Shintaroh Murakami

Motion analysis of a motorcycle taking into account the rider's effects

In this paper, to analyse the riders effects on the motion of a motorcycle, we model a rider–motorcycle system by taking into account the leaning motion of the riders upper torso and his/her arm connection with the handlebars. The nonlinearity of the tyre force is introduced by utilising hyperbolic tangent functions to approximate a Magic Formula tyre model. On the basis of a derived nonlinear state-space model, we analyse the effects of not only the riders arms but also his/her postures during steady turning by simulations. The riders postures including lean-with, lean-in and lean-out are realised by adding the lean torque to the riders upper torso. The motorcycle motion and the riders effects are analysed in the case where the friction coefficient of the road surface changes severely during steady turning. In addition, a linearised state-space model is derived during steady turning, and a stability analysis of the rider–motorcycle system is performed.

Stabilization Control of a Motorcycle During Braking

In this paper, a front-steering assist control is designed to stabilize a motorcycle during braking. The rider-motorcycle system with its pitching motions is linearized around an equilibrium point of quasi-steady state straight running with constant deceleration. From the viewpoints of eigenvalues and frequency responses, the linearized model is analyzed and a reduced-order model is obtained to design the control system by using H∞ control theory. By carrying out simulations during braking, it is demonstrated that the control system can stabilize a motorcycle when receiving a sudden disturbance from the front wheel and is robust against parameter variations and several braking situations.Copyright

Steering assist control for stabilization of a motorcycle during braking (verification of the control system on cornering simulations)

In this paper, a front-steering assist control system is designed to stabilize a motorcycle during braking by the rider. A rider-motorcycle system is derived by applying multi-body dynamics in consideration of riders pitching motion, and is linearized around an equilibrium point of quasi-steady state straight running with a constant deceleration. From the viewpoints of eigenvalues and frequency responses, the linearized model is analyzed and the reduced-order model is obtained to design the control system by using H∞ control theory. By carrying out simulations, it is demonstrated that the control system can stabilize the motorcycle when the rider applies the brakes during cornering and is robust against parameter variations and other braking situations.

Modal Analysis of a Motorcycle Motion During Braking for its Stabilization Control System Design

In this paper, modal motion of a motorcycle during braking is analyzed to clarify influence of a stabilization control system designed to the modes. A thirteen degree-of-freedom nonlinear state-space model including rider’s motion is linearized around an equilibrium point of quasi-steady state straight running with constant deceleration, and the modal analysis is carried out using the linearized state-space models. Conducting mode separation and performing simulations utilizing the linearized state-space models, the behavior of the modes including capsize, weave, and wobble modes are analyzed. The characteristic of each mode is clarified from relationships among the impulsive responses of simulations and the eigenvectors obtained from eigenanalysis. Furthermore, the influence of a motorcycle stabilization control system to each mode is analyzed from simulation results.© 2013 ASME