by Tony Gonzalez
According to the National Highway Safety Administration, 3.2% of crashes attributed to the driver were the result of “…being sleepy or actually sleeping at the time of the crash.” In 2017, drowsy driving “claimed 795 lives,” and this is just one type of driver impairment.
Though no alert system will prevent all accidents, the haptic “buzz” can mitigate the risk and potentially save a life.
People unfamiliar with the word “haptic” have a working knowledge of the term through their smartphones. The “buzz” they feel when there is an alert or when they touch certain display screens is vibrotactile haptic technology at work. What people may not know is the benefits of haptics in transportation safety systems.
Traditionally, drivers have relied on their visual and auditory senses to register an “alert” in their brain from which they can take action. It only stands to reason that an additional sensory signal, tactile or kinesthetic feedback, will improve the responsiveness of the driver in certain conditions.
When integrated with safety sensors/ controllers, vibration-inducing mechanisms can alert the driver and enhance operational safety. Anywhere the driver has direct contact with the vehicle is a candidate for haptic alert technology. This includes, but is not limited to: Seats, Restraints, Steering Wheel, Accelerator Pedal, and Touch Displays. Some are small enough to incorporate into wearable technology — affording yet another option for driver sensory awareness and incorporation into aftermarket add-on safety solutions.
There are three principal types of vibration-inducing technologies:
1. Eccentric Rotating Mass (ERC)
2. Piezoelectric Actuators
3. Linear Resonant Actuator (LRA)
ERC’s are motors with an eccentric mass on the shaft. Spinning the shaft forces the unbalanced load to induce a vibration through the motor mount. The main disadvantage of this type of haptic is the inability to vary the intensity of the vibration without changing the eccentric weight’s radial location or mass.
Piezoelectric Actuators utilize a reverse “Piezoelectric effect” to generate a mechanical vibration from an applied voltage. The primary disadvantage of this vibration-inducing technology is the need for high voltages to generate a vibration that is satisfactory to register an alert.
LRA’s, however, generate vibrations through an alternating electromagnetic field — changing the shape and frequency of the input signal will vary the intensity of the vibration. This can be beneficial in generating different alerts from the same device.