DEVICE FOR HANDLING A LOAD WITH GRAVITY COUPLING

Description

Domaine technique

[0001] The invention relates to manipulation devices, also called manipulators, which facilitate the handling of heavy objects within a workspace. Art antérieur

[0002] In many fields of activity, particularly in the industrial sector, it is common to have to handle heavy loads, i.e. on the order of several kilograms to several tens or even hundreds of kilograms.

[0003] In such situations, it can be helpful to use a handling device to facilitate the movement and / or positioning of the load in the workspace. Using a handling device, for example, helps prevent certain health risks such as musculoskeletal disorders (MSDs) or back pain by limiting the need for manual handling of the load. Furthermore, while several people are often required to carry, move, and position a heavy load by hand, a single person is generally sufficient to operate a handling device to achieve the same result.

[0004] There figure 1 This diagram presents a schematic example of a prior art load handling device, such as those found in many industries. Such a handling device DM' generally comprises a motorized articulated handling arm BA', connected at one end to a base B' around which it can pivot. The base B' serves as a mounting bracket for the handling device. The articulated arm BA' is formed from a series of segments (three in this example). figure 1 (referenced S1, S2 and S3) connected to the base B' or to each other by joints (for example, pivot joints, such as the joints referenced A1, A2 and A3 in the example of the figure 1 The load to be handled, C', is fixed to the other, free end of the articulated arm, at an end effector comprising fastening means (not shown in the diagram). figure 1 ) dedicated to this purpose, for example means of gripping the load C'.

[0005] In such a prior art manipulation device, equilibrium is achieved through the various torques present at the joints. Thus, at rest, the torque C3 at joint A3 opposes the mass of the assembly formed by the effector (including any load C' attached to this effector) and segment S3, and the torque C2 at joint A2 opposes the mass of the assembly formed by the effector (including any load C' attached to this effector) and segments S2 and S3. The torque C1 at joint A1 only comes into play during movement, but the pivot joint A1 must nevertheless be dimensioned to maintain the wrench T1 related to the weight of the articulated arm BA' and prevent tipping.

[0006] Typically, in this type of industrial robot with a so-called "serial" structure, gravity compensators (not shown) are also positioned at the base B' of the manipulation device, in order to compensate at least partially for the mass of the articulated arm.

[0007] However, the existing load handling devices described above have some drawbacks.

[0008] Firstly, gravity compensation aids are often inconsistent across the workspace. More specifically, gravity compensators positioned at the base of the manipulation device generally only partially address the robot's mass and rarely that of the load.

[0009] Secondly, the fact that these handling devices are motorized (i.e., controlled via a joystick or remote control) deprives the user of any physical perception of the moving load's behavior. For example, the user is no longer able to grasp, even partially, certain characteristics of the moving load, such as its mass or inertia, even though this information is essential for precise guidance within the workspace.

[0010] Thirdly, existing handling devices are often complex and expensive, particularly due to the electronics they incorporate for motorization and the sophisticated gravity compensation mechanisms at their base. As a result, they are not always suitable for use by certain trades or in certain demanding environments, such as those in the construction sector, where the focus is on equipment that is simple (to use and move), reliable, easy to use both indoors and outdoors, including in humid (e.g., rain) or particularly dusty environments, and competitively priced.

[0011] Document FR2375011 presents a load handling device as defined in the preamble to claim 1 of this application.

[0012] Therefore, there is a need for a load manipulator with a simple and robust design that does not present the constraints of existing handling devices. Résumé de l'invention

[0013] The present technique offers a solution to overcome certain drawbacks of the prior art. This technique relates to a load-handling device comprising a first articulated arm extending from a base of the device to a free end of the first articulated arm, which includes means for securing the load. The first articulated arm is formed from a series of segments connected by joints. According to the general principle of the present technique, the device also comprises: a second articulated arm formed of a succession of the same number of segments as said first articulated arm, connected to each other by the same type of joints as those of said first articulated arm, said first and second articulated arms extending on either side of said base, each segment of said second articulated arm being shorter in length and of greater mass than a segment of the same position, said associated segment, of said first articulated arm, said length and mass being dimensioned so that the mass-length product is substantially equivalent for two associated segments; means for transmitting movements between associated segments, said transmission means being configured so that a movement of a segment of one of the two articulated arms causes a movement of the same amplitude of the associated segment of the other articulated arm.

