Dynamic Systems Lab 3: System Identification with Experimentally Acquired Data, Lab Reports of Mechanical Engineering

Download Dynamic Systems Lab 3: System Identification with Experimentally Acquired Data and more Lab Reports Mechanical Engineering in PDF only on Docsity! MEM 351 Dynamic Systems Lab 3 Hands-on Lab 3 System Identification with Experimentally Acquired Data Recall that the course objective is to control the angle, rise time and overshoot of a suspended motor-prop. Towards this, the two previous labs provided the software and hardware foundations for writing LabVIEW programs and both generating and acquiring voltage signals. This lab fulfills our next step – to identify the system’s underlying dynamics. The resulting data will be used in future labs to design a suitable control system. Three concepts will be covered: Reading optical encoders with a counter, writing acquired data to a file that can be displayed in Excel, and programming a derivative function. Concept 1: Timers and Counters (Optical Encoders) The USB-6211 features counters that can be used to read optical encoders interfaced to the NI- DAQ card. A counter will be configured to monitor the optical encoder mounted on the pendulum’s shaft (see Figures A and B). The net result is the pendulum’s angle can be displayed in real-time. Optical Encoder Motor-prop Pendulum Figure A: Pendulum Setup Figure B: US Digital Inc. Encoder (with pin out) Step 1: Launch LabVIEW to create the following (very simple) front panel (Figure 1). NB: the text box should fit 8 digits Figure 1: Front panel to display real-time optical encoder degrees © Copyright Paul Oh MEM 351 Dynamic Systems Lab 3 Step 2: Start the following block diagram with a while loop. Figure 2: Block diagram for displaying encoder angle. Step 3: Complete the block diagram by adding the DAQ Assistant control. Right Click – Measurement I/O – NIDAQmx - DAQ Assist will bring up the screen (Figure 3A). Choose Acquire Signals and then select Counter Input – Position - Angular. Figure 3A: Choose Position - Angular © Copyright Paul Oh