def PartialDynamicSystem(self, ieq, variable):
        """
        returns dynamical system blocks associated to output variable
        """
        if ieq == 0:
            # U1=0
            if variable == self.variables[0]:
                b1 = FunctionBlock(
                    self.physical_nodes[0].variable, self.max_torque, self.Tmax)
                b2 = Saturation(self.commands[0], self.throttle, 0, 1)
                b3 = Product(self.max_torque, self.throttle, variable)
                return[b1, b2, b3]
returns dynamical system blocks associated to output variable