prismatic joint

A joint that slides linearly back and forth along an axis, like a drawer opening and closing.

A prismatic joint is a mechanical connection that allows linear sliding movement along a fixed axis—like a drawer, piston, or telescope extending and retracting.

Common Examples

1. Drawer - slides in and out
2. Piston - moves back and forth in a cylinder
3. Telescope - extends and retracts
4. Elevator - moves up and down
5. Robot gripper - opens and closes by sliding fingers apart

Key Characteristics

How It Works

The joint has:

1. A fixed axis (direction of motion)
2. Two connected links that slide relative to each other
3. Limited travel distance (joint limits)

In Robotics

Robot arms use prismatic joints for:

1. Vertical reach (moving up/down)
2. Linear extension (reaching farther out)
3. Precise positioning along one direction
4. Grasping (opening/closing end-effectors)

A robot with mixed joints might have:

1. Revolute joints for rotating and pointing
2. Prismatic joints for reaching and extending

Quick Comparison