JPS61293792A - Multi-joint type manipulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

This invention can be loaded into a nuclear reactor and used for various inspections inside the reactor. This invention relates to the configuration of an articulated manipulator intended for manipulators that perform simple repairs, etc.

[Prior art and its problems]

As mentioned above, a manipulator is inserted into the reactor, a TV camera is attached to the work unit attached to the end of the arm, and the inside of the reactor is visually inspected using a monitor, or a workpiece such as a grab mechanism is installed. 2. Description of the Related Art Articulated manipulators that perform various operations within a furnace are known. Here, the outline of the manipulator used in the above-mentioned nuclear reactor is shown in FIG. 4 is a stand pipe that penetrates the primary shield 2 and is installed on the upper surface of the pressure vessel L; 5 is a charge plate inside the reactor; 6 is a fuel control rod loaded into the reactor core through the stand pipe 4; 7 is this stand pipe; This is an articulated manipulator that is the subject of the invention. The manipulator 7 is loaded into the furnace from the floor of the secondary shield 3 through a guide pipe 8 installed in the stand pipe 4, and is remotely operated via a drive device 9 in accordance with a command given to an operation panel (not shown). be steered. Here, as is well known, the manipulator 7 constitutes a multi-jointed manipulator arm with multiple links indicated by reference numerals 7a to 7f that are interconnected in series through joints, and the rotation operation of the tip link and the operation of each link are performed. By rotating the joints between each other, the work unit 10, such as a TV camera attached to the end link 7a of the arm, is guided and moved within the furnace to perform various inspection operations. The illustration shows pressure vessel 1.
The situation inside the high-temperature gas duct la is being monitored with a TV camera. By the way, in conventional manipulators of this type, the rotation of the joints is generally driven by a hydraulic cylinder built into the link casing, but with this hydraulic drive system, control is complicated and the configuration of the hydraulic system is also complicated. This increases the size in terms of piping space, and the hydraulic cylinder used as the actuator has a large output/weight ratio and output/size ratio. In addition, when the manipulator is inserted into the furnace and extended horizontally, the weight of the work unit attached to the tip of the manipulator arm is small, while the link at the base is connected to the link further forward. In addition, since the weight of the drive mechanism of the joint between each link is cumulatively added, an extremely large drive torque is required to rotate the link, and the hydraulic cylinder installed in this link becomes increasingly large. Therefore, it is extremely difficult to construct a long articulated manipulator that can be inserted into a standpipe with a limited diameter for inspection inside a nuclear reactor. For this reason, making the manipulator lighter and more compact has become an important issue in manufacturing this type of manipulator.

[Purpose of the invention]

This invention was developed in consideration of the above points, and provides an articulated manipulator useful for inspecting the inside of a nuclear reactor, which solves the difficulties associated with the conventional hydraulic drive system, has a lightweight and compact structure, and has excellent operability. The purpose is to provide

[Key points of the invention]

In order to achieve the above object, the present invention uses an electric servo motor as the actuator of the manipulator, and also uses a gear directly coupled power transmission mechanism as the drive mechanism of the joint between the links in the arm tip side region where the load applied to the link is small. On the other hand, in the arm base area where high loads are applied to the links, a chain drive power transmission mechanism that combines a feed screw mechanism, chain, and sprocket is used as the drive mechanism for the joint between the links. It is something. In other words, by using an electric servo motor as the actuator as in the above configuration, it has improved controllability and is lighter and lighter than a hydraulic servo motor using a hydraulic drive system.
By reducing the size and using either a gear direct connection type or a chain drive type power transmission mechanism depending on the required drive torque in each area of the manipulator arm,
The link-to-link joint drive mechanism in the arm end region, which does not require high output torque, uses a direct gear-coupled power transmission mechanism to reduce weight and reduce the load on the links, while the joint drive mechanism in the arm base region By adopting a chain drive type power transmission mechanism, a high output torque drive mechanism can be constructed compactly by being housed in a small diameter link casing, and the overall structure is small in diameter and compact, and a large output/weight ratio can be obtained. It becomes possible to manufacture multi-jointed manipulators.

[Embodiments of the invention]

