Awesome course !

Excelente curso

thank you

Very good

good

the course and the lessons are really interesting and the professor is explaining really well. Especially nice are all the videos demonstrating what have been done so far.

Problem are the assignments:

-all the assignments are about controlling a quadrotor, but a matlab code 95% done is already provided and most of the times the only thing requested is to spend days in find (randomly) the correct values for the controller gains;

-the last assignment is again partly about (randomly) looking for gain values and partly about generating a trajectory as a piecewise 7th order polynomial, where the method for creating such thing is only mentioned in the assignment pdf and with wrong conditions. Even with the correct conditions, with a previous knowledge of numerical methods you can go through it, but otherwise it takes quite some time;

-the grade is not set properly.. you either take 0points or the maximum, meaning that for just passing the assignment you have the same difficulty as getting full marks.. if you arrive (after days of trial and error) to the point of passing the assignment, then you can easily get full grade with small changes.. which makes no sense;

-the explanatory pdf for the assignments or the provided codes some times contain errors, and I don't understand why they are not fixed considering that this course is already the second time that was provided;

-the assignments are fully based on matlab and to actually understand something it is required quite a deep knowledge of how to use it.. I work daily with matlab and had some difficulties in following what it is done. If somebody is new to matlab, it will be quite difficult to do even the easier tasks;

-the evaluation function for the last assignment is extremely slow.. it took me 40minutes to evaluate the results.. and considering the many iterations usually required for (randomly) finding the gains this really doesn't help.

Summarising I am quite happy about this course and glad to have done it, but please fix the many problems in the assignments. I have taken many courses online in different platforms and this was so far the most time consuming one..

Overall good course that would definitely make you spend more time reading and learning on the side. Would recommend it those who have good background in college level math like Linear Algebra and a little bit of Robotics Background from a Math perspective - like working with translations, rotations, transformation matrices of that sort to make the transition easier. (There are basic robotic courses online to help with that, like Peter Corke's course). But overall this course requires some significant effort to explore the material from an external perspective.

Some issues however -

1. Lack of added resources like reading material to support the course and help advanced students go beyond the course themselves.

2. Severe lack of activity from TA(s) on the forums. It's good that students get to interact among themselves and learn on their own, but every single post should be either answered by a TA to clarify doubts or they should acknowledge that another student's explanation was good enough to answer a particular question.

3. The in-video quizzes weren't up-to-the-mark as per me. One question asked "why" and the answer was literally "because that's how that algorithm is".

4. This is a trend in MOOCs and I don't think it can be helped, but perhaps more assignments that help understand the concepts better with examples would help students go beyond. If this course had such optional assignments that would be great for understanding the concepts with a more hands-on approach. But this is probably not the best platform to do so.

Overall would recommend future iterations of this course, especially if the first two points above are improved upon.

Good intro to the subject with clear instruction and responsive support by teaching staff.

Could use many more examples and/or solved problem to help independent learning.

Some notation is confusing, esp. in the later part of the course. Also, the subtle distinctions between a reference trajectory and a "desired" trajectory (in the context of the inner loop for attitude control) are not very clear. There is some art to this which is key to solving the programming assignments that the course could dwell on a lot more.

Pinned conversations in the forums are a big help in tackling the programming assignments.

Overall, the matlab sandboxes, and simulations in the programming assignments, do go a long way in helping us learn about the practical aspects of implementing controllers.

The course could benefit from a top-down (as opposed to bottom-up) overview. For example, it could be stated, early in the controls part *and in context*, that trajectory planning (which will be dealt with later), would yield a reference trajectory for which a controller is being implemented. Instead, it is simply supposed that there is a reference trajectory already available that the controller can try to track. This is just an example.

Some matlab tips on how to add more graphs would help. For example, simulations plot (x,y,z) and velocities but hints on how to visualize rotation angles would also help. The data structures used convert between 2 different "state" structures, one of which does not store angles (presumably because they are not externally specified) but this is what is available at the entry/exit into the code.

The content of the course was good. The lectures were thorough and covered the material well. However, the programming assignments were not (in my opinion) done very well. The instructions were quite vague and didn't give a very good idea of what we were supposed to do. Secondly, the second and third programming assignments had us "tune" certain parameters so that the robot followed the specified path. However, the problem with this was that they gave us no indication of what numbers the parameters should be and given that there were 6 (for the second assignment) and 12 (for the third assignment) parameters to tune to precision, it was an enormous pain and extremely difficult. If they had given us even a range of maybe like 30 values that each parameter should be in, that would have made it so much easier, but there was no indication of any sorts. The only way I got through the assignments was due to guide put together by students and posted on the discussion boards that helped walk through the assignments and told us where to start in terms of the parameters. The content of the course was good, but there is a lot of improvement that could be done with the programming assignments.

The course is definitely has some value. At least it helps to feel the taste of quadrotor control. But there are some cons. 4 weeks is too short, and this entails fragmentation of course materials. A lot of reasonable questions are not answered and even not mentioned: we use Euler's angles, which lead to singularities and ambiguities, there are quaternions, but we'll not use it. Why? - no answer. PD gains tuning is manual. Is there any robust methods to build controls automatically? - no answer. And so on and so forth. And the last... lections are really boring, lector monotonically reads text, nevermind what - matrices, formulas, etc. He reads all of it in completely, with the same manner, without any interactivities with the slides. Actually it is realy demotivates. I guess one of students that made supplementary materials with marker will do much much better.

