Discrete control #3: Designing for the zero-order hold

[@kevinspahr2856]

Brian - just wanted to say that I really appreciate these - I'm a seasoned EE that still loves to learn (and review foundations) and I find these lectures refreshing, succinct, and creative - you are definitely artistic!. I'm finishing the 'analog' (continuous) series and am glad that you are now venturing into the discrete side of things. I know they take a lot of effort (loved the BTS video of how you make these), so on behalf of the 'community', thanks for these videos.

[@Dany_B_Good]

I've learned more in a day watching 3 videos of you than in a complete whole year studying discrete control. Thank you. Greetings from Colombia.

[@hari7591]

Have my electronics and control exam tomorrow, very much enjoying watching these videos on x2 speed to osmosis some knowledge

[@tommcqueary7831]

Thanks for all the good videos. Just wanted to thank you for NOT using background music which ruins so many otherwise great videos I try to watch on KZbin. I studied control theory 45 years ago while getting my BSEE. At that time, all we had was the book and the professor as resources. These videos are a great supplement to these classical resources.

[@satishrengarajan5806]

Absolutely love your explanations! I am designing a controller for motor control and this was exactly what I wanted to see.

[@619pettu]

Waiting for your lectures on STATE SPACE ANALYSIS

[@darkside3ng]

Thank you so much about that!!!!! This video series is the best sequence to understanding this topic over all books or videos that I've seen before :)

[@rubenmorenog7223]

I Just want to complement you for all those amazing and creative videos, you may give class about how to explain all those control topics to my professor. Keep it up!!

[@sahinbozkurt886]

Dear Brian, I want to thank you for these videos. Your lectures help me to understand the concepts of control better. Even though could you please share your advices about digital signal processing and control theory? For example what books you recommend us. Thanks again for your time and these awesome lectures.

[@MrkostasPT18]

ohhh man we need examples of PID designing methods for discrete control!! Please post the 4th part as soon as possible!! If you can, include methods for designing the optimal PID controller for a system without having any specifications!! You have helped me a lot in my research and in problem series!! I appreciate it my Friend!! Again thank you a LOT

[@jitendrasingh-ob8nk]

sir, Your work is unique & different, Thanks to you for making this type of video in which we can related our theoretical knowledge with real practical world. sir it's my request to you that please make a video series on model based controller design like LQR & LQG & kalman filter with real time application such as control speed of DC motor or controller for Inverted Pendulum, please Sir

[@entropyentropy9415]

We need more! :) When is the 4th part coming? Thank you very much sir Brian.

[@mohitks62]

Pls include discete control in your book, its awesome

[@vinitkatariya2585]

We need more videos, Brian. Especially this subject. Please let us know when are the next videos coming?

[@osamamohammed7677]

Thanks Brian! Your videos are the best on the subject. Can the next series be about modern control theory and MIMO systems? I didn't take that subject in university and I'm really interested in learning about it - even though I'm not currently working in this field. Thanks again for putting effort in spreading your knowledge.

[@jimmybakir6283]

Hey Brian I have a question, or if anyone could answer me.. The linear padé aproximation for e^-Ts = (2-Ts)/(2+Ts), and If you solve for the padé aproximation for zoh you get: zoh(s) = 2T/(2+Ts) but Brian Douglas uses zoh(s) = 2/(2+Ts) and its actually a better aproximtaion, Ive tested it, but I cant comprehend where does this come from.. Even if you use the padé function in matlab you get the mathematically correct version (worse aproximation)

[@EmersonPeters]

Hey there! I was wondering if you have a Patreon or something so that you can do these things more often. I have only watched a few videos by you, but I am already really inspired to watch all of these videos and get into this field. I see that these videos take a lot of time and effort to make, and was wondering if I can support this work so that you can do it more often. Thank you so much for what you do!

[@ChuyFlores063]

www.patreon.com/briandouglas

[@samraje17]

Thank you very much Brian Douglas!!!!!!! You rock!

[@ChuyFlores063]

I. NEED. MOARRR.

[@anderselfverson1147]

Really appriciate these videos! Thank you!

[@deept9545]

just awesome

[@MaciekDrozd]

Thank you for this video. I have found here a lot of practical information. How would be the approach if ADC is sampling with different from DAC rate? How to write a model for such a case?

[@chuchoo4047]

I used pade function in MATLAB and tried to get first order pade approximation of exp(-T*s) for 0.2 second sampling time ZOH. what I get was (-s+10)/(s+10) which slightly differs from 10:51. However, the transfer function given 10:51 worked more reliably. can anyone please help me to understand what I did wrong?

[@renatoamorimtorres7915]

Did you figure it out? I also want to know that

[@sergioespinoza2569]

Same here. Anyone know why matlab gives a different pade approximation of the ZOH with a Ts of .2 then what Brian indicated in his video? Thanks,

[@mandippokharel]

it comes from using pade approx in the transfer function of ZOH; (1-exp(-s*T))/sT = 2/0.2*(s+10) =10/s+10

[@edro1128]

@@mandippokharel Wait.. as far as I know the TF of the ZOH is only (1-exp(-s*T))/s where the 1/T came from?

[@mandippokharel]

@@edro1128 you need to consider the effect of sampler too!

[@sathyanarayananramachandra8097]

Salute. Man you are an inspiration

[@AllElectronicsGr]

Great!

[@duanepitt2977]

Brian, can you please cover Mason's rule? Would like to add your videos are well structured and provide a great deal of support.

[@nikkoderic]

Should there also be ZOH at the output of the continuous plant if one uses a digital sensor?

[@mnada72]

Great video as usual... would you mind consider some videos on state space analysis. Thank you.

