Week 15: Preparing Presentation #3

This week the first set of teams presented to us their sub-groups progress. We are preparing our final presentation in the meantime trying to figure out what force the linear actuator will experience when the boogies accelerate at our max assumed value. Also, new FEA in the linkage system reveals that the lowest safety factor is in the horizontal links shown below in figure 1 with a safety factor of 1.69.

Figure 1. Horizontal links and the stress with safety factor of 1.69

Week 13: Evaluating our new prototype

Our new prototype on Solidworks requires us to perform new FEA and to find the force that the linear actuator will have to exert on the worst case scenario. However, our team suggested we research more into the active components needed to make this approach work first. I needed to do personal research to report back for a discussion with my group members on how to power and control the linear actuator. I found that as an option to control the linear actuator we will need a gyroscope, Arduino, motor driver, and a battery with a battery charger and possible an accelerometer. Fortunately, Dr. Furman had a motor driver that he can let us use for our project, which will allow us to operate the linear actuator from an external power source such as the battery.   

Week 12: New CAD Model

The new CAD model of the suspension unit makes the vertical distance reduce by 6 inches, which is good for practical applications of the suspension unit. I worked with Colin and Joshua in helping direct some of the decisions of the form and research for actual parts that we can buy from McMaster website so that the construction on CAD can be realistic when it comes to building the physical prototype. Below is the new CAD model of our new design as seen in figure 1.

Figure1. Vertical dampening unit is the center link like in the old design

The linear actuator is in place in a position where we are able to achieve a range of 19 degrees in inclination and 24 degrees in declination, which is acceptable for our target goal of at least a 17-degree range from the horizontal. 

Week 11: New iteration on the CAD Model

One of the comments that we received from our presentation number 2, is that the vertical length of the suspension unit might me too large. Which is because of the frame is on top of the vertical dampening unit when it does not have to be necessarily like this. My team and I realized that it is true as seen below in figure 1.

Figure 1. Frame on top of the Vertical Dampening unit

My group and I then went back to the drawing board to come up with a different form that will still encompass the same function. After, long thinking sessions, I came up with the idea to make the vertical dampening unit part of the center link in the frame. To do this, we would have to add some attachment points that could be welded on and make the frame double sided on each side of the vertical dampening unit. This will essentially make the total vertical length of the suspension the length of the vertical dampening unit, which should reduce it by 6 inches. 

We will continue with this new design concept on CAD

 

Week 10: Presentation 2

This week we gave our presentation number 2 to the Spartan Superway Team on our progress. We showcased our rapid prototype and received feedback on our design. Dr. Furman recommended looking into air dashpots and with an electronic orifice. My group and I need to finalize our design so that we can begin further analysis. A link to our slides is below
Presentation 2

Week 9: Preparing of Presentation 2

This week we had the 1/12th presentations that updated us on their progress. After, I started on setting up the presentation template on google slides to get a start on our presentation. I also added the rubric within the comments of the slides so that we can hit all the points.

I got the group to use google hangouts so that we can communicate over the mic as we work on the slides online. This really helped speed up the collaboration and will be something we will start to use. Furthermore, we came to an agreement that an active approach to our design with our original frame design will be a good balance of functionality.

Week 8: Further Evaluation on Design

This week the group and I discussed how we might be able to reduce the pitch swinging due to the longitudinal acceleration. It was found from the previous calculation that 14.3 degrees of angular deflection to be of significance for passenger discomfort. The group and I had some trouble of figuring out possible solutions within the scope of a passive approach.

I brought up that the reason we are having a difficulty with coming up with a final design that would stop or reduce pitch swinging is because we have limited our designs to passive only. The group and I discussed that a complete revision of the design may be needed. As we were discussing, AJ and the summer half-scale team joined our discussion and mentioned that linear actuator can be used to control the pitch swinging.

So our group then focused our attention on using a linear actuator in the frame of our original design to have control. The linear actuator can be used statically (off) for longitudinal acceleration and used dynamically (on) in cohesion with the gravity effects to pitch-level the pod-car while traversing on the inclines.

Week 7: Rapid Prototyping Issues

This week we had a seminar by Dr. Du about the final report guidelines for one hour. Shortly after we headed back to our class and the group and I discussed what problems arose from the rapid prototype.

