This document describes a tactile brush algorithm that uses apparent motion and phantom illusions to produce smooth, two-dimensional tactile strokes on the skin. The algorithm controls the frequency, intensity, velocity, and direction of tactile sensations produced by a low-resolution grid of vibrating actuators to create the illusion of high-resolution tactile motion. It utilizes apparent motion between actuators and phantom sensations from virtual actuators to generate continuous tactile motion that mimics physical brush strokes across the skin. The tactile brush algorithm provides an approach for designers to create complex, multidimensional tactile experiences using only basic tactile display hardware.

1. Tactile Brush
Drawing on Skin with a Tactile Grid Display
Chichi 10/1
Paper reading

2. Ali Israr
Haptic Researcher and Engineer
Purdue University ME PhD.
Surround Haptics
TeslaTouch
Aireal

3. What is Haptics
• Haptics is sensed all around the human body;
beyond the head/face region of the human body.
• Decoding haptic experiences are complex and
multivariate, due to wide variety of touch
receptors and perception modalities.
• Haptics is personal, affective yet delicate and
invasive.
• Sensory illusions in haptics are robust and can be
programmed.

4. Ivan Poupyrev
Master
“My job is to come up with new ideas, concepts and
research directions. Some of these ideas have become
real products, others inspired new research directions,
while many others simply satisfy my curiosity.”
--- Ivan Poupyrev

5. Ivan Poupyrev
Master

6. Tactile Brush

7. Paper Structure
• Abstract
• Introduction
• Background and Related Work
• Tactile Illusion as Design Tool
– Apparent Motion
– Phantom Sensation
• Tactile Brush
– Controlling Apparent Motion
– Controlling Phantom Sensation
– Tactile Brush Algorithm
• Evaluation
• Applications
• Conclusion

8. Abstract

9. Tactile Brush is an algorithm that produces
smooth, two-dimensional tactile moving strokes
with varying
frequency, intensity, velocity and direction of motion.

10. The design of the algorithm is derived from the results of
psychophysical investigations of two tactile illusions –
apparent tactile motion and phantom sensations.

11. Introduction

12. Research in developing tactile displays can be separated
into two broad categories:
• Design of actuation technologies and control
techniques needed to produce a microstructure of
tactile sensations
• Construction of high-order tactile percepts to
communicate complex meanings, expressions and
experiences.

13. Tactile Brush, a control algorithm that uses a
low-resolution grid of vibrating actuators to produce
high-resolution tactile strokes on skin.

14. The basic idea:
• utilize the apparent motion illusion to create tactile
motion sensation between vibrating actuators
• use phantom illusion to create virtual actuators
where no physical actuator is present.

15. The basic idea:
• utilize the apparent motion illusion to create tactile
motion sensation between vibrating actuators
• use phantom illusion to create virtual actuators
where no physical actuator is present.

16. Background and Related Work

17. Tactile Illusions as Design Tool

19. Tactile Brush

20. Two parameters
• SOA vs duration (d)
for a.
• Actuator intensities
for b.

21. Principles, definitions and challenge
• Define a moving tactile stroke as a sensation
that:
– Continuous motion
– A clear start and end
– Perceived as a single semantic unit
– Can move with varying velocity

22. Principles, definitions and challenge

23. Tactile Apparatus

24. Controlling Apparent Motion

25. Controlling Apparent Motion

26. Controlling Apparent Motion
• SOA = 0.32d + 47.3

27. Controlling Phantom Actuators

28. Controlling Phantom Actuators
• Beta = a/b

29. Tactile Brush Algorithm

30. Tactile Brush Algorithm
• Virtual Actuation Points
• Speed of Stroke and Timestamps
• Duration and SOA

31. Evaluation

32. Evaluation

33. Application

36. Conclusion

37. The Tactile Brush algorithm provides a solution
for creating two-dimensional, high-resolution,
continuous moving sensations on the surface of
the skin. Using Tactile Brush and a few off-the-
shelf tactile actuators researchers and interfaces
designers can begin creating complex and rich
multidimensional tactile experiences.

38. Q & A