Vehicle control device and vehicle control program

Abstract

A vehicle control device (70) comprises: an acquiring unit (91) that acquires a target curvature, which is the curvature of a target trajectory; an actual curvature calculating unit (92) that calculates an actual curvature, which is the curvature of a travel trajectory of a vehicle; an instructed steering angle calculating unit (93) that calculates an instructed steering angle such that the instructed steering angle increases as the target curvature increases; and an instructed steering angle correcting unit (94) that, if the target curvature is greater than or equal to a curvature determination value, corrects the instructed steering angle by feedback control based on the target curvature and the actual curvature, and if the target curvature is less than the curvature determination value, does not correct the instructed steering angle by feedback control based on the target curvature and the actual curvature.

Description

Vehicle control device and vehicle control program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2023-119184, filed on July 21, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a vehicle control device and a vehicle control program.

[0003] Patent Literature 1 describes a vehicle control device that controls the steering angle of a vehicle to make the vehicle travel along a target trajectory. The vehicle control device determines the steering angle of the vehicle based on a target curvature, which is the curvature of the target trajectory, and vehicle characteristics such as a wheelbase. The vehicle control device then performs steering control of the vehicle based on the determined steering angle.

[0004] Japanese Patent Application Laid-Open No. 2022-149546

[0005] The vehicle control device as described above has room for improvement in terms of improving the accuracy of steering control. A vehicle control device according to one aspect of the present disclosure is a vehicle control device that supports vehicle traveling along a target trajectory by outputting a commanded steering angle to a steering device that adjusts the steering angle of wheels, and includes: a target curvature acquisition unit that acquires a target curvature that is the curvature of the target trajectory; a commanded steering angle calculation unit that calculates the commanded steering angle so that it increases as the target curvature increases; an actual curvature calculation unit that calculates an actual curvature that is the curvature of the traveling trajectory of the vehicle; and a commanded steering angle correction unit that, when the target curvature is equal to or greater than a curvature determination value, corrects the commanded steering angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature, and, when the target curvature is less than the curvature determination value, does not correct the commanded steering angle by the feedback control.

[0006] A vehicle control program according to a further aspect of the present disclosure is a vehicle control program that assists the vehicle in traveling along a target trajectory by outputting a commanded steering angle to a steering device that adjusts the steering angle of the wheels, and causes a control device of the vehicle to execute a target curvature acquisition process that acquires a target curvature, which is the curvature of the target trajectory; a commanded steering angle calculation process that calculates the commanded steering angle so that it increases as the target curvature increases; an actual curvature calculation process that calculates an actual curvature, which is the curvature of the vehicle's traveling trajectory; and a commanded steering angle correction process that, when the target curvature is equal to or greater than a curvature judgment value, corrects the commanded steering angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature, and, when the target curvature is less than the curvature judgment value, does not correct the commanded steering angle by the feedback control.

[0007] The vehicle control device and vehicle control program can improve the accuracy of steering control.

[0008] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a schematic diagram of a vehicle equipped with a vehicle control device, Fig. 2 is a schematic diagram showing a target trajectory of the vehicle during automatic parking, Fig. 3 is a map showing the relationship between vehicle body speed and curvature determination value, and Fig. 4 is a flowchart showing the flow of processing performed by the vehicle control device.

[0009] 1, a vehicle 10 includes front wheels 21 and 22, rear wheels 23 and 24, a drive unit 30, a steering unit 40, a detection system 50, a driving assistance device 60, and a vehicle control device 70.

[0010] <Drive Device and Steering Device> The drive device 30 includes a motor generator 31 that generates drive force for the wheels 21 to 24, and a drive control unit 32 that controls the motor generator 31. The drive control unit 32 is an electronic control unit having a CPU and memory. The drive control unit 32 controls the motor generator 31 based on a command drive force output from the vehicle control device 70. The power of the motor generator 31 is then transmitted to the wheels 21 to 24, causing the vehicle 10 to travel.

[0011] Steering device 40 includes a steering actuator 41 that adjusts the steering angle of two front wheels 21, 22, and a steering control unit 42 that controls steering actuator 41. Steering control unit 42 is an electronic control device having a CPU and memory. Steering control unit 42 controls steering actuator 41 based on a command steering angle output from vehicle control device 70. When the steering angle of front wheels 21, 22 is adjusted by the output of steering actuator 41, vehicle 10 becomes able to turn. In this embodiment, of the plurality of wheels 21 to 24, front wheels 21, 22 correspond to the steered wheels.