[0014] In a particular embodiment, the segments of said first articulated arm and / or said second articulated arm have a deformable parallelogram structure.

[0015] In a particular embodiment, said transmission means belong to the group comprising transmission means by gears, by belts, and / or by chains.

[0016] According to the invention, said transmission means extend at least in part to said base.

[0017] According to the invention, said base includes means for motorizing said transmission means.

[0018] In a particular embodiment, said second articulated arm includes, at its free end, means for fixing a compensating load.

[0019] According to a particular feature of this embodiment, the said means for fixing a compensating load are positioned at the level of an effector of variable length.

[0020] In a particular embodiment, at least one of the segments of said second articulated arm includes a movable weight along said segment.

[0021] The different embodiments mentioned above can be combined with each other for the implementation of the invention. Figures

[0022] Other features and advantages of the invention will become clearer upon reading the following description of a preferred embodiment, given by way of simple illustrative and non-limiting example, and the accompanying drawings, among which: [ Fig 1 ] presents a simplified diagram of a prior art manipulation device; [ Fig 2 ] presents a simplified diagram of an example of a manipulation device, in a particular embodiment of the proposed technique; [ Fig 3a ] presents a simplified diagram of another example of a manipulation device, in a particular embodiment of the proposed technique; [ Fig 3b ] presents a simplified diagram of another example of a manipulation device, in a particular embodiment of the proposed technique; [ Fig 3c ] presents a simplified diagram of another example of a manipulation device, in a particular embodiment of the proposed technique; [ Fig 4a ] presents a simplified diagram of another example of a manipulation device, in a particular embodiment of the proposed technique; [ Fig 4b ] presents another simplified diagram of the manipulation device illustrated in figure 4a , in a particular embodiment of the proposed technique. Description détaillée de l'invention

[0023] The proposed technique addresses some of the aforementioned drawbacks.

[0024] The proposed technique relates more specifically to a simple and robust structural load handling device, which can be implemented purely mechanically in at least one embodiment, and is suitable for use in complex environments (for example, outdoors, in difficult humidity or temperature conditions, or in particularly dusty environments). By way of illustration and without limitation, the proposed handling device is, for example, particularly suitable for use in the construction sector, for activities such as handling and installing plasterboard, interior or exterior joinery, etc.

[0025] In all figures in this document, elements of a similar nature are designated by the same numerical reference.

[0026] A load-handling device according to the present technique is illustrated in relation to the figure 2 , in a particular embodiment. Such a manipulation device DM comprises two articulated arms BA1 and BA2 extending on either side of a base B, i.e., in diametrically opposite directions with respect to the base B. Depending on the application, the base B may take the form of a support for attaching the manipulation device to the frame, or a mobile platform (for example, mounted on casters) to facilitate the movement of the manipulation device. The first articulated arm BA1 includes, at its free end, an effector comprising attachment means (not shown in the figure). figure 2 ) of a CU load to be handled. Each of the two articulated arms BA1 and BA2 is formed of a succession of segments connected by joints (in a configuration of articulated arms of the "serial" type).

[0027] According to the general principle of the proposed technique, the two articulated arms BA1 and BA2 are otherwise of similar structure, in that they comprise the same number of segments, and in that segments in the same position in each of the two arms are connected to the preceding segment or to the base B by the same type of joint. In this document, the position of a segment within an articulated arm means the rank of that segment within the articulated arm in question, counting from the base of the manipulation device. It should be noted, however, that, within the framework of this technique, the various segments of the articulated arms BA1 and BA2, and in particular the segments in the same position in each of the two arms, are not necessarily made of the same material.

