Current Hardware

RaPOD Wrist:

The RaPOD Wrist was developed in cooperation with The University of Montpillier. The RaPOD wrist completes a 90-90 rotation around two axis with one degree of freedom. The mechanism was optimized to use link angles that were common for ease of manufacturability.

Click Here to see an alternate RaPOD Wrist

Click Here to see the RaPOD Break Apart


The P-POD was designed using the sameoff of the RaPOD Wrist and completes the same 90-90 motion, only it is a passive hand held device. The purpose of the P-POD is to easily represent and demonstrate the idea and motion of spherical mechanisms and PODs. Click the picture to see the P-POD in action.


The Mirror Positioning System:

Solar tracking is used to reflect solar radiation using a mirror positioning system onto a stationary PV array, as shown on the left. The figure to the right shows an example of a mirror under the guidance of a mirror positioning system in current use.


The path has several desired properties:
· Rays must cover the entire path
· No intersection or overlapping segments
· Continuous and sequential path with no repitions desired
· Straight line trajectories for simplicity and easy control
· Parallel/orthogonal segments 

The resulting design is a novel two degree of freedom spherical five-bar mechanism, capable of positioning the mirror as desired. The mechanism utilizes 180 degree link lengths to increase the rigidity. The mechanism design is inspired by the work of Gosselin et al.

The new design has several advantages:
· Novel manipulation of the reflector requires less power than traditional PV array tracking systems.
· Open-Loop solar tracking is based on well known orbital mechanics. There is no need for sensors to determine the position of the sun.
· Two degree of freedom spherical motion yields a large singularity free mirror orienting workspace, an altitude range of 40 to 115 degrees and an azimuth range of 24 to 156 degrees.
See the animation!

Design Team Hardware

The challenge that the Senior design team was give was a spatial assembly problem. The team was to develop a spherical mechanism that could accomplish the task of picking a slide off of a stack and place it in a slide carousel. The two teams, Fall 2007 and Winter 2008, have been given the challenge and they must learn the theory behind spherical mechanisms and PODs while also mastering the design tools and software.

Fall 2007 Team

The Fall 2007 teams goal was to develop the embodiment design of a mechanism for the problem and also complete a prototype of the design manufactured with rapid prototyping technology.


Winter 2008 Team

The Winter 2008 team started with reviewing all the work the Fall 2007 team had accomplished as well as learning the theory and the design tools. They took the protoype that the Fall 2007 team had decided upon and changed how they saw fit and developed their own design for the challenge. By the end of the semester the team will have a working model that will be a complete demostration piece to show the design of PODs, by being able to pick up slides and place them in a slide carousel.



Virtual Models


The Rowbōt is a spherical 4 bar mechanism that is made to replicate the motion that a rower would achieve. The oar is placed in the water for the power stroke then as it leaves the water, it is feathered parallel to the water and returns forward to enter the water for another stroke. The Rowbôt was designed with the help of a University of Dayton Crew member so that its motion would be an accurate representation of rowing.

This material is based upon work supported by the National Science Foundation under Grant No. 0422731 & 0422705.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.