ISO 11838:1997/Amd 1:2011

Overview

ISO 11838:1997/Amd 1:2011 is an international standard amendment specifically focusing on the kinematics vocabulary of motorcycles and motorcycle riders. Issued by the International Organization for Standardization (ISO), this amendment updates and refines terms related to the motion and forces acting on motorcycles and riders during operation. The document is crucial for professionals involved in motorcycle dynamics research, design, safety analysis, and regulations.

The amendment clarifies definitions of angular velocities, forces, and resultant motions to create a consistent language for describing motorcycle-rider kinematics. This ensures improved communication and understanding across engineering, manufacturing, and testing domains worldwide.

Key Topics

This ISO amendment emphasizes precise terminology related to motorcycle kinematics, including:

• Steering velocity: Defined as the angular velocity of the sprung portion of the steering assembly about the z-axis, providing a standard reference for measuring steering dynamics.

• Braking force: Recast as the negative tyre longitudinal force caused by applied braking torque along the x-direction, key for evaluating braking performance and safety systems.

• Conicity force: A lateral tyre force that maintains direction irrespective of rotational changes when slip and camber angles are zero, important in understanding tyre behavior and stability.

• Plysteer force: A lateral tyre force that reverses sign with changes in rotation direction under zero slip and camber angles, essential for tyre construction analysis and vehicle response.

• Resultant roll angles: Defined as angles between the motorcycle-rider center of gravity planes and the z-axis, categorized into conventional, geometrical, and effective roll angles to analyze lean and balance during riding.

• Roll velocity (Bank velocity): Specifies angular velocities about different x-axis references (conventional, geometrical, and effective), critical for modeling motorcycle tilt and rider control.

These refined definitions contribute to a more rigorous scientific framework, supporting comprehensive kinematic analyses and simulations.

Applications

The ISO 11838:1997/Amd 1:2011 amendment has broad practical value in multiple areas:

• Motorcycle design and engineering: Standardized vocabulary enables precise communication during product development, helping engineers optimize steering, braking, and handling characteristics.

• Safety and crash analysis: Clear kinematic terms facilitate the development of advanced rider assistance systems and better accident reconstruction methodologies.

• Vehicle dynamics research: Researchers can utilize these definitions to model motorcycle and rider interactions more accurately, improving stability control algorithms.

• Testing and certification: Regulatory bodies and test laboratories adopt consistent terms, ensuring reliable performance verification and compliance with safety standards.

• Education and training: Instructors and students in automotive and transportation courses benefit from a unified technical language for motorcycle kinematics.

Related Standards

ISO 11838:1997/Amd 1:2011 complements other global standards related to motorcycle safety and performance, including:

• ISO/TC 22 series: Covering various road vehicle standards, including specifications for motorcycles.

• ISO/IEC Directives: Providing structural rules for preparing consistent international standards.

• Other kinematic and dynamic standards: Such as those addressing tire performance, vehicle stability, and rider ergonomics.

Employing ISO 11838 alongside these related standards helps ensure coherent development and assessment processes in the motorcycle industry.

Keywords: ISO 11838:1997/Amd 1:2011, motorcycle kinematics, motorcycle rider dynamics, steering velocity, braking force, conicity force, plysteer force, resultant roll angle, roll velocity, motorcycle standard vocabulary, ISO motorcycle standards, motorcycle safety, vehicle dynamics, motorcycle engineering, motorcycle testing.