Variable gain synchrophasing

Claim 2

Apparatus, for synchrophasing aircraft engine propellers, comprising: a summer, for providing a first phase deviation signal indicative of the difference between measured relative propeller phase and preferred relative propeller phase; a gain stage, responsive to said first phase deviation signal, for providing a second phase deviation signal having a value equal to the product of the value of said first phase deviation signal and a variable gain, said gain varying according to the value of said first phase deviation signal; and a control stage, responsive to said second phase deviation signal, for adjusting the speed of one or more of the propellers according to a control law applied to said second phase deviation signal.

Claim 3

Apparatus, for synchrophasing aircraft engine propellers, according to claim 1, wherein said variable gain is a equal to a first constant predetermined value in response to said first phase deviation signal being less than a first gain change value, wherein said gain is equal to a second constant predetermined value in response to said first phase deviation signal being greater than a second gain change value, said second gain change value being greater than said first gain change value, and wherein said gain is equal to a third constant predetermined value in response to said first phase deviation signal being greater than or equal to said first gain change value and less than or equal to said second gain change value.

Claim 4

Apparatus, for synchrophasing aircraft engine propellers, according to claim 2, wherein said first and second constant predetermined values are equal.

Claim 5

Apparatus, for synchrophasing aircraft engine propellers, according to claim 3, wherein said third constant predetermined value is less than said first constant predetermined value.

Claim 6

Apparatus, for synchrophasing aircraft engine propellers, according to claim 4, wherein said first and second constant predetermined values equal one.

Claim 7

Apparatus, for synchrophasing aircraft engine propellers, according to claim 5, wherein said third constant predetermined value equals one fourth.

Claim 8

Apparatus, for synchrophasing aircraft engine propellers, according to claim 6, wherein said first gain change value is -2° and said second gain change value is 2°.

Claim 9

Apparatus, for synchrophasing aircraft engine propellers, according to claim 7, wherein said control law is KP+KI/s.

Claim 10

Apparatus, for synchrophasing aircraft engine propellers, according to claim 8, wherein KP equals 0.333 and KI equals 0.111.

Claim 11

Apparatus, for synchrophasing aircraft engine propellers, according to claim 9, wherein said summer, said gain stage, and said control stage are implemented as microprocessor software embedded in a ROM.

Claim 14

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 11, wherein said gain is determined by the steps of: setting said gain to a first constant predetermined value if the magnitude of said first phase deviation is less than a first gain change value; setting said gain to a second predetermined value if the magnitude of said first phase deviation is greater than a second gain change value, said second gain change value being greater than said first gain change value; and setting said gain to a third predetermined value if the magnitude of said first phase deviation is greater than or equal to said first gain change value and is less than or equal to said second gain change value.

Claim 15

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 12, wherein said first and second constant predetermined values are equal.

Claim 16

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 13, wherein said third constant predetermined value is less than said first constant predetermined value.

Claim 17

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 14, wherein said first and second constant predetermined values equal one.

Claim 18

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 15, wherein said third constant predetermined value equals one fourth.

Claim 19

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 16, wherein said first gain change value is -2° and said second gain change value is 2°.

Claim 20

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 17, wherein said control law is KP+KI/s.

Claim 21

A method for using an aircraft engine propeller synchrophasing system having a preferred relative phase signal input, a measured relative phase signal input, and provision for an adjustable gain, according to claim 18, wherein KP equals 0.333 and KI equals 0.111.