Telescopic-type robot arm and method for driving the same

Abstract

To provide a telescopic-type robot arm large in bending amount and reduced in weight, and a method for driving the same.SOLUTION: A telescopic mechanism 2 includes an outer cylinder 21 fixed to a base 1, an inner cylinder 22 provided with a camera 3, and an intermediate cylinder 23, 23' between the outer cylinder 21 and the inner cylinder 22. A wire (rope) 4-1 is passed through guide mechanisms 21b, 23b, 23b', and 22b provided at the tips of the outer cylinder 21, the intermediate cylinder 23, 23', and the inner cylinder 22; one end of the wire 4-1 is wound on a bending actuator 5-1a provided in the base 1; and the other end of the wire 4-1 is wound on a bending actuator 5-1b provided in the base 1. Spherical stoppers 8-1, 8-2, and 8-3 that have different diameters are formed on the wire 4-1. The diameters D1, D2, and D3 of the spherical stoppers 8-1, 8-2, and 8-3 are gradually larger from the bending actuator 5-1a toward the bending actuator 5-1b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a telescopic robot arm and a driving method thereof. [Background technology]

[0002] A robot arm is needed as a camera drive device to observe molten nuclear fuel in a nuclear power plant after a severe accident.

[0003] FIG. 7 is a front view showing a conventional telescopic robot arm in a stored state (see FIGS. 8 to 14 of Patent Document 1).

[0004] In Figure 7, an outer tube 21 is fixed to a base 1 having a built-in control unit (not shown), an inner tube 22 is inserted into the outer tube 21, and intermediate tubes 23, 23', 23" are inserted between the outer tube 21 and the inner tube 22. A camera 3 is provided at the tip of the inner tube 22. In Figure 7, there are three intermediate tubes 23, 23', 23", but the number can be one, two, four or more. The outer cylinder 21, intermediate cylinder 23, 23', 23" and inner cylinder 22 form a telescopic mechanism 2 which becomes thinner towards the tip, and which extends and retracts in a linear manner in the radial direction R due to an extension actuator (motor, wire drive, oil / pneumatic cylinder, etc.) not shown which is fixed inside the base 1. One ends of wires (ropes) 4-1, 4-2, 4-3 are fixed to the tips of the inner cylinder 22 and the intermediate cylinder 23, 23', 23", and the other ends of the wires 4-1, 4-2, 4-3 are wound around bending actuators (motors) 5-1, 5-2, 5-3 which are fixed inside the base 1, so that the tension of the wires 4-1, 4-2, 4-3 is adjusted by the bending actuators 5-1, 5-2, 5-3.

[0005] Further, the outer cylinder 21 is supported on the support rod 6 by an actuator (not shown) so as to be rotatable in the angular direction θ, and the support rod 6 is supported on the moving base 7 by an actuator (not shown) so as to be rotatable in the angular direction φ.

[0006] Furthermore, in order to guide the wires 4-1, 4-2, 4-3, guide mechanisms 21a, 23a, 23'a, 23"a (see FIG. 8) are provided in the outer cylinder 21 and the intermediate cylinders 23, 23', 23". In this case, the guide mechanism 21a has three pulleys (see FIG. 9) for each of the wires 4-1, 4-2, 4-3, whereas the guide mechanisms 23a, 23'a, 23"a have one pulley (see FIG. 9) for each of the wires 4-1, 4-2, 4-3. Note that it is sufficient that the guide mechanisms are provided in the outer cylinder 21 and at least one of the intermediate cylinders 23, 23', 23".

[0007] FIG. 8 is a front view showing the deployed state of the telescopic robot arm of FIG. 7, where (A) shows the unbent state and (B) shows the bent state.

