Showing posts with label structures. Show all posts
Showing posts with label structures. Show all posts

Monday, April 5, 2021

Update: Wheelchair Computer Desk Feedback

 Back in February, we posted a blog describing the completion and delivery of our wheelchair computer desk to PathPoint. After a few weeks, we were finally able to get Mr. Meadth and Mr. Gil Addison together with his team to go over the design and get that long-awaited feedback.

Feedback from the end user is critical to the entire design process. For this particular project, the Academy had all sorts of unanswered questions: will the design function as requested? Does the screen angle suit a typical wheelchair user? How convenient is the keyboard position? Is the mechanical motion safe enough for general usage? Would a typical PathPoint resident be able to operate the remote control? What improvements could be made? While we don't currently plan on producing a Mk II, one project often leads into another and we improve our products by understanding their strengths and weaknesses.

Gil Addison (far right) together with his grateful staff

Mr. Meadth (center) joins in for the camera

Gil met Mr. Meadth together with six of the PathPoint staff members and together they went over the particulars of the design. You can watch the entire footage here, and a summary of design points is also included below.


As we draw this project to a close, thank you to PathPoint for being willing to work with us in an ongoing fashion! May our students always be inspired to use their God-given gifts with training and understanding, and we hope that the PathPoint residents are blessed through this simple gift.


Thursday, February 18, 2021

Wheelchair Computer Desk: Delivered!

 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.

You can play with the online CAD model here.

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


Monday, May 11, 2020

Design, Build, Fly!

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 May—stay posted for the culmination of this exciting story!

Saturday, November 2, 2019

Collaboration with the Physical Education Department

(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 “CADing” 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 “box joint” technique (resembling a three-dimensional puzzle, used for strength), the two large boxes were finally completed after lots of hard work from last year’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 “very 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

Friday, May 3, 2019

Field Trip to Peabody Stadium

After many months of trying, the Providence Engineering Academy was finally able to secure a field trip to see... well, a field! Peabody Stadium, an integral part of the sporting complex at Santa Barbara High School for almost 100 years, has been greatly in need of renewal for a range of reasons—regular flooding, surface maintenance, seating capability, ADA compliance—and our engineering students were given a sneak peek at the behind-the-scenes process!

Our own neighborhood! Peabody Stadium (old image) to the
upper left, and Providence School to the lower right

A quick walk across Canon Perdido Street brought the group to the construction trailers, where Mat Gradias from Kruger Bensen Ziemer Architects, Inc. met them and introduced them to some members of the construction and design team. Mat has been involved with the Santa Barbara ACE Mentor Program, which several of our students (Eva, Victor, and Seung) have attended for the past two years.

Mat showed the construction plans, and described to the group some of the challenges facing the team, from sourcing grants to managing city wastewater ducts to preserving the "look and feel" of the local neighborhood. The team's original completion date was April 2019, but is now projected for the middle of August.

Josh, Gabe, Victor, Ben, Todd, Colby, Eva, Alena, Claire, and
Madison facing north; behind is the new southern grandstand

There's a lot of mud and dust right now, but over the next few weeks there'll be seeing bright green artificial turf laid out. Regular flooding issues will be a thing of the past, with clever water management systems in the event of severe rainfall. Seating capacity will be greatly improved, and highly directional lighting and sound seeks to minimize light and noise pollution for the surrounding areas. The state-of-the-art track surface will be the only one of its kind for a hundred miles—a type of high-tech material that is known for producing world records.

The Engineering Academy was very grateful to Mat and the other presenters, and they're already excited to see the finished product!

Saturday, December 1, 2018

Tension + Integrity = Tensegrity

The Providence Engineering Academy seeks every year to put skills to use for the benefit of the community. From designing playground equipment to running science lessons, "we have an obligation to turn our skills outward to the world around us; we learn not for our own sakes" (quoted from the Engineering Academy application).

