Tilt-angle detecting method and apparatus for a motorcycle

A method of calculating a tilt angle of a motorcycle, said method comprising the steps of

• detecting a steering angle of the motorcycle;
• detecting a traveling speed of the motorcycle;
• calculating a turning radius corresponding to said steering angle, wherein said turning radius is determined based on a predetermined relationship between measured steering angle values and turning radius;
• and
• obtaining a tilt angle of a vehicle body at a regular turning of the motorcycle, wherein said tilt angle is calculated based on the turning radius and said traveling speed of the motorcycle.

A tilt-angle detecting apparatus for a motorcycle, comprising:

• a steering-angle sensor for detecting a steering angle of the motorcycle;
• a vehicle speed sensor for detecting a vehicle speed;
• a regular turning-radius calculation unit for calculating a turning radius corresponding to a steering angle detected by the steering-angle sensor, wherein said turning radius is determined based on a predetermined relationship between measured steering angle values and turning radius;
• a base tilt angle calculation unit for obtaining a tilt angle of a vehicle body at a regular turning of the motorcycle, wherein said tilt angle is calculated based on the steady state turning radius calculated by the a regular turning-radius calculation unit;
• a steering-angle variation calculation unit for calculating the variation of steering angle detected by the steering-angle sensor;
• a steering-angle variation determination unit for determining whether the variation of the steering angle is equal to or greater than a predetermined value;
• and
• a lateral-G sensor for detecting the acceleration produced in a width direction of the vehicle body, the detection of the acceleration being performed when the steering-angle variation determination unit determines that the variation of the steering angle is less than the predetermined value.