Conduction path structure of robot

A conduction path structure of a robot in which a conduction path has a simplified structure is provided. A conduction path structure of a robot includes: a structural mechanism which functions as a support and has a conductor portion; an actuator that operates the structural mechanism; and a conduction path through which driving power and/or a control signal is supplied to the actuator, wherein the conduction path also serves as the conductor portion of the structural mechanism.

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2016-236781, filed on 6 Dec. 2016, the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a conduction path structure of a robot, forming conduction paths for driving power and a control signal.

Related Art

With regard to a work robot that performs a machining operation on a work, a technology for preventing wires extending from a base end-side rotation shaft to a distal end-side rotation shaft from getting tangled is proposed (see Patent Document 1). In the technology disclosed in Patent Document 1, wires are accommodated in a housing provided in an arm member to prevent the wires from getting tangled. On the other hand, a technology of covering a caring robot arm with a flexible material to improve safety is proposed (see Patent Document 2). In the technology disclosed in Patent Document 2, a surface layer of a hand close to the distal end of the arm is covered with a flexible material.Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2009-113188Patent Document 2: Japanese Unexamined Patent Application, Publication No. H11-226062

SUMMARY OF THE INVENTION

In the technology of Patent Document 1, since wires pass through a housing provided in an arm member, it is difficult to handle the wires during assembling. Moreover, in the technology of Patent Document 2, although a predetermined portion of the robot arm is covered by a flexible material, wires connected to an actuator of the hand have to pass through the flexible material. Due to this, so-called double insulation is applied to a portion covered with the flexible material, which is redundant.

With the foregoing in view, an object of the present invention is to provide a conduction path structure of a robot, in which the conduction path has a simple structure.

(1) A conduction path structure of a robot (for example, a robot1to be described later) of the present invention is a conduction path structure of a robot including: a structural mechanism (for example, a structural mechanism100to be described later) which functions as a support and has a conductor portion (for example, conductive structural members611to613,621to623,631to633, and641to643to be described later); an actuator (for example, first, second, and third actuators31,32, and33to be described later) that operates the structural mechanism; and a conduction path (for example, first, second, and third groups of conduction paths61,62, and63to be described later) through which driving power and/or a control signal is supplied to the actuator, wherein the conduction path also serves as the conductor portion of the structural mechanism.

(2) In one aspect of the conduction path structure of the robot according to (1), the structural mechanism may further include a cover (for example, first, second, and third coating members51,52, and53to be described later) that covers an outer surface of the structural mechanism and is formed of an insulating flexible material.

(3) In one aspect of the conduction path structure of the robot according to (1) or (2), the structural mechanism may form an arm (for example, first, second, and third arms11,12, and13to be described later) of the robot in which a plurality of conductive structural members (for example, conductive structural members611to613,621to623,631to633, and641to643to be described later) as the conductor portion, serving as electrically independent conduction paths are coupled with an insulating member (for example, a structure adhesive650to be described later) interposed therebetween.

(4) In one aspect of the conduction path structure of the robot according to (3), the conduction path of the arm may form a power supply conductor that supplies an output of a power supply source (for example, a power supply4to be described later) to a motor (for example, first, second, and third motors41,42, and43to be described later) which is a driving source of the actuator.

(5) In one aspect of the conduction path structure of the robot according to (3), the conduction path of the arm may form a control signal conductor (for example, conductive structural members641to643to be described later) that supplies a control signal to the actuator.

According to the present invention, it is possible to realize a conduction path structure of a robot, in which the conduction path has a simple structure.

DETAILED DESCRIPTION OF THE INVENTION

A conduction path structure of a robot according to an embodiment of the present invention will be described with reference toFIG. 1.FIG. 1is a conceptual diagram illustrating a conduction path structure of a robot according to an embodiment of the present invention. In a robot1illustrated inFIG. 1, a first arm11which is a revolving body is provided on a base portion10, a second arm12and a second arm13are provided at the distal end of the first arm11in that order with a joint interposed therebetween, and a hand14is provided at the distal end of the third arm13with a joint interposed therebetween.

