Spartan Superway Half Scale Suspension 2017

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. Newest design concept 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.

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...

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.

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.