Articles by tag: innovate

Articles by tag: innovate

    Intake System Competition

    Intake System Competition By Evan and Austin

    Task: Compare build designs for the cryptobox intake system

    The block scoring system is going to be an integral part of the competition this year, and it will have to built sturdy. It’ll have to be reliable for us to have any shot of winning any matches. So we got to brainstorming. We spent a while at the whiteboard, drawing up various mechanisms and ways to pick up blocks. One idea was the idea of a block delivering system similar to those modern vending machines that have two degree of freedom movement. We began to design the contraption so that a conveyor belt could be placed on an up and down linear slide to position the blocks just right to make the different symbols. Another person came up with the idea to use our tank treads from Geb, our competition robot from two years ago, to push the blocks up a ramp and deposit them into the cryptoboxes. Neither of us could convince the other about what was to be done, so we both split off to work on our own models. Next week we will keep working on this build off of the century.

    Further Design of the Intake

    Further Design of the Intake By Evan and Austin

    Task: Design the grabbing systems further

    The sun came out and it was back to the field. We got started right away, both of us building our designs. Since the cryptoboxes were wider than the 18 inch sizing cube, we started by designing a fold out for the conveyor belt. This was entirely proof of concept, purely to see if it was at all aplicable in the game this year. We spent an hour or two gathering parts and put together an extending conveyor belt. This device would swing down, like the arrow suggests, allowing for more space to move the blocks back in forth, giving us accuracy in rune completion. This will be later attached to linear slides, allowing for an up and down motion.

    Intake Systems

    Intake Systems By Austin

    Task: Work on designs for the intake system

    Over the past couple of days we’ve experimented with a horizontally mounted track system that we had hoped would serve to move blocks through the entire length of the robot and into the crypto box. Immediately we noticed a few issues, the primary one being that the tread was static in terms of mounting and therefore wasn’t accepting of blocks when feed at an odd angle. To correct our feeding issue, we widened the gap between the tracks and added rubber bands in hopes of maintaining traction and adding to on demand orientation ability.

    Initial tests of our second prototype went fairly well, however the design suffered from some severe drawbacks; the first was its weight and size which would limit robot mobility and take up much needed space for other components, the second issue was that keeping the treads tensioned perfectly for long periods of time was nearly impossible and they would often sag leading to loss of grip, and finally the system was still fairly unpredictable especially during intake (blocks were flung occasionally). These finding lead me to believe we may scrap the idea in consideration of time.

    Aside from our track intake we’ve also been working on a gripper and slide system that shows promise.

    Narrowing Down the Designs

    Narrowing Down the Designs By Evan and Austin

    Task: Redesign our grabber systems

    In an attempt to get a working lift system before the coaches meeting we will be presenting at, a linear slide has been attached to the robot, along with a pair of grabbing arms. They work surprisingly well and aren’t as complicated as my idea. Plus the importance of speed has really taken hold on me this year. We need to be as fast as possible but my contraption is slow compared to the grabber arm. I think we'll be scrapping the idea for this grabber arm bandwagon everyone seems to be hopping on. While the grabber arm allows for quick pick ups and easy placement, our idea was only bulky and unnecessary because of our use of mecanum wheels which eliminate any need for a system to go side to side. Since the grabber was rudimentary, we’ll be making improvements and new iterations. We toyed with some materials earlier on in the season, and we’ll probably be implementing that into it.

    Slide Designs

    Slide Designs By Austin

    Task: Figure out slide mechanism

    After determining that the treaded channel was much too buggy to perfect with the time we had, we shifted attention to other scoring systems like grabbers, however before finding the right grabber we decided we needed to get the track for it completed first. We’ve had experience in the past with all sorts of rails from Tetrix kits that convert their standard channels into lifts, to the newer REV sliding rail kits which we also toyed around with in initial prototyping shenanigans.

