Week 12: Revising design on SolidWorks

This week the team worked on developing our new concept to be incorporated into the half-scale suspension on SolidWorks. Our concept is to have the dampening system link not on the bottom like we originally had (Figure 1) but used as the center link to shorten the overall vertical length of the suspension (Figure 2). 
After creating this CAD Model we got to see what are the limitations of our concept design based on the dimensions of our components and the overall form of the parts. We realized after measuring within Solidworks that we need improvement on getting a greater range of pitch angle because we are currently getting 19 degrees in incline and 24 degrees in decline. Also, further development of a modular design needs to be implemented in our design so that we can manufacture with easy and have the opportunity to reiterate the components without needing to cut away. 
We will continue refining our CAD model and start to perform our analysis with FEA in the following weeks.

Week 11: Finalizing our design

We decided to use the dampening system as an actual link to shorten the vertical length of the suspension. A CAD model is currently being worked on and will hopefully be finished by next week. We also plan on continuing our FEA analysis with ANSYS within the next couple of weeks.

Week 10: Presentation 2

This week we gave a presentation to update our peers on our current work. A link to the presentation is below.

Week 9: Presentation Development

This week the 1/12th group presentations were done. They talked about their progress and we got to see some CAD drawings.

Our team met up and began to make our powerpoint slides to showcase where we stand.

Our design will keep with the concept of the linkage but with the addition of a linear actuator in the frame to have control over the pitch swinging. This means that we have a battery, accelerometer, gyroscope, and an Arduino. The linear actuator will work statically (off ) during the longitudinal accelerations and work dynamically ( on ) in cohesion with gravity to pitch-level the pod car as it traverses in inclines or declines.

We will continue to evaluate our design for further improvement. For instance, how we can make the suspension mechanisms shorted in vertical length to be more compact in size.

Week 8: Design Modifications and Presentation 2

During Week 8, we applied changes to the design of the suspension.

In our original design, there was swinging due to linear acceleration and a lack of vibration damping on the vertical axis.

Figure 1. Original design
Our suspension design therefore needed to be modified to fit the design requirements. The addition of a linear actuator across the links allows for control of the links and a spring-damper system will damp the vibrations. The linear actuator will move in response to the position of the links and the acceleration of the pod car. The spring stiffness and damping coefficient will need to be calculated in the future to build the spring-damper system.

Figure 2. Prime design concept
FEA was also done on a CAD model of our system. Our results indicate that deflection is not a major problem and the minimum factor of safety is good for our purposes.

Figure 3. FEA on spring-damper support
In Week 9, we will refine our design even further and begin assembling a bill of materials.

Week 7: Rapid Prototype issues

Dr. Du taught a 1 hour lecture about the final report guidelines. After, we headed back to Spartan Superway to discuss further action that needed to be taken upon for our project.

The swinging motion from our rapid prototype is the primary issue with our design. The pod car stays leveled as it transverses along the rails, however the entire linkage swings like a pendulum as it experiences acceleration.

We also met up at the library to discuss solutions, revisions, and alternative designs that we might have to consider for our project.

Week 6: Prototyping our design

In Week 6, we began prototyping our design for the half-scale suspension. We had two objectives for this prototype: to determine whether our design auto-levels and to see the severity of swinging.

We built our prototype out of popsicle sticks, pulleys, and nuts and bolts, then guided it along a wire track. We discovered that even at extreme angles, the prototype did indeed auto-level with the influence of gravity only. However, there was significant swinging whenever our prototype came to a stop.

Overall, we feel like we have learned much from this prototype. Next, we will begin the process of finding ways to lessen the swinging. If we do not find an adequate solution, we will explore our backup designs.