ARTICULATED GRIPPER'S WRIST
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
- Filing Date
- 2022-12-16
- Publication Date
- 2026-07-31
Abstract
Description
Description Title of the invention: ARTICULATED GRIPPER WRIST Technical field
[0001] = The invention relates to the field of load manipulators, and more particularly- lately the field of gripping assemblies mounted at the end of such man- pulators. STATE OF THE PRIOR ART
[0002] = Conventionally, a load manipulator is provided at its end with a gripping assembly which includes a frame and an articulated controlled gripper relative to the chassis around one or more axes of rotation. Generally the articulation of the gripper comprises a first segment articulated around a first axis of rotation using a first geared motor. A second segment is articulated around a second axis of rotation - generally orthogonal to the first - in the end of the first segment using a second geared motor. This design allows for a clear decoupling of the two rotations but has several in- conveniences such as the power supply of the second gear motor which must accommodate the rotation of the first joint and the fact that the first geared motor must manage the inertia of the second geared motor. We obtain then a bulky, heavy and expensive gripping set. Such a set of gripping is not suitable to replace a human hand in interventions usually carried out using "glove boxes" which allow a user to intervene in a controlled environment from the outside environment by passing one's hands to the through openings provided with waterproof protective gloves. In fact, the wrist human groups together, in a reduced volume, several joints of the hand and the Current remote handling solutions do not offer architectures actuation system allowing a gripping assembly to be substituted for the human hand in “glove box” type applications.
[0003] = The object of the invention is to improve the compactness and the capacity to replace a human hand from a grasping assembly. Statement of the invention
[0004] — For this purpose, an articulated gripping assembly is provided comprising a chassis, a controlled gripper, a first articulation of the gripper around a first axis. The first joint is actuated by a first actuator comprising a first actuating wheel connected to a guide bearing of the rotating gripper around a second axis. The first wheel is driven using a first element for transmitting a tractive force which collaborates with a first wheel idler. The gripping assembly according to the invention also comprises a second articulation of the gripper around the second axis, the second articulation being actuated by a second actuator comprising a second actuating wheel connected to the gripper. The second wheel is driven using a second element for transmitting a tractive force which collaborates with a second idler wheel mounted to rotate relative to the chassis around a third axis. According to the invention, the second articulation comprises a first return of the second element for transmitting a tractive force to return the latter around the first axis. This produces a compact gripping assembly which is actuated using traction force transmission elements which allow the actuator motors to be placed on the same fixed structure and thus avoid having to manage mobile power supplies. Such a gripping assembly allows the two joints to be grouped together in a compact volume, resulting in a gripping assembly capable of replacing a human hand in a "glove box" type application. According to other particular, non-exclusive and optional embodiments of the invention: the second axis and / or the third axis is orthogonal to the first axis; the second element transmitting a traction force makes one turn death around the return of the second transmission element of an effort of traction; a second idler wheel support is also mounted to rotate around of a fourth axis substantially orthogonal to the third axis; the assembly comprises a first device for preloading the first element transmission of a traction force and / or a second device of preload of the second element transmitting a tensile force; the assembly includes a compensator intended to vary a first distance separating the third axis from the first axis as a function of a position angular rotation of the first drive wheel around the first axis; the compensator comprises a shaft which rotatably connects the first idler wheel and a compensation wheel, the compensation wheel cooperating with a third element for transmitting a tractive force which is connected to the second idler wheel; the shaft is mounted to rotate around a fourth axis substantially or- thogonal to the third axis; the second preloading device of the second transmission element of a tensile force includes a preloading device of the third element for transmitting a traction force; the second preloading device of the second