You are asked to design an arm-actuated propulsion system for a wheelchair. A four-bar path generation...

 

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You are asked to design an arm-actuated propulsion system for a wheelchair. A four-bar path generation mechanism with prescribed timing is needed as part of the system. The three prescribed path points (C₁, C₂ and C3), shown in the figure, have been determined to be the most efficient arm motion. The movement of the coupler path point, C, provides the input, while the output is a rotation of the large wheel. The suitable location of the two fixed pivot points A, and B, have also been determined and shown in the figure. The mechanism will include a clutch at A.. The clutch will slip when the grip is returned from C, to C₁ along the same path. Use graphical method (CAD) and specify the length of all links. The locations of Bo, C₁, C₂ and C3, with respect to the fixed pivot point A, are given. Deliverables; 1) (10 points) - Drawing(s) showing the location of the moving pivot "A". Use the following timing: 92 = 38° and 93 = 80° (rotation of the link A.A for the prescribed path of point C) 2) (15) points - Drawing(s) showing how the moving pivot point B was determined. Clearly label all joints and links. Show all construction lines (use dashed lines or different colors). 3) (5 points) – Draw the mechanism in the three position and specify the length of all links. The drawing below is to scale. Reproduce the general shape of the wheelchair. Use the information given below to locate the important points. A. (0,0), B. (1.5, -.3), C₁ (0.61, 1.95), C₂ (1.22, 2.25) and C3 (1.93, 2.3), Radius of the back wheel = 1.125 Shoulder + 1.125 2 Elbow Extension Position Y Grip You are asked to design an arm-actuated propulsion system for a wheelchair. A four-bar path generation mechanism with prescribed timing is needed as part of the system. The three prescribed path points (C₁, C₂ and C3), shown in the figure, have been determined to be the most efficient arm motion. The movement of the coupler path point, C, provides the input, while the output is a rotation of the large wheel. The suitable location of the two fixed pivot points A, and B, have also been determined and shown in the figure. The mechanism will include a clutch at A.. The clutch will slip when the grip is returned from C, to C₁ along the same path. Use graphical method (CAD) and specify the length of all links. The locations of Bo, C₁, C₂ and C3, with respect to the fixed pivot point A, are given. Deliverables; 1) (10 points) - Drawing(s) showing the location of the moving pivot "A". Use the following timing: 92 = 38° and 93 = 80° (rotation of the link A.A for the prescribed path of point C) 2) (15) points - Drawing(s) showing how the moving pivot point B was determined. Clearly label all joints and links. Show all construction lines (use dashed lines or different colors). 3) (5 points) – Draw the mechanism in the three position and specify the length of all links. The drawing below is to scale. Reproduce the general shape of the wheelchair. Use the information given below to locate the important points. A. (0,0), B. (1.5, -.3), C₁ (0.61, 1.95), C₂ (1.22, 2.25) and C3 (1.93, 2.3), Radius of the back wheel = 1.125 Shoulder + 1.125 2 Elbow Extension Position Y Grip

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Answer In path generation a point on the link has to be guided Through the required positio... View the full answer