Transitioning a control system between changing state equations

A method of transitioning a control system of a vehicle, the method comprising;

• detecting a requested transition in the operation of the vehicle between one of a first range and a second range to the other of the first range and the second range;
• selecting at least one reference value and at least one state output value of a current set of state equations that describe the one of the first range and the second range in which the vehicle is currently operating in;
• selecting at least one reference value and at least one state output value of a target set of state equations that describe the one of the first range and the second range that the vehicle is transitioning into;
• multiplying a difference between the at least one reference value of the current set of state equations and the at least one reference value of the target set of state equations by a multiplier to define a reference product, and summing the reference product with the at least one reference value of the current set of state equations to define an adjusted reference value;
• multiplying a difference between the at least one state output value of the current set of state equations and the at least one state output value of the target set of state equations by the multiplier to define a state product, and summing the state product with the at least one state output value of the current set of state equations to define an adjusted state output value;
• comparing the adjusted reference value and the adjusted state output value to the at least one reference value and the at least one state output value of the target set of state equations respectively to determine if the adjusted reference value and the adjusted state output value are greater than, equal to or less than a pre-defined percentage of the at least one reference value and the at least one state output value of the target set of state equations respectively;
• and
• recalculating the adjusted reference value and the adjusted state output value when the adjusted reference value and the adjusted state output value are less than a pre-defined percentage of the at least one reference value and the at least one state output value of the target set of state equations respectively until the adjusted reference value and the adjusted state output value are equal to or greater than the pre-defined percentage of the at least one reference value and the at least one state output value of the target set of state equations respectively to smooth the requested change between the first range and the second range.