BY IRFAN AZHAR Control systems

What Do Mechatronics Engineers Do?

System Design Process

How to Design?

System Design Step 1 : State the goal e.g. control Velocity of a motor accurately. Step 2 : Identify variables to be controlled e.g. velocity of the motor Step 3 : Write Specs in terms of accuracy we must attain. o This accuracy will have the final say on the selection of sensors to measure the controlled variable. The performance specs will dictate how the closed loop should perform. The concepts of disturbance regulation, desirable responses to commands, realistic actuator signals, low sensitivities and robustness come here!

Cont…. Step 4 : Establish system configuration that results in desired system performance. It includes the sensors, actuators and the controller. Step 5 : Identify Actuators that are capable of effectively adjusting the performance of the system. Step 6 : Select a controller – e.g. a summing amplifier Step 7 : Adjust parameters to achieve the goals. Else loop back to step 4. What about Computers???

Examples: Rotating Disk Speed Control

Cont…..

Disk Control The Task : Keep the speed of disk constant in spite of motor wear and component change. The goal is to keep the actual speed in a specific percentage of desired speed. Select DC motor as an actuator because it provides speed proportional to voltage applied. Use an amplifier for the input voltage. Difference of 1 to 100 in the errors of the two systems!!!

Automated Drug Delivery

Cont….. Control Systems are utilized in biomedical field to create implanted automated drug-delivery systems for patients. In open loop drug delivery system, model of dose-effect relationship of drug is used. A drug-delivery system implanted in the body uses an open-loop system, since miniaturized glucose sensors are not yet available. The best solutions rely on individually programmable, pocket-sized in-sulin pumps that can deliver insulin according to a preset time history. More compli-cated systems will use closed-loop control for the measured blood glucose levels.

Dynamic System Modeling

Cont……

Reference The Lecture was from Modern Control Systems Book by Bishop & Richard C. Dorf.