

[0003] However, even when there is no collision while the lane change assist function is activated, sudden deceleration can occur when changing lanes while decelerating, and thus the driver can feel uncomfortable. SUMMARY

[0004] (I) PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] An object of the present application is to provide a driver assistance device and an operation method thereof that controls an operation timing point of a lane change assist function based on an expected deceleration amount of a vehicle when changing lanes.

[0006] (II) TECHNICAL SOLUTION

[0007] To solve the above technical problem, a driver assistance device according to one embodiment of the present application is characterized by including: a processing portion; and a storage portion containing a command executed by the processing portion, when a vehicle changes lanes from a travel lane to a target lane, the processing portion determines a collision possibility of the vehicle with another vehicle in the target lane, when there is no collision possibility of the vehicle with the another vehicle, calculates an expected deceleration amount of the vehicle with respect to a target vehicle in the target lane to compare with a deceleration standard, and determines whether to execute lane change assist control based on a comparison result.

[0008] The present application is characterized in that the processing portion enables a lane change assist function based on a user input.

[0009] The present application is characterized in that the user input is a signal generated according to a switch operation to enable the lane change assist function.

[0010] The processing section calculates a first required acceleration of the vehicle with respect to a first target vehicle in the target lane, and a second required acceleration of the vehicle with respect to a second target vehicle in the travel lane, and then calculates the expected deceleration amount based on the smaller of the first required acceleration and the second required acceleration.

[0011] The processing section calculates a required acceleration of a distance error of a preset target inter-vehicle distance between the vehicle and the first target vehicle, and a required acceleration of a speed error of the vehicle and the first target vehicle, and then calculates the first required acceleration using the required acceleration of the distance error and the required acceleration of the speed error.

[0012] The processing section limits the first required acceleration based on a time required for a collision of the vehicle with respect to the first target vehicle.

[0013] The processing section calculates the deceleration standard based on a speed of the vehicle.

[0014] The deceleration standard is set to decrease as the speed of the vehicle increases.

[0015] The processing section determines to execute the lane change assist control when the expected deceleration amount is below the deceleration standard.

[0016] The processing section determines not to execute the lane change assist control when the expected deceleration amount exceeds the deceleration standard.

[0017] On the other hand, an operation method of a driver assist device according to an embodiment of the present application includes the steps of: judging a possibility of a collision of a vehicle with other vehicles in a target lane when the vehicle changes lanes from a travel lane to the target lane; calculating an expected deceleration amount of the vehicle with respect to a target vehicle in the target lane when there is no possibility of a collision of the vehicle with the other vehicles; and comparing the expected deceleration amount with a deceleration standard to determine whether to execute a lane change assist control.

[0018] The step of judging the possibility of the collision further includes the step of enabling a lane change assist function according to a user input.

[0019] The user input is a signal generated according to a switch operation of enabling the lane change assist function.

[0020] The present invention is characterized in that the step of calculating the expected deceleration includes the following steps: calculating a first required acceleration of the vehicle relative to a first target vehicle in the target lane; calculating a second required acceleration of the vehicle relative to a second target vehicle in the driving lane; and calculating the expected deceleration based on the smaller of the first required acceleration and the second required acceleration.

[0021] The present invention is characterized in that the step of calculating the first required acceleration includes the following steps: calculating the required acceleration due to the distance error between the actual distance between the vehicle and the first target vehicle and the preset target vehicle distance; calculating the required acceleration due to the speed error between the vehicle and the first target vehicle; and calculating the first required acceleration using the required acceleration due to the distance error and the required acceleration due to the speed error.

[0022] The present invention is characterized in that the step of calculating the first required acceleration further includes the step of limiting the first required acceleration based on the time required for the collision between the vehicle and the first target vehicle.

[0023] The present invention is characterized in that the step of calculating the expected deceleration amount further includes the step of calculating the deceleration standard based on the speed of the vehicle.

[0024] The present invention is characterized in that the deceleration standard is set to decrease as the vehicle speed increases.

[0025] The present invention is characterized in that the step of determining whether to perform the lane change assist control includes the step of determining to perform lane change assist control when the expected deceleration amount is below the deceleration standard.

[0026] The present invention is characterized in that the step of determining whether to perform the lane change assist control further includes the step of determining not to perform lane change assist control when the expected deceleration amount exceeds the deceleration standard.

