How to Prepare for Interviews and Tips to Ace Them (Part 2)

The biggest fear that most interviewees have are about how to best answer interview question. I will talk about certain questions I’ve received during interviews. Some of these are also from sites listed in the reference.

1. Why did you pick engineering?

The interviewer is trying to determine your motivation for the job. You should be engaging in your answer. Try to sell engineering as the best career choice. In the past, I would have said that I liked Physics in high school, but that’s not a very great motivation. A better answer would be that engineering makes a large impact in the world we live in. Especially since engineering by definition is to design and improve on technology and systems to better society. You should also tailor this question towards the job, in terms of how you could make the biggest impact through the position in the company.

2. When did you start your job search? Have you been offered any positions?

This goes back to my other blog, Mechanical Engineering Job Searchwhere the job you are searching and applying for should fit your interests and career path. The interviewer can discern whether you’re simply applying to get employed or applying because you want to work in the position. A worker with keen interest is preferred over one who will simply drone on day-to-day. So to answer this question, explain honestly and clearly that you are trying to find the “right job” and what that means to you. Even if you have been offered positions, don’t brag about them, simply answer a yes or no.

3.Tell me about the most challenging engineering project that you have been involved with during the past year.

If you have a portfolio of projects you have worked on (which I strongly recommend), pull it out now. It’s always better to show than talk. Explain the problem solving process using Situation, Task, Action, Result, Transfer (START) technique. For me, one of the most challenging engineering project I had been involved with was developing payload dropper attached to a multi-rotor drone for a solar farm-simulating competition (Situation). There was no precedent system that I could optimize, so I had to design, from scratch, a device to drop off markers onto damaged solar panels (Task). I looked for inspiration on a project-sharing platform, then found a button dispenser to base my marker dropper on. After modelling the marker dropper to fit within the limited space on the drone, I printed and assembled it for testing. As we attempted to test, we encountered unforeseen problems such as wind generated by the drone veering the payload from dropping straight down. With only one day left before competition, we improvised with the available material to make the dropper more stable (Action). Because of this device, we are now able to achieve an important task in the competition (Result). These research, design, prototyping skills will help me transition into any fast-paced workplace and solve engineering problems encountered in the job (Transfer).

4.What new engineering specialty skills have you developed during the past year?

There is no doubt that continual learning is one of the most important aspects in life. Your interviewer wants to know that you’re proactive in acquiring and updating your skills in the ever-changing engineering industry. This question also serves as a great opportunity to show your eagerness to learn on the job. Talk about any skills that are relevant to the position, and how you mastered (or got better at) them. Important skills to Mechanical Engineering include ANSYS, CFD, CAD, and CAM. This semester, I learned how to use Siemens NX 12 software develop CAM programs by assigning appropriate tools, operations and parameters to properly manufacture parts.

There are many more potential interview questions. Take a look at the links provided below. If you have any questions, don’t hesitate to comment them. I look forward to hearing from you! Happy job-hunting everyone.

References:

How to Prepare for Interviews and Tips to Ace Them (Part 1)

As many of you know from Co-op program, interviews can be daunting, but if you prepare sufficiently, then you’ll at least take comfort in knowing you’ve done all you can, the rest is up to fate! From the previous interview experiences I’ve had, I can tell you they were all not completely as horrible as I had imagined. There were many interesting ones as well, stimulating due to the type of brainstorming you get to have. As there are other scenarios that I have not personally experienced, I will be referencing the Interview Toolkit written by UBC Engineering Co-op program.

Interview Appropriate Outfits

First thing you should definitely prepare for is getting an appropriate outfit, especially if you’re on a budget like me. I couldn’t get a complete suit, so I found pieces that fit together from various stores. I got an anti-wrinkle collar shirt and straight-cut black pants from Banana Republic, added a blazer from J Crew, and a pair of black work heels from Aldo. A great store to start off at would be Uniqlo, since they have a variety of very affordable working clothes. Just remember you should get everything neat and clean, meaning ironing out wrinkles and creases and polishing your shoes. These thing should not be left last minute, cause they take time and is crucial to your interviewer’s first impression of you.

