Following on from our last post, we’d like to provide an update: the custom computer desk for Gil Addison at PathPoint was recently delivered, bringing that particular project to a close. This desk raises up and down to any given height using an electrically driven linear actuator. The wheelchair user carries the remote control key fob, allowing complete adjustment from near or far. The desk is intentionally designed to tip the computer forwards to face down towards the user, as many wheelchairs seat the occupant in a reclined position.
At the time of this writing, we are still waiting for feedback on the end result and photos of the desk in action. But in the meanwhile, enjoy some photos of the students as they put together the final product and examined the results. Thank you, Gil, for helping us execute such a meaningful project!
The final product assembled in the workshop, after some final modifications. The actuator placement had to be changed in order to create more torque to lift the table.
After disassembly, Nolan (senior) set to work applying the protective oil to the upper table surface
Abby (freshman) oils the lower base piece
After all pieces were oiled, Angel (sophomore) reassembled the entire structure together with Mr. Meadth
A few more bolts to go–almost there!
The finished product as attached to a typical household table, keyboard shown
The finished product in the full lowered position
Teleios, Hunter, and Abby (freshmen) get their first look at the end result on the day of delivery
Joshua and Nolan (seniors) test out the remote control
The whole team from left to right: Hans, Abby, Hunter, Teleios, Mr. Meadth, Angel, Joshua, and Nolan (James was also in this group); note an iMac computer attached as per intended use
Even in the midst of a global pandemic, the Providence Engineering Academy follows a particular philosophy that transcends circumstances. While many robotics clubs and engineering programs might teach physics, maker skills, CAD, and more, we believe that these elements—”fascinating as they may be—are only the means to an end. In the latest application form for the coming year, there are six “big ideas” listed; Big Idea Number 1 is that service matters:
As Christians, we have an obligation to turn our skills outward to the world around us; we learn not for our own sakes.
While we may not be allowed to mix cohorts or share equipment, the seventeen dedicated upper school students are committed to loving their community using their math, physics, coding, CAD, robotics, and maker skills.
Early on in the school year, we found two willing partners in this process: one was Mr. Gil Addison of PathPoint, an organization serving at-home and on-site residents, many of whom use a wheelchair each day due to their limited mobility. The other was Mrs. Christa Jones, 4th Grade teacher in the Providence Lower School. Both of these clients had distinct requests for custom-made furniture and it was the perfect opportunity for our students to put their new-found statics knowledge to the test (statics is the study of physically balanced situations where the net force is zero, such as buildings and bridges).
Mrs. Christa Jones, 4th Grade Providence Teacher
Mr. Gil Addison, PathPoint
Mr. Addison wanted a custom-made desk for an iMac computer that could be set to a lower height for a wheelchair occupant, and then back up to a standing desk height for an ambulatory user. Such a desk is hard to find in the current marketplace, and the engineering students saw an opportunity to provide something uniquely useful. The desk would be mechanically driven by a remote control, safe for an individual with limited dexterity, and functional to hold the computer at any height without concern.
By contrast, Mrs. Jones needed a new teaching desk at the front of her room to help meet the new style of a COVID year. This mobile desk would need to be equally useful in a standing or sitting position, for maximum versatility with her in-person and at-home students.
How to meet the needs of these clients in a year when the Engineering Academy is functioning in an independent-learning mode? How could we hold a meaningful design charrette when mixing between cohorts is prohibited? How can seventeen students come up with an agreed-upon detailed design and communicate it with the clients?
Answer: with creativity, technological tools, and a great attitude!
The students began by watching pre-recorded videos from the clients as they described their requests and necessary constraints to Mr. Meadth, the Academy Director. Mr. Meadth offered up some quick sketches and ideas in the videos to help sort through what would and wouldn’t work.
Early notes for Christa Jones’ project
Early notes for Gil Addison’s project
The students then used LEGO and other construction materials to make quick miniature mock-ups of their ideas, along with sketches to help show functionality. The images were sent to the clients to help them think through the possible solutions at hand. Another round of recorded video reviews with the clients, and then the real design work began!
Alan’s rolling cart concept
Kaitlyn’s desk concept with extendable platforms
Together with Mr. Meadth, the students worked together over Zoom and in their grade level cohorts, using the cloud-based CAD tools from Onshape. With each student taking ownership of several parts from the whole, they worked collaboratively to produce something that could be presented back to client as a visualization and to the fabricator as dimensioned drawings. Teleios in 9th Grade can create the top part of the desk, Angel in 10th Grade can make the support struts, and Nolan in 12th Grade can design the platform for the keyboard. All team members can see how the pieces fit together in advance, spotting potential problems before a single cut is made. This kind of ease, speed, and confidence in the design process simply did not exist even five years ago, and we are glad for it!
(The computer desk for Mr. Addison can be viewed live here, and the rolling cabinet for Mrs. Jones here. Both models are interactive.)
Mrs. Jones’ rolling cart CAD model
Mr. Addison’s adjustable computer desk CAD model
So where are we today? After purchasing the plywood, oak, mechanical actuators, caster wheels, and other bits and pieces, fabrication is underway. The clients are now eagerly awaiting the delivery of their prototypes. Gil Addison’s computer desk is nearly complete at the time of this article, and Zach in 11th Grade has put together a beautiful biscuit-joined red oak desk surface for Mrs. Jones’ rolling cabinet.
