GB2049595A - G-Force simulation system for an aircraft simulator - Google Patents

Abstract

A G-suit pressurised air supply comprises in series a mechanical filter (12), an ON/OFF valve (14), a pressure regulator (16), and an electrical-to-pressure transducer (18), whereby the suit pressure can be accurately and reliably controlled by an electrical signal applied to the transducer input (20). The transducer output is preferably applied to the suit through bias relay (30) and a volume booster (32), the latter receiving an input direct from the air supply. An emergency pressure relief valve may be included which operates in a fail safe mode. <IMAGE>

Description

SPECIFICATION G-force simulation system for an aircraft simulator This invention relates to a G - force simulation system for an aircraft simulator, having an improved pressurised air supply.

In order to provide some simulation of G - forces to a pilot in a simulator it is known to inflate either his suit or separate inflatable bags, which may be attached to him or placed between him and his seat, to produce more restraint on his harness. To provide simulation that is at all realistic it is necessary for the equipment to respond quickly and with consistency to an electrical control signal.

Previously proposed systems have tended to produce erratic results, with risk of injury to the trainee.

This invention provides an improved pressurised air supply for such use, and is defined in the appended claims.

The invention will be described by way of example with reference to the drawings, in which: Figure 1 shows in block form a system embodying this invention; and Figure 2 shows a modified system based on Figure 1.

Referring to Figure 1, the system 10 draws on a pressurised air supply of typically 60-70 psig. The air should be clean and dry to Defence Standard 16-8 and may be obtained from bottles or may be provided by a suitable oil-free compressor. The air is supplied to a mechanical filter 12 which removes any large particles of contaminant so that they do not block the valves subsequent to it. An ON/OFF control valve 14 is connected to the filter outlet, and a pressure regulator 16 is connected to the ON/OFF valve 14. The pressure regulator reduces the pressure in the line to a maximum of 15 psig.

From the pressure regulator 16 the air passes to a voltage-to-pressure tranducer 18 which operates in response to an electrical control signal at an input 20 to control the pressure at the transducer outlet in the range 15 to 3 psig. To make it possible to control down to low pressures (eg a range of 12 to 0 psig) a biasing relay may be connected to the transducer 18 to offset the signal applied thereto. The transducer 18 may for example be model No T5129 manufactured by Fairchild Industrial Products Division, 1501 Fairchild Drive, Winston-Salem, North Carolina 27105, United States of America.

Finally, a solenoid controlled valve 22 is included to ensure that the suit pressure can rapidly be relieved to atmosphere in an emergency. The valve 22 opens in response to a second control signal applied at an input 24. If the simulator emergency button is depressed the valve 22 is actuated, immediately reducing the pressure on the trainee. In fact, the valve 22 preferably operates in a fail-safe mode, so that if the power fails the pressure is relieved and the trainee is not subjected to increased G-effect.

The system illustrated in Figure 1 is found to be capable of operating reliably and safely. However, the system of Figure 2 provides certain improvements.

In Figure 2 the elements 12,14, 16 and 18 are the same as the correspondingly numbered elements in Figure 1. The output of the transducer 18 is now applied to a bias relay 30 which receives also the output of the pressure regulator 16. The bias relay 30 is designed to offset the graduated supply from transducer 18 so that absolute shut-off conditions can be achieved. In principle, the offset can achieve rates below zero.

To the output of the bias relay 30 is connected a volume booster 32. This receives also the input pressure, preferably after filtering by mechanical filter 12, through a line 34. The volume booster 32 operates proportionally to the output of the bias relay 30 and increases the volume of air supplied at the signal pressure, thus increasing the response rate to simulate tightturns which give quick increases in G and therefore require rapid inflation of the suit. A suitable volume booster is the 'Governaire', also manufactured by Fairchild Industrial Products Division.

The unit also responds to relieve pressure rapidly, thus adding to the effectiveness of the fail-safe relief valve fitted to the trainee's G suit, which is connected to the output of the volume booster 32.

The system illustrated in Figure 2 is found to be particularly effective. It provides a quick response and reduces the danger of injury to the trainee. The transducer 18 can be arranged to be computercon- trolled, thus giving great operational flexibility and in particular providing for a smooth transition over the required range of pressures. The system is inherently capable of being made very reliable.

1. AG - force simulation system for an aircraft simulator comprising an inflatable suit or bag for applying force to a trainee, a supply of clean and dry air, a mechanical filter connected to the air supply, a pressure regulator connected to the output of the mechanical filter, and an electrical-to-pressure transducer connected to the output of the pressure regulator, the suit or bag being connected to the output of the transducer.

2. A system according to claim 1, including biasing means in or connected to the output of the transducer for reducing the pressure by a predetermined amount or bias.

3. A system according to claim 1 or 2, including an ON/OFF control connected between the mechanical filter and the pressure regulator.

4. A system according to claim 1,2, or3, including an additional flow control device connected between the transducer and the suit or bag.

5. A system according to claim 4, in which the additional device comprises an emergency pressure reduction valve.

6. A system according to claim 4, in which the additional device comprises a volume booster unit having a second input connected to the air supply.