Types of interviews

Imagine the scenario of the actual interview, will the interview be one-on-one or will you be placed in a group? If any of the information is unclear, it’s highly suggested that you contact the interviewer or the HR personnel responsible for arranging interviews. I’ve had mostly panel interviews, where two or more interviews take turn asking questions, often about different aspects of the company. One interviewer was usually the higher up manager, while the other was my direct supervisor. This is done so that my supervisor had a chance to see how well they’d work with me. I’ve had one group interview, where about 5 other engineering students were interviewed at the same time as me. We sat around a circular conference table and the interviewers started asking questions. We answered questions voluntarily. As to keep the interview shorter, not everyone was forced to answer each question. I used this opportunity to listen to other interviewee’s responses and tweak mine. Sometimes I felt strongly about an answer so I started first. In this format, try to avoid being aggressive or demeaning, rather, be helpful and agreeable, but at the same time lead conversations where you’d like them to go. Other types of interviews include telephone, live video, and taped video. The expectations aren’t all that different between these formats, and I would say treat them as you would an in-person interview.

Online Networking

When you’re searching for information about the interview, try using LinkedIn. You should know your interviewer’s names, if not, once again I suggest you contact the company. By searching them on LinkedIn, you understand their background, be it in human resources or the technical field. HR professionals will tend to ask non-technical questions related to your soft skills, such as communication, teamwork, and ability to overcome obstacles. On the other hand, interviewers who are engineers, or managers with technical backgrounds will ask about your technical abilities, often in the form of a problem for you to solve. On a side note, after you’ve viewed their profile, they will be notified. This shows your initiative and puts your name in their mind even before the interview. They might even click back, checking your profile for more information about you, so this is also serves as an opportunity to stand out. Therefore, ensure your LinkedIn profile is up-to-date. Writing a personal bio and putting up a professional photo are crucial.

That’s it for part 1, but please also check out part 2, where I’ll talk about the questions I’ve received during interviews, how I answered them using the START technique, and other general tips so you’ll be confident about your next interview!

 

 

Mechanical Engineering Job Search

When looking for a job, ask yourself three questions

  • What do I want to work in?
  • Where do I want to work?
  • Which company is most suited to my future career?

Do a simple search on LinkedIn for mechanical engineering jobs and you’ll see the diverse fields in which a mechanical engineer can work, such as product design, manufacturing, HVAC maintenance, piping systems design, etc… Since there are so many different types of jobs, I started evaluating my preferences. There are two fields that I’m really keen on, first is automation services that will enhance my control and system modelling skills. I also want to get more practice with logic programming and instrumentation coding. The second field is power systems regulation and management, particularly in the renewable energy sector, despite it being more related to electrical engineering. I also like to work on CAD/CAM, skills that are mostly related to product design, validation, and development.

Company size, culture and established locations are also very important to me. Jobs available in the United States and Europe intrigue me, but my top locations are Seattle, New York, and Toronto. In terms of company size, I prefer a global company with job openings everywhere in the world. A globalized company will also allow for more internal mobility, in case I want to switch jobs across departments. A dynamic work environment and a motivated and cooperative team are what I look for in company culture. All these contribute to which jobs I apply to.

A couple companies are on my radar. Siemens is a German conglomerate company with heavy emphasis on automation. Some of their notable divisions are industrial automation, energy automation, building technologies, and drive technology. They have major branch offices in Germany, US and China. They have a prominent division called Gamesa Renewable Energy that have provided wind turbines to offshore and onshore wind farms in the UK and Denmark. An exciting recent development that Siemens Canada acquired is designing the power grid for New Brunswick and Nova Scotia, formally called the Smart Grid Atlantic Project. This project aims to analyzes challenges and opportunities involved in integrating renewables and improving the grid’s reliability and efficiency. I hope that by landing a job with Siemens Canada that I can transition to Siemens in US and participate in their engineering training programs. Another company I would be excited to work for is General Electric. GE is along the same lines as Siemens, a global product-focused company, except they started in the States. In terms of innovation, I think Siemens is a bit more sustainability centered.

There are also lots of regional and local companies I could apply to, not to mention the consulting field is another huge area for engineers to work in. I will explore these in the next blog.

Talk to you soon!