[0028] Thus, in the example of the DM manipulation device illustrated in figure 2 The articulated arms BA1 and BA2 each comprise three segments (segments S11, S12, and S13 for articulated arm BA1; segments S21, S22, and S23 for articulated arm BA2) and three joints (joints A11, A12, and A13 for articulated arm BA1; joints A21, A22, and A23 for articulated arm BA2). Joint A13, connecting the segments in the second (S12) and third (S13) positions of the first articulated arm BA1, is of the same type as joint A23, connecting the segments in the second (S22) and third (S23) positions of the second articulated arm BA2. This example is, of course, not limiting, and the articulated arms of a manipulation device according to the proposed technique may comprise two or more than three segments. As illustrated in the figure 2 , the two articulated arms are also generally configured to be able to pivot simultaneously around the base B - and more particularly around a support axis of these two arms (represented in dotted lines on the figures) - the rotation of one of the arms on one side of the base causing a similar rotation of the other arm on the other side of the base so that the two arms extend in substantially diametrically opposite directions with respect to the base B when the manipulation device is used.

[0029] According to the general principle of the proposed technique, each segment of the second articulated arm BA2 is shorter and has a greater mass, in the same proportions, than the segment in the same position of the first articulated arm BA1. In other words, the length and mass of any segment of the second articulated arm BA2 are dimensioned so that the mass-length product of this segment is substantially equivalent to the mass-length product of the corresponding segment (i.e., in the same position) of the first articulated arm BA1. This defines an association relationship between segments in the same position in each of the two articulated arms, the length-mass product of two associated segments being substantially equivalent.

[0030] According to the general principle of the proposed technique, the manipulation device also includes means for transmitting movements (not shown on the figure 2 between associated segments, these transmission means are configured so that a movement of a segment of one of the two articulated arms causes a movement of the same amplitude of the associated segment of the other articulated arm. These transmission means include, for example, transmission means using gears, belts, chains, cables, according to the principle of tensegrity, or a combination of these different means.

[0031] In other words, to put it simply, the second articulated arm is similar to a smaller, but heavier, version of the first articulated arm, and the positions of these two arms are synchronized to achieve, according to a principle of mass balancing, complete compensation of the mass of the first articulated arm regardless of its position in the workspace. To ensure this compensation, the two articulated arms are positioned on either side of an axis or a support point of the manipulation device, and mechanical transmission means are provided so that any movement of a segment of one of the two articulated arms results in a corresponding compensating movement of the segment in the same position in the other articulated arm, of the same amplitude. At any given moment, the configuration of the second articulated arm (defined by the respective positions, i.e.The angular relationships of the segments that compose it thus correspond, to a certain extent, to the result of applying to the first articulated arm the composition of a symmetry (which can be axial or central) and a homothety. As such, the... figures 3a , 3b And 3c present other examples of possible configurations for implementing a manipulation device according to the proposed technique, in addition to the one illustrated in relation to the figure 2 , all of which allow for complete compensation of the gravity of the first articulated arm (which can be called the "manipulator" arm) by a second articulated arm (which can be called the "compensating" arm), i.e., obtaining, at equilibrium, for the manipulation device, a center of gravity that remains positioned on the support axis of this device. Among these different configurations, we can distinguish in particular examples of "axial symmetry" type configurations (as in the case of figures 2 And 3a , in which the means of transmitting motion between associated segments are configured so that a rotational movement of a segment of one of the two articulated arms results in a rotational movement of the same amplitude but in the opposite direction of rotation of the associated segment of the other articulated arm) and examples of "central symmetry" type configurations (case of the figures 3b et 3c in which the means for transmitting motion between associated segments are configured so that a rotational movement of a segment of one of the two articulated arms results in a rotational movement of the same amplitude and direction of rotation of the associated segment of the other articulated arm).

[0032] In a particular embodiment of the proposed technique, the second articulated arm BA2 also includes, at its free end, at an end effector, means for attaching a load. Thus, the payload CU (i.e., the load to be handled) carried by the first articulated arm BA1 can also be at least partially compensated by a compensating load CC attached to the end of the second articulated arm BA2. In this way, it is possible, for example, to obtain complete compensation of the assembly formed by the first articulated arm BA1 and the payload CU when this payload CU is fixedly attached to the free end (i.e., at the end effector) of the first articulated arm BA1. If the payload CU is mobile relative to this end effector, partial but nonetheless significant compensation of this assembly can also be obtained when the payload is set in motion.In particular, the CC compensation load can be chosen by the user from various loads of varying masses, depending on the mass of the CU payload to be moved, as shown below, in relation to the . figure 4a .