This year, the Advanced Engineering I students took on a challenge from our very own fitness guru, Scott Mitchell. Mr. Mitchell, who teaches middle school P.E. and runs our outdoor education program, is passionate about his craft. He wants students to understand the human body, in terms of both structure and motion. Mr. Mitchell has long used tensegrity structures as an analogy to help students visualize these principles.

What's a tensegrity structure, you ask? While a formal definition is somewhat elusive, you know it when you see it. Popularized by the architect Buckmister Fuller and his student, sculptor Kenneth Snelson, these structures feature "compression members floating in a sea of tension." Still confused?

Here's an animated GIF from Wikipedia's page:



The engineering class began with some small models, using elastic bands for the tension elements and wooden dowels for the compression struts.

Victor with the most simple of all tensegrity structures: three sticks
not touching
Victor and Todd with a six-member icosahedron
Josh finds a new use for the 12-stick version

As simple as these look, they take a great deal of effort to plan and assemble. But this was not the end goal; our class aimed to build a giant version of the icosahedron, with compression members 8 feet long!

Attempt 1:

A lot of knots tied to create 24 rope members. Attached lag bolts to 20 lb beams. Got it together and realized that everything was way too loose. Too much sag. Took it apart.

Alena carefully loops the non-slip knot over the bolt
Ben gets those bolts secured
Inital success and exuberance, but everything is far too loose

Attempt 2:

All rope connections shortened by 5 inches to tighten things up.  Unfortunate result: humanly impossible to pull together. Mr. Mitchell attempted to complete the final connections under great duress. Failure, bent bolts, and an abandoned attempt.



Attempt 3:

Straightened out bolts. Loosened all rope lengths by 2 inches. Realized that we can do this the easy way, working with the structure and not against it. Beams held in different orientation. Pulled it all together, but some bolts bent again. Much tighter, much easier, good result!

Colby and Todd compare the 8-foot version to the 12-inch!

Attempt 4:

Practice makes perfect! Rechecked all ropes, and found a few that were too long. Replaced all bolts with thicker ones twice as strong in bending. Worked in new orientation and got it together in under 10 minutes! (Compare this video to the last.)


Mr. Meadth tests it out before anyone else--in the name of safety,
of course!

Todd climbs inside once everything is approved

Eva's turn!
In case it's not clear from the pictures and videos alone, it has to be emphasized that none of the wooden beams you see are touching each other. Each of them is "floating in a sea of tension", held in place by the 24 ropes. This is despite the fact that the entire structure weighs about 160 lb (73 kg).

Here's another interesting observation: in the interest of safety, we strapped a force gauge to the ropes, and measured 150 lb of tension. (These ropes are rated up to 300 lb, so no problem!) But when Mr. Meadth climbed up on top, weighing about 155 lb himself, the rope tension only increased to 190 lb. How fascinating that 155 lb of live weight does not increase the rope tensions by that amount.

In fact, three people at one time were able to climb up on the structure (totalling more than 300 lb), but the max load reading never exceeded 250 lb, with no evidence of any structural problems.

It's stable, folks! It beautifully and naturally distributes extra load all around to find equilibrium, much like the human body. Even as it moves, it naturally corrects, distorts, and stabilizes. Watch Todd roll a few feet in the following video.


Needless to say, Mr. Mitchell was delighted with the outcome, and brought his middle school P.E. students over to see, touch, and feel its dynamic responses. He taught them that the wooden beams are analagous to our bones, and the tensioned ropes are like our ligaments and tendons and muscles. Inspired by the work of Anatomy Trains, it's easy to see what happens when our bodies are injured or out of alignment.

Great work, students! Keep on dreaming, designing, calculating, and serving others! Please share this article freely with friends and family.

A good day's work!

Wednesday, September 26, 2018

MS Bridges: Welcome to Mr. Eves!

Joining us this year at Providence is the highly qualified Mr. Matt Eves. A long-time friend of Mr. Meadth, Mr. Eves brings his experiences in engineering and business to the AP Calculus AB class with our seniors, and the Intro to Engineering class with the middle schoolers.