[0012] <Detection System> The detection system 50 detects the state of the vehicle 10 that changes while the vehicle 10 is traveling. The detection system 50 has a plurality of sensors that detect the state of the vehicle 10, including a steering angle sensor 51, a plurality of wheel speed sensors 52, and a yaw rate sensor 53. These sensors 51 to 53 output signals according to the detection results to the vehicle control device 70.

[0013] The steering angle sensor 51 detects the steering angle of the front wheels 21, 22. The plurality of wheel speed sensors 52 correspond to the plurality of wheels 21 to 24, respectively. The plurality of wheel speed sensors 52 individually detect the rotational speeds of the plurality of wheels 21 to 24 as wheel speeds. The yaw rate sensor 53 detects the yaw rate of the vehicle 10.

[0014] <Driving Assistance Device> The driving assistance device 60 is an electronic control device having a CPU and a memory. In the driving assistance device 60, the CPU executes programs stored in the memory to realize various driving assistance functions. The driving assistance functions are functions that assist the driver in driving the vehicle 10. The driving assistance functions include, for example, automatic parking, lane keep assist, and adaptive cruise control. In the following explanation, automatic parking will be explained in detail.

[0015] As shown in FIG. 2 , automatic parking automatically parks the vehicle 10 within a parking area AR by turning the vehicle 10 while moving it backward. The driving assistance device 60 starts automatic parking control when a driver or other user requests automatic parking. In the automatic parking control, the driving assistance device 60 generates a target trajectory TR from the current position P1 of the vehicle 10 to a target position P2 set within the parking area AR. The target trajectory TR is an ideal turning trajectory for moving the vehicle 10 from the current position P1 to the target position P2. If an obstacle exists between the current position P1 and the target position P2, the target trajectory TR is preferably generated so as to avoid the obstacle. Next, the driving assistance device 60 generates a target curvature, which is the curvature of the target trajectory TR. The driving assistance device 60 then outputs the target curvature to the vehicle control device 70.

[0016] In the following description, the curvature of the travel trajectory when the vehicle 10 turns right is defined as positive, and the curvature of the travel trajectory when the vehicle 10 turns left is defined as negative. In other words, if the target trajectory TR curves so as to head right as the vehicle 10 moves forward, the target curvature will be a positive value, and if the target trajectory TR curves so as to head left as the vehicle 10 moves forward, the target curvature will be a negative value. Furthermore, if the target trajectory TR is a straight trajectory heading forward, the target curvature will be "0". Note that the relationship between the left-right direction of the vehicle 10 and the positive and negative values ​​of the target curvature may be reversed.

[0017] <Vehicle control device> As shown in Fig. 1 , the vehicle control device 70 includes a processing circuitry 80. The processing circuitry 80 is, for example, an electronic control device having a CPU 81 and a memory 82. The memory 82 stores a vehicle control program executed by the CPU 81. The CPU 81 executes the vehicle control program, causing the processing circuitry 80 to control the drive device 30 and the steering device 40. The vehicle control program is a program targeted at the control device of the vehicle 10.

[0018] <Functional Configuration of Processing Circuit> When the CPU 81 executes the vehicle control program, the processing circuit 80 functions as an acquisition unit 91, an actual curvature calculation unit 92, an instructed steering angle calculation unit 93, an instructed steering angle correction unit 94, and a steering angle instruction unit 95. These will be described in detail below.

[0019] <Acquisition Unit> The acquisition unit 91 acquires the target curvature output from the driving assistance device 60. The acquisition unit 91 also acquires state variables of the vehicle 10 based on the detection signals output from the detection system 50. More specifically, the acquisition unit 91 acquires the steering angle of the front wheels 21, 22 based on the detection result of the steering angle sensor 51, and acquires the yaw rate of the vehicle 10 based on the detection result of the yaw rate sensor 53. The acquisition unit 91 also acquires the wheel speeds of the plurality of wheels 21 to 24 based on the detection result of the wheel speed sensor 52. Furthermore, the acquisition unit 91 calculates the vehicle body speed based on the wheel speeds of the plurality of wheels 21 to 24. The steering angle, yaw rate, and wheel speed are examples of state variables. The acquisition unit 91 corresponds to a "target curvature acquisition unit" and a "state variable acquisition unit."

