WO2016198411A1

WO2016198411A1 - Long-reach arm element and robotic arm comprising such an element

Info

Publication number: WO2016198411A1
Application number: PCT/EP2016/062916
Authority: WO
Inventors: Nolwenn KAMMERER; Yann Perrot; Dominique Ponsort
Original assignee: Commissariat A L`Energie Atomique Et Aux Energies Alternatives
Priority date: 2015-06-11
Filing date: 2016-06-07
Publication date: 2016-12-15
Also published as: FR3037270B1; FR3037270A1; EP3307492A1

Abstract

Arm element (10) comprising: - a first and a second, substantially parallel upright (20, 30); - a driving rod (40) having ends (43) hinged to the first and the second upright (20, 30); - a first and a second connection element (50, 60) which extend substantially parallel to the driving rod (40) and which are coupled to the first upright (20) and the second upright (30); - a controllable-length linear actuator (70) coupled between one of the uprights (20, 30) and the other upright (20, 30) or the driving rod (40); the first and second connecting elements (50, 60) being provided with counterbalancing means (55, 57, 65, 67) such that, when one of the connecting elements (50, 60) is kept under tension under the effect of the actuator (70), the other of the connecting elements (50, 60) is counterbalanced.

Description

High-slenderness arm element and robotic arm including such an element

FIELD OF THE INVENTION

The present invention relates to the field of robotic arms and more particularly the robotic arms with high slenderness. An element is said to be very slender when it has a significant length for a low weight.

BACKGROUND OF THE INVENTION

Articulated arms are known comprising several longitudinal elements articulated between them and whose joints comprise actuators. These arms are extensively used for handling tasks, for automated tasks or for remote operation. The disadvantage of such arms remains their reach. Indeed, increasing the length of the longitudinal elements causes an increase in their weight, their inertia and then forces to size accordingly the actuators and the fixed point of the articulated arm: ground base or wall recess. It has been envisaged to use longitudinal elements whose sections decrease as they move away from the fixed point of the arm, as is common practice in the field of telescopic cranes. This solution, however, does not allow a standardized manufacture of the longitudinal elements nor a modular design of the arm.

It is known to manipulate a load using a deformable parallelogram system. Such a system generally comprises a first fixed amount on which are articulated the first ends of two parallel rods. The second ends of the connecting rods are articulated on a second amount parallel to the first. A cylinder extends between the first end of a first rod and the second end of the other rod. Of the- folding or retraction of the cylinder makes it possible to modify the shape of the deformable parallelogram and thus to modify the position of a load linked to the second amount. In the case of a deformable parallelogram system in which the rods extend in a substantially horizontal direction, and at the end of which a heavy load (effort due to the weight directed substantially vertically downwards) is fixed, the lower rod is stressed in compression and the upper link is biased in traction. When the direction of the force is reversed, that is to say that it is directed substantially vertically upwards, the upper link is biased in compression and the lower link is biased in traction. Thus, it is necessary to size each connecting rod so that it can withstand forces in traction and compression. Such a design leads to massive rods which does not offer a solution to obtain large ranges for reduced weight.

OBJECT OF THE INVENTION

An object of the invention is to improve the hotpot of an arm member while limiting its weight.

SUMMARY OF THE INVENTION

For this purpose, there is provided, according to the invention, an arm element comprising:

a first amount and a second substantially parallel amount;

a steering rod having a first end and a second end respectively hinged to the first upright and the second upright by a first hinge and a second hinge;

a first connecting element and a second connecting element which extend substantially parallel to the steering rod and which each comprise a first end and a second end respectively; hitched on the first and second uprights on both sides of the connecting rods;

a linear actuator of controllable length coupled between one of the uprights and the other upright or the connecting rod.

The first connecting elements and the second connecting element are provided with means of neutralization so that, when one of the connecting elements is kept in tension under the effect of the actuator and forms with the steering rod and the two uprights. a deformable quadrilateral stiffened by the actuator, the other of the connecting elements is neutralized and does not transmit any effort between the first amount and the second amount.

Thus, the dimensioning of the connecting elements only takes into account tensile stresses resulting in lighter elements than for a design taking into account forces in tension and in compression. This particular dimensioning results in an optimization of the mass of the connecting elements which makes it possible to significantly increase the range of an arm element with respect to a prior art arm element of identical mass.