    One of our key concerns was also wear and tear, in that we have had systems slowly breakdown in the past, such as our mountain climber and catapult, since they had plastic components that broke over time, we knew that long periods of use over multiple competitions would deteriorate the plastic components of either rail sets, and other rails that used full metal parts would simply be bulky and rough to fit in snugly with our robot. After a bit more research we settled on standard steel drawer slides from home depot, mainly because they were streamline and all around sturdy. The slides also provided us with easy mounting points for our future claw and attachments.

    We understood that whatever option we picked for slides would have to be easily repairable or replaceable during competition, should something go wrong. Since the drawer slide were easy to come by and needed little modification we could easily make duplicates to act as stand by and demonstration parts during competition.

    These positives came to form more than enough of a reason to continue prototyping our grabber that would eventually be attached once completed to the lift, which was now mounted to the robot and used a system of spools and pullies to extended above the minimum height for scoring in the top row.

    Building Competition 2017

    Building Competition 2017 By Evan and Austin

    Task: Find the best robot design

    The games have begun and it’s time to build. So that’s what Austin and I did. A war had been declared. Legions of the indentured collided on the battlefield. Millions were slaughtered during this new age armageddon. Austin had his army. I had mine. Two different ideas to do the same task: lift glyphs into their correct positions. A simple job but one that caused a rift in Iron Reign, an incurable rift between the forces of light and darkness.

    But then I decided to stop because his design had more speed than mine and speed is more necessary this year. My idea had been a lift that could move the glyphs back and forth but I realized that it would be a little too slow for the competition. Or, another solution would have had a side to side conveyor belt that moved glyphs back and forth to arrange them in the correct order, and then push them into the slots. This movement would have been separate from the four mecanum wheels that we are using in the chasis. His idea was simpler than mine, a conveyor belt that ran through the middle of the robot to bring the glyphs to the keybox, where they could be slotted in with the side to side movement provided by the mecanum wheels. So, like an outnumbered Supreme Court judge, I decided to join the winner so I could have a say in the early design. Once he got a prototype ofhis contraption working, it was able to pick up blocks effectively but it still needs improvement. It has issues with blocks at an angle, and it has trouble slotting the blocks into the keybox, but it's a nice step toward a working block system. We are currently planning to use the mecanum wheel base we used last year but this could change anytime. We left practice with a direction and that's better than nothing.

    Testing Materials

    Testing Materials By Austin, Evan, and and Tycho

    Task: Test Materials for V2 Gripper

    Though our current gripper is working sufficiently, there are some issues we would like to improve in our second version. The mounting system is unstable and easily comes out of alignment because the rev rail keeps bending. Another issue we've encountered is the cervo pulling the grippers so that they begin to cave inwards, releasing any blocks being held at the bottom. By far the biggest problem is our intake. Our drivers have to align the robot with the block so precisely to be able to stack it that it eats a majority of our game time. However, there are some advantages, such as light weight and adjustability, to this gripper that we would like to carry over into the second version.

      We tested out a few different materials:
    • Silicone Baking Mats - The mats were a very neutral option because they didn't have any huge advantages or disadvantages (other than not adhering well). These could have been used, however, there were other better options.
    • Shelf Liner - It was far too slippery. Also, when thinking about actually making the grippers, there was no good way to put it on the grippers. Using this materials would have been too much work with little gain.
    • Baking Pan Lining (picked) - It was made out of durable rubber but was still very malleable which is a big advantage. We need the grippers to compress and 'grip' the block without causing any damage.
    • Rubber Bands on Wheels - This material was closest to our original version and, unexpectedly, carried over one of the problems. It still requires very specific orientations to pick up blocks, which would defeat the purpose of this entire task.

    The purpose of this is as a part of our future grabber design, which will need to be relatively light, as our string is currently breaking under stress due to weight. The material must also have good direct shear and direct strength, as the grabber will have rotating arms that move in and out to grasp blocks. As well, we're replacing the tetrix parts with REV, as they're smaller and a little lighter, with the additional bonus of more mounting points.