Anyway, thanks for the course. I believe that highly motivated learner can get something new from it.

Goods:

This course is more of an introduction/overview of the parts of theory for navigation and mapping of drones. Controller part is touched more in depth with a great video on differential flatness. You will easily understand Vijay kumar's paper on "Minimum Snap Trajectory Generation and Control for Quadrotors" after watching this. Topics such as SLAM for mapping and localization, State estimation(Kalman filter) actuators are touched upon very lightly. Nowhere near with intent for implementation.

Bads:

The programming exercises in this course are terrible. In a nutshell in the first 2 weeks you are told to tune some PD gains by just varying values in an input field in a GUI. In next 2 weeks everything is again about manually tuning PD control gains as dynamics equations are straight forward in writeup. All the complexity/dynamics of equations is replaced by PD gains and linear assumptions.

I truly love the course program and what it covers. And aiding student who can't afford the price by grants is relly nice. Then were students alloweed to download MATLAB freely! But teachers should be clear from the begining, what topics one must grasp before getting one's head into it. I don't think calculus and Linear algebra is enough, given some topics that are spoken about in the course. The teacher can explain mean things and in a second, speaks about totally incomprehensibe subject. Last but not least, I personally think the course lacks on additional materials. It would be really nice if there was something like handouts, pdf readings for deeper understanding of the concepts on offline times.

This course was very good and very interesting. The teacher explained things well. The BIG problem with the course is that the level of the lectures no way matched the level of the assignments, especially the last one. It was way too hard compared to the material presented. It was supposed to take 3 hours but it took me more like 50 hours. And from the forum it seems like a lot of people spend 40 or more hours on this one last problem. Was too hard and too much. A lot of prayer and sweat I finally got it with a lot if discussion on the forums. But 40 hours for one problem is crazy. There needed to be a lot more thorough instruction in order to do this problem in a reasonable time.

The course itself was fine. I was disappointed with the assignments. The first two were really easy and required only a couple of equations to be coded in. The last assignment was extremely difficult. Most of the things required to solve the last assignment were not covered in the course and only after reading many posts on the forum could I finish it. The quizzes were annoying too because the options were very close and if you got it wrong, it wouldn't tell you the correct answers.

So, to summarize, my main gripe was with the assignments. They should be more related to the course material and they definitely shouldn't be as hard as the last one.

All in all the material, videos and assignments were very interesting and they made up an exciting course.

However, some of the slides lacked sufficient information on notions or did not make references to supplementary sources. The assignment material (mainly pdfs) sometimes had typos which made solving them a bit confusing and more time consuming without actually being very difficult. Also for both slides and assignments the notations were not always consistent and/or variables disappeared from equations without clear explanations.

I hope in the next offering of this course there will be improvements on these aspects.

Not a beginner course. You need an engineering background to know how to interpret the equations enough to finish the coding assignments in Matlab. Some of the equations presented don't have enough explanation behind them for them to seem in context or to give any idea about how they can be applied.

I have a background in electrical engineering, and I studied control systems in undergrad, so I was able to get by. If you can't manage through this course, don't feel like you aren't smart enough to complete it; rather, you just don't have the proper pre-requisites.

The course provides a good insight into the world of Aerial Robotics and the dynamics involved in controlling the quad-rotors. Were the course fails is it does not explain the basics , there is more focus on trial and error and the questions are not formulated correctly such that they are simple to understand. It could have been better if the Introductory course to the specialization had little mathematical involved or could have been explained in simpler terms or with examples instead of showing the equation in the video.

I think there needs to be more association elaborated between the video lectures and the questions being asked during the lectures. It seems these questions are asked before the lecture itself tends to touch the point of it.

Secondly, it was a bit difficult to associate the assignment write-ups to the lectures. Obviously they were relevant but this should be more clear in text and video.

The course is interesting and entertaining at times, though seems relatively undercooked. Typos in video lectures and assignment writeups are still frequent. The course content is a bit rushed, with some rather difficult aspects left almost unexplained. Definitely not for begginers, as some knowledge of physics, differential equations, calculus, matlab programming is highly recommended!

The course material provided is very good, but there are lack of resources and support for further study or for revision. It says that it is an introductory course but you need to a know lot of things beforehand starting this course and the prerequisites are not stated clearly. If these issues are sorted then its an 5/5 course

Some good material and I good introduction to aerial robotics. But, it doesn't cover all the theory needed to actually write flight control software for a quad copter. If you are really new to robotics you will need to spend at least 40-50 hours a week "discovering" enough of the details to pass the course.

Well I liked the course untile the last assignment. It says you need 3 hours for this assignment but I could finish it after two days (and I am good in programming). The last assignment is not really well designed specially the trajectory part. The rest of the course was good.

Very informative, but the coding elements can be somewhat difficult mainly because there's not many specific examples provided. It is still a very enlightening course. PS You definitely need to at the very least be very familiar with Differential Equations to take this.

The supplementary videos really helped me a lot to understand concepts better. I wish I could see more of these in week 1 and week 2. As a newbie to Robotics and Mechanical concepts, It was difficult for me to follow through the material in week 1 and week 2.

Course needs to be longer, with more quizes and sub projects. The final project is a little harder and some lectures should have been devoted to explaining some more of the mathematics behind it. Also a larger mathematics refresher would have been useful.