The US Patent Office has granted a patent to Mechanical Simulation Corporation for a new method of stabilising motorcycles. The system method uses high-fidelity computer simulation models of two- or three-wheel motorcycles to predict operating states such as yaw rate, lateral acceleration and roll angle for a stable motorcycle at a given speed and steer angle.
The technology was developed by Mechanical Simulation Corporation engineers, Dr Yukio Watanabe and Dr Michael Sayers, and the system (patent US 10,435,016 B2) measures the operating state of a physical motorcycle and compares it with that of the computational model to determine if there is a pending loss of stability. The nature of that difference is used to intervene with the brakes, modulating the engine torque, and applying steering torque independently of the human rider.
The motivation for the work was to help eliminate the instability that motorcycles can exhibit when operating at high speeds and at high cornering levels. In some situations, motorcycles can exhibit an oscillation known technically as ‘weave’ and as the rather more sinister ‘widow-maker vibration’ among riders. The weave motion of motorcycles was theoretically identified in the early 1970s, and manufacturers have since tried to eliminate weave motion by avoiding excessive weight on the rear wheel, tuning spring and dampers, and other adjustments. However, no one has tried previously to remove (or reduce) the weave motion by computer application of brakes, throttle and steering.
Generally speaking, applying the brakes on motorcycles during oscillatory motion at high speed is dangerous. However, the application of brakes with coordination to the oscillation at a certain timing (this is a part of the claimed invention) can effectively reduce the speed and reduce the weave oscillation to stabilise the motorcycle. The brakes are applied precisely with rapid coordination of the oscillatory frequency of motorcycle motion, with the process being faster than would be possible to achieve by a human rider.
The issue of high-speed stability is becoming more significant as many high-end motorcycles provide more power, and tandem riding becomes legal on highways in some Asian countries.
Dr Watanabe stated, “the invented system method can be considered as the next generation of stability control, which can be prepared for unexpected oscillatory behaviour of motorcycles and personal mobility vehicles during high-speed cruising.”
