 So, far in the course we have looked at many different concepts which are helpful to design mechatronic systems various kinds of mechatronic systems. Now, we will see some kind of a case studies to see how whatever we have learned can be put together to build some innovative kind of a systems ok. So, we will go through some of the research examples from our lab and we will talk about more details how these systems can be really built by using some of the concepts that we have learned. So, let us start with these. So, this is a lab called Suman Mushroom Advanced Microengine Lab that we have developed in department of mechanical engineering at Bombay and this lab must acknowledge the funding by our alumnus Raj Meshwala. At that time about 2007 we developed this lab with funding of about a million dollars from this alumnus and beyond that lot of activities have happened in the lab and lot of new projects have come and you know the facilities got extended and things like that. So, here is we started our activities. So, before I begin like now I will acknowledge these you know all the researchers all our PhD students and M Tech students and RAs who have contributed to this work and of course the funding I mentioned about and there are many other grants that we received later for the research that we are going to see about ok. So, this is like roughly some outline of the talk right now we will use this for 3D micro printing purpose technology of technology called microstimulography I will talk about it similar to our 3D printing in SLL kind of a technology, but I will talk about that and then we will see what are the novelties that we have come up with and how like you know some of these mechatronics concept we have integrated into these systems to make sure they work the way we would like to have them work ok. So, this micro cinematography is simple technology of 3D printing we start with the CAD model in the software and this CAD model as you see here is then software sliced into different slices ok. So, these are software that we have developed in house to create these slices from the CAD model and then further these slices are divided into the lines for the scanning ok. So, each of the slice will be scanned by this line and now if you if the idea is the it will run the laser along this line. So, that the photopolymer resin will get cured only at this part where the laser is scanned and laser needs to be getting switched on and off at these data points ok. So, this is how the requirement for the 3D printing in SLL kind of a way is similar to other kind of a technologies that also exist for 3D printing ok. So, the when you scan you get this kind of a final product out of this system. Now, the question is like when you want to do it at a micron kind of a scale ok the scanning becomes very important and the scanning system needs to have you know much better accuracy at a sub micron kind of a scale ok. So, this accuracy can be provided now that we have gone through this course we know that for a very high precision motion the compliant mechanism stages are going to be useful ok. We have seen that in the CD ROM kind of example ok. So, we developed this concept for this compliant mechanisms later for this scanning purpose, but to scan the laser beam there can be different kind of a methods for scanning ok. So, some of these methods are kind of demonstrated here. So, you can have these mirrors which are kind of tilting and then the lens is focusing the laser beam and then as a mirror tilts the laser beam is going to scan on the on the surface ok. Then you can have the laser beam scan and then the lens is placement is now different than this kind of a method. And then in this case the your tank itself is moving the laser beam is stationary. So, so each of these systems have some advantages disadvantages one can see. For example, this system if you see the scanning goes over the over the sphere and your actually the surface on which the photopolysion happens is flat ok. And this is what happens is like the then laser gets defocused at the other places. And when you want to create micro scale kind of a component you need laser focal length to be very very small ok. So, that the focal spot is small in size. And for such a small kind of a focal spot then this becomes very difficult or infeasible to move this mirror and still keep some reasonable kind of a resolution of the component here ok. Because as the laser gets defocused resolution gets compromised. So, so we propose like a new way of scanning laser beams. We actually propose two ways one of these is this, but this is also better than all the other methods, but it is not great kind of a method of scanning the laser lens here itself in the linear kind of a fashion. Laser is fixed, but the lens is scanned in the linear fashion ok. This we propose first and then like we said that it has some kind of a benefit, but it is not great. Then finally, we propose another method which we could get an Indian patent on is scanning the laser beam along with the mirrors ok. So, mirrors also get scanned in a way that in the linear fashion ok. So, previously we are moving only lens in the linear fashion, but now lens and mirror one they move in the linear fashion and you get a laser beam scan on the surface. Then you can see that the focal plane all the time the laser focal focus remains exactly at the focus ok. Laser remains exactly at the focus entire point on this plane and the same thing can be done with the other direction also ok. So, X and Y direction scanning can happen in this kind of a fashion ok. So, there are many advantages that your spot characteristics remain uniform. So, you can increase the range now whatever like dimension you want to scan you can get that kind of a scanning done. And there is no that is why there is no limit on the range and you have improved resolution happening with this kind of a scanning system ok. So, now to do this scanning in a very precise kind of a fashion then we need stages ok. So, the entire system would look something of this sort ok where your beam is used and split by using this a claustrophic modulator which will which is basically a switch you can imagine that ok. If you if some signal is given electrical signal is given to this switch then it will switch on the light and switch off the light in a matter of like few nanoseconds ok. So, that is what like no the acoustic of acoustic modulator is designed for. Then your beam is getting focused on these fixed mirrors first to kind of we just as they are just a steering mirrors and then you have a