Page 148 - Flexible Robotics in Medicine

134 Chapter 5

Figure 5.27
Graph of disturbed longitudinal displacement (1.59 6 0.16 cm) against time.

would be inconsistencies in the detected points, which would affect the accuracy of the
displacement measurement.

Dynamic stability in lateral direction This experiment was conducted in order to determine the
dynamic stability, which can be defined as the property of the prototype that causes it to
damp the oscillations. A rightward force was exerted on the prototype, and the dampening
effect was observed by measuring the lateral displacement over time. The stabilization time,
which was the time taken for the lateral displacement to decrease to a constant value, was
measured. The prototype was stable when the lateral displacement was nearly constant.

Fig. 5.28 illustrates a gradual decrease in the amplitude of the lateral displacement. The
approximate time taken to stabilize was around 0.63 seconds in this case. We observed an
underdamped system as the system oscillated with the reduced frequency with the
amplitude gradually decreasing toward zero. Since this will not be the main plane of motion
of the prototype upon actuation, a stabilization time less than 1 seconds can be considered
as acceptable.

Dynamic stability in longitudinal direction The objective of this experiment was to measure the
longitudinal displacement of the prototype’s tip when subjected to upward and downward
force and was conducted in two phases, namely before and after actuation.

The prototype was tightly secured in the clamp to provide a static platform to reduce the
risk of inaccuracy. The upward and downward force was provided by means of a hand
flick. The objective was to show an upward displacement when subjected to an upward
force and a downward displacement when subjected to a downward force. By subjecting a