[0008] First, referring to FIG. 8(A), when the telescopic mechanism 2 is deployed by linear movement in the radial direction R by an extension and contraction actuator (not shown) built into the base 1, each cylinder 21, 23, 23', 23", 22 of the telescopic mechanism 2 structurally forms a cantilever mechanism, so that the robot arm can maintain a horizontal or oblique posture without consuming power. At this time, the wires 4-1, 4-2, 4-3 are positioned along the outer cylinder 21, intermediate cylinder 23, 23', 23", and inner cylinder 22 of the telescopic mechanism 2 by guide mechanisms 21a, 23a, 23'a, 23"a.

[0009] Next, referring to FIG. 8 (B), when the wire 4-1 is wound up by the bending actuator 5-1, the wire 4-1 generates a bending moment on the intermediate tube 23, 23', 23" by folding back from the guide mechanism 21a to the guide mechanisms 23a, 23'a, 23"a, and as a result, the intermediate tube 23, 23', 23" also bends significantly upward. In addition, the wire 4-1 generates a bending moment on the inner tube 22 by folding back from the guide mechanism 21a to the inner tube 22, and as a result, the inner tube 22 also bends significantly upward. In other words, the intermediate tube 23, 23', 23" and the inner tube 22 all bend significantly upward. Therefore, the overall displacement of the robot arm can be increased.

[0010] FIG. 9 is a diagram showing the relationship between the wires and the guide mechanisms in FIGS.

[0011] As shown in FIG. 9, the wire 4-1 is wound around a pulley 23a-1 of a guide mechanism 23a fixed to the intermediate cylinder 23 from the bending actuator 5-1, and wound around a pulley 21a-1 of a guide mechanism 21a fixed to the outer cylinder 21, and then wound around a pulley 21a-1 of the guide mechanism 21a, and then wound around a pulley 23'a-1 of a guide mechanism 23'a fixed to the intermediate cylinder 23', and wound around a pulley 21a-2 of a guide mechanism 21a fixed to the outer cylinder 21, and then wound around the pulley 21a-2 of the guide mechanism 21a, and then wound around the pulley 23'a-1 of the guide mechanism 21a, and then wound around the pulley 21a-2 of the guide mechanism 21a, and then wound around the pulley 23'a-2 of the guide mechanism 21a, and then wound around the pulley 23'b of the guide mechanism 21a. The wire 4-1 is folded back from the pulley 21a-2, then folded back around the pulley 23"a-1 of the guide mechanism 23"a fixed to the intermediate tube 23", wound around the pulley 21a-3 of the guide mechanism 21a fixed to the outer tube 21, and finally folded back from the pulley 21a-3 of the guide mechanism 21a before being fixed to the tip of the inner tube 22. In other words, the wire 4-1 is folded back midway between the guide mechanism 21a and the guide mechanisms 23a, 23'a, and 23"a from the bending actuator 5-1, and finally fixed to the tip of the inner tube 22.

[0012] Similarly, the wire 4-2 in FIG. 8 is folded back from the bending actuator 5-2 between the guide mechanism 21a and the guide mechanisms 23a, 23'a, and 23"a and fixed to the tip of the inner tube 22, and the wire 4-3 in FIG. 8 is folded back from the bending actuator 5-3 between the guide mechanism 21a and the guide mechanisms 23a, 23'a, and 23"a and fixed to the tip of the inner tube 22.

[0013] In this way, the guide mechanism 21a fixed to the outer cylinder 21 has 3×3 (=9) pulleys, and the guide mechanisms 23a, 23'a, 23''a fixed to the intermediate cylinders 23, 23', 23'' have three pulleys.

