GB2267953A

GB2267953A - Control system with plural manual control members.

Info

Publication number: GB2267953A
Application number: GB9212407A
Authority: GB
Inventors: J Paul Hodgson
Original assignee: British Aerospace PLC
Current assignee: BAE Systems PLC
Priority date: 1992-06-11
Filing date: 1992-06-11
Publication date: 1993-12-22
Also published as: GB9212407D0

Abstract

At least two manually operable control members provide a single output function to control an operating system eg. an aircraft flight control system, weapons firing system or hazardous manufacturing process. Each control member, eg flight control sidestick (10, 11), is moveable between an out-of-use, eg central, position and a range of in-use positions. Selection means detect movement of a control member (10, 11) from the out-of-use position to an in-use position and in response thereto connect the output function of that control member (10, 11) to the operating system irrespective of the position of any other control member. Thus an operator can be certain of being in control by engaging the out of-use position, even if momentarily, before continuing to operate the control member. The selection means may include microswitches 14, 15, flip- flop device 17 and coils 18, 19 in a relay 16. <IMAGE>

Description

A CONTROL SYSTEM This invention relates to control systems and in particular to a control system involving two or more manually operable control members, the output from only one of which is required at any given time.

Such control systems are known for example in aircraft cockpits for two pilots where each pilot will have a flight control sidestick of which only one may be in use at any given time. Weapons systems may have remote and local firing systems alternately operable; also certain hazardous manufacturing processes may have both local and remote safety override systems.

In aircraft flight control systems it is known to have both pilot control sticks mechanically linked and it is also known to have each control stick moveable entirely independently of the other and with logic circuitry summing the output functions of both control sticks to provide a single output control function to the aircraft flight controls. Priority of control in this case may be decided by push button selection. This method of control, where the push button selection system is not used, can lead to uncertainty as to which pilot is controlling the aircraft, also one pilot is unable to tell by feel how the other pilot is moving his control stick.

Where push button selection is used this requires the pilot to make a non instinctive movement, also the system requires the button to be held depressed for an extended period before priority of control is changed.

It is an object of the invention to provide a control system of the type described offering greater ease of operation and operator certainly as to whether his controlling movements on the control member are being transmitted to the function controlled.

According to the invention there is provided a control system including at least two manually operable control members for providing a single output function to control an operating system wherein each control member is moveable between a zero demand or out-of-use position and a range of control demand or in-use positions and the control system further includes selection means to detect movement of a control member from the out-of-use position to an in-use position and in response thereto to connect the output function of that control member to the operating system.

It is thus possible for an operator to be certain that his movements on the control member are being fed to the system under control by engaging the out-of-use position, even if momentarily, before continuing to operate the control member. Excessive or inadequate movements of another control member by an operator who has become incapacitated for some reason may thus be nullified in this way.

The control members may be aircraft flight control sticks.

The control system may include means to detect types of control member movement falling outside predetermined parameters, for example movements which are too rapid and/or which are nonsensical may be interpreted by logic control means. The movements may then be either ignored by the control system or may trigger some form of physical or audible signal or may automatically transfer control to another control member.

The selection means may comprise a switch which changes state in response to said movement of the control member from the out-of-use position to an in use position or may comprise a proximity detector operable in response to the control member moving further than a pre-determined distance from the out-of-use position.

The selection means may include logic switching means in combination with power relay means for controlling control functions in which transmitted power requires heavy duty switching means.

The invention will now be described by way of example with reference to the accompanying drawings of which:- Figure 1 is a schematic illustration of an aircraft cockpit and side control stick, and Figure 2 is a diagrammatic representation of a logic circuit according to the invention.

Referring to figure 1, a seat 1 is positioned beside a control console 2 upon which is mounted a pilot's sidestick 3 for controlling pitch and roll movements of an aircraft. A flexible gaiter 4 encloses a lower portion of the sidestick 3 and allows movement of the sidestick 3 about a universal joint (not shown) positioned within the console. The sidestick 3 may therefore be moved back and forth, from side to side and around in a circular movement. The sidestick 3 has a central out-of-use position equivalent to straight line flight of the aircraft. Whenever the sidestick 3 is moved in any direction from this central position such movement is detected by a microswitch (see figure 2) and the function of the sidestick in controlling the aircraft is either confirmed or transferred to that sidestick depending upon whether the other sidestick is in use at the time.

Referring to figure 2, two control members are shown 10, 11. Each has an angular position transducer 12, 13 and an "out of detent" microswitch 14, 15. Each angular position transducer 12, 13 is connected to an input terminal of a bi-stable relay 16 or equivalent device. Each microswitch 14, 15 is connected to an input terminal of a flip-flop device 17. Each output terminal of the flip-flop device 17 is connected to a coil 18, 19 in the relay 16 whereby to switch the relay 16 from one state to the other depending upon which input line is powered up by the flip flop 17.

The output from the relay comprises a control signal to an operating system (not shown) which is to be controlled by one or other of the control members 10, 11.

Each control member is shown with only a single degree of freedom but, for example, a pilot's flight control stick would have two degrees of freedom being rotatable about two mutually perpendicular axes. In this case the microswitch would activate upon movement of the control member about either rotational axis from the detent position.

Claims

1. According to the invention there is provided a control system including at least two manually operable control members for providing a single output function to control an operating system wherein each control member is moveable between an out-of-use position and a range of in-use positions and the control system further includes selection means to detect movement of a control member from the out-of-use position to an in-use position and in response thereto to connect the output function of that control member to the operating system.

2. A control system as in claim 1 in which the control members are aircraft flight control sticks.

3. A control system as in claim 1 or 2 including means to detect types of control movement falling outside pre-determined parameters.

4. A control system as in any preceding claim in which the selection means comprises a switch which changes state in response to movement of the control member from the out-of-use position to an in-use position.

5. A control system as in any of claims 1, 2 or 3 in which the selection means comprises a proximity detector operable in response to the control member moving further than a predetermined distance from the out-of-use position.

6. A control system as in any preceding claim in which the selection means includes logic switching means and power relay means.

7. A control system including at least two manually operable control members for providing a single output function to control an operating system substantially as herein described with reference to the accompanying drawings.