> > Glossary for Mechanism Design

Glossary for Mechanism Design
You should be familiar with these terms before creating a mechanism:
 Term Definition Body The basic component of a mechanism model. A body is a group of parts that are rigidly controlled, with no degrees of freedom within the group. Degrees of Freedom (DOF) The potential motion of a mechanism model. Connections act as constraints on the motion of bodies relative to each other, thus reducing the mechanism's total possible degrees of freedom. Every unconstrained body has six degrees of freedom, three translational and three rotational. Dragging Using the mouse to grab and manually simulate a mechanism's movement. Dynamics The study of a mechanism's motion in response to applied forces, taking into account body mass and inertia. Force Motor A force applied to a rotational or translational motion axis to cause motion. Gear Pair A velocity constraint applied between two motion axes. Ground A body in a mechanism that does not move. Other bodies move with respect to the ground body. Kinematics The study of a mechanism's position relative to time. LCS (Local Coordinate System) A coordinate system specific to a body. The LCS is the default coordinate system associated with the first part you define in a body. Placement Constraint An entity in an assembly that places a component and that limits the movement of the component in the assembly. Playback The ability to record and replay the motion of an analysis run. Predefined Connection Set Defines which placement constraints are used to place a component in the model and restricts the motion of bodies relative to each other, thus reducing the assembly's total possible degrees of freedom (DOF). Also defines the kind of motion a component can have within the mechanism. Servo Motor A servo motor defines how a body moves relative to another body. You can place a servo motor on motion axes or on geometric entities, and you can specify the position, velocity, or acceleration motion between bodies. The motion caused by a servo motor will be honored when analyzing the model no matter what actual forces may be required to cause that motion. UCS (User Coordinate System) A coordinate system chosen by the user to act as a frame of reference for the direction of the position, acceleration, or velocity vector. WCS (World Coordinate System) A fixed (global) coordinate system that defines the geometric properties of all the components and bodies in an assembly.