### Author Topic: Robotics Homework  (Read 2426 times)

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#### fresnedr

• Beginner
• Posts: 2
##### Robotics Homework
« on: February 14, 2015, 09:15:19 AM »
Hello,

First post here. A quick introduction, I am a junior in college looking to get a BS in Mechanical Engineering. As an elective this semester, I chose to take Intro to Mobile Robotics. The class is really interesting and I enjoy it so far.

I have gotten stuck on one of our homework assignments. The professor asked the class to do the following using Matlab:

Imagine a robot follows a circular path defined by: (x-50)^2+(y-50)^2=25^2 (meters)

Must complete the circular path in 20 seconds.

Program in Matlab to plan velocity profile for process, using point robot kinematic model.

Approximate circle as polygon with 20 sides. Find the velocity for each line segment.

Turn in code, data table, verification overlay (velocities at each point).

My Solution:

Graphing the circle in Matlab was pretty easy. The rest is where I am getting stuck. We can easily calculate the speed of the robot since we know the distance and the time that it has to travel that distance.

I am unsure what he means by the kinematic model.

If anyone could help, I would appreciate it greatly. I would ask him this Monday but his only office are after class when the homework is due(Wednesday).

#### mklrobo

• Supreme Robot
• Posts: 559
• From Dream to Design at the speed of Imagination!
##### Re: Robotics Homework
« Reply #1 on: February 14, 2015, 11:17:52 AM »
Hello!
I would offer an opinion.
The  kinematic model, to my recollection, is the calculation
of Centros and accelerations about a mechanisim. To make a
kinematic model of a robot, would take a free body diagram,
and calculate the forces involved in the robot. Ks, Kd are variables
that are used in calculating the power of movement.
To use this as an inference, maybe the acceleration from the middle
of the circle
?
If he desires to know the work, or power used, that would entail the
weight moved in the time allotted; which translated to power from the
motor to the wheels for the work by the motor.
I would go to the library to look for a similar problem presented;
specifically, REA's problem solvers series. Mechanics, statics, and physics
are the subjects to look into. Undoubtedly, this problem is based on other
similar problem. The problem solvers series has ALOT of solved problems
which may aid you in navigating to a reasonable solution.
Good Luck!...

#### fresnedr

• Beginner
• Posts: 2
##### Re: Robotics Homework
« Reply #2 on: February 17, 2015, 07:05:49 PM »
Thank you for your suggestion.

The part of the lecture that was taught and is expected to be used for this homework assignment is shown in the last few pages of this PDF.

I think I got it mainly, it's just the MATLAB coding that I'm getting stuck on.

I want the program to compute the values for 20 steps from 0 to 2pi.

I am having trouble getting the for loop to work.

#### mklrobo

• Supreme Robot
• Posts: 559
• From Dream to Design at the speed of Imagination!
##### Re: Robotics Homework
« Reply #3 on: February 18, 2015, 10:41:57 AM »
Hello!
I have started out with MATHCAD, myself, but trying to migrate
to Mathematica. Much more versatile, and FREE on Rapberry PI!
I want to focus on software that I can use for years to come,
and not have to worry alot about the learning curve.( getting old! )
It usually takes me awhile to process a project, and software updates
wait for no one. I know they make advancements and need to sell
software, but I wish they would give my RAM a rest.