ABSTRACT
In earlier chapters, we focused on systems working in continuous mode, which implies that the system is monitored and controlled at each and every instant of time.
While analog control is quite important to understand control theory, implementing the designed controller using analog components would pose a number of problems. We will describe these issues in the following sections. In fact, as we have pointed out earlier, analog controllers are seldom implemented in modern control systems especially in robotics. They are expensive in the long run, since they need more calibration and maintenance than a digital system, due to aging of analog components. The falling price of computing hardware also makes digital controllers more attractive. They can work in most of the harsh environments where some robots are deployed. Furthermore, the distributed processing, which is very useful in robotics, is also possible to implement with digital controllers. They can fit in to small spaces and communicate with systems in the vicinity or far away. The necessary hardware or protocols for such communication network such as IEEE-488 are readily available. The instrumentation field also is moving toward digital systems. Therefore, digital controllers fit well with digital instrumentation.
