Unstable Solutions LLC. An Affiliate of Penn State Engineering

Pennsylvania State University Department of Mechanical Engineering 316 Leonhard Building

Pendubot: The Perfect Balance Between Learning and Fun!

Unstable Solutions is a company based out of State College Pennsylvania that focuses on developing laboratory equipment for ME440, Modeling Dynamic Systems, students. We designed a system called a pendubot. It is an under actuated link system that will balance in several configurations with proper controls. Using ProEngineer and Solid Works, we designed a prototype. After analysis and testing, revisions were made. The final design was sent to SkyTop Machine to be manufactured. The Pre-Lab and Lab Manual have also been finalized with the completion of student test evaluations. Below is more about the several designs and what the students will be expected to do in the Lab.

Prototype I

Prototype I seen below was the first attempt at building a working Pendubot. The bot worked; however, it had several flaws:

-The links were heavy so motors overheated.

-The edges were sharp: therefore, it could be very dangerous with an incorrect control system.

-The system experienced unwanted vibration from motor which affected the balance capability.

-The design created radial forces on the motor and encoder shafts.

Prototype II

Prototype II was the next design iteration. The sharp edges were removed; however, we realized its flaws before testing:

-The links were heavier than Prototype I.

-The bend radius was too large so the pendubot was bulky.

-The radial forces were higher than Prototype I.

-Since it was the same motor mount, the vibration would still be an issue.

Prototype III – Final Design

Prototype III became our final design. The new design eliminated the problems that were found in the other two:

-Ball bearing – Eliminated radial forces

-¼” Aluminum Tubing – Lightweight

-C-shaped Motor Mount – Eliminated Vibration

-Built on Clamp

-Set Screws – Easy to assemble

The Lab Portion

Below is the Simulink controller that the students will build during the lab. It uses state feedback and the Matrix Gain K to balance the lower link. The gain K will be found after they complete the Pre-lab. The Pre-lab will help the students solve the A and B matrices required to control the system. We tested the lab with several former ME440 students and used their feedback to make a final pre-lab and lab manual.

We are currently completing the lab set up in 320 Reber.

The lab will be available in the Fall 2006 semester to ME440 students.

For more information contact Matt Cuppett