Engineering models codec review
Suppose we consider any departure less than 15 minutes late acceptable to
customers. What percentage of Delta flights departed less than 15 minutes late?
> DL_Flights = find(strcmp(F.Carrier,DL');
> OnTime = sum(F.Delay(DL_

Engineering models links review
Substitute in the values for link lengths and desired gripper position using subs:
> L1 = 3; L2 = 2; x = 2.4; y = 3.2;
> f1 = subs(f1)
f1 =
12/5 = 2*cos(Th1 + Th2) + 3*cos(Th1)
> f2 = subs(f2)
f2 =
16/5 = 2*sin(Th1 + Th2) +

Engineering Models expressions review
Symbolic Expressions
The Subs Function
Example of Subs
> f = sym('2*x^2+4*x+5')
f = 2*x^2 + 4*x + 5
> x = 3; result = subs(f)
result = 35
% Plugs in 3 for x, result is a symbolic constant
> x = 1:10; result = subs(f

Engineering models common error review
Common Error
Suppose we want to locate all of the Frontier flights that left on 11/23/13.
Dont split the two conditions like this:
> carrier_loc = find(strcmp(F.Carrier,'F9')
carrier_loc =
390
391
392
393
394
395
39

Engineering Models possible solution review
Two possible solutions:
Th1 = 82.0851o and Th2 = -75.5225o
Th1 = 24.1751o and Th2 = 75.5225o
Verify Results?
> x = L1*cosd(Th1(1) + L2*cosd(Th1(1)+Th2(1)
x = 2.4000
> y = L1*sind(Th1(1) + L2*sind(Th1(1)+Th2(1)
y

Engineering Models quiz 1 review
Using Symbolic Toolbox for
Trig Functions
Caution: When using symbolic toolbox for trig functions, always use the radian
functions (sin, cos, tan ). You cannot use the degree functions (cosd, sind, tand).
> f = sym('tand(

Engineering models understanding review
Test Your Understanding
Take the quiz at end of Video A
The Solve Function
Examples of Solve
> f1 = sym('P*V = n*R*T')
f1 =
P*V = R*T*n
> T = solve(f1,'T')
T = (P*V)/(R*n)
> P = solve(f1,'P')
P = (R*T*n)/V
> n =

Engineering models symbolic review
Symbolic Variables
The following variables can create difficulty in some of the symbolic toolbox
functions. Dont use them!
I and i
E and e
D
Any variable name that starts with the letters: th
For example: theta, th1, tha

Engineering models robot review
Two link robot arm
Define a coordinate system by designating the base of the arm to be the
origin (0,0)
What are the x and y coordinates of the joint and the end (gripper) in terms
of the lengths of the links and the angles