transmission element of a tensile force includes a preloading device of a fourth element for transmitting a traction force from the second actuator; the assembly includes a selective compensator inhibition device; the assembly includes a braking device for selectively braking the second drive wheel; the braking device is arranged to apply a braking force to the second actuating wheel when a tension of the second cable is in- below a predetermined threshold; the second actuator is a rotary actuator. The invention also relates to an articulated arm comprising a gripping assembly as described above. The invention also relates to a method of using a gripping assembly as defined above, the method comprising the following steps: Step 1: Command a rotation of the second drive wheel around of the second axis in a first direction of rotation from a first angular position to a second angular position; Step 2: Activate the inhibition device; Step 3: Command a rotation of the first drive wheel way of reducing a voltage of the second transmission element of a tensile force from a working tension value to a value of clutch tension; Step 4: Command a rotation of the second drive wheel around of the second axis in a second direction of rotation opposite to the first direction of rotation; Step 5: Command a rotation of the first drive wheel way of restoring a tension of the second transmission element of a tensile force which is equal to the value of the working tension; Step 6: Deactivate the inhibition device Step 7: Order a new rotation of the second wheel actuation. When the gripping assembly comprises a braking device for selectively braking the second actuating wheel, the method comprises the following additional steps: a braking device activation step located between step 1 and step 3: a step of deactivation of the braking device located between step 5 and step 7. Other characteristics and advantages of the invention will appear on reading the following description of particular non-limiting embodiments of the invention. Brief description of the drawings [Fig.1] [Fig.1] is a schematic perspective representation of a gripping assembly according to a first embodiment of the invention; [Fig.2] [Fig.2] is a schematic perspective representation of a gripping assembly according to a second embodiment of the invention [Fig.3] [Fig.3] is a schematic perspective representation of a gripping assembly according to a third embodiment of the invention; [Fig.4] [Fig.4] is a schematic perspective representation of a gripping assembly according to a fourth embodiment of the invention; [Fig.5] [Fig.5] is a schematic perspective representation of a gripping assembly according to a fifth embodiment of the invention; [Fig.6] [Fig.6] is a schematic perspective representation of a gripping assembly according to a sixth embodiment of the invention; [Fig.7] [Fig.7] is a partial schematic perspective representation of a gripping assembly according to a seventh embodiment of the invention; [Fig.8] [Fig.8] is a detailed schematic representation of the gripping assembly of [Fig.7] in a first state; [Fig.9] [Fig.9] is a detailed schematic representation of the gripping assembly of [Fig.7] in a second state. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS With reference to [Fig. 1], the articulated gripping assembly according to the invention, and generally designated 1, is mounted on a distal segment of an articulated arm (not shown). The assembly 1 comprises a frame 10 on which is mounted a controlled gripper 20—here a gripper 20 with two jaws 21 and 22—and a first articulation 30 of the gripper 20 about a first pitch axis O1. The articulation 30 is actuated by a first cable jack 31 comprising a first screw 32 driven by a first nut (not shown) motorized by a first motor connected to a control unit (not shown). Such a cable jack with a driven screw is known to those skilled in the art. The cable jack 31 comprises a first actuating pulley 33 connected by an arm 33.1 to a first bearing 23 for guiding the gripper 20 in rotation around a second axis O2.The pulley 33 is driven using a first cable 34 secured to the screw 32 and which collaborates with a first driven pulley 35 mounted to rotate around an axis O35 substantially parallel to O1. The pulley 35 has a winding radius R35 identical to the winding radius R33 of the pulley 33. The cable 34 comprises a first strand 34.1 which passes through the screw 32 and the ends of which . are crimped onto the pulleys 33 and 35. The cable 34 also comprises a second strand 34.2, the ends of which are also crimped onto the pulleys 33 and 35. The assembly | also comprises a second articulation 40 of the gripper 20 around the second axis O2. The articulation 40 is actuated by a second cable jack 41 comprising a second driven screw 42 driven by a second nut (not shown) motorized by a second motor connected to the control unit. Such a