[0020] <Actual curvature calculation unit> The actual curvature calculation unit 92 calculates the actual curvature, which is the curvature of the travel path of the vehicle 10. More specifically, the actual curvature calculation unit 92 calculates the actual curvature by dividing the yaw rate acquired by the acquisition unit 91 by the vehicle body speed.

[0021] Here, consider a case where the actual curvature calculated based on the yaw rate includes an error of 0.1% from the true curvature. In this case, if the turning radius of the vehicle 10 is 10 m, an error of 1 cm may occur in the radial direction perpendicular to the turning direction of the vehicle 10 when the vehicle 10 turns 90°. On the other hand, if the turning radius of the vehicle 10 is 2 m, an error of 0.2 cm may occur in the radial direction perpendicular to the turning direction of the vehicle 10 when the vehicle 10 turns 90°.

[0022] That is, when the turning radius of the vehicle 10 is large, the deviation between the actual curvature calculated based on the yaw rate and the true curvature becomes larger than when the turning radius of the vehicle 10 is small. In other words, when the turning radius of the vehicle 10 is large, the accuracy of calculating the actual curvature based on the yaw rate decreases compared to when the turning radius of the vehicle 10 is small. Since the turning radius of the vehicle 10 increases as the target curvature decreases, it can be said that the accuracy of calculating the actual curvature by the actual curvature calculation unit 92 decreases as the target curvature decreases.

[0023] In this embodiment, high calculation accuracy of the actual curvature means that the deviation between the calculated actual curvature and the true curvature is small, but does not mean that the value obtained by dividing the deviation by the actual curvature is small. Incidentally, when the vehicle 10 is automatically parked, the allowable amount of deviation between the target parking position and the actual parking position does not change regardless of the turning radius of the vehicle 10.

[0024] <Instructed Steering Angle Calculation Unit> The instructed steering angle calculation unit 93 calculates an instructed steering angle that increases as the target curvature increases. For example, if the target curvature is a positive value, the instructed steering angle for turning the vehicle 10 to the right is calculated as a positive value. On the other hand, if the target curvature is a negative value, the instructed steering angle for turning the vehicle 10 to the left is calculated as a negative value. Furthermore, the instructed steering angle is calculated so that the absolute value of the instructed steering angle increases as the absolute value of the target curvature increases.

[0025] <Instructed rudder angle correction unit> The instructed rudder angle correction unit 94 corrects the instructed rudder angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature. Specifically, the instructed rudder angle correction unit 94 corrects the instructed rudder angle by feedback control based on the deviation between the target curvature and the actual curvature. More specifically, the instructed rudder angle correction unit 94 calculates a feedback term based on the deviation between the target curvature and the actual curvature. The instructed rudder angle correction unit 94 then corrects the instructed rudder angle by adding the feedback term to the instructed rudder angle calculated by the instructed rudder angle calculation unit 93. The feedback control is, for example, PID control.

[0026] As described above, the smaller the target curvature, the lower the calculation accuracy of the actual curvature. Therefore, the instructed rudder angle correction unit 94 uses the curvature judgment value to determine whether the calculation accuracy of the actual curvature is high. For example, if the absolute value of the target curvature is equal to or greater than the curvature judgment value, the calculation accuracy of the actual curvature is deemed to be high. On the other hand, if the absolute value of the target curvature is less than the curvature judgment value, the calculation accuracy of the actual curvature is deemed to be low. Then, if the absolute value of the target curvature is equal to or greater than the curvature judgment value, the instructed rudder angle correction unit 94 corrects the instructed rudder angle by feedback control based on the deviation. On the other hand, if the absolute value of the target curvature is less than the curvature judgment value, the instructed rudder angle correction unit 94 does not correct the instructed rudder angle by feedback control based on the deviation.

