"I still got a long way to go, " said the New York City computer network specialist who had a stroke two days before his 40th birthday. "The robot really put a lot of muscle tone back in my arm.

When two-arm robot is equipped with force sensor, the effective stiffness of the end - effector play an important role in the system stability.

For the two-bar robot arm, we focus merely the whole kinetic energy at horizontal condition, and neglect the change of potential energy due to the bending deflection of the robot arm.