I mentioned we should find out how much pitch swinging we should expect to encounter in the half scale suspension to find out if it is even severe for passenger discomfort. I remember there was a similar problem in our dynamic textbook that would allow us to calculate what the maximum angle would be, given a longitudinal acceleration.

It is found that the maximum deflection is not a function of the distance L or mass of the hanging weight, but rather of the longitudinal acceleration and gravity relationship. Given a longitudinal acceleration of 2.5 m/s^2, the maximum angle of through which the pendulum swings is 14.3 degrees, which is of significant value for passenger discomfort.

Week 6: Rapid Prototyping for Concept Design

Half-Scale Suspension Team
Saturday, September 30, 2017

Today my group and I met at my home garage from 12-5pm to work on rapid prototyping our concept design for the purpose of evaluating the feasibility. Using the sketch of the design, we imitated the linkage with popsicle sticks, fasteners for the pivots, closet bearings used as sliders to replicate the rail bogies, and lastly, a wire used to replicate an uneven rail. I set up the workstation in my home garage and prepped the tools we would need. Tools: Drill press, drill bits, thin circular file, table disk sander, and wire clippers. We then began construction, as can be seen, the progress in the figures below.

Figure1: Colin using the drill press for the pivot holes on links

Figure 2: Linkage concept, yellow will be the hanging link in connection with the pod-car.

Figure 3: Completed prototype one with demonstrated leveled hanging weight (pod-car) on inclined rail

Figure 4: Rapid prototype rail system for demonstrating working principle of half-scale suspension for pod-car traversing inclined rail

Below are links to download and/or view the videos of our concept design in action as in Figure 4.

Video 1: Demonstrating working principle for half scale suspension

Video 2: Demonstrating half scale suspension of pod car while traversing inclined rail

We have confirmed the passive suspension for leveling the pod-car while transversing inclines will work and confirmed our concern that there will be swinging needed to be dampened. Further prototyping will be planned.

Week 5: On Going presentations

This week, sub-teams gave presentations on their project goals with specifications and a list of problems they may encounter throughout the semester. The full-scale teams and our half-scale suspension team gave presentations in which we were able to give and accept helpful advice or comments. Seeing the presentation slides and hearing what the Dr. Furman and Ron Swenson like about certain slides is good to take note on so that we can improve our presentations in the future. For example, having a zoomed in screenshot of the Gantt chart really helps the viewers understand the information. I will make sure that improvements like this are made in the future presentations.

Week 4: Drafting Designs

Half Scale Suspension Team 2017-2018

I came up with these concept designs revolving on being a fully passive design. The reason is because a passive design is a system that directly uses natural energy (such as sunlight, wind, temperature differences or gravity) to achieve a result without electricity or fuel. Whereas an active design is a system that uses or produces electricity.  

Furthermore, a passive design tends to have zero operational costs and are often valued for their simplicity and aesthetic appeal. On the other hand, an active system although they are valued for their accuracy and functionality they tend to be regularly maintained and replaced. They may also have a higher operational cost and environmental impact. 

Below are my two concept designs with their pros and cons. What the group examined carefully among the drafted designs is if they solve these basic problems:

1.              The leveling of the pod car

2.              The associated swinging that will arise with accelerations and decelerations of the pod car.

3.              The unleveling of the pod car caused by the uneven distribution of weight of the people in the cabin.

Concept design 1 is chosen for the simplicity and flexibility that it seems to allow for adding on what might be needed to take care of problem 2. and 3.  What’s needed is further analysis so that rapid prototyping can begin.

Concept design 1

Pro: 1. Self leveling by gravity 

Con: 2. Needs closer inspection of associated swinging 3. unleveling of the pod car due to uneven distribution of weight of people.

Concept design 2

Pro: 1. Self leveling by gravity and 2. possible associated swinging due to accelerations and decelerations of the pod car taken care of. 

Con: 3. unleveling of pod due to uneven distribution of weight of people. Also the redesign of the pod car itself and more materials that may be needed to created such a support. Size of such a design.

Week 3: Concept Designing

This week, we prepared the Lightning Talk Presentation for the Spartan Superway team to give feedback on our project description, specifications, and most importantly our end goals. After looking into the previous Half-Scale suspension team final report on what where their specifications and end goals we decided to stick for on meeting one in particular specification that they did not achieve all the way. The main specification is to have the pod car remain level with respect to gravity while transversing on inclines and declines of 17 degrees.

