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Technical presentation.


Chrisxr2

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okay so i have to make a technical presentation as part of a job interview, one of the people is technically minded and one not, i have worked across many industries, offshore, seismic surveying, geotechnical surveying, Royal air force avionics technician, but none of them would make a 20 minute presentation (yes really twenty minutes) without being really dull. I am thinking of maybe trying to do one on the technology of electric unicycles, but is there enough information on them to be technical and informative for twenty minutes??

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All depend on the technicality level that you have/want to reach, but there's informations for years of presentation : brushless motors, gyros and accelerometers, regulation, Li-ons batteries, firmware, ... Ask @electric_vehicle_lover, he works on his project(s) since near 1 year and he's always learning and make us discover things.

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To me, the most fascinating aspect of electric unicycles is the control theory part of it. I would probably start with the underlying problem and what makes it so interesting: the operating condition of an EUC is inherently an unstable one, requiring constant correction in order to not completely collapse (sort of like a jet fighter). The best part? The solution to the propulsion problem is elegantly enough the very same as the solution to maintaining perfect balance. Neat!

Since this is a classic problem in Control Theory (called the Inverted Pendulum problem) -- existing long before the Segway was invented -- there are several clever ways of solving this problem. LQR controllers are the most straightforward, but you might also look into PID (or frequently just PI, as the Derivative part can usually be omitted) and more generally Optimal Control, Nonlinear Control, and the modeling of Dynamic Systems.

Moving on, there are lots to do in terms of optimizing the result (e.g. fast response without needing a beefy CPU), as well as the product itself (lightweight and compact, for instance by using lighter and stronger metals in the rotating mass of the motor and rim of the wheel). Not to mention the batteries; just battery theory itself could easily fill your 20 minutes!

I hope this gave you some food for thought (and some stuff to Google). Best of luck!

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Presentations...you will know in the first minute if you have captured their attention.  Lots of questions so I am going to approach your question from another angle. Who is your audience? Male, female, age range? What is the job you are interviewing for? Are they looking to see how well you communicate with others? Wow...small group..only 2? Chairs around a table setting or do they allow for a power point presentation with a screen? Did they give you a specific format you must follow? Sorry but it helps to know these things before entering the lion's den. Been there, done that!

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Rehab, its one guy in his mid 40s very technically minded and i have met him before, and the company secretary whom i have never met and have no idea of age or anything else except that she is not technically minded. All i have been given is make a 20 minute presentation of a technical nature. the job is for a company that measure what materials are made out of and the the thickness of paint or industrial coatings. I have been given scant information to go on. They have laptop but no projector.

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Right, i am going to do it on electric unicycles, i have messaged electric_vehicle_lover and i have messages invites customer service (Who make my solo wheel) It has to be technical but also keep people entertained, any help people can offer would be great, battery technology, regenerative breaking, how they balance, anything you have that could help in a powerpoint presentation, i have a week.

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On 5 August 2016 at 6:14 PM, Chrisxr2 said:

okay so i have to make a technical presentation as part of a job interview, one of the people is technically minded and one not, i have worked across many industries, offshore, seismic surveying, geotechnical surveying, Royal air force avionics technician, but none of them would make a 20 minute presentation (yes really twenty minutes) without being really dull. I am thinking of maybe trying to do one on the technology of electric unicycles, but is there enough information on them to be technical and informative for twenty minutes??

Go for it, there is plenty of info available and few people are really aware of them yet so it should not be hard to make interesting.

Back in 1995 I had to do a technical presentation (my choice of subject) for a job in Reuters Training. I managed to talk for 20 minutes on how telephone caller display worked as it was brand new back then. I got the job, turned out they were looking for someone who understood communications protocols!

Just make sure you spell 'braking' correctly ;-)

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@Chrisxr2 I am available to answer technical questions.

For a presentation I would try to be positive e show in photos that kids up to older people have fun riding EUCs. Them I would explain the main pieces of technology and historically saying that most of technology comes from Ebikes + hexacopters (IMU sensor). I would finalize talking a bit about the DIY scene, people designing and 3D printing their shells and Chinese companies like MicroWorks that sells every part and even stimulate DIY!! -- we are just starting ;-) :-)

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A few other topics that you can touch upon are the challenges that current EUC designs are encountering such as MOSFET failures due to excessive current and heat dissipation challenges.  Firmware or hardware issues resulting in balancing failures.  Areas of improvement like different material hub motor casings and designs to reduce weight.  Lithium Ion battery versus Lithium Polymer technology challenges including damage, thermal runaway, BMS protection versus rider safety designs,  A little history of self-balancing technology is always interesting for background information

I would engage in discussing the implementation of tilt-back in EUC's, and how that works and how it can fail.  The concept of safe maximum speed while maintaining a reserve excess of speed capability / torque could be discussed while referencing the speed/torque graphs of electric motors as well as load / road condition (wind, slope, tire pressure, surface) influences.  PWM motor control theory would also take several minutes to explain.  If 20 minutes is all you have, you might want to divide it up into a 3 or 4 minute sections and include 5 main topics and try to stay focused rather than dilute things by including too much information.  20 minutes is not a heck of a lot of time!  Renting or bringing in your own projection screen to include some short Vine length videos interspersed between "dry" topics will help keep the non-techies and visual learners more entertained and awake.   Bringing in a working wheel (have you gotten your Solowheel repaired?) for a short demo will surely wow the crowd.  :lol:

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29 minutes ago, Chrisxr2 said:

OK, draft presentation attached, i know its a bit simple but there is not a huge amount of info out there to be honest and i need to have it a bit technical but not too much, any critique or suggested additions appreciated.S

 

unicycle.pptx

You've choosen the wrong DC motor in your presentation - in EUCs brushless motors are used. And these use at least 3 magnets and coils, since the "emerged" from 3 phase machines... (Ewheels use bldc's with someting around 40 magnets/coils)

imho also regenerative breaking is of minor importance (bad efficiency) and bluetooth is just a protocol which has quite nothing to do with ewheels - its just used for some communication...

why don't you present the bases of how an EUC drives/balances ( control mechanism, inverted pendulum, accelertion by leaning forward, tilt back, etc...)? Advantages/disatvandages/problems/state of the development by now...

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Absolutely in agreement with @Chriull, the presentation wasn't what I was expecting. You are being specific where you don't need to/shouldn't (1800W motor, Lithium Ion batteries - I think your Solowheel uses LiFePO4 for example and Bluetooth which isn't at all needed by an EUC) vague where there needs to be detail. 

The key important details of any EUC are the controller and its gyros plus its Brushless DC outrunner type motor which gives the high torque and efficiency needed without the complexity of gearing. start by having a look at this: 

Then follow the links offered here: https://en.m.wikipedia.org/wiki/Self-balancing_unicycle

I know you are trying not to be too technical, but you need at least the basics of what makes it work as your foundation. A few more pictures, and diagrams, animated if at all possible would go a long way to make it "feel" less technical and easier for a layperson to understand.

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3 hours ago, Keith said:

Absolutely in agreement with @Chriull, the presentation wasn't what I was expecting. You are being specific where you don't need to/shouldn't (1800W motor, Lithium Ion batteries - I think your Solowheel uses LiFePO4 for example and Bluetooth which isn't at all needed by an EUC) vague where there needs to be detail. 

The key important details of any EUC are the controller and its gyros plus its Brushless DC outrunner type motor which gives the high torque and efficiency needed without the complexity of gearing. start by having a look at this: 

Then follow the links offered here: https://en.m.wikipedia.org/wiki/Self-balancing_unicycle

I know you are trying not to be too technical, but you need at least the basics of what makes it work as your foundation. A few more pictures, and diagrams, animated if at all possible would go a long way to make it "feel" less technical and easier for a layperson to understand.

Thanks I only have a laptop to present on, no projector is available, so yes I agree with more animations but they have much less wow factor.  (Also 3.3 meg file upload limit on here which is the current file size already) As previously said it needs to be 15 to 20 mins which is an absolute age to carry out a presentation if I start to get in too gyroscope theory it becomes very long and will very quickly indeed lose the non technical person, the Solowheel xtreme does have Bluetooth, it's just an extra slide for padding to be honest.

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2 minutes ago, electric_vehicle_lover said:

IMO, most relevant parts are: motor and the details of brushless and many poles for this specific application; battery pack of cells with same form as Tesla and the BMS board; controller board that runs the motor and balance the EUC using the sensor and doing inverted pendulum logic; mechanical parts.

I completely agree but there is little enough information available  on how the bms controller etc work, and bearing in mind you have to work to the least technical person in the room as you can go up in technicality easily but not come down, i think i may go with my original presentation on seismic, geotechnical and geophysical investigations as i believe going any deeper than i have in my presentation with the exception of changing to how brushless motors work will lose the non technical person and make the whole presentation more dry and boring and less lighthearted.

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There honestly is lots of information at the interesting level, for example just off of the top of my head: the reason accurate 3 axis solid state gyros are so cheaply and readily available is because they were developed for mobile phones and made in their multi-millions, that the technology is the same as used in quadcopters, etc, etc, the development of Segway, extending that onto single wheel vehicles, using the analogy of balancing a broom on your hand to explain what the electronics is achieving. The effect of torque and why top speed is limited due to the decrease in torque with RPM (simple graph will show this clearly)

If I could successfully talk to a mixed audience of Finance Markets professionals on Caller Display protocols for 20 minutes, anything is possible!

However, if you don't have a really good grasp of the technology yourself, I think you risk being easily caught out by questions so you are going to be a lot better off and come across a lot more relaxed by staying within your comfort zone.

What ever subject you choose two bits of general advice:

1)

  • Tell them what you are going to tell them
  • Tell them.
  • Tell them what you told them.

2) Get yourself a captive audience and rehearse it in front of them with a stop watch - my HR professional wife can probably still explain caller display and hasn't quite forgiven me for running through it again the night before the event - in the interval at a Classical Concert!

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@Chrisxr2, sorry, just realised you said there isn't much info on how the BMS works: see this post, there is also a link to a video on the subject in the post I quote. If the images in my post (or my description) is useful to you, you have my permission to use them (they are my own hastily done drawings - not something I 'stole' from somewhere else). They were done in the IOS program Graphics, you are welcome to the source files if you can use them.

 

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