James assembles the clamping mechanism for Gil’s design
Teleios and Abby show off the parallel linkages
Nolan with the mechanical actuator
The vision nears reality for PathPoint!
Zach’s red oak table surface (3 ft long)
We’ll update this blog site as the projects are completed and delivered. For now, we’re just glad to be able to continue our exciting mission through a pandemic and out the other side. The exhortation in I Peter Chapter 4 seems particularly apt:
Each of you should use whatever gift you have received to serve others, as faithful stewards of Godâ€™s grace in its various forms. If anyone speaks, they should do so as one who speaks the very words of God. If anyone serves, they should do so with the strength God provides, so that in all things God may be praised through Jesus Christ.
Keep on serving with the strength God provides, engineering students! You’re making us all very proud.
There hasn’t been a lot of action on this blog site so far this school yearâ€”but not because there aren’t things worth writing home about! As you can imagine, I (Mr. Meadth) have been much busier on the ground each day with cleaning and supervision, let alone teaching the engineering class.
But some things are worth documenting and celebrating. So let’s jump in!
1. Four New Freshmen
We took four new engineering students into the freshman class. A big welcome to Hunter, Abby, Teleios, and Eliana. These junior engineers are hitting the ground running, despite all the challenges. They are learning trigonometry before their time, taking baby steps into the world of computer-aided design (CAD), and just generally being awesome. Welcome, freshmen!
Hunter, Teleios, and Abby (Eliana couldn’t make this photo, but she’s just as much a part of this group!)
2. College-Level Statics… From a Textbook
Despite my propensity to always design my own curriculum from the ground up, I tried something new this year: a textbook! It turns out this was the perfect year in which to do this, as it matched well to the statics studies that we’ve always done anyway. Don’t be led astray by the nameâ€”Statics for Dummiesâ€”the lighthearted tone helps high schoolers get through those pesky equations. For those engineering parents out there, you’ll find all of the fun you can handle in vector calculations, force couples, and free-body diagrams.
3. Independent Mode
This is a grand experiment, and one that we committed to from the start of the year. Can we commit to a full year of engineering studies in independent mode? Some would say that it’s never been tried, but this is the year to come up with new solutions! Despite the absence of stimulating classroom discussions, this has allowed students to take seven classes plus engineering, and it allows students to watch at their own pace. Students have watched 18 videos so far this year, and responded with written assignments and discussion boards. They are now eagerly discussing their community design project in a shared Google Doc, which brings us to Number 4…
Acceleration sums in three dimension, anyone?
If you can’t find the centroid of a composite area, you just can’t call yourself an engineer
4. Community Design Project
I’m so happy with how this project is rolling forward! We have two “clients”, Mrs. Christa Jones on the San Roque campus and Mr. Gil Addison at PathPoint, who works with residents in wheelchairs. Our student teams are busily designing an adjustable standing desk for Mrs. Jones and an adjustable computer desk for Mr. Addison. Both of these designs are required to involve electrical/mechanical aspects, such as motorized lifts or built-in LED lighting. Once the student teams finalize their designs, complete with drawings and CAD models, I (Mr. Meadth) will be building their designs myselfâ€”in the interest of staying as contact-less as possible.
5. Lots of Publicity
We’ve received a surprising amount of national-level publicity lately. Our students use the CAD platform Onshape, and Onshape reached out to us to record a video and write a blog article. The video has been up for a over a month now, and the blog article will be published soon. Our Academy was also mentioned in another national publication by the American Institute of Aviation and Aeronautics (AIAA), Aerospace America, because we won a $500 grant to help build our remote-controlled aircraft.
6. Major Grant Win
Is it just me that believes in our outstanding Providence engineering program? Is it just the university lecturers who receive our already-highly-trained students? Am I just blowing my own horn over here? Apparently not! The Toshiba America Foundation decided that our second-semester robotics project was something worth funding, and we are pleased to announce that over $4,000 of the very latest in classroom robotics equipment will soon be arriving on campus. This will be put to use in our Mars Rover project, where different student teams will design, build, and code different components of one big vehicle. I’m looking forward to this one. Thanks, Toshiba!
One of the advanced Vex V5 sets: coming soon!
As always, stay posted for more exciting announcements. Our junior engineers are doing something very different, but making the most of it. I’m confident that their skills and experience will remain at the very highest level amongst similar programs in our area. Keep it up, students!
You can’t choose the hand you’re dealt, but you can play it to win every time.
Along with every one else around the globe, the Providence Engineering Academy was dealt a tough hand in March. Having worked so hard in the lead-up to the major capstone projectâ€”to design, build, and fly a powered tethered aircraftâ€”being asked to complete the project from home was not the situation that anyone wanted. But in the spirit of problem-solving, our junior and senior engineers faced up to the challenge. After all, what is engineering all about if not solving problems?
Our last post on this project ended with the four teams designing various aircraft components using professional-grade CAD software. They had sent their designs to Mr. Meadth, who began to 3D print their fuselages and tails, cut their carbon fiber, and CNC mill their wooden wing ribs, all from the comfort (?) of his garage.
The garage workshop: where the magic happens!
Over the course of several weeks, each team’s delivery bag in the garage began to pile higher and higher with these manufactured components, along with advanced electric motors, lightweight lithium batteries, tissue paper, and other bits and pieces. Every last one of these components had been accounted for in duplicate: in a virtual CAD model and a complex spreadsheet. The CAD model held the actual design for manufacture, visualization, assembly guarantee, and mass/center-of-gravity prediction. The spreadsheet calculated wing and tail lift, which in turn yielded a force and moment balance, and also a redundant center-of-gravity prediction. (Redundancy is not a negative word in aircraft engineering!)
