Friction force
TAU = friction(ROBOT,QD) TAU = friction(L,QD)
Link object
SerialLink object
vector of size (1xN) where N is the number of joints of the robot.
TAU = friction(L,QD)
is the joint friction force/torque for link velocity QD.
TAU = friction(ROBOT,QD)
is the vector of joint friction forces/torques for the
robot moving with joint velocities QD.
The friction model includes: - viscous friction which is linear with velocity;
- Coulomb friction which is proportional to sign(QD).
Friction values are referred to the motor, not the load.
Viscous friction is scale d up by G^2.
Coulomb friction is scaled up by G.
The sign of the gear ratio is used to determine the appropriate Coulomb friction value in the non-symmetric case.
[1] Robotics, Vision & Control, Chap 7, P. Corke, Springer 2011.