 

 

Classes at ETH vs UBC

Portraits of famous scientists and engineers greet you from the west wall of ETH. The stone causeways and massive wood doors instil a sense of magnitude and significance to the university. Their mechanical engineering courses follow suit. Never have I studied so hard for such mediocre grades.

Part of the challenge came from class format. There is a distinct lack of hand-holding in these courses, which is a good thing. Engineering students at ETH learn very early on to take full control of their own schooling, as all course material is available early on in the semester and most tutorials or quizzes are non-mandatory.  Four of my five course grades were entirely dependent on final exam performance. (this seems less common in other engineering departments).

Think that’s nuts? Many of the exams were formatted as a 20-25 minute oral interview, one on one across from a stoic witness and the professor that remembers every nap you took in class. It takes one forgotten concept or wrong answer to drop a letter grade. Questions ramp up in difficulty and any time spent thinking of responses means less time to show A-grade knowledge in the latter material. This explains why I saw students studying full time all summer for the 7-8 courses (some Spring semester exams happen in August). There’s a re-examination option for oral exams but mobility students (you) don’t get that luxury.

Aside from these terrifying details, the course experience is fantastic — if you’re prepared to put in the work. Many professors are current leaders in their fields, showing off new material from the cutting-edge of applied science. Software exercises utilized modern and industry-relevant applications (though I had a couple concepts explained succinctly via FORTRAN code).

FYI, the exchange structure in 2018 included a flat-rate fee from UBC and waived fees at ETH so you could take as many courses as you were eligible for. Use this to your advantage. Many engineers took things like Artificial Intelligence, Machine Learning, and other out of scope topics for the sake of interest. Your exam registration happens later in the semester and you had no obligation to take the exam for these courses (i.e. to get recognition of them on your transcript). This may change down the road so just check these rules before your trip.

Here is the course list that I took with a brief review of each:

151-0361-00 An Introduction to the Finite-Element Method

The introduction lecture was comically-terrifying, as the professor skimmed through each course topic with key mathematical concepts. So much material was packed into the two hour lecture that I honestly thought I was expected to read half the textbook before classes begun. Speaking of which, it took a month of review and Googling to figure out the first 24 pages, which introduced the underlying principles and derivations.

I think this course is so important to modern day mechanical design. While you may not encounter FEM analysis in every job, the concepts you learn through the course can be applied to a variety of complex engineering problems. Computation time is expensive in professional settings, so knowing how to optimize your simulations for both time and accuracy improves your value to any company.

Despite the niche topic, I think this course made the most impact during my time at ETH.

151-0548-00 Manufacturing of Polymer Composites

The professor for this course regularly consults for the big aerospace and automotive companies while acting as head of the composites department. The 400-page textbook he wrote is a litany of relevant information in the analysis and production of various composites. This course felt like the final boss fight for mechanical engineering students, integrating topics from literally every fundamental course I’ve taken at UBC, as well as some material from my previous life science degree (brush up on your organic chemistry folks).

The material is incredibly useful for those getting into high-performance industries but this was also the toughest exam I took at ETH – an open-book, two-hour written monstrosity with 35 pages of questions and background information. I don’t think anyone finished writing it in the time given. However, the textbook is so good that I will be referencing it for all my future carbon projects (looking at you, Formula UBC).

151-0316-00 Methods in the Innovation Process

I took this course to see how design differed in Europe. The creativity components were a welcome change of pace from the theory overload of my other classes. As expected, a number of design methods and concepts carried over from our excellent offerings at UBC. The course was structured as a miniature design project; each team was expected to complete rounds of proposals and prototypes while exercising different methods of decision-making. I learned that ETH doesn’t require a major design course every year in their MECH program, but a number of these smaller project courses exist as options. It certainly seems ETH weighs undergrad towards the mathematics and fundamentals while UBC perhaps leans the other way.

The course instructors are professionals in their respective fields so the networking and coffee breaks are very worthwhile; consider the experience an opportunity to flex your design muscles and work with different engineering backgrounds. It’s a great way to meet local students too, as you spend many hours together during each workshop.

151-0280-00 Advanced Techniques for the Risk Analysis of Technical Systems

A refresher on stochastics, with emphasis on characterizing complex networks like transportation and energy grids. However, the material carries over to any system with multiple, independent parts. This is highly useful material for design and production engineering. I sometimes wish we were provided a stronger stats background at UBC, but I suppose fitting every “nice-to-have” into the program would keep us there forever.