[0027] (III) Beneficial Effects

[0028] According to the present invention, the timing of activating the lane change assist function is controlled based on the expected deceleration of the vehicle when changing lanes, so that sudden deceleration is not caused when changing lanes, thereby avoiding discomfort caused by sudden deceleration for the driver. Attached Figure Description

[0029] Figure 1 This is a structural block diagram of a driver assistance device according to an embodiment of the present invention.

[0030] Figure 2 This is a diagram used to illustrate the calculation of the expected deceleration in relation to the present invention.

[0031] Figure 3 is a graph showing deceleration limit based on time-to-collision related to the present application.

[0032] Figure 4 is a graph showing deceleration criteria based on vehicle speed related to the present application.

[0033] Figure 5 is a flowchart showing an operation method of a driver assist device according to an embodiment of the present application.

[0034] Figure 6 is a block diagram showing a computing system that executes an operation method according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] Hereinafter, some embodiments of the present application will be described in detail with reference to the exemplary drawings. When assigning reference numerals to the components in the drawings, the same components are designated by the same reference numerals even if they are shown in different drawings. Further, in describing the embodiments of the present application, when it is determined that the detailed description of related well-known structures or functions will make the understanding of the embodiments of the present application more difficult, the detailed description thereof will be omitted.

[0036] In describing the components of the embodiments of the present application, the terms first, second, A, B, (a), (b), and the like can be used. These terms are used only to distinguish one component from another component, and the terms do not limit the properties, the order, or the sequence of the corresponding components. Unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meanings as those generally understood by one of ordinary skill in the art to which the present application pertains. The terms such as those defined in a generally used dictionary should be interpreted as having meanings consistent with the meanings in the context of the relevant technology, and should not be interpreted as ideally or excessively formal meanings unless otherwise defined.

[0037] Figure 1 is a structural block diagram of a driver assist device according to an embodiment of the present application, Figure 2 is a graph for explaining calculation of an expected deceleration amount related to the present application, Figure 3 is a graph showing deceleration limit based on time-to-collision related to the present application, Figure 4 is a graph showing deceleration criteria based on vehicle speed related to the present application.

[0038] Referring to Figure 1 , the driver assist device 100 includes a detection section 110, a user input section 120, a storage section 130, and a processing section 140.

[0039] The detection unit 110 recognizes (detects) the position and / or speed of a moving object and / or a stationary object located around the vehicle, etc. by various sensors mounted on the vehicle. In addition, the detection unit 110 can also detect the position and curvature of a lane line, etc. by the sensors. Among them, the sensors include a light radar (LiDAR), a radar, a camera (image sensor), an ultrasonic sensor, a speed sensor, etc.

[0040] The user input unit 120 generates data based on the user's operation. For example, the user input unit 120 generates a signal based on the user's input to turn on or off the direction indicator. In addition, the user input unit 120 generates a signal based on the user's input to enable (ON) or disable (OFF) the lane change assist function. The user input unit 120 can be provided on a steering wheel, a dashboard, a center fascia, a door trim, etc., and can be formed as a keyboard, a keypad, a button, a switch, a touchpad, a touch screen, etc.

[0041] The storage unit 130 can store a program for the operation of the processing unit 140, and can temporarily store data input to and / or output from the processing unit 140. The storage unit 130 can be at least one of the following storage media (recording media), such as a flash memory, a hard disk, a secure digital card (SD card), a random access memory (RAM), a static random access memory (SRAM), a read only memory (ROM), a programmable read only memory (PROM), an electrically erasable and programmable ROM (EEPROM), an erasable and programmable ROM (EPROM), a register, a removable disk, a web storage, etc.

[0042] The processing section 140 controls the overall operation of the driver assist device 100. The processing section 140 can be at least one of an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a Central Processing unit (CPU), a microcontroller, and a microprocessor.

[0043] The processing section 140 performs functions such as selecting a target, determining a collision, calculating an expected deceleration amount, and determining a lane change assist control. In addition, the processing section 140 can exchange data with the lane change assist controller 200 through a vehicle network (IVN). The vehicle network can be a Controller Area Network (CAN), a Media Oriented Systems Transport (MOST) network, a Local Interconnect Network (LIN), an ethernet, and / or a Flexray, etc. Although not shown in the drawing, the lane change assist controller 200 can include a communication module, a user input module, an output module, a processor, and a memory.

