What are Lead Lag Compensators? An Introduction.

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  • Опубліковано 19 жов 2024
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    This videos covers the very basic definition of what a lead/lag compensator is. Every control system engineer should have a basic understanding of lead/lag compensators since along with PID control it is a very popular control technique. This is the first video in a series where I will explain a lead/lag controller, when to use them, and how to design and tune them.
    Errata:
    Don't forget to subscribe! I'm on Twitter @BrianBDouglas!
    If you have any questions on it leave them in the comment section below or on Twitter and I'll try my best to answer them.
    I will be loading a new video each week and welcome suggestions for new topics. Please leave a comment or question below and I will do my best to address it. Thanks for watching!

КОМЕНТАРІ • 213

  • @joannqiongnachen9849
    @joannqiongnachen9849 5 років тому +314

    It's 2019, and I know you're still saving lives.

    • @ooloncolluphid9975
      @ooloncolluphid9975 4 роки тому +2

      he is 😂

    • @isn8103
      @isn8103 4 роки тому +3

      Definitely!

    • @Greg-It
      @Greg-It 4 роки тому +11

      It's 2020, and I know hes still saving lives.

    • @arvinderbali
      @arvinderbali 3 роки тому +14

      And it's 2021

    • @chibi3819
      @chibi3819 3 роки тому +2

      Its 2021 and he's helping me with my electrical engineering finals

  • @divyabharathi-bo5og
    @divyabharathi-bo5og 6 років тому +86

    Every college needs lecturers like you who concentrate on the concepts rather than making us score in our exams with their crude methods! Thank you Brian!

  • @eyasal-rawi8625
    @eyasal-rawi8625 Рік тому +12

    It's 2023 ,and i know you're still saving lives

  • @BrianBDouglas
    @BrianBDouglas  11 років тому +12

    Oh man you're telling me! I was upset how poorly that dark blue recorded but by the time I went to edit the video it was way too late. I'm not using that color again:) Thanks for the comment!

  • @muratadyaman5488
    @muratadyaman5488 9 років тому +103

    i passed the exam fundamental of control systems :) thank you brian douglas

  • @sealedwings6788
    @sealedwings6788 5 років тому +17

    Oh my god. I'm a senior Aerospace Eng. bachelor. This channel is gold. Learning here more than in my univ!

  • @JDanger_
    @JDanger_ 3 роки тому +1

    My professor linked to this video from a lecture as a supplement, and I can see why. Wonderfully helpful good sir!

  • @ismailhossain9495
    @ismailhossain9495 7 років тому +1

    You are a Universal teacher and I am your Universal Students. Excellent and lucid Lectures. Hope our teachers are like you.

  • @mohamedabdelkader8786
    @mohamedabdelkader8786 5 років тому +2

    I'm returning for your videos from time to time to refresh my knowledge and understand things at work. Thanks Brian!

  • @JohnSmith-ed1sr
    @JohnSmith-ed1sr 8 років тому +5

    Thank you Brian! Learned more from you in 11 minutes then 12 weeks in class! Was happy to donate to your book.
    Thanks again!

  • @darvatt
    @darvatt 11 років тому +17

    Thank you so much, Brian. I am currently studying 3rd year Mechanical Engineering, and have lost my interest in Engineering due to poor lectures. However, after seeing your videos, I am more motivated and inspired to study Engineering now, and realise how amazing Engineering is. Hopefully, you can expand your good work, make it 'big' like Khan Academy one day. Wish you all the best!

    • @mechguy118
      @mechguy118 Рік тому +1

      I'm currently 2nd year master's student. You watched it 9 years ago! How's the stuff now as an engineer!?

    • @petrevandermerwe60
      @petrevandermerwe60 11 місяців тому

      @@mechguy118 I'm a working aerospace control engineer and I still revisit his videos. Very relevant, very useful!

  • @Ropsch
    @Ropsch 11 років тому +3

    Brian, I am perfectly happy with the quick math, you have great talent to squeeze a whole lecture into my attention span. As a student I have plenty of examples to practice the math by myself.
    Your videos give me deeper understanding and motivation.
    Thank you a lot!