cable jack with a driven screw is known to those skilled in the art. The cable jack 41 comprises a second actuating pulley 43 integral in rotation with the gripper 20 around the axis O2. The pulley 43 is driven using a second cable 44 integral with the screw 42 and which collaborates with a second driven pulley 45. The pulley 45 is mounted to rotate relative to the chassis 10, around a third axis O3, orthogonal to the axis O1 using a second bearing 45.1. The two ends of the cable 44 are crimped onto the pulley 43. As seen in [Fig.1], the articulation 40 comprises a first sheave 46.1 and a second sheave 46.2 mounted to rotate about the axis O1 to return the cable 44 about the axis O1. The sheaves 46.1 and 46.2 are located on either side of the pulley 43 so that the portion of the cable 44 which extends between the sheave 46.1 and the pulley 43 is tangent to the sheave 46.1 and to the pulley 43 and the portion of the cable 44 which extends between the sheave 46.2 and the pulley 43 is tangent to the sheave 46.2 and to the pulley 43. The sheaves 46.1 and 46.2 have the same winding radius R46. The compensator 50 comprises a shaft 51 which rotatably connects the pulley 35 and a compensation wheel 52 around the axis O35. The wheel 52 cooperates with a third cable 53 which is connected to a slidingly guided yoke 54 and on which the bearing 45.1 is mounted. The wheel 52 has a radius R52 substantially equal to the radius R46. The shaft 51 is guided in its rotation around the axis O33 by a third bearing 55. A rod 56 secured to the bearing 55 is mounted to rotate relative to the chassis 10 around a fourth axis O4 substantially orthogonal to the axis O3 using a fourth bearing 57. In operation, the movement of the gripper 20 around the axis O1 is controlled by driving a movement of the screw 32 using the first motorized nut. The movement of the screw 32 (here in a direction S1 shown in [Fig. 1]) causes a movement of the cable 34 over a first distance d34 and causes a rotation of the pulleys 33 and 35 respectively around the axes O1 and O35. The rotation of the pulley 35 around the axis O35 is transmitted to the wheel 52 by the shaft 51. This rotation of the wheel 52 causes an unwinding of the cable 53 which causes a movement of the bearing 45.1 over a second distance d45.1 which, here, is substantially equal to d34*(R52 / R35). Thus, the compensator 50 makes it possible to vary a distance D1 which separates the axis O3 from the axis O1 as a function of an angular position of the pulley 33 around the axis O1 and to avoid any parasitic rotation of the gripper 20 around the axis O2 during the rotation of the joint 30. When it is desired to move the gripper 20 around the axis O2, a movement of the screw 42 is commanded which, by moving the cable 44, causes a rotation of the pulley 43 around the axis O2. Elements identical or analogous to those previously described will bear a numerical reference identical to this one in the following description of the second, third, fourth, fifth, sixth and seventh embodiments of the invention. According to a second embodiment shown in [Fig.2], the assembly 1 comprises a first turnbuckle 36 for preloading the cable 34 located on the cable 34 and a second turnbuckle 58 for preloading the cable 44 located on the cable 53. Alternatively, the turnbuckle 58 can be installed on the cable 44, According to a third embodiment of the invention shown in [Fig.3], the second articulation is actuated by a third cable jack 60 - here of the driven nut and cable capstan type - and the cable 53 is without a turnbuckle 58. The cable jack 60 comprises a screw 61 mounted for rotation relative to the frame 10. The screw 61 is driven in rotation by an electric motor not shown. A nut 62 cooperates with the screw 61 and comprises a ring 63 projecting radially from the nut 62. Ropes 64.1 and 64.2 connect the ring 63 by crimping to a first intermediate support 65 and a second intermediate support 66, both in the form of a ring. The support 65 is also connected by crimping to a portion of the cable 44 which extends from the pulley 45 to the support 65. The support 66 is connected by crimping to a portion of the cable 44 which extends from the sheave 46.1 to the support 66. The cable jack 60 also comprises a fourth pulley 67 mounted for rotation about the axis O1 and integral in rotation with the sheave 46.1 as well as a fifth pulley 68 mounted for rotation about an axis O68 substantially parallel to the axis O1 using a bearing 69. The bearing 69 is connected to the frame 10 by a rod 70 guided in translation and to which a third turnbuckle 71 is connected. A fourth cable 72 extends from the support 65 to the pulley 68 on which it is wound to then extend towards the pulley 67 and wind above to join support 66. The actuation of the second articulation 40 is [acted by controlling a rotation of the screw 61. The preloading of the cable 44 is done