Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H21/00—Gearings comprising primarily only links or levers, with or without slides
  • F16H21/02—Gearings comprising primarily only links or levers, with or without slides the movements of two or more independently-moving members being combined into a single movement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/44—Movable or adjustable work or tool supports using particular mechanisms
  • B23Q1/50—Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only, the rotating pairs being the first two elements of the mechanism
  • B23Q1/54—Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only, the rotating pairs being the first two elements of the mechanism two rotating pairs only
  • B23Q1/545—Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only, the rotating pairs being the first two elements of the mechanism two rotating pairs only comprising spherical surfaces
  • B23Q1/5462—Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only, the rotating pairs being the first two elements of the mechanism two rotating pairs only comprising spherical surfaces with one supplementary sliding pair
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H21/00—Gearings comprising primarily only links or levers, with or without slides
  • F16H21/46—Gearings comprising primarily only links or levers, with or without slides with movements in three dimensions

Definitions

• the present invention relates to the field of kinematic transformers. More particularly, it relates to a kinematic transformer transforming the movements of one or more moving parts into movements of a mobile tool, and vice versa.
• a kinematic transformer makes it possible to convert the movements according to several degrees of freedom of a mobile tool into “elementary” movements of a lower number of degrees of freedom of moving parts. In general, it is sought to obtain elementary movements with a single degree of freedom of the moving parts. Elementary movements can easily be produced by actuators, or easily be measured by sensors.
• Kinematic transformers are basically divided into two families: series transformers and parallel transformers. In the case of a series kinematic transformer, the mobile tool is connected to a single kinematic chain which includes the moving parts.
• An example of a series kinematic transformer corresponds to the robotic arms used in computer-assisted machining.
• a tool intended to machine a workpiece is carried at the end of a support arm which consists of several branches mounted in series and articulated with respect to each other.
• the pivoting of a branch relative to the neighboring branch is obtained by means of electric motors.
• By controlling the various electric motors with suitable signals it is possible to move the tool in space, possibly with six degrees of freedom.
• Such a kinematic transformer is often bulky and of complex structure.
• the electric motors being distributed at different locations on the support arm, the kinematic transformer has large moving masses which are detrimental to the performance of the transformer.
• a parallel kinematic transformer comprises several kinematic chains, each kinematic chain connecting the moving tool to a moving part or several moving parts.
• An example of a parallel kinematic transformer relates to a movement simulator for a motor vehicle chassis in which a motor vehicle chassis is mounted on a fixed base by four hydraulic cylinders, each cylinder having a first end connected to the base and a second end connected to the frame . The four cylinders are controlled independently to obtain the displacement of the chassis.
• Such a device is generally bulky, in particular in the case where it is desired to control a mobile tool having a high number of degrees of freedom.
• the present invention aims to obtain a parallel kinematic transformer occupying a small volume.
• the present invention aims to obtain a kinematic transformer for which the degree of freedom of each moving part is a degree of translation along a fixed axis.
• the present invention provides a device for reversible kinematic transformation of movements of at least three moving parts into movements of a mobile tool, each moving part being connected to the mobile tool. by an at least partly specific kinematic chain, in which the moving parts move in translation in parallel rectilinear directions, each kinematic chain comprising connecting elements equivalent in total to four pivoting links.
• the device is isostatic.
• the moving parts are aligned.
• the moving parts are regularly spaced.
• each kinematic chain comprises a ball joint and a pivoting link.
• each kinematic chain comprises two universal joints.
• FIG. 5 represents another exemplary embodiment of the kinematic diagram of FIG. 2.
• the principle of the present invention consists in transforming movements according to different degrees of freedom of the out ⁇ l mobile in as many parallel rectilinear movements of moving parts.
• the moving parts correspond to the moving parts of linear actuators.
• the present invention makes it possible to transform parallel rectilinear movements of mobile parts into movements according to different degrees of freedom of the mobile tool.