The first, second, and third arms11,12, and13form a structural mechanism100of the robot1. The structural mechanism100includes a base portion10and joints (21,22,23) to be described later in addition to the above-described components. A first joint21between the first arm11and the second arm12is operated by a first actuator31. Similarly, a second joint22between the second arm12and the third arm13is operated by a second actuator32. Furthermore, a third joint23between the third arm13and the hand14is operated by a third actuator33.

In the present embodiment, the first, second, and third actuators31,32, and33are configured using a motor as a driving source. That is, the first actuator31uses a first motor41as a driving source, the second actuator32uses a second motor42as a driving source, and the third actuator33uses a third motor43as a driving source. Driving power of each motor and a necessary control signal are supplied from a control device2to the above-described base portion10through a cable3.

The robot1of the present embodiment is a so-called cooperating robot that operates while sharing a work area with a person. In order to enhance safety when a person touch the robot1, the surfaces of the first, second, and third arms11,12, and13are covered with corresponding first, second, and third coating members51,52, and53, respectively. The first, second, and third coating members51,52, and53are covers formed of an insulating flexible material. This cover is preferably formed of a material having excellent heat-resistant and heat-insulating properties. Furthermore, the first, second, and third joints21,22, and23are also covered with a cover similar to the above-described cover. These covers may have a contact sensor on the surface thereof in order to enhance safety when a person touches the robot1.

The robot1of the present embodiment has conduction paths for supplying electric power to the first, second, and third motors41,42, and43which are the driving sources of the first, second, and third actuators31,32, and33, respectively. Particularly, in the present embodiment, these conduction paths also serve as conductor portions of the above-described structural mechanism.

That is, the structural mechanism functions as a support and has a plurality of conductor portions. The expression “functioning as a support” means that the structural mechanism in itself has sufficient rigidity and functions as a so-called skeletal portion. More specifically, the structural mechanism has arms (the first, second, and third arms:11,12, and13) to which a plurality of conductive structural members as conductor portions are coupled with an insulating member interposed therebetween. These arms (the first, second, and third arms:11,12, and13) form conduction paths in which the respective conductive structural members are electrically independent.

These conduction paths are schematically depicted by broken lines inFIG. 1. A first group of conduction paths61, a second group of conduction paths62, and a third group of conduction paths63are provided as conduction paths that supply electric power to the first, second, and third motors41,42, and43, respectively. As depicted by broken lines in the drawing, the first, second, and third groups of conduction paths61,62, and63each form a conduction path in which three conductive structural members are electrically independent.

Therefore, the first arm11includes the first group of conduction path61that supplies electric power to the first motor41, the second group of conduction paths62that supplies electric power to the second motor42, and the third group of conduction paths63that supplies electric power to the third motor and forms a conduction path in which at least nine conductive structural members in total are electrically independent.

The second arm12includes the second group of conduction paths62that supplies electric power to the second motor42and the third group of conduction paths63that supplies electric power to the third motor and forms a conduction path in which at least six conductive structural members in total are electrically independent.

The third arm13includes the third group of conduction paths63that supplies electric power to the third motor43and forms a conduction path in which at least three conductive structural members in total are electrically independent.

As described above, the arms (the first, second, and third arms:11,12, and13) have the plurality of conductive structural members coupled with an insulating member interposed therebetween and form a conduction path in which the respective conductive structural members are electrically independent. A configuration of such an arm will be described with reference toFIG. 2.

FIG. 2is a cross-sectional view illustrating an example of an arm in the conduction path structure of the robot1illustrated inFIG. 1.FIG. 2illustrates an example of the first arm11as a representative example of the arms (the first, second, and third arms:11,12, and13). As illustrated inFIG. 2, a cross-section of the first arm11is generally hollow and has an approximately square contour. An outer circumference of the first arm11is covered by the first coating member51described with reference toFIG. 1. Conductor portions that form a skeletal portion of the robot arm as a structural body are arranged inside the first arm11in an approximately square form.

