FIELD OF THE INVENTION
The field of this invention is control signal interface in the aircraft avionics Human
Machine Interface (HMI) systems to provide command and control link between the
automatic flight control system of the aircraft and the pilot/copilot. The automatic
flight control system’s role is to maintain the aircraft stable in the air.
BACKGROUND OF THE INVENTION
The automatic flight control system of the aircraft comprises of Automatic Flight
Control Computer. The aircraft has avionics system installed the cockpit serving as a
Human Machine Interface between the Pilot/Copilot and automatic flight control
system. HMI front panel has Push buttons to perform the control and command
functions. HMI feeds the pilot selected controls to automatic flight control computer
for basic stabilization and control augmentation, auto-trim functions, engagement
and disengagement of autopilot modes.
SUMMARY OF PRESENT INVENTION
In accordance with one aspect of present invention is to provide a control and
command interface between the pilot and the automatic flight control system.
In accordance with second aspect of present invention is to provide a push
buttons/Bezel Keys based front panel with a minimal bounce time in a human
machine interface for the pilot.
In accordance with another aspect of present invention is to provide an interface to
convert the push button/Bezel key press event into digital control logic.
In accordance with yet another aspect of present invention is to provide a high
response optically coupled interface for conditioning and converting digital control
logic into aircraft discrete control logic.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: It shows the functional block diagram of the control signal generation.
DETAILED DESCRIPTION
The human machine interface (HMI) in the aircraft avionics system is used as a
control and display between the pilot/copilot and the control system/sensor of the
aircraft. The old cockpit design which was based on analog instruments to provide
the pilot with the information of aircraft’s critical parameters was complex in nature
and it was difficult for the pilot to maintain the situational awareness while monitoring
all the analog panels.
The latest glass cockpits utilize the HMI concept which provides the pilot with the
right information when needed and asked by the pilot. The HMI helps the pilot control
and stabilize the aircraft through the input given with help of buttons and knobs on
the HMI panel. Furthermore the HMI screen displays the aircrafts flight parameters
which can be monitored by the pilot.
The aircraft’s parameter information reaches the HMI system through the sensor and
then it is processed and conditioned by the modules inside the HMI system. The
processed and conditioned parameters are displayed over the front end of the HMI.
The pilot gives the stabilization, auto trim, pitch trim, roll trim and yaw trim commands
through the Bezel keys and push buttons to the flight control system which in turn
controls the aircraft as per the set value of the command.
The front panel of HMI module has push buttons/Bezel Keys. The TTL output of the
push buttons is fed to discrete generation module and converted to 28 V level for
sending the status signals to automatic flight control computer.
The solid state relay used in the discrete output generation module is having infrared
LED and MOSFET in it is used for the conversion. The relay MOSFET is controlled
by the LED light which gets on or off when energized through the 5V/0V digital logic
to give the output of the relay. The output is connected to Normally open terminal of
the relay output.
The opto-coupler gets energized when TTL 5V is applied at input in event of push
button press and is connected to 28V. The 28V/open signal is given to the flight
control computer where the automatic flight control system performs the control,
stabilization and trim function in the aircraft.

WE CLAIMS:-
Accordingly, the description of the present invention is to be considered as illustrative only and is for the purpose of teaching those skilled in the art of the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and exclusive use of all modifications which are within the scope of the appended claims is reserved. We Claim

1. The Human Machine Interface (HMI) control signal generation interface of the aircraft comprises, i) Ruggedized HMI front panel with Bezel Keys/Push Buttons and Active Matrix LCD ii) Push button control logic generation interface iii) Infrared Opto-coupler based control signal generation module to convert digital control logic into aircraft’s discrete logic level.

2. The control signal generation module as in the claim 1, is capable of interfacing any electronic modules of a system whether land based, military or airborne with 122 pin connector.

3. The push button control logic generation interface as in the claim 1, is capable of interfacing front end of any Human Machine Interface whether land based, military or airborne with a 50 pin connector.

4. The front panel as in the claim 1, is capable providing of 500,000 actuations of the push buttons with bounce time less than 6 milliseconds whether used in land based, military or airborne HMI system.

5. The control signal generation module as in the claim 1, is capable of interfacing any avionics system whether land based, military or airborne having 28Volt/Open discrete signal level as input.

6. The push button control logic generation interface as in the claim 1, is capable of interfacing backend of any Human Machine Interface whether land based, military or airborne having 5Volt/0Volt digital signal as input. ,TagSPECI:As per Annexure-II