10.3 Kinematic Analysis
Ideal Motion:
Motion Profiles of End Effector:
Mechanical Advantage for Hand Crank:
Mobility Calculation: (systems and subsystems):
Gruebler’s Equation:
Number of Links: 7
Number of 1 DOF Joints: 8
Number of 2 DOF Joints: 0
M = 3 ( 7- 1) - 2 (8) - 1 = 1 DOF
Note: Because gears are higher pair joints, deduct 1 DOF.
Grashof Condition:
Each four-bar is identical
L1 = 300 mm, L2 = 50 mm, L3 = 50 mm, L4 = 50 mm
S + L = P+ Q
This mathematically satisfies the Grashof inequality and suggests that both four-bar links are able to make a full rotation if permitted by the physical limitations of the system.
However, the system is physically limited when the links, which exist on the same plane, begin to touch. The system is further limited by the physical presence of the base, meaning that when the end effectors of the four-bar coincide with the base, motion is also constricted. Therefore, the real range of motion for the input link is from ~-45 degrees to ~80 degrees in the final model.
Force Analysis:
Animation: