Straight-traveling/turning determination device

A straight-traveling/turning determination device, comprising:

• a vehicle speed detector that detects vehicle speed;
• an acceleration detector that detects vehicle acceleration;
• a front wheel rotary speed detector that detects rotary speed of a front wheel;
• a rear wheel rotary speed detector that detects rotary speed of a rear wheel;
• a rotary speed comparison value calculator that calculates a rotary speed comparison value based on a comparison between the rotary speed of the front wheel and the rotary speed of the rear wheel;
• and
• a straight-traveling/turning determiner that determines whether a vehicle is traveling straight or turning based on magnitude of the rotary speed comparison value,
• wherein the straight-traveling/turning determiner uses the rotary speed comparison value under straight-traveling conditions as a straight-traveling rotary speed comparison value, the straight-traveling conditions including:
• the vehicle speed is equal to or lower than first predetermined speed,
• an absolute value of the vehicle acceleration is equal to or smaller than predetermined acceleration, and
• a turn signal is not being actuated, and
• wherein the straight-traveling/turning determiner determines that the vehicle is turning if one of a ratio and a difference between an instant rotary speed comparison value and the straight-traveling rotary speed comparison value exceeds a threshold.

A method for determining whether a vehicle is traveling straight or turning, comprising:

• detecting vehicle speed from a vehicle speed detector;
• detecting vehicle acceleration from an acceleration detector;
• detecting rotary speed of a front wheel from a front wheel rotary speed detector;
• detecting rotary speed of a rear wheel from a rear wheel rotary speed detector;
• periodically calculating a rotary speed comparison value based on a comparison between the rotary speed of the front wheel and the rotary speed of the rear wheel;
• setting a straight-traveling rotary speed comparison value from a particular rotary speed comparison value under straight-traveling conditions, the straight-traveling conditions including:
• the vehicle speed is equal to or lower than first predetermined speed,
• an absolute value of the vehicle acceleration is equal to or smaller than predetermined acceleration, and
• a turn signal is not being actuated;
• and
• determining that the vehicle is turning if one of a ratio and a difference between an current rotary speed comparison value and the straight-traveling rotary speed comparison value exceeds a threshold.