151-0358-00 Structural Optimization

This course is an excellent complement to FEM (and conveniently, taught by the same professor during my stay). While you learn to solve particular load cases in FEM, Optimization teaches you how to automate the design process to find best-fit solutions. You learn enough in this course to write basic optimization scripts for small scale optimization problems (minimum mass design with target stiffness, for example). More importantly, the courses teach you what is going on behind the scenes in ANSYS or Inspire, so that you know exactly which configurations and how to interpret your results.

Engineering Mentoring: Tour of Corvus Energy

As I mentioned in the previous blog, my mentor is a senior engineer at Corvus Energy. This Monday, he showed me and another engineering mentee around their office and factory. Corvus Energy is a company that makes energy storage solutions, with their most novel product being arrays of battery banks for marine applications, from yachts to ferries. Their ingenuity comes from the robustness, reliability and modular ability of their product. Moreover, it has the flexibility meet different demands of various sizes of marine vessels, from small yachts to large ferries like Scandlines M/V Berlin, a Scandinavian fleet that travels between different ports of Denmark, Germany and Sweden. Seeing a Canadian technology emerge and be competitive in the global market was really impressive, especially when you consider the context. Scandinavia contains some of the world’s most sustainable countries that have made strides at implementing sustainable technology. Yet, it’s a Canadian company that has helped them make their ferries hybrid. Following this trend, I’m hoping that Metro Vancouver, with it’s Renewable City Action plan, will become one of Corvus Energy’s strong corporate client and partner down the road.

The tour gave me such an inspiration. The space was very bright, colorful, and full of energy. When I arrived at the office building, I could immediate tell it was an engineering work space. A section of the building was dedicated to testing and product improvement, with prototypes and instrumentation equipment laid out on work benches. What I also loved about the space was the openness. There was no barrier, no cubicle, allowing the engineers to exchange ideas, and to collaborate.

At the factory, my mentor showed us their product assembly line. On the roller table, there were numerous unfinished products, each representing a stage in the assembly process. Not only were the battery units assembled in the factory, they also underwent stringent testing and validation at every stage. A number of quality control gates were especially designed to ensure the final product will have zero defects before they are deconstructed and shipped off to clients. The cool thing about the factory was how it was expanding. Since Corvus Energy is a growing company, it required more assembly and storage space to accommodate new products. My mentor showed us how they had to build a second level in the warehouse and a new assembly line for new generation product.

With this sort of clean and organized work environment, both in the office and the factory, Corvus Energy employees can truly exert their full potential. My mentor also expressed the importance of connecting the office and factory so engineers can work more cohesively with the technicians on the floor. In my future work space, I would like to work not only with the products I design, but more importantly, establish a strong relationship with the people whose decisions I make affect.

If you want to check out Corvus Energy, here’s their website: https://corvusenergy.com. They have internships and Co-op positions available, so don’t be afraid to reach out!

Tune-in next time for more updates.

 

Second steps in Switzerland: Living Expenses, Establishing Routines

Living Expenses

Spend time shopping around for necessities: groceries, toiletries, etc can vary wildly in price from different shops. The quality spectrum seems much broader than in Canada, with organic (“Bio”), import, and many other options. Fortunately, I’ve found that most budget brands still tend to be high quality, often times better than the Canadian equivalent. Local dairy products and in-season produce are all excellent.

If you haven’t developed the habit yet, it’d be a good time to track your expenses and learn where your money goes every month. It’s tough to incorporate into daily routines as a stressed student, but ETH courses seem to happen in 2-3 hour blocks, minimizing time spent commuting to multiple hour-long sessions a week. Set up your own spreadsheet or use software like Mint or YNAB. You’ll be shocked at how quickly those frappes and/or gipfelis add up. I never budgeted during my first degree and by the end of first year I discovered $500 evaporated into bubble tea…

A good metric is to imagine the cost of a trip or experience you really enjoy, whether that’s travel, gastronomy, etc. Travel is absurdly affordable here, so it’s easier to put time into making coffee every morning when you’re saving 0.5 “Transit to Italy” every week.

