Feasibility Testing Report Muscle Optimization Stage I

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1 Feasibility Testing Reprt Muscle Optimizatin Stage I Team: P15001: Active Ankle Ft Orthtic Engineer: Nah Schadt Mechanical Engineer Engineer: Tyler Leichtenberger Mechanical Engineer Test Date: 10/14/2014 Related System: Actuate Muscle (ABBBBA) The reasn fr this test is t find: a) What supplies are needed t make an air muscle? b) Hw can we regulate the pressure? c) What is the relatinship between strain and pressure? d) What is the relatinship between frce and strain? e) What is the relatinship between strain and size? f) What are the next steps fr muscle ptimizatin stage II? Testing Prcedure Supplies 1. Orange Muscle (M1) a. 4.5 inch range muscle sleeve b. 4.5 inch latex surgical tubing c. Plastic end cap plug d. Plastic inlet fitting e. Wire ties f. Wrm clamp g. Black air line tubing (apprx. 1 ft) 2. Red Muscle (M2) a. Premade with unknwn cmpnents 3. Pressure regulatr 4. Transparent air line tubing (apprx. 4in) 5. 1/4in quick cnnect t shp tank quick cnnect (2 pieces screwed tgether) 6. Shp air tank 7. Packing tape/wire ties 8. S-carabiner 9. Key-ring 10. Ruler (2) with clamp t increase length 11. Weights (see Table 1: Individual Weights)

2 Setup The weights used in the tests cnsisted f the fllwing individual weights: Weights lbs Weight (1) 4.59 Weight (2) 4.63 Hangar (3) 0.93 Dumbells (4) 2.00 Table 1: Individual Weights The weights were cnfigured in ne f three arrangements as shwn in Table 2: Weight Cnfiguratin lbs Cnfig. # Tw main weights (1)(2)(3) 10.1 W1 One main weight (2)(3) 5.6 W2 Hangar and dumbells (3)(4) 2.9 W3 Table 2: Weight Cnfiguratins Tw muscles were testing in this phase. The first (M1) was an range muscle that was cnstructed in huse with supplies n hand in the shp as listed in Supplies. The secnd (M2) was a lnger Red muscle that was fund premade in the BAD Lab. The apprximate initial lengths were measured as well as the inflated width at 60psi with n lading. Muscles Muscle # Width 60 psi & 0 lbs L 0 (in) Orange - Hmemade M Red - Premade M Table 3: Muscle Infrmatin A series f six tests were cnducted since there were tw muscles and three weight cnfiguratins. Table 4 is prvided as a reference f the test cnfiguratins. Ttal Cnfiguratin Test # lbs Test Name Orange (M1) & W1 Test M1) 10.1lb Orange (M1) & W2 Test M1) 5.6lb Orange (M1) & W3 Test M1) 2.9lb Red (M2) & W1 Test M2) 10.1lb Red (M2) & W2 Test M2) 5.6lb Red (M2) & W3 Test M2) 2.9lb Table 4: Test Cnfiguratins Reference The test rig was set up as shwn in Figure 1. The muscles were fixed t an verhang and attached t the weight hangar. The initial height frm the flr (H_0psi) was measured separately fr each test and used as a reference fr crrespnding displacement.

3 Figure 1: Test Rig Prcedure The tests were perfrmed by varying the pressure and measuring the height frm the flr. There is little deflectin frm 0-30psig s measurements began at 30psi and increased by 5 r 10psi as shwn in Table 5. Pressure (psig) Ntes Test Leak and n change Raw Height Test Test Leak at 60 Test Test Test Table 5: Raw Height Data All units in the test matrix are inches except fr the Pressure which is psig. Test 1 pushed the upper limits and fund that the hmemade muscle leaked at 80psi with n change in deflectin frm 70psi. (it als leaked at 60 psi in Test 3. Results In rder t better interpret the data, the change in deflectin fr each test was calculated and arranged in Table 6.

4 Deflectin Table 6: Deflectin and Pressure Results Pressure (psig) M1) 10.1lb M1) 5.6lb M1) 2.9lb M2) 10.1lb M2) 5.6lb M2) 2.9lb The results f Table 6 were pltted directly int Figure 2 t shw the relatinship between strain and pressure (c). Figure 2: Muscle Pressure and Deflectin In rder t better visualize the relatinship between strain and frce, the data frm each muscle was pltted separately.

5 Figure 3: Muscle 1 Strain and Pressure Figure 4: Muscle 2 Strain and Pressure Figure 3 and Figure 4 demnstrate that the amunt f strain tends t decrease with increased frce (d). This trend is mst visible by bserving the gap between the plts f 10.1lbs and 5.6lbs f frce. Between 2.9lbs and 5.6lbs there appears t be much less f a disparity and in Figure 3 there appears t be a slight increase in strain frm 2.9lbs t 5.6lbs f frce. This discrepancy is small and may be due t varius measurement errrs as well as uncertainty in the muscles and test repeatability.

6 The relatinship between strain and size (e) can be seen by cmparing the perfrmance f the tw muscles under similar lading. Figure 5: Strain and Pressure 10.1lb Weight Figure 6: Strain and Pressure 5.5lb Weight

7 Figure 7: Strain and Pressure 2.9lb Weight Figure 5, Figure 6, and Figure 7 cnfirm that the larger muscle (M2) cnsistently yields mre strain than the smaller muscle (M1). Cnclusins a) What supplies are needed t make an air muscle? The team nw has an understanding f the necessary supplies and cmpnents which ultimately affect the BOM. b) Hw can we regulate the pressure? The team learned that there are functinal pressure regulatrs in the BAD Lab that can be quickly cnnected t the shp air tank. c) What is the relatinship between strain and pressure? After 30psig the strain increases dramatically with pressure as shwn in Figure 2. d) What is the relatinship between frce and strain? Strain decreases with frce as bserved in Figure 3 and Figure 4. e) What is the relatinship between strain and size? Strain increases with size as shwn in Figure 5, Figure 6, and Figure 7. f) What are the next steps fr muscle ptimizatin stage II? See belw. Next Steps A. Identify Needs frm Other Tests B. Design Muscle C. Cnstruct and Test Optimized Muscle Identify Needs frm Other Tests The next step is t cnstruct an ptimized muscle based n limits, ideals, and infrmatin frm the fllwing tests:

8 I. CAIR Tank Regulatin and Capacity test a. Need: Pressure ceiling b. Need: Vlume limitatins & mdel cnfirmatin II. Lwer Ft Attachment Test a. Need: Lcal fabric strain b. Need: Actual lifting frce required III. Upper Ft Attachment Test a. Need: Lcal fabric strain b. Need: Frce ceiling IV. Muscle Optimizatin Stage I a. Fund: Pressure vs. strain, relatinship & empirical data b. Fund: Frce vs. strain, relatinship & empirical data c. Fund: Size vs. strain, relatinship & empirical data Design Muscle After all the infrmatin abve is btained, the next step wuld be t analyze all the varius cnstraints and identify the fllwing ptimized muscle parameters: Length Width Frce Strain Capacity Operating Pressure Plug and fitting specs Cnstruct and Test Optimized Muscle Once the stage II ptimized muscle is designed, it must be cnstructed and tested t reveal further iteratin requirements.