What does Yoshikawa manipulability quantify?

• A. It is a measure of the robot's physical size.
• B. A scalar measure from the Jacobian indicating how easily the manipulator can move in arbitrary directions.
• C. The determinant of the inertia matrix.
• D. The quality of sensor data.

Answer: (B)

Manipulability quantifies how easily the end-effector can move in any direction from a given configuration, and this is determined by the robot’s Jacobian. Yoshikawa’s measure is a scalar derived from J, defined as w = sqrt(det(J J^T)). It captures the ease of motion in all Cartesian directions: larger values mean the arm can move with relatively small joint velocities in any direction, while values near zero indicate a singular configuration where motion is constrained in some directions. This concept is about dexterity and isotropy of motion, not the robot’s physical size, the determinant of the inertia matrix, or sensor data quality.