  Based on a mesoscopic theory we investigate the non-equilibrium dynamics of a
sheared nematic liquid, with the control parameter being the shear stress
$\sigma_{\mathrm{xy}}$ (rather than the usual shear rate, $\dot\gamma$). To
this end we supplement the equations of motion for the orientational order
parameters by an equation for $\dot\gamma$, which then becomes time-dependent.
Shearing the system from an isotropic state, the stress- controlled flow
properties turn out to be essentially identical to those at fixed $\dot\gamma$.
Pronounced differences when the equilibrium state is nematic. Here, shearing at
controlled $\dot\gamma$ yields several non-equilibrium transitions between
different dynamic states, including chaotic regimes. The corresponding
stress-controlled system has only one transition from a regular periodic into a
stationary (shear-aligned) state. The position of this transition in the
$\sigma_{\mathrm{xy}}$-$\dot\gamma$ plane turns out to be tunable by the delay
time entering our control scheme for $\sigma_{\mathrm{xy}}$. Moreover, a sudden
change of the control method can {\it stabilize} the chaotic states appearing
at fixed $\dot\gamma$.
