Prosthetic Arm Force Reducer Team 1 – Halliday's ... - Ohio University

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$Introduction to Numerical Math and Matlab ... - Ohio University$

Using simple static analysis, the resulting grip force (Fg) can be calculated by summing the moments about the pivot point on the right side: The term “Fr” in these equations is equal to k*xo (via Hooke’s Law), where “xo” is the elongation of the rubber band at the closed position of the hooks. UDetermining Needed User InputU: Figure 6.1.3 shows “top-down” views of the mobile hook in the closed (left) and partly open (right) positions Fr = Force of rubber band Dr = Distance from rubber band to pivot Fc = Cable force supplied by user (constant) Dp = length of cable post Figure 6.1.3 – Top-Down FBD “Fc” is considered a constant for this section, and it is assumed that the user is applying maximum force throughout the entire opening range of the hook. It is also assumed that the hook runs through a guide before it connects to the post on the hook. This keeps the user force vector in one direction at all times. Since torque is what we are after for this section, the forces “Fr” and “Fc” have to be resolved, so they are perpendicular with “Dr” and “Dp”, respectively. Figure 6.1.4 (as seen on the next page) shows the components needed to resolve the user input force (Fc). (2) (3) (4) 24
Figure 6.1.4 – Input Force FBD The interior angle between Fc and Fc’ is equal to Ѳ. Therefore, both the resolved force, and subsequent torque can be determined easily: (user induced torque) Figure 6.1.5 shows the components necessary to resolve the force due to the rubber band. Figure 6.1.5 –Rubber Band FBD Please note that the rubber band force (Fr) will increase as a function increasing Ѳ. Therefore, Fr must be defined functionally: For this equation, “Fro” is equal to the rubber band force at Ѳ =0 (which is equivalent to the “Fr” from Figure 6.1.1). Also, “x” is equal to the amount of additional elongation the rubber band (5) (6) (7) (8) 25
Page 1 and 2: Prosthetic Arm Force Reducer Team 1
Page 3 and 4: 1.0 Introduction Limb loss generall
Page 5 and 6: 2.1 Weighting of Customer Needs Wei
Page 7 and 8: which could limit the use of rubber
Page 9 and 10: design of the two load hook allows
Page 11 and 12: Fig. 4.1.6 - Utah Arm 3 MAGNUM Para
Page 13 and 14: Feature Hosmer Model 7 Work Hook Ot
Page 15 and 16: hook is closed. The harness idea is
Page 17 and 18: purchase it. Safety is another exte
Page 19 and 20: Figure 5.1.2 - Solid Edge Model of
Page 21 and 22: 5.1.4 Concept D - Upgraded Springs
Page 23: 6.0 Concept Selection 6.1 Data and
Page 27 and 28: Since the torques of the both the r
Page 29 and 30: Once the design of the system was u
Page 31 and 32: 7.0.3 Professional/Ethical Standard
Page 33 and 34: Table 7.0.2 - Risk Priority Number
Page 35 and 36: The actual FEA testing involved uti
Page 37 and 38: Another sector that has aided in ou
Page 39 and 40: Figure 7.0.10 Cable Path for Mechan
Page 41 and 42: 7.2.1 Rings (Part #’s THH-001 [El
Page 43 and 44: 7.2.4 Collars 1) Using lathe turn o
Page 45 and 46: 7.3 Cost Analysis & Bill of Materia
Page 47 and 48: manufacturing costs are $525.00. Th
Page 49 and 50: operation necessary. This convertib
Page 51 and 52: Appendix A - Split Hook Sample Calc
Page 53 and 54: George Platounaris - Interview (12:
Page 55 and 56: Appendix C - Tim Lang’s Forearm D
Page 57 and 58: Health Progress, “Disables Enteri
Page 59: Drawing Package 1. THH‐001……

Prosthetic Arm Force Reducer Team 1 – Halliday's ... - Ohio University

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