 Good day everyone, I am Ruchad Mistry, assistant professor in the mechanical engineering department at WIT Shalapur and today I will be discussing industrial robot configurations. So the learning outcomes for this particular session are, the student will be able to define an industrial robot as per the ISO definition, then explain the Cartesian configuration and its application. So we are looking at only one particular configuration in this particular lecture series and we will be beginning with obviously the definition robot as per ISO standards. Now different textbooks have different definitions of industrial robot, though they do converge in a general direction they have slightly different definitions which is nothing surprising about it. But the best way obviously is to follow the definition as given by ISO and this has been quoted even by the International Federation of Robotics on their website. So we will be following this particular definition for this entire course for industrial robots. So industrial robot as defined by ISO is, it is an automatically controlled reprogrammable multipurpose manipulator programmable in 3 or more axis and which can be either fixed in place or mobile and used for industrial automation applications. So this definition is quite comprehensive and it gives you the scope of what basically an industrial robot is and what we should call as an industrial robot, while it should be reprogrammable that is where we are very clear about it. In multipurpose, so to a certain extent this tells that it is a bit flexible when it comes to applications. It should be able to, the programmable in 3 or more axis, so it just not one directional program, you should be able to program it in 3 or more axis. The platform need not be fixed, so you may have a stationary platform or it may be on a mobile platform. This definition actually has been extended in recent years because you are getting configurations which are now available on a mobile platform especially in a work cell. To sum it up, they make it very clear that it is meant for industrial robot applications. So this is how the definition of industrial robot goes as per ISN also by International Federation of Robotics. Most textbooks now have a variety of classifications and they classify it on the basis of arm geometry which is the most popular and most common configuration followed by degrees of freedom. So arm geometry configuration is typically Cartesian or rectangular because that is how the work envelope looks like, cylindrical, spherical, jointed arms, cara and parallel. So these are the most, this is the arm geometry configuration which is, you will find in almost every textbook on industrial robotics. Another classification is based on degrees of freedom. Now theoretically speaking you can have any number of degrees of freedom but in practice most industrial robots will have 6 degrees of freedom. 4, 5 is also very common. For example, cara robots and parallel robots typically have 4 degrees of freedom. Well it's most jointed arm robots which you find today will have 6 degrees of freedom. So this is the way you can classify. It's also followed by most textbooks. Other ways of classifying obviously is based on applications. So it's very straightforward if they are used for welding, you can call them welding robots. Similarly, you have assembly robots, machine tending robots, palletizing and material handling robots and inspection robots. Another way to classify robots which is quite popular in the past was based on control methods. So you had server and non-server robots. I have just included this because most textbooks tend to be a bit dated and they do control this way of classification. In the modern context I see this to be redundant because all robots are closed loop server robots. So this is the, this classification base is a bit dated but included because most textbooks tend to include it. In server-controlled robots you have continuous path control and point-to-point control. Again let me iterate that nowadays almost every robot will feature these, these control techniques. Like it's very, it's highly unlikely that you will get a robot which doesn't have continuous path controller point-to-point control. That's how the evolution has taken place. So moving forward, robot classification again as per International Federation of Robotics I have included this so that this makes a few things clear and so you can have a direct comparison with the information contained in textbooks. So IFR brochure if you read it clearly states that in general agreement with robot suppliers, robot should be classified only by mechanical structure. So they have made it very clear that they are not following any other classification except for mechanical structure. And by the word mechanical structure they are actually referring to the configuration that we are about to discuss. And as per that they have linear robots which are basically Cartesian or Gantry, SCARA, articulated robots, parallel or delta robots, cylindrical robots and then they have another group which is just others and non-classified. If you notice they have actually dropped the spherical configuration years because this configuration is just, it's no longer used by any top manufacturer. Probably there may be a very old configuration lying around somewhere then you might find it but this is no longer used. So IFR actually now doesn't have this spherical configuration but they do have cylindrical parallel articulated SCARA and the Cartesian configuration. So now we'll begin actually now and discuss the Cartesian configuration. If you look at the figure to the right it's a nice animation which you'll find on Yamaha Motors website. Yamaha also makes