According to a particular embodiment, the guide rod is tubular and its wall extends around the connecting elements and one actuator. The wall of the steering rod then allows physical protection of the connecting elements and the actuator against shocks.

Advantageously, the neutralization means comprise at least one oblong slot. Such an embodiment is reliable and economical to achieve.

The invention also relates to a robotic arm comprising at least one robot arm element previously defined.

Other features and advantages of the invention will emerge in the light of the following description of a non-limiting embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to the appended figures among which:

- Figure 1 is a perspective representation of a robotic arm according to the invention;

FIG. 2 is a perspective view of an element of the arm of FIG. 1;

FIG. 3 is a detailed view of a robotic arm element of FIG. 2;

FIG. 4 is a partial perspective view of an exploded section of the arm element of FIG. 2;

FIG. 5 is a schematic view of the arm element of FIG.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIGS. 1 to 5, a robotic arm 100 comprises a first arm member 10, a second arm member 11 and a third arm member 12 articulated together along substantially vertical axes. Each arm member 10, 11, 12 comprises a linear actuator connected to a control unit 101. The third arm member 12 comprises at its end 12.1 a support 80 of a feeler 81.

The arm members 10, 11 and 12 being identical, only the first element 10 will be described below.

The first arm member 10 is attached to the wall mount 1 and includes:

a first upright 20 and a second upright 30 substantially parallel;

a cylindrical guide rod 40 of cylindrical wall 41 and having a first end 42 and a second end 43 respectively articulated on the first upright 20 and the second upright 30 by a first hinge 44 and a second hinge 45;

a first connecting element 50 and a second connecting element 60 which extend substantially parallel to the guide rod 40.

The first connecting element 50 is a square section rod 51 which is located above (according to the representation of FIG. 1) of a plane P comprising the axes of the articulations 44 and 45 of the steering rod 40. The first element link 50 comprises a first end 52 and a second end 53 respectively hitched to the first upright 20 and to the second upright 30. As particularly visible in FIG. 4, the first end 52 of the first connecting element 50 comprises a yoke 54 in which is pierced an oblong slot 55 whose largest dimension extends in the longitudinal direction of the first connecting element 50. This oblong slot 55 receives a hinge pin 21 rotatably mounted in a bearing 22 integral with the first upright 20. second end 53 of the first connecting element 50 is connected identically to the second upright 30 by means of a yoke 56 provided with a light oblong 57 and in which extends a hinge pin 31 rotatably mounted in a bearing 32 integral with the second upright 30.

The second connecting element 60 is identical to the first connecting element 50 and comprises a square section rod 61 which is located below (according to the representation of FIG. 1) of the plane P. The second connecting element 60 comprises a first end 62 and a second end 63 respectively hitched to the first upright 20 and the second upright 30. The first end 62 of the second connecting element 60 comprises a yoke 64 in which is pierced a light oblong 65 whose largest dimension extends in the longitudinal direction of the second connecting member 60. This oblong slot 65 receives a hinge pin 23 rotatably mounted in a bearing 24 secured to the first upright 20. The second end 63 of the second connecting element 60 is connected in identical manner to the second upright 30 by means of a yoke 66 provided with an oblong slot 67 and in which extends a hinge pin 33 rotatably mounted in a bearing 34 secured to the second amount 30.

An electric jack 70 is coupled at a first end 71 on the axis 21 and at a second end 72 on the articulation 45.

As can be seen in FIGS. 1 and 2, the wall 41 of the tubular connecting rod 40 extends around the first and second connecting elements 50 and 60 and the electric jack 70. The wall 41 also comprises two longitudinal windows 46 and 47.

The first upright 20 comprises, on its end opposite to that receiving the axes 21 and 23, a yoke 25 whose sides 25.1 and 25.2 extend perpendicular to a plane comprising the axes 21 and 23. The yoke 25 is integral in rotation with a shaft 26 pivotally mounted in flanks 2 and 3 projecting from the wall support 1. The shaft 26 is integral in rotation with an electric geared motor 27 not shown. The flanks 25.1 and 25.2 and the shaft 26 provide an articulation of the arm member 10 connected to the wall support 1. The rotational control of the electric geared motor 27 makes it possible to control the rotation of the arm member 10 with respect to the wall support 1.

