Human-machine Cooperative Manipulation with Vision-based Motion Constraints - Visual Servoing via Advanced Numerical Methods - page 63

(a) (b)

Fig. 4.1 The experimental setup of the JHU SHR used to evaluate virtual fixtures to assist in
planar path following and positioning tasks: (a) macro scale; and (b) micro scale

to d Choosing d as the preferred direction of motion, we see the conditions of the

general virtual fixturing rule are satisfied.
This class of virtual fixtures has been tested at both macro and micro scales.
Results for a specific user and a wide class of compliances and situations can be
found in [1, 2]. Tests for a larger class of users can be found in [24].
We have also developed and evaluated several concrete applications of the virtual
fixture methods described in this chapter. In [22], we have applied this approach to
virtual fixture guidance to the problem of fine lead soldering for small lot electronics
manufacturing (Figure 4.3(a)). There, we show that novices improve at fine lead
soldering using virtual fixturing methods. As noted earlier, retinal surgery has been
the main focus of this work (Figure 4.3(b)). In [6], we developed a stereo vision-
based guidance system for retinal surgery, and showed improved accuracy using
virtual fixtures. Finally, we have also investigated modifications of the virtual fixture

.

Fig. 4.2 Endoscopic image
of the 80

m-diameter
human hair used as the path
in micro scale experiments

μ