Kinematics - An Example Continued


Define and discuss your assumptions. We desire to study the motion of the upper extremity. Assume planar motion. Let us further assume that the shoulder does not translate. The motion of the fingers will be neglected.

Create a model of the body segments of interest. The figure below is a possible representation of the upper extremity. This is a three-link model with Links L1, L2 and L3 representing the upper arm, forearm and hand respectively. Joints J1, J2 and J3 are the shoulder, elbow and wrist. The centers of mass for each link are cm1, cm2 and cm3. Note: The center of masses are not at the midpoints. The distance from Joint J1 to the center of mass is r1. Similarly, r2 and r3 will be used for the other links. Point P marks the distal end of Link L3.



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Support for the development of this module was provided by the National Science Foundation and The Cooper Union for the Advancement of Science and Art.

Please send questions or comments to Professor Ron Adrezin or Professor Daniel Raichel.