    Designing the Grabber Further

    Designing the Grabber Further By Evan

    Task: Design the grabber design and make future plans

    The grabber has been evolving. A column made of a turkey baster and a wooden dowel attached to servo has come into fruition. The first drawings and designs are coming along, and some 3D printed parts have been thought up to allow the square dowel to become a hexagon. An adapter of sorts. The grabber and lift have been outfitted with a back board to stop blocks from getting caught underneath the backing bar. The back board is just some 1/16th inch wood cut to fit. The new turkey baster columns are in the first stages, so more info on them will come as more is discovered and progress has been made. The sketches will explain these designs better.

    Designing the Grabber

    Designing the Grabber By Austin

    Task: Work on the grabbers more

    With our single degree of freedom lift fastened to the robot we focused on the appendage that would grip to within an inch of its life any glyph we fed it. We initially toyed with simple tetrix channels to form a make shift rail that would hold axels for pivoting points, however we found tetrix to be a bit too cumbersome and decided to use rev rail instead. Using two tetrix U-brackets we built a makeshift grabber that used rubber bands and a servo to secure blocks without letting them slip through its grasp. To add extra grip to the long L-beams that formed the pincers of the claw, we added even more rubber bands, and moved on to testing.

    Initial tests were very positive, the high strength servo coupled with a few rubber bands maintained enough of a grip on one or two blocks with ease, and because the entire system was mounted to a rev rail we could easily slide and size the pincers to the right distance. Feeling confident in our work we attached the grabber to the lift and attempted drive practice, which ended relatively quickly due to a surprising number of jams between the lift and glyphs.

    The key issue we now faced was that as the lift returned to its home state blocks were getting stuck beneath the retracting claw causing jams. To fix this relatively simple problem we added a back plate to the claw that kept blocks from slipping to far into the robot, this was easily fashioned out of a bit of thin wood board we had lying around from the decks of other robots. The overall performance of our glyph wrangling device was astounding, so long as whoever was operating the robot was a well-trained driver.

    V2 Hexifier and Parts

    V2 Hexifier and Parts By Tycho and Abhi

    Task: Creating the Parts for V2

    Today we continued our work on the second grippers. We talked about this in another post, but the gist is that we iterated through various materials to find something that would securely grip the block, without damaging it. At the beginning, that got rid of most of our options, but we tested various sprays, materials, and pressures to find the right material. The baking pan liner was the best, as it had some give without damaging the block, but had enough friction that slippage was a minor issue. So, we needed the baking pan liner to adhere to the large square dowel we chose to be the base for our grippers. In order to do this, we had to design and print a hexifier, as seen below, which makes the dowel's square shape into a hexagon. We also designed and printed square pieces to go on the top and bottom of the gripper to keep it in place.

    Reflections

    The new grippers are probably going to be much heavier than our previous ones. Not only because of the difference in material, but in sheer size. We may not be able to retain the lightness in V2 that we had hoped to.
    We used PTC Creo for all of these parts. Abhi has some video tutorials on using Creo that can be found here and here. Soon we will start assembling our V2 grippers.

    Machine Vision Goals – Part 1

    Machine Vision Goals – Part 1 By Tycho

    We’ve been using machine vision for a couple of years now and have a plan to use it in Relic Rescue for a number of things. I mostly haven’t gotten to it because college application deadlines have a higher priority for me this year. But since we already have experience with color blob tracking in OpenCV and Vuforia tracking, I hope this won’t be too difficult. We have 5 different things we want to try:

    VuMark decode – this is obvious since it gives us a chance to regularly get the glyph crypto bonus. From looking at the code, it seems to be a single line different from the Vuforia tracking code we’ve already got. It’s probably a good idea to signal the completed decode by flashing our lights or something like that. That will make it more obvious to judges and competitors.

    Jewel Identification – most teams seem to be using the REV color sensor on the arm their jewel displacement arm. We’ll probably start out doing that too, but I’d also like to use machine vision to identify the correct jewel. Just because we can. Just looking at the arrangement, we should be able to get both the jewels and the Vuforia target in the same frame at the beginning of autonomous.