precision equipment and robotics other than automobiles. And it shows you a very classic Gantry, sorry Cartesian robot application and you'll notice they are very simple straight linear motions. So the principal axis in Cartesian configuration are linear. They have translation motion only no revolved joints and hence you'll find them labelled as the PPVP stands for obviously prismatic that is prismatic, prismatic, prismatic or linear, linear, linear as the configuration. Remember we come across these labels, remember they are referred to the first three axis. We do not include the end effector axis in this. So first three axis are linear hence it's a Cartesian configuration. One advantage obviously of this configuration that the robot control solution is very simple forward kinematics and even inverse kinematics actually very simple, very easy to program. Before we go to the applications try to think of possible applications for this particular configuration see Cartesian configuration. Now some advantages of Cartesian configuration are being a very simple and robust construction is very accurate delivers very high repeatability. It's simple easy to control movement like I said before forward kinematics inverse kinematics very easy, very simple robot structure so inherently step suitable for large payloads. Lowest cost for a given accuracy yes since the control algorithms are very simple it gives one of the lowest cost for a given accuracy. One more thing is very fast operations are possible and control of algorithms being easy and it's very easy to implement in a controller at a very low cost. This is one of the reasons why these particular configurations are popular. Cost obviously and rigidity was one of the things that go in this in its favor. Obviously every configuration comes with certain limitations and one limitation is in sense that it's not really as you can say versatile I would say as the jointed arm configuration and it's not difficult to read places orientation is nothing comparable to the jointed arm cooperation. Jointed arm configuration can be used if the part has to be located in the most difficult of places. So it's less dexterous when it comes to jointed arm operations and when you're looking at assembly operations especially from the top SCARA is any day better and SCARA is way faster compared to Cartesian configuration. So spot welding and arc welding which requires complex orientation this is not really suited for it and that's why you'll find that in most industrial tasks involved in welding the jointed arm competition is now popular. This particular competition has been replaced by the jointed arm configuration. Applications like I said variety of applications are possible. Remember there is no reason why these configurations cannot be used where other configurations are used but it's just that now those configurations have become popular. However there is a certain you can say a domain of applications where these applications do find preference and one is if you have to pick up an object from the top especially you want to avoid any obstacles in a way. So this is where it comes very handy. I can say gantry like applications so this is where this application finds externally. So you have two animation showing how a very typical Cartesian configuration is applicable in an industrial SCARA for a pick and place task. All are almost involving pick and place operations. The one in the right also demonstrates some sort of an insertion task and assembly task is that's also where this configuration is very very common and you'll notice that it has actually two arms in tandem so that's again very popular. If after generalize you can say applications it typically involves machine tending pick and place tasks transfer of parts as CMMs even alongside CNC machines. Like I said one of the best cases to use Cartesian configuration is when you have to approach a part from top that is gantry configuration where it is very very popular. Now one more thing I'd like to discuss is there's something which I call as state of the art. Now when it comes to industrial robotics what is actually happening in the industry which is state of the art which is most recent which is the best that can offer. Obviously here I'm talking from the context of this particular configuration. So remember the thing with Cartesian configuration is you typically needed some sort of a rack and pinion arrangement obviously because most of the primary actuators were electric motors. So that was the most common way obviously to achieve linear travel. So in the past they were driven by rotary actuators with rack and pinion mechanism and this is still used especially in terms of heavy payload. But Omron very typically in Yavaha they are offering high precision linear motors so this is I would say something which is the state of the art when it comes to linear actuators. And I suggest that you go and look up the websites of Omron in Yavaha and go through the specification of these motors and you'll be surprised with the kind of repeatability and precision these devices offer. So this is really state of the art when it comes to, it requires a lot of reading. International Federation of Robotics the website to go for basic information and data. A very good information source is Robot Park where there's a lot of information regarding robots in general. Again Yavaha Omron is a very informative website when it comes to applications. And one more thing I found very informative was a blog on industrial robots. So you can definitely look these up because some of the older robots you end up finding on blogs rather than websites of manufacturers. So we'll discuss the other configurations in the next video.