Gondola Pod Stabilization

We were tasked by Holmes Solutions to develop a proof of concept of a modular stabilization device for a gondola pod. This device will make make a more comfortable ride for passengers by reducing swingout and acceleration due to wind forces.

The Zippies

Becca

Mechanical Engineer

Becca is a senior mechanical engineering student graduating December 2021. Using her knowledge of testing methods, she focused on data acquisition and data analysis as well as machining for the prototype.

Ian

Mechanical Engineer

Ian is a graduating senior from Boise, Idaho. He used his practical knowledge of sheet metal and manufacturing processes to lead the prototype design and testing portions of the project.

Kirk

Manufacturing Engineer

                                            Kirk is a 4th year Manufacturing engineering major graduating in December of 2021. He plans to return to CP to finish a masters degree, and use his management and leadership skills in an  entrepreneurial career after that. 

Lane

industrial engineer

Lane is graduating this quarter and is a future Manufacturing Engineer at Tempo Communications. Lane worked on the scheduling, project managing and  manufacturing of the project. 

 

Patrick

electrical engineer

Patrick is a 4th Electrical Engineering major graduating this quarter. He plans to attend graduate school to study renewable energy systems and use that knowledge to assist in the creation of a sustainable future.

Acknowledgements

We would like to recognize and thank our sponsor Holmes, our Advisors Karla, Jim, and Vlad, and the engineering professors who guided us during our project. We couldn’t have done it without them.

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Project Overview

Customer Requirements

As a team, we were tasked with devising and creating a system of some kind that would dampen the unwanted motion for the patented switchback system designed by Holmes solutions. They needed something to fit into their work envelope, something inexpensive, and something that would achieve the goal of motion control. 

Swing Allowances

  • Stabilize the roll angle of the pod to ensure a smooth and enjoyable ride
  • Stabilization system cannot impact the functionality of the SWITCHBACK system
  • Max lateral acceleration of the Pod cannot exceed 0.15g
  • Max Swing out angle of pod cannot exceed 10° ± 5° tolerance

Conclusion

After running the tests, we found substantial differences in how the gyroscope dampened the swing. The first graph shows the effect of the gyro when in the upper mount position. When the gyro is on, the pod stabilizes much faster. The graph below that shows how the two mounting locations differ in effectiveness.

With our swing test and impulse tests, we were able to determine if our gyroscope meet the design objectives from Holmes  and we would be able to give them the best recommendation from our results.

Final Design

For the weight and scale of our pod we picked a gyroscope from Kenyon Labs. The gyroscope was gimbled to allow for precession, which is how the gyroscope provides a counter torque.

The pod’s body was constructed out of sheet metal. A wooden dowel and several 1.25 lbs. weights was used to increase the Pod’s weight to emulate the extra weight from passenger and equipment. The gyroscope itself is mounted with two angle brackets that can be flipped vertically depending on the desired mounting location.

This project is sponsored by Holmes Solutions.

Project Background

The SWITCHBACK system developed by Holmes Solutions started as a new trolley for ziplines. Traditionally, ziplines can only travel in a straight line and must stop and switch cables to change directions. The SWITCHBACK system can seamlessly transition from cables to rails, allowing for turning without stopping. 

Note: Above is the patented SWITCHBACK motor, this motor allows for the special transition between cable and rail. 

By adding a motor to the system, it can be used in a passenger gondola system while keeping the ability to turn easily. This system needs to provide a comfortable, relaxing ride, hence the need for a stabilization system.

Conceptual Design

We settled on gyroscopic stabilization for our design due to how effective it seemed to be in applications like cameras and boats. This gyroscope would be mounted below the pod and provide a counter torque to any external forces. For the sake of prototyping,  we decided to build a scaled down model of the pod.

Initial Prototype Concept

  1. 1) Cable mount and pivot point for system. This was later changed to limit the pod’s yaw and pitch rotation.
  2. 2) The front and back faces of the pod were left open to allow for loading/unloading of weights.
  3. 3) Mounting holes for dowels and weights. Due to size of the weights, the number of mounting holes were reduced significantly.
  4. 4) Gyroscope in the lower mounting position. The hole in the floor of the pod allows for mounting brackets to be flipped and the pod mounted inside the pod, closer to the center of mass. Initial testing showed that the gyroscope needed to be gimbled, so this mount changed slightly.

By keeping the density of the pod constant while scaling down the mass, volume, and impact forces, we can make conclusions about the system’s effectiveness at a full-sized scale. By testing the behavior of the system at varying weights and impact forces with and without the gyroscope, we can create dampening curves that show the effectiveness of the gyroscope in stabilizing the pod.

Recommendations

From our results we concluded using a gyroscope for their gondolas would be an effective device to stabilize. Have the gyroscope closer to the middle of the pod would help with the damping of the pod faster.

From scaling our design back to the regular scale of the gondola that Holmes needs to stabilize we recommend a gyroscope that can provide 775 Nm of torque and placed underneath the seats in the middle of the gondola to maximize the effectiveness of the gyroscope.  

Prototype Design

Specifications
Weight: 11lbs (unweighted)
Dimensions : 12″x16″x24″

  • Tools
  • Metal Shear
  • Hand Punch
  • Rivet Gun
  • TiG Welder
  • Drill Press
  • Metal Former
  • Wood Saw
  •  
  • Materials
  • 1/8″ Rivets
  • 28 Gauge 12″x24″ Sheet Metal
  • 1″x3′ Wooden Dowel
  • Carabiner
  •  

Testing Set-Up

The most important part of ensuring a product works is the testing and development stage. The team came up with a unique and inventive way to test our prototype. We devised a system of camera, grid, and motion capture programming to track and plot the motion of the pod as it happened in real time. The data was then ported to excel sheets for further analysis. 

Data captured from this system contained two key metrics, how fast the pod was swinging and how far out the pod would swing. We used to this grid and camera assembly for all of our testing, including all different weights and gyro locations. 

Testing Frame

Along with a pod, we had to design a test-track to emulate the cable condition that Holmes’ endures.

  • The concept for this idea was simple, make a standard yet sturdy frame for our pod so that we can run tests on in. This part of the project really didn’t need to be over-engineered, so its made out of 2″x4″x48″s and 2″x4″x60″s. It was put together with wood screws, and the cable was threaded through to finish. 

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