[0033] There figure 4a presents another simplified diagram of a manipulation device in a configuration close to that illustrated in relation to the figure 2 In this particular embodiment of the proposed technique, the various segments of the first articulated arm BA1 and the second articulated arm BA2 have a deformable parallelogram structure (a four-bar mechanism linked by pivot joints), allowing the effectors located at the respective free ends of the two articulated arms to maintain a constant orientation (for example, a horizontal orientation), regardless of the position of these arms. This example is given purely for illustrative purposes and is not intended to be limiting; it is understood that other mechanisms for maintaining the orientation of the effectors, not based on a deformable parallelogram structure of the segments, can also be implemented in other embodiments of this technique (for example, solutions based on the use of measurements provided by one or more inclinometers positioned on the articulated arms).

[0034] On the figure 4a Examples of the relationships between the lengths and masses of the associated segments of the first and second articulated arms are also provided, thus further illustrating the general principle of the proposed technique. For example, in this example (with n a real number greater than 1): the first segment of the first articulated arm BA1, of length l 1 and mass m 1 , is associated with the first segment of the second articulated arm BA2, of length l 1 / n and mass n.m 1 ; the second segment of the first articulated arm BA1, of length l 2 and mass m 2 , is associated with the second segment of the second articulated arm BA2, of length l 2 / n and mass n.m 2 ; the third segment of the first articulated arm BA1, of length l 3 and mass m 3 , is associated with the third segment of the second articulated arm BA2, of length l 3 / n and mass n.m 3 ; the effector of the first articulated arm BA1 (which can be considered a fourth segment of the first articulated arm BA1), of length l 4 and mass m 4 , is associated with the effector of the second articulated arm BA2 (which can be considered a fourth segment of the second articulated arm BA2), of length l 4 / n and mass n.m 4 .

[0035] The first and second articulated arms BA1 and BA2 are therefore equivalent from the point of view of the mass-length product, the second articulated arm BA2 corresponding to a reduced version of a ratio n of the first BA1 articulated arm, but n times heavier.

[0036] As illustrated elsewhere in relation to the figure 4b ,And in accordance with the general principle described above, means for transmitting motion between associated segments are also implemented so that any movement of a segment of one of the two articulated arms results in a corresponding movement of the same amplitude of the associated segment of the other articulated arm. These means for transmitting motion, not shown in the figure 4a are partially illustrated on the figure 4b , in a particular embodiment (in a front view of the manipulation device in the upper part of the figure 4b , and in a top view of the lower part of the figure 4b More specifically, in this example, the transmission of motion is ensured by a belt mechanism (with, on the figure 4b (a green color code to represent the means of transmitting motion between the associated second-position segments in arms BA1 and BA2, and a yellow color code to represent the means of transmitting motion between the associated third-position segments in arms BA1 and BA2).

[0037] The mutual compensation of the two articulated arms is thus total in the workspace.

[0038] In the situation, as illustrated in relation to the figure 4a where an operator wishes to use the manipulation device DM to lift and then manipulate a payload of mass M, once the first articulated arm BA1 is in the position to pick up the payload and the latter is fixed to the effector at the free end of this manipulator arm BA1, they simply need to fix a compensating load of mass M to the effector located at the free end of the second compensating articulated arm BA2 n .M (withn(the real number greater than 1 as defined previously). In this way, a balance is created, with complete compensation not only for the handling device but also for the load throughout the entire workspace. The operator can then easily manipulate the grasped payload (i.e., move it within the workspace) without being completely deprived of the perception of certain physical quantities that characterize it, such as its mass or inertia, unlike handling devices according to the prior art. In other words, the design of the handling device according to the present technique is based on an approach that can be described as "human-centered," insofar as this device offers the user the ability to easily "feel" the behavior of the moved load and thus facilitate its precise positioning within the workspace.According to a particular feature, the operator has the ability to directly manipulate the second articulated arm (i.e. the compensating arm, smaller in size) to control the first articulated arm (i.e. the manipulator arm, smaller in size) and therefore, . in fine, the movement of the payload within the workspace.