Quick science lesson: the center of gravity (c.g.) is where the sum of all weight is located. In other words, it’s the point at which you could balance the aircraft on your finger, or where you could hang it from a string. It is determined by the masses and locations of the individual components, and it was critical that our uncontrolled aircraft had the center of gravity forward of the wing’s lift force. Without going into the deeper explanation, having the center of gravity as close to the nose as possible means that the aircraft will be self-correcting and stable as it flies. Try attaching a paperclip to the nose of your next paper aircraft and note the dramatic improvement! This is why we ran two separate c.g. calculations using two different methodâ€”we wanted to absolutely confirm before manufacture.
Fresh off the printer, ready for delivery!
Sam and Josh work on RUBYGEM, papering and doping the wings
Mr. Meadth delivered each team’s bag directly to their respective homes. Upon arrival, each team worked hard to assemble the aircraft. This involved inserting carbon fiber spars into 3D printed wing boxes, stringing the wooden ribs evenly along the spars, covering the ribs with tissue paper, and then applying dope (a kind of water-based glue) to the paper. The doped paper dries and hardens into a kind of thin shell. The various electronics components were also connected and secured, along with the tail and undercarriage (landing gear).
At the same time, the simple tethering system had to be designed and implemented. The wooden stand sits in the middle of the flight path, and a 3D printed bearing served as an anchor point for the tether line. The tether was then attached to the wingtip. Some of the aircraft needed a little more rigging to ensure that the centripetal force didn’t rip the wingtip loose!
Fast forward to the big day. Mr. Meadth made a final decision to hold the test flights in the gym, instead of outside. The smooth floor would take one more variable out of the equation, and the enclosed space would keep out any stray gusts. When your plane only weighs about 2 pounds and floats on the breeze, a gentle wind can be your worst enemy!
Thanos steps on to the court!
First up to the plate was Nolan and Pedro. Their purple and grey monoplane had a planned weight of 800 grams (less than a liter of water). The wingspan was a fairly standard 1.06 meters (a bit more than 3 ft), with a conventional tail style and taildragger undercarriage. Mr. Meadth tied their aircraft to the tether as the excitement mounted, and Pedro took the first turn at the controls. A gentle increase on the electronic throttle, and the affectionately named Thanos rose up beautifully into the air! Nolan took a turn as well, and the team scored two successful take-offs and two successful landingsâ€”the ideal outcome!
Plan view of Thanos, taken from the CAD model
Next up was Madison and Alena. Their Airplane Baby was ready to take its first steps, with Alena at the helm. In various shades of baby blue, the 540 gram winged wonder stretched out at an impressive 1.2 meter span (about 4 ft). Their wing aspect ratio (the ratio of wingspan to chord length) was a very healthy 12, almost double that of some other teams. But would it fly?
Airplane Baby gets ready to roll!
The girls produced a set of plans for their written report
Without a doubt! Both Madison and Alena toured the gym in a somewhat rollercoaster fashion, the tether line being stretched to its limit. We estimated just a couple of feet clearance between the aircraft and the wallsâ€”enough to make any pilot sweat a little! But after a safe landing, all was well.
And now a little math. Replaying the video, it looks like Airplane Baby took about 3.5 seconds to complete a lap. If the diameter of the circle was about equal to that of the basketball court (50 ft), then the radius of the circle was half that: 25 ft. The speed of the aircraft through the air is equal to distance over time; the circumference of the circle divided by the time to get around that circle.
Circumference = 2Ï€ Ã— radius = 157 ft
Speed = distance/time = 157/3.5 = 45 ft/s
This was about 36% faster than their design speed of 33 ft/s, which only goes to show that their stable aircraft design works just as well under a variety of situations. (It may also mean that their wings weren’t as effective at generating lift as theorized!)
Sam and Joshua took to the floor after that, with a slender red aircraft tied to the tether: RUBYGEM. With a planned mass of 440 grams (almost exactly one pound), this was the lightest plane on display. Their rectangular wing planform spanned 1.08 meters, and they planned to fly at only 8 meters per second (26 ft/s). A lighter aircraft does not need as much lift to stay in the air, and so for any given wing design, it can fly slower and still generate the force it needs.
RUBYGEM steps out in style
As RUBYGEM gracefully lifted into the air, it was obvious that she indeed favored a slower style of things. Completing each lap in almost 5 seconds, the flight speed can be calculated at 33 ft/s. This is also faster than their design speed, which reinforces the theory that perhaps there is more inefficiency in the design than our theory accounts for. Sounds like real life, all right!
After successful landings, Mr. Meadth made the decision to head outside with the fourth aircraft: Big Wing Boy. And boy, was it big! At over 2 meters (6.5 ft) span, this multi-colored monoplane was just too big to spread its wings indoors. It was also designed to fly a little slower, and was very light for its size: 800 grams.
Big Wing Boy, taken from the design report
There was, however, one significant issue: while the design looked good in the CAD model and spreadsheet, the greater spans and sizes meant the physical attachment of the parts was just that much more difficult. The sheer size tended to stress the wing root joints more, so extra tension lines were strung between wingtips to help hold everything together.
