4) What is state space control?
If you design, install, or troubleshoot motion control systems, you’re probably familiar with PID (proportional-integral-derivative) control, which uses feedback to detect errors between the desired position and the actual position and applies corrective commands to compensate for those errors.
Although PID control is the most common type of industrial controller, it does have limitations. First, PID control is generally not suitable for systems with multiple inputs and multiple outputs (MIMO), as the transfer functions and differential equations used to represent the system become overly complex when more then one input (or output) is involved. Second, PID control is based on constant parameters, so its effectiveness in controlling non-linear systems is limited. An alternative control method is state space control.