After our Lighting Presentations my team and I got the chance to meet with the half-scale team from the summer. They explained to use that they worked on getting the bogies to work together and gave suggestions on what they believe would be the best option. For example they said to look into bell cranks for a combination of active and passive suspension system. Our team will come up with some design iterations for next week and get some input from Dr. Furman and Eric Hagstrom.

Week 2: Group forming and Task

On week two we were assigned to our designated sub-project teams for this years Spartan Superway work. The Team I am in is the Half-Scale Suspension team with my group members Joshua Moreno and Colin Wong. One of the primary objectives for our group as discussed with Dr. Furman and Eric Hagstrom is to create some kind of leveling system for the pod cars that will enable a comfortable ride. Currently the pod car will ascend or descend with the same slope as the rails which means the passengers will experience something similar to a roller coaster ascending and that needs to be fixed with a passive or active suspension system. We hope that our design will be able to solve this problem as it is our primary objective. Things to consider as we set up our Lighting Talk presentation is the specifications we need to address for our objective to be fulfilled.  I have started browsing the archives of past work to understand what worked and what didn't work for the previous academic groups that where in the Half-Scale Suspension team.

Week 1: Introduction

Salvador Hernandez

Email: salvadorthernandez@gmail.com

Introduction
I like making short term academic goals and checking them off as I go so that I can make new ones, each one bringing me closer to my career goals. As I advance ever so closer towards my Bachelor of Science in Mechanical Engineering (Graduating May 2018), my classes are becoming increasingly challenging, yet more captivating in the material. Attending San Jose State University is such a blessing because of the knowledge that professors and peers share with one another. I always aim to learn something new every day and pursue what I want by communicating well with others. Since people will spend almost three-fourths of their life in the professional world it makes logical sense to do something that will enhance your life fruitfulness. My career goal is not just about making progress to get ahead day to day, but also do learn new things and accumulate new experiences because it adds to richness in thought and knowledge. My ideal career is one in which I can use my engineering profession to contribute to innovation that will help society flourish in an efficient and eco-friendly way. As an analogy, I had an amazing opportunity working for Play-Well TEKnologies for over a year as an Engineering Lego Instructor leading dozens of courses myself while inspiring young innovators to work together and tackle exciting objectives. It has helped me prepare for my future plans by solidifying my desire to want to give back to society. I want to continue that gratification I saw in those young innovators when they created something working together. This is why I want to work on automated transit networks and SPARTAN SUPERWAY offers great opportunity.

A Little Background
I believe that the most special attribute that sets me apart from everyone else is the strong drive I have to always want to create or implement something better than there already is. This drive I have is a result from the curiosity I have developed ever since I was a young boy playing with the iconic Lego pieces. My dad, a US Army Soldier Veteran who specialized as an Army Vehicle Mechanic, is my role model because he has an aptitude of figuring out what’s causing the problem to something simply by being patient enough to learn how it needs to work and applying a solution himself. This attribute has developed in me naturally, especially after seeing how he partook in remodeling our house from a one story house to a two story house. Tearing down the old house and seeing how to build a better, bigger house really captivated me in terms of the hard work and design considerations that went into the build. The construction had left a surplus of materials left over and my dad supported me in building my own tiny home in the backyard. Needless to say, I was eight and I had built a tiny home the size of a small bedroom with a window, water proof roofing, insulation, and electricity using a few tools. I learned so much on that build from basic geometry to structural support to safely operating power tools. I have always thought of myself as an inventor even though I was really experimenting with mechanisms that have already been built, but for me its more about learning as much I can because it is a joy to me and that is my advantage over others. For example, both in middle school and high school I broke science records by making my self-powered mechanical car surpass the 2-meter distance goal by a staggering 24 meters over, which I got academically awarded for; and by making a 20-gram balsa wood bridge capable of holding the target weight of 100 lbs., which mine withheld a limited 1165 lbs. because the school ran out of weights., respectively. Thinking intuitively is something I encompass because it pushes me to design, develop, build, and test mechanically the creative ideas I think of. I like to believe that I was molded by the engineering aptitude as I grew up. Even till this day, I have loved every struggle for what I have learned, especially team working with peers in the field of engineering.