What do Denavit–Hartenberg parameters describe in a serial robot manipulator?

• A. Four parameters per joint/link that define the transform from frame i-1 to i.
• B. A matrix of end effector forces.
• C. The set of joint torque limits.
• D. The joint velocity profile used in planning.

Answer: (A)

The main idea being tested is how we describe the relative motion between consecutive parts of a serial robot using a compact set of numbers. Denavit–Hartenberg parameters provide four numbers for each joint that define the transform from frame i-1 to frame i. These four parameters—link length (a_i), link twist (alpha_i), link offset (d_i), and joint angle (theta_i)—fully specify the homogeneous transformation that carries coordinates from the previous frame to the next. In the common convention, this transformation is obtained by multiplying rotations and translations in a specific order, yielding the pose of the next frame in terms of the current joint variable. This framework allows you to chain these per-joint transforms to compute the end-effector position and orientation for any given set of joint angles (or displacements). It’s a kinematic description, not a map of forces, torques, or velocity profiles.