1 and 2 show an embodiment of the invention, and the same parts corresponding to FIG. 3 are given the same reference numerals. First of all, Figure 1 shows the low load area of the multi-stage links that make up the manipulator arm, especially the work unit 1.
This figure shows a joint drive mechanism for a joint between the distal end link 7a holding 0 and the next-stage link 7b. That is, the links 7a and 7b are hingedly connected to each other through a pin serving as a rotating shaft between the hinges lla extending from each link casing 11, and the driven side tip links 7ag, t! ! ! Casing l of moving side link 7b
A rotation drive mechanism 12 installed inside the hinge is transmission-coupled so that the hinge can be rotated in the direction of arrow A around the axis of rotation of the hinge. Here, the swing drive mechanism 12 uses an electric DC servo motor 13 as an actuator, and a clutch 14. Brake 15. It is constructed by combining a speed reduction mechanism 16 such as Harmonic Drive (trade name: manufactured by Harmonic Drive Systems) with a bevel gear 17 and a bevel gear 18 on the link 7a side directly connected to the gear 17. Note that the rear clutch 14 of the above-mentioned components is normally in a connected state, and operates to disconnect between the servo motor 13 and the driven side in an emergency, and the brake 15 operates when the servo motor 13 is stopped to disconnect the tip link 7a. It serves to maintain the position. With this configuration, the servo motor 13 drives the clutch 14 and the brake 15. The rotational driving force transmitted to the bevel gear 17 via the deceleration mechanism 16 rotates the gear 18, thereby driving the tip link 7a to pivot in the direction of the arrow around the rotation axis of the hinge. Further, the turning angle of the tip link 7a in this case is detected by a potency P meter 19 directly connected to the hinge rotation axis between the link 7a and the link 7b. By installing the potentiometer 19 directly on the hinge rotating shaft of the driven link in this manner, it is possible to accurately detect the turning angle without being affected by puncture crash between the gears 17 and 18. Although not disclosed, the link 7b in FIG. 1 has a built-in rotational drive mechanism for rotating the link casing around an axis. Further, in FIG. 1, the joint rotation drive mechanism between the link 7b and the subsequent link 7C is also constructed in the same manner as described above. D as the actuator of the joint drive mechanism as described above.
In the distal region of the manipulator arm where the C servo motor 13 is used and the load is small and high output torque is not required, a gear 17.1 is installed in the joint drive mechanism between each link.
By employing a power transmission mechanism directly connected to gears in which 8 are combined, the joint drive mechanism can be constructed to be lightweight. Next, among the multi-stage links constituting the manipulator arm, the root side region to which a high load is applied, for example, the joints between links 7c, '7d, and 7e in FIG. 3, which require high output torque, is driven. The second mechanism configuration
As shown in the figure, that is, as described above, a high load is applied to the root side region of the manipulator arm because it is necessary to support the link weight of the tip side region, and therefore, a high output torque is required of the node drive mechanism. For this reason, if we were to adopt the gear direct-coupled power transmission mechanism shown in Figure 1 for the link in the root region, the gear mechanism would have to be large in order to obtain high output torque, and the limited link casing would require a large gear mechanism. It is extremely difficult to fit within the dimensions. In this respect, according to the configuration shown in FIG. 2, the joint drive mechanism 12
is a DC servo motor 13. installed internally in the link casing 11 of the drive side link 7d. Clutch 14° Brake 15. The harmonic drive speed reduction mechanism 16 (the configuration up to this point is the same as that shown in FIG. 1) is combined with the following chain drive type power transmission mechanism. Here, the chain drive power transmission mechanism includes a gear 20 attached to the output shaft of the reduction mechanism 16, a pair of upper and lower nuts 22 fixed to a gear 21 that meshes with the gear 20, and each nut 22.
A roller chain 25 is stretched between two feed screw shafts 23 that are screwed together, and a sprocket 24 that is integrally attached to the shaft end of each feed screw shaft 23 and the hinge rotation shaft on the driven side link 7c side. It is constructed as an assembly with. By operating the servo motor 13 in this configuration, the gear 20 is rotationally driven via the output shaft of the reduction mechanism 16, and at the same time, the pair of nuts 22 are rotated in opposite directions. As a result, one of the two feed screw shafts 23 moves forward and the other moves backward to drive the roller chain 25 in a predetermined direction, and the driven link 7c is driven to rotate in the direction of arrow A via the sprocket 24. It turns out. Incidentally, the turning angle of the link 7c is detected by a potentiometer 19 directly connected to the hinge rotation axis as in FIG. 1. By adopting a chain drive type power transmission mechanism for the drive mechanism of the joint between the links for the link in the root side area of the manipulator arm, which is subjected to such a high load, the structure can be housed within the small diameter link casing 11 and the height is high. Output torque can be obtained.

【Effect of the invention】

As described above, according to the present invention, an electric servo motor is used as the actuator, and a gear-directly coupled power transmission mechanism is adopted as the drive mechanism of the joint between the links in the arm tip side region where the load applied to the link is small. On the other hand, in the arm base area where high loads are applied to the links, a feed screw mechanism and chain are used as the drive mechanism for the joints between the links. By adopting a chain drive type power transmission mechanism that combines sprockets, the required drive torque required for turning operations between the links can be obtained for each arm region from the tip to the base of the manipulator. It is possible to provide an articulated manipulator that has high practical value, especially for inspecting inside a nuclear reactor, and which can be configured to be lightweight and compact as a whole while also being able to perform the following tasks.

[Brief explanation of drawings]

1 and 2 are perspective views showing the structure of the link joint drive mechanism in the low load area and high load area of the multi-joint manipulator according to the embodiment of the present invention, respectively, and FIG. 3 is the inside of the nuclear reactor. In Figure 0, which is a schematic configuration diagram of the entire articulated manipulator in a state where it is loaded, 1: Reactor pressure vessel, 4 Nistand pipes, 7: Manipulator, 78 to 7f: Links of each stage, lo: Work unit , 11: link casing, 12: joint drive mechanism, 13: electric DC servo motor, 14: clutch, 15 brake, 16: deceleration mechanism, 17° 18: gear constituting the gear direct-coupled power transmission mechanism, 19 : Potentiometer, 22, 23: Nand and feed screw shaft constituting the feed screw mechanism, 24: Sprocket = 25: Chain, A: Turning direction of driven link. Figure 2

Claims (1)

[Scope of Claims] 1) A manipulator arm is constituted by a plurality of links connected in series, and the joints between each link are rotated through a drive mechanism built into the link casing on the driving side. In the multi-joint manipulator, an electric servo motor is used as the actuator, and a gear-coupled power transmission mechanism is used for the drive mechanism of the joint between the links in the arm tip side region where the load applied to the link is small. On the other hand, in the arm base region where high loads are applied to the links, a chain drive power transmission mechanism that combines a feed screw mechanism, chain, and sprocket is used as the drive mechanism for the joint between the links. Features an articulated manipulator. 2) A multi-joint manipulator according to claim 1, wherein a potentiometer for detecting the rotation angle of each link is directly connected to the rotating shaft on the driven side of each link.