Which term describes a robot with three sliding joints, two of which are orthogonal, also known as a rectilinear robot or x-y-z robot?

• A. Cylindrical robot
• B. Spherical robot
• C. Cartesian coordinate robot
• D. Rectilinear robot

Answer: (D)

The key idea is straight-line motion along three perpendicular directions using sliding joints. A rectilinear robot uses three linear actuators arranged to move along x, y, and z, so the end effector translates in 3D without rotating. This is exactly what “three sliding joints, two of which are orthogonal” describes, and why the term rectilinear robot (also known as an x-y-z or Cartesian robot) is the best fit.

Other architectures describe different motion types: cylindrical robots combine rotational movement with linear slides, and spherical robots rely on rotary joints to reach orientations around a central point. The term Cartesian coordinate robot is often used synonymously for the same three-translation setup in some contexts, but the description given aligns most directly with rectilinear motion, making rectilinear robot the most precise label.