Lab Activities
General Lab Materials and Policies
This course requires completing several laboratory activities that demonstate the theory of control systems and measurement. These activities include both contructing hardware circuits and system simulations and analysis using software.
Course lab activities utilizes circuit simulation software distributed by Cadence Design Systems and block diagram control simulation using MatLAB/Simulink by MathWorks. Cadance Design provides a student version of the OrCad PCB Designer Lite software is available from this site. This software is a suite of software packages that provide Pspice circuit simulation and printed circuit board design capabilities. The lite version has limitations, but they will not imped use in this course.
The MatLAB/Simulink software by MathWorks Inc. allows users to perform engineering calculations and create block diagrams based on physical systems. The software computes the response of the modeled system in both time and frquency domains. Student versions of this software are available. Follow this link to access the MathWorks site.
MatLab Tutorial Materials
MatLAB software is a powerful computational tool for engineering analysis. It combines with Simulink to provide a graphical control system analysis tool. The links in this section lead to documents and videos that help you learn to use these software tools to perform calculations, produce graphs and analyze control system performance in time and frequency domains.
The first two links in this section lead to printed documentation that introduces the basics of programming using the MatLAB environment and gives an abridged listing of some of the functions defined for compute control systems responses.
The next set of links lead to video presentations that demonstrate how to use the MatLAB programming environment. This first video demonstrate how to navigate, enter variables, and perform simple calculations using MatLAB. Following videos show how to use MatLAB to plot the results of computations onto x-y graphs. These videos present both single and multiple plots on the same axis. The next video show how to use MatLAB commands to perform control system calculations.
The next tutorial video show how to create a linear time-invarient (LTI) system block. This is the MatLAB equivalent of a transfer function. This structure couples with analysis functions allowing users to compute the response of a control system using time-based inputs like step functions or variable frequency sine inputs.
The scripting video shows how to enter MatLAB instructions into a text file allowing the resulting file to be executed like any programming application. The final video shows how to compute resp
The final video demonstrates how to covert a transfer function into a LTI system that can be analyized for time and frequency response. The demonstration shows how to produce time response to a step input function and interpretate resulting plot. The frequency response analysis produces Bode plots that indicate the stability of the modelled control system
Laboratory Activities
Activity 1: Analog Sensor Signal Conditioning
Use analog OP AMP circuits to scale the output of a sensor to signal levels commonly found in practical control systems. To use OP AMP analog circuits to combine several simulated sensor inputs according to a predefined input signal formula. Produce an error signal using an OP AMP differential amplifier. Estimated Completition Time: 6-7 hours
The lab videos guide you through the design of of scalar circuits using OP AMPs, Averaging circuits, and implementing the summation symbol in block diagrams using a Difference amplifier. The LM 741 OP AMP can implement all these functions when used in the appropriate circuit. The final video shows how to simulate the sensor inputs using potentiometers.
Activity 2: Proportional Control Action
In this laboratory activity you will construct a proportional controller using OP AMPs to implement a proportional controller. This is the simplest mode of control. The proportional controller amplifiers the error between the desired and measured values to produce the system correction. mode of feedback control. Estimated Completition Time: 6-7 hours
You will measure the steady-state error of the system for various controller gain values and also observe the transient response to rapidly changing inputs. This lab also introduces the RC time constant as a representation of any first-order process.
The Lab 2 videos give step-by-step demonstrations on how to design the feedback system. This includes the summing block, the control and the RC circuit that represents the first-order process under control. The videos include student results video for system time response.
Activity 3: Introduction to Control System Modelling with Matlab/Simulink
This laboratory introduces the Matlab/Simulink programming and numerical simulation software. Learn how to generate frequency response and time plot common to control systems analysis and design. These include Bode plots and unit step response. Create basic open loop and closed loop block diagram systems using Simulink and find their response using numerical methods that plot the response as graphs. Estimated Completition Time: 2-3 hours.
The lab videos show how to use the Simulink graphical control system simulation tool.
Activity 4: Modeling Control Systems Using Matlab/Simulink
This lab uses Matlab/Simulink software to model an antenna positioning system. Students develop the transfer function blocks from component parameters and construct the block diagram in Simulink. Observe the results of step input changes and external disturbances on the control performance using various types of control action. Estimated Completition Time: 3-4 hours.
The lab videos demonstrate more features of the Simulink analysis system. The videos demonstrate how to construct conplex inputs using ramp and unit step inputs. The MATLAB script file processes the results of Simulink plots providing greater analysis capabilities and the ability to cut and paste results to other applications, such as MS Word. Click on the link and save the file for use in this lab.
Activity 5: Motor-Generator Speed Control Using Proportional and Proportional/Integral Controllers
In this lab you will design and test a feedback control system that regulates the speed of a motor generator system. A dc tachogenerator measures the speed of the motor-generator system. Build a proportional controller using OP AMPs to control the motor speed as the generator load changes. Design a proportional-integral controller using OP AMPs. Compare the performance of the two systems. This lab will use a pulse width modulated dc voltage source produced with a LM 555 timer, high speed OP AMPs and a voltage comparator. The controller output is the control voltage for the variable voltage source produced by the pulse width modulator.
Estimated Completition Time: 8-10 hours.