Control allocation deals with distributing the total virtual control input among the individual physical actuators in overactuated systems. We propose a new real-time solution for direct allocation problem, where a linear relationship exists between the virtual three-dimensional control vector and the actual constrained control inputs vector of a bigger size. The proposed procedure is based on zonotope properties and is suitable for on-line reconfiguration in case of actuators faults. The resulting vector of actual system inputs can be computed analogously to the determination of control in polyhedral Lyapunov function method.