Pelvis Model

Rigid Bodies on Cassie

--- Pelvis --- Yaw --- Hip --- Thigh --- Knee --- Shin --- Tarsus --- Toe ---
--- Knee Spring --- Heel Spring --- Toe Output Crank --- Plantar Rod --- Achilles Rod ---

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Pelvis

Body Properties:

m = 10.33 kg

    | 94158 |  169  | 15026  |                   
J = |  169  | 84066 |  516   | kg.mm^2
    | 15026 |  516  | 112770 |

COM = [ 50.7 | 0 | 28.4 ] mm

Pelvis COM --> Abduction gimbal origin

     | 0  | 0 | 1 |  21 |                   
T1 = | 0  | 1 | 0 | 135 |
     | -1 | 0 | 0 |  0  |                  
     | 0  | 0 | 0 |  1  |

Abduction gimbal origin --> Yaw gimbal origin

     | 0 | 0 | -1 |  0  |                   
T2 = | 0 | 1 | 0  |  0  |
     | 1 | 0 | 0  | -70 |                  
     | 0 | 0 | 0  |  1  |

Abduction Motor Specs

ROM = -15 to 22.5 deg
Gear ratio = 25:1 speed reduction
Max motor torque = 4.5 N-m
Max motor speed = 2900 rpm
Motor shaft inertia = 61 kg.mm^2