Mr. Eves wasted no time in getting down to one of our famous projects: The Bridge! In teams of two, with a list of required constraints, they set about building the longest possible bridge. This is more than just messing around with LEGO; students were demonstrating that they had learned the underlying structural principles of triangular trusses and bending beams.

Josue and Larry measure their jointed creation

Jeffry, one of the able teacher assistants, helps Paul and Ryken

Elizabeth, Carmen, Nate, and Abigail take a moment to smile!

Taylor and Will understood the need for vertical triangles...
is there anything they were still missing?

Tess and Bryce carefully counting the pieces they used

Jonny, another of our teacher assistants, helping Hunter and Reggie

(By the way, if you're wondering about the teacher assistants: Jonny, Jeffry, Emma, and Ruby are all acting in this capacity this semester. Having taken this class once already, they are now bringing their learning to another level by helping the other students. There is no better way to learn than by teaching! They have also been taking time out with Mr. Meadth during class to learn CAD tools, with some of their creations being 3D printed.)

Upon completion, the seven teams laid wooden tracks across their bridges and put them to the test. All teams performed incredibly well, with almost no flexing evident. The following video shows the tests--in each one, what elements of design do you see that are contributing to the bridge's strength?


A great start to the year! Next step: learning about gears and torque. Students will combine these lessons with their knowledge of structural strength to build a special machine... can you guess what it is? All this, so we can learn to build a robot that moves properly and is mechanically strong.

Browse around and check out some of our other recent posts. Feel free to email Mr. Meadth or Mr. Eves for any questions about the Providence engineering programs, and share this post freely with family and friends!

Friday, June 29, 2018

Summer Camp 2018

It was such a roaring success the first time that we just had to do it all over again! The second annual Providence Engineering Summer Camp finished today, and the brightly lit robot city took wings with our special theme: SPACE. We all know it's the final frontier, and our fifteen campers interpreted this idea in a multitude of ways. Alien invasion... meteorite shower... rocket launch... solar system buildings... 3D printed rockets and planets... so much fun!

Todd helps his team with some simple geometric designs

High school engineering students Joshua, Todd, Alena, and Sam led the charge each day teams of devoted campers from Providence and the broader community. We also had a good deal of help from Isabela! These excellent engineers taught the campers how to build electronic circuits, program robots, 3D print fantastic creations, and design out-of-this-world architecture. Illuminated buildings towered high above the cityscape as tiny robots darted to and fro. Electrified copper rails ran this way and that carrying power to critical components, with printed sculptures dotting the landscape.

Success! A single 3 V coin battery powers nine blue LEDs...
or is it only eight?

There was no messing around, either—these elementary students learned their stuff! You can ask them what "LED" stands for, and what a "forever loop" might be used for. They know how to build a working switch out of paper and copper foil, and some of them even used their movie-making skills to record short action videos!

The Robot City landscape continues to become
increasingly illuminated

As the days went by, the creations became increasingly complex. First was the skyscraper that was literally taller than Mr. Meadth. Then came the red/orange/green traffic light by the illuminated airstrip. 3D printed costumes were designed (by the campers, of course) for the tiny Ozobots in the shape of cars, rockets, and trains. And—of course—there was the obligatory fiesta of robot dance parties, all happening in perfect synchronization.

A delightful blue flower stands bold and tall

The end of each day came all too quickly. With lots to take home, we hope these happy campers will continue to code, invent architecture, and design circuits all summer long! Enjoy the rest of the photos, and we hope to have as many of you as possible back next year!

The 3D CAD model (computer aided design), becomes—by magic!—
a brightly lit reality

A tall rocket stands beside a crashed alien spacecraft

Our campers working hard to create all manner of new buildings

The tallest skyscraper in the room, complete with embedded
meteorites and emergency beacons

The Copper Rocket throws an eerie light out onto the empty streets

The giant completed city!