The second upright 30 comprises on its end opposite to that receiving the pins 31 and 33, a yoke 35 whose flanks 35.1 and 35.2 extend perpendicular to a plane comprising the axes 31 and 33. The yoke 35 is integral in rotation with a shaft 36 on which is rotatably mounted the first upright 20.11 of the second arm member 11.

The yoke 35 comprises a bore in which is mounted an electric jack 37 (not shown) whose rod 38 extends to an axis 39 projecting laterally from the first upright 20.11. Deployment or retraction of the rod 38 makes it possible to control the relative rotation of the second arm member 11 with respect to the first arm member 10.

With reference to FIG. 5, the arm element 10 thus comprises a first deformable quadrilateral 13 comprising the first and second uprights 20 and 30, the first connecting element 50 and the guide rod 40. The arm element 10 comprises also a second deformable quadrilateral 14 comprising the first and second uprights 20 and 30, the second connecting element 60 as well as the guide rod 40. The electric jack 70 makes it possible to control the simultaneous deformations of the deformable quadrilaterals 13 and 14 so as to displace the amount 30 -and therefore the first amount 20.11 of the second arm member 11- on a circular path 90 shown in dotted line in Figure 5 and centered on the hinge 44.

The operation of the robotic arm element 10 will be described in connection with FIG. 5. When a heavy load P, the vertical component of which is directed downwards, is applied to the second upright 30, the internal forces to the arm member 10 are as follows:

- The electric jack 70 exerts a tensile force between the axis 21 and the hinge 45 in order to stiffen the deformable quadrilateral 13. The force exerted allows the equilibrium or the displacement of the second upright 30 subjected to the heavy load P; the first connecting element 50 is held in tension;

- The steering rod 40 is subjected to a compressive force;

the second connecting element 60 does not transmit any force between the first upright 20 and the second upright 30 because the oblong slots 65 and 67 neutralize the second connecting element 60 by ensuring that the first connecting element 50 comes into traction before the least one of the axes 23 or 33 comes into abutment against one end of the oblong slots 65 or 67.

When a load F, whose vertical component is directed upwards, is applied to the upright 30, the forces internal to the arm element 10 are as follows:

- The electric jack 70 exerts a compressive force between the axis 21 and the articulation 45 in order to stiffen the deformable quadrilateral 14. The force exerted allows the equilibrium or the displacement of the second upright 30 subjected to the load F ;

the second connecting element 60 is kept in tension;

- The steering rod 40 is subjected to a compressive force;

the first connecting element 50 does not transmit any force between the first upright 20 and the second upright 30 because the oblong apertures 55 and 57 neutralize the first connecting element 50 by ensuring that the second connecting element 60 comes into traction before at least one of the axes 21 or 31 comes into abutment against one end of the oblong slots 55 or 57.

Thus, there is obtained a robotized arm member 10 capable of supporting loads whose vertical component can be oriented upwards or downwards and whose connecting elements 50 and 60 intended to work in tension are not subject to any compression force. This design allows the implementation of lightweight connecting elements -car not having to withstand stress in compression- thus contributing to obtaining a high-slenderness arm member 10.

The robotic arm 100 consisting of the first arm member 10, the second arm member 11 and the third arm member 12 thus allows a large working range for a reduced cantilevered mass. The actuators of each articulation as well as the electric cylinders 70, 70.11 and 70.12 respectively of the first, second and third arm members 10, 11 and 12 being connected to a control unit 101, the robotic arm 100 can be controlled to reach almost everything. point located in a half sphere whose radius is substantially equal to the maximum capacity of the robotic arm 100.

Of course, the invention is not limited to the embodiment described but encompasses any variant within the scope of the invention as defined by the claims.