[0014] In this way, in the conventional telescopic robot arm shown in Figure 7, the intermediate tubes 23, 23', 23" and the inner tube 22 bend. In particular, the bending moment at the base side, which is thicker and less likely to bend, is large, and the bending moment at the tip side, which is thinner and more likely to bend, is small, so that the tube bends evenly and greatly from the base side to the tip side. As a result, the displacement amount of the entire robot arm can be increased. Also, by gradually decreasing the bending moments of the base side intermediate tubes 23, 23', 23" toward the intermediate tubes closer to the tip, and making the bending moment of the tip side inner tube 22 the smallest, buckling of the tip side inner tube 22 can be prevented. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] JP 2019-961 A (Patent No. 6934244 A) [Patent Document 2] JP 2018-187733 A (Patent No. 6904558 A) Summary of the Invention [Problem to be solved by the invention]

[0016] However, in the conventional telescopic robot arm shown in Fig. 7, there are many pulleys and many turns of the wire, so there is a problem that the tension cannot be transmitted to the tip. To solve this problem, the diameter of the pulley must be increased to increase the efficiency of transmitting the wire tension. As a result, there is a problem that the telescopic robot arm becomes larger in the radial direction of the arm outer cylinder. [Means for solving the problem]

[0017] In order to solve the above-mentioned problems, the telescopic robot arm of the present invention includes a base, an outer tube fixed to the base, an inner tube inserted into the outer tube, at least one intermediate tube inserted between the outer tube and the inner tube, a first guide mechanism provided at a tip of the outer tube and a tip of the intermediate tube and having first and second holes, a second guide mechanism provided at the tip of the inner tube, an extension actuator provided within the base for interlockingly deploying the intermediate tube and the inner tube relative to the outer tube, first and second bending actuators provided within the base for bending the intermediate tube and the inner tube relative to the outer tube, and a wire extending from the first bending actuator through a first hole of the first guide mechanism of the outer tube and a first hole of the first guide mechanism of the intermediate tube, folded back at the second guide mechanism of the inner tube, passing through a second hole of the first guide mechanism of the intermediate tube and a second hole of the first guide mechanism of the outer tube, and extending to the second bending actuator. the diameters of the stoppers become successively smaller from the second bending actuator to the first bending actuator; the diameters of the first hole of the first guide mechanism of the outer cylinder and the diameters of the first hole of the first guide mechanism of the intermediate cylinder are smaller than the maximum diameter of the stoppers; the diameters of the second hole of the first guide mechanism of the outer cylinder and the diameters of the second hole of the first guide mechanism of the intermediate cylinder are larger than the maximum diameter of the stoppers; the first hole of the first guide mechanism of the outer cylinder does not allow the stoppers to pass through, the first hole of the first guide mechanism of the intermediate cylinder allows at least one of the stoppers to pass through but does not allow another one of the stoppers on the second bending actuator side to pass through; and the length of the intermediate cylinder is greater than the distance between a stopper that has passed through the first hole of the first guide mechanism of the intermediate cylinder and a stopper adjacent to the stopper that cannot pass through the first hole.

[0018] In addition, the driving method of the above-mentioned telescopic robot arm includes a bending preparation deployment process in which the intermediate tube and the inner tube are deployed in conjunction with each other relative to the outer tube by the telescopic actuator, and the first and second bending actuators pay out a wire to completely deploy the tube, and then wind it up on the second bending actuator to stop the stopper on the first bending actuator side of the multiple stoppers halfway on the inner tube, and an inner tube / intermediate tube bending process in which, after the bending preparation deployment process, the second bending actuator further pays out the wire and winds it up on the first bending actuator to bend the inner tube and the intermediate tube. Effect of the Invention

