This provides ease in the outer-loop controller
design since the controller only has to deal with a linear system.
Although it is possible to employ SLMC for nonlinear
systems, the inner-loop torque linearization is advantageous in
the sense that it allows smaller controller gains to be used in
the SLMC controller. Hence, excessive control switching activities
(chattering), which may cause mechanical resonance,
can be relaxed. With the inner-loop torque linearization, the
electromechanical governing equation of the machine can be
simplified and written as