86466 - Motorcycle Vehicle Dynamics

Learning outcomes

Students are introduced to procedures and methods for modelling, identification, design, analysis of dynamical models of motorcycle systems. Tools: - analytical tools, to understand the basic system mechanical behaviour; - numerical tools, in order to simulate complex mechanical systems; - experimental tools, to make it possible critical parameters to be identified.

Course contents

• Motorcycle kinematics
  • geometry and kinematic parameters
  • steering angle and trim
  • tire cross section and trajectory in a turn
• Suspensions
  • architecture and kinematics of front and rear suspensions
  • stiffness and damping characteristics
  • determination of the reduced parameters
• Tire modelling
  • analytical models
  • semi-empirical models
  • tire-road contact forces
• Motorcycle dynamics
  • steady state rectilinear motion
  • in-plane vibration modes
  • road excitation models
  • analysis of the effects of the motorcycle response on grip/handling and rider’s comfort
  • transient rectilinear motion: acceleration and braking
  • steady turning
  • transient phases of cornering
  • gyroscopic effects
  • stability and motorcycle vibration modes
  • influence of the main design parameters on stability
  • techniques for experimental identification of the motorcycle modal parameters
  • rider-motorcycle interaction (brief introduction)

• Numerical modelling of the motorcycle dynamics
  • Lagrangian approach: stability in rectilinear motion; sensitivity analysis of the main parameters; stability in cornering; effects of structural stiffness on stability
  • modelling with commercial software: simulating maneuvers characterized by high non-linearity; simulating critical events and scenarios; simplified models for traction-control/anti-wheelie and/or anti-lock braking systems

• Experimental tests and model validation

  • experimental identification of physical parameters (mass, inertia tensor, tire characteristics, suspension characteristics, steering torque)
  • estimation of kinematic quantities
  • estimation of dynamic quantities
  • virtual tests for implementing strategies to optimize the motorcycle performance: case studies

Readings/Bibliography

The slides shown during the course will be made available for download.

Suggested books (not mandatory):

• Cossalter V. Motorcycle Dynamics. 2nd ed. LULU, 2006.
• Pacejka HB. Tire and Vehicle Dynamics. 3rd ed. Oxford, Butterworth-Heinemann. 2012.
  

Teaching methods

The course comprises:

• theoretical lectures with blackboard, PowerPoint slides and the support of multimedia tools;
• lectures and seminars held by experts from Academia and Industry;
• classroom exercises with numerical tools and simulation software.

All the contents are taught in English.

Assessment methods

Final examination on the program of the entire course. Two/three oral questions, about 10-15 minutes for each question. The candidate may be required to draw schematics and/or to write expressions/equations with pen and paper. The candidate must achieve a sufficient score (18 out of 30) for each question in order to pass the exam. The score is assigned on the basis of:

• Knowledge of the specific topic (40 %)
• Ability to analyze and discuss different scenarios and possible interactions with other topics (30 %)
• Clarity in exposition and proper use of technical terminology (30 %)

To be admitted to the exam, students must work on a group assignment (2 or 3 people), consisting in the analysis (and discussion) of a specific aspect/phenomenon of vehicle dynamics, and in writing a technical report/short scientific paper describing the activity. The use of the numerical simulation tools illustrated during the course to support the analysis is suggested but not mandatory. The document must be submitted to the Examining Committee, at least 5 working days prior to the selected exam date.

The score (18-30) is assigned on the basis of:

• Methodological approach (30 %)
• Exhaustiveness of the analysis (30 %)
• Originality (20 %)
• Clarity and document organization (20 %)

The final grade is computed as the simple average of the scores of the questions and of the assignment.

For each exam session, students that were granted the status of "working student" may ask to replace one of the dates of the session with another date. Students must contact the teacher at least 14 days before the first exam date of the session, in order to define a feasible date considering all the collected requests.

In compliance with the Art. 16 of the University Didactic Regulations, after a positive final grade has been assigned, the student can decide to retake the exam only once.

In accordance with the University Code of Ethics, students are required to adhere to the highest standards of integrity. Any activity aimed at improperly altering the outcome of examinations (e.g., cheating, plagiarism, accessing online course materials, or using unauthorized AI tools) is strictly prohibited. In particular, mere possession of unauthorized materials or devices during the examination will result in the immediate invalidation of the test and reporting to the appropriate authorities.
Any conduct in violation of these rules may lead to disciplinary proceedings or, where applicable, referral to the competent authorities if criminally relevant; in such cases, the students involved may be subject to legal prosecution.

Teaching tools

Classroom exercises with commercial software for simulating maneuvers, events, scenarios and control models.

Office hours

See the website of Alberto Martini

See the website of Marco Ezio Pezzola