Abstract: The method comprises using a transmitting unit and at least two receiving units (8,10) arranged in two different places along well equipment (2). Each receiving unit forms an image or signature of wall portions which pass it. The signatures of wall portions formed by the lower receiving unit (8) when the well equipment is being lowered into the well are stored and the upper receiving unit (10) stores signatures coming from the wall portions which were previously stored by the lower receiving unit. A comparison (for example a correlation) of the signatures respectively coming from the two receiving units allows a common wall portion which has produced two substantially identical compared signatures to be identified. The time interval between the formation of the two substantially identical signatures is measured and the rate of penetration is calculated. As application of the invention is for the measurement of the true rate of penetration of a well tool or of a measuring sonde.

Abstract: A flexible bellows connecting device which positions an output member has a pair of jacks (1,2) equipped with deformation sensors (12,13). A pair of variable capacity bellows pump reservoirs (3,4) permit predetermined motion of the jacks. An electric motor (19) drives the pump. The sensor signals provide deformation difference signal feedback to the electronic control system which may include a microprocessor (5) for closed loop position control.

Abstract: Movable link device with a plurality of freedom degrees between a carrier element (manipulator arm or the like) and a carried element (tool, and particularly gripping tool). The device comprises a support frame (1) adapted to be secured to the carrier element, a movable frame (2) to which the carried element is fixed, a plurality of jacks (5, 6, 7, 7', 8) arranged between the support frame (1) and the movable frame (2) so as to maintain the latter with respect to the former in a relative position as a function of the deformation states of said jacks, and remote control means (13) to control the jacks and comprising a variable capacity tank associated to each jack and forming therewith a closed fluid circuit. The invention is applicable to robotics in order to move a member with high power and precision.

Abstract: A device for permitting the relatively precise positioning of two geometrical axes respectively of two elements at least one of the elements being associated with means capable of assuring its displacement characterized in that it comprises in combination at least two acoustic emitters-receivers disposed in a first plane substantially perpendicular to one of said geometrical axes, said axis being defined as the first axis, and capable of emitting toward said axis, said two emitter-receivers not being located on a same line passing through said first axis and in that it comprises a third emitter-receiver situated outside of said plane.

Abstract: Method for placing two submerged elements in a relative determined position, particularly in view of their mutual connection, comprising a first step of controlling the relative displacement of said elements on the basis of the measurement of electric values so as to ensure the alignment of a central point of one end of one element with the longitudinal axis of the other and a second step of progressively bringing the two elements in contact with each other by their relative displacement controlled on the basis of the measurement of their relative distance and mutual inclination angle, by means of acoustic emitters-receivers.

Abstract: The invention relates to a tactile pick-up for making contact with an object and emitting signals which are representative of the deformation caused by the object. The pick-up comprises a supple layer of variable electrical conductivity as a function of its state of compression, a matrix of measuring electrodes each connected to an output lead, and a large number of conducting elements connected to an electric source fixing their potential at a determined excitation value.