[0044] When the processing section 140 receives a lane change request, the lane change assist function is activated. The processing section 140 receives a user input for executing the lane change assist function from the user input section 120. For example, when the user, i.e., the driver, operates a direction indicator (turns on or off a switch for turning on or off a direction indicator light) to turn on the direction indicator light, the processing section 140 activates (turns on) the lane change assist function in the lane change assist controller 200. On the other hand, when the user operates a lane change assist function activation switch to activate the lane change function, the processing section 140 requests the lane change assist controller 200 to activate the lane change assist function. In the present embodiment, the lane change request is received from the user input section 120, but is not limited thereto, and can be received from other electronic control devices (not shown) installed in the vehicle or from an external terminal.

[0045] The processing portion 140 identifies the position and speed of the surrounding vehicles and the like by the detection portion 110. At this time, the processing portion 140 identifies the object (e.g., preceding vehicle and / or following vehicle) of each lane. For example, the processing portion 140 identifies (detects) the preceding vehicle (preceding vehicle) and / or following vehicle traveling on the target lane to be entered by changing the lane by the detection portion 110. In addition, the processing portion 140 can identify the preceding vehicle and / or following vehicle in the travel lane in which the vehicle is traveling by the detection portion 110.

[0046] The processing portion 140 distinguishes the object (e.g., preceding vehicle) of each lane by the detection portion 110 to select the target vehicle(s) when starting the lane change assist function. The processing portion 140 selects the preceding vehicle in the target lane to be entered by changing the lane by the vehicle as the first target vehicle. In addition, the processing portion 140 can select the preceding vehicle in the travel lane in which the vehicle is traveling as the second target vehicle.

[0047] When changing the lane to the target lane, the processing portion 140 determines whether there is a possibility of collision between the vehicle and the preceding vehicle and / or following vehicle of the target lane. The processing portion 140 calculates the time required for the vehicle to collide with the preceding vehicle and / or following vehicle, that is, the Time To Collision (TTC), and determines that there is a possibility of collision when the calculated TTC is less than the standard TTC stored in advance in the storage portion 130. On the other hand, when the calculated TTC is the standard TTC or more, the processing portion 140 determines that there is no possibility of collision.

[0048] When there is no possibility of collision between the vehicle and the preceding vehicle and / or following vehicle of the target lane, the processing portion 140 calculates the expected deceleration of the vehicle with respect to the first target vehicle. The processing portion 140 calculates the expected deceleration of the vehicle with respect to the second target vehicle in the travel lane at the same time as calculating the expected deceleration of the vehicle with respect to the first target vehicle. The processing portion 140 simultaneously calculates the required acceleration with respect to the preceding vehicle of the target lane, that is, the first target vehicle (first required acceleration) and the required acceleration with respect to the preceding vehicle of the travel lane, that is, the second target vehicle (second required acceleration), and the smaller of the calculated first required acceleration and second required acceleration as the final required acceleration (= MIN(first required acceleration, second required acceleration)). The processing portion 140 calculates the expected deceleration amount based on the final required acceleration.

[0049] Hereinafter, the processing of the processing portion 140 will be described with reference to Figure 2 and Figure 3Further specifically described is a method of calculating an expected deceleration amount of a vehicle with respect to a preceding vehicle in a target lane when the preceding vehicle is selected as a target vehicle (first target vehicle).

[0050] The processing portion 140 calculates a required acceleration of the vehicle 100A based on a distance difference (distance error) of the target inter-vehicle distance D target and an actual distance (measured distance) D between the vehicle 100A and the first target vehicle 100B, i.e., a distance error required acceleration (ReqAccelDis). The distance error required acceleration (ReqAccelDis) can be expressed as the following [Math. 1].

[0051] [Math. 1]

[0052] ReqAccelDis = K D x (D target - D)

[0053] wherein the target inter-vehicle distance D target is a distance between vehicles finally maintained when a travel speed is constant, and is set by a user (i.e., a driver). K D is an acceleration / deceleration control gain of a distance error, which is set in advance by a system designer.

