ArticulatedBody

An articulated body is a system consisting of several rigid bodies (links) connected by joints that allow relative motion. The joints impose geometric and kinematic constraints that determine the overall mobility and reachable configurations of the system. Articulation is a central concept in biomechanics, computer graphics, and robotics, where articulated models are used to represent the movement of complex structures more realistically than a single rigid body.

In biomechanics, the human and animal skeleton is modeled as an articulated chain of bones linked by joints such as hinges (hinge joints), ball-and-socket joints, pivots, and sliding interfaces. In robotics, articulated robots, or robotic arms, comprise multiple actuated joints and links arranged in serial, parallel, or hybrid topologies. The joints can be revolute, prismatic, spherical, or more complex, each contributing degrees of freedom that define the mechanism's flexibility.

Kinematic analysis describes the motion by joint variables. Forward kinematics computes the end-effector pose from known joint values, while inverse kinematics determines the joint inputs needed to achieve a desired pose. Dynamic analysis, using Lagrangian or Newton-Euler formulations, relates joint torques to motion, considering inertia, gravity, damping, and external forces. Practical aspects include joint limits, backlash, compliance, and sensor feedback for control.

Applications of articulated bodies span animation and virtual characters, gait analysis, biomechanics research, surgical and industrial robotics, and any domain requiring realistic motion of interconnected parts. Examples include humanoid robots, robotic arms for manipulation, and animated characters in films and video games.