Introduction for CPC 1. Which of the following statements are true? (a) Feedback and feedforward control both require a measured variable. (b) The process variable to be controlled is measured in feedback control. (c) Feedforward control can be perfect in the theoretical sense that the controller can take action via the manipulated variable even while the controlled variable remains equal to its desired value. (d) Feedforward control can provide perfect control; that is, the output can be kept at its desired value, even with an imperfect process model. (e) Feedback control will always take action regardless of the accuracy of any process model that was used to design it and the source of a disturbance. 2 Consider a home heating system consisting of a natural gas-fired furnace and a thermostat. In this case the process consists of the interior space to be heated. The thermostat contains both the measuring element and the controller. The furnace is either on (heating) or off. Draw a schematic diagram for this control system. On your diagram, identify the controlled variables, manipulated variables, and disturbance variables. Be sure to include several possible sources of disturbances that can affect room temperature. 3. In addition to a thermostatically operated home heating system, identify two other feedback control systems that can be found in most residences. Describe briefly how each of them works; include sensor, actuator, and controller information. 4. Driving an automobile safely requires a large amount of individual skill. Even if not generally recognized, the driver needs an intuitive ability to utilize feedforward and feedback control methods. (a) In the process of steering a car, the objective is to keep the vehicle generally centered in the proper traffic lane. Thus, the controlled variable is some measure of that distance. If so, how is feedback control used to accomplish this objective? Identify the sensor(s), the actuator, how the appropriate control action is determined, and some likely disturbances. (b) The process of braking/accelerating an auto is highly complex, requiring the skillful use of both feedback and feedforward mechanisms to drive anfalu Fas faadhi the allu