Fundamentals of Steering Systems
I.D. # C0716 Duration 3 Days

Design and development of a modern steering system influences vehicle response to steering wheel input, driver effort, comfort, safety and fuel economy. In this interactive seminar participants will analyze the steering system from the road wheel to the steering wheel.

Day one will begin with a deep dive into the anatomy and architecture of the lower steering system (wheel end, suspension geometry, linkages and steering gear), its effect on vehicle response and how forces and moments at the contact patch are converted to a torque at the pinion. Next, the anatomy and architecture of the upper steering system (steering column and intermediate shaft) will be explored as well as the role of the upper steering in the occupant protection system, steering non-uniformity, and how torque and angle at the pinion is converted to torque and angle at the steering wheel.

Day two will be devoted to the anatomy, architecture and function of electric power assisted steering systems. Hydraulic and electro hydraulic power steering systems will be briefly discussed, with additional detailed information provided in the course handout.

Day three will begin with a discussion of common steering objective tests and how system design and tuning affect steering response, torque feedback and error state performance. The seminar will conclude with a discussion of advanced steering systems such as rear wheel steer, active front steer, active park assist and other driver assistance systems.

Students will have the opportunity to participate in exercises throughout the seminar with the objective of calculating a power steering assist curve for an electric power steering system. Many physical parts will be available for the students to examine.

This course has been approved by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR) for 12 Continuing Education Units (CEUs). Upon completion of this seminar, accredited reconstructionists should mail a copy of their course certificate and the $5 student CEU fee to ACTAR, PO Box 1493, North Platte, NE 69103.

Learning Objectives
By attending this seminar, you will be able to:
  • Identify common steering and suspension system architectures
  • Compare and contrast different types of steering gears
  • Describe the function of the steering column and intermediate shaft subsystem
  • Describe the influence of system tuning on steering response and torque feedback
  • Compare and contrast different types of power assist systems
  • Describe the effect of power steering on fuel economy
  • Calculate important parameters that affect steering response and torque feedback
  • Describe some of the features of advanced steering systems

Who Should Attend
This seminar is designed for automotive engineers in the vehicle dynamics, chassis, suspension, steering and chassis controls fields who work in product design, development, testing, simulation or research.
Participants must have a working knowledge of the fundamentals of vehicle dynamics acquired through sufficient work experience or by participating in seminars such as SAE's Vehicle Dynamics for Passenger Cars and Light Trucks (ID# 99020), Chassis and Suspension Component Design for Passenger Cars and Light Trucks (ID# 95025) or Advanced Vehicle Dynamics for Passenger Cars and Light Trucks (ID# C0415).
Seminar Content
  • Introduction
    • Elements of the steering system
    • Coordinate systems
  • The Lower Steering System
    • Kingpin axis -- Front versus rear steer; Caster angle and kingpin inclination; Caster trail and scrub radius; Steer arm
    • Class exercise - Calculate moment about the kingpin axis for cornering and parking loadcases
    • Linkages/steering geometry -- Rack and pinion; Haltenberger; Parallel linkage
    • Steering gear anatomy and architecture -- Rack and pinion; Recirculating ball
    • Friction and compliances
    • Class exercise - Calculate pinion torque for cornering and parking loadcases
  • The Upper Steering System (steering column & intermediate shaft)
    • Anatomy and architecture
    • Non- uniformity
    • Sources of friction and torsional compliance
    • Role of the upper steering system in the occupant protection system
  • Power Assist Systems
    • Overview of hydraulic, electro hydraulic and electric power steering systems
    • Electric power assisted steering column, pinion, dual pinion, concentric drive and belt drive systems)
    • Class exercise - Calculate a power steering assist curve for an electric power assisted steering system
  • The effect of steering system design and tuning parameters on vehicle level performance
    • Low speed maneuverability
    • High speed on-center steering response and torque feedback
    • High speed cornering response and torque feedback
    • Error states (nibble/wheelfight, pull/drift)
  • Advanced Steering Systems
    • Active Park Assist
    • Active Front Steer
    • Driver assistance features
    • Active rear wheel steer

Instructor(s): Timothy Drotar
Timothy Drotar is currently a senior staff engineer in vehicle dynamics at Tesla. Prior to joining Tesla, he spent 30 years at Ford Motor Company where he specialized in chassis systems and vehicle dynamics for passenger cars and light trucks. Tim is a member of SAE, SCCA and The Tire Society. He holds a B.S. in Mechanical Engineering from Lawrence Technological University and a M.S. in Mechanical Engineering from the University of Michigan-Dearborn.

"Very informative... Many hours of research saved by attending this course. "

Newton Montano


Trams International

"This class provides a great starting point and gets into enough detail for most non-designers. "

Jared Sebree

Engineering Coordinator

Honda of America MFG

"Tim provides a very thorough overview of common steering systems in a practical, easy to understand, hands on manner. "

Phil Kling

Manager, Product Investigations

General Motors of Canada LTD

"Very informative class on everything that goes into designing a steering system from the ground up."

Cory C. Cousineau

Development Engineer

EMP-Engineered Machined Products, Inc.

Fees: $1699 SAE Members: $1529