actually mirrors which are motion in motion ok. So, these are the mirror that can be used for some adjustment and alignment and those kind of a purpose ok. So, this is how entire system will look like and you will need to move now this mirrors M 1 and M 2 to have the scanning happen ok. Mirror M 1 and lens together will move and then mirror M 2 will move in a perpendicular direction ok to this laser beam with a you know integrated like mirror 1 mirror 2 and lens unit together will move in the in the in this perpendicular direction. So, that is how the XY scan would happen ok. So, these are the two perpendicular direction motion that will be happening for the mirrors ok. So, now to get to this with the submicron kind of a precision that is what I was talking about we need some kind of a compliant mechanism design that we saw ok. So, you remember this concept we talked about you have a you want to move this block by using some kind of a compliant mechanism you start off with simple kind of a scale or cantilever beam which is fixed at one end and you give the deformation the beam moves in the vertical direction, but there are this parasitic errors that there is a tilt here and there is this kind of a parasitic error. Then you add one more beam to that system and then you will find that this will be now better that it has no tilt that is happening to this block, but there is still this kind of a parasitic error exist and then you go for the system where you have this block moving in perfect straight line because of the symmetry ok. So, there are some more integrities about the system you know which will not get into the whole lot of kind of research has happened over these stages to see how their analysis how they their behavior is especially for long deformation or large deformation. So, this idea we implement by using you know developing these compliant mechanism or the flexure stages ok. And these are now further you know manufactured by using the assembly route ok instead of doing like typically people fabricate such mechanism by using some kind of a monolithic block cutting out of that in water jet or some kind of a EDM kind of a machining, but we propose a new way of doing it by assembly route. So, that we get the mechanisms which are also can be built in the third dimension ok and we save some kind of a costly processes. So, this assembly route is not very straightforward. If we start like doing what we have fundamentals that are known in mechanical engineering that you assemble two pieces together you need two pins to locate them with respect to each other. We start doing that and you will find that this mechanism would conventional principles if you do this mechanism will get what ok. Actually if you see this is a picture of the warped mechanism where all the pins are put in all the places and this warping happens. And this warping happens because these beams have a tendency to flex ok or they the tendency to move. So, depending upon like you know small tolerances even if they are very very small you will have this tendency for the for the internal forces to be created when you put these multiple pins. So, we have come up with guidelines which will formal like guidelines which will resolve this issue and give you number of pins to be put at places. So, that you know the mechanism eventually becomes unwarped there is. So, the same mechanism same tolerances on the pins and dimensions are there, but now in this case the mechanism is not warped because of the particular kind of a way of assembling ok. So, we have some publications on this idea ok. So, we use that and like you know we build complete flexure stage and this is like a complete scanning system. So, this is one stage is carried by the other stage. So, this is say x motion stage here and then like you know you have this y motion stage inside this and here there are some kind of a mounts for the mirrors and here there is a mirror mount and the beam is getting kind of steered by this mirrors and it is going finally, on another stage or z stage tank which will be getting moved in up and down direction for the different layers that you want to prepare in the 3D printing ok. So, this is a system that is now built and now this flexural compliant mechanism stages are available. Here you can see that these are some of the mechatronics components here where you your mechanical compliant mechanism stages are integrated with this voice coil actuators and then there are linear encoders to do the job ok. Then we have now this compliant mechanism stages are manufactured by this company called FlexMotion Technologies which is started from here IIT Bombay and this they are now available for many different applications ok. So, now we integrate this mechatronics system for the 3D printing around this. So, we have this data acquisition system called d space ok. So, this is 1104 particular version of this d space company microcontroller and they provide basically this kind of hardware interfaces as a simulink blocks in the MATLAB simulink file ok. So, these are now extra blocks coming in the file. So, what you can do is basically whatever controllers that you built by using simulink or any other kind of a way in MATLAB they can be very easily ported to a hardware system ok. So, that is a ease for very fast prototyping you can do this ok. Although this is a costly kind of a fair, but once this system is available you can do lot of mechatronics system prototype testing very fast ok because you do not need to worry about programming a microcontroller because these are already available as block sets in the simulink block you can just put together those blocks and you start programming ok. You start building the thing and all the things programming will happen automatically for this microcontroller ok. They have developed this kind of a you know the block sets which will which will compile and we build the microcontroller program the way you have maybe you know we have taken hands on training you have written some program in Tiva. Those programs will be built now by a compiler in real time system of a MATLAB ok. So, this is a very handy tool for you know especially those who are mocked up by this microcontroller programming business ok and this is good like you know fast prototyping way of doing things. Then in this board we have now we need to identify what are the channels that we need to use. So, we are using here the digital analog converters to converters for this driving X and Y stages for this driving X and Y stages DAC 1 and DAC 2 which has this amplifier that is used. So, this again