by acting on the turnbuckle 71. By applying a tension on the rod 70, this tension is transmitted to the cable 72 by the pulley 68. The tension of the cable 72 is transmitted to the cable 44 by means of the supports 65 and 66 which, by being articulated by the ropes 64.1 and 64.2 on the nut 62, achieve a tension balancing without exerting any parasitic torque on the nut 62. This produces a device which preloads the cable 44 by applying a preload to the cable 72 of the cable jack 60. According to a fourth embodiment shown in [Fig.4], the sheaves 46.1 and 46.2 are provided with helical grooves and the cable 44 makes a dead turn around the sheave 46.1 and the sheave 46.2. According to a fifth embodiment shown in [Fig.5], the actuation of the second articulation 40 is carried out using a first electric geared motor 80 connected to the compensator 50. The motor 80 is slidably mounted relative to the chassis 10 and comprises an electrical power supply umbilical 81. According to a sixth embodiment of the invention shown in [Fig.6], the assembly 1 comprises a device 90 for inhibiting the compensator 50 by immobilizing the yoke 54. The device 90 comprises a second geared motor 91 whose output is connected to a first eccentric pad 92. The sliding of the yoke 54 is, here, guided by two rollers 93.1 and 93.2 bearing with a first face 54.1 of the yoke 54 which is opposite the second face 54.2 on which the pad 92 bears. The pulley 43 is, here replaced by a drum 143 around which the cable 44 makes a complete turn. The forces are transmitted from the cable 44 to the drum 143 by adhesion by applying the “capstan” effect. The bearing 23 receives a rotary encoder 94 arranged to measure a rotation of the gripper 20 around the axis O2. The encoder 94 and the device 90 are also connected to the control unit. The inhibiting device 90 is particularly useful for carrying out tasks that require a large amplitude of rotation of the gripper 20 around the axis O2, such as screwing operations. When a screwing operation is to be carried out, the control unit implements the following steps. In a first step, the control unit commands a rotation of the drum 143 around the axis O2 in a first direction of rotation marked SR1. This instruction consists of energizing the cable jack 41 so as to cause a movement of the screw 42 in the direction S1. In a second step, the control unit activates the inhibiting device 90. To do this, it energizes the second geared motor 91 so that the pad 92 blocks the yoke 54 by bracing.According to a third step, the control unit commands a rotation of the pulley 33 so as to reduce a tension of the cable 44 from a working tension value to a disengagement tension value. According to a fourth step, the control unit commands a rotation of the drum 143 around the second axis O2 in a second direction of rotation SR2 opposite to the first direction of rotation SR1. This instruction consists of energizing the cable jack 41 so as to cause a movement of the screw 42 in the direction S2. In the absence of tension in the cable 44, the cable 44 will slide relative to the drum 143 which remains stationary. According to a fifth step, the control unit. controls a rotation of the pulley 33 so as to restore a tension in the cable 44 which is equal to the value of the working tension. According to a sixth step, the control unit deactivates the inhibition device 90 by controlling a rotation of the second geared motor 91 so that the shoe 92 releases the yoke 54. Finally, the control unit controls a new rotation of the drum 143 in the SRI direction. The steps of the method can be repeated until the screwing operation is completed. The information from the encoder 94 is analyzed by the control unit in order to maintain the functional link which exists between the position of the screw 42 of the cable jack 41 and the angular position of the drum 143. This method makes it possible to control rotations of the gripper 20 of unlimited amplitude while the cable cylinder 41 has a limited stroke. According to a seventh embodiment shown in Figures 7 to 9, the assembly 1 also comprises a braking device 95 for selectively braking the second actuating wheel. The device 95 comprises a lever 96, the first end 96.1 of which is mounted to rotate relative to the arm 33.1 around an axis substantially parallel to the axis O2. A helical spring 97 exerts a return force in position of the lever 96 towards the drum 143. The second end 96.2 of the lever 96 is provided with a tension detection wheel 98 which is in contact with the cable 44 and a second locking shoe 99 located opposite one of the flanges 144 of the drum 143. When the tension of the cable 44 is equal to a working tension, the return force exerted by the spring 97 on the lever 96 is insufficient to cause a movement of the lever 96 and the lever 96 is in a working position in which the shoe 99 is maintained at a non-zero distance