    Alignment – it is not legal to extend a part of the robot outside of the 18” dimensions during match setup. So we can’t put the jewel arm out to make sure it is between the jewels. But there is nothing preventing us from using the camera to assist with alignment. We can even draw on the screen where the jewels should appear, like inside the orange box below. This will also help with Jewel ID – we won’t have to hunt for the relevant pixels – we can just compare the average hue of the two regions around the wiffle balls.

    Autonomous Deposition – this is the most ambitious use for machine vision. The dividers on the crypto boxes should make pretty clear color blob regions. If we can find the center points between these regions, we should be able to code and automatically centering glyph depositing behavior.

    Autonomous glyph collection – ok this is actually harder. Teams seem to spend most of their time retrieving glyphs. Most of that time seems to be spent getting the robot and the glyphs square with each other. Our drivers have a lot of trouble with this even though we have a very maneuverable mecanum drive. What if we could create a behavior that would automatically align the robot to a target glyph on approach? With our PID routines we should be able to do this pretty efficiently. The trouble is we need to figure out the glyph orientation by analyzing frames on approach. And it probably means shape analysis – something we’ve never done before. If we get to this, it won’t be until pretty late in the season. Maybe we’ll come up with a better mechanical approach to aligning glyphs with our bot and this won’t be needed.

    Tools for Experimenting

    Machine vision folks tend to think about image analysis as a pipeline that strings together different image processing algorithms in order to understand something about the source image or video feed. These algorithms are often things like convolution filters that isolate different parts of the image. You have to decide which stages to put into a pipeline depending on what that pipeline is meant to detect or decide. To make it easier to experiment, it’s good to use tools that let you create these pipelines and play around with them before you try to hard-code it into your robot.

    I've been using a tool called ImagePlay. http://imageplay.io/ It's open source and based on OpenCV. I used it to create a pipeline that has some potential to help navigation in this year's challenge. Since ImagePlay is open source, once you have a pipeline, you can figure out the calls to it makes to opencv to construct the stages. It's based on the C++ implementation of OpenCV so we’ll have to translate that to java for Android. It has a very nice pipeline editor that supports branching. The downside is that this tool is buggy and doesn't have anywhere near the number of filters and algorithms that RoboRealm supports.

    RoboRealm is what we wanted to use. We’ve been pretty closely connected with the Dallas Personal Robotics Group (DPRG) for years and Carl Ott is a member who has taught a couple of sessions on using RoboRealm to solve the club’s expert line following course. Based on his recommendation we contacted the RoboRealm folks and they gave use a 5 user commercial license. I think that’s valued at $2,500. They seemed happy to support FTC teams.

    RoboRealm is much easier to experiment with and they have great documentation so now have an improved pipeline. It's going to take more work to figure out how to implement that pipeline in OpenCV because it’s not always clear what a particular stage in RoboRealm does at a low level. But this improved pipeline isn’t all that different from the ImagePlay version.

    Candidate Pipeline

    So here is a picture of a red cryptobox sitting against a wall with a bunch of junk in the background. This image ended up upside down, but that doesn’t matter for just experimenting. I wanted a challenging image, because I want to know early if we need to have a clean background for the cryptoboxes. If so, we might need to ask the FTA if we can put an opaque background behind the cryptoboxes:

    Stage 1 – Color Filter – this selects only the reddest pixels

    Stage 2 – GreyScale – Don’t need the color information anymore, this reduces the data size

    Stage 3 – Flood Fill – This simplifies a region by flooding it with the average color of nearby pixels. This is the same thing when you use the posterize effect in photoshop. This also tends to remove some of the background noise.

    Stage 4 – Auto Threshold – Turns the image into a B/W image with no grey values based on a thresholding algorithm that only the RoboRealm folks know.

