Haptic Interfaces for Virtual Reality and Teleoperation
HapticsThe sensibility of the world adjacent to the body by use of the body(Gibson, 1966)
Relating to sensory information about the state of the body (including cutaneous, kinesthetic and vestibular sensations).
Pertaining to the perception of head position, acceleration and deceleration.
The feeling of motion. Relating to sensations originating in muscles, tendons and joints.
Pertaining to the skin itself as a sense organ. Includes sensations of pressure, temperature and pain.
The mechanical production of information sensed by the human kinesthetic system.
Kinesthetic Feedback Golgi tendon organs (force) Muscle Spindles (position and velocity) Experimental data ambiguous Bandwidth estimates 20-30 Hz. (Brooks, 1990)
The Cutaneous Sense
Frequency at which most easily excited(Hz)
Amplitude Threshold ((m)
Probable Sensed Correlate
Tickle, Vibration, Tap
Haptic Interfaces Constrained Motion Devices Tactile Displays
Constrained Motion Devices Force Feedback DOF constrained to portray contract.Virtual free space Virtual constraint
Device Limitations Sampling Period Device Dynamics Power Limitations
Ideal Equivalent Performance
Low Inherent Impedance Nominally displays Virtual free space. Position feedback increases impedance. High gain servos constrain motion. Limitations: Stability & power
High Inherent Impedance Nominally displays Virtual Constraint. Impedance reduced by force feedback. Framework conveys stiffness. Limitations: Dynamics & Stability
Bandwidth & The Haptic Spectrum
Temporal & Spatial Relationshipst = s v t = Temporal frequency (Hz.) s = Spatial Frequency (Cycles/m.) v = Exploration velocity (m/s).
Multi Modal Interaction HCI Occurs Using: Haptic Visual Auditory Smell ?!? Overcome limitations using other modes.