from the flange 144 ([Fig.8]). The braking device 95 is then passively deactivated by the tension of the cable 44. When the tension of the cable 44 is reduced during the third step of the above method and becomes lower than a predetermined threshold also called "clutch tension", the return force exerted by the spring 97 overcomes the tension of the cable 44 and causes the lever 96 to move towards the drum 143, which brings the shoe 99 into contact with the flange 144 ([Fig. 9]) and brakes the drum 143. The braking device 95 is then passively activated by the reduction of the tension of the cable 44 and its passage below the predetermined threshold. When the tension of the cable 44 is restored to its working value (step 5), the tension of the cable 44 increases and ends up exceeding the “clutch tension” value. The cable 44 then exerts on the wheel 98 a force greater than the return force exerted by the spring 97, which causes a movement of the lever 96 tending to move the pad 99 away from the flange 144. The braking device is then deactivated ([Fig.8]). device 90 ensures that no movement of the axis O3 of the drum 143 is possible (in other words that the function of the compensator 50 is prohibited which guarantees the constancy of the clutch tension). Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims. Especially, - although here the gripping assembly comprises a cable connected to an actuator and which acts on an actuating pulley, the invention also applies to other types of members for transmitting a lifting traction force and their associated actuators such as for example a toothed wheel which meshes with a chain, a toothed or smooth belt or a ribbon and a wheel, a hybrid member comprising connecting rods connected by cable, or any jack applying a traction force to any other type of transmission member; - although here the first axis is a pitch axis and the second axis is a roll axis, the invention also applies to a gripping assembly comprising other articulation axes such as for example a yaw axis; - although here the first actuator is a driven screw cable actuator, the invention also applies to other types of actuator such as for example a rotary actuator which drives one of the first wheels, a driving screw cable actuator; - although here the gripping assembly comprises a first and a second pulley cooperating with cables, the invention also applies to other types of wheels and elements for transmitting a traction force such as for example a toothed wheel and a chain, a drum for multi-turn winding, a drum and a ribbon, pulleys and a belt; - although here the cables are crimped onto the pulleys, the invention also applies to other methods of connecting the cables to the pulleys, such as for example a connection by adhesion or using several dead holes; - although here two sheaves return the cable to the second actuating pulley, the invention also applies to other types of return of elements for transmitting a traction force such as for example smooth shafts mounted or not to rotate relative to the chassis; - although here the articulation of the compensator shaft is achieved using a rod engaged in a bearing, the invention also applies to other types of articulated connection such as for example a cable connection whose torsional flexibility allows the articulation of the compensator shaft; - although here the first and second cables comprise a turnbuckle, the invention also applies to other types of preloading devices for an element of transmission of a tensile force such as a cable tensioner roller; - although here the second actuator is an electric geared motor, the invention also applies to other types of rotary actuators such as for example a harmonic drive type motor or a pneumatic motor; - although here the cable makes one complete turn on the drum, the invention also applies to a cable making a different number of turns on the drum, such as for example a cable making no complete turns (the adhesion tension then having to be quite strong) or two or more turns around the drum; - although here the braking device comprises a pad which comes to bear on a flange of the drum, the invention also applies to other types of braking device such as for example a lining which would be pinched on a disc secured to the second pulley and the activation and deactivation of which would be controlled by the control unit: - although here the braking device is automatically activated during the third step, the invention also applies to other types of braking devices such as controlled braking devices which can be activated at any time between steps | and 3 and deactivated between steps 5 and 7 of the method, such as for example electric or magnetic braking devices; - although here the inhibition device comprises a geared motor, the invention also applies to other types of actuators of a braking pad such as for example an electromagnet.