[0054] Next, the processing portion 140 calculates a required acceleration of the vehicle 100A based on a speed difference, i.e., a speed error, of a speed V S of the vehicle 100A and a speed V P of the first target vehicle 100B. The processing portion 140 calculates the speed error required acceleration (ReqAccelSpd) using [Math. 2].

[0055] [Math. 2]

[0056] ReqAccelSpd = K S x (V P - V S )

[0057] wherein K S is an acceleration / deceleration control gain of a speed error, and is set in advance by a system designer as K D .

[0058] The processing portion 140 calculates the required acceleration (ReqAccel) with respect to the first target vehicle 100B in the target lane by adding the required acceleration of the distance error (ReqAccelDis) and the required acceleration of the speed error (ReqAccelSpd). The processing portion 140 calculates the expected deceleration amount of the vehicle with respect to the first target vehicle 100B on the basis of the required acceleration (ReqAccel) with respect to the first target vehicle 100B. As shown in Figure 3 The processing portion 140 can limit the required acceleration (ReqAccel) of the vehicle 100A with respect to the first target vehicle 100B on the basis of the TTC of the vehicle 100A with respect to the first target vehicle 100B. The deceleration of the vehicle 100A with respect to the first target vehicle 100B, that is, the required acceleration (ReqAccel) with respect to the first target vehicle 100B can be defined as the following [Mathematical Formula 3].

[0059] [Mathematical Formula 3]

[0060] ReqAccel = Lim (ReqAccelDis + ReqAccelSpd)

[0061] In the present embodiment, only the required acceleration with respect to the preceding vehicle in the target lane is described, but the required acceleration with respect to the preceding vehicle in the travel lane can be calculated by the same method as the method of calculating the required acceleration with respect to the preceding vehicle in the target lane.

[0062] For example, the processing portion 140 calculates the required acceleration of the distance error on the basis of the actual distance and the target inter-vehicle distance D target between the vehicle 100A and the preceding vehicle in the travel lane, that is, the second target vehicle 100C, and the speed difference (= V P0 - V S ) between the vehicle 100A and the second target vehicle 100C. The processing portion 140 adds the sum of the two calculated required accelerations as the required acceleration with respect to the preceding vehicle in the travel lane. At this time, the processing portion 140 can limit the required acceleration with respect to the preceding vehicle in the travel lane on the basis of the TTC of the vehicle 100A with respect to the second target vehicle 100C.

[0063] In addition, the processing portion 140 can calculate a deceleration criterion for judging the start timing of the lane change assist function. The deceleration criterion is a deceleration at which the ride comfort when changing the lane is good, and the driver does not feel uncomfortable. As shown in Figure 4As shown, the deceleration criterion can be set (calculated) to decrease as the speed of the vehicle (i.e., the vehicle speed) increases. The deceleration criterion based on the vehicle speed can be pre-stored in the storage section 130 in the form of a lookup table.

[0064] The processing section 140 compares the expected deceleration amount with the deceleration criterion, and determines whether to execute the lane change assist control (i.e., whether to activate the lane change assist function) based on the comparison result. When the expected deceleration amount is below the deceleration criterion, the processing section 140 determines to execute the lane change assist control. On the other hand, when the expected deceleration amount exceeds the deceleration criterion, the processing section 140 determines not to execute the lane change assist control.

[0065] As described above, the processing section 140 determines not to execute the lane change assist when there is a possibility of collision between the vehicle and the preceding vehicle and / or the following vehicle in the target lane.

[0066] As described above, the processing section 140 determines whether to execute (activate) the lane change assist function, i.e., the timing of activation of the lane change assist function, based on the collision possibility of the vehicle and the expected deceleration amount when changing the lane.

[0067] Figure 5 is a flowchart showing an operation method of a driver assist device according to one embodiment of the present application.

[0068] Referring to Figure 5 The processing section 140 activates the lane change assist function upon receiving the lane change request (S110). When the driver operates the direction indicator or an additional switch to activate the lane change assist function, the processing section 140 controls the lane change assist controller 200 to activate the lane change assist function upon receiving the user input based on the driver's operation. The processing section 140 selects a preceding vehicle in the target lane to be entered by changing the lane as the first target vehicle. In addition, the processing section 140 can select a preceding vehicle in the travel lane of the vehicle as the second target vehicle.

