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.

Long overdue update

Hello all! Hope everyone is doing well, as we are past the halfway mark and these 10 weeks are coming to a close (it seemed not that long ago since we all met at Purdue, wasn't it?)

Anyhoo, for the past few weeks, I've just been getting myself more acquainted with the research material: thermoelectric generators (TEG's), their theory, performance, and applications. My project has now been geared towards improving and perfecting upon the system modeling that was done the previous year using MATLAB (had to dust off my notes and refresh on that). I've done lots of literature survey regarding modeling, including system, mathematical, and simulation modeling. I will be receiving aid by a graduate student and hopefully get something running in the next few days. If time permits, I will be experimentally testing a commercially available TEG and comparing it to the system model for validity.

Essentially, as noted in the previous blog post, the application for the TEG in fluid power systems will be implemented in Test Bed 6 (ankle foot orthosis) and for greater scales, Test Bed 3 (hydraulic hybrid passenger vehicle). TEG's will utilize the waste heat from the engines and converting it to usable electric energy to power on small devices (batteries, valves, control circuitry) due to their minimal power output.

The research has been exciting, as its new to me and its potential is remarkable. I was able to test out an evaluation kit that was used from last year's and the phenomenon of thermoelectricity was fascinating. As time is quickly running out, I will be working extra hard to at least complete the system modeling to gain knowledge about the system characteristics for future optimization. 

Haptic Excavator

Hi everybody,

As I stated on my previous post, I'm working on a project for a multimodal excavator. The purpose of this project is to replace the traditional control for a different joystick which allows the operator to have tactile cues, such as feeling pressure, vibration, and also to provide a more intuitive interface, improving the productivity of the operation. I'll post a video showing the device later, but today I'll talk about what I've been doing so far. Over the past weeks my mission has been to revise a mathematical model for the haptic control and for the traditional control. This model includes transfer functions representing the cues (visual, auditory and haptic), the neuromuscular system, force generator, central nervous and task dynamics systems. By combining all these functions, it is possible to come up with a equation of the operator-excavator model. Once I have the equation, I can plug into Matlab and generate some plots to evaluate the systems using some parameters such as stability. Currently, I'm plotting the charts on Matlab and making this evaluations.

I hope everybody is enjoying the experience.

Enio Frota.

Maha Crane

Hello everyone.  My project has switched gears recently.  Originally, I was working on analyzing the load holding valves on the hydraulic crane installed at Maha.  I was able to run tests on the valves that came with the crane and would represent that technology that is currently in the field.  The next step is to replace the valves with new, state of the art valves that were donated to us and run the same tests.  In this way, I could quantify how energy efficient/inefficient the current valves are and how much could be saved with new valves and a closed loop controller.  Recently though, I've been working on improving the simulation for the crane.  Specifically, I'm working on improving the kinematic model.  To do that, I've made the entire crane in Solidworks and then imported the model into MATLAB's SimMechanics.  The current challenge is getting SimMechanics to talk to AMESim (where the fluid model was made), so we can simulate the entire system.  The goal is to validate this model so in the future, they can more easily test different control techniques.

Hi!
So the most exciting thing that happened last week was a lab field trip up to Chicago. We got toured around the Rehabilitation Institute of Chicago and learned about all the prosthetic and orthotic research they are doing up there. There is a lot of cool stuff they can test by tethering to able-bodied people so that the device can be tested on them first. And we saw an exoskeleton!! So the future of bionic suits is not far away :) once they become a little more stable...
Have a great week!
Megan

Hi everyone! In these past few days I have been working on the development of the new prototype interface for a fluid power rescue robot. Based on the data collected on the Tobii machine on the previous experiment that we ran, some suggestions to address the usability issues were implemented. Also, external research was conducted to gather data from usability studies to create a more user-friendly interface. Now, a new experiment will be conducted in the new interface, to make a comparison and see if our goal was achieved.

Hello everyone! The past few weeks, I helped fellow grad students with their projects. I helped them test their noise suppressors in the fluid power oil rig we work on. On top of helping grad students, I am still designing my project, and modeling it using Autodesk Inventor. I am currently trying to optimize the device and trying to make it plausible for the machine shop to machine. Once it's ready, I should have a test ready prototype by the end of July. Other than that, I learned a lot of basic fluid power, acoustics, and even machine design while working on my project.

Closing time.

I'm starting to feel the crunch for time and realizing that there isn't enough time for my project to be finished being that it's a new concept starting freshly anew. We finally bought some magnetorheological fluid to be used as a coupling device in our (Stephan Jean and I) valve concept. The best price we could find was $750 for one liter. Pretty expensive stuff to say the least. As time is drawing to a close, I am finalizing the schematic  and set up of our test rig. I am also delving into the world of electricity and learning about Peak and Hold circuits. Fun stuff.

