Question 1) A servomechanism is to be designed. If a rotational potentiometer is to be used by the operator as an input mechanism for the desired angular position, and the output spindle is to be driven by a DC motor whose angular position is determined by an identical potentiometer to the one used for the input;
a) Design an analogue circuit for such a dosed loop control system, utilizing proportional control only. Explain the flown operation of your circuit and specifically in terms of Steady State Error, gain selection and stability. You may assume that the DC motor is of low power and able to nm from a supply of 3V.
b) Describe how adding integral control to this dosed loop system could aid its performance.
c) Redesign the above PI control system utilizing a microcontroller and explain your proposed solution with the aid of a System Level diagram. In particular, explain how the proportional and integral terms will be dealt with in the microcontroller and how the overall actuation voltage will be derived and delivered to the motor.
Question 2) In the context of a microcontroller based control system and with the aid of appropriate diagram:
a) Describe how the speed of a DC motor can be controlled using an N-type MOSFET.
b) Describe how the speed of a DC motor can be controlled using a power amplifier.
c) Describe two methods of how the direction of a low passer DC motor can be controlled.
d) A proportional output senor is required to be used as an elbow position amasses in a robotic arm operating in a noisy environment polluted by 50Hz electronic noise.
i. Draw a circuit diagram depicting the use of a rotational analogue potentiometer as the sensor and include any filtering components and their calculated values. Make a suggestion on the sampling frequency to be used.
ii. Draw a circuit diagram utilizing a digital incremental sensor instead of the analogue potentiometer. Describe the advantages and disadvantages of this sensor in comparison to the analogue potentiometer.