A kinematic chain is a series of interconnected links and joints that work together to create movement. Each link can be a rigid body, while the joints allow for relative motion between the links. Kinematic chains are essential in mechanical systems, such as robots and machinery, where they help convert input motion into desired output motion. These chains can be classified into different types, such as open and closed chains. An open kinematic chain has a starting and ending link, like a human arm, while a closed kinematic chain forms a loop, like a bicycle pedal system. Understanding kinematic chains is crucial in fields like mechanical engineering and robotics.