Game Development Reference
Figure 8.7 Virtuose 3D of CEA-LIST, copyright photo E.
Joly/CEA-LIST, and Virtuose 6D 35-45.
(Illustration: Haption, with permission)
linkage), already used on the master arm of JPL C space teleoperation (McAffee &
Fiorini, 1991), is quite close to the previous one (Figure 8.8) (Avizzano et al., 2003).
Finally, the CEIT (Centro de Estudios e Investigaciones Técnicas de Gipuzkoa)
in Spain developed an interface with 6 degrees of freedom, including 3 with force
feedback, using a serial structure constituting a serial parallelogram with a slider link-
age, the Large Haptic Interface for Aeronautic Maintainability (LHIfAM), (Figure
8.9) (Borro et al., 2004). This solution helps to obtain a huge work space (Table 8.4)
but requires using a force sensor to offset the friction and inertia introduced by the
arrangement of the linkages.
220.127.116.11 The parallel structure f ixed interfaces
Some force feedback interface designers have used parallel structures instead of serial
structures. These architectures consist of several kinematic chains arranged in parallel
between the fixed base and a platform that supports the handle held by the user. In
this case, the force feedback interface has high stiffness and low inertia. Moreover, it is
possible to place the actuators directly on the fixed base or very close to it. However,
their work space is reduced, mainly in orientation, in relation to their dimensions. They
are also significantly more difficult to design and control, and often present numerous
singularities that need to be excluded from the work space.