Abstract: The invention relates to a system for estimating at least one characteristic of a motor vehicle suspension, whereby said suspension or each suspension connects a motor vehicle wheel to the body shell thereof. The inventive system comprises means (12, 14) for acquiring vertical accelerations experienced by the wheel and body shell in a reference system of the vehicle and means (26) for calculating the at least one characteristic of the suspension as a function of the vertical accelerations acquired from the wheel and the body shell.

Abstract: The invention concerns a device for measuring the rotational speed of a vehicle wheel, comprising a housing (22), a printed circuit board (32) accommodated in the housing and an encoder cell (38) mounted on the printed circuit board and adapted to measure electromagnetic field variations. The device comprises at least one accelerometer (44;46) mounted on the printed circuit board (32) for measuring an acceleration along a first predetermined axis. The accelerometer may be mounted inclined relative to the plane of the printed circuit board.

Abstract: A method for evaluating instantaneous frequency of a mechanical excitation exerted on a motor vehicle wheel by the uneven surface of a road, based on measurements of observable parameters such as those related to the instantaneous height of the chassis and/or the wheel of the vehicle. The method includes a filtering procedure producing successive estimates of the instantaneous height of the chassis and of the wheel, a lag extracting procedure, producing an estimated value of the time lag between the height estimations, and a frequency estimating procedure, producing the desired evaluation of the frequency based on the estimated time lag value.

Abstract: A method for evaluating instantaneous frequency of a mechanical excitation exerted on a motor vehicle wheel by the uneven surface of a road, based on measurements of observable parameters such as those related to the instantaneous height of the chassis and/or the wheel of the vehicle. The method includes a filtering procedure producing successive estimates of the instantaneous height of the chassis and of the wheel, a lag extracting procedure, producing an estimated value of the time lag between the height estimations, and a frequency estimating procedure, producing the desired evaluation of the frequency based on the estimated time lag value.