ETH recommends setting aside 1750 CHF per month as typical cost of living, including rent, bills, etc. If you secure WOKO housing, this figure may be quite high. Here are a few ranges I saw during my exchange for monthly expenses:

    • 450 – 600 CHF rent
    • 65 – 100 CHF Swiss healthcare
    • 70 – 90 CHF monthly transit pass
    • 10 – 40 CHF phone plan
    • 150 – 400 CHF food (yikes)
    • 100 – 500 CHF leisure
    • 100 – 300 CHF irregular expenses (new clothes, one-time fees, whatever)

If you figure out batch-cooking at home, cycle or walk most places to save the monthly transit pass, and plan your weekend trips in advance (Check out SBB Supersaver tickets) you can get away with 1000 to 1200 CHF per month in total expenses. Most students seemed to be in the range of 1200 to 1500.

Fun fact: the last survey indicated a median monthly salary of 7500 CHF per month for technical positions in Switzerland.

With regards to leisure and travel, that 100-500 range depends a lot on transportation options. Switzerland’s domestic train system offers a bunch of Student perks to cut their relatively-high ticket prices. I took advantage of two key discounts during local travel while other students added a third:

  1. Halbtax (Half-fare) Subscription
  2. Supersaver tickets
  3. Gleissieben (Gate Seven) Subscription

1 and 3 are both upfront payments for 12 months (with a possible 6 month refund point to get some money back I believe). The halbtax offers half price 2nd-class fares on almost every train any time of the day. Gleisseiben provides free travel to students (<25 years old) between 19:00 and 5:00. Almost everyone bought the halbtax, but do the math to see if Gleissieben would be worth it. I found most students traveled in groups and if only a few people had gleissieben they were usually outvoted regarding travel times.

Supersaver tickets are discounts for specific trains at specific times that you can find listed on the sbb website when you’re browsing potential trips. While normal train tickets allow travel on any line heading in your direction within a specific period of time, the Supersaver tickets limit you to one particular departure. These are nonrefundable so make sure you’re not late if you take advantage of this. Supersaver can be stacked with Halbtax which can be super useful, especially as they tend to be off-hour departure times which students can usually take advantage of.

I know it sounds complicated at first. It stays complicated once you get used to it.

Establishing Routines

After sorting out your favourite spots, it’s important to find a groove early-on. Jet lag, new people, weird class schedules, and the plethora of student activities/events will be super distracting. It was March by the time I had cracked open my course PDFs and printed them like all the local students had already done (P.S. your ETH card comes preloaded with more than enough print credit for you to print these all out on campus!). This groove can (and should) include adventuring time. Wander the dense city streets or hundreds of nature trails. Take the train to an unfamiliar place. It’s easy to get lost in Switzerland, but you’re always close to a railway, bus, or restaurant and they’ve never even heard of ghettos.

While it might feel like ETH classes provide a lot more free time than anticipated, fit some studying/reading of the lecture material in every week. It’s tough to do if you have classes with no weekly assignments and new travel propositions every weekend. Find an hour or two every day if possible, as the material stacks up very quickly. For example, my Finite Element class covered a month of material by North American standards within the first two lectures. Oral exam preparation is a different beast to written tests; more on this in later posts.

Set up calendar reminders or e-banking payments for monthly expenses. Many students forget about rent, phone bills, etc as they get used to their new bank accounts. New habits might include transferring funds from Canada to Switzerland, or converting Euros before trips abroad. You may have to make payments in person at the local post office so account for processing times. Late fees aren’t cheap here.

More about courses and examinations in the next post!

First Steps 2 – Electric Boogaloo: Student Visa, Residence Permit, Health Insurance, Banking

First Steps 2 – Electric Boogaloo: Visa, Residence Permit, Health Insurance, Bank Account

Part of the initial Mobility application to ETH includes the processing of a Visa Authorization form, which the Swiss Consulate needs to issue your official student visa. However, the fee for this authorization form wasn’t required until you get to ETH Zurich. It’s payable at the school, so don’t forget to pay this; supposedly many students do.

