Simulink/Simscape Exercises for Module EG7010

Question 1: Spring and dampers: series and parallel Construction

The following four exercises are the assessment for the Simulink/Simscape part of this module. Together they represent 20% of the mark for this module. Each question carries 5%. Before answering them, you should make sure you have completed the onramp courses for Simulink and for Simscape. Answers are expected for all four questions. You should create a Word document to act as a log-book and put your answers to the questions, graphical and numerical outputs and any other observations in it. Please put all four answers in one document. This should be converted to a pdf file when complete and put in a directory containing the final .slx files you have made for this assessment and nothing else. Then zip the directory up and upload it to Assessments tab of the EG7010 Blackboard site by 4pm on 17/12/2021. Late entries will be subject to the usual mark deductions. If software problems prevent you from completing the answers, please include details, such as error messages in the pdf file. Q1 Spring and dampers: series and parallel Construction Create a mass-spring-damper system in Simscape. Start with a 1kg weight attached to a fixed reference point. Between these two elements and in series with them, should be a subsystem consisting of a spring of spring constant k = 100 N/m in parallel with a damper of coefficient c = 1N/(m/s). A translational motion sensor should track the position of the mass, using a scope and an ideal force source should provide an additional force of 5N, switched on using a Simulink step block. Like all Simscape models, it should have a Solver Configuration block. Experiments a. Run the model and from the graph produced, verify in your log-book that the expected displacement is seen. Use Tools/Measurements to place horizontal cursor lines on this graph at the level of maximum displacement and at the level which is half way between this level and the final resting level. Choose File/Print from the Scope window to save this as a Matlab figure or a pdf for future reference. Show this figure in your report. b. Copy and paste (Ctrl-C and Ctrl-V) the spring and place the new spring in series with the old one, so they are still in parallel with the damper, as shown in figure 1.1. Run the simulation again and comment on how the graph has changed qualitatively. In particular, notice the final resting level and the period of oscillation. There is no need to show the figure in your report. c. Now erase the extra spring and instead, put it in parallel with the spring-damper subsystem, as shown in Figure 1.2. Run the simulation again and comment on how the graph has changed qualitatively. Figure 1.1 Figure 1.2 d. Now erase the extra spring and do the same two exercises (b and c) with the damper. For these, you should comment on the following question: ‘Compared to exercise 1a, are there more or fewer oscillations between the times when the system reaches its maximum displacement (horizontal cursor 1) and when the amplitude of the oscillation has died away to half of that value (horizontal cursor 2)?’ Comment on your result. e. Now copy and paste the entire spring-damper subsystem and put the new spring-damper subsystem in series with the original one. Let’s call this output 1. Now, going back to the original system with one spring and one damper in parallel, change the values of k and c until you get the same graphical output as output 1. State what values of k and c you u