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Semi-Active Damped Seating Technology for the EFV
Navy SBIR 2006.2 - Topic N06-103 MARCOR - Mr. Paul Lambert - [email protected] Opens: June 14, 2006 - Closes: July 14, 2006 N06-103 TITLE: Semi-Active Damped Seating Technology for the EFV TECHNOLOGY AREAS: Ground/Sea Vehicles, Human Systems ACQUISITION PROGRAM: DRPM Advanced Amphibious Assault ACAT-1 OBJECTIVE: Develop a suspended seating system which integrates semi-active shock and vibration mitigating technology into the existing EFV (Expeditionary Fighting Vehicle) seating positions. The system should be effective during both land and sea operations. The seat must fit within the current EFV structural constraints and not affect vehicle performance or interfere with crew duties. DESCRIPTION: The Marine Corps EFV is a 78,000 lb. armored and tracked troop carrier designed to operate over harsh off-road terrain and in oceans and rivers. It is capable of much higher speeds on water than its predecessors. Increased speed has lead to high shock loads being transmitted to the occupants when the vehicle is operated in high sea states, particularly in the forward seating positions for the driver and troopcrew commander. In addition to sea operations, the seat system must be capable during land operations to provide shock mitigation when the vehicle is traversing rough terrain. While the EFV is equipped with a pneumatic suspension system, the seating system must provide additional shock isolation during high impact events as well as providing useful isolation from lower amplitude vibration that is transmitted through the suspension and hull. This operating environment has created a never addressed before situation. Current seating designs are very effective for land operations or for waterborne operations but not for both, especially with the amplitudes felt in the EFV. An original and innovative solution to the seat system design is required. The seating system must be capable of compensating for variations in operator mass ranging from 5th to 95th percentile USMC personnel without user intervention or adjustment. The semi-active damper must be capable of providing sufficient dynamic range to prevent harsh contact with the end of travel stops during operations in extreme sea states or over rough terrain as well as providing good vibration isolation when operating over smooth roads or calm seas. ISO 2631 Part 5 "Mechanical vibration and shock-Evaluation of human exposure to whole-body vibration" will be used as the metric to determine effectiveness of the suspension system. This standard defines a shock "dose" which is transmitted into the seat occupant, a lower dose number indicating more effective shock mitigation. The seating system must be capable of responding in real time to changing sea states or road conditions without user intervention. The vehicle operator must be focused on the task of controlling the vehicle and cannot be expected to change or adjust suspension settings when the sea state changes. In addition the possibility of an unexpected or "rogue" wave must be detected and handled in real time by the suspension system. The damper must also provide a useable default mode in the case of system failure. Ideally an intermediate setting would be provided which allows the damper to continue to function as a passive damper. Power draw must be kept to a minimum and use only the available on board 24VDC power bus. Any hydraulic or pneumatic systems must be self-contained within the seat assembly and powered from the DC bus. The Seating system must also be affordable, easily maintainable, and operate reliably over extreme temperature ranges (-40 to +145 degrees F). The seating system must also be capable of withstanding long-term exposure to sea water, mud, dust, sand, and debris without significant degradation. PHASE I: Investigate current EFV seating design and performance; to include feasibility of incorporation of semi-active damping controlled seats. Develop overall system design to include specification of technological approach. Computer modeling and simulation should be used to predict performance benefits using shock input data from the EFV hull as the forcing function. Based on the information developed by the end of Phase 1, propose one or more semi-active seating design concepts. Include estimated prototype and production costs, space claim estimates, estimated performance improvements, estimated weight and power requirements. PHASE II: Down-select to one or two seat design concepts. Develop and demonstrate a prototype system in a realistic environment. Conduct testing to prove feasibility over extended operating conditions. Refine and re-test the seat or seats in order to further mature the technology and quantify the benefits. PHASE III: Support incorporation of the semi-active seating technology into prototype SDD and/or LRIP vehicles and support further maturation of the design. Transition the design to a full production capable version. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This system could be used in a broad range of military and civilian applications including seating for commercial boats, heavy equipment, trucking or any vehicle with either an extremely stiff or no suspension system. The system would mitigate injurious or debilitating effects caused by chronic exposure to severe and repeated mechanical shock. REFERENCES: KEYWORDS: Semi-active, seat, ride quality, shock, vibration TPOC: Craig Harvey
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