[0027] As described above, the actual steering angle is calculated by dividing the yaw rate by the vehicle speed. Therefore, assuming that the yaw rate is constant, the higher the vehicle speed, the smaller the actual steering angle. Therefore, if the yaw rate contains an error, the higher the vehicle speed, the smaller the effect that the yaw rate error has on the magnitude of the actual steering angle. In other words, even if the yaw rate contains an error, if the vehicle speed is high, the yaw rate error is less likely to appear as the magnitude of the actual steering angle. Therefore, the command steering angle correction unit 94 uses a curvature judgment value corresponding to the vehicle speed when determining whether the absolute value of the target curvature is equal to or greater than the curvature judgment value.

[0028] 3 is a map showing the relationship between the vehicle speed and the curvature determination value. As shown in Fig. 3, when the vehicle speed is high, the curvature determination value becomes small, and when the vehicle speed is low, the curvature determination value becomes large. The command steering angle correction unit 94 determines the curvature determination value to be used for the determination by referring to the map shown in Fig. 3.

[0029] When comparing when the vehicle 10 turns right and when it turns left, the turning behavior of the vehicle 10 may be slightly different even if the absolute values ​​of the steering angles of the front wheels 21, 22 are equal. For this reason, when the sign of the target curvature is reversed, it may be preferable not to perform feedback control immediately after the sign is reversed, based on the control amount immediately before the sign is reversed. Therefore, when the sign of the target curvature is reversed, the command steering angle correction unit 94 does not correct the command steering angle by feedback control based on the deviation between the target curvature and the actual curvature.

[0030] <Steering Angle Instructor> The steering angle instructor 95 outputs an instructed steering angle to the steering control unit 42. If the instructed steering angle is a positive value, the steering angle of the front wheels 21, 22 is adjusted so that the vehicle 10 can turn right. On the other hand, if the instructed steering angle is a negative value, the steering angle of the front wheels 21, 22 is adjusted so that the vehicle 10 can turn left. Furthermore, if the instructed steering angle is "0", the steering angle of the front wheels 21, 22 is adjusted so that the vehicle 10 can travel straight.

[0031] <Processing Contents of Processing Circuit> The processing executed by the processing circuit 80 to determine the command steering angle will be described with reference to Figure 4. This processing is repeatedly executed in a predetermined control cycle while the driving assistance device 60 is performing automatic parking control. Furthermore, this processing is executed by the CPU 81 by executing a vehicle control program stored in the memory 82.

[0032] 4, the processing circuit 80 acquires the target curvature output from the driving assistance device 60 (S11). Next, the processing circuit 80 calculates the actual curvature by dividing the yaw rate by the vehicle speed (S12). After that, the processing circuit 80 calculates the command steering angle proportional to the target curvature acquired in step S11 (S13).

[0033] The processing circuit 80 refers to a map such as that shown in Figure 3 and obtains a curvature determination value corresponding to the vehicle speed (S14). Next, the processing circuit 80 determines whether the sign of the target curvature has been reversed (S15). For example, the processing circuit 80 may compare the sign of the target curvature obtained in the previous control cycle with the sign of the target curvature obtained in the current control cycle. If the sign of the target curvature has not been reversed (S15: NO), the processing circuit 80 determines whether the absolute value of the target curvature is equal to or greater than the curvature determination value (S16).

[0034] If the absolute value of the target curvature is equal to or greater than the curvature judgment value (S16: YES), that is, if the calculation accuracy of the actual curvature is high, the processing circuit 80 corrects the commanded steering angle calculated in step S13 by feedback control based on the deviation between the target curvature and the actual curvature (S17). Next, the processing circuit 80 outputs the commanded steering angle to the steering control unit 42 (S18). Thereafter, the processing circuit 80 ends this process.

[0035] On the other hand, if the sign of the target curvature is reversed in step S15 (S15: YES), the processing circuit 80 proceeds to step S18. Also, if the absolute value of the target curvature is less than the curvature determination value in step S16 (S16: NO), that is, if the calculation accuracy of the actual curvature is low, the processing circuit 80 proceeds to step S18.

[0036] In this embodiment, step S11 corresponds to "target curvature acquisition processing." Step S12 corresponds to "actual curvature calculation processing." Step S13 corresponds to "instructed rudder angle calculation processing." Step S17 corresponds to "instructed rudder angle correction processing." Furthermore, the processing of step S11 is processing performed by the acquisition unit 91. The processing of step S12 is processing performed by the actual curvature calculation unit 92. The processing of step S13 is processing performed by the instructed rudder angle calculation unit 93. The processing of steps S14 to S17 is processing performed by the instructed rudder angle correction unit 94. The processing of step S18 is processing performed by the rudder angle instruction unit 95.

