What Is Haptic Feedback?
Posted on November 7, 2022 by Peter Shull
Haptic feedback is the feeling of touch to relay information to users. Haptic feedback leverages haptics - the sense of touch felt in skin felt through an external interface. Though researchers have been studying haptics for decades, not until 2018 did it become popular and widespread enough that the term haptics officially entered the dictionary.
Those are the basics. Now, let’s take a deeper look at:
How does human skin detect haptic touch?
Human skin is embedded with thousands of tiny mechanoreceptors for detecting haptic touch sensations. There are 4 main types of mechanoreceptors: Pacinian corpuscles, Meissner’s corpuscles, Merkel discs, and Ruffini organs. Some mechanoreceptors, like Merkel disks and Ruffini organs, detect low frequency sensations such as skin pressure and stretch, and other mechanoreceptors, like Pacinian corpuscle detect high frequency sensations like vibration as shown in the figure at the top of this article.
Haptic feedback that vibrates the skin’s high frequency mechanorectors is typically induced via an off-centered mass DC motor or a linear actuator motor.
Off-centered mass DC motor
Linear actuator motor
How can haptic feedback train movement?
Haptic feedback can be applied to the skin to alert the user of more optimal movement patterns so as to improve rehabilitation, reduce injury risk, or for other related applications. Haptic feedback could for example be used to train someone to toe-in or increase trunk angle while walking as shown below.
Why use haptic feedback to train movement?
Here are 3 reasons to use haptic feedback to train human movement:
1) Haptic feedback intuitively trains human movement. Haptic cues applied directly to the specific body locations requiring change can naturally train movements much like the guiding touch of a physical therapist. Haptics can also be applied across multiple body locations to train simultaneous movement parameters.
2) Haptic feedback frees up visual processing. Walking, exercising, and rehabbing all typically require visual concentration. Human skin is embedded with thousands of mechanoreceptors that are largely unused during these activities making haptics a great potential fit for training movements in situations requiring visual attention.
3) Haptic feedback goes where you go. Haptic feedback is wearable, so it can be used in an infinite capture volume. It is untethered from laboratory equipment and not confined to the visible region of fixed cameras.
Find out more
From walking to running to rehabilitation, wearable haptic feedback can be used to train and improve any human movement. Check out these review papers for more extensive lists of wearable haptic feedback for diverse research and clinical applications:
[Review Paper 1 - Wearable Haptics Applications]
[Review Paper 2 - Wearable Haptics for Rehab]