Multibody Motorcycle Model Research Articles

Motorcycle final drive geometry optimization on uneven roads

The design of transmission systems plays an important role in the dynamic performance of motorcycles. It is well known that power delivery and stability in motorcycles is strongly affected by the geometry of the final drive.This article presents a 2D multibody motorcycle model in which the tire and final drive are considered thoroughly. A nonlinear transient model is used to reproduce forces between the tire and the road. The engine and wheel sprockets, the squat ratio and the chain slack have been taken into account in the final drive kinematic model.The configuration of the final drive elements and its influence on the distance covered by the motorcycle have been studied. Furthermore, the motorcycle final drive design has been optimized to maximize the distance traveled on different uneven roads.Simulations show a superior performance of the motorcycle when the configuration of the final drive elements is optimized. This study contributes to demonstrating the importance of the configuration and geometry of the final drive to improve stability and overall behavior of the motorcycle on uneven roads.

Driveline instability of racing motorcycles in straight braking manoeuvre

Experimental evidence shows that a self-excited vibration may appear during braking manoeuvres performed by road-racing motorcycles. It involves vertical oscillation of front and rear wheel axles as well as angular oscillation of the driveline in a frequency range between 17 and 22 Hz. As a consequence, severe oscillations of the tyre-ground vertical loads can be observed, leading to a loss of grip and ultimately weakening the vehicle overall performance. Several contributions on this topic can be accounted for in the literature; however, a comprehensive description of the phenomenon has not been given yet. The present work is aimed at simulating the above vibration with a planar multibody motorcycle model, and then at analyzing its driving mechanism. Stability maps are drawn for time-invariant braking manoeuvres, and validated with respect to time domain simulations.

Motorcycle Analytical Modeling Including Tire–Wheel Nonuniformities for Ride Comfort Analysis

ABSTRACT The transmission of vibrations in motorcycles and their perception by the passengers are fundamental in comfort analysis. Tire nonuniformities can generate self-excitations at the rotational frequency of the wheel and contribute to the ride vibration environment. In this work a multi-body motorcycle model is built to evaluate the ride comfort with respect to tire nonuniformities. The aim is to obtain a multi–degrees-of-freedom dynamic model that includes both the contributions of the motorcycle and tire–wheel assembly structures. This representation allows the tire nonuniformities to predict the vertical force variations on the motorcycle and can be used through a root mean square acceleration evaluation for ride comfort analysis. The motorcycle model proposed is a 10-degrees-of-freedom system, where each tire–wheel is a 4-degrees-of-freedom model. The tire–wheel assemblies include two types of nonuniformities: lumped mass imbalance and radial run-out. Simulations of analytical models are compared with experimental tests.

Motorcycle Cornering Behaviour Modelling

The market for motorcycles has been showing a continuous increase in sales in last years. This result is driven by the change of perception by the consumers not to despise the two-wheeled vehicle as a transport. Fuel economy, parking easiness and speed of locomotion confirm the absorption of this product on the market. But the growth of scientific research in motorcycles dynamics do not grow at the same market rate, making it an issue to be exploited to improve the safety of the rider or assist in new projects development. This work uses a multi body motorcycle model containing 4 rigid bodies connected by revolution joints parameterized by 7 degrees of freedom. The model includes the major geometric and inertial characteristics of the motorcycle. It was used in the mathematical model nonlinear algebraic equations. The model is subjected to curvilinear trajectory with constant radius and speed which allows knowing the behaviour of the motorcycle on a steady state manoeuvre, using two input parameters imposed by the rider: angle of steering and roll angle. The simulation results are discussed and presented in graphical form. Aiming to validate the mathematical model an instrumented motorcycle with data acquisition equipment was used, comparing the testing values with those obtained in the mathematical model. The test procedure was exclusively developed for this work and has not been reported in the literature, fostering effective ways to test and validate this investigation.

A multibody motorcycle model with rigid-ring tyres: formulation and validation

The aim of this paper is the development and validation of a three-dimensional multibody motorcycle model including a rigid-ring tyre model, taking into account both the slopes and elevation of the road surface. In order to achieve accurate assessment of ride and handling performances of a road racing motorcycle, a tyre model capable of reproducing the dynamic response to actual road excitation is required. While a number of vehicle models with such feature are available for car application, the extension to the motorcycle modelling has not been addressed yet. To do so, a novel parametrisation for the general motorcycle kinematics is proposed, using a mixed reference point and relative coordinates approach. The resulting description, developed in terms of dependent coordinates, makes it possible to include the rigid-ring kinematics as well as road elevation and slopes, without affecting computational efficiency. The equations of motion for the whole multibody system are derived symbolically and the constraint equations arising from the dependent coordinate formulation are handled using the position and velocity vector projection technique. The resulting system of equations is integrated in time domain using a standard ordinary differential equation (ODE) algorithm. Finally, the model is validated with respect to experimentally measured data in both time and frequency domains.

Traction Control for Ride-by-Wire Sport Motorcycles: A Second-Order Sliding Mode Approach

This paper addresses the analysis and design of a safety-oriented traction control system for ride-by-wire sport motorcycles based on the second-order sliding mode methodology. The controller design is based on a nonlinear dynamical model of the rear wheel slip, and the modeling phase is validated against experimental data measured on an instrumented vehicle. To comply with practical applicability constraints, the position of the electronic throttle body is used as control variable and the effect of the actuator dynamics is thoroughly analyzed. After a discussion on the interplay between the controller parameters and the tracking performance, the final design effectiveness is assessed via mechanical simulation corporation BikeSim, a full-fledged commercial multibody motorcycle model.

How a rear steering system may improve motorcycle dynamics

This research investigates how motorcycle dynamics may be improved by applying a steering system on the rear wheel. The study is carried out using a widely validated multi-body model of motorcycle and rider. Two types of rear steering systems are compared: a self-steering wheel coupled with a spring-damper assembly and a controlled steering wheel, whose steering angle is governed accordingly to a first-order relationship between front and rear steering angle. In general, any rear steering system transfers energy from weave mode to wobble mode. Thus, both solutions stabilise high-speed weave, but increase instability when braking. The passive system shows unexpected reactions when accelerating in cornering condition, whereas the active system is almost neutral.

Simulation of motorcyclist's kinematics during impact with W-Beam guardrail

W-Beam guardrail system has been in use as a standard for roadside safety barrier since 1950s. Recently, its safety performance standard has been upgraded to absorb impact from large vehicles. This performance standard requires guardrail system to be capable of capturing and redirecting a large range of vehicle types and sizes but its effects on safety of motorcyclists are not yet understood. The paper describes a three-dimensional computer simulation of the kinematics impact of motorcycle and dummy rider with W-Beam guardrail inclined at angles 45 and 90° to the initial direction of travel. The simulation is based on the test procedure recommended by ISO 13232 on the configurations for motorcycle–car impact. The focus of this study is not on the motorcycle change in velocity, but on the rider's kinematics and acceleration vs. time history. Multibody model of motorcycle and finite element model of guardrail were developed in commercially available software. The simulation results are presented in this paper in form of kinematics and acceleration vs. time history.