  • @alirezaghaderi
    @alirezaghaderi 4 роки тому

    Its been almost 6 years since I started to know Control systems. Since then Whenever I need a refresh or forget sth I come back to your video... You are the best sir... Always helpful and always I learn sth new..Thanks and Good Luck

  • @19hashan93
    @19hashan93 11 років тому +6

    Brilliant Lecture. As Usual... Once again, you fixed the big mess I had in my head. Thanks a Million.

  • @aeytam
    @aeytam 3 роки тому +2

    Thank you so much for putting all the efforts into these videos Brian. You are the best.

  • @kvasios
    @kvasios 4 роки тому +1

    As a practicing engineer that was refreshing indeed! Thanks Brian, much appreciated.

  • @guibleme
    @guibleme 8 років тому +115

    My lord in heaven, I've just found the savior. Thank you, Brian.

  • @SP-qp3lq
    @SP-qp3lq Рік тому +1

    It's,2023, And You are still saving lives.

  • @deepikajoshi2701
    @deepikajoshi2701 9 років тому

    Thanx for your videos! Its better to watch your videos than to waste time sleeping during lectures!

  • @LMST72
    @LMST72 11 років тому

    Thanks Brian, these lead/lag videos provided instant clarification on the topic after spending a week scratching my head in class... I'm really grateful!

  • @asamet2007
    @asamet2007 9 років тому +7

    You are phenomenal .. Why don't we have instructor like you ?!

  • @jacobhiller6731
    @jacobhiller6731 9 років тому +9

    My Proff. explained it this way... A Controller (PID, PD, PI) requires an external power source or amplification where a Compensator only emulates a PID, PD, PI controller by lead, lag, or lead-lag compensation WITHOUT the need of an external power source. For example where a PI controller is used to drive steady state error to zero, a lag compensator can only emulate that, driving steady state error very close to zero but not quite there.

  • @aerohk
    @aerohk 11 років тому +43

    Hello! Off topic - Can you talk about state space representation if you are planning on making more videos? I heard that control engineer frequently use the state space approach to design system.

  • @mohibkhan6963
    @mohibkhan6963 11 років тому +2

    Great lectures.Telling us the physical significance of the mathematics and also building our intuition.
    A lot of thanks Brian Douglas. And waiting for more lectures.
    Keep it up.

  • @HassanOmariprofile
    @HassanOmariprofile 5 років тому

    I always go back to your channel when I need to understand/review something in control. Thanks Brian for these truly amazing videos

  • @mnada72
    @mnada72 3 роки тому

    Simply you are amazing, finally after relentless struggle I understood Lead/Lag compensator 😭

  • @michaelcrossey3532
    @michaelcrossey3532 10 років тому +13

    Absolutely fantastic explanation. You are a brilliant human being.

  • @JoeGormanPB
    @JoeGormanPB 7 років тому +5

    This guy is the plug. Seriously thank you so much, I wish I would have found these videos earlier in the semester.

  • @stevenjensjorgensen
    @stevenjensjorgensen 10 років тому +3

    Great explanation! This offers a good introduction and review on what lead/lag compensators are. I tend to agree with your statement and see "controller = compensator." In that, given that the system performs in a particular way, I want give control commands that "compensates" for the undesired performance and turn it into a desired output.

  • @sharikosatia
    @sharikosatia 9 років тому +19

    thanks, learned in 10 minutes more than I did in class.

  • @rhonielguillenredula2507
    @rhonielguillenredula2507 3 роки тому

    This one really helped me recall the fundamentals of control design. Thank you so much!!!

  • @prasadelumalai946
    @prasadelumalai946 3 роки тому

    Its 2021.. its still helping a lot! Thank you 😇

  • @vivekpokharkar3201
    @vivekpokharkar3201 11 років тому

    i did understand the concept when my teacher taught me...but you made it interesting.. Thank you sir!!

  • @badnoodlez
    @badnoodlez Рік тому

    Learned this years ago. Needed a refresher. Very good content 👍

  • @developersclub3810
    @developersclub3810 5 років тому +1

    10:25 these questions, I'm glad you touched upon them..

  • @josepharturopenaquino9812
    @josepharturopenaquino9812 6 років тому

    You are a genius teaching, man
    Thanks for making videos like this

  • @hrithuolickel
    @hrithuolickel 6 років тому

    thank you. finally getting a sense to what I am trying to accomplish with a lag lead comensator. saviour man

  • @ninahooper9608
    @ninahooper9608 7 років тому

    You are literally the best person ever. Thank you.