In particular,

- Although here the robotic arm comprises three arm members, the invention also applies to a robotic arm comprising a different number of arm members such as for example a single element, two or more arm members;

- Although here the arm members are articulated to each other along substantially vertical axes, the invention also applies to different orientations of the axes of the joints such as horizontal axes, or oriented in any way the axes of each articulation that can be oriented differently from one another; although here the articulation of the third arm is connected to a probe, the invention also applies to other types of control device such as a camera, a camera, an ultrasonic or radiographic sensor. or a three-dimensional scanner;

- Although here the first arm member is attached to a wall bracket, the invention is also applicable to an arm member connected to other types of external device such as a support fixed to the ground or mobile;

- Although here the first and second amounts are substantially parallel, the invention also applies to different orientations of the first and second amount such as non-coplanar or secant orientations;

- Although here the first and second elements both have a square section, the invention also applies to first and second elements that can adopt different sections in surface and shaped such as tubular sections, circular, rectangular, triangular, ellipsoid or any;

- Although here the first connecting element is located above a plane P comprising the axes of the joints of the steering rod and the second connecting element is located below this same plane, the invention s' also applies to other arrangements in which the first connecting element and the second connecting element are located on either side of the joints of the steering rod;

- Although here the joints of the connecting elements on the uprights are made using pins mounted in bearings, the invention is also applicable to other types of joints such as for example joints implementing bearings, or mounting sets leaving free rotations about the axis of the joint;

although here the two ends of the connecting elements comprise an oblong slot, the invention also applies to other means of neutralization such as for example a single oblong slot positioned at one end of each connecting element, an oblong slot located between the two ends of the connecting elements by which two connecting half-members are connected, flexible connecting elements such as cables, chains or connecting elements provided with a deformable element in compression but not in traction;

- Although here an electric cylinder extends between an axis of articulation of the first connecting element connected to the first amount and an articulation of the connecting rod connected to the second amount, the invention also applies other types of linear actuators of controllable length, such as for example a hydraulic or pneumatic cylinder, which can also be coupled between one of the uprights and the steering rod either on one of its ends or on a point of the steering rod located between its two ends;

although here the articulation of the first arm element on the wall support is controlled in rotation by a geared motor, the invention also applies to other types of means for controlling the rotation of the arm element. as for example an electric cylinder, pneumatic or a hydraulic motor;

although here the first leg of the first arm member comprises a hinge connected to a wall bracket and the second leg of the first arm member comprises a hinge connected to another arm member, the invention also applies to joints intended to be connected to other types of external device such as tools or a handling hook;

- Although here the guide rod comprises a tubular wall extending around the connecting elements, the electric cylinder and also comprising two longitudinal windows, the invention also applies to a steering rod whose wall would be devoid of longitudinal windows or that would have one or more than two. The invention also applies to a solid rod (non-tubular) and / or any section.

Claims

An arm member (10) comprising:

- a first amount (20) and a second amount

(30) substantially parallel;

a steering rod (40) having a first end (42) and a second end (43) respectively hinged to the first upright (20) and the second upright (30) by a first hinge (44) and a second hinge (44); 45);

a first connecting element (50) and a second connecting element (60) which extend substantially parallel to the guide rod (40) and which each comprise a first end (52, 62) and a second end ( 53, 63) respectively hitched to the first upright (20) and the second upright (30) on either side of the joints (44, 45) of the steering rod (40);

- a linear actuator (70) of controllable length coupled between one of the uprights (20, 30) and the other upright (20, 30) or the steering rod (40);

the first connecting element (20) and the second connecting element (30) being provided with neutralization means (55, 57, 65, 67) so that when one of the connecting elements (50, 60) is maintained in tension under the effect of the actuator (70) and forms with the guide rod (40) and the two uprights (20, 30) a deformable quadrilateral (13, 14) stiffened by the actuator (70), the other of the connecting elements (50, 60) is neutralized and transmits no effort between the first upright (20) and the second upright (30).

The robotic arm element (10) according to claim 1, wherein the steering rod (40) is tubular and has a wall (41) extending around the connecting elements (50, 60) and the actuator (70).

Robotic arm element (10) according to claim 1, wherein the means for neutralizing each connecting element (50, 60) comprises at least one oblong slot (55, 57, 65, 67) slidably receiving an axis (21, 23, 31, 33), the length of the oblong hole being such that one of the connecting elements (50, 60) comes into traction before the axis (21, 23, 31, 33) of the neutralizing the other connecting element (50, 60) abuts against one end of the oblong slot (55, 57, 65, 67) in which it is received.

The robotic arm member (10) according to claim 3, wherein the oblong slot (55, 57, 65, 67) is located at one of the ends 52, 53, 62, 63) of the connecting members (50). , 60).

The robotic arm member (10) of claim 1, wherein the actuator (70) is an electric ram.

Robotic arm (100) comprising at least one robotic arm member (10, 11, 12) according to any one of the preceding claims.