Patent ID: 7142961

Claim:
A method for quantitatively analyzing steer characteristics to acquire steering stability of a vehicle and a tire, comprising the steps of: mounting a real-vehicle measurement device to the vehicle; performing a variety of real-vehicle tests including a lane-changing test, a severe lane-changing test, a circuit cornering test, and a power on/off test in a vehicle turning operation, and acquiring measurement data; calculating a turning curvature, a turning velocity, a nose angle, and a nose-angle time rate on the basis of the acquired measurement data; comparing the turning curvature, the turning velocity, the nose angle, and the nose-angle time rate with reference data, including a reference turning curvature, a reference turning velocity, reference nose-angle and reference nose-angle time rate respectively; calculating a slope, a change rate, and a change amount of the nose angle during the power on/off test; and determining a steer characteristic degree on the basis of a result of the comparison and the calculated slope, change rate and change amount of the nose angle.