Claims
Claims
1. Articulated gripping assembly (1) comprising: a chassis (10) a controlled gripper (20); a first articulation (30) of the gripper (20) around a first axis (O1), the first articulation (30) being actuated by a first actuator (31) comprising a first wheel actuating (33) connected to a bearing (23) for guiding the gripper (20) rotating around a second axis (O2), the first actuating wheel (33) being driven using of a first element for transmitting a traction force (34) which collaborates with a first idler wheel (35); a second articulation (40) of the gripper (20) around the second axis (02), the second articulation (40) being actuated by a second actuator (41, 60) comprising a second actuating wheel (43) connected to the gripper (20), the second actuating wheel (43) being driven at using a second element transmitting a force of traction (44) which collaborates with a second idler wheel (45) mounted to rotate relative to the chassis (10) around a third axis (O3), in which the second articulation (40) includes a reference (46.1, 46.2) of the second element of transmission of a traction force (44) to return this last around the first axis (O1).
2. Articulated gripping assembly {1) according to claim 1, in which the second axis and / or the third axis is orthogonal to the first axis.
3. Articulated gripping assembly {1) according to claim 1 or 2, in which the second element for transmitting a traction force (44) performs a dead turn around the return (46.1, 46.2) of the second element transmission of a traction force (44).
4. Articulated gripping assembly (1) according to any one of the claims- preceding indications, in which a support (54) of the second wheel idler (45) is also mounted to rotate around a fourth axis (O4) substantially orthogonal to the third axis (03).
5. Articulated gripping assembly (1) according to any one of the claims- preceding indications, comprising a first preloading device (36) of the first element for transmitting a traction force (34) and / or a second preloading device (58) of the second element of transmission of a tractive force (44).
6. Articulated gripping assembly (1) according to any one of the claims- preceding indications, comprising a compensator (50) intended to make vary a first distance (D1) separating the third axis (03) from the first axis (O1) as a function of an angular position of the first actuating wheel (33) around the first axis (O1).
7. Articulated gripping assembly (1) according to claim 6, in which the compensator (50) comprises a shaft (51) which rotatably connects the first idler wheel (35) and a compensation wheel (52), the wheel of compensation (52) cooperating with a third transmission element of a traction force (53) which is connected to the second idler wheel (45).
8. An articulated gripping assembly according to claim 7, wherein the second preloading device of the second transmission element of a tensile force (44) comprises a preloading device (58, 71) of the third element for transmitting a tensile force (53).
9. Articulated gripping assembly according to claims 5 and 7 or 5 and 8, wherein the second preloading device of the second element for transmitting a traction force (44) comprises a device for preload of a fourth element transmitting a force of traction (72) of the second actuator (60).
10. An articulated gripping assembly (1) according to any one of the claims- indications 6 to 9, comprising a selective device (90) for inhibiting the compensator (50).
11. A gripping assembly (1) according to claim 10, comprising a braking device (95) for selectively braking the second wheel actuation (143).
12. A gripping assembly (1) according to claim 11, wherein the braking device is arranged to apply a braking force on the second actuating wheel when a tension of the second cable is below a predetermined threshold.
13. An articulated gripping assembly according to any one of the claims- preceding indications, wherein the second actuator (80) is a rotary actuator (80).
14. Articulated arm comprising a gripping assembly (1) according to one of any of the preceding claims.
15. A method of using a gripping assembly according to claim dication 10, comprising the following steps: Step |: activate the inhibition device (90); Step 2: Order a rotation of the first wheel actuating means (33) so as to reduce a voltage of the second element for transmitting a traction force (44) from a working voltage value to a voltage value of clutch; Step 3: Order a rotation of the second wheel actuating (43) around the second axis (O2) in a second direction of rotation opposite to the first direction of rotation; Step 4: Order a rotation of the first wheel actuating means (33) so as to restore a voltage of the second transmission element (44) of a traction force which is equal to the value of the working voltage; Step 5: Deactivate the inhibition device (90); Step 6: Order a new rotation of the second actuating wheel (43).
16. A method of use according to claim 15, wherein the assembly gripping device (1) comprising a braking device (95) for selecting tively brake the second actuating wheel (43), the method includes the following additional steps: a step of activating the braking device (95) located between step 1 and step 2; a step of deactivating the braking device (95) located between step 4 and step 6.