Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/08—Programme-controlled manipulators characterised by modular constructions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J17/00—Joints
  • B25J17/02—Wrist joints
  • B25J17/0241—One-dimensional joints
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
  • B25J19/02—Sensing devices
  • B25J19/021—Optical sensing devices
  • B25J19/025—Optical sensing devices including optical fibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
  • B25J9/12—Programme-controlled manipulators characterised by positioning means for manipulator elements electric

Definitions

• Robot joint and robot comprising such joints.
• the present invention relates to robots or manipulators and, more particularly, the articulations between two arms of such a manipulator.
• Robotic systems have been designed comprising one or more central computers and a set of "intelligent" peripherals each having their own function in the system: exteroceptive sensors (proximity sensors, rangefinders, force sensors, etc.), sensory sensors (vision machines, tactile sensors, etc.), among others. Research has been done on both hardware and software to improve the overall reaction performance of a system.
• the present invention relates to a robot articula ⁇ tion intended to achieve a relative rotation of two consecutive robot arms, characterized in that it comprises a sealed enclosure constituted by two half-shells each secured to the end of a arm and mounted in rotation 1 'over one another with the interposition of a dynamic seal, one of the two half-shells contains a brushless DC electric gearmotor and the other half-shell is driven by said gearmotor, said enclosure is filled with an electrically insulating liquid, each half-shell comprises a connector fixed on one of its external faces and intended to receive a connection cable comprising both supply conductors and a data transmission line and connected to the neighboring articulation, and said enclosure contains a gearmotor control device which comprises a processor and which operates automatically. ome as a function of the data received from the other joints and of a centralized command via the data transmission lines.
• the invention therefore makes it possible to very greatly reduce the number of connecting cables between the various articulations since the connecting cable only comprises supply conductors and the data transmission lines, ie for example five conductors.
• the use of a geared motor unit comprising a brushless direct current electric motor also makes it possible to improve the reliability of the device.
• the insulating liquid provides good cooling of the entire joint.
• the data transmission lines are optical fiber lines.
• the optical fibers are made of silica.
• the data transmission lines connect two neighboring articulations and the enclosure contains a data retransmission circuit connected between the two connectors; this retransmission device performs signal regeneration and error management.
• This arrangement makes it possible to obtain a modular structure for each of the joints.
• the enclosure comprises a device for optical coding of the movement of the geared motor and the insulating liquid is transparent.
• the processor used in the geared motor control device is a microcoded processor comprising a task scheduler with priorities, a fast memory and four communication systems per link, that is to say a processor of the type designated by "transputer ".
• the invention also relates to a robot comprising a centralized control unit and a succession of arms connected together by a joint of the type described above.
• the last arm has an effector at its end. It can also include a video camera at its end.
• a download is made of the processor of each joint.
• FIG. 1 is a side view of two consecutive arms of a robot having a hinge according to the invention
• - Figure 2 is a top view corresponding to Figure 1;
• FIG. 3 is an electrical and electronic diagram of a joint according to the invention.
• FIG. 4 is a sectional view of a joint according to the invention.
• FIG. 5 shows schematically a variant of embodiment of the invention.
• FIG. 1 shows two consecutive robot arms 1 and 2 which are mounted in relative rotation one on the other at their ends around a vertical axis 3 by means of an articulation designated under the general reference 4.
• the robot comprises several successive shafts articulated in the same way, which makes it possible to obtain any movement of the end of the last arm.
• each articulation comprises two connectors, an upstream connector 5 and a downstream connector 6.
• Each connector receives a connection cable 7 which is advantageously placed in the arm 1 or 2; this connecting cable achieves a connection between two neighboring joints; it includes supply conductors and a data transmission line.
• this cable comprises three supply conductors and two optical fibers made of silica constituting a data transmission line.
• This composite cable has a polyurethane sheath. Its speed can be 20 megabits per second.
• FIG. 3 is an electrical and electronic diagram of the articulation 4. This figure shows the upstream 5 and downstream 6 connectors which constitute interfaces; these connectors include three terminals connected to alternating current supply conductors two active conductors 11 and 12 and a ground conductor 13. This is for example a supply whose voltage is from 100 to 250 V and the frequency from 50 to 400 Hz.
• the upstream connector 5 comprises a device for connecting two optical fibers 14 and 15 which are connected to an optical fiber interface 16.
• the downstream connector 6 comprises a second optical fiber interface 17 which is connected to two optical fibers 18 and 19, which are connected to the downstream connecting cable. It is possible to provide protection against faults, such as a fuse 10, for example on the output supply conductors of the downstream connector.
• the active supply conductors 11 and 12 are connected between the two connectors 5 and 6; moreover, they supply a supply device 21 intended in particular to supply the supply of the electric motor.
• Each articulation comprises a brushless DC motor 22 whose rotation is controlled and controlled by an electronic control device which essentially comprises a processor 23 of the type commercialized under the name "transputer" by the company IN OS and which essentially comprises a microcoded processor comprising a core architecture with few instructions, for example 32, which is used for implantation simple sequential programs.
• This processor includes internally a task scheduler with priorities, microcoded, to distribute the time of the central unit between different processes.
• this processor has several asynchronous quick links, for example four.
• the internal structure of this processor therefore comprises a main processor, a fast memory and four communication systems per link.
