Field of the Invention The present invention relates to an active damping system and, more particularly but not exclusively, to an active seat damping system for a military vehicle, aircraft or water vessel.

Background of the Invention

It has been proposed to provide seats which have suspension so as to reduce force transferred from a vehicle to an occupant of the vehicle. However, the applicant has identified that existing, systems do not account for occupants having different weight, particularly those having weight at either extreme. The applicant has also identified that existing systems do not adapt to changes in an occupant's clothing, or changes in the weight of items carried by the occupant while sitting in a seat of the vehicle. In the event of large or explosive forces as may be experienced in the event of the detonation of an improvised explosive device or in the ejection of seats from an aircraft, insufficient damping may cause bottoming out of the suspension system, and excessive damping may result in insufficient travel to reduce the force being transferred to the occupant.

Examples of the invention seek to solve, or at least ameliorate, one or more disadvantages of previous occupant support damping systems. Summary of the Invention

In accordance with one aspect of the present invention, there is provided a seat damping system including a seat mounted to a structure of a vehicle/aircraft watercraft for seating an occupant of the velricle/aircraft/watercraft, the seat being mounted to the structure in an arrangement adapted such that the seat is able to move relative to the structure in a predetermined event, an adjustable damper for damping movement of the seat relative to the structure, a controller for controlling adjustment of the damper, and a sensor for sensing a weight borne by the seat, wherein the controller adjusts the damper according to the weight sensed by the sensor such that in the predetermined event movement of the seat relative to the structure will be dampened according to the weight borne by the seat.

Preferably, the seat is mounted on a rail fixed to the structure of the vehicle/aircraft watercraft such that the seat is able to slide along the rail. Preferably, the seat damping system includes a pre-tensioning device acting between the structure and the seat to prevent movement of the seat under gravity or normal motion of the vehicle/aircraft/watercraft. More preferably, the pre-tensioning device is elastic. Even more preferably, the pre-tensioning device is pre-tenskmed to a predetermined value according to a weight of the occupant, a weight of the seat and/or weight of seat hardware.

Preferably, the predetermined event is acceleration of the seat beyond a predetermined ^' threshold. More preferably, the predetermined event is the vehicle/aircraft/watercraft experiencing acceleration caused by an explosion.

In a preferred form, the system includes a plurality of seats, each seat has a dedicated damper, a dedicated sensor, and a dedicated controller for measuring the weight sensed by the dedicated sensor and adjusting the dedicated damper according to the weight sensed by the dedicated sensor.

Preferably, each dedicated controller is in the form of an on-board controller mounted to the respective seat. More preferably, the on-board controller is adapted to re- measure the weight sensed by the sensor and to update the damper at preset intervals. It is preferred that the seat damping system includes an accelerometer to measure and account for acceleration of the vehicle/aircraft/watercraft in measuring weight for each t seat.

Preferably, the on-board controllers are powered by an electrical system of the vehicle/aircraft/watercraft. More preferably, the on-board controllers are coupled to a battery back-up for power supply in the event of a failure of the electrical system.

In a preferred fonn, the on-board controllers communicate over a CAN network to allow calibration, setting, downloads, diagnostics, and/or radio interface. Preferably, the seat damping system includes a master driver controller in communication with the on-board controllers, wherein the master driver controller is adapted to identify which seats are occupied, which seats have been triggered and/or which seats have adjusted according to the weight sensed by the respective sensor. More preferably, the seat damping system displays to a driver of the vehicle/aircraft watercraft a status of each seat of the vehicle/aircraft/watercraft.

Preferably, the seat damping system controls a rate of acceleration of each seat to reduce a peak force transferred from the structure of the vehicle/aircraft/watercraft to the occupant of the seat. More preferably, the seat damping system controls a rebound rate of the seat at a different level to said rate of acceleration.

In accordance with another aspect of the present invention, there is provided a military vehicle/aircraft/watercraft including a seat damping system as described above. In accordance with yet another aspect of the present invention, there is provided an occupant support damping system including an occupant support mounted to a structure for supporting an occupant of the structure, the occupant support being mounted to the structure in an arrangement adapted such that the occupant support is able to move relative to the structure in a predetermined event, an adjustable damper for damping movement of the occupant support relative to the structure, a controller for controlling adjustment of the damper, and a sensor for sensing a weight borne by the occupant support, wherein the controller adjusts the damper according to the weight sensed by the sensor such that in the predetermined event movement of the occupant support relative to the structure will be dampened according to the weight borne by the occupant support. Preferably, the structure is a structure of a vehicle/aircrafVwatercraft.

It is preferred that the occupant support is a seat or a bed.

Preferably, the damper is able to actively dampen in a plurality of directions, from the set including vertical, lateral and longitudinal mutually perpendicular axes, and rotational directions.

Preferably, the damper is in the form of a fluid damper, an electro-rheostatic damper, a damper using magneto-restrictive fluid, or a damper using a clutch drum with adjustable clutch plates.

In a preferred form, the. damping system is in communication with a CAN network.

Brief Description of the Drawings

The invention is described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic sketch of a seat damping system in accordance with an example of the present invention; and

Figure 2 is a diagrammatic sketch of a floor plan of a vehicle provided with a seat damping system in accordance with an example of the present invention. Detailed Description

Advantageously, examples of the present invention provide a seat damping system which is able to adapt a level of damping of the seat to the weight borne by the damper. In particular, the level of damping may be automatically adjusted to be tailored to the weight of the occupant of the seat, the weight of the seat itself, and the weight of any additional hardware of the seat. As the weight is measured by a sensor, the level of damping also takes into account clothes and any other items on the person of the occupant and being borne by the seat. Although examples of the invention are commonly referred to as being seat damping systems, it will also be appreciated that the invention also applies to other types of occupant supports such as beds, etc.

More specifically, with reference to Figure 1 of the drawings, there is provided a seat damping system 10 including a seat 12 mounted to a structure 14 of a vehicle/aircraft/watercraft 16 for seating an occupant of the vehicle/aircraft watercraft 16. The seat 12 is mounted to the structure 14 in an arrangement adapted such that the seat 12 is able to move relative to the structure 14 in a predetermined event. In the examples shown, the structure 14 is a mount of the vehicle/aircraft/watercraft 16, however it will be appreciated that any structurally sound component of the vehicle/aircraft/watercraft 16 such as a wall, floor or chassis member may form a suitable structural component to which the seat may be mounted, either directly or indirectly. The seat damping system 10 also includes an adjustable damper 18 for damping movement of the seat 12 relative to the structure 14, a controller 20 for controlling adjustment of the damper 18, and a sensor 22 for sensing a weight borne by the seat 12. The controller 20 adjusts the damper 18 according to the weight sensed by the sensor 22 such that in the predetermined event, movement of the seat 12 relative to the structure 14 will be dampened according to the weight borne by the seat 12.

Although appreciated by those skilled in the art that the present invention is equally applicable to aircraft (for example ejector seats of aircraft) and to watercraft, for the sake of brevity the remainder of the detailed description will simply refer to "vehicle". As shown in Figure 1, the seat 12 may be mounted on a rail 24 fixed to the structure 14 of the vehicle 16 such that the seat 12 is able to slide along the rail 24. For this purpose, the seat 12 may be fitted with a slide/guide 26 which fits over the rail 24 so as to slide along the rail 24. For the sake of stability, the seat 12 may be provided with a pair of guides 26 to guide the seat 12 along the rail 24.

The seat damping system 10 may include a pre-tensioning device 28 acting between the structure 14 and the seat 12 to prevent movement of the seat 12 under gravity or normal motion of the vehicle 16. The term normal motion is used in the sense of normal driving of the vehicle, and any other normal motion of the vehicle, in contrast to extreme acceleration of the vehicle caused by explosion of an improvised explosive device or the like. The pre-tensioning device 28 may be elastic, and may be pre-tensioned to a predetermined value according to a weight of the occupant, a weight of the seat 12 and a weight of any additional seat hardware supported by the damper 18. The predetermined event may be acceleration of the seat 12 beyond a predetermined threshold and, more specifically, extreme acceleration of the vehicle 16 caused by an explosion.

The sensor 22 may be in the form of a load sensor embedded in a seat base 30 of the seat 12, as shown in Figure 1. The sensor 22 may be coupled to the controller 20 by way of a communication wire, and the controller 20 may be in communication with the adjustable damper 18 by way of further wire. Wiring may also be used to connect the controller 20 to a central controller, or to controllers of other seats in the vehicle 16. With reference to Figure 2, in one example, there is provided a vehicle 1 with a seat damping system 10 having a plurality of seats 12, each seat 12 having a dedicated damper 18, a dedicated sensor 22, and a dedicated controller 20 for measuring the weight sensed by the dedicated sensor 22 and adjusting the dedicated damper 18 according to the weight sensed by the dedicated sensor 22. Each dedicated controller 20 may be in the form of an on-board controller (OBC) 20 mounted to the respective seat 12. The on-board controller 20 may be adapted to re-measure the weight sensed by the sensor 22 and to update the damper 18 at preset intervals. Each of the seats 12 in the vehicle 16 may be generally the same as the seat 12 shown in Figure 1.

The seat damping system 10 may include an accelerometer to measure and account for acceleration of the vehicle 16 in measuring weight for each seat 12. This may be useful in preventing distorted measurements when the vehicle 16 itself is subjected to acceleration.

The on-board controllers 20 may be powered by an electrical system of the vehicle 16. As shown in Figure 2, the on-board controllers 20 are connected in series in a loop. As the vehicle wiring goes all the way around in a loop, this allows for continued power and CAN communication from either direction in the event that a wire or connection is faulty thus making the system more robust and fail safe. By CAN, it will be understood that this refers to a Controller Area Network which is a networking standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer.

The on-board controllers 20 may be coupled to a battery back-up for power supply in the event of a failure of the electrical system. The on-board controllers 20 may communicate over a CAN network to allow calibration, setting, downloads, diagnostics, and/or radio interface.

As shown in Figures 1 and 2, the seat damping system 10 may also include a master driver controller 32 in communication with the on-board controllers 20. The master driver controller 20 may be adapted to identify which seats 12 are occupied, which seats 12 have been triggered and/or which seats 12 have adjusted according to the weight sensed by the respective sensor 22. The master driver controlle 32 may also be used to display to a driver of the vehicle 16 a status of each seat of the vehicle 16. The seat damping system 10 may control a rate of acceleration of each seat 12 to reduce a peak force transferred from the structure 14 of the vehicle 16 to the occupant of the seat 12, In one form, the seat damping system 10 may control a rebound rate of the seat 12 at a different level to said rate of acceleration.

Examples

The Active Seat Damping System (ASDS) is a damping system for occupant seating that pre-conditions the seat according to the weight of the occupant, by setting a damping function that controls the seat reaction to large or explosive G-Forces. An example of use is in armed forces troop seating in armoured personnel carriers that are subjected to Improvised Explosive Device (IED) detonation or in ejection seats in aircraft or in occupant seats in high speed marine rescue/military vessels to name but a few.

Basically;

- the seat is attached to the wall of the vehicle/vessel (or to the sled in an ejection seat), or can be attached to the roof or to the floor.

- the seat is located on rails that enable it to slide up and down freely with additional allowance for sideways movement if required

- The seat is located to prevent movement under gravity or normal motion by the use of a pre-tensioning device that is elastic in nature. This device is pre-tensioned to a pre-determined value for a pre-determined occupant weight + seat + seat hardware weight (based on the seat application and use).

- The ASDS system is used to adjust an additional motion damper(s), electronically, to cater for variations in occupant weight between a low percentile person to a high percentile person

- The ASDS adjusts its damping settings by measuring the weight of the occupant, via a strain gauge or load sensor (examples could include these being mounted in the seat bottom cushion or in the pre-tensioning device)

- The damping function can be set differently for the upward, downward, or sideways motion of the seat according to the G-Forces experienced

- In one variation of the design, the seat would have its own On Board Controller (OBC) that measures and adjusts the seat settings accordingly. This controller would contain proprietary electronics and software and would be powered by the vehicle electrical system and may or may not have a battery back up of some type (example: battery, capacitor, etc). This controller could communicate via CAN messaging over the power cable or via dedicated communication ports that would allow calibration, setting, downloads, diagnostics, radio interface, blue tooth and other such functions found on CAN products in the Automotive, Marine, Mining and Defence Industries (as an example).

- In one variation of the design, there would also be a Master Driver Controller (MDC) that would be located near the driver or vehicle/vessel controller that would identify,, which seats are occupied, which seats have been triggered and need replacing, which seats have a fault, which seats have learnt to their occupant weight and are ready as examples. This could be communicated via a display, Multi-colour LED's, radio link etc

- the seats would be connected to power and can be interconnected via CAN as a separate wire, or can also be linked via CAN-Over-Power, radio links, Bluetooth or otherwise as examples

In alternative examples, the base could also have a slide and ASDS device that allows it to slide separate to the seat back. In some applications, this could be in addition to the Slide+Pre-tension+ASDS for the seat back or instead of this arrangement

Example of Use - OBC base system

Active Seat Damping System - ASDS Using the example of an armoured personnel carrier, the following is offered.

- Occupants enter vehicle and sit in seats

- Ignition is turned on and engine is started (thus providing power to seat and ASDS system)

- ASDS OBC turns on and measures occupant weight

- OBC pre-sets damping system to match occupant weight

- Vehicle drives away - OBC re-measures weight at pte-set intervals and updates ASDS setting(to allow for occupant removal of gear, or late arrivals, or occupants changing seats while vehicle is in motion etc). OBC can allow for vehicle motion causing false readings via optional Accelerometer

- Vehicle encounters IED and subjected to large G- forces.

- ASDS controls the rate of acceleration of the seat to reduce G-Fovce transfer to occupant

- ASDS can also control rebound rate at a different level

- OBC sets a fault light that the system has been triggered and needs to be replaced (the seats have sacrificial devices in them which fail in an IED event and hence the seat needs to be replaced. These are not always visually detected and the seat may need to be disassembled to determine if this has been triggered or not.

- Note, if the ASDS system also has a side motion control this would work similarly

Example of Use - Full feature system

Active Seat Damping System - ASDS

Using the example of an annoured personnel carrier, the following is offered.

- Occupants enter vehicle and sit in seats

- Ignition is turned on and engine is started (thus providing power to seat and ASDS system)

- ASDS OBC turns on and measures occupant weight

- OBC pre-sets damping system to match occupant weight

- MDC displays to driver the status of each seat, which seats are occupied and other information. The MDC can be set up to know which OBC's are connected and display seat numbers and locations.

- Vehicle drives away

- OBC re-measures weight at pie-set intervals and updates ASDS setting(to allow for occupant removal of gear, or late arrivals, or occupants changing seats while vehicle is in motion etc). OBC can allow for vehicle motion causing false readings - Π - via optional Accelerometer. OBC and MDC regularly communicate via CAN and update driver accordingly

- Vehicle encounters IED and subjected to large G-forces.

- ASDS controls the rate of acceleration of the seat to reduce G-Force transfer to occupant

- ASDS can also control rebound rate at a different level

- OBC sets a fault light that the system has been triggered and needs to be replaced (the seats have sacrificial devices in them which fail in an IED event and hence the seat needs to be replaced. This is repeated at the MDC, the MDC can also tell the repairers which seats need to be replaced. When the seat is replaced, the repairer

"learns" the new seat to that location in the display software.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in fonn and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.