A lot of modern control systems are digital because its cheaper and easier to configure.
Analog Controllers
Pros
- Infinite resolution (always working in continuous time)
- No computational delays
- Allows for exact realization of controller
Cons
- Fixed control design
- Hardware requires maintenance
- Hardware can become obselete
Digital Controllers
Pros
- Variable control design
- Complex controllers possible and cheap
- No nonlinearities due to physics
- More reliable
Cons
- Sampling/computational issues
- Potentially more complex to analyze/design
- Works in discrete time