  • @youssefehab9633
    @youssefehab9633 Рік тому

    Hallo Brian, thank you for your awesome intuitive illustration. I believe the last meant when you introduced the lead lag compensator the locations for the poles and zeros were reversed.

  • @onlyAerik
    @onlyAerik 10 місяців тому +1

    I'm taking notes from Modern Control Engineering by Katsuhiko Ogata, ed. 4
    In chapter 6 section 5, Ogata doesn't really say they're trying to distinguish a controller from a compensator, but does nonetheless describe a compensator in a unique way.
    >In building a control system, we know that proper modification of the plant dynamics may be a simple way to meet the performance specifications.This, however, may not be possible in many practical situations because the plant may be fixed and not modifiable.Then we must adjust parameters other than those in the fixed plant. In this book, we assume that the plant is given and unalterable.
    >In practice, the root-locus plot of a system may indicate that the desired performance cannot be achieved just by the adjustment of gain (or some other adjustable parameter). In fact, in some cases, the system may not be stable for all values of gain (or other adjustable parameter). Then it is necessary to reshape the root loci to meet the performance specifications.
    >The design problems, therefore, become those of improving system performance by insertion of a compensator. Compensation of a control system is reduced to the design of a filter whose characteristics tend to compensate for the undesirable and unalterable characteristics of the plant.
    It's only in chapter 7 around Nyquist techniques that Ogata starts using the phrase
    >... controller (or compensator) ...
    And then by chapter 8, 'controller' alone is used exclusively concerning PD, PI, and PID.
    The overall trend seems to rely on two modes:
    1. Ogata uses 'compensator' when your first and largest reason for modification is stability; you're compensating for inadequacies. Then they use 'controller' when stability is almost a given, and concerns are more with time-based requirements.
    2. There is frequent mention of how PID controllers are modified on-site, implying that a compensator is not. Which I guess further implies that a controller has a human interface, and a compensator does not.

  • @wonderfriend
    @wonderfriend 6 років тому

    Sir, you make understanding so easy. thank you so much.

  • @brendawilliams8062
    @brendawilliams8062 3 роки тому

    Mr Douglas. You have exceptional videos. I ve looked at others. Thx

  • @chiutom4479
    @chiutom4479 8 років тому

    This is very useful video to explain lead/lag compensator.

  • @badarikarthikguddugurike598
    @badarikarthikguddugurike598 7 років тому

    U r simply amazing Giving the concepts in short but clear ..
    Thank you ..

  • @drsandeepvm5622
    @drsandeepvm5622 3 роки тому

    Super simplifying explanation 👌👏 thank you so much for your support to the learners

  • @tkzsfen
    @tkzsfen 11 років тому

    this is something that i will also vote for!!! it's probably the most mentioned thing in my labs and tutorials, but i never got even close to understanding it completely :(

  • @payalpatel4316
    @payalpatel4316 9 років тому

    Amazing lectures. Your way of explaination is the best in this world. Could you please upload more videos so that we can learn more from a wonderful teacher.

  • @UlyssesLizarraga
    @UlyssesLizarraga 11 років тому

    When we have a closed loop system, we are concerned about robustness, which can be determined by something called phase margin and gain margin. The higher the phase margin (measured in degrees) the more tolerant our system is to become unstable due to disturbances; therefore we are interested in modifying the phase to give us a nice "cushion" for uncertainties. Adding a phase compensator might introduce some undesired phenomena such as modifying the original bandwidth. Thanks for the video Brian

  • @leojeon5728
    @leojeon5728 6 років тому

    i found why non ideal PI transfer function has wc ... really helpful video!!!

  • @anantikamehra1694
    @anantikamehra1694 9 років тому +1

    This is seriously awesome. I wish you were my teacher.

  • @achimbuchweisel2736
    @achimbuchweisel2736 2 роки тому

    Very good presentation/explanation. Thank you a lot.

  • @laurasmarrito8479
    @laurasmarrito8479 10 років тому

    Thank you very much for clearly explaining these topics. It was very helpful.

