Patent ID: 8261545

Claim:
An electric power actuator, said actuator ( 1 ) comprising: a control unit ( 2 ) which receives an electric control signal and which converts this electric control signal into a set point for an electric motor ( 4 ); said electric motor ( 4 ) which drives a pump ( 5 ) in accordance with said set point received from said control unit ( 2 ); said pump ( 5 ) which generates hydraulic power for moving a hydraulic jack ( 8 ); said hydraulic jack ( 8 ) which includes two chambers ( 9 , 10 ) likely to be fed by said pump ( 5 ), and which generates the strain of the actuator ( 1 ); at least one pressure relief valve ( 11 ) for limiting the load generated by said actuator ( 1 ); first means ( 17 ) for measuring the pressure difference (ΔP) existing between both chambers ( 9 , 10 ) of the hydraulic jack ( 8 ); second means ( 19 ) for calculating a correcting parameter (Pc), using said pressure difference (ΔP), said second means ( 19 ) including elements for calculating said correcting parameter (Pc) using the following expressions: { Pc = 1 - λ λ = (  Δ ⁢ ⁢ P  - Δ ⁢ ⁢ P ⁢ ⁢ 1 ) / ( Δ ⁢ ⁢ P ⁢ ⁢ 2 - Δ ⁢ ⁢ P ⁢ ⁢ 1 ) λ ∈ [ 0 , 1 ] wherein: ΔP represents said measured pressure difference; and ΔP 1 and ΔP 2 are two predetermined values which depend on said limit pressure; third means ( 20 ) for calculating, from said correcting parameter (Pc) and said set point, an auxiliary set point which enables, when it is applied to the electric motor ( 4 ), to limit the pressure difference between both chambers ( 9 , 10 ) of the hydraulic jack ( 8 ) to a limit pressure which is lower than an opening pressure of the pressure relief valve ( 11 ); and fourth means ( 23 ) for applying to said electric motor ( 4 ) said auxiliary set point, instead of said set point.