Project Identity. Biomechanics Gait Analysis Lab Week 1 August 28, 2006 Angela Ensor. Work Completed

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1 Project Identity Biomechanics Gait Analysis Lab Week 1 August 28, 2006 Angela Ensor Work Completed Since last semester, Kim informed me that we will be using three dimensional load cells for the force plate, in place of the Thameside one dimensional load cells, which would need to be researched and purchased. In the first week of this semester, I researched load cells at various manufacturer websites. I have sent s to Michigan Scientific Corporation, Interface Advance Force Measurement, and Futek to request information on their three dimensional load cells. To date, I have heard back from Interface, Michigan Scientific Corporation, and Futek. Kim has already called Michigan Scientific Corporation and received further information on the 3-D load cell capabilities and cost. I also visited the websites of AMTI and Kistler for load cells and the Vicon website for motion capture systems. During the first week, my teammates and I met with Dr. Peterson at the UConn Health Center to tour his Biodynamics lab and to discuss the programs and set-up that are used in his lab. His motion system uses seven digital optical cameras, each feeding into hardware devices that interface with the computer and computer program. The camera set-up is adjustable and motion is tracked by reflective balls. He showed us a previously captured motion analysis video. Dr. Peterson has also used load cells for force measurement and force sensitive resistors for pressure measurement. After discussing our senior design project, Dr. Peterson provided his feedback based on his professional experience. According to Dr. Peterson, portions of our project will require considerably more time than allotted. He was especially concerned with building a motion system, since calibrating the cameras, creating the computer program, and getting the set-up configure properly running took his team (including a graduate student) a year to complete. Although he believes that the force plate will be challenging, he feels that it can be accomplished in a semester, if we work hard and plan well. The load cells

2 must be calibrated in three directions at varying forces, so that we can assign quantities of force to the voltages output by the load cells, which, from his experience, is very challenging and time consuming. In building the force plate, we will need to build an amplifier for the signal output from the load cells. We will also need to build a modularized platform, for easy set-up and storage. We will also have to build the computer program, of which part of the challenge will be determining how best to use the output from all four load cells. His recommendation is to focus on getting the force plate completed and give the motion system to the next senior design group. He said that he is willing to get involved with any questions or assistance we may need. Future Work Our first priority is to determine what materials we will need to order and get them ordered as soon as possible. During the following week, I will follow-up with Futek and Interface to get further information and price quotes on their 3-D load cells. I will also assist in researching any other remaining materials that we need to order and help to get the materials ordered. We will need to consensus on all of the materials we are going to use for the force plate and platform so that we can move ahead with ordering those materials as well. Project Review At this point, I feel that our meeting with Dr. Peterson revealed the extent of the difficulty of this project that we were not aware of last semester. Having discussed the project with Dr. Peterson, we have discovered that, given the degree of difficulty and time that is required to accomplish this project, that it is necessary to discuss this matter with Dr. Enderle. As for our research into the three dimensional load cells, having met with Dr. Peterson and contacted several manufacturers, I feel we are making good progress on that task. Hours Worked 8 hours

3 Project Identity Biomechanics Gait Analysis Lab Week 1 August 28, 2006 Kimberly Carr Work Completed After our final presentation last semester we discussed using three dimensional load cells instead of the four Thameside load cells which were previously provided to us with Dr. Peterson from the UConn Health Center. Since then I have been researching 3-D load cells from a number of manufacturers including Kistler, Michigan Scientific Corporation, Bertec, and Interface Advance Force Measurement. Unfortunately, we do not currently have a budget for this design project and the load cells we have information on range anywhere from $2,120 to $3,835 each. On Wednesday, August 30, 2006 my teammates and I met with Dr. Peterson at the UConn Health Center to tour his Biodynamics laboratory and talk about our concerns and questions regarding our senior design project. We mainly focused on the force plate issues: load cell choices and placement, top and bottom plate materials, as well as fabrication methods. Dr. Peterson offered the idea of simply using one load cell at the center of the plate to cut down cost and calibration. This idea seemed like our best option until I discussed this with engineers at many of the load cell manufactures, who told me that the bending moments created if someone were to step on the far edge of the force plate will be too much for the sensitive load cells to endure and may cause serious damage to the load cell if placed in the center. While at the Biodynamics lab we also discussed our plans for an optoelectronic system incorporated into our design project. Dr. Peterson was kind enough to demonstrate his elaborate system of 7 infrared cameras and computer program. He informed us that he thinks an optoelectronic system should only be included into our project once we have completed the force plate due to time and budget constrictions. Dr. Peterson has been a great help in trying to figure out some important guidelines for our design project and has informed us that he is willing to