so, as we have seen for any high current or high power application you need amplifier to be there to interface with the microcontroller. So, here we are using this concert amplifier for X and Y stage voice coil driving. Now, this is we are using here voice coils as we have seen here instead of motor we have this something called voice coil. It is just a coil and a magnet assembly together and these are non-contact actuators they are guided by this compliant mechanisms and only the magnetic force is applied when the current is passed through this coil non-contact kind of a fashion force no friction is there in the system. Then you have this encoder which are kind of sensors in the system which are reading the data we have seen a lot about encoders how they work and how they can be programmed and things like that ok. So, these are optical encoders, but now they are linear kind of a encoders again they are non-contact and so, entire system has no friction and that is what gives us a way for positioning them with a very fine accuracy ok. And then we need this laser to be switched on and off at certain locations. So, depending upon what you are scanning. So, this is a RF driver for driving this a cost optic modulator. So, this entire thing comes as one unit of cost optic modulator will come along with this driver and you have some kind of a DAC pin which will control the laser intensity ok. It will analog kind of a convert converter between depending upon this analog voltage your laser intensity will be controlled ok. So, this is a system that you need for operating laser on and off depending upon x y position. So, that your scan does scan gets done in a manner that you would like to ok. So, there is one more kind of a DAC that will be used for you know Z stage for giving the Z dimension or like third dimension motion. So, this is how like you integrate then typically you start with the testing of the systems and like know characterizing the system. So, this is how we have characterized the power of the beam that is coming out as input voltage to a cost optic modulator is changed ok. So, this you get a laser spot which is now changing its it can be changing its power depending upon you know what is the voltage that is given as input to. So, if you want to switch off the voltage you give 0 and if you want to switch on the beam at certain point you give some something like 0.6 volts or something like that to kind of get that much intensity for the laser beam ok. Then we test the x y x y stages at different different scanning speeds and here like know this scanning speed is about 0.8 mm per second. We have gone now for the stages which are running at 15 mm per second or 10 mm per second kind of a thing and currently we are building other kind of a resonant kind of a scanning stages which are going at to the speeds as as 300 mm per second. So, that with keeping the same accuracy and you see that position accuracy achieved here is about 200 nanometer ok. So, this is how one can develop like you know the system which can give you the the accuracies which are sub micron level when you want to do like a micro printing or micro scale printing you want to do ok. So, with this kind of accuracies you are able to kind of get your components really fabricated really nicely. So, this is like a entire complete system developed we one of my first PhD students Suhas who was you know working on this in the early days. Now, we have I think the fourth prototype of this micro micro printer coming up in our lab which is having very high speed and high range of component that can be fabricated ok. So, we can see this little video of the entire system here now. So, you can maybe we will show you in the in the next video that we have other video which is coming up here ok. So, this system has this is like a next version of the system you can see here this is a electronics there are interfaced and there is a mechanical scanning system and this mechanical scanning system starts scanning x y stages by using this compliant mechanism and voice coil kind of actuator. And you can see there is a this is a tank here and then there is a z stage on the top of this ok. So, this z stage is what is you know carrying the component up in the z direction ok. So, once the component first layer kind of gets printed like this ok. So, this is a layer getting printed. So, there is a continuous motion in the in the y direction and stepping motion in the x direction that is happening here ok. And this component gets slowly slowly developed here ok. So, this is like a hexagonal kind of a comb kind of a structure ok honeycomb kind of a structure ok. So, this structure is getting developed now and then multiple layers of such structure can be developed. Right now we have kept only for the demonstration purpose the z stage is not seen here, but this layer once it is fabricated it will be pulled off the bottom resin vat and then the next layer of the bottom like the resin will come between the fabricated layer and bottom surface ok. And once that happens then you will have next layer preparation done and next layer can be fabricated in the in the similar kind of a way ok. So, let us move on to this and see some of the components which are fabricated now with the with this printer ok. So, this is now doing the layer by layer it is moving in the it is pulling the component up and then again going down and positioning itself to a level where very thin layer of the liquid is squeezed between the component and bottom of the resin vat ok resin tank here ok. Like that multiple layers it will start fabricating these components and you can get these components fabricated like this. So, this is a honeycomb structure that you saw fabricating fabricated and multiple layers. So, you can get like no thick structures like that ok. So, many structures which are very intricate geometries at a micro scale can be fabricated. So, now we are using this new concept of resonant vibrations to do now you know the similar kind of displacement or scanning at a higher speeds ok. So, let us move on from here to see actually the structures fabricated. These are like different different kinds of structures that are fabricated by these and you can see this scanning electron microscope images of these structures which are showing it like very good dimensional accuracy with respect to the accuracy that we wanted to have ok. So, one can find out fabricate this high aspect ratio micro channels and many different kind of structures that can be fabricated ok. So, I am just displaying these structures to see. So, the