Research On Mechanical And Control System Of Active Head Restraint

Passengers are very vulnerable to whiplash injury in rear-end collision which iscommon in road accidents. With the gradual deepening of study in this field byautomotive safety experts and increasing concerns of the community, many stateshave issued a series of regulations about the design of seat headrests, and car seatactive head restraints for whiplash injury protection are applied more and more widelyin many foreign vehicles. This fully illustrated the feasibility and necessity of activehead restraints in the protection of whiplash injury.Based on the study of literatures and relevant laws and regulations, this paperdeveloped a new active head restraint. It is characteristic of low cost, good effect andis easy to be popularized and applied. According to the collision prediction methodupon the acceleration signal of rear end collision, the active head restraint s controlstrategy is established. The main methods in use of this subject are computersimulation and test verification. Briefly, mechanical system and control system,production of prototype and test research of the active head restraint are completed inthis paper.A summary of the contents of this article is as follows: By analysis theadvantages and disadvantages of existing active headrest scheme, and combined withrelevant laws and regulations of headrests, the overall scheme of studying a collisionresponse type active head restraint based on the rear-end collision determination wasconfirmed. It designed the mechanical system of the active head restraint whichachieved the design objective of locking reliably and unlocking rapidly. It mainlyincludes mechanical design, pop displacement design and selection of theelectromagnet. In order to develop a control system of the active headrest, it studiedthe acceleration signal characteristics of rear-end collisions. On this basis, the controlalgorithm of the active head restraint is researched. And then the hardware design andsoftware design of the control system was completed. Several tests were conducted onthe active head restraint, including impact force testing experiment, high-speed videotest, oscillating weight experiment and rear sled test.The research results show that the control system of the active head restraint canexport trigger signal accurately and timely. The mechanical structure of the activehead restraint can be fully expanded within24ms. The forward movement of theactive head restraint is41mm, and the upward movement is44mm. To sum up, the active head restraint meets the design requirements of this article and has an effectiveprotection of whiplash injury.