[0069] The processing section 140 determines whether there is a possibility of collision between the vehicle and other vehicles in the target lane (S120). The processing section 140 calculates the TTC of the vehicle with respect to other vehicles in the target lane, such as the preceding vehicle and / or the following vehicle. The processing section 140 determines (judges) the possibility of collision based on the calculated TTC. In other words, when the calculated TTC is less than the pre-stored standard TTC, the processing section 140 judges that there is a possibility of collision, and when the calculated TTC is the standard TTC or more, the processing section 140 judges that there is no possibility of collision.

[0070] When there is no possibility of collision, the processing portion 140 calculates an expected deceleration amount and a deceleration criterion (S130). The processing portion 140 calculates the deceleration criterion based on the speed of the vehicle (vehicle speed). In addition, when the preceding vehicle in the target lane is selected as the target vehicle, the processing portion 140 calculates the expected deceleration amount of the vehicle. In other words, the processing portion 140 calculates the deceleration with respect to the first target vehicle in the target lane (first required acceleration) and the deceleration with respect to the second target vehicle in the travel lane (second required acceleration), and then calculates the expected deceleration amount according to the smaller required deceleration of the calculated first required acceleration and second required acceleration. When each required acceleration is calculated, the processing portion 140 calculates the required acceleration based on the target vehicle distance and the distance difference of the actual distance between the vehicle and the target vehicle and the speed difference between the vehicle and the target vehicle. In addition, the processing portion 140 limits the required acceleration with respect to the target vehicle based on the TTC of the vehicle with respect to the target vehicle.

[0071] The processing portion 140 compares the calculated expected deceleration amount with the deceleration criterion (S140). The processing portion 140 determines whether the expected deceleration amount is below the deceleration criterion.

[0072] When the expected deceleration amount is below the deceleration criterion, the processing portion 140 determines to execute the lane change assist control (S150). The processing portion 140 requests the lane change assist controller 200 for the lane change assist control to cause the lane change assist controller 200 to execute the lane change assist.

[0073] When the expected deceleration amount exceeds the deceleration criterion, the processing portion 140 determines not to execute the lane change assist control (S160). The processing portion 140 limits the operation of the lane change assist controller 200, so that the lane change assist control is not executed.

[0074] Figure 6 is a block diagram illustrating a computing system that executes an operation method according to one embodiment of the present application.

[0075] Referring to Figure 6 , the computing system 1000 can include at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, a storage 1600, and a network interface 1700 connected through a bus 1200.

[0076] The processor 1100 can be a central processing unit (CPU) or a semiconductor device that processes commands stored in the memory 1300 and / or the storage 1600. The memory 1300 and the storage 1600 can include various types of volatile or non-volatile storage media. For example, the memory 1300 can include read-only memory (ROM) 1310 and random access memory (RAM) 1320.

[0077] Accordingly, the steps of the methods or algorithms described in connection with the embodiments disclosed in the present application can be directly implemented by a hardware implemented, a software module executed by the processor 1100, or a combination thereof. The software module can also reside in a storage medium (i.e., the memory 1300 and / or the storage 1600) such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, CD-ROM, etc. The storage medium can be coupled to the processor 1100, which can read information from and write information to the storage medium. In another method, the storage medium and the processor 1100 can also be one body. The processor 1100 and the storage medium can also reside in an application specific integrated circuit (ASIC). The ASIC can also reside in a user terminal. In another method, the processor 1100 and the storage medium can reside in the user terminal as separate components.

[0078] The above description is merely an example of the technical idea of the present application, and those of ordinary skill in the art can make various modifications and changes within the scope of the technical idea of the present application without departing from the essential characteristics of the present application. Therefore, the embodiments disclosed in the present application are not intended to limit the technical idea of the present application, but to explain the present application, and the scope of the technical idea of the present application is not limited by these embodiments. The scope of protection of the present application should be interpreted by the claims, and all technical ideas falling within the scope equivalent to the claims should be interpreted as included in the scope of the present application.