Residence Permit is listed in the ETH Zurich pre-trip documents package as obtainable after a certain number of weeks in Zurich. Try to beat the rush by getting your student documents as soon as possible from ETH. Importantly, the city will want your Matriculation paperwork that comes in this document package. Then, find your local city office and they can process the permit as long as you have everything exactly as described in the permit requirements list. Passport sized photos are used for a number of ID cards during your stay (off the top of my head, residence permit, transit pass, Erasmus Student Network card, International Driver’s License) and you can get them done at many automated photo booths around the city. Don’t be afraid to get the strip of 4 or 5 photos, as you’ll definitely make use of them.

Fun fact: In 2018, Zurich still had two operational automated dark-room photo booths that performed the same functions electromechanically as the modern digital ones — super cool to operate as aspiring mechanical engineers. I met the gentleman responsible for refilling the exposing chemicals and had a lovely chat. Try to find them on Google Maps if they’re still around!

Non-EU students pay a higher fee for the Residence Permit so make sure to bring a couple hundred Francs or set up a local bank account quickly.

Speaking of bank accounts, make sure to open one as soon as possible (if you require it). Some banks have been known to deny students if they are staying for less than 3-4 months. Single semester exchanges just barely satisfy this requirement! You’ll end up saving a bit of money going this route as the accounts are typically free for students and you avoid the fees that local Canadian credit and debit cards typically charge for usage in foreign currencies. Reward programs exist too that netted me about 100 francs by the end of my exchange. In addition, reputable, online services exist to transfer currencies between your CAD and Swiss accounts without having to go to pricy local currency places. Some of these services even have bright green international debit cards you can use to get cash from nearly any European ATM. Look for these 😉

German Classes

UZH, a sister university to ETH, offers an intensive German class that occurs before the start of semester and has limited seating. The language center or “Sprachenzentrum” will post the start and registration dates fairly early. I’d recommend doing the intensive course if you can; not only is it better timing as you’ll have a beginner’s grasp of German before school starts, but you’ll remember more of it since you’re immersed full time for two weeks. Semester courses only happen once or twice a week, with teachers reporting most students forget more of the beginning material by the middle or end of the semester.

Note: This will seem obvious to some, but dates are listed as DD.MM.YYYY which may be different than you’re used to; double check registration time zones and dates! People were still booking incorrect train tickets and accommodations halfway through semester because of these minor differences.

The intensive German class is also a great way to meet people outside of whichever residence you’re in. The class is typically other exchange students and you spend every day with them, so you’ll have plenty of opportunity to connect with people for alpine trips and other adventures before the semester really gets going. The teachers included a surprise session on tips and tricks around Switzerland. There were quite a few useful reminders in there, including various student discounts to take advantage of outside campus, travel discounts, and services such as bike and car shares that I wouldn’t have known about otherwise. My class ended with a day trip to the local zoo and final “apero” with the teachers. Apero is another great opportunity to meet local and international students alike; don’t be afraid to exchange contact info after a short exchange. Sprachenzentrum supports all ETH and UZH programs so you may not get another chance!

 

Engineering Mentoring Program

This year I registered for the mentoring program for undergraduate engineering students. This gave me an opportunity to connect with a professional engineer who has decades of experience in the energy industry that I am interested working in. So far we’ve chatted about the level of flexibility of my Mechanical Engineering degree. Although you won’t be able to attain an electrical or civil engineering job, there are still many positions that does not specify the type of engineering. This is often the case in mid to upper management levels. However, I can’t expect to land a job in management without much experience. The truth is, even entry-level job postings may have 3-5 years work experience as a requirement. I have only 16 months of co-op work experience, therefore it is challenging to apply. However, I feel confident that after being accepted into an entry position, I can work up the experience to eventually achieve management level. I am further assured of this by my mentor’s own experience of going from a technical-heavy job to the management position he has now. His experience has also showed me that it’s never too late to give yourself more education. After getting years of technical experience, I am looking to open up my options by getting a project management degree.

He has also offered help on reviewing resumes and cover letters that I am sending out. A few job positions that I have my eye on are with the Vancouver Airport Authority and Metro Vancouver. I am looking outside of BC. Ideally, I would like to work in Europe but I would also love to explore other places that challenge me. Having a mentor to support my job search is a fantastic resource. It has improved my confidence to apply to more challenging job positions.