[0019] According to the present invention, a bending moment is generated in the intermediate cylinder and the inner cylinder by the stopper fixed to the wire, so that the number of pulleys can be reduced and the wire does not have to be folded back, thereby making it possible to reduce the size of the telescopic robot arm in the radial direction of the outer cylinder. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a front view showing a stored state of a first embodiment of a telescopic robot arm according to the present invention. [Diagram 2] FIG. 2 is a diagram for explaining a method of fixing the spherical stopper in FIG. 1 to a wire (rope). [Diagram 3] 2A and 2B are diagrams showing the relationship between the wire and the guide mechanism in FIG. 1, in which (A) is an oblique view of the telescopic mechanism in the deployed state, (B) is an oblique view and a cross-sectional view of the guide mechanism of the outer tube in (A), (C) is an oblique view and a cross-sectional view of the guide mechanism of the intermediate tube in (A), (D) is an oblique view and a cross-sectional view of the guide mechanism of the intermediate tube in (A), and (E) is an oblique view and a cross-sectional view of the guide mechanism of the inner tube in (A). [Figure 4] FIG. 2 is a front view for explaining a driving method of the telescopic robot arm of FIG. 1, where (A) shows a bending preparation deployment process, (B) shows an inner tube bending process, (C) shows a first intermediate tube bending process, and (D) shows a second intermediate tube bending process. [Diagram 5]A front view for explaining a driving method of a telescopic robot arm of a first modified example, where (A) shows a bending preparation deployment process, (B) shows an inner tube bending process, (C) shows a first intermediate tube bending process, and (D) shows a second intermediate tube bending process. [Figure 6] 13A and 13B show a telescopic robot arm according to a second modified example, in which (A) is a front view of the unfolded state, and (B) is a perspective view of the guide mechanism of (A). [Figure 7] FIG. 1 is a front view showing a conventional telescopic robot arm in a stored state. [Figure 8] 8A and 8B are front views showing the unfolded state of the telescopic robot arm of FIG. 7, where (A) shows the unbent state and (B) shows the bent state. [Figure 9] FIG. 9 is a schematic diagram of the wire and guide mechanism of FIGS. 7 and 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 is a front view showing a telescopic robot arm according to an embodiment of the present invention in a stored state.

[0022] 1, similar to the telescopic robot arm in FIG 7, the telescopic mechanism 2, which becomes thinner towards the tip, has an outer cylinder 21 fixed to a base 1, an inner cylinder 22 in which a camera 3 is provided, and intermediate cylinders 23, 23' between the outer cylinder 21 and the inner cylinder 22. In this case, there are two intermediate cylinders, but the number can be one, three or more.

[0023] A wire (rope) 4-1 is passed through guide mechanisms 21b, 23b, 23'b, 22b provided at the tips of the outer tube 21, the intermediate tube 23, 23' and the inner tube 22, and one end of the wire 4-1 is wound around a bending actuator (motor) 5-1a provided in the base 1, and the other end of the wire 4-1 is wound around a bending actuator (motor) 5-1b provided in the base 1. As a result, the tension and length of the wire 4-1 are adjusted by the two bending actuators 5-1a, 5-1b.

[0024] 7, the telescopic mechanism 2, which becomes thinner toward the tip, extends and retracts linearly in the radial direction R by an actuator (motor, hydraulic / pneumatic cylinder, etc.) (not shown) for extension and retraction that is fixed inside the base 1. The outer cylinder 21 is supported by the support rod 6 so as to be rotatable in the angular direction θ by an actuator (not shown), and the support rod 6 is supported by the movable base 7 so as to be rotatable in the angular direction φ by an actuator (not shown).

[0025] Spherical stoppers 8-1, 8-2, and 8-3 with different diameters are formed on the wire 4-1. The diameters D1, D2, and D3 of the spherical stoppers 8-1, 8-2, and 8-3 are successively larger from the bending actuator 5-1a toward the bending actuator 5-1b. That is, D1 <D2<D3 The wire (rope) 4-1 is made of a lightweight, high-strength, low-friction coefficient material wire (rope) made of high-strength chemical fiber having high breaking strength and high rigidity, which contributes to weight reduction (see Patent Document 2).

[0026] FIG. 2 is a diagram for explaining a method of fixing the spherical stoppers 8-1, 8-2, and 8-3 in FIG. 1 to the wire 4-1.

