Safe following distance estimation system and estimation method thereof

A safe following distance estimation method, adapted for an autonomous vehicle, comprising:

• sensing, by a sensor, at least one of a first longitudinal velocity, a first lateral velocity, image data, and LiDAR data of an adjacent vehicle to generate first sensing data, and sensing, by the sensor, at least one of a second longitudinal velocity, a second lateral velocity, a wheel velocity, a wheel deflection angle, a yaw rate, and an inclination angle of the autonomous vehicle to generate second sensing data, wherein the adjacent vehicle is adjacent to the autonomous vehicle;
• calculating, by a processor, a first friction parameter between wheels of the adjacent vehicle and a pavement according to pavement material data;
• calculating, by a processor, a second friction parameter between wheels of the autonomous vehicle and the pavement according to the second sensing data;
• calculating, by the processor, a safe following distance between the autonomous vehicle and the adjacent vehicle according to the first sensing data from the sensor, the second sensing data from the sensor, the first friction parameter, and the second friction parameter;
• receiving, by the processor, a high-precision map through a communication system;
• and
• generating, by the processor, the pavement material data according to the high-precision map,
• wherein calculating the safe following distance between the autonomous vehicle and the adjacent vehicle according to the first sensing data, the second sensing data, the first friction parameter, and the second friction parameter comprises:
• identifying a dynamic specification of the adjacent vehicle according to the first sensing data, wherein the dynamic specification comprises a maximum deceleration of the adjacent vehicle;
• calculating a first maximum deceleration of the adjacent vehicle according to the dynamic specification and the first friction parameter of the adjacent vehicle;
• calculating a second minimum deceleration of the autonomous vehicle according to the second friction parameter of the autonomous vehicle;
• calculating a third maximum acceleration of the autonomous vehicle according to a rolling friction parameter of the autonomous vehicle;
• and
• calculating the safe following distance according to the first maximum deceleration, the second minimum deceleration, and the third maximum acceleration.