Patent ID: 7908111

Claim:
A sensor of position and speed of a movable part that can move along at least one measurement direction, the sensor comprising: at least one excitation inductor ( 10 ) suitable for inducing a magnetic excitation field as a function of an excitation current or voltage of the inductor, at least one target ( 12 ) made of conducting or magnetic material suitable for modifying the magnetic excitation field as a function of a position of the target, the target being secured to the movable part, at least one first transducer ( 14 ) suitable for transforming the magnetic excitation field modified by the target into an electrical measurement signal, and a first estimator ( 38 ) able to estimate, on completion of an observation period T obs , the position and speed of the target on the basis of N samples of the electrical measurement signal and of N samples of the excitation current and voltage, these samples being taken during the observation period T obs and N being an integer greater than two, wherein the estimator, using a model of displacement of the target during the observation period T obs , is able to establish the estimate of the position and of the speed of the movable part as a function of the model of displacement of the target during the observation period T obs , the model of displacement relating the position of the target at an instant t included in the observation period T obs to at least the position and the speed of the movable part to be estimated, in which the displacement model is defined by the following relation: X ⁡ ( t ) = g [ X ⁡ ( 0 ) , ∂ X ∂ t ⁢ ( 0 ) , … ⁢ ⁢ ∂ i ⁢ X ∂ t i ⁢ ( 0 ) , t ] ⁢ ⁢ t ∈ [ - T obs , 0 ] ( 5 ) where: X(t) is the position of the target along the measurement direction at the instant t belonging to the observation period [−T obs ; 0]; g is the displacement model; X ⁡ ( 0 ) , ∂ X ∂ t ⁢ ( 0 ) , … ⁢ ⁢ ∂ i ⁢ X ∂ t i ⁢ ( 0 ) correspond respectively to the position, the speed, the second derivative, . . . , the i th derivative of the position at the instant t=0, at the end of the observation period, the position and the speed corresponding, respectively, to the position and to the speed of the target to be estimated.