Claims

1. A driver assistance device, characterized in that including: a processing section; and a storage section containing commands executed by the processing section, the processing section: when a vehicle enables a lane change assist function, judges a possibility of collision between the vehicle and another vehicle in a target lane, when there is no possibility of collision between the vehicle and the other vehicle, calculates an expected deceleration amount of the vehicle relative to a target vehicle in the target lane to compare with a deceleration standard, and determines whether to execute a lane change assist control based on a comparison result, wherein the step of calculating the expected deceleration amount includes the steps of: calculating a required acceleration of a distance error of a preset target inter-vehicle distance and an actual distance between the vehicle and the target vehicle; calculating a required acceleration of a speed error of the vehicle and the target vehicle; calculating a required acceleration of the vehicle using the required acceleration of the distance error and the required acceleration of the speed error; and calculating the expected deceleration amount based on the required acceleration of the vehicle.

2. The driver assist device according to claim 1, wherein the processing section enables the lane change assist function based on a user input.

3. The driver assist device according to claim 2, wherein the user input is a signal generated according to a switch operation to enable the lane change assist function.

4. The driver assist device according to claim 1, wherein the processing section is configured to calculate a first required acceleration of the vehicle relative to a first target vehicle in the target lane, and calculate a second required acceleration of the vehicle relative to a second target vehicle in a travel lane, and then calculate the expected deceleration amount based on a smaller required acceleration of the first required acceleration and the second required acceleration.

5. The driver assist device according to claim 4, wherein the processing section limits the first required acceleration based on a time required for a collision of the vehicle relative to the first target vehicle.

6. The driver assist device according to claim 1, wherein the processing section calculates the deceleration standard based on a speed of the vehicle.

7. The driver assist device according to claim 6, wherein the deceleration standard is set to decrease as the vehicle speed increases.

8. The driver assist device according to claim 1, wherein when the expected deceleration amount is below the deceleration standard, the processing section determines to execute the lane change assist control.

9. The driver assist device according to claim 1, wherein when the expected deceleration amount exceeds the deceleration standard, the processing section determines not to execute the lane change assist control.

10. An operation method of a driver assist device, comprising the steps of: when a vehicle enables a lane change assist function, judging a possibility of collision between the vehicle and another vehicle in a target lane; when there is no possibility of collision between the vehicle and the other vehicle, calculating an expected deceleration amount of the vehicle relative to a target vehicle in the target lane; and comparing the expected deceleration amount with a deceleration standard to determine whether to execute a lane change assist control. ​ wherein the step of calculating the expected deceleration amount includes the steps of: calculating a required acceleration of a distance error between the vehicle and the target vehicle and a preset target inter-vehicle distance; calculating a required acceleration of a speed error between the vehicle and the target vehicle; calculating a required acceleration of the vehicle using the required acceleration of the distance error and the required acceleration of the speed error; and calculating the expected deceleration amount based on the required acceleration of the vehicle.

11. The operation method of the driver assist device according to claim 10, wherein the step of determining the possibility of the collision further includes the steps of: enabling the lane change assist function according to a user input.

12. The operation method of the driver assist device according to claim 11, wherein the user input is a signal generated according to a switch operation for enabling the lane change assist function.

13. The operation method of the driver assist device according to claim 10, wherein the step of calculating the expected deceleration amount includes the steps of: calculating a first required acceleration of the vehicle with respect to a first target vehicle in the target lane; calculating a second required acceleration of the vehicle with respect to a second target vehicle in the travel lane; and calculating the expected deceleration amount based on a smaller required acceleration between the first required acceleration and the second required acceleration.

14. The operation method of the driver assist device according to claim 13, wherein the step of calculating the first required acceleration further includes the step of: limiting the first required acceleration based on a time required for a collision of the vehicle with respect to the first target vehicle.

15. The operation method of the driver assist device according to claim 10, wherein the step of calculating the expected deceleration amount further includes the step of: calculating the deceleration criterion based on a speed of the vehicle.

16. The operation method of the driver assist device according to claim 15, wherein the deceleration criterion is set to decrease as the speed of the vehicle increases.

17. The operation method of the driver assist device according to claim 10, wherein the step of determining whether to execute the lane change assist control includes the step of: determining to execute the lane change assist control when the expected deceleration amount is below the deceleration criterion.

18. The operation method of the driver assist device according to claim 17, wherein the step of determining whether to execute the lane change assist control further includes the step of: determining not to execute the lane change assist control when the expected deceleration amount exceeds the deceleration criterion.

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