MyRoboPath
kinematics17 min readUpdated 2026-03-14Advanced

The Manipulator Jacobian: Velocities, Static Forces & Singularities

Relate joint angular velocities to end-effector Cartesian velocities, calculate Yoshikawa manipulability ellipsoids, and analyze boundary and interior kinematic singularities.

Dr. Soraya Al-Mansoor
Dr. Soraya Al-Mansoor
Professor of Robotics & Nonlinear Control

Key Engineering Takeaways

  • The Geometric Jacobian maps joint velocities to end-effector twists: V = [v, w]ᵀ = J(q) · q̇.
  • By principle of virtual work, static joint torques required to exert end-effector wrench F are: τ = J(q)ᵀ · F.
  • At singular configurations, the Jacobian loses rank (det(J)=0), meaning the robot loses the ability to move in one or more Cartesian directions.
Prerequisites
  • Partial derivatives
  • Forward Kinematics

Formulating the Geometric Jacobian J(q)

The Jacobian is a $6 \ imes n$ matrix where the top 3 rows map to linear velocity $\mathbf{v}$ and the bottom 3 rows map to angular velocity $\oldsymbol{\omega}$.
Tags:#Jacobian#Singularities#Manipulability#Statics#Velocities#Robotic Arm