Man-machine interfaces, capable of reproducing forces as user’s hand;
Accurately
On an extended frequency range
A couple of devices developed, in collaboration with the Biorobotics Lab. – UW
Direct drive motors
Optical analog position sensing to enhance resolution

PantoMouse
Panto-Mouse 3D

Interaction with virtual objects
User-designed environments
Training , games, virtual mechanisms

Rehabilitation systems
Evaluation of patient’s recovery on tailored exercises

k x
F=k•x
I=K p
•x x
F’= K f
•I
 
If K f
K p
=k  F=F’
Same perceived force!!
Virtual mechanisms haptic displays devoted to the reproduction of the touch feedback that a user would experience when interacting with a actual mechanism
Inertia, viscous friction, elasticity can be easily simulated

When playing a musical instrument, a player perceives not only the sound generated, but also the haptic interaction arising during the contact between player and instrument.
The tight correspondence between acoustic response and touch response is lost in electronic instruments, in which the sound generation is related only to the speed of the key.
Mikey (Multi-Instrument Keyboard) project:
Virtual mechanisms to simulate three different keyoperated musical instruments:
Grand piano, hammond organ, harpsichord

Mechanism composed of a dozen of parts
Hard to simulate in real time
Different “states” of the mechanism to be modeled in the dynamic simulator
Escapement
Hammer flight
Strimg-hammer impacts

Keys are driven by rotational voice coils motors (low-cost, from Hard Disk Drives)
Weights are added to account for lowest inertial term (flying hammer condition)

Each key has a reflective position sensor, read by a 44.1 kHz, 16 bits A/D
The low-cost fixed point DSP sends a current command to the motor, using a 16 bits D/A and a low-cost power amplifier
VCM
Transcond.
Amplifier
D/A, 16 bits
44.1 kHz
Key
DSP board
A/D, 16 bits
44.1 kHz
Position sensor

The dynamic simulator computes hammer position and the force to be applied to the key
The first goes to the synthesizer, the second to the motor