4 help direct us on future project questions especially concerning the calibration of our fabricated force plate. Another lingering decision is the choice of metal material that we are using for the top and bottom plate of the force plate. Previously, we wanted to use 0.5 inch 6061 aluminum alloy which we were going to purchase from the Machine Shop at UConn, but unfortunately, some of the load cells we are looking at recommend using crucible stainless steel due to the preloading needs of the load cells. Future Work By Friday, September 8, 2006 we will decide on which load cells and plate materials to purchase and put in a purchase order so that we get them in as soon as possible. Before the end of this month, I hope to begin fabrication of the force plate so that we do not fall too far behind on this design project and have time to test the force plate and create a LabVIEW software program to perform data analysis. Project Review At this point in time, I think it is imperative that we discuss the budget situation with our client and advisor Dr. Enderle in order to get a grasp of what can be accomplished with this design project before the end of the Fall semester. Right now, I would say that the two load cells that are our best options are the: 1. Michigan Scientific Corporation: TR3D-A-1k $2, Kistler Instrument Corporation: 9250A4 $3,189 Hours Worked 10 hours

5 Project Identity Biomechanics Gait Analysis Lab Week 1 August 28, 2006 Omar Chawiche Work Completed Since last semester the components of our project has been partially changed and redesigned. The original design was based on using 2D load cells that we already have in stock, in order to capture 2D images for the subject, than our client suggest that 3D images as a results will better and will provide more information about the movements of the subject. In order to capture 3D images, a 3D load cells will be needed that we don t have it in stock. A research was done to find companies that sell 3D load cells and how much they run for, and as conclusion, we found out that only few companies manufacture this type of load cells, and the picture below show some of it. Figure 1: The MTA400 Tri-Axial Load Cell Figure 2: The MTA500 Multi-Component Tri-Axial Load Cell The MTA400 Tri-Axial Load Cell offers an excellent solution for measuring Fx, Fy, and Fz loads and it is made from Aluminum, where the MTA500 is available in both Anodized Aluminum and also Stainless, which give us the flexibility of choosing the metal in order to fit best with the force plate.

6 One of the companies that we contacted, located in Michigan, offers a pre-calibrated load cells, in which it will save us time that we are going to spend on calibrating these load cells. These pieces cost more than the original one will cost, so know it all depend in our budget that haven t been specified so far. A decision hasn t been made yet concerning purchasing any of these items, in which it depends in our client Dr. John Enderle. Another part was changed from the original design is the metal that we have to use to built the force plate. After some research that was done over the summer, it was found that it is best that the force plate will be made out of the same kind of metal that is used for the load cells. The reason for that is, if the same metal was used, the more durable and more stable the force plate will be and also will give better results. During the first week of this project, a meeting was held at the University of Connecticut Health Center with Dr. Donald R. Peterson who is the director of the Biodynamic laboratory at the university of Connecticut health center. Dr. Peterson had an experience of a gait analysis lab throughout graduate students who worked on building a similar gait lab to the one we are working one. The meeting was very helpful, and it clarify different things for us, such as the quantity of load cells to be used in the project and the most important thing was explaining what should be done in order to built a gait analysis lab and how much it requires in order to complete such a project. Future Work During the second week of this semester, a meeting will take place between the team members and our client Dr. John Enderle, to decide what will be our budget for this project and to clarify what we are able to finish during the period of the 12 weeks left. After the meeting, the necessary items will be purchase as soon as possible and will be chipped over night, so we can make up some of the time that we lost already the past week and a half.

7 Assuming that those items will arrive next week, the building of the force plate will start using the machine shop. Project timeline: Week #2 Week # 3 Ordering the necessary items Start building the force plate Project Review As a result of last-minute action by changing some of the components of the project, we are behind on our timeline. While other groups are currently working with material on their designs. Our main focus now is to place the order of our load cells and the metal sheet as fast as we can in order to get back to the position we should be in. Hours Worked 7 hours