The article shows the validity of four-wheel steering (4WS) bicycle model. At the beginning it is presented in which tasks, connected with 4WS vehicles, the bicycle model is applied. Then the equations in local coordinate system and their forms in global coordinate system are presented. The research tested the response of the model to a lane change manoeuvre, using transfer functions and a “bang-bang” control signal. The transfer functions was connected with static ratio characteristic to construct full four-wheel steering model. A reference signal generator and vehicle model were constructed in analytical form and checked in Matlab&Simulink using sample vehicle’s data from another literature item. One example of simulations was shown. The results presented led to interesting conclusions and indicated directions for further research. This research will include the issue of regulators derivation. This will allow for the construction of a fully functioning control system. The effects of this activities will be tested again in simulation environment.
Torsional vibrations of steering systems are significant problems for the active safety of motorcycles. These vibrations may occur even with slight disturbances of the steady state motion, and their causes result from the improper mechanical parameters and characteristics of the steering system affecting the dynamic properties of the vehicle. In many cases, full elimination of torsional vibrations requires the use of special dampers acting as mechatronic systems. Identifying the causes of vibrations and finally the proper synthesis of the active damper requires research studies using mathematical modelling and computer simulation. Due to the complex nature of motorcycle dynamics, which prompts the creation of complex forms of the mathematical model, and at the same time the obvious paradigm of the relative simplicity of the model used in mechatronic systems, the synthesis of such a model requires a special approach. The paper presents a method of model synthesis including determination of nonlinear equations of motion in an extreme "expanded" version, then their linearization, Laplace transformation and determination of the transfer functions, frequency analysis based on Bode plots, reduction of the transfer functions and finally calculation of state equations allowing a synthesis of the active damper algorithm.
This paper presents a vibration analysis method and an example of its application to evaluate the influence of mass parameters on torsional vibration frequencies in the steering system of a motorcycle. The purpose of this paper is to analyze to what extent vibration frequencies can change during their daily operation. These changes are largely due to the ratio of vehicle weight to driver and load. The complex dynamics make it very difficult to conduct research using simple models. It is difficult to observe the influence of individual parameters because they are strongly interrelated. This paper provides a description of the vibration analysis method, and the results are presented in the form of Bode diagrams and tables. On this basis, it was found that the driver, deciding on the way of using the vehicle and introducing modifications in it, influences the resonant frequencies of the steering system. Typical exploitation factors, on the other hand, do not cause significant changes, although they may contribute to increasing the sensitivity of the system to vibrations. The conducted analysis also showed some nonlinear changes in the dynamics of the system with linear changes of the parameter values.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.