The Civil Engineering Side

As a civil engineer, my project is rather different than what most of my fellow REU students are working on, and it actually entails two projects related to wind turbines. As a somewhat side project, I am working two days a week with a high school student who is interested in civil engineering. His first week we did an introduction to finding research material and a lesson on statics. His second week he did an investigation into wind turbine towers. Variables he looked at included power, hub height, tower composition, and cut-in and cut-out speeds. This week, his third week, he is using the information he found to determine the amount of steel used in the towers of various wind turbines. He is also using the statics lesson I gave him to practice making shear and moment diagrams. By the end of his six weeks here, we aim to have a basic height optimization for a wind turbine column completed.

As for my project, it started off slowly, but now has direction and potential! Last week I had the pleasure of touring the EOLOS wind turbine after attending the Fluid Power Expo held at the University of Minnesota. This turbine is owned by the university and has been operational for less than a year. Being a new turbine build for research, it is equipped with a variety of sensors on the foundation, column, and the blades themselves. On the foundation of the turbine there are three accelerometers, and these are the sensors I will be working with.

Before I begin working with the massive amounts of data collected on-site, I first need to ensure that I understand the data that accelerometers output. Accelerometers measures three dimensional accelerations. From these accelerations it is possible to determine displacements and orientations. In order to determine if I am calculating the displacements and orientations properly, I am going to build a basic wooden test bed. All smart phones have accelerometers in them, these are the devices which switch the screen orientation when the phone is rotated. Therefore, I can simply use the accelerometer on my cell phone and the wooden test bed to displace my cell phone to a know height and a know orientation. The data recorded and outputted by my cell phone can than be used to validate the MatLab code I will be developing before I apply the code to actual data.

The goal of this project is to determine how the foundation of the turbine is moving and how the accelerometers themselves are moving with respect to each other.

Fun times in Minnesota

Hi everyone!

Over the past few weeks I have been furiously working on understanding Simulink and how exactly I should be attaching a wind turbine rotor, an electric generator, and a hydrostatic transmission to a three shaft planetary gearbox. It has been quite the learning experience to say the very least :) There have been plenty of confusing moments and honestly, I must admit that I owe my grad student, Feng, a gigantic shout-out for all of the wonderful help he has given me thus far: Thanks Feng!

Now, fun things have not just been happening inside the lab. Firstly, Ellen and I were able to attend a Fluid power conference here at the UMN this past week. Not only were the speakers really knowledgeable, but the venders were really chatty and extremely generous with their free stuff (yay for USBs and posters and bags and pens and journals and more!). Moreover, the conference ended with a tour of the large wind turbine located about 40 minutes from campus. It was so amazing to see it up close. You really cannot comprehend the size of these things until you stand directly below them! Secondly, I had a once in a lifetime experience in Starbucks. As Ellen and I were quietly sipping our Cinnamon Apple Spices (if you have not tried this drink you need to! It’s Christmas in a cup, really though…) we were shocked as a bride and groom, still in their full wedding attire, walked into the café. From this point forward I must warn you to stop reading if you are not the hopeless romantic type. Trust me it gets sappy quick J Anyway, not only had these two newlyweds met in a Starbucks, but they made sure to order the exact same coffees they had been drinking during their first encounter. It was absolutely adorable watching them pose for pictures with their mugs. Plus it was wonderful to hear the cashier refuse to let them pay- Minnesota really is full of nice people!

So, fellow REUs, clearly the moral of this story is to start staking out your local Starbucks. Just think, even if you don’t find the man/woman of your dreams at least you will have tried the Cinnamon Apple Spice- trust me, it’s a win-win J      
  

Hey everyone,
Hope everyone's been doing well since the REU bootcamp! My project is to design a pneumatic actuator that can be used to control a robotic exoskeleton/glove that can help rehabilitate a patients hand. When someone has a stroke they commonly suffer from hand plasticity which affects their ability to control and flex their fingers and wrist. So far progress has been a little slow. I have mostly been reading through a lot of papers and searching for different information regarding the typical strength and flexibility of a healthy hand. In addition, I've been looking into the current rehabilitation methods for patient's hands. Recently (in the last 2 days) I have begun modeling an exoskeleton in Solidworks that can be rapid prototyped.

-Josh

These last couple of weeks I have been using CAD to make models for a new case and swashplate in order to eventually get some measurements.  It has been an iterative process, making a design and then adjusting it when I discover some new criteria or encounter new challenges.  Aside from that, my design includes running analysis and researching sensors/talking to sales representatives for instruments companies. 

Reading, and more reading!

Last week, I read about current augmented reality implementations in games, medical field, construction, and military. I am currently reading a 280 page paper on Augmented Reality-Some Emerging Application Areas, looking to gather more information to apply to our area of research. Hopefully, will start applying  my findings next week!!!