[@khalidhamed6362]

brain, We need more you are the best ever When is the 4th part coming? Thank you very much sir Brian.

[@BrianBDouglas]

4th part is out now! Working on the 5th at this very moment. Cheers!

[@xdy2817]

Hi Brian. Will you make some videos about nonlinear system, like describing functions and phase plane later?

[@renangeraldes476]

Awesome, thank you for the great job!

[@Sai-rf8xp]

Noob question: if the DAC is a ZOH block then why isn't the Sampler (ADC) also another ZOH?

[@rodmigan89]

Hi Brian!! When are you uploading the next discrete control video? They are amazing!!! thks a lot!!!

[@BrianBDouglas]

Thank you, Rodney! The next video is out now. Cheers!

[@tsunghan_yu]

I'm really confused. Why is ZOH both a discretization and digital-to-analog method?

[@LeopoldoLaborde]

Hi Mr. Douglas, I want to know what software and hardware tools you use to make your videos... your work is very interesting and very good for learn or remember this topics

[@ashutoshpandey2903]

Plz do one video on jury test for discreet stability

[@azamjandali867]

Great content, Thanks!

[@Liliya8719]

hi, i have a question, is there a similar channel about electrical machines? just as fantastic as these videos are!

[@ihabassoun9917]

Have you found it, I am so interested too !

[@sinawodlulisa98]

Thank you Brian. I've got a quick question, why are you not sampling the feedback? Or the input to the discrete controller?

[@yadaKiKhula]

Question about the “motor driver “ - Can this driver be thought of as the combined effect of the “PWM output peripheral of the MCU and the hardware inverter”?

[@henriquetannus10]

yes

[@henriquetannus10]

the PWM peripheral act as a DAC & ZOH

[@orhirshfeld]

As usual its very useful video, few questions I'm not sure what is Hybrid mode and why it's importantto hos you model the planet and controller, is it simulink running mode? Also im not sure exctecly waht you did there with Pade, as far as i know it use to linerazed transfer functions.

[@masoudkhamushi9821]

Hey Brian, i should say you're one of the best at what you do, but i was wondering how do you write all these i mean what kind of device you use, it's been bugging me for so long

[@jamesaddison81]

Hi, I'm wondering if anyone can help.. I have a question(s) about PID control, so I get for a system you create equations of motion, then take the laplace and put in the control diagram, then the same for the PID controller. With that you can do analysis etc.. but firstly, when modelling the response on a computer so graph the system outputs with different PID gains, which equations are you using? Do you just use the original equations of motion and run a time-step simulation or do you use the laplace equations and take it from there? Basically I want to analytically tune a PID controller for a given system (balancing robot kinda project) rather than just do it manually. This may not be the best place to post but hopefully some budding control theory engineers are around and may help :)

[@kwinvdv]

The Laplace transform of a LTI system (so s domain) is mainly useful for designing a feedback controller. When simulating it is more useful to use the differential equations, especially when using nonlinear differential equations, which can't be modeled with transfer functions. Your robot is most likely nonlinear, but if you plan on designing a PID controller based on a linearized model, then you might want to consider calculating the analytical solution by hand and try to optimize that, because that is the strength of LTI systems, their analytical solution is relatively easy to calculate.

[@douglascaires4642]

Hi mate, simulation does not use laplace equations, the computer solver the laplace equation and uses the solution to simulate the results. For tune your PID, you can do it with tunning algorithms. If you want to learn, there are various books on tunning algorithms, and even, self tunning. But, if you just want to tune and be done with it, you can use matlab plug in for tunning PID, you can do it in a few minutes.

[@leadeeeeer]

very good effort, thanks, but why you are making the software so fast, i can't catch it

[@1durch0]

Great video, thx. Do you have any experience with LPV-models in Matlab? It would be nice to see a video from you on this topic.

[@spicy_wizard]

can you tell the difference between pade zoh approximation, and the zero order hold approximation of the model under the comments?? Pade is 1/(1+T*s/2) zero order hold in university is T/(1+T*s/2), in which T is the sampling time many thanks

[@kuraibsaleem9709]

Hello Brian!! Thank you for such great videos. The videos are really awesome. Upload some videos on sampled data systems. Subscribed to your channel right away :)

[@spacespace7008]

Hello Brian and thank you for the extremely helpful videos. I have a question i need to ask: So let's say i have a correct model for my plant and i design a digital PID controller, and that i find the PID gains through a root locus analysis including the ZOH Pade approximation, since everything runs on my microcontroller. I now simulate the system with these gains to get a response. My question is, why do i need to use Tustin's method to descritize the system? Can't i just use the PID gains i found directly for my software, and expect a response similar to the simulated one? Thank you in advance! Greetings from Greece

[@antonete125]

Whrere can I find the techniques to design a controller in the hybrid system?

[@ВладТ-и1у]

Hello. Is there anyone? I have a question. If we have a system, descretisised with a Tustin method, that is control motor with PWM, do we need a ZOH to model it? I mean, I think PWM holds a signal for a while itself. So, what is the thing I don't understand?

[@Sai-rf8xp]

I think the PWM is usually modeled as a simple delay block. I might be wrong

[@alimar1897]

Thanks to points that I don't ever know it

[@MsgrTeves]

You never explained how you got the Pade approximation

[@Googlename699]

Hey brian, Is any 4th video after this one ? Thank you,

[@BrianBDouglas]

Working on it now :)

[@alfajsourav8382]

Hey, can you do examples with actual electrical circuits

[@louis-victorbollinger7630]

Rpz la modélisation système

[@matrixe3]

Jaime tr-s beaucou se que vous avoir dit Mr Bollinger de la France

[@LYJ-d1n]

I love you