Being outdoors on the grassy field, the decision was also made to give the aircraft a running hand-held start, because the wheels get caught in the grass. Risky? Yes! Mr. Meadth held Big Wing Boy aloft and kicked off his shoes to get the best launch speed possible. Given that an Olympic runner travels at around the 10 m/s mark, finding the necessary design speed of 8 m/s would be a challenge!
Ben cranked the throttle to a healthy roar, and Mr. Meadth began to dash around the circle. With a final push into the air, B.W.B. lifted up into the great blue yonder where he belonged. All seemed well… and then the unthinkable! Video footage analysis confirms that the carbon fiber stick connecting the wings to the tail tore loose from the aerodynamic loads, and no plane can ever do well without that stabilizing influence. This principle was, in fact, one of the central pillars of the second semester!
The moment of horror as the tail comes loose!
The aircraft wanted to perform, but just couldn’t remain aloft. It plowed into the grassy field after only a few seconds of genuine flight. A quick repair and a repeat attempt was launched shortly thereafter, but another half-lap was achieved with similar resultsâ€”with more permanent destruction this time! There was no third flight.
At the end of the day, what did we learn?
Challenges are there to be overcome. The project could have modified to be easier, simpler, more virtual, you name it. But that kind of logic doesn’t get you into the history books, and doesn’t give the same kind of satisfaction. Greater levels of determination can turn challenges into victory.
Theory is useful, but doesn’t account for everything. Math and physics equations and computer simulations are incredibly useful, and with high-level manufacturing can be a very good analogy of the intended outcome. But the fact is that our theoretical calculations didn’t account for a great many factors. This makes it all the more important to create robust, stable designs. The aircraft didn’t perform exactly as intended, but they did perform in the real world.
Aircraft need firmly attached tails. You may want to check the welds next time you hop on board your next 737.
Congratulations to our eight aircraft engineers, and many blessings on the four seniors, now alumni: Ben, Todd, Alena, and Madison. You have completed something to be proud of!
Our students can’t be together in person right now, but nothing is going to stop them finishing the capstone design/build/fly project for the 2019-2020 year. With digital tools in their hands and computer-controlled manufacturing equipment at the other end, our budding engineers, now sheltered in place, are experiencing the reality of a modern workflow. Even before the advent of COVID-19, many companies routinely collaborated from around the globe, producing advanced designs using international teams. Although not our first choice of preference, we’re taking the challenge head-on!
Mr. Meadth teaching aircraft stability via Zoom
The first step for our skillful students was to learn the ins and outs of classic aerodynamics. In January, February, and March, the eight juniors and seniors studied airfoil behavior, lift and drag equations, and learned how to use weighted averages to find the center of gravity of a complex system. Our team learned the different parameters of airfoil design, and used virtual wind tunnel tests to predict just how those airfoils would respond in real life.
The virtual wind tunnel program XFoil: a classic historical aerospace simulation! Note the cambered airfoil shape at the bottom, with the yellow boundary layer on top and the blue one below
Even more important was the notion of stability. What makes some physical systems stable, and others unstable? The incredible hexacopter drone that emerged in the first semester was inherently unstable, which means that it will rapidly flip and roll and fall out of the sky if the onboard computer-controlled gyroscopes were to stop doing their job. The gyroscopes sample the position and orientation of the drone dozens of times per second, and send minor corrections to the six motors, all without the pilot on the ground ever knowing it. Stable drone flight is an astounding human accomplishment, powered by calculus and implemented by technology, but it is not inherently physically stable.
On the other hand, the powered fixed-wing aircraft in this project must be physically stable. Tethered to a central post and flying continual circles, the aircraft will have only one remote-control channel controlling the power to the motor. There are no ailerons, elevators, rudder, or flaps. Without moveable control surfaces, the aircraft must be designed to constantly self-correct all by itself. If the nose dips down a little because of a gust of wind, it must automatically seek to find level again. If it rolls a little too much to one side, it needs to roll back again. The principles involved hold true for most common vehicles: cars, bicycles, even the caster wheels on supermarket carts.
Having mastered the physics involved, the students set about the difficult task of starting their design. No kits, no instructions, no fixed starting point! In teams of two, the students created a complicated spreadsheet filled with graphs and tables and physics equations, listing masses and locations and forces and moments. The students also designed a multi-part CAD model according to those numbers using the professional-grade online platform Onshape; ideally, the CAD model, the spreadsheet design, and the manufactured plane itself will end up as three matching representations of the same reality.
Pedro’s and Nolan’s aircraft in its complete form
The same aircraft in an exploded view
Mr. Meadth ordered in the necessary tools and materials for construction: carbon fiber bars and tubes, balsa wood, lithium-ion batteries, electronic speed controllers for the advanced motors, propellers, wheels, and filament for the 3D printer. These materials were fully paid for by a generous grant from AIAA, the American Institute of Aeronautics and Astronautics. AIAA believes strongly in encouraging the work done by K-12 schools in advancing aerospace education, and Providence School has received similar grants in the past.
The delivery of the critical components arrives!
Through the COVID-19 distance learning experience, the four teams produced their designs without ever meeting in person with each other or the teacher. Because of Zoom lessons, shared spreadsheets, and the powerful collaborative nature of Onshape, this project didn’t skip a beat. Mr. Meadth set up a manufacturing station in his own garage, and busily set to work producing what the students had designed. The CNC (computer numerical control) machine carved out flat balsawood ribs with exact length, thickness and camber dimensions, and the Raise3D 3D printer produced the three-dimensional components such as fuselages and tail.
The Providence Engineering Academy manufacturing facility!
