Fly-by-wire lateral control system

In an aircraft, a fly-by-wire lateral control system, comprising:

• a symmetrical pair of lateral control surfaces, one on each wing of an aircraft;
• a plurality of two/one fail-operational, electrohydraulic actuators, each of which is drivingly connected to a separate lateral control surface, each said actuator comprising two hydraulic sections for redundant operation;
• four separate hydraulic pressure supplies;
• four separate electric control signal command channels;
• each said actuator including control means controlling each of its said two hydraulic sections with a dedicated separate hydraulic pressure supply, so that each of said four hydraulic pressure supplies is connected to a separate one of the four hydraulic sections, said control means also controlling all four of said electric-control signal command channels associated with each actuator, with two of said channels serving as active channels for a first of said actuators and as model channels for the second actuators, and with the remaining two channels serving as model channels for the first actuator and as active channels for the second actuator;
• and
• said control means for each actuator comprising:
• first means, associated with the two active channels for each actuator, and responsive to an electrical input signal supplied thereto, for independently and actively controlling the rate of operation of said two hydraulic sections of such actuator and for providing two rate indicative outputs, one for each hydraulic section;
• second means, associated with said two model channels for such actuator, and responsive to said electrical input signal supplied thereto, for modeling said first means and for providing two modeled rate indicative outputs, each modeled rate indicative output similar to the rate indicative output generated by said first means if said electrical input signal is applied to said first means through one of said two active channels;
• and
• third means for comparing the four rate indicative outputs generated from the first and second means and for providing a first failure signal if one of said four rate indicative outputs differs from the other three rate indicative outputs by a predetermined amount.

In an aircraft, a fly-by-wire lateral control system, comprising:

• a symmetrical pair of lateral control surfaces, one on each wing of an aircraft;
• a plurality of two/one fail-operational, electrohydraulic actuators, each of which is drivingly connected to a separate lateral control surface, each said actuator comprising two hydraulic sections for redundant operation;
• four separate hydraulic pressure supplies;
• four separate electric control signal command channels;
• each actuator including control means for controlling each of its said two hydraulic sections with a separate hydraulic pressure supply, so that each said hydraulic pressure supply is dedicated to a single hydraulic section, said control means also controlling all four of said electric control signal command channels associated with each actuator, with two of said channels serving as active channels for a first of said actuators and as model channels for the second actuator, and with the remaining two channels serving as model channels for the first actuator and active channels for the second actuator;
• and
• each said control means comprising:
• first means, associated with the active signal command channel for each actuator hydraulic section, and responsive to an electrical input signal supplied thereto, for actively controlling the rate of operation of its actuator hydraulic section, and for providing an actual actuator condition output;
• second means, associated with model channel for each actuator hydraulic section, and responsive to said electrical input signal supplied thereto, for modeling said first means and for providing a modeled actuator condition output, said modeled actuator condition output similar to the actuator condition output generated by said first means when said electrical input signal is applied to said active signal command channel;
• means, responsive to said actual actuator condition output and said modeled actuator condition output, for determining failure of one of said control signal command channels if said outputs vary by more than a predetermined amount, said determining means further providing an output indicative of which one of said active signal command channels has failed;
• and
• means, responsive to said determining means output indicative of an active signal command channel failure, for disconnecting said active signal command channel output from its associated controlling means and for connecting said model channel output to its associated controlling means, said disconnecting means, responsive to said determining means output indicative of model channel failure, for disconnecting said model channel.

In an aircraft, a fly-by-wire lateral control system, comprising:

• a symmetrical pair of lateral control surfaces, one on each wing of an aircraft;
• a plurality of two/one fail-operational, electrohydraulic actuators, each of which is drivingly connected to a separate lateral control surface, each said actuator comprising a first hydraulic section and a second hydraulic section for redundant operation;
• four separate hydraulic pressure supplies;
• four separate electric control signal command channels;
• each said actuator including control means controlling each of its said two hydraulic sections with a dedicated separate hydraulic pressure supply, so that each of said four hydraulic pressure supplies is connected to a separate one of the four hydraulic sections, said control means also controlling all four of said electric control signal command channels associated with each said actuator, with two of said channels serving as active channels for a first of said actuators and as model channels for the second actuator, and with the remaining two channels serving as model channels for the first actuator and as active channels for the second actuator;
• and
• each said control means comprising:
• first rate controlling means, having two inputs, for controlling rate of movement of the first hydraulic section of its actuator and providing a rate indicative output;
• second rate controlling means, having two inputs, for controlling rate of movement of the second hydraulic section of its actuator and providing a rate indicative output;
• first channel means, responsive to a first disabling control signal and to an electrical input signal, for normally applying a first channel positioning signal to one of said inputs of said first rate controlling means;
• second channel means, responsive to a second disabling control signal and to said electrical input signal, for normally transmitting a second channel positioning signal;
• second channel transfer means, responsive to a second channel transfer signal, for connecting said second channel positioning signal to the other of said inputs of said first rate controlling means;
• third channel means, responsive to a third disabling control signal and to said electrical input signal, for normally applying a third channel positioning signal to one of said inputs of said second rate controlling means;
• fourth channel means, responsive to a fourth disabling control signal and to said electrical input signal, for normally applying a fourth channel positioning signal to an output;
• fourth channel transfer means, responsive to a fourth channel transfer signal, for connecting said fourth channel positioning signal output to the other of said inputs of said second rate controlling means;
• and
• logic means for comparing the rate indicative outputs generated by said first and second rate controlling means and the second and fourth channel positioning signal outputs, each to the others, and for providing a disabling control signal when one of said outputs differs from the remaining three outputs by a predetermined amount;
• (a) when said first rate indicative output is said differing output, said logic means providing said first disabling control signal to said first channel means, said logic means providing said second channel transfer signal to said second channel transfer means, said logic means including means for treating said first rate indicative output as said second positioning signal output when said second channel transfer signal is applied to said second channel transfer means;
• (b) when said second channel means positioning signal output is said differing output, said logic means providing said second disabling control signal to said second channel means;
• (c) when said second rate indicative output is said differing output, said logic means providing said third disabling control signal to said third channel means, said logic means providing said fourth channel transfer signal to said fourth channel transfer means, said logic means including means for treating said second rate indicative output as said fourth positioning signal output when said fourth channel transfer signal is applied to said fourth channel transfer means;
• (d) when said fourth channel means positioning signal output is said differing output, said logic means providing said fourth disabling control signal to said fourth channel means;
• and
• said logic means further including means for comparing said remaining three outputs with each other and for providing further control signals in accordance with (a), (b), (c) and (d) when one of said remaining three outputs differs from the other two of said remaining three outputs by a predetermined amount.

In an aircraft, a fly-by-wire type lateral control system, comprising:

• a plurality of spoilers on each wing of the aircraft, each spoiler on each wing of the aircraft being operationally and symmetrically paired with a spoiler on the opposite wing of the aircraft and each such spoiler being operated by a single thread electrohydraulic actuator;
• at least one aileron on each wing of the aircraft which is symmetrically related to an aileron on the opposite wing of the aircraft, each said aileron being operated by a dual actuator;
• and
• control means including a plurality of independant hydraulic pressure supply lines and a plurality of independant electrical processing channels, for controlling the actuators for the spoilers and the ailerons such that a failure of a single hydraulic pressure line or a single electric control single processing channel will result in a loss of operation of a symmetrical pair of spoilers, but all ailerons will remain operational.

A fly-by-wire lateral control system for an aircraft, comprising:

• at least four independant pairs of spoilers symmetrically positioned on the wings of the aircraft;
• a pair of outboard ailerons symmetrically arranged on the wings of the aircraft;
• a pair of inboard ailerons symmetrically arranged on the wings of the aircraft;
• a single thread electrohydraulic servoactuator connected to each spoiler, for positioning the spoiler;
• a redundant electrohydraulic servoactuator connected to each aileron, for positioning the aileron, each servoactuator comprising two hydraulic sections;
• control means for controlling the spoilers and the ailerons, including a separate hydraulic pressure supply line and a separate electric control signal processing channel connected with the servoactuators for each pair of spoilers, and a separate pair of hydraulic pressure supply lines connected with each redundant servoactuator, and a separate pair of electric signal processing channels connected with each redundant servoactuator, each said channel to function as an active control channel for a section of its redundant servoactuator, said control means operating in response to hydraulic pressure supply line failures and/or electric signal processing channel failures to disable the single thread servoactuators for the spoilers symmetrically, in pairs, and to continue operation of each aileron after one hydraulic pressure supply line failure and/or one electric signal processing channel failure, and to continue operation of at least two of the ailerons following two hydraulic pressure supply line failures and/or two electric signal processing channel failures.