We’re currently schedule to visit my mentor’s company this week. I am truly intrigued to find out more about what he does for work and what the environment is like.

This is a short blog, but as I continue my job search, I’ll update you with information about major companies hiring Mechanical Engineers, the jobs available, and tips for applying and getting through interviews!

If you want to check out the mentoring program for yourself, here’s the link: https://engineering.ubc.ca/research-industry/mentoring-program.

Daisy Drive Capstone Project

Fig. 1 – Solar-powered tricycle, Daisy, at Burning Man

Introduction

The Capstone project is usually done during the final year of your engineering degree. Each department get projects provided by companies related to their areas of expertise. For UBC Mechanical Engineering, the projects range from fluid dynamic pipe flow testing, biomedical knee braces, to rovers that fix wind turbine blades.

All the potential projects are presented to you in the first week of September. Then you’re allowed to rank your choice of top five projects. I was matched with my second choice, eatART Daisy Drive project, along with three other Mechanical Engineering students. The eatART (energy awareness through art) foundation is a not-for-profit foundation composed of volunteers from the STEM and art fields. Our client is the Co-Executive Director who is also a mechanical engineer and UBC alumni. Our project is to optimize the design of the electrical belt drive of the largest solar-powered tricycle in the world, Daisy.

Built approximately 20 years ago by inventor Bob Schneeveis, Daisy traveled to Burning Man, an annual festival celebrating community and art and was used to drive passengers around using purely solar power. At its maximum capacity, Daisy can carry four adults in its carriage plus a driver in the front. It is steered by a hand crank and speed-controlled by a foot pedal throttle. Due to its size and weight, Daisy has only been able to travel on flat ground, such as the desert where Burning Man takes place. Now that Daisy is in the possession of the eatART foundation in Vancouver, our aim is to improve Daisy’s climbable incline so that it fits in with the hilly terrain of Vancouver.

First Term Steps to Capstone

1. Define value for stakeholders. Establish scope of your project.

Since our team is working for a not-for-profit organization, our project’s value is in the social-good generated rather than monetary value. With an optimized drive system, Daisy can be used in Whistler village, where roads are at a slight incline. Allowing Daisy to carry visitors in Whistler allows the eatART foundation actively showcases the accessibility of renewable energy technology such as solar power.

Initially, our client mentioned that the major design issue is in the V-belt that translates the motion of the rotating motor shaft to the three meter tall front wheel. When the V-belt slips from the sheave, this means that despite the motor still turning, the wheel stays stationary. This is particularly dangerous on an inclined road, since the front wheel will start to slip backwards without braking. Even with brakes applied, Daisy remains stuck on the inclined road, and cannot move forwards at all.

Another mechanical design flaw was in the belt tensioning mechanism. This mechanism provides tension in the V belt by pulling the two sheaves apart further. This is currently done by winding up a torsion screw attached to the motor and the front frame. This tensioning system doesn’t seem to be properly designed and may be experiencing induced strains and stresses. By redesigning the tensioning mechanism, we could eliminate these stresses and eccentricity, allowing the sheaves to be correctly positioned relative to each other.

To climb a hill, a certain torque is required. Imagine changing to a smaller gear on your bike while climbing a hill. You slow down significantly, but it becomes easier to pedal. A smaller gear ratio means that speed is traded off for torque. Similarly, the current motor and gear configuration could not provide sufficient torque to climb any incline because the gear ratio was too big.

Limitations also arise from the electrical system, as the batteries only provide 24 volts, the motor controller seemed to be old and out-of-date. The motor’s torque capability sets another limit. Its peak torque (stall-torque) and power could be simply insufficient to move the large tricycle.

To sum up all the aforementioned design flaws, they include:

  • V-belt slippage,
  • belt tensioning device,
  • low gear ratio,
  • and electrical power limit.

2. Investigate the problem. Define functions of your solution.

Since Daisy was quite old, the information on its components were not recorded well. Through testing and investigation, we collected data on the electrical motor, the motor controller, and the drive.

For instance, we tested the efficiency of the motor controller. Running the motor without the V belt attachment, we measured the input current from batteries to the controller, and the output current from controller to motor. Then, the power was calculated from the simple P=IV equation. The ratio of Pin / Pout represents the controller’s efficiency. Since Daisy has a throttle, we ran test trials by varying the power draw from motor, from 17% to 100% of power draw. The controller efficiency we calculated is represented in the graph below.

