Greetings from GA

Hello everyone!!!

Everything is going pretty well here! I got my energy harvester prototype machined, and after a few more adjustments, it should be ready for preliminary testing. Other than that, it's been somewhat hectic writing a paper about my prototype for my professor, and slowly working on the report/poster for the CCEFP deliverable, while also trying to finish up the actual prototype. But nonetheless, everything's been pretty good here at GA Tech (minus today's rainy weather).

Interesting/unrelated news: They're actually currently shooting the movie "The Internship" here on GA Tech campus! They altered a lot of the buildings to make it look like Google headquarters and apparently Vince Vaughn and Owen Wilson have been walking around campus, although I've never ran into either of them.

-Daniel Kim

Crane Update

With the help of my graduate mentor, I recently replaced the over center valves on the crane.  The new valves have two important features.  The first is that they have twice the pilot ratio of the old valves (and the valves that are typically in use in the field).  This basically means that the new valves are lot more efficient, but possibly more unstable.  The second advantage of the new valves is that we can adjust the pressure that is required to open them.  Lowering the pressure means less energy is needed, but again may lead to instabilities.  My graduate mentor is developing a pressure feedback controller as part of his thesis so we can make the valves much more energy efficient while making sure the system stays stable.  We have not operated the crane since the valve replacement, so we're hoping everything goes well once we turn the pump on...

Based on the theoretical performance of the new valves, I was able to calculate that we could achieve upwards of 40% energy savings over the old valves.  This depends heavily on the load that is on the crane and what cycle the crane is put through, but we are still very happy with the energy savings that could be realized if the controller can be developed to keep the crane stable.

This is our last week of the program here at Purdue, so now a lot of my time is spent finishing up presentations and paper.  The REU program this summer was a great experience and I hope everyone else enjoyed it as much as I did!

Hello Again

Hi Everyone!

I hope you are all enjoying the last few weeks that we have left with CCEFP. I can’t believe time has gone by so fast! Since my last blog post, I have built the majority of my Simulink model for my hydro-mechanical wind turbine. In fact, I pressed ‘run’ for the very first time on Monday morning. However, with the push of that button I began the frustrating task of debugging… inevitably, this week is going to be a long one.

Nevertheless, I do have a fun tale to tell about last week. On Tuesday, I went with fellow summer researchers to visit the University of Minnesota’s Morris campus. On this campus there are two large wind turbines, a biomass-burning plant, and a silver LEED certified building which heats its rooms and water with mostly solar thermal energy. The entire tour was led by three wonderfully knowledgeable speakers, and was extremely motivational.  Seeing how the campus incorporated all of these state-of-the-art, sustainable technologies, renewed my faith in America’s green energy sector! I really cannot wait for more of these products to find their way into modern homes and communities.

If you ever find yourself out in Minnesota, make sure you take a day and visit the Morris campus. It is definitely worth the drive!      

Hi everyone!

So this week was exciting because we had a TB6 conference call and Becca, Ellen and I were all there! I am finally starting to get a good direction for my project since I stopped being asked to do other tasks. The process has been really interesting trying to breakdown what is useful for us to do and what would be useful to do for a paper (the community's use).

Hope everyone's having a good time!
Megan

Power steering system update

In our project, the primary concern is related to the articulated steering structure. Articulated steering is actually rotating the whole front frame which requires a significant steering torque. However, The steering wheel is connected to the proportional rotary valve directly. That means considerable energy loss will occur at the valve.

In order to reduce the energy consumption, we will implement the DC system. However, haptic feedback won’t be available in this case, because the steering wheel no longer has a direct linkage with the steering cylinder. So we will use a sensor to measure the steering wheel position and a torque feedback device to replicate the road feel. A controller will be used to communicate the hydraulic pump and steering interface. 

In general, we will have improvements in 3 aspects: efficiency, safety and productivity

A lot of work has demonstrated the improved efficiency of the displacement controlled actuation by getting rid of the throttling loss across the valve. Next, stability is normally an issue for articulated steering vehicle, like jackknifing or snaking. However, with the new system, the active steering assistance can modify the driver’s input to stabilize the vehicle. We will also use progressive steering to help driver be more productive. That means in low speed situation, driver will experience faster and easier steering than that in high speed, in which case the resistive force will increase for better stability.

Haptic Devices

Hello everyone,

I hope each and everyone of you are enjoying your time thus far. For the past couple of weeks, I have been working on two haptic devices. The 1st was the Phantom Omni; which I tried to test but did not work out as planned. The Phantom Omni is a haptic devices makes it possible for users to touch and manipulate virtual objects. Due to some technical difficulty, I could not use it as I wanted to. Though we are still using the 2nd haptic device. The 2nd haptic device is the Phantom Premium 1.5 which provides a range of motion approximating lower arm movement pivoting at the elbow. Those in industry believe this haptic device to be better than the Phantom Omni.

The Premium 1.5 device includes a passive stylus and thimble gimbal and provides 3 degrees of freedom positional sensing and 3 degrees of freedom force feedback. Since it has been connected, I mainly just played with it using the graphic excavator and loading and unloading sand. While the Phantom Omni provides six degree-of-freedom positional sensing, Portable design and compact footprint for workplace flexibility, Comfortable molded-rubber stylus with textured paint for long term use and secure grip, removable stylus for end-user customization and two integrated momentary switches on the stylus for ease-of-use, and end-user customization.

Until next time, Stay Up!!!!

Hi everyone! In these past few days, we ran the pilot test to study the usability of a prototype interface for fluid powered rescue robots. The experiment consisted on the participants running two interfaces (the previous one, and the new one, with the changes suggested in our first study). Their eye movements were recorded, and the data collected was compared to analyze if we were able to improve the usability of the interface. Good results have been achieved, and now we will probably run the real experiment.