Sensorless Friction and Gravity Compensation [Online]
IEEE RAS International Conference on Humanoid Robots (Humanoids 2014)

In this video we present a new controller for robots, called
Zero-Friction Zero-Gravity control. The controllers combine terms for
compensating the forces exerted by gravity, and the forces of friction
of motors and reductions. The consequence of applying this control to a
robot (a humanoid robot arm in this case) result in a free movement, as
if the robot were floating in space. Only the inertia drives the
movements by zeroing the forces of friction and gravity. This control,
when applied to an adequate robotic platform, could allow to simulate
gravity free conditions of movement. A slightly different version of
this controller, namely Low-Friction Zero-Gravity control, allows new
forms of human-robot interaction. This controller introduces an
attenuation variable for the friction compensation term, which makes a
smooth and easy interaction with the robot possible, whose movement
eventually stops due to the low friction. Experiments are performed
using 1 DoF of an arm of the humanoid robot Teo.

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