Fig. 2 – Controller efficiency as power draw from battery increases

Evidently, the controller efficiency was above 60% at all times. More importantly, the controller was operating at 100% efficiency near the max power draw from motor. We concluded that a replacement for the controller was not necessary.

3. Conceptualize different solutions.

After defining the functions required to perform by your solution, create various concepts through simple sketching. Aim for quantity instead of quality. You want as many concepts for each function as you can. These become your concept fragments; they are fitted together into whole concepts through mechanical mounts.

Fig. 3 – Concept sketches; (on left) treads with timing belt; (on right) pedal chain drive

After attaining several whole concepts, you should evaluate them on a impartial basis through winnowing, Pugh chart, and a weighted decision matrix. We evaluate our concepts based on a variety of performance metrics, one of which essential to any project is cost. Even though our team had lots of different concepts involving electrical components, they did not do very well in the cost criterion of the Weighted Decision Matrix. In the end, we ended with two concepts with good potential, the chain drive and added traction on wheels. The two-stage chain drive concept we came up with would eliminate slippage and increase the effective torque translated.

Fig. 4 – Two-stage chain drive concept sketch

As opposed to a single stage chain drive, two stage would allow a much greater gear ratio while staying within the recommended roller chain to sprocket contact.

4. Create a critical functional prototype (CFP).

The critical functional prototype (CFP) is designed around a selected function that’s critical to your solution. This is a great chance to see the physical (not theoretical) feasibility of your concept without investing resources into the whole concept. The CFP also allows you to detect unexpected failure modes, undesirable defects, and incalculable performance issues.

We needed to confirm that a chain drive can sufficiently translate motion from motor to the wheel, so we built a chain drive prototype consistent of a motor, a driving sprocket and a driven sprocket. The gear ratio (# teeth driving / # teeth driven) is 17:73 or approximately 1:4. We also set up the different transverse offset to see the upper limit at which the chain starts to derail, rendering the drive useless.

Fig. 5 – Chain drive critical functional prototype test rig

The motor was running at different speeds with light shocks applied. What we found was that for commercially made sprockets (with special profiled teeth), there was almost no derailment at any transverse offset or motor speed. However, for the water-jetted sprocket, there was almost always derailment. Upon closer inspection, the aluminum plate may also have deformed while in storage, so the sprocket it made was slightly bent, leading to the chain derailing.

5. Reiterate the design

After presenting to the client once more with our CFP experiment results, the chain drive concept was deemed too risky to implement. It would increase the number of mechanical components, and due to lack of slippage, could cause irreparable harm to the motor and electrical components if the drive gets jammed.

The concept we ended up with is increased traction (through additive materials and increase wheel width) and better tensioning of the driving pulley to eliminate V belt slippage.
Through preliminary calculations, we also discovered that the batteries shifted a lot of weight to the rear of the tricycle. On a hill, this would create a lifting effect on the front wheel. By shifting the position of the batteries closer to the front wheel, we could better distribute Daisy’s weight and give it more grip on the road.

We decided, along with the clients, that a prototype wheel should be built to test different traction materials such as truck bed liner, spray-on rubber, and etching notches into the flat bar metal. We will be building a section of the wheel out of steel flat bar, attached to an electric motor at the same torque and the power level as the one on Daisy. Then we can apply the various materials onto the section and run it on a ramp. If the section successfully climbs the ramp, then it proves that the material provides sufficient power. If the section slips, then there is not enough traction. Oppositely, if the section is stuck, then there is too much traction force.

That’s all for now. The design process will resume next semester with fabrication.

If you have any questions, please comment down below. I look forward to chatting with you.

Cheers,

Kirsten

Acing Finals – A Video Guide

Finals can be a stressful time of year.  Now that I’m finishing up my 3rd year of Mechanical Engineering, I’ve personally had my fair share of those panicked last minute cram sessions (and have learned to avoid them at all costs).

If you’re interested in learning about how I personally get through finals nowadays, you’re in luck!  The first ever Mech Ambassadors Vlog covers just that, check it out!

Music: Bensound – Hip Jazz