WO1987006872A1 - Articulate structure equipped with a rotation detecting mechanism for use in an industrial robot - Google Patents

Abstract

An articulate structure which exhibits functions of detecting the rotation and transmitting the output, wherein an articulate (14) that pivotally couples two elements that rotate relative to each other is arranged at an end of an arm (10) of an industrial robot or at a robot wrist and is provided with an optical encoder (40) which detects relative rotation between the two robot elements that rotate relative to each other, and a hollow cylindrical rotor (28) which has a slit plate (50) of the optical encoder (40) is provided at an end thereof with a flange (28b) that couples the two elements which rotate relative to each other.

Description

 Description Rotation in industrial robots

 Articulated structure with detection mechanism

 The present invention relates to an articulated structure of an arm or a list of an industrial robot, in particular, by using a rotation detecting mechanism composed of an optical rotary encoder, from one robot structural element in one mince to another. A rotation detection mechanism in an industrial robot configured to form a coupling element that enables transmission of rotational output to the robot structural elements and to form a mechanism for detecting relative rotation between the robot structural elements is provided. It is related to the provided joint structure.

 , Background technology

The joint of the robot is provided with a coupling element capable of transmitting a rotational force from one robot structural element to the other robot structural element. That is, the rotation amount as the control target value is transmitted from the rotary drive source via this coupling element to the other port element from one robot element, and the other port element is moved to a desired rotational position. A control method for moving is adopted. At this time, the actual rotation amount relative to the rotation amount as the control target value, that is, the rotation amount of the transmitted element is generally detected by a rotation detector provided in the drive motor. It is not a mechanism to directly detect the actual amount of rotation of the transmitted element. Therefore, the rotation of the transmitted element Is as amount of rotation of the one hundred mark from the rotational drive source is transmitted correctly, rotation and out of the rotary drive ^source; is the structure to monitor or detect a force is adopted.

 However, the industrial robot Minjiu detects the rotation amount as the control target directly in the transmitted element, detects the difference from the target rotation amount, and accurately converts the transmitted element to the target rotation amount. In many cases, it is preferable to set the movement to the corresponding position.

 On the other hand, a conventionally known encoder for rotation detection

 There is no configuration for directly detecting the rotation amount of the zero-rotated element of the robot using a (rotary encoder). For example, an axis or a similar element used for rotation detection for the rotated element is detected from the rotated element. There is a structure in which a member is protruded and a rotary encoder is attached to this member.However, in this case, the structure of the robot joint is enlarged, or the design is changed to the outer shell of the joint to lower the joint. 5 There is a drawback in that it causes inconvenience, such as the necessity of having a structure to accommodate the Talen coder.

Disclosure of the invention

 Therefore, an object of the present invention is to provide a joint structure having a rotation detection mechanism for an industrial robot which has solved the above-mentioned disadvantages and disadvantages.

Another object of the present invention is to provide an industrial mouthpiece in which a rotary drive source for a joint can be constituted by a low-cost motor without using a rotary drive motor with a built-in 11-rotation detector.u Nimble. The present invention is directed to an articulated joint that pivotally connects two relatively rotating elements in an industrial robot, wherein the joint internally has an optical rotary that detects a relative rotation between the two relatively rotating elements. The optical rotary encoder includes an encoder, and includes a projection and light receiving means combined with one of the two relative rotation elements, and a relative rotation of the two relative rotation elements. Te, the projection is constituted by a hollow rotary element having a rotation detecting plate to cause light change in the light receiving means, said hollow rotor _said: a Sennyo flange pivotally between two relative rotary element Another object of the present invention is to provide an articulated structure provided with a rotation detecting mechanism in an industrial mouth bot, which is characterized by having; BRIEF DESCRIPTION OF THE FIGURES

 The above and other objects and features of the present invention will be described below with reference to the drawings showing embodiments and referring to the drawings, wherein FIG. FIG.

