Vehicle Passenger Safety: Exploring Whiplash Protection Systems

Objectives Achieved Quantify head motion using video analysis.  Discover how mass and stiffness affect head displacement.  Relate to motions that occur in automobile collisions: female occupants have larger motions and greater incidence of injury.

Objectives Achieved Design of an active head restraint.  Discover how geometry may be used to effectively produce linear motions from angular shaft rotations.  Meet specifications using different designs.

Objectives Achieved Characterization of motor response.  Discover how different commands affect the rotation of the motor.

Objectives Achieved Improved sensor performance.  Discover how prediction of a collision can improve the ability to protect the head.

Objectives Achieved Integrated system response.  Discover how the properties of individual elements of a system (head-neck, sensor, motor and head restraint) contribute to the entire system response.

Limitations of the System/Process Video motion analysis Head-neck model Lego system (hardware, motor, sensors) Others…? (Students brainstorm)

Limitations of the System/Process Video motion analysis Observations at discrete time points (dependent on camera frame rate); may miss the collision or peak displacement . Blurry images due to movement. Variability in marking images.

Limitations of the System/Process Head-neck model Does not represent individual anatomical structures; cannot determine if or where injury occurs. Too flexible? Variability in model components.

Limitations of the System/Process Lego system Limited ways to attach pieces. Motor overshoot. Touch sensor does not allow enough time for head restraint to move appropriately.

Real World Application Whiplash is estimated to affect approximately 800,000 people annually in the U.S., with an economic cost of $2.7 billion per year. (National Highway Traffic Safety Administration, 2004) Approximately 15-40% of patients with whiplash injury develop long-term neck pain. (Barnsley et al., Pain, 1994)

Real World Application Current head restraints Provides protection even for those who do not adjust head restraints properly. Moves in a horizontal and upward direction.

Real World Application Most are body-activated: Mechanically activated by the body weight of the occupant on the seatback (lever action)

Real World Application Some are sensor-activated: Sensors such as those used by airbag control; electromechanical or pyrotechnical release of head restraint.

Discussion Questions What are some other automotive safety devices developed by engineers? Seat belts Air bags “Crumple zones” “Smart Car” that senses impending collision and applies brakes

Discussion Questions What do you need to know when designing safety devices for automobiles? What do you need to know to design physical models (dummies) for safety testing?