7. AG - force simulation system for an aircraft simulator, substantially as herein described with reference to Figure 1 ofthe drawings.

8. AG - force simulation system for an aircraft simulator, substantially as herein described with reference to Figure 2 of the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION G-force simulation system for an aircraft simulator This invention relates to a G - force simulation system for an aircraft simulator, having an improved pressurised air supply. In order to provide some simulation of G - forces to a pilot in a simulator it is known to inflate either his suit or separate inflatable bags, which may be attached to him or placed between him and his seat, to produce more restraint on his harness. To provide simulation that is at all realistic it is necessary for the equipment to respond quickly and with consistency to an electrical control signal. Previously proposed systems have tended to produce erratic results, with risk of injury to the trainee. This invention provides an improved pressurised air supply for such use, and is defined in the appended claims. The invention will be described by way of example with reference to the drawings, in which: Figure 1 shows in block form a system embodying this invention; and Figure 2 shows a modified system based on Figure 1. Referring to Figure 1, the system 10 draws on a pressurised air supply of typically 60-70 psig. The air should be clean and dry to Defence Standard 16-8 and may be obtained from bottles or may be provided by a suitable oil-free compressor. The air is supplied to a mechanical filter 12 which removes any large particles of contaminant so that they do not block the valves subsequent to it. An ON/OFF control valve 14 is connected to the filter outlet, and a pressure regulator 16 is connected to the ON/OFF valve 14. The pressure regulator reduces the pressure in the line to a maximum of 15 psig. From the pressure regulator 16 the air passes to a voltage-to-pressure tranducer 18 which operates in response to an electrical control signal at an input 20 to control the pressure at the transducer outlet in the range 15 to 3 psig. To make it possible to control down to low pressures (eg a range of 12 to 0 psig) a biasing relay may be connected to the transducer 18 to offset the signal applied thereto. The transducer 18 may for example be model No T5129 manufactured by Fairchild Industrial Products Division, 1501 Fairchild Drive, Winston-Salem, North Carolina 27105, United States of America. Finally, a solenoid controlled valve 22 is included to ensure that the suit pressure can rapidly be relieved to atmosphere in an emergency. The valve 22 opens in response to a second control signal applied at an input 24. If the simulator emergency button is depressed the valve 22 is actuated, immediately reducing the pressure on the trainee. In fact, the valve 22 preferably operates in a fail-safe mode, so that if the power fails the pressure is relieved and the trainee is not subjected to increased G-effect. The system illustrated in Figure 1 is found to be capable of operating reliably and safely. However, the system of Figure 2 provides certain improvements. In Figure 2 the elements 12,14, 16 and 18 are the same as the correspondingly numbered elements in Figure 1. The output of the transducer 18 is now applied to a bias relay 30 which receives also the output of the pressure regulator 16. The bias relay 30 is designed to offset the graduated supply from transducer 18 so that absolute shut-off conditions can be achieved. In principle, the offset can achieve rates below zero. To the output of the bias relay 30 is connected a volume booster 32. This receives also the input pressure, preferably after filtering by mechanical filter 12, through a line 34. The volume booster 32 operates proportionally to the output of the bias relay 30 and increases the volume of air supplied at the signal pressure, thus increasing the response rate to simulate tightturns which give quick increases in G and therefore require rapid inflation of the suit. A suitable volume booster is the 'Governaire', also manufactured by Fairchild Industrial Products Division. The unit also responds to relieve pressure rapidly, thus adding to the effectiveness of the fail-safe relief valve fitted to the trainee's G suit, which is connected to the output of the volume booster 32. The system illustrated in Figure 2 is found to be particularly effective. It provides a quick response and reduces the danger of injury to the trainee. The transducer 18 can be arranged to be computercon- trolled, thus giving great operational flexibility and in particular providing for a smooth transition over the required range of pressures. The system is inherently capable of being made very reliable. CLAIMS

1. AG - force simulation system for an aircraft simulator comprising an inflatable suit or bag for applying force to a trainee, a supply of clean and dry air, a mechanical filter connected to the air supply, a pressure regulator connected to the output of the mechanical filter, and an electrical-to-pressure transducer connected to the output of the pressure regulator, the suit or bag being connected to the output of the transducer.

2. A system according to claim 1, including biasing means in or connected to the output of the transducer for reducing the pressure by a predetermined amount or bias.

3. A system according to claim 1 or 2, including an ON/OFF control connected between the mechanical filter and the pressure regulator.

4. A system according to claim 1,2, or3, including an additional flow control device connected between the transducer and the suit or bag.

5. A system according to claim 4, in which the additional device comprises an emergency pressure reduction valve.

6. A system according to claim 4, in which the additional device comprises a volume booster unit having a second input connected to the air supply.

7. AG - force simulation system for an aircraft simulator, substantially as herein described with reference to Figure 1 ofthe drawings.

8. AG - force simulation system for an aircraft simulator, substantially as herein described with reference to Figure 2 of the drawings.