[0027] As shown in Fig. 2(A) and (B), there is a method of passing the wire 4-1 through a spherical stopper 8-1 (8-2, 8-3) in which a hole 8a has been formed in advance and winding it once or multiple times. As shown in Fig. 2(C), there is a method of winding the wire 4-1 once or multiple times around a cylinder 8b inside a spherical stopper 8-1 (8-2, 8-3) divided into two pieces, and bonding the two pieces of the spherical stopper 8-1 (8-2, 8-3). As shown in Fig. 2(D) and (E), there is a method of passing the wire 4-1 through a spherical stopper 8-1 (8-2, 8-3) in which a hole 8a has been formed in advance and forming knots 4a and 4b of the wire 4-1 at both ends of the spherical stopper 8-1 (8-2, 8-3). Still another method is to pass the wire 4-1 through a spherical stopper 8-1 (8-2, 8-3) with a hole 8a formed in advance, and then crimp the wire 4-1, as shown in FIG. 2(F). Still another method is to unravel the wire 4-1 to form a space in the wire 4-1, insert the spherical stopper 8-1 (8-2, 8-3) inside, and pull it to store the spherical stopper 8-1 (8-2, 8-3) in the wire 4-1, as shown in FIG. 2(G). Still another method is to fit a ball 8a' into the wire 4-1 with the spherical stopper 8-1 (8-2, 8-3) of FIG. 2(G) stored in it, as shown in FIG. 2(H). In this case, the ball 8a' is, for example, a hollow ball split into two.

[0028] Fig. 3 is a diagram showing the relationship between the wires and the guide mechanism in Fig. 1, where (A) is a perspective view of the telescopic mechanism 2 in an expanded state, (B) is a perspective view and a cross-sectional view of the guide mechanism 21b of the outer tube 21 in (A), (C) is a perspective view and a cross-sectional view of the guide mechanism 23b of the intermediate tube 23 in (A), (D) is a perspective view and a cross-sectional view of the guide mechanism 23'b of the intermediate tube 23' in (A), and (E) is a perspective view and a cross-sectional view of the guide mechanism 22 of the inner tube 22 in (A). As shown in Fig. 2(A), the lengths of the intermediate tubes 23, 23' and the inner tube 22 in the expanded state are L1, L2, and L3.

[0029] As shown in (B), (C), (D), and (E) of FIG. 3, the guide mechanisms 21b, 23b, 23'b, and 22b have, at their lower portions, cylinder holes 31, 32, 33, and 34 for connecting the outer cylinder 21, the intermediate cylinder 23, 23', and the inner cylinder 22. The diameters d1, d2, d3, and d4 of these holes are set to match the diameters of the outer cylinder 21, the intermediate cylinder 23, 23', and the inner cylinder 22, as follows: d1>d2>d3>d4 These have a relationship of

[0030] As shown in (B), (C), and (D) of FIG. 3, the central portion of each of the guide mechanisms 21b, 23b, and 23'b is provided with wire holes 41, 42, and 43 having the same diameter D for passing the wire 4-1 from the bending actuator 5-1b. The diameter D is the same and large enough to allow the spherical stoppers 8-1, 8-2, and 8-3 to pass through. D1 <D2<D3<D and is larger than the maximum diameter D3 of the spherical stoppers 8-1, 8-2, and 8-3. Therefore, when the robot arm expands or contracts, the wire 4-1 can be wound up by the bending actuator 5-1b, so that the wire does not bend and the spherical stoppers 8-1, 8-2, and 8-3 can be retrieved.

[0031] Furthermore, as shown in Fig. 3B, (C), (D) and (E), the wire 4-1 that has passed through the wire holes 41, 42 and 43 is folded back by the U-shaped pulley 221 of the guide mechanism 22b, passes through the grooved wire holes 53, 52 and 51 of the guide mechanisms 23'b, 23b and 21b and returns to the bending actuator 5-1a. In this case, the grooves of the grooved wire holes 51, 52 and 53 are for receiving the spherical stoppers 8-1, 8-2 and 8-3. The U-shaped pulley 221 is U-shaped so that the spherical stoppers 8-1, 8-2 and 8-3 can ride over it. The diameters D1', D2' and D3' of the grooved wire holes 53, 52 and 51 are D1' <D2’<D3’<D In this case, the relationship between the diameters D1, D2, and D3 of the spherical stoppers 8-1, 8-2, and 8-3 is as follows: D1' <D1<D2’<D2<D3’<D3<D Therefore, when wire 4-1 moves from bending actuator 5-1b toward bending actuator 5-1a, spherical stopper 8-3 stops at guide mechanism 23'b, spherical stopper 8-2 stops at guide mechanism 23b, and spherical stopper 8-1 stops at guide mechanism 21b.