    Stage 5 – Blob Size – A blob is a set of connected pixels with a similar value. Here we are limiting the output to the 4 largest blobs, because normally there are 4 dividers visible. In this case there is an error. The small blob on the far right is classified as a divider even though it is just some other red thing in the background, because the leftmost column was mostly cut out of the frame and wasn’t lit very well. It ended up being erased by this pipeline.

    Stages 6 & 7 – Moment Statistics – Moments are calculations that can help to classify parts of images. We’ve used Hu Moments since our first work with machine vision on our robot named Argos. They can calculate the center of a blob (center of gravity), its eccentricity, and its area. Here the center of gravity is the little red square at the center of each blob. Now we can calculate the midpoint between each blob to find the center of a column and use that as a navigation target if we can do all this in real-time. We may have to reduce image resolution to speed things up.

    Gripper Construction

    Gripper Construction By Tycho

    Task: Making the Gripper

    Standard parts were used to create the backbone. Then, we bent some tetrix parts to connect the backbone to the servos. We used continuous rotation cervos to solve the issue mentioned earlier. This was a fairly easy build but we still have a ways to go before V2 is completed.

    This gripper will be far superior to our prior designs in that it will be lighter, as we are substituting wood and rubber for metal parts, which will solve our string breakage issue. As well, we will be able to grasp objects more securely, due to the rubber's larger coefficient of friction and that the gripper arms themselves have more surface area than our original design. Finally, our gripper will be more dependable due to slightly better wire organization than before.

    This helps our strategy in that it will be far easier to pick up individual blocks, and helps us achieve our goal of grabbing multiple blocks at once. The wider gripper arms will make it so that we can stack blocks on top of each other before bringing them to the CryptoBox, which makes our robot 1.5x as fast in operating time.

    Gripper Part 2

    Gripper Part 2 By Evan

    Update:

    The task today was simple. We replicated the prior work with the first gripper, as stated in the prior post, so we can begin connecting them. The biggest problem was finding all the parts to make it. We are hoping we can connect and mount them in the next couple days so it will be ready for the qualifier in Oklahoma. The improvement over last post was the addition of the rubber gripping material, as found in our "Material Test" post.

    Intake Grippers Pt2

    Intake Grippers Pt2 By Evan

    Task: Attach the new intake grippers

    The basters are here and in full swing. We spent a late night putting together the two intake columns. They were attached to a backing by previously, allowing to finish it by attaching the final servo and tieing it to the two columns. Since the new intake needed new code, we whipped up some code to allow us to have control. Upon doing this he realized we needed two controllers, one for movement and controlling the lift, and a second purely to work the two columns as they spun. This allowed the operator to operate the whole robot just a little easier. The new columns are set on a majority REV base, allowing for more choices in design that normal tetrix doesn’t provide. The new grabber has already been placed on the robot and seems to be working smoothly, only time will tell if it is a long term solution.

    Grabber Arms v3

    Grabber Arms v3 By Abhi and Karina

    Task:Develop a More Efficient System

    At the Oklahoma qualifier, we saw numerous teams with similar systems to that of ours. However, since we had the mobilized gripper arms to stack with auto alignment, we were able to collect glyphs easier. In spite of that, after observing other teams in action, we realized our current gripper method had the issue of not being ready by the time we got back to the cryptobox. This is because we had to turn around everytime we needed to pick up glyphs and we also needed to pick up glyphs. This leads to longer time to fill the cryptobox, something that is not good if we plan on recovering the relic later in the season. As a result, we decided to upgrade our arms to a new level: a chain based intake system.

    The idea behind this system is that the grabber arms would be on a mobilized chain system, kind of like a conveyor belt. One of the reasons this is much faster than our old system is that we don't need to turn our robot around as we approach the cryptobox. We can drive forward, pick up glyphs, and as we drive backwards, we can use a toggled button on our gamepad to move the grabber arms to the back of the robot upright. As a result, by the time we get back to the cryptobox, we have the glyphs ready to place.