A completed wing rib from Ben and Todd, with carbon fiber spar inserted
The vertical tail for Nolan’s and Pedro’s aircraft, over nine hours in the making!
The huge 30-hour print of the fuselage/ wing box (lots of temporary support material can still be seen
Ready for clean-up, delivery, and assembly! The motor and one propeller option are in the background
Where to from here? The Advanced Engineering II students will receive deliveries of their manufactured pieces, to be assembled at home. Test flights, possible redesigns, and the final maiden voyages are scheduled to happen in late Mayâ€”stay posted for the culmination of this exciting story!
(The fifth in our student blog series, written by Sam in 11th Grade, is followed by the teacher’s two updates on the project, so please read all the way down! Flight tests were finally successful, as students and teacher alike learned the hard realities of “going back to the drawing board!”)
While we donâ€™t plan on taking him to the sun, Icarus was the name we selected for our massive hexacopter drone. With a 31-inch diameter, and the theoretical ability to lift almost two pounds on top of its own five-pound weight, it is operating at the higher end of recreational drone constraints. Most commercially available drones today feature only four propellers, and a mass of around one pound.
Early sketches of the design, with design priorities listed on the side
When we were designing â€œThiccarusâ€ we decided to push the boundaries with the materials we had available. A hexacopter design, as opposed to a more common quadcopter (a standard recreational design with four propellers), gave us more lift power and stability with a trade off on speed and maneuverability. To reduce weight and maintain strength Thiccarus would be constructed with 3D printed body parts and carbon fiber struts connecting them. However, when we were brainstorming, we decided that our droneâ€™s primary function would be cargo delivery (despite my suggestions to make it into a fishing drone or a laser-toting drone with a search and destroy mission).
Pedro, Nolan, and Joshua tear apart old quadcopter drones from two years ago–fare thee well!
We came up with our design, then our constraints and requirements. After this, we split into design teams, each headed by â€captains.â€ After the protective shrouds around each propeller and control center base were decided upon, we set to starting a joint Onshape project. Onshape is our 3D design platform of choice for this project. Each team member was assigned one component of Thiccarus to design, and it came together well in a collaborative fashion. Each member of the design team is able to see in real time how their part will integrate with the other parts, which is incredibly helpful.
The eight students work concurrently on the drone CAD model, with each one instantly able to see how their component fits into the broader scope
The hexacopter design emerges!
The largest and most difficult piece to print: the central electronics platform; five or six attempts at printing were required
Icarus is currently in the printing stage, and when it is fully constructed, it will be mounted with two cameras feeding to a battery powered LCD screen. Steered by the controller, it will be capable of flying high and low to deliver small payloads.
(Sam’s article was written in early October. After a delay in printing production due to some technical difficulties, the entire drone was finally fully assembled and taken for some early test flights. And now the updateâ€”which gets a little technical…)
After many hours of printing and assembly…
Sam, Ben, and Todd carefully attach the motors and batteries and other electronic components
The 8th Period engineering class proudly marched their huge drone out to the Providence soccer pitch. Gentle (and safe!) power-ups in the classroom had proved troublesome, with erratic behavior being immediately apparent. The drone was very touchy, and tended to spin around and roll to one side. Cutting the throttle from even six inches of altitude caused the aircraft to fall with a ungraceful “thump”, with small 3D-printed pieces occasionally breaking off.
Alena gave an insightful suggestion that we could take it outside and stretch out a big sheet of fabric to catch the drone as it fell. This would allow us to try to gain more altitudeâ€”and more time to evaluate its behavior and get it under manual control. The soft fall into the fabric would certainly keep both drone and students completely safe! As an added bonus, we would look comically like cartoon fire-fighters.
The group heads outside to try an initial flight: safety goggles on!
And look like cartoon fire-fighters we did! The plan worked rather well, except for Ben slipping accidentally in a mud patch on the field in his zeal for saving the drone. With the extra flight altitude and time, we learned that the machine wanted to spin on its vertical axisâ€”absolutely out of control. Where it should have lifted gingerly into the air and hovered obediently, it was a veritable whirling dervish, and the group could not even agree on their recollection of whether it had spun clockwise or counter-clockwise!
It may look like the class is flinging it into the airâ€”we promise it is actually flying!
In a typical situation like this, the pilot should be able to add in some “yaw” trim. This means that the controller is set to always provide a little bit extra of yaw control, intended to counteract whatever is naturally happening and make everything balance out again. But adding yaw trim in either direction just didn’t change anything, and after one particularly wild spin the drone fell outside of the fabric and broke one of its 3D-printed propeller shrouds.
See that tilt to one side? About three seconds later Thiccarus successfully escaped our circle of friendship!
Back to the drawing board…
It is possible that the flight controllerâ€”the 1-inch small box that houses gyroscopes and inputs and outputs and magnetometers and so onâ€”is just misbehaving or badly calibrated. But after several recalibrations and trying an alternate one that we had in stock, there was no improvement. Check.
Is Thiccarus just way too “thicc”? Maybe. We could have designed more aggressively, and perhaps brought him down to 2 kg even (4.4 lb). But the specs say that each motor should be able to create up to 550 grams of thrust. With six motors in total, that’s 3.3 kg of thrust available (7.3 lb). And it’s definitely getting off the ground, even with the thrust output turned down for safety. So: check.