one can have see this is a 48 layer kind of a structure. So, 48 times like that such as stepped up and you get this entire structure and inside this you can have whatever geometry of the nozzle that is needed can be realized. Then you can have a boundary scan. So, this is all what you say more kind of refinements or that are done based on the application requirements. The basic mechatronic system remains the same like you have this x, y fracture based scanning stages and there are some kind of a interesting control algorithms that are needed to be used for this kind of a scanning because you do not want to get into vibrations of these compliant mechanisms ok. If they start vibrating unwanted kind of a way then you will get you will start seeing the inaccuracies in your positioning. So, those are all handed at the control level by designing some control strategies which are which are I would say unique to make sure that these vibrations do not depend from the compliant mechanisms stages ok. And still we achieve the job that is needed at a high speeds ok. So, this is that is where like you know lot of these modeling and simulation and fine tuning of the gains those kind of activities would be coming in as we have seen in the course ok. So, this is like constraint surface kind of a fabrication where you are now top surface is constrained instead of. So, what we saw in video was actually this ok the top surface was constrained, but we are not the Z stage was like no upside down it was Z stage was coming up rather than going down in this kind of a way ok. So, this constraint surface is can give you a very high accuracy in the layer because the layer is constrained between two surfaces and though that the surfaces can be maintained at desired accuracy ok. Unlike open like you know without constraint surface you will have open layer liquid layer and liquid layer top surface we do not know whether it will have exactly the same dimension as a thickness that you want to get cured. So, this constraint surface micro siligraphy gives you quite good accuracy in the component produces produced. So, this is a conclusion for this part where like now we see some novel way of scanning laser beam in the linear fashion on the substrate. So, it is like that you can think about your own idea of you know some kind of a way some activity to be done ok. Once that is that idea is there at your in your mind ok then you start putting things together around that idea ok. So, we started off like you know ok we wanted to do some high accuracy kind of a thing then this idea came up of this the new way of scanning laser beam and then we started putting things around that idea ok. This is how like you know you can see this mechanical system can get designed and built in a very nice way and whatever like you know there is some kind of a you will find some things come along way like say for example, in our case we found out how do we assemble this beams very easily that was one of the important kind of aspects. So, that we resolved by like you know formally studying like you know how this assembly is behaving and so, the small experiments very crude experiments help in getting these ideas generated in a faster pace ok. So, we started assembling and you find oh look you have this problem then we study this problem in little bit more mathematical details and then give a solution and then. So, so going back from theory to your practical and practical to the theory like that you know that kind of way of doing things help a lot. So, that is why we started of this course with looking at actually the practical systems the way things work you know if you if you remember with CD ROM and scanners and other stuff. More you can of work with those systems and understand what is going on in there it will help you to design like a new things much better way ok. So, I encourage you to really look at these some of these systems like CD ROM or hard disk drives which are gone you can just open them up and check out ok what are the components that are existing and why they are there like that ok. As we did this analysis you know you you can carry out with many other kind of a devices in the similar kind of a way maybe you are washing machine or like you know any other kind of a tape recorder like you know it seems lot of these devices we may find you know available that you throw away price or they are gone with without any cost people will be happy to give you to explore ok. So, see this is the first kind of a step for developing this product like now we want to get into the product then the further direction is to convert these kind of idea now with a microcontroller like Tiva. See we have used this space as a data acquisition system we cannot use it for actual product ok that is just for the sake of prototyping ok is very costly system and it is it comes with MATLAB MATLAB you do not know you do not have commercial licenses of MATLAB for you cannot ask your customer to do that. So, this space is not a thing for actually find the final product for the final product you need to go back to microcontrollers that we have seen in this course like Tiva where like you start programming this to get your embedded system completely done ok. So, you need to kind of see what all things components I need what all you know these drivers I need all these things can be integrated in the in the in the electronics box with some kind of a microcontroller the choice now we can have based on this course we can have different different choices possibility. There many places you may need this human machine interface with some kind of a touch screen or something to operate the machine ok. So, this kind of a product will be so there are some microcontrollers which will provide you this ok. So, in Raspberry Pi for example, there is some possibility in Tiva also there are some other kind of a versions which are available in Texas instruments other microprocessors which will which will offer this kind of interface ok. And then we can program that to get the complete system as a product ok. So, then like this is this comes to you as a product where there is some touch screen and you have some kind of a pen drive on which you can just put the data of the what is to be printed and it will start printing ok. The way we use our you know 2D printers in home you can have this kind of a way 3D printer as a product can be produced ok. So, this is first part of the thing we will will stop here for now and then we will continue our discussion in the next part about some other kind of a case study system ok. Thank you.