Game Development Reference
In-Depth Information
Figure 8.6 PHANToMr Premium 1.0 and 1.5/6DOF Haptic Devices. (Illustration: SensableTechnologies
Inc., with permission)
which prioritised sensitivity to a high force capacity, although it was restricted to three
motorised degrees of freedom (force feedback on translations alone). In the meantime,
the other laboratories were mostly working on interfaces that admittedly provided
a more enhanced interaction with six degrees of freedom with force feedback (force
feedback and torque feedback on translations and rotations) but at the cost of greater
complexity which would generally result in lesser transparency.
The first PHANToMmodels (1.0, 1.5 and 3.0 models of the Premium series) have
work spaces that respectively allow movements of the hand, forearm and the arm. A
version featuring six degrees of freedomwith force feedback appeared later towards the
end of the 90's to meet the requirements of some users (Chen, 1999). This version was
available in two sizes (1.5 6DOF and 3.0 6DOF). Finally, a version providing higher
force feedback was offered (1.5 High Force and 1.5 6DOF High Force) in 2004. The
specifications of these interfaces can be downloaded from www.sensable.com.
At the same time, Sensable Technologies developed a 3D carving and modelling
software package for industrial design applications, which made digital prototyping
possible. The development of this software was accompanied by the development of
interfaces that were more compact, less expensive and easier to use, which could be
easily installed on a personal computer as well as a desktop. The first of its kind, the
PHANToM Desktop, was launched in the market in 2000, followed by PHANToM
Omni in 2004. All these interfaces use a structure constituting a serial parallelogram
with a pivot linkage for the translations and a ball joint formed by three concurrent
pivot connections for the rotations. This simple solution helps to place the three motors
providing the force feedback near the base, which limits the apparent inertia. The use
of capstan reducers also helps to obtain high transparency. The torque feedback on
the 6DOF versions is provided by mini motoreducers placed at the level of the wrist
of the robot. This solution is simple and compact. However, the force feedback in
rotation is limited and of lesser quality. The Desktop versions and especially Omni
are more competitive. They use more standard components that help to offer better
market products. This is however at the cost of a reduction in the force capacity and
lower transparency (higher friction and lower stiffness).
Search Nedrilad ::




Custom Search