  • @austinfox4130
    @austinfox4130 2 роки тому

    Anecdotally, in my field of servo controlled hydraulic systems compensation is a passive or "dumb" action where a particular variable is acted on by a dedicated system, mechanical or electronic. Whereas a controller performs active analysis on a system and can respond to varying conditions and adjust things on the fly, and have its parameters modified to fit different conditions over time. Often controllers are used to actively adjust setpoints in compensators. For example, a pressure compensator may control the flowrate of a pump by constantly adjusting itself to maintain constant pressure at different pilot pressures. That pressure compensator is itself controlled by a proportional servo valve which can actively adjust that pressure compensation gain if desired.

  • @kirtikansal6946
    @kirtikansal6946 6 років тому

    thnx for the wonderful vedio @brain Douglas and all the guys who comment here also remove many confusions..thnx to them tooo

  • @barisukauebari8563
    @barisukauebari8563 4 роки тому

    I'm interested in MATLAB Control Tutorial. You have great videos. Thanks so much.

  • @francesconigri745
    @francesconigri745 2 місяці тому

    it's 2024 and I am sure you are still saving many lives

  • @AJ-et3vf
    @AJ-et3vf 2 роки тому

    Awesome video lectures sir! You're an immense help for us to grasp the concepts and theory of control. Thank you very much

  • @thomasyen5706
    @thomasyen5706 6 років тому

    Fantastic Lectures! It really helps a lot!

  • @lubwee
    @lubwee 10 років тому

    wish my control system lecturer was like you.

  • @anishayush9383
    @anishayush9383 6 років тому

    Controller is for time domain response analysis and compensator is for frequency domain analysis of a system.

  • @sallybryan3754
    @sallybryan3754 6 років тому

    The best video i have ever watched

  • @ka-ew8ui
    @ka-ew8ui 8 років тому +2

    from the comments below i see that you deliver a great explanation by the examples of the real life you give, but i hope that you make more videos with mathamatical examples also because i cant really have the full picture sometimes of what you are saying , it would be awesome if you do this, i know its boring for you because you do it faster using matlab but it would be really helpful for us in our studies if you could do that.
    thank you in advance

  • @johnoh537
    @johnoh537 7 років тому

    Thank you so much for the video, Brian.

  • @smithjohn1164
    @smithjohn1164 5 років тому

    Brian,your videos make me understand a lot of control system. Can you teach Mason's gain from your aspect? I will very appreciate.

  • @omarsh77
    @omarsh77 5 років тому

    Thank you. great simplification with good knowledge.

  • @nichoyeah
    @nichoyeah 4 роки тому

    THANK YOU FOR ALL YOUR VIDEOS

  • @AlexStevens3
    @AlexStevens3 10 років тому

    These videos have been extremely helpful, thank you!

  • @ashwinimohan6467
    @ashwinimohan6467 7 років тому

    active ckt is required for designing controllers pi, pd,pid . and a passive ckt for compensators lag,lead,leadlag. i guess that's the difference.. awesome video btw

  • @TheJeenesan
    @TheJeenesan 10 років тому

    Thank you very much for sharing your knowledge. I saw all your control system videos and all were very useful. Maybe state space representation lectures would be great.Thanks again and all the best!

  • @TheDi430
    @TheDi430 5 років тому

    Hi Brian! First of all, I'd like to show you my gratitude for your channel content, it is really helping me out with my college assignments. About this topic, I have a question. In what situation a lead compensator can reduce the stability robustness of the control system?

  • @aleksanderbanach2755
    @aleksanderbanach2755 Рік тому

    zajebisty jesteś gościu nie zmieniaj się

  • @slow_white
    @slow_white 7 років тому

    I had the same confusion about compensator and controller, thanks for mentioning it. btw, like your voice too

  • @maythammahdi5238
    @maythammahdi5238 2 роки тому

    From 2022 you're helping me

  • @dandymcgee
    @dandymcgee 2 роки тому

    As someone with zero experience in this domain, my default understanding would be:
    A controller is anything that controls something.. i.e. it has an output that is used as something else's input (e.g. how much power to deliver to a motor, or switch an LED on / off, or send a network packet, etc.). You can have hardware controllers and software controllers, and not all controllers are compensators.
    A compensator is a controller that also has a feedback input from which it reads a signal that it uses to help it make its decision about how to control. All compensators are controllers.

  • @abdulsamirkhan3813
    @abdulsamirkhan3813 7 років тому +1

    Sir.! Your videos are amazing and helps alot in clear understandings of topics.
    I have a question regarding definitions of controller and compensator.. Can we say that " Controller is used to improve time response characteristics and compensator to improve frequency response characteristics" .?

