Fuzzy logic based fuel flow selection system

A method of generating a fuel flow request signal for an engine, comprising:

• generating a plurality of fuel flow control signals from a plurality of control loops;
• assigning a level of authority to each of said fuel flow control signals based on fuzzy logic;
• combining each of said fuel control signals based on said levels of authority to provide a fuel flow request signal;
• computing said levels of authority based on a lookup table and a first algorithm, said lookup table having input and output qualifiers, said first algorithm being expressible as;
• LA k = ∑ i = 1 13 ⁢ ⁢ w i ⁢ X ik ∑ i = 1 13 ⁢ ⁢ w i ⁢ ⁢ k = 1 , 2 , 3
• where
• k corresponds to a column in said lookup table which correlates with each of said control loops,
• LAk is said level of authority for the kth control loop,
• i corresponds to a row in said lookup table,
• Xik corresponds to a corresponding said output qualifier at the ith row and the kth column in said lookup table, and
• wicorresponds to a corresponding said input qualifier for the ith row.

A fuel flow control system for use with an engine, including:

• a processor receptive to engine parameter signals, said processor processing said engine parameter signals;
• said processor generating a plurality of fuel flow control signals from a plurality of control loops;
• said processor assigning a level of authority to each of said fuel flow control signals based on fuzzy logic;
• said processor combining each of said fuel control signals based on said levels of authority to provide a fuel flow request signal;
• wherein said fuzzy logic comprises a plurality of rules and membership functions;
• wherein said rules comprise a lookup table having input and output qualifiers, said input qualifiers being defined by said membership functions;
• and
• wherein said membership functions include normalized loop errors.

A fuel flow control system for use with an engine, including:

• a processor receptive to engine parameter signals, said processor processing said engine parameter signals;
• said processor generating a plurality of fuel flow control signals from a plurality of control loops;
• said processor assigning a level of authority to each of said fuel flow control signals based on fuzzy logic;
• said processor combining each of said fuel control signals based on said levels of authority to provide a fuel flow request signal;
• said processor computing said levels of authority based on a lookup table and a first algorithm, said lookup table having input and output qualifiers, said first algorithm being expressible as;
• LA k = ∑ i = 1 13 ⁢ ⁢ w i ⁢ X ik ∑ i = 1 13 ⁢ ⁢ w i ⁢ ⁢ k = 1 , 2 , 3
• where
• k corresponds to a column in said lookup table which correlates with each of said control loops,
• LAk is said level of authority for the kth control loop,
• i corresponds to a row in said lookup table,
• Xik corresponds to a corresponding said output qualifier at the ith row and the kth column in said lookup table, and
• wi corresponds to a corresponding said input qualifier for the ith row.