Referring toFIG. 2, the corner structural members71,72,73, and74are provided at four corners of the approximately square arrangement of the structural members of the skeletal portion of the first arm11. The cross-sections of the four corner structural members71,72,73, and74have approximately the same shapes as illustrated in the drawing. As a representative example, a sectional shape of the corner structural member71has structural plates71aand71bextending by predetermined equal widths along one side and an adjacent side at right angles from a corner of the square shape and two bonding plates71cand71dbent at right angles toward the inner side of the square shape from extension edges of the structural plates71aand71b. An assembly of three conductive structural members611,612, and613that form the first group of conduction paths61is disposed between the two corner structural members71and72of the cross-section of the first arm11. That is, this assembly forms a structural member that connects the two corner structural members71and72.

The conductive structural members611,612, and613has approximately the same shape and dimensions. As a representative example, a sectional shape of the conductive structural member611includes a structural plate611ahaving a predetermined width extending along one side of the square and two bonding plates611band611cbent at right angles toward the inner side of the square from both ends of the structural plate611a. In the conductive structural members611,612, and613, opposing bonding plates of the assembly arranged in a line are bonded by an insulating structure adhesive650. Furthermore, bonding plates positioned at both ends of this assembly are bonded by the insulating structure adhesive650and the bonding plates of the corresponding corner structural members71and72. Although reference numerals are assigned to the partial structure adhesive650inFIG. 2, the insulating structure adhesive is similarly used in bonding between the bonding plates.

The structure between the two corner structural members71and72in the skeletal portion of the first arm11is similarly applied to the structure between the corner structural members72and73, the structure between the corner structural members73and74, and the structure between the corner structural members74and71. That is, an assembly of three conductive structural members621,622, and623that form the second group of conduction paths62is disposed between the corner structural members72and73, and this assembly forms a structural member that connects the two corner structural members72and73. Three conductive structural members621,622, and623are bonded by the insulating structure adhesive650and the assembly and both corner structural members72and73are bonded by the insulating structure adhesive650similarly to the corner structural members71and72.

Moreover, an assembly of three conductive structural members631,632, and633that form the third group of conduction paths63is disposed between the corner structural members73and74, and this assembly forms a structural member that connects the two corner structural members73and74. Three conductive structural members631,632, and633are bonded by the insulating structure adhesive650and the assembly and both corner structural members73and74are bonded by the insulating structure adhesive650similarly to the corner structural members71and72.

Furthermore, an assembly of three conductive structural members641,642, and643that form the fourth group of conduction paths64is disposed between the corner structural members74and71, and this assembly forms a structural member that connects the two corner structural members74and71. Three conductive structural members641,642, and643are bonded by the insulating structure adhesive650and the assembly and both corner structural members74and71are bonded by the insulating structure adhesive650similarly to the corner structural members71and72.

In the present embodiment, the conductive structural members611,612, and613that form the first group of conduction paths61, the conductive structural members621,622, and623that form the second group of conduction paths62, the conductive structural members631,632, and633that form the third group of conduction paths63, and the conductive structural members641,642, and643that form the fourth group of conduction paths64are preferably formed of a metal material having excellent mechanical strength and such high conductivity as to be suitable for electric wires such as I-go aluminum alloy wire (JEC-3405-2010), for example. All or some of the corner structural members71,72,73, and74may be formed of the above-described metal material.

The corner structural members71,72,73, and74, and the conductive structural members611to613,621to623,631to633, and641to643described for the first arm11with reference to the cross-sectional view ofFIG. 2have longitudinal lengths corresponding to approximately the entire length of the first arm11. The second and third arms12and13described with reference toFIG. 1may have configurations approximately similar to that of the first arm11described with reference to the cross-sectional view ofFIG. 2.

However, in the second arm12, a rigid member having low conductivity may be used instead of the conductive structural member of the first group of conduction paths61of the above-described first arm11. Moreover, in the third arm13, a rigid member having low conductivity may be used instead of the conductive structural member of the first and second groups of conduction paths61and62of the above-described first arm11.

Moreover, when the number of conductive structural members in the second arm12is smaller than that of the first group of conduction paths61of the first arm11, a planar structural member that integrally couples the corner structural members71and72may be used without providing the conductive structural members611,612, and613that form the first group of conduction paths61of the first arm11.