[0037] <Actions and Effects of the Present Embodiment> When automatically parking the vehicle 10, the vehicle control device 70 determines, based on the target curvature, whether to perform feedback control based on the deviation between the target curvature and the actual curvature. If the target curvature is less than the curvature determination value, the calculation accuracy of the actual curvature is deemed to be low. Therefore, if the calculation accuracy of the actual curvature is low, it is difficult to say that the accuracy of the deviation calculated using the actual curvature is also high. Therefore, if the commanded steering angle is corrected by feedback control based on a deviation with low calculation accuracy, there is a risk that the deviation between the turning trajectory of the vehicle 10 and the target trajectory TR will be larger than if the commanded steering angle is not corrected by feedback control.

[0038] Therefore, when the target curvature is less than the curvature judgment value, the vehicle control device 70 does not correct the commanded steering angle by feedback control based on the deviation between the target curvature and the actual curvature. In other words, the vehicle control device 70 can suppress the implementation of feedback control based on a deviation including an error for the commanded steering angle. This allows the vehicle control device 70 to suppress an increase in the deviation between the turning trajectory of the vehicle 10 and the target trajectory TR. In other words, the vehicle control device 70 can improve the accuracy of the steering control.

[0039] On the other hand, if the target curvature is greater than the curvature determination value, the calculation accuracy of the actual curvature can be considered high. Therefore, when the target curvature is greater than the curvature determination value, the vehicle control device 70 corrects the commanded steering angle by feedback control based on the deviation between the target curvature and the actual curvature. In other words, the vehicle control device 70 can perform feedback control on the commanded steering angle based on the deviation calculated with high accuracy. In this way, the vehicle control device 70 can cause the vehicle 10 to travel along the target trajectory TR regardless of the magnitude of the target curvature. In other words, the vehicle control device 70 can improve the accuracy of steering control.

[0040] As described above, the magnitude of the curvature determination value, which is the criterion for determining whether the calculation accuracy of the actual curvature is high, changes depending on the vehicle speed. Therefore, the vehicle control device 70 uses a curvature determination value that decreases as the vehicle speed increases. Therefore, the vehicle control device 70 can accurately determine whether the calculation accuracy of the actual curvature is high. In other words, when the vehicle control device 70 can accurately calculate the actual curvature, it can perform feedback control based on the deviation between the target curvature and the actual curvature.

[0041] <Modifications> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0042] The actual curvature calculation method of the actual curvature calculation unit 92 may be a calculation method that does not use the yaw rate. For example, the actual curvature calculation unit 92 may calculate the actual curvature based on the speed difference between the wheel speed of the right wheel and the wheel speed of the left wheel and the tread bases of the right wheel and the left wheel. Even when calculating the actual curvature in this way, the calculation accuracy of the actual curvature changes depending on the vehicle speed. Therefore, the curvature determination value may be changed depending on the vehicle speed.

[0043] The commanded steering angle calculation unit 93 may calculate the commanded steering angle based on not only the target curvature but also vehicle characteristics such as the wheelbase and weight distribution. Also, the commanded steering angle calculation unit 93 may calculate the commanded steering angle based on not only the target curvature but also road surface characteristics such as the road surface gradient.

[0044] In the above embodiment, so-called reverse parking is given as an example of automatic parking, but the driving assistance device 60 may also perform automatic parking control to automatically perform so-called forward parking and parallel parking. Note that when performing reverse parking and forward parking, the positive and negative signs of the target curvature may not be reversed, but when performing parallel parking, the positive and negative signs of the target curvature are reversed.

[0045] The command steering angle correction unit 94 may use a constant curvature determination value that does not change depending on the vehicle speed. In the flowchart shown in Figure 4, if the sign of the target curvature is reversed (S15: YES), the processing circuit 80 may reset the integral term to "0" under circumstances in which PID control is performed. In this case, after resetting the integral term to "0", the processing circuit 80 may proceed to step S16 or step S18. In other words, even if the sign of the target curvature is reversed, the processing circuit 80 may correct the command steering angle by feedback control based on the proportional term as long as the integral term is reset to "0".