• FIG. 1 represents an example of a linear actuator 10 comprising a fixed base 11 and six moving parts or sections 12A to 12F. Each mobile section 12A to 12F is capable of moving autonomously, relative to the fixed base 11, along an axis parallel to an axis OZ, over a range, for example of 2 cm.
• the movable sections 12A to 12F are arranged so that their axes of movement are coplanar and regularly spaced, for example about ten centimeters.
• Each movable section 12A to 12F has a bore 13A to 13F which can receive means for fixing an external element on the movable section 12A to 12F.
• the different bores 13A to 13F are coaxial along an axis OX, perpendicular to the axis OZ.
• the plane (XOZ) forms a median plane of the mobile sections 12A to 12F.
• the OZ and OX axes form with an OY axis perpendicular to the plane (XOZ) an orthonormal reference.
• FIG. 1 Six mobile sections 12A to 12F have been shown in FIG. 1. It is clear that the linear actuator 10 can comprise a variable number of mobile sections according to the desired use as will appear hereinafter. In addition, a limited number of mobile sections 12A to 12F can be used from the six available mobile sections of the linear actuator 10 in FIG. 1. An example of a linear actuator of this type is described in European patent EP 0365441 of the plaintiff. A condition for obtaining a kinematic transformer which has a minimum of structural play and friction energy loss is that the kinematic transformer is isostatic. FIG.
• FIG. 2 shows a possibility of a kinematic diagram of a parallel isostatic kinematic transformer transforming the movements of a mobile object 20 having three degrees of freedom into translation movements of three mobile sections 12A, 12B, 12C and vice versa.
• the mobile tool 20 is connected to the three mobile sections 12A, 12B, 12C by corresponding kinematic chains 22A, 22B, 22C.
• Each kinematic chain 22A, 22B, 22C comprises several rigid branches 23, each branch 23 being connected to another branch by a pivoting connection 24, that is to say a connection with a degree of freedom of rotation.
• a pivoting connection can correspond to two coaxial shafts mounted to rotate freely with respect to each other, two successive pivoting connections can correspond to a cardan joint, and three successive pivoting connections to a ball joint.
• a condition for a kinematic diagram of this type to correspond to a feasible kinematic transformer is that each pair of kinematic chains 22A, 22B, 22C comprises in total at least seven pivoting connections 24.
• FIG. 2 represents a kinematic transformer, the three chains of which kinematics 22A, 22B, 22C each comprise four pivoting connections 24.
• FIG. 3 represents an exemplary embodiment of a kinematic transformer according to the kinematic diagram represented in FIG. 2. The invention uses the actuator 10 represented in FIG.
• the mobile tool 20 consists of a tripod, the three feet 26A, 26B, 26C of which are equidistant from each other.
• a rod 27 is fixedly attached at one end to the tripod 20.
• the opposite end of the rod 27 is fixedly attached to a handle spherical 28 intended to be manipulated by a user.
• the rod 27 and the spherical lever 28 can be replaced by any type of end piece, for example a spherical end piece, cruciform, etc., depending on the intended use of the kinematic transformer.
• Each leg 26A, 26B, 26C is connected to a movable edge 12A, 12B, 12C of the actuator 10 by a kinematic chain 22A, 22B, 22C.
• the suffixes A, B, C denote belonging to one of the kinematic chains 22A, 22B, 22C.
• Each kinematic chain 22A, 22B, 22C has a return system 30A, 30B, 30C, in the shape of an "L”, fixedly attached at one end to the movable edge 12A, 12B, 12C, at the bore 13A, 13B , 13C, and connected at the opposite end to a first universal joint 31A, 31B, 31C.
• the first gimbal 31A, 31B, 31C is connected to one end of an arm 32A, 32B, 32C which can, for example, have a length of 50 mm.
• the opposite end of the arm is connected to a second gimbal 33A, 33B, 33C also connected to a foot 26A, 26B, 26C of the tripod 20.
• the return systems 30A, 30B, 30C, and the arms 32A, 32B, 32C have identical shapes and dimensions for the three kinematic chains 22A, 22B, 22C.
• FIG. 4 represents an exemplary embodiment of the first and second cardan joints 31A to 31C and 33A to 33C. By way of explanation, FIG. 4 represents the first universal joint 31A.
• the gimbal 31A comprises a first shaft 35A, of axis 36A, one end of which is fixedly attached to the return system 30A, and a second shaft 37A, of axis 38A, of which one end is fixedly attached to the arm 32A.
• the opposite end of the first shaft 35A is extended by a first fork 39A in which is mounted free in rotation a first cylindrical branch 40A, of axis 41A, of a cross 42A.
• the opposite end of the second shaft 37A is extended by a second fork 43A in which a second cylindrical branch 44A, of axis 45A, of the spider 42A is mounted for free rotation.
• the axes 41A and 45A are intersect at point 46A called the center of the first gimbal 31A.
• the axes 41A and 45A, 36A and 41A, and 38A and 45A are perpendicular two by two.
• the second universal joints 33A to 33C have a structure similar to that of the first universal joints 31A to 31C.
• the first shafts 35A to 35C of the second cardan shafts 33A to 33C are integrally connected respectively to the arms 32A to 32C, and the second shafts 36A to 36C are respectively integrally connected to the feet 26A to 26C of the tripod 20.
