Fig. 5From: Stable haptic feedback generation for mid-air gesture interactions: a hidden Markov model-based motion synthesis approachWaveforms for vibrotactile actuator during gesture execution. Waveforms for vibrotactile actuator. a Haptic spring mode: the amplitude of the vibrotactile waveform increases with dragging or zoom distance (Concurrent feedback). b Haptic impulse mode: Asymptotically decreasing sinusoidal waveform at the end of tapping gesture whose amplitude corresponds to hitting speed (Terminal feedback)Back to article page