It is possible that one or more motors are just misbehaving or getting bad signals. Tiny, threadlike wires carry the commands between the different components, and we have run into problems of this nature before. But replacing one bad cable fixed that, and simple individual motor bench tests show snappy, responsive motors that will blow your papers away from across the room.
When all else fails, Google it. Apparently, when your drone experiences untrimmable yaw, it is likely the result of not having set all motors perfectly level. In other words, one or more propellers might not be perfectly flat relative to the ground, but tilted slightly to one side. And yes, this is quite noticeable on poor old Thiccarus once you look for it. Fortunately, it can be easily solved by readjusting the four screws that hold each motor down, and putting a little “shim” on one side to nudge it up to level.
This is actually an interesting application of standard high school trigonometry. If a thrust vector is pointing straight up to sky, well and good. This is what the flight controller is banking on for its power distribution calculations. But if a motor is tipped to one side by even two or three degrees (barely perceptible to the eye), the aircraft will experience a mysterious lateral force equal to the thrust times the sine of the angle. If the motor is generating a healthy 500 grams of thrust (a little over a pound), three degrees of tilt creates 26 grams of sideways thrust (500sin3Â°). Small but significantâ€”and the flight controller is not accounting for it.
Maddening: yes. Fixable: absolutely. The motors will be checked and adjusted, and Thiccarus will be bandaged up and flown again. It is also very likely that a Mark II design will surface in the second semester, with higher tolerances for motor angles accounted for from the very beginning and a lighter airframe. Less airframe weight means longer flight times, a more responsive drone, and a greater possible payload.
Providence Engineering Academy: carry on!
(Our final update for this story on the 19th of November. Spoiler alert: it’s a happy ending!)
As promised, the motors were checked and adjusted. Ben and Mr. Meadth stayed after school and carefully placed pieces of card under this or that side of the motors to shim them up, bringing them as close as possible to vertical. Three motors were in need of adjustment, but none of them were out of line by more than about two or three degrees. The drone was powered up, with high hopes… but the end result was exactly the same. Thiccarus wanted to flip over to the side and rotate faster and faster, and nothing could persuade him otherwise. Forget flying too close to the sunâ€”Thiccarus couldn’t even get off the ground!
Mr. Meadth had his flash of inspiration, and it all came down to this image:
The source of all problems.
This diagram shows the initial wiring and setup instructions from the flight controller. A certain teacher thought he had carefully followed the diagram; unfortunately, he had set the actual propeller directions all opposite. For example, propeller 1 was supposed to be rotating clockwise, but it had been set up to be counter-clockwise.
What’s the big deal, you ask? Well, while having everything opposite would still be balanced to some degree, the flight controller uses the spinning propellers to control its yaw. Say the craft wants to yaw to the left, it chooses a propeller to spin faster to the right (like propeller 1), and Newton’s Law of Reactions takes over. If it wants to yaw to the right, it might choose a left-spinning propeller to do that (like propeller 2). But since each and every one was backwards, the corrective actions it tried to take were in every case making the situation worse. If it started drifting left, it would end up spinning more leftâ€”a classic vicious circle if ever there was one.
A quick click of a checkbox in the computer and that was solved. All propellers: backwards. Oops.
Propellers… spinning the correct way!
You know you’re doing something right when you’re looking at the bottom of the drone
This portable outdoor screen receives video input from two onboard cameras
Today marks another successful series of flights. We currently get about ten minutes of air time with two fully charged batteries. Three students plus teacher have been brave enough to fly around a little bit. No major accidentsâ€”perhaps a leg snapping off here or there with a rough landing!
Persistence pays off. If this is a thing that can be done, then you can do it. Just get out there and keep troubleshooting until you work it out.
This is a new era of high school education. To collaborate on a CAD model, 3D print it, order the electronics, and create a hovering 2.2 kg monstrosity in the space of three months is just not something a school could have done in-house ten years ago. Truly these are amazing times!
These students are capable. With the right leadership and direction, they know how to think and problem solve and calculate and design. They will go far.
The story ends here, but keep an eye out for Mark II! We just can’t resist. There are already so many things that could be optimized (chiefly, stronger airframe and lighter weight). Lighter weight means more air time, so bring it on! Look out for Son of Thiccarus in the second semester, and until then, stay posted.
(The fourth in our student blog series comes from Nolan in 11th Grade, and gives the final update on a project that was begun last year.)
Last year, the focus of the Advanced Engineering I group (juniors and seniors) of the Providence Engineering Academy was statics, or the branch of physics associated with objects at rest. As a way to explore this topic, the members of the Engineering Academy collaborated with the Providence Physical Education Department. Their goal was to create versatile wooden boxes that could function in many different ways: an obstacle course, a balance beam, or a step-up box, for example. In this way, the engineering students created a system that would not only benefit the P.E. program, but would also help them learn more about statics, since the structure would have to be able to withstand the use of the junior highers (not breaking or sliding on the grass when jumped on, while having multiple uses).
The first box shown in a virtual assembly
The second box shown translucent, interior strength wall visible
This first step of this project was to create paper models of the boxes, to see how everything would fit together. After Mr. Meadth, the director of the Engineering Academy, approved the designs, the team shifted to using an online program called Onshape. Onshape is a design tool used to create realistic models of objects. This CAD technique allowed the budding engineers to visualize their designs of the boxes further and make adjustments where needed. Once the â€œCADingâ€ was complete, it was time to start producing and assembling the actual boxes.
