Development of the Anti-Lift-Control for Motorcycle 2018-32-0076
In motorcycle market, there is demand for technology that makes it possible to
drive fast safely. One such technology has already been commercialized; control
that prevents front lift while enabling maximum acceleration performance. We
have developed a more accurate version of this control.
In order to maximize acceleration performance, it is necessary to keep front lift
angle as close to zero as possible. Reducing output driving force helps to keep
the front lift angle low, but if output driving force is reduced too much, it
will degrade acceleration performance. Feedback control that reduces output
driving force when front lift is detected is effective for optimizing this trade
off, but increasing feedback gain too much to reduce front lift angle will cause
output driving force to change suddenly, making for a less comfortable ride. In
order to solve this problem, we introduced feedforward control that estimates
the equilibrium between power and front lift and restricts output driving force.
Estimates should be made by measuring the pitching angular acceleration of the
actual body of the vehicle in order to correct for error. However when there is
no front lift, pitching angular acceleration is always zero so an estimate
cannot be made. Therefore when there is no front lift, the open loop estimated
from the geometry of the vehicle shall be used as the estimate, to be switched
for the closed loop estimate from the actual pitching angular acceleration when
front lift is detected.
Using the control method, while keeping the front lift angle close to zero, we
were able to perform accurate control to meet the demand for maximum
acceleration performance without reducing driving force too much.