    Another benefit of this new system is that we don't need to stack glyphs. When we drive forward to pick up glyphs, we can tilt the grabber arms forward so that even if the pre stacked glyphs look far apart, they can still be in-took with the tilted system. Also, this system can be used for intaking the relic in the future. If the chain system is placed on an elevated level on our robot, the grabber arms will be taller than the field walls. Because of this, if we pick up the relic when it is on the ground, we can place it easily.

    This picture represents our current progress. We hope to complete this system soon so we can test it on the robot.

    Gripper v4, Octopuckers

    Gripper v4, Octopuckers By Tycho and Abhi

    Task: Design a new piece for intake

    Version 2 of our gripper arms worked much better than our original. Due to their silicone material and trianglular shape, we definitely had more control over the glyphs than our one degree of freedom grabber arms. However, we still had issues we needed to address. When glyphs were taken in, since the silicone surface did not have much mobility and compressibility, glyphs would often fall. Due to slight changes in glyph size, the bigger glyph would determine the space between the grabbers, meaning the other glyph would be mobile despite us wanting its control. This is when we develoepd the first version of our new rotators.

    The first edition of our rotatory mechanism allowed us to play with ninjaflex printing and flexibility. They were 15mm extrusions designed to stack on one another on a REV rail or similar rigid structure. Since Ninjaflex can bend, we got more grip on the glyphs. It was definetely a well designed model but had many issues. First, each fin of the fan was very thick. Though it was able to grip glyphs well alone, the system was not able to grip much better when stacked together. We decided we needed more surface area contact with glyphs during intake.

    This led us to create a new model with thinner fins and thin tabs at the end. The thin flaps allowed more grip area with the glyphs allowing us to work better. Though good in theory, when we went to print out the part, we discovered our 3-D printer didn't allow printing vertically of surfaces less than 1 mm. Since this idea didn't work, we started thinking of the idea of suction cups. This led us to our current design.

    The design worked very well. We decided to name them Octopuckers since they had suction cup shape and there were 8 fins to a pucker. The surfaces of the octopuckers which would contact the glyphs were large and had a large area. Since this was heavier than the bridge connecting them to the center, the branches bent easily allowing for a grippy surface which was also flexible. After testing it on a small scale, it seemed to work well so we will continue development and implement it on our next edition of the grabber arms.

    Flipper Prototype

    Flipper Prototype By Evan

    Task: Build an alternate glyph-placing mechanism

    The world advances on innovation. We strive to make the most efficient devices and aparati to complete jobs for us. There’s a hundred different ways to work a task, but only one will be the best at functioning in the areas of efficiency and timeliness. Just as America runs on Dunkin, advancement runs on efficiency. That’s why the robot must be outfitted with a flipper system to intake and deposit blocks. It’s the only design that will make it to the world competition, and it’s the only way that we will make it out of local competitions. I personally have taken it upon myself to develop the prototype while the majority of the team is focussed on a new grabber arm.

    While our grabber arms were *good*, they weren't great. The arms currently attached to the robot, which use the turkey-pans, didn't grip as much as we hoped, and while we're designing a new version which has specialized 3-D printed arms, we can't put all our eggs in one basket. So, we decided to make the flipper system. The advantages of the flipper system as compared to the other systems is that the flipper system:

    • Does not depend on friction to hold blocks
    • We had previous issues with block slippage with the arms model, and this should fix our dependency on high-friction materials.
    • Faster
    • Our old arms depended on stacking to get more than one block, while this one wheels blocks in, reducing the time needed.
    • Less precision needed
    • Before, we had to align blocks directly with the arms to pick them up, but this can just use the wheels to intake blocks.

    So far I have built a flipper and an intake system, both that function well, but have yet to get the teams’ permission to attach it directly to the robot, as it would require a lot of dismantling. Since it won’t be able to be put on before the upcoming Wylie qualifier, it’s been put on a backburner as I also throw myself at the new grabber arm. The flipper is being held in a frame I built around it but as a system is comprised of a board attached to a servo attached to a drawer slide that works as a vertical lift. The intake system is composed of two intake wheels made of the same foam tiles that make up the field floor attached to two axles that are chained to two opposite rotating gears powered by one of the new REV motors. The intake works with the flipper well and only needs some side guards. I’m half of the way through designing. It should be on the robot before any regional qualifiers we go to.