Mr. Meadth checks the fit of the first two pieces of one box, as students look on
The students wrestle with the heavy pieces, sliding them into place
Incorporating the â€œbox jointâ€ technique (resembling a three-dimensional puzzle, used for strength), the two large boxes were finally completed after lots of hard work from last yearâ€™s juniors and seniors. Each box comprised approximately nine pieces, weighed about 120 pounds, and had volumes of 80 and 48 cubic feet, respectively. Another fun touch added to these boxes was a grid of four inch squares cut into sides of the boxes, allowing them to be connected together with beams. These boxes are oddly shaped, one like a cube cut along the diagonal and the other like a cube with a rectangular chunk missing, which only adds to their versatility.
An almost completed box, missing two faces and the inner wall
Fast-forward three months: two amazing boxes just as planned!
Since these boxes were created last year, they have had much use from the junior highers. Mr. Mitchell, the P.E. teacher, says that he is â€œvery grateful that the Engineering Academy did this,” and that “these boxes really enhance the fitness pursuits and the program as a whole.” Judging by the frequency of use and Mr. Mitchell’s gratefulness, this project was a resounding success. Great work, Providence Engineering Academy!
A grateful Mr. Mitchell urges his students on as they create innovative workout routines
(Our latest blog article comes courtesy of Joshua in the 10th Grade. Thanks, Josh!)
In the event of an emergency, robots may be called upon to enter into areas which have been devastated by natural disaster. The thirteen students from the Foundations of Engineering II class split up into four groups to build such robots, and testing came after eight weeks of work and dedication!
The original CAD model of the obstacle course, constructed over several weeks by our indefatigable teaching assistants, seniors Josh and Claire
The testing included nine phases (any of which could be skipped) all while carrying a payload. The teams would go through two gates of different sizes, over a gravel pit, up onto platforms of varying heights of 50 and 100 mm, push a block with the mass of one kilogram, go across a chasm, and make their way up a 45Â° incline. At the end of the run, the robot would be required to drop off the payload. The driver for each team would first do this routine while watching from nearby, and then once again using only a first-person camera view.
Davis gets his team’s robot up onto the 50 mm platform with no worries at all
The first robot to test was the “Trapezoidal Tankâ€. This robot was built by Nolan, Davis, and Alan. They felt ready for the first trial of the course, but decided to skip the 45Â° incline. Everything ran smoothly until the payload drop at the very end. They realized something was wrong.
The payload mechanismâ€™s motor came unplugged!
Davis, the driver, thought up an idea. The payload was resting on top of the robot. What if he just flipped the whole robot over? Using the tankâ€™s “tail”, he flipped the robot up onto its end and delivered the payload.
Although not able to climb the full 45 degree slope, with a slight modification the Trapezoidal Tank was make it at 40 degrees
A moment of pure glory! Davis upends the entire robot and performs the obligatory victory dance!
On the camera-only run, the course was successfully completed again with only one obstacle skipped.
Caleb taking things in his stride, as the long-legged robot effortlessly clambers over the gravel pit obstacle
Caleb attempts to steer by camera only– no easy feat!
Pushing the one-kilogram block away, the package waiting to be delivered is clearly seen on the right-hand side of the robot
This complex (and squeaky) maneuver involves a series of high-torque gymnastic activities
Next up was â€œDaddy Long Legs,â€ a robot with motorized wheels attached to extended legs. It was built by Caleb, Sydney, and Zach. Caleb, the driver, slowly completed the run, also skipping the very difficult 45Â° incline. On the camera-only trial, the robot was not able to place the payload in the designated area.
Anaconda brings its bulk to bear on a one-kilogram block of wood
This monster robot leaps 100 mm platforms with a single bound!
Next was â€œAnacondaâ€, built by Sam P., Isaiah, and Pedro. Itâ€™s most notable feature? The robotâ€™s tracks could rotate all the way around to point in the opposite direction. Sam P. took the wheel, and on his first run, he only skipped the smaller gate. On the camera-only run, he made it through the same obstacles without any issues.
James steers the Iron Horse through both gates and up onto the 100 mm platform
Finally, the “Iron Horseâ€ entered. This robot was built by Sam K., James, Joshua, and Kaitlyn. The design was simple yet effective. However, the extra mechanism they had added to their robot at the last minute broke! It was designed to help them get up onto the two platforms. Fortunately, there was enough power available for it to slowly assist with the obstacle it was built for.
Charging over the gravel pit with a huge ground clearance
Shortly after, that extra mechanism fell off and so did the payload. In a lengthy and complicated series of maneuvers, James used the one-kilogram block to push the payload over into the designated area.
End of the road: the Iron Horse capsizes while trying to free its jammed package (the small yellow catch was supposed to release and allow the hinged door to fall)
On the camera-only run, the Iron Horse’s payload wouldnâ€™t release. James used the gravel pit to try to get the payload to come loose, but the robot flipped over. He attempted to flip the robot back over, but it tipped over on its side instead. This run was incomplete.
The lesson to be learned for these four groups? Each problem can be solved in many different ways, but some are more effective than others. In every problem you encounter, consider those many solutions and then choose the most effective one.
One of the strengths of our Engineering Academy is the opportunity to assign older students to act as teaching assistants for the younger group. This year, we are privileged to have Josh and Claire, both seniors, working behind the scenes day in and day out. Josh and Claire take care of so many important things, freeing me up (Mr. Meadth) to focus on teaching and assisting students.