When the number of conductive structural members in the third arm13is smaller than that of the first group of conduction paths61of the first arm11, in addition to using the planar structural member as described for the second arm12, a planar structural member that integrally couples the corner structural members72and73may be used without providing the conductive structural members621,622, and623that form the second group of conduction paths62of the first arm11.

On the other hand, the second and third arms12and13may have configurations similar to that of the first arm11and electric wires may be connected to conductive structural members which are actually used as conduction paths only.

Moreover, electric connection from respective terminals (not shown) in which the ends of conductors of the cable3are fitted inside the base portion10illustrated inFIG. 1to the conductive structural members611,612, and613of the first group of conduction paths61of the first arm11can be realized using flexible bonding wires appropriately. Similarly, electric connection from the conductive structural members621,622, and623of the second group of conduction paths of the first arm11and the conductive structural members631,632, and633of the third group of conduction paths to the conductive structural members of the corresponding conduction paths of the second arm12can be realized using flexible bonding wires appropriately. Furthermore, electric connection between the corresponding conductive structural members of the corresponding conduction paths of the second and third arms12and13can be realized using flexible bonding wires appropriately.

The conductive structural members of the first, second, and third arms11,12, and13are insulated by the insulating structure adhesive650and the respective conductive structural members form electrically independent conduction paths. Moreover, the outer circumferences of the first, second, and third arms11,12, and13are covered by the first, second, and third coating members51,52, and53which are covers formed of an insulating flexible material, the arms are insulated from the outside appropriately. A cavity may be formed in a partial portion of each of the first, second, and third coating members51,52, and53, and the cavity may be used as an insertion space for bonding wires and may enhance the function as a shock absorbing material.

The first, second, and third groups of conduction paths61,62, and63among the conduction paths described with reference toFIG. 2are used for supplying electric power for driving the corresponding first, second, and third motors41,42, and43, respectively. In contrast, the fourth group of conduction paths64is used for supplying a control signal and is not particularly necessary depending on a drive control method of the motor. An example of a case where the fourth group of conduction paths64is used will be described with reference toFIGS. 4 and 5.

Next, an electric configuration of conduction paths of the conduction path structure of the robot1described with reference toFIGS. 1 and 2will be described. In the conduction path structures of the first, second, and third arms11,12, and13of the robot1, the conduction paths to the corresponding first, second, and third motors41,42, and43are similar. Therefore, the conduction path structure to the first motor41in the first arm11of the robot1will be described as a representative example.

FIG. 3is a diagram of an electrical system illustrating an example of a case in which electric power is supplied to a motor which is a driving source of an actuator by the conduction path structure of the robot illustrated inFIG. 1. InFIG. 3, the control device2converts AC electric power supplied from a three-phase AC power supply4to DC electric power with the aid of a converter202under the control of a control unit201and then converts the DC electric power to AC electric power having necessary frequency and voltage with the aid of an inverter203in the next stage. This AC electric power is supplied to the first motor41through the conductive structural members611,612, and613of the above-described first group of conduction paths61of the first arm11through the cable3.

FIG. 4is a diagram of an electrical system illustrating another example of a case in which electric power is supplied to a motor which is a driving source of an actuator by the conduction path structure of the robot illustrated inFIG. 1.FIG. 4is different fromFIG. 3in that the inverter203is disposed on a side of the first motor41, and a control signal and a DC link voltage which is an output of the converter202are supplied to the inverter203. That is, a control device2aconverts AC electric power supplied from the three-phase AC power supply4to DC electric power with the aid of the converter202under the control of a control unit201ato obtain a DC link voltage and then supplies the DC link voltage to the inverter203through the cable3and the conductive structural members611and612of the above-described first group of conduction paths61of the first arm11. Moreover, the control device2asupplies a control signal which is an output of the control unit201ato a control terminal of the inverter203through the cable3and one conductive structural member641of the fourth group of conduction paths described with reference toFIG. 2. In this way, the electric power converted to AC electric power having necessary frequency and voltage by the inverter203is supplied to the first motor41.

