Lecture on Vehicle Kinematics and Dynamics

Introduction

• Lecture part of Canada Kinematic March, 4 sessions, each Tuesday at 10 a.m. Colorado time
• Focus: Vehicle damage and performance influenced by kinematics
• Upcoming sessions by Ariel Avi on kinematic software, force model, and optimization

Key Concepts in Vehicle Kinematics

• Wheelbases and Track Definition
• Scrub Radius, Mechanical Trail, Caster, and KPI Angle
  • Pickup points on the upright
  • Influence on steering dynamics
• Outboard Pickup Points
• Virtual Swing Axle, Instant Center, and Roll Center
  • Front and side view analysis

Steering and Suspension

• Steering Rack and Inboard Position
  • Influence on bump steer and Ackermann
• Spring and Anti-roll Bar Motion Ratio
• Integration with Vehicle Design
  • Decisions pre-defined for passenger cars but variable in racing
  • Considerations: inertia, circuit type, driver skills, tire characteristics, rules, vehicle weight, downforce

Vehicle Dynamics

• Formula 1 and Downforce
  • Diffuser, front wing, rear wing contributions
  • Impact of track dimensions and car width
• Wheelbase Impact on Performance
  • Short vs. long wheelbase
  • Inertia and its effect on vehicle stability and response
• Inertia Reduction Techniques
  • Example with McPherson vs. double-arm suspension

Steering Dynamics

• Caster and Mechanical Trail Effects
  • Right height, camber variation, steering wheel torque
  • Guidelines for torque levels
• Camber Variation and Steering Torque Calculations

Load Transfers and Weight Distribution

• Vertical Load Changes in Steering
  • Diagonal weight transfer impact
• Camber Variation and Tire Model Considerations

Example Scenarios and Calculations

• Infrared Temperature Sensor Usage
  • Camber adjustments using temperature data
• Steering Torque Example Calculation

Roll Center and Pitch Center

• Roll Center Altitude Effects
  • Geometric and elastic load transfer
  • Jacking forces and their effects
• Roll Center Movement
  • Transient behavior and roll center's effect on vehicle dynamics

Side View Kinematics

• Instant Center and Pitch Center Considerations
  • Influence of caster variation and pitch center location
• Anti-dive and Anti-lift Concepts
  • How they are calculated and their effects

Optimization and Practical Application

• Ackermann Steering Geometry
  • Pro, parallel, and anti-Ackermann setups
  • Calculating slip angles based on tire models
• Compliance and Steering Ratio Considerations

Final Recommendations

• Motion Ratio and Anti-roll Bar Ratio
  • Importance of correct calculation and application
• Integration Challenges
  • Kinematic decisions impacting chassis and suspension design
• Future Sessions
  • Ariel Avi to cover kinematic software and optimization

Conclusion

• Kinematics are crucial in vehicle design, impacting various dynamics and performance criteria.
• Emphasis on understanding compliance, motion ratios, and proper integration of kinematic principles in vehicle design.
• Upcoming seminars and further learning opportunities highlighted.

These notes summarize the lecture's key points, providing an overview of vehicle kinematics and dynamics as discussed in the session. They are structured to help review and understand the critical aspects of vehicle design influenced by kinematics.