- Note This Pre Lab Exercises Serve The Purpose Of Familiarizing You With The Vis Sim Software Which You Will Be Using F 1 (86.88 KiB) Viewed 46 times
Note: This pre-lab exercises serve the purpose of familiarizing you with the Vis Sim software, which you will be using for the lab exercises. Introduction to Vis Sim/Embedded Controls Developer VisSim/Embedded Controls Developer is a visual environment for model-based development of embedded systems. Using VisSim/Embedded Controls Developer, it is easy to create working models of your control and system under control. Vis Sim is a block diagram language for creating complex nonlinear dynamic systems. To create a model, simply drag blocks in the workspace and connect them with wires. Then click the Go button to initiate your simulation. The response is instantaneous. By combining the simplicity and clarity of a block diagram interface with a high- performance mathematical engine, VisSim provides fast and accurate solutions for linear, nonlinear, continuous time, discrete time, SISO, MIMO, multi-rate, and hybrid systems. With VisSim's wide selection of block operations and expression handling, complex systems can be quickly entered into VisSim. Using VisSim, step response, system dynamic and etc will be plotted automatically. Furthermore, this will simplify analysis and design of a control system. The main objective of this lab exercise is to introducing VisSim to students so that students will be able to use VisSim to simulate and get better idea about transient response from a control block diagram. The Vis Sim Environment VisSim's user interface consists of the basic elements, illustrated in Figure 1 below.
The Vis Sim Environment VisSim's user interface consists of the basic elements, illustrated in Figure 1 below. De Vi Qu Block diagram window Standard toolbar Block diagram toolbar Figure 1 Advog wedne BARCLAY DOHODNOTENY CE•CTU@C OOODCOCHODE DEOSEDCOO SCUERPOO 5 7.5 10 125 15 175 ( 130 50X The visSim Environment Work place window
Constructing a general control system block diagram To create a new block diagram, click the left mouse button to select the desire block diagram either on block diagram toolbar or block diagram window. Below are some of the common block diagram which often used in control system. i.) • Tranfer function - executes a single-input single-output linear transfer function To create transfer function, click Blocks > Linear System ->transferFunction on the block diagram window then drag the block into the workplace. Double click on transfer function block then set Polynomial coefficients (Transfer function). A transfer function ii.) n(s) d(s) is characterized by the numerator n(s) and denominator d(s). For example 25³ +165 +4 G(s)= 10s +225 +45² +2 G(s) Polynomial Coefficients Numerator : 2 Denominator : 10 0 0 = 16 4 22 4 2 • Gain - multiplies the input signal by the gain amount i.) To create gain, click Blocks -> Arithmetic -> gain on the block diagram window then drag the block into the workplace. ii.) Double click on the gain block then set the desire Gain value.
• i.) ii.) I.) II.) Gain - multiplies the input signal by the gain amount To create gain, click Blocks > Arithmetic -> gain on the block diagram window then drag the block into the workplace. Double click on the gain block then set the desire Gain value. ii.) Summing Junction - produces the sum of two signed input signals To create summing junction, click Blocks -> Arithmetic-> summingJunction on the block diagram window then drag the block into the workplace. The sign of the input signals can be toggle(switch from positive to negative and vice versa) by holding down the CTRL key and clicking the right mouse button over the connector tab. . i.) ii.) i.) • Plot - displays simulation data graphically in customizable plots To create summing junction, click Blocks > Signal Consumer -> plot on the block diagram window then drag the block into the workplace. By default, the plot will show simulation time start at Osec and end at 4sec. To change simulation time, click simulation at menu bar then select simulation properties change the desire simulation start and end time. Step input - creates a unit step signal To create summing junction, click Blocks > Signal Producer →> step on the block diagram window then drag the block into the workplace. Double click on the step input block to change the amplitude of the step input
Robotic arms are commonly used especially in the heavy industry such as automobile manufacturing factory. Along the production line, one of the robotic arm is required to have a bandwidth of at least 1 Hz and a phase margin (PM) of 45°. The system is with the process transfer function as shown below in Figure 5: R(s) K Phase compensator Figure 5: Robotic arm control system. Y(s) Required Tasks 1. Determine a suitable value for the gain, K, and suggest a suitable phase compensator, G.(s). 2. Justify your suggestion of the phase compensator. 3. Obtain the transfer function for the phase compensator by using VisSim simulator software. Design Procedure The general procedures for designing a phase compensator is given below: 1. Determine the gain, K, to satisfy the requirement such as the steady state error tolerance and the bandwidth needed. 2. Construct Bode plot and measure the PM. 3. Determine the values of a and ... Refer unit materials for the choice of phase compensator. 4. Calculate the frequency at which the maximum phase lead to be located, w.. 5. Calculate the T value. 6. Substitute the a and T values into the phase compensator transfer function. 7. Redraw the Bode plot and check if the PM fulfil the requirement. If not, the procedures are repeated by appropriate adjustment to the gain, K, and phase allowance of the *.