Following on from the highly successful robotic arm project, our current robotics challenge is to design and build a search and rescue robot. This idea has been widely explored by many universities and private companies. We are proud to have four separate teams, each developing a unique solution for a robot that can navigate a defined obstacle course and deliver a survival package to a person on the other end. Such a robot might be used in an earthquake scenario.
No more talk from me! Let me simply share some excellent photos taken by Josh (thanks once again!) We’ll send out an update once this project is completed, so stay posted.
Sam and Pedro arrange the motors around a differential gearbox
Zach, Sydney, and Caleb working on some very secret plans!
Sam, Pedro, and Isaiah can’t wait to add tracks to their creation!
Nolan and Alan looking for bugs in the program
Sydney gears up for safety!
Sam compares his custom 3D-printed pentagonal wheels as James looks on
Kaitlyn and Josh hard at work writing lines of code
Davis completes some highly necessary modifications to his team’s tracked robot
Mr. Meadth undertakes repairs to one of Zach’s electric motors
James reattaches the front wheels again
Alan considers his 3D-printed component: a rotating “jack” to tilt their robot up and down
There’s a great deal of discussion right now in educational circles about the positive benefits of failure. You don’t have to look far to find TED talks, psychological reviews, and blog articles on why it’s okay–and even beneficial–to fail. Failure, we read, makes us stronger, fights against complacency, and recommits us to our goals. The warnings are shouted loudly: Parents! Don’t shield your kids from failure! Our own faculty member, Carri Svoboda, shared an article earlier this year about why women in particular might be afraid to fail.
The Foundations of Engineering II class in the Providence Engineering Academy were recently given a new project to wrestle with: design and build a robotic prosthetic arm. Using metal motors and controls for the forearm frame, they then had to 3D print a functional palm, fingers, and thumb. No instructions, and nothing off-the-shelf. Oh, and with one more twist–the entire thing was made double size.
James and Zach prepare the Pink Team’s hand
Isaiah and Kaitlyn working on the finishing touches
So what happens when you give a room full of budding engineers a bunch of robotics parts and computers and a 3D printer? Well, for one, a lot of failure. Dead ends and broken components are commonplace. The line of code that worked yesterday doesn’t work today. The team member that needed to design their part in time just doesn’t. Control wires break. Batteries die. Entropy seems to work harder than its usual self.
And that’s okay!
Davis shows Alan his giant metal forearm; the green boxes down the side are the motors to control the 3D-printed fingers
The teams worked hard for seven weeks. During this time, they also visited PathPoint, a nearby organization dedicated to working with those needing assistive technology–the original inspiration for this robotic limb project. The direct experience with those who daily use technology to overcome their difficulties was very moving.
The whole group visiting PathPoint, non-profit working here in Santa Barbara with those needing assistive technology
When all was completed, the four teams loaded up into the school vans, and headed over to the San Roque campus. Their giant articulated hands waved a cheery hello to cars driving by, fingers flexing and twitching in eerie mimicry.
Pedro shows the Yellow Team’s code to a Lower School student
James checks the workings of his pink articulated fingers
The class presented their designs to the 3rd, 4th, 5th, and 6th Grades across two days. On the first day, failure was the name of the game, as every team experienced the frustration of things going wrong. To name just a few of the dozens of problems:
A control line connecting a motor to a finger broke or came untied.
A stop keeping a finger from bending backward broke away.
An elastic band returning the finger to neutral position broke.
A remote control, necessary for demonstration, would not “pair” with the onboard computer.
Another remote control was left behind in the engineering classroom!
Nolan, chief coding specialist for the White Team
A myriad of challenges–yes! More importantly, how did the students respond?
They switched to manual operation instead of motor-controlled.
They took extra time to talk to their elementary-aged guests about 3D printing and robots.
They used tape and scrap pieces to rebuild a finger stop.
They retied control lines, anchoring them with bolts and washers.
They avoided focusing on the problems, and drew their audience’s attention to what was working.
Our 5th Grade teacher, Mrs. Suleiman, shared her highlight of the experience: “Hearing the students talk about the ‘failures’ that happened as they were designing the hands, and watching them deal with problems that occurred during their demonstration.”
Lower School students take a turn wiggling the giant fingers back and forth with the remote control
The students themselves reflected on this very same idea a few days later:
Pedro: “There will always be failure. Failure is good. You learn from it.”
Zach: “Perhaps it is not our mistakes that are the true failures, but the ways that we handle our mistakes that are.”
Alan: “The point of this isn’t about how many failures we have, but how we deal with them.”
Isaiah: “All this goes to say that every problem has a solution. You just have to be willing to persevere.”
And persevere they did. On the second day of presenting, most of the kinks had been worked out. With smiles on their faces, our 9th and 10th Graders talked at length about their coding and CAD. The elementary students were able to take turns at the controls and wiggle those giant fingers back and forth. What a joy to see older students inspiring the younger ones with warmth and kindness!
Nolan helps our Lower School students operate the arm
Our closing thoughts come from Sydney (9th Grader), who wrote some powerfully encouraging thoughts for all of us:
“I know that even in my academic journey at Providence, I have failed many times… This seems like the world can end, yet once you rise up and decide to learn from those failures, you really do learn the most… Through the project of making a robotic hand, I understand that failing is normal and is bound to happen at some point… I have learned that I need a team or a group who can help me when I fail. I need to give myself grace when I do fail… I am grateful for this experience and the hand that was our outcome, even if it was losing a few nuts and bolts by the end. Great work, team!”