Automatic steering control device

An automatic steering control device comprising:

• a steering assist device configured to calculate, on a basis of a target travel road shape and a state quantity, a first instruction value to be output to a steering device mounted on a vehicle to cause the vehicle to travel along the target travel road shape, the target travel road shape being calculated on a basis of one or both of external environment information of the vehicle and map information, the state quantity being output from a state quantity detection device configured to detect the state quantity including a vehicle speed and an acceleration of the vehicle;
• and
• a steering control unit configured to control the steering device on the basis of the first instruction value during automatic driving of the vehicle,
• wherein the steering control unit comprises
• an input-output unit configured to communicate with the steering assist device and the state quantity detection device,
• a memory unit configured to store a future travel road shape that is the target travel road shape for a predetermined time period from a present time and the state quantity at the present time,
• a first abnormality detection unit configured to detect occurrence of a failure in one or both of operation of the steering assist device or communication between the steering assist device and the input-output unit,
• a second abnormality detection unit configured to detect occurrence of a failure in one or both of the operation of the state quantity detection device or the communication between the steering assist device and the input-output unit,
• an instruction value computation unit configured to
• calculate, on the basis of the state quantity input from the state quantity detection device and the future travel road shape stored in the memory unit, a second instruction value to be output to the steering device to cause the vehicle to travel along the future travel road shape when a first failure state is entered in which the occurrence of the failure is detected by the first abnormality detection unit during the automatic driving, and
• calculate, on a basis of the latest vehicle speed and acceleration and an elapsed time from the occurrence of a second failure state, a current estimated vehicle speed of the vehicle and a travel distance of the vehicle from a position of the occurrence of the second failure state and calculate, on a basis of a comparison of the current estimated vehicle speed and the travel distance with the future travel road shape stored in the memory unit, a third instruction value to be output to the steering device to cause the vehicle to travel along the future travel road shape when the second failure state is entered in which the occurrence of the failure is detected by the first abnormality detection unit and the second abnormality detection unit during the automatic driving, and
• a switching unit configured to control the steering device on the basis of the first instruction value output from the steering assist device in a normal state in which no failure is detected by the first abnormality detection unit and the second abnormality detection unit during the automatic driving, control the steering device on the basis of the second instruction value output from the instruction value computation unit in the first failure state, and control the steering device on the basis of the third instruction value output from the instruction value computation unit in the second failure state.