FIG. 2 is a partially enlarged sectional view showing the structure of a joint having a rotation detecting mechanism provided at one end of a horizontal arm of the industrial robot shown in FIG. BEST MODE FOR CARRYING OUT THE INVENTION Referring to FIG. 1, an industrial robot embodying the present invention has a horizontally extended arm 10 which has a hollow structure. One robot element, one end of which is At the right end of Fig. 1 there is provided an up-and-down moving cylinder of the robot-note or a joint part 12 to be connected to the robot body 8, and at the other end, that is, at the left end of Fig. 2, other arm elements 6 It is provided with a wrist joint to which a joint 14 or a robot hand (not shown) connected to 0 is pivoted. That is, the hollow arm 10 constitutes one of two relatively rotating structural elements in the structure of the robot 7. A motor 18 forming a rotary drive source is attached to the right end of the hollow arm 10 via a mounting flange 16 at the right end of the mince part 12. The motor 18 is, for example, a well-known servo motor or the like, and has no built-in rotation detector. The output shaft 18a of the motor 18 has an appropriate coupling structure, for example, wedge attachment, to the small pulley 22 supported by the rotary shaft 20 inside the mounting flange 16 protruding into the arm 10. The pulleys 22 are coupled by a structure to transmit a rotational force to the small pulleys 22. The surface rolling transmitted to the small pulley 22 is then transmitted to the large pulley 26 provided at the left end joint 14 of the arm 10 using the belt 24. The large pulley 26 is connected to a cylindrical rotor 28 described later provided on the joint 14 by an appropriate integral coupling structure such as screw fixing or wedge coupling. Numeral 8 is rotatably held around the center of the rotary bearing 30 at the left end of the hollow arm 10 via the rotary glaze 30 as described later. The cylindrical rotor 28 is formed as a hollow cylindrical structural element having a through hole 28a at the center, and a coupling flange 28b protruding downward from the arm 10 at the lower end. The other arm 60 described above is connected to the connecting flange 28b, or the connecting flange 28b itself constitutes a robot wrist element, and It is intended to be combined with hands and other working elements. In other words, the rotational force transmitted to the large pulley 26 is

According to the deceleration rate between 26 and 26, it is transmitted to other arm elements and robot hand.

 By the way, the joint provided at the left end of arm 10 together with FIG.

Referring to FIG. 2, which is an enlarged view of the joint 14, an annular joint housing 32 is attached to a lower portion of the joint 14 by mounting bolts 34. The bearing housing 36 has the same structure, and is mounted on the annular flange 32 a of the Minho housing 32 by the mounting bolt 38. The sleeve support 36 holds the rotation bearing 30 described above. Further, the annular flange-32a formed in a part of the joint housing 32 is provided with an optical mouth encoder 40, and the rotation detection incorporated in this section ί4. A main body 42 of the rotation detecting mechanism is attached to the same sleeve with respect to the center axis of the rotary bearing 30 by an appropriate fixing method such as an adhesive method. It has an upper jaw 44 and a lower jaw 46 forming an annular space therein. The upper jaw 44 has a built-in projector 48 a of an optical rotary encoder 40, and the lower jaw 4 For example, a light receiver 48b for receiving light from the light emitter 48a is held toward the annular space. An optical rotary encoder 40 fixedly mounted on the outer periphery of the cylindrical rotator 28 interposed between the light emitter 48a, the light receiver 48b, and the two. The slit plate 50 constitutes a rotation detecting mechanism, and detects the rotation amount of the cylindrical rotor 28 having the slit plate 50. , And the floodlight The principle of optical rotation detection of the optical mouth encoder 40, which is composed of a detector 48a, a receiver 48b, and a cylindrical rotor having a slit plate 50, is generally used. Although this is no different from the rotary encoder of this type, the configuration incorporated in the joint of the mouth port is a novel structure, and the slit in the optical rotary encoder 40 is also new. A major feature is that the cylindrical rotor 28 having 扳 50 forms an output flange element in the joint of the robot.