• This processor 23 receives the signals supplied by the optical interface 16 and by the interface 17 and it constitutes, for the upstream and downstream data transmission lines, a signal retransmission device which performs error management and performs signal regeneration. which are retransmitted. It therefore constitutes a relay for the data which must be transmitted from the articulation situated upstream to that situated downstream and vice versa.
• the motor 22 is a brushless direct current motor of known type which comprises for example a three-phase winding and a permanent magnet rotor. As indicated above, this motor is supplied by a supply circuit 21 which supplies a control circuit 24 which sends a pulse current to each of the windings. In accordance with the invention, the pulses supplied by the circuit 24 are controlled by the processor 23 which directly controls the power interrupters of the circuit 24.
• the processor 23 receives via a bus 25 information relating to the position of the gearmotor and the torque supplied by the gearmotor.
• the position of the gearmotor is coded by an absolute encoder 26 of the optical type, the data of which are managed by an encoder interface 27 connected to the bus 25.
• the device also includes a torque sensor 28 which is connected to a torque controller 29 itself connected to the bus 25.
• the encoder 26 and the sensor 28 provide digital data, for example coded on twelve bits.
• the bus 25 is a 32-bit bus.
• Figure 4 is a sectional view of an articula ⁇ tion according to the invention. It essentially consists of two cylindrical half-shells which are mounted in rotation one on top of the other around their axis of revolution.
• the upstream part which is located on the right of the figure, comprises a half-shell 31 and the downstream part comprises a half-shell 32 which is rotatably mounted on the half-shell 31 by means of a bearing 33 which is associated with a dynamic seal 34.
• the two half-shells 31 and 32 each have a cover 35 respectively 36 which is fixed in a sealed manner.
• the assembly of the two shells therefore forms a sealed enclosure in which the active elements of the joint are arranged, the empty spaces being filled with a transparent dielectric liquid such as a silicone oil.
• the essential element of the articulation is constituted by a geared motor assembly comprising a brushless direct current electric motor, the stator 37 of which is integral with the upstream half-shell 31.
• the rotor 38 of this motor drives, hand, the primary part a reduction gear 41 and, on the other hand, a hollow shaft 39 secured to a fine encoder 45.
• the secondary reducing shaft 42 is secured to the downstream half-shell 32 and drives a slow shaft 43 which is arranged inside the rapid hollow shaft 39 and opens into the upstream half-shell 31.
• a gros ⁇ sier encoder 14 of absolute optical type On the slow shaft 43 is arranged a gros ⁇ sier encoder 14 of absolute optical type.
• the two encoders placed side by side are arranged in the upstream half-shell.
• All the electronic circuits are arranged on printed circuit boards which are in the form of washers and arranged around the hollow shaft 39 in a space 46 disposed between the encoders 44 and 45 and the electric motor itself, this makes it possible to limit the size of the joint.
• Each half-shell has a connector 47 respectively 48.
• the arms 1 and 2 are mounted on the connectors 47 and 48 with the interposition of a seal 49.
• the brushless electric motor is a direct current motor of the sealed type and comprising radiators.
• the use of such an engine makes it possible to very clearly improve the reliability and the maintenance of such a joint.
• the entire enclosure is maintained in a bath of dielectric liquid which is under pressure with the external pressure so as to obtain correct operation of the dynamic seal. This arrangement makes it possible to obtain good cooling of the joint and good sealing; as indicated above, this liquid is transparent so as to allow the use of optical motor position encoders.
• the motor position coding device comprises a fine coder 45 secured to the shaft 39 linked to the motor and a coder coarse 44 integral with the slow shaft 43. Both are absolute optical coders and the combination of their signals makes it possible to obtain a coding equivalent to that obtained with a fifteen bit coder which would be mounted on the reduction shaft.
• processors of the "transpu ⁇ ter” type make it possible to obtain an "intelligent" articulation; in fact, each of the buses arranged between two arms transmit information coming from a central control unit as well as from each of the articulations. Each processor can therefore control the geared motor as a function of the information received both from the central control unit and from the other articulations.
• the processor does not only constitute a relay between the various buses of the robot but it develops messages concerning its articulation which are sent to the entire system.
• the invention therefore makes it possible to produce modular articulations which can be assembled one behind the other between robot arms.
• the last arm may include an effector or a positioning tracking device such as a video camera.
• the last arm has at its end a processor which controls the effector or the locating device and provides messages on the bus arranged in this last arm.
• FIG. 5 schematically represents an embodiment in which the two arms are aligned and rotate around the same axis, namely the axis of revolution of the two half-shells.
• the two connectors are arranged on the side walls of two half-shells.
• the two connectors are arranged on the covers of the two half-shells.
• the invention makes it possible to produce robots or manipulators comprising several arms in which the expenditure on connecting cables and on connectors is reduced.
• optical fiber data transmission lines makes it possible to avoid signal interference and, in the particular case of silica fibers, this allows use in radioactive media.
• a processor of the "transputer” type simplifies the control circuit of the gearmotor and provides an intelligent articulation.
• the use of a closed enclosure filled with a dielectric liquid makes it possible to improve the cooling of the joint.

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• Engineering & Computer Science (AREA)
• Robotics (AREA)
• Mechanical Engineering (AREA)
• Manipulator (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9434496

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (5)

• 1992
  • 1992-10-13 FR FR9212238A patent/FR2696670B1/fr not_active Expired - Fee Related
• 1993
  • 1993-10-11 WO PCT/FR1993/001003 patent/WO1994008760A1/fr active Application Filing
  • 1993-12-04 TW TW82110319A patent/TW252942B/zh active

Patent Citations (5)

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