  • @suman3316
    @suman3316 9 років тому +4

    Hello sir your videos are awesome sir.....
    Please make videos on state space analysis also

  • @LUISBUENOBLANCO
    @LUISBUENOBLANCO 11 місяців тому

    This guy is a genius

  • @Brandon_Behnen
    @Brandon_Behnen 11 років тому +9

    To answer your question posted at 2:20
    I would look at the two terms based upon intended definition:
    Controller - send instruction before execution, then correct execution error
    Compensator - send instruction after execution in order to correct execution error

  • @nickdebruyckere12
    @nickdebruyckere12 2 роки тому

    you are so amazing at this

  • @laallyal
    @laallyal 11 років тому

    Brian, this is truly great stuff! Thank you very much! Improvement suggestion: at 4.35 you use a very dark blue. It strained my eyes when i tried to read it against the black board. However the light blue worked perfectly :) Cheers again!

  • @tarunasudhakar6684
    @tarunasudhakar6684 6 років тому

    You're just brilliant! I LOVE THESE SO MUCH THANK YOU

  • @luisgerardorodriguez7964
    @luisgerardorodriguez7964 2 роки тому

    For what I know, a compensator has the function of compensating the effects of increasing the proportional gain. Ideally, the proportional gain should be big, so that the output can follow the input, however, increasing the proportional gain too much can make the system unstable, and that is the moment where the compensator has relevance.

  • @alawiiabdullah7437
    @alawiiabdullah7437 6 років тому

    I have got full answers for all of the points that stack in my mind so thanks a lot ^_^

  • @cecilialogatto6209
    @cecilialogatto6209 7 років тому

    I think that a compensator is a type of controller which compensates the specifications with one or more couple of poles and zeros. Instead the controller can be just proportional, or integral and so on

  • @kinderb_mp3
    @kinderb_mp3 9 років тому +2

    This videos are amazin man. Thanks a lot! Greetings from Peru :)

  • @jp4400
    @jp4400 4 роки тому

    Great video, great explanation. One more subscribed at the channel! Thanks sir !

  • @gaddamabhishek4771
    @gaddamabhishek4771 6 років тому

    thank you for your example demonstration, sir.... im very helpfull..

  • @Cliu960129
    @Cliu960129 6 років тому

    Hey Brain thanks for the video it's really helpful. I think my prof said something like compensators are 'dynamic' controllers

  • @jasonchen3659
    @jasonchen3659 7 років тому

    Good job, this video really explains a lot.

  • @bablubablu490
    @bablubablu490 9 років тому

    Seriously uh nailed it. Thank You Sir

  • @nijatibrahimov7451
    @nijatibrahimov7451 9 років тому

    You are amazing, Brain! Thanks for great tutorials :)

  • @chrisschindlbeck
    @chrisschindlbeck 8 років тому +12

    Compensator = feedforward
    Controller = feedback

  • @vitorpereira8458
    @vitorpereira8458 5 років тому

    You are great, really make a difference. Thanks!

  • @R0kmyS0X
    @R0kmyS0X 8 років тому +8

    Controller is what converts the error into feedback. Compensator is something that changes the system to make up for design shortcomings.
    thats my guess

  • @AdityaMishra-pp1gw
    @AdityaMishra-pp1gw 4 роки тому

    You said that the pole and zero would mathematically cancel each other and it's a silly example but should we cancel them keeping in mind the state space approach and the Asymptotic stability?

  • @sobhnathpal934
    @sobhnathpal934 4 роки тому

    Thank you ,you're doing a great job

  • @srinivaspilla6044
    @srinivaspilla6044 7 років тому

    Effect of adding poles and zeros to system? eg: root locus,stability etc.
    Please,Can you make a video on this topic?

  • @mikel4698
    @mikel4698 10 років тому

    Thanks! I wish you were my controls prof :)

  • @toughcookie2429
    @toughcookie2429 8 місяців тому

    I have a question, is the gain plot graph of combined lead and lag compensator is correct?? I think there should be a gain (positive or negative) for lead frequencies also.

  • @facundoagustindemarco7106
    @facundoagustindemarco7106 3 роки тому

    I LOVE YOU BRIANNNNN