 The optical one-time encoder 40 is covered by a cover 52, which is fixed to the joint housing 32 by mounting screws 53, and has a dust-proof seal 54 on its inner periphery. Is attached to prevent dust from entering the encoder. A nut 56 is a holding nut for the rotary bearing 30 that is screwed around the outer periphery of the cylindrical rotor 28.

 Further, the signal transmission / reception line 58 of the optical mouth encoder 40 described above passes through the cover 52, passes through the internal space of the horizontal hollow arm 10, and passes through the robot body 8 that has been lifted. It is designed to extend outside the robot body.

The above configuration, according to the robot _y bets articulated structure provided with the rotation detecting mechanism of the present invention, constituting a rotary drive source motor one motor 1 8 or et outputted rotation output is small pulley 2 2, Bell G and a large pulley 26 are transmitted to the cylindrical rotor 28, which is an output flange element, and its rotation output is detected by measuring the amount of rotation of the cylindrical rotor 28 itself, which is the element to be rotated. Directly by the optical rotary encoder 40, where the rotor 28 is an integral part of the component It forms a so-called full-closed control system that detects and feeds back the detection signal via a signal line 58 to control the rotation of the motor 18. It is clear that the so-called semi-closed control system was configured, which detects the amount of rotation and controls its own rotation, and does not detect the amount of rotation of the output flange, which is the element to be rotated. There is a difference. In other words, in the control principle, a system in which the controlled variable is directly compared with the target value and the controlled variable is corrected based on the difference value has been achieved in the robot joint structure. Is a

 As can be understood from the above description, according to the present invention, the rotation of the joint of the robot is detected by the optical encoder incorporated in the joint, and the output signal of the joint is obtained from the operation. The accuracy of rotation control of the rotary encoder has been further improved, and the optical rotary encoder has been mass-produced as a sigma-bot component in advance, so that a motor with a built-in rotary encoder can be used as the rotation drive source. In addition, the price of robots can be reduced. If the present invention is applied to the joint structure of a dustproof robot that is recently widely used, it is possible to improve the working accuracy of the mouth bot in processing and assembling precision parts using in the manufacturing process of electronic components such as semiconductors. The effect of improving is also obtained. In addition, as is clear from the configuration of the embodiment, the through hole 28a of the output flange having a hollow structure is provided with another robot element attached to the output flange and further with the other robot element. Needless to say, it can be used as a piping space for arranging a supply pipe for electrical wiring and control pressure to an element provided at the tip of the mouth bot element.

Claims

The scope of the claims  1. In a section of an industrial robot in which two relatively rotating elements are pivotally connected to each other, the joint has an optical rotary connector inside which detects relative rotation between the two relative rotating elements. The optical rotary encoder includes: a projection and a light receiving unit coupled to one of the two relative rotation elements; and the optical rotary encoder according to the relative rotation of the two relative surface rotation elements. A hollow rotor having a rotation detecting plate for causing a change in light reception in the light emitting and receiving means.The hollow surface rotator further pivotally connects the two relative rotating elements to output. An articulated structure provided with a rotation detection mechanism for an industrial robot, which has a surrounding flange for transmitting.  2. The industrial robot has one rotation drive source that generates relative rotation between the two relative rotation elements, and the connection flange that the hollow rotor of the optical rotary encoder has 2. The joint according to claim 1, further comprising: means for transmitting a rotational force from the rotary drive source to one of the two relative rotary elements. Construction.  3. The joint structure provided with a rotation detecting mechanism in an industrial robot according to claim 1, wherein one of the two relative rotation robot elements comprises an upper arm of the robot and the other comprises a lower arm of the robot. . 4. The method according to claim 1, wherein one of the two relative rotation robot elements is a robot wrist at the tip of the arm of the robot, and the other is a working element including a hand of the mouth robot. A joint structure equipped with a rotation detection mechanism for industrial robots. 5. The hollow rotor of the optical rotary encoder is mounted via a rotary bearing to one of the two relative rotating elements to which the light emitting and receiving means are coupled. 2. A joint structure provided with a rotation detection mechanism in the industrial robot according to item 1.