[0046] In the vehicle 10, both the front wheels 21, 22 and the rear wheels 23, 24 may be steerable wheels. Alternatively, in the vehicle 10, of the front wheels 21, 22 and the rear wheels 23, 24, only the rear wheels 23, 24 may be steerable wheels.

[0047] In the vehicle 10, the motor generator 31 can be replaced with an internal combustion engine. The driving assistance device 60 and the vehicle control device 70 are not limited to processing circuits that include a CPU and ROM and execute software processing. For example, the driving assistance device 60 and the vehicle control device 70 may include dedicated hardware circuits that execute at least some of the various processes executed in the above-described embodiment. An example of a dedicated hardware circuit is an ASIC. ASIC is an abbreviation for "Application Specific Integrated Circuit." In other words, the driving assistance device 60 and the vehicle control device 70 may have any of the following configurations (a) to (c):

[0048] (a) A processing circuit comprising a processing device that executes all of the above processes according to a program and a program storage device such as a ROM that stores the program. (b) A processing circuit comprising a processing device and program storage device that executes part of the above processes according to a program, and a dedicated hardware circuit that executes the remaining processes.

[0049] (c) A processing circuit comprising dedicated hardware circuits for executing all of the above processes, wherein the software execution device comprising a processing device and a program storage device, and the dedicated hardware circuits may be plural.

[0050] <Technical Concept> The technical concept that can be understood from the above-described embodiment and modified examples will be described. [Supplementary Note 1] A vehicle control device including a state variable acquisition unit that acquires state variables of the vehicle that indicate a turning behavior of the vehicle, and the actual curvature calculation unit that calculates the actual curvature based on the state variables.

[0051] [Supplementary Note 2] The vehicle is equipped with a yaw rate sensor that detects the yaw rate of the vehicle, and the actual curvature calculation unit calculates the actual curvature by dividing the yaw rate based on the detection signal of the yaw rate sensor by the body speed of the vehicle.

[0052] [Appendix 3] A vehicle control method for assisting a vehicle in traveling along a target trajectory by outputting a commanded steering angle to a steering device that adjusts the steering angle of wheels, the method comprising: a target curvature acquisition process for acquiring a target curvature, which is the curvature of the target trajectory; a commanded steering angle calculation process for calculating the commanded steering angle so that the commanded steering angle increases as the target curvature increases; an actual curvature calculation process for calculating an actual curvature, which is the curvature of the traveling trajectory of the vehicle; and a commanded steering angle correction process for correcting the commanded steering angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature when the target curvature is equal to or greater than a curvature judgment value, and not correcting the commanded steering angle by the feedback control when the target curvature is less than the curvature judgment value.

[0053] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A vehicle control device that assists a vehicle in traveling along a target trajectory by outputting a commanded steering angle to a steering device that adjusts the steering angle of wheels, comprising: a target curvature acquisition unit that acquires a target curvature, which is the curvature of the target trajectory; a commanded steering angle calculation unit that calculates the commanded steering angle so that it increases as the target curvature increases; an actual curvature calculation unit that calculates an actual curvature, which is the curvature of the vehicle's traveling trajectory; and a commanded steering angle modification unit that, when the target curvature is equal to or greater than a curvature judgment value, modifies the commanded steering angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature, and, when the target curvature is less than the curvature judgment value, does not modify the commanded steering angle by the feedback control.

2. The vehicle control device according to claim 1, wherein the command steering angle correction unit uses a larger curvature determination value when the vehicle speed is low than when the vehicle speed is high.

3. A vehicle control program that assists a vehicle in traveling along a target trajectory by outputting a command steering angle to a steering device that adjusts the steering angle of wheels, the vehicle control program causing a control device of the vehicle to execute the following: a target curvature acquisition process to acquire a target curvature, which is the curvature of the target trajectory; a command steering angle calculation process to calculate the command steering angle so that it increases as the target curvature increases; an actual curvature calculation process to calculate an actual curvature, which is the curvature of the traveling trajectory of the vehicle; and a command steering angle correction process that, when the target curvature is equal to or greater than a curvature judgment value, corrects the command steering angle by feedback control based on the target curvature and the actual curvature so that the actual curvature approaches the target curvature, and, when the target curvature is less than the curvature judgment value, does not correct the command steering angle by the feedback control.

Images