Method and apparatus for controlling a semi-active suspension system for motorcycles
View Patent ↗A method and an apparatus for controlling a semi-active suspension system ( 1 ) for motorcycles are described. According to the present invention, the damping forces applied to controllable force generators ( 2, 3 ), such as controllable shock absorbers, provided to the front and the rear semi-active suspensions of a motorcycle are jointly controlled. In particular, the pitch velocity (V p ) of the suspended mass (M s ) is taken into account so as to jointly control the front and rear suspension systems of a motorcycle. The present invention allows the optimization of the global adherence of the motorcycle to the road surface and of the driving and the travelling comfort of the vehicle.
1. A semi-active suspension system for a motorcycle having a suspended mass including a motorcycle body and a non-suspended mass including front and rear wheels comprising:
front relative velocity means, coupled between the suspended mass of the motorcycle body and the non-suspended mass of the front wheel, for providing a front relative velocity signal representative of the relative velocity between the suspended mass of the motorcycle body and the non-suspended mass of the front wheel;
rear relative velocity means, coupled between the suspended mass of the motorcycle body and the non-suspended mass of the rear wheel, for providing a rear relative velocity signal representative of the relative velocity between the suspended mass of the motorcycle body and the non-suspended mass of the rear wheel;
pitch velocity means, coupled to the suspended mass of the motorcycle body, for providing a pitch velocity signal representative of a pitch velocity of the suspended mass of the motorcycle body;
a front controllable force generator placed between the suspended mass of the motorcycle body and the non-suspended mass of the front wheel;
a rear controllable force generator placed between the suspended mass of the motorcycle body and the non-suspended mass of the rear wheel;
a controller coupled to said front relative velocity means, rear relative velocity mans, pitch velocity means, front controllable force generator, and rear controllable force generator;
wherein said controller provides control signals for regulation of said front and rear controllable force generators based on a predetermined control policy for optimizing global adherence of the motorcycle to a road surface, the predetermined control policy comprises a three dimensional control surface defined by a function of the front relative velocity signal, the rear relative velocity signal, and the pitch velocity signal, and the three-dimensional control surface is calculated to provide a predetermined performance index comprising a vertical load on the front and rear non-suspended masses and acceleration, whereby the predetermined performance index is optimized taking into account road handling and degree of comfort;
wherein said controller provides a multiplicative factor control signal for further regulation of said front and rear controllable force generators providing variable damping as a function of speed of the motorcycle wherein the multiplicative factor control signal has a first growth rate having a first slope at a lower motorcycle speed, a second growth rate having a second slope at an intermediate motorcycle speed, and a third growth rate having a third slope at a higher motorcycle speed, wherein the first slope is less than the second slope and the third slope is negative relative to the first and second slopes; and
wherein said controller provides control signals for regulation of said front and rear controllable force generators and the multiplicative factor control signal has a slope of a correction gain of the variable damping and changes in three steps with respect to motorcycle speed, wherein the lower motorcycle speed region is up to 60 km/hour, wherein the intermediate motorcycle speed region is from 60 to 150 km/hour, and wherein the higher motorcycle speed region is over 150 km/hour,
whereby driving and traveling comfort of the motorcycle is improved.