Control of motorcycles by variable geometry rear suspension

Cornering weave oscillations associated with high performance motorcycles operating at high speeds, can be reduced by controlling the geometry of the rear suspension. A conventional monoshock rear suspension arrangement is modified and extended in a way that variations of the leverage ratio between the spring damper unit and road wheel are possible by an actuator. The actuator varies the geometry by controlling the displacement between two moving parts. The design analysis makes use of a high fidelity mathematical motorcycle model whose parameter set is based on a Suzuki GSX-R1000 sports machine. A displacement control strategy is developed based on classical Bode-Nyquist frequency response ideas. The controller further utilises an integrator anti-windup scheme to conform with the limited displacement space, and to limit the maximum actuator force and power requirements. Simulation results are included to demonstrate that significant improvements can be obtained with an actuator of practical dimensions.