17.3 Kinematic Analysis

Mobility

Our climbing subsystem has one degree of freedom, as calculated below:

M = 3(L-1)-2J1-J2 = 3(4-1)-2(4)-0 = 1 DOF

Our rotating subsystem has one degree of freedom, as calculated below:

M = 3(L-1)-2J1-J2 = 3(2-1)-2(1)-0 = 1 DOF

Our system has two degrees of freedom, as calculated below:

M = 1 + 1 = 2 DOF

Ideal Motion

The four-bar mechanisms are shown in motion in Figure 3.1 below with their resulting motion profile in Figure 3.2 below. The vertical portion of the motion profile is what we will be using to scale the vertical surface.

Figure 3.1. GIF of all 4 four-bar mechanisms during animation.

Figure 3.2. Motion profiles of all 4 four-bar mechanisms.

Kinematic Analysis

For each of the four-bar mechanisms in Figure 3.1 above, the position, velocity, and mechanical advantage have been calculated as a function of angular position; the results are presented below in Figures 3.3, 3.4, and 3.5, respectively.

Figure 3.3. Position analysis of all 4 four-bar mechanisms, starting in quadrant 1.

Figure 3.4. Velocity analysis of all 4 four-bar mechanisms, starting in quadrant 1.

Figure 3.5. Mechanical advantage of all 4 four-bar mechanisms, starting in quadrant 1.