A New Tool for the Vibration Engineer

Significant progress could not have been made in the Sound Quality area without the invention and development of engineering tools. For the sound engineer, the binaural recording head is a primary example of one of those tools. The use of the binaural recording head was crucial to the development of the sound characterization process and has become an essential tool in the Sound Quality areas in Ford Motor Company. A similar tool, The Ford Vehicle Vibration Simulator, has been developed for the vibration engineer. The vehicle vibration simulator (VVS) is unique, consisting of vibration of the vehicle seat (6 degrees of freedom), steering wheel (4 DOF), vehicle floorpan section (1 DOF), and the brake or accelerator pedal (1 DOF). Many vibration test systems have been developed to study human response to vibration, especially for military and space applications. To our knowledge, this is the first multi-axis, fully integrated vibration test system to be used for automotive applications. Initially, the vibration simulator has been used to study vehicle ride and truck idle quality. Vibration time histories measured on different vehicles for a rough road surface and various engine idle conditions were used for playback on the vehicle simulator. Subjective impressions from human evaluators of vehicle ride and idle quality were correlated to objective measures derived from each vibration time history. The purpose of this paper is to provide a brief description of the simulator operation, present the detailed results of these studies, and discuss potential future applications for the VVS system.