FIG. 5is a diagram of an electrical system illustrating still another example of a case in which electric power is supplied to a motor which is a driving source of an actuator by the conduction path structure of the robot illustrated inFIG. 1.FIG. 5is different fromFIG. 3in that the converter202and the inverter203are disposed on a side of the first motor41. In this case, a control device2bsupplies AC electric power to the converter202through the cable3and the conductive structural members611,612, and613of the above-described first group of conduction paths61. Moreover, the control device2bfunctions like the control unit201illustrated inFIG. 3and supplies a control signal to the converter202and the inverter203. Supply of the control signal through one conductive structural member641of the fourth group of conduction paths described with reference toFIG. 2is performed as will be described later with reference toFIG. 6. The electric power converted to the AC electric power having necessary frequency and voltage by the converter202and the inverter203operating in accordance with the control signal in the above-described manner is supplied to the first motor41.

FIG. 6is a system diagram of a control signal in the conduction path structure of the robot illustrated inFIG. 1and particularly illustrates a case in which the control signal is transmitted by serial communication using the conductive structural members641,642, and643of the fourth group of conduction paths64illustrated inFIG. 2. InFIG. 6, a control signal is supplied from a signal conversion circuit251to a power conversion circuit (not illustrated inFIG. 6) formed by the converter202and the inverter203illustrated inFIG. 5. The power conversion circuit operates according to an output signal of the signal conversion circuit251and driving power is supplied to the first motor41. Similarly, a signal conversion circuit252is provided in a power conversion circuit that supplies driving power to the second motor42. A signal conversion circuit253is provided in a power conversion circuit that supplies driving power to the third motor43. That is,FIG. 5illustrates a case in which a control signal is supplied from the control device2bto the first motor41(a power conversion circuit formed by the converter202and the inverter203) as a representative example. In contrast, as illustrated inFIG. 6, control signals are supplied from the signal conversion circuits252and253to the power conversion circuits of the second and third motors42and43similarly.

Specifically, a control signal is supplied to the signal conversion circuit251corresponding to the power conversion circuit (the power conversion circuit formed by the converter202and the inverter203illustrated inFIG. 5) that supplies driving power to the first motor41through one conductive structural member641among the three conductive structural members of the fourth group of conduction paths illustrated inFIG. 2. Moreover, a control signal is supplied to the signal conversion circuit252corresponding to the power conversion circuit (not illustrated) that supplies driving power to the second motor42through another conductive structural member642among the three conductive structural members of the fourth group of conduction paths illustrated inFIG. 2. Furthermore, a control signal is supplied to the signal conversion circuit253corresponding to the power conversion circuit (not illustrated) that supplies driving power to the third motor43through another conductive structural member643among the three conductive structural members of the fourth group of conduction paths illustrated inFIG. 2.

In this case, one corner structural member71among the four conductive corner structural members illustrated inFIG. 2, for example, may be applied to a common line for the three conductive structural members641,642, and643used as signal lines. In this way, the respective control signals which are serial signals from the control device2bare supplied to the corresponding signal conversion circuits251,252, and253through the three conductive structural members641,642, and643. Appropriate control is performed on the first, second, and third motors41,42, and43.

As clear from the description of the embodiment, the conduction path structure of the robot according to the present invention includes the structural mechanism100which functions as a support and has the conductor portion (the conductive structural members611,612, and613; the conductive structural members621,622, and623; the conductive structural members631,632, and633; and the conductive structural members641,642, and643); the actuator (31,32,33) that operates the structural mechanism100; and the conduction path (61,62,63,64) through which driving power and/or a control signal is supplied to the actuator (31,32,33), wherein the conduction path (61,62,63,64) also serves as the conductor portion of the structural mechanism100(the first to third arms:11,12,13). Therefore, it is possible to realize a conduction path structure of a robot in which a conduction path has a simplified structure without using additional power supply cables and the like.

The present invention is not limited to the above-described embodiment of the present invention but can be modified in various ways. For example, in the embodiment described with reference toFIG. 2, although the arm (the first arm11) of the robot has an approximately square sectional shape, the sectional shape is not limited thereto but may be a circular shape. Beside this, modifications and improvements made within a range where the object of the present invention can be attained also fall within the scope of the present invention.

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