Following are the three types of constrained motions,…
Completely Constrained Motion:- When the motion between a pair is limited to a definite direction irrespective of the direction of force applied, then the motion is said to be a completely constrained motion. for example, the piston and cylinder (in a steam engine) form a pair and the motion of the piston is limited to a definite direction (i.e. it will only reciprocate) relative to the cylinder irrespective of the direction of the motion of the crank. The motion of a square bar in a square hole, and the motion of a shaft with collars at each end in a circular hole, are also examples of completely constrained motion.
Incompletely Constrained Motion:- When the motion between a pair can take place in more than one direction, then the motion is called an incompletely constrained motion. A circular bar or shaft in a hole is an example of an incompletely constrained motion as it may either rotate or slide in a hole. Both motions have no relationship with the other.
Successfully Constrained Motion:- When the motion between the elemnts, forming a pair, in such that the constrained motion is not completed by itself, but by some other means, then the motion is said to be successfully constrained motion. The motion of an I.C engine cylinder are the example of sucessfully constrained motion.