Page 347 - Flexible Robotics in Medicine

338 Chapter 14

Jerk error
Speed
curve

Error tracking
curve

Time (ms)

Figure 14.10
Sample graph from the QZ driver debugger.

Table 14.3: Table of corresponding keyboard inputs and output effect.

Keyboard
input Effect on motor Effect on concentric tubes
F Motor 1: Anticlockwise rotation of the outer concentric tube
clockwise
R Motor 1: Clockwise rotation of the outer concentric tube
anticlockwise
D Motor 2: Upward movement of the upper column, forward movement of outer
clockwise concentric tube
E Motor 2: Downward movement of the upper column, the backward movement of
anticlockwise outer concentric tube
S Motor 3: Clockwise rotation of the inner concentric tube
anticlockwise
W Motor 3: Anticlockwise rotation of the inner concentric tube
clockwise
A Motor 4: Downward movement of the lower column, the backward movement of
anticlockwise the inner tube
Q Motor 4: Upward movement of lower column, forward movement of the inner
clockwise tube

The control software was written in Python, utilizing multiple threads to control the motor
drivers simultaneously and to perform kinematic calculations in real time. Two modes of
control were developed: user control and preprogrammed state control. In the first mode,
the keyboard was utilized for easy prototyping and debugging of the control software.
Table 14.3 details the control scheme of the concentric tubes.

In preprogrammed state control, the CTR could be programmed to steer itself independent
of user control.