[0039] In a particular embodiment, at least one segment of the second articulated arm includes a movable weight along the axis of that segment, which can, for example, be moved manually or automatically by means of a linear actuator (e.g., rack and pinion, worm gear, linear motor) fitted to the segment (the mass of such a weight being considered, within the scope of this document, as forming part of the overall mass of the segment in question). The movement of such a weight along a segment of the second articulated arm can thus be used to disrupt the equilibrium of the handling device (via the resulting displacement of the segment's center of gravity) and thereby generate a displacement of the payload carried by the first articulated arm.Following the same principle, the second articulated arm can also be equipped with means that, at the end effector located at its free end, allow the compensating load to be moved closer to or further from the base of the manipulation device (these means could, for example, take the form of linear actuators of the same type as those previously described, and allow, for example, the length of the end effector to be varied). Thus, assuming, for example, that these means are used, from an equilibrium position, to move the compensating load carried by the second articulated arm away from the base, the torques generated on the side of this second articulated arm will increase, causing an imbalance that will result in an upward displacement of the payload carried by the first articulated arm.Since the torques on the other segments of the second articulated arm are also modified following the displacement of the compensating load, the upward movement of the payload is accompanied by a horizontal displacement that can be considered a parasitic movement if the desired objective is a purely vertical displacement of the payload. However, knowing all the masses involved allows for the implementation of compensating mechanisms to eliminate this parasitic horizontal deviation. Similarly, the manipulation device using the proposed technique allows, according to the same principle, the creation of an imbalance that induces a horizontal displacement of the payload.

[0040] The general principle described in this document can, however, also be implemented, according to the invention, within the framework of active solutions including motorized elements to facilitate the use of the handling device. In this context, a handling device according to the proposed technique, i.e., with two articulated arms, remains advantageous compared to existing handling devices such as the one described in relation to the figure 1, in that it minimizes the amount of energy required to achieve the same effects (i.e., the same movements, with an equivalent payload) as a prior art device. In such embodiments, the motion transmission means between associated segments of the two articulated arms are, for example, configured to pass through or extend at least partially to the base of the handling device, and motorization means (or at least motorized assistance) for these motion transmission means may also be provided at this base, enabling assistance in moving the load to be handled.According to a particular characteristic, these means of propulsion include in particular possibly reversible motors, which can be used to accelerate or brake the movement of the payload, and be associated with means of energy recovery in order to further reduce the overall consumption of the system.

Claims

1. A handling device (DM) for handling a load, including a first articulated arm (BA1) extending from a base (B) of said device to a free end of said first articulated arm that includes attachment means for attaching said load, wherein said first articulated arm is formed by a succession of segments (S11, S12, S13) connected by articulated joints (A11, A12, A13), wherein said device includes - a second articulated arm (BA2) formed by a succession of a same number of segments (S21, S22, S23) as said first articulated arm, which are connected to each other by a same type of articulated joints (A21, A22, A23) as those of said first articulated arm, wherein said first and second articulated arms extend on either side of said base, wherein each segment of said second articulated arm is shorter in length and greater in mass than a segment in the same position, called the associated segment, of said first articulated arm, wherein the dimensions of said length and mass are calculated so that the mass-length product is substantially equivalent for two associated segments; - transmission means for transmitting movements between associated segments, wherein said transmission means are configured so that a movement of a segment of one of the two articulated arms causes a movement of the same magnitude of the associated segment of the other articulated arm, wherein said transmission means extend at least partly at said base, wherein said device is characterised in that said base includes motorisation means for motorising said transmission means.

2. A device according to claim 1, characterised in that the segments of said first articulated arm and / or of said second articulated arm have a structure with the form of a deformable parallelogram.

3. A device according to claim 1, characterised in that said transmission means belong to the group including transmission means via gears, belts and / or chains.

4. A device according to claim 1, characterised in that said second articulated arm includes, at its free end, attachment means for attaching a counterload.

5. A device according to claim 4, characterised in that said attachment means for attaching a counterload are positioned at an effector of a variable length.

6. A device according to claim 1, characterised in that at least one of the segments of said second articulated arm includes a weight that is movable along said segment.