Steering determination device and autonomous driving system

A steering determination device that determines a steering state in which a driver of a vehicle is steering a steering wheel of the vehicle, based on a steering torque of a steering shaft, the device comprising:

• a torque recognition unit configured to recognize the steering torque based on a result of measurement performed by a torque sensor provided on the steering shaft;
• an acceleration recognition unit configured to recognize longitudinal acceleration in a longitudinal direction of the vehicle or lateral acceleration in a lateral direction of the vehicle based on a result of measurement performed by an accelerator sensor of the vehicle;
• a threshold value setting unit configured to set a threshold value used for a determination of the steering state, based on the longitudinal acceleration or the lateral acceleration;
• and
• a steering determination unit configured to determine that the driver is in the steering state if the steering torque is equal to or greater than the threshold value,
• wherein the threshold value setting unit is configured to set the threshold value such that the threshold value decreases as an absolute value of the longitudinal acceleration or the lateral acceleration decreases.