Course estimator and method of estimating a state of a course of a vehicle and a non-transitory computer-readable storage medium for the same

A non-transitory computer-readable storage medium containing thereon a program comprising instructions, the instructions comprising:

• obtaining, with a drive assist electronic control unit of a vehicle, first information from a radar sensor and an imaging device located in the vehicle, the drive assist electronic control unit having a first processor and a first memory;
• estimating, with the drive assist electronic control unit, a first radius and a first turning direction of a first forward traveling path on the basis of the first information, the first forward traveling path being a part of a forward traveling path of a road on which the vehicle is going to travel;
• obtaining, with the drive assist electronic control unit, second information from the radar sensor and the imaging device;
• estimating, with the drive assist electronic control unit, a second radius and a second turning direction of a second forward traveling path on the basis of the second information, the second forward traveling path being a part of the forward traveling path of the road on which the vehicle is going to travel, the second forward traveling path being ahead of the first forward traveling path and farther from the vehicle than the first forward traveling path;
• determining, with the drive assist electronic control unit, whether an absolute value of a difference between the first radius and the second radius is greater than a predetermined threshold;
• determining, with the drive assist electronic control unit, whether the first turning direction of the first forward traveling path is inverted from the second turning direction of the second forward traveling path in response to determining that the absolute value of the difference is greater than the predetermined threshold;
• determining, with the drive assist electronic control unit, that a changing point exists in the road between the first forward traveling path and the second forward traveling path in response to determining that the absolute value of the difference is greater than the predetermined threshold and that the first turning direction of the first forward traveling path is inverted from the second turning direction of the second forward traveling path;
• determine, with the drive assist electronic control unit, that the changing point does not exist in the road between the first forward traveling path and the second forward traveling path in response to at least one of determining that the absolute value of the difference is not greater than the predetermined threshold and determining that the first turning direction of the first forward traveling path is not inverted from the second turning direction of the second forward traveling path;
• setting, with the drive assist electronic control unit, a specified time period to be a first time period in response to determining that that the changing point does not exist in the road between the first forward traveling path and the second forward traveling path;
• setting, with the drive assist electronic control unit, the specified time period to be a second time period in response to determining that that the changing point exists in the road between the first forward traveling path and the second forward traveling path, the second time period being longer than the first time period;
• recognizing, with the drive assist electronic control unit, positions of leading vehicles which are disposed ahead of the vehicle using the radar sensor and the imaging device;
• selecting, with the drive assist electronic control unit, from the leading vehicles, a following target vehicle that satisfies a predetermined condition continuously for a duration of the specified time period, the predetermined condition being that the following target vehicle is located at a shortest distance from the vehicle among the leading vehicles for the duration of the specified time period;
• and
• controlling, with an engine electronic control unit located in the vehicle and having a second processor and a second memory, a throttle of the vehicle to increase or decrease a driving force on the vehicle, and controlling, with a brake electronic control unit located in the vehicle and having a third processor and a third memory, a brake actuator to increase or decrease braking force on the vehicle to keep a predetermined distance between the vehicle and the following target vehicle selected by the drive assist electronic control unit during operation of the vehicle.