• return systems 30A and 30C make it possible to place the centers 46A and 46C of the first universal joints 31A and 31C respectively at a distance of approximately 2 centimeters from the plane (XOZ) on the side of the negative Ys.
• the return system 30B makes it possible to place the center 46B of the first gimbal 46B respectively at a distance of 2 centimeters from the plane (XOZ) on the side of the positive Ys.
• the axes 36A, 36B, 36C of the first universal joints 31A, 31B and 31C are oriented along the axis OZ.
• the axes 41A, 41B, 41C of the first universal joints 31A, 31B, 31C are therefore parallel to the plane (XOY).
• the first universal joint 41A of the kinematic chain 22A is arranged so that the axis 41A makes an angle of +135 degrees in the trigonometric direction with the axis OX.
• the first gimbal 31C is arranged so that the axis 41C makes an angle of +45 degrees relative to the axis OX.
• the first gimbal 31B is arranged so that the axis 41B is oriented along the axis OY.
• the second universal joints 33A, 33B, 33C are oriented so that the three centers 46A, 46B, 46C of the second universal joints 33A, 33B, 33C are arranged in an equilateral triangle, inscribed for example on a circle 40 mm in diameter.
• the axes 45A, 45B, 45C of the second universal joints 33A, 33B, 33C are tangent to this circle. For the embodiment of FIG.
• FIG. 3 shows another embodiment of a kinematic transformer according to the kinematic diagram of Figure 2. Two transformers are shown side by side so as to cooperate with the six sections (not shown) of the actuator 10.
• each kinematic chain 22A, 22B, 22C of a transformer comprises a return system 30A, 30B, 30C fixed integrally at one end to a movable edge 12A, 12B, 12C (not shown) of the actuator 10 and connected at the opposite end to a ball 63A, 63B, 63C.
• An arm 64A, 64C is connected to the ball 63A, 63B, 63C of each kinematic chain 22A, 22B, 22C and is free according to the three degrees of freedom of rotation at the center of the ball 63A, 63B, 63C.
• Each arm 64A, 64B, 64C is extended by a fork 65A, 65B, 65C, the two branches of which are crossed by a shaft 66A, 66B, 66C with respect to which the foot 26A, 26B, 26C of a tripod pivots.
• the mobile tool 20 is constituted by the tripod, the three feet 26A, 26B, 26C of which are equidistant from each other.
• An orifice 67 is provided in the tripod, possibly for fixing a rod as in the embodiment shown in FIG. 1.
• the return systems 30A and 30C allow the centers of the ball joints 63A and 63C to be placed respectively at a distance about 2 centimeters from the plane (XOZ) on the negative Y side.
• the return system 30B makes it possible to place the center of the ball 63A at a distance of 2 centimeters from the plane (XOZ) on the side of the positive Ys.
• the centers of the three ball joints 63A, 63B, 63C are distributed so that in the rest position the arms 64A, 64C are substantially oriented in the direction Z and the tripod 20 extends substantially along a plane parallel to the plane (XOY).
• Two kinematic transformers can be placed on the same actuator 10, a kinematic transformer being the symmetrical of the other relative to the plane (XOZ).
• the structure of the transformer according to the embodiments described above makes it possible to obtain a regular movement of the mobile object 20.
• the present invention has numerous advantages. It transforms the movements of a tool
• the invention can be used to control the movements of the mobile tool by appropriately controlling the actuator.
• the invention can also be used to produce electrical signals by measuring the displacements of the moving parts caused by movements imposed on the mobile tool to drive an external element from these signals.
• a feedback force can also be transmitted to the mobile tool by the actuator as a function of the movements of the mobile tool.
• the present invention allows great modularity. Indeed, many parts can be common to the different embodiments. For example, the return systems of the embodiment of the figure are identical. In addition, the embodiment shown in FIG.
• the tool can easily be modified according to the use of the kinematic transformer.
• the tool can be in the form of a control lever and can be used to make an electric gearbox with return effort.
• the tool can have the shape of a cross. With the shape shown in Figure 3, the mobile tool can be used to simulate the movements of an archer.
• the embodiment of Figure 5 is particularly 'suitable for use in system with two degrees of freedom, for example wherein the tool is controlled to move in a plane.
• the tool has the shape of a rod, and the end of the rod is slaved to move in a plane.
• the present invention is susceptible to various variants and modifications which will appear to those skilled in the art.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)
• Manipulator (AREA)

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Family Cites Families (9)

• 2004
  • 2004-03-10 FR FR0450482A patent/FR2867539B1/fr not_active Expired - Fee Related
• 2005
  • 2005-03-10 EP EP05739428A patent/EP1730422A1/de not_active Withdrawn
  • 2005-03-10 CA CA002578620A patent/CA2578620A1/fr not_active Abandoned
  • 2005-03-10 WO PCT/FR2005/050155 patent/WO2005088167A1/fr active Application Filing

Non-Patent Citations (1)

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