    Chassis Model

    Chassis Model By Abhi and Janavi

    Task: Use Creo Parametric to CAD the chassis

    After making significant development on our robot, we decided to model it. So far, we have developed the chassis of the robot seen below

    To develop this, many types of contraints were used.

    The entire model is dependent on this tetrix bar. The bar was constrainted using the Default feature since it was the base of the model. To this, the lift motor was attached as well as the battery box. These two were constrained by the Distance feature to the end of the bar.

    Four REV rails were attached to the TETRIX bar. These supported the wheels and their motors. They were constrianed through the Coincident to the bottom of the tetrix bar and Distance to the side of it.

    There are custom designed motor mounts constrained to th side of the REV rails using Coincident and Distance measurements. To this, there are TETRIX wheel mounts attached onto which the mechanum wheels are attached. On the outside, wheel guards were attached. The motors that drive the wheels are attached to REV motor mounts which were constrained to the underside of the REV rails. Attached to the motor is an axel which connects to a sproket to turn the wheel.

    The REV hubs were the hardest to constrain in this model because they didn't have typical sides. To mount them, we used a combination of Distance, Coincident, and Angle Offset features. The final part of the model was the phone mount which was simply constrained using coincidents.

    The next steps of this robot is to complete the robot model. This chassis was actually reused from last year. Due to licensing issues, we had to redevelop this model. We hope to experiment with this model to make space for the new, larger gripper arms.

    Fixing the Robot Chassis

    Fixing the Robot Chassis By Austin

    Task: Redesign the robot chassis, fix issues

    When we designed our new grabber with the octopuckers, one of the variables we neglected was the width of the new grabber once assembled and resting. After the grabber was completed it’s width was actually greater than that of the housing bay we had built into the current drive train, so to get the grabber to fit we actually had to widen the bay. We had know from past experience that the base was never truly square, so we took this necessary widing as a chance to resquare the base and drastically improve the efficiency of our mecanum drive. We added ¾ inch to the inside base and the resquared the frame before finally bolting everything down and attempting to mount the new grabber. Because the closed grabber barely fit within the new widened bay we had to cut away portions of the frame over the front wheels to allow the octopuckers room to actuate.

    The other key chassis modification needed to accommodate the new grabber system was a lift bolstering. We decided that to handle the newly doubled weight of the grabber we would share the load across two strings and convert to a double pulley system. The lift was also strengthened with newly squared and adjusted cross beams similar in length and angle to the other iteration. Because of the double pulley, we also centered the drive motor and utilized a second spool. The pulleys rest on either side of the lift system and are both being run by the same motor.

    The Grabber V. Kraken

    The Grabber V. Kraken By Austin and Evan

    Task: Build a new version of the grabber

    One of our issues with the previous iteration of the gripper was the fact that the material that coated the actual pincers weren't even and would often lead to blocks slipping from the bottom of the gripper and falling out. Our solution to this was to retest materials and in this process we decided to try our hand at 3D printing a circular and pliable material that could be part of our new rotating pincers. We designed the OCTOPUCKERS and built the rest of the grabber around that. Because the octopuckers were designed to slide onto typical rev-rail extrusions we also had to design a new system of bearings that could house the rails with skewered octopuckers.

    We developed a “revolutionary” new 3D printed rev-rail bearing system that was liked with a series of chains and pulleys that could be attached to our current lift system and not severely alter the base and drive train. Previously the grabber was actuated via a system of servos controlled by a rev hub back on the main drive train, however in this newer iteration of the grabber, we decided that all of the necessary wiring would be kept inside the grabber to eliminate tangling by mounting the rev hub on the back of the grabber. While this grabber was a major upgrade that drastically improved our glyph handling capabilities, it did in fact double the weight that our lift had to bear.