[0032] FIG. 4 is a front view for explaining a driving method of the telescopic robot arm of FIG. 1, where (A) shows a bending preparation deployment process, (B) shows an inner tube bending process, (C) shows a first intermediate tube bending process, and (D) shows a second intermediate tube bending process.

[0033] First, referring to the bending preparation deployment process of (A) in FIG. 4, when the telescopic mechanism 2 is linearly moved in the radial direction R and deployed by a telescopic actuator (not shown) built into the base 1, since each of the cylinders 21, 23, 23', 22 of the telescopic mechanism 2 structurally forms a cantilever mechanism, the robot arm can hold a horizontal or inclined posture without consuming power. At this time, the wire 4-1 exists along the outer cylinder 21, the intermediate cylinders 23, 23', and the inner cylinder 22 of the telescopic mechanism 2 by the guide mechanisms 21b, 23b, 23'b. That is, since the diameters D1, D2, D3 of the spherical stoppers 8-1, 8-2, 8-3 of the wire 4-1 are smaller than the diameter D of the wire holes 41, 42, 43 of the guide mechanisms 21b, 23b, 23'b, the spherical stoppers 8-1, 8-2, 8-3 pass through the wire holes 41, 42, 43 of the guide mechanisms 21b, 23b, 23'b, 22b and are folded back by the U-shaped pulley 221 of the guide mechanism 22b. In this state, when the wire 4-1 is further fed out in synchronization with the linear extension by the two bending actuators 5-1a, 5-1b, since the diameter D1 of the spherical stopper 8-1 is between the diameters D1', D2' of the grooved wire holes 51, 52 of the guide mechanisms 21b, 23b, the spherical stopper 8-1 is positioned midway on the intermediate cylinder 23 between the guide mechanisms 21b, 23b. Since the diameter D2 of the spherical stopper 8-2 is between the diameters D2', D3' of the grooved wire holes 52, 53 of the guide mechanisms 23b, 23'b, the spherical stopper 8-2 is positioned midway on the intermediate cylinder 23' between the guide mechanisms 23b, 23'b. Since the diameter D3 of the spherical stopper 8-3 is larger than the diameter D3' of the guide mechanism 23'b, the spherical stopper 8-3 is positioned midway on the inner cylinder 22 between the guide mechanisms 23'b, 22b. At this time, the length L1' between the spherical stoppers 8-1, 8-2 is smaller than the length L1 of the intermediate cylinder 23 (L1'<L1), and the length L2' between the spherical stoppers 8-2, 8-3 is smaller than the length L2 of the intermediate cylinder 23' (L2'<L2). Further, the distance L3' between the spherical stopper 8-3 and the guide mechanism 22b is smaller than the length L3 of the inner cylinder 22 (L3'<L3). In this state, the bending actuator 5-1b is stopped, and one end of the wire 4-1 on the bending actuator 5-1b side is fixed at the position of the guide mechanism 22b.

[0034] Next, referring to the inner cylinder bending process in (B) of FIG. 4, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves further toward the bending actuator 5-1a. As a result, since the diameter D3 of the spherical stopper 8-3 is larger than the diameter D3' of the grooved wire hole 53 of the guide mechanism 23'b, the spherical stopper 8-3 abuts against the grooved wire hole 53 of the guide mechanism 23'b and stops. Therefore, a bending moment is generated in the inner cylinder 22 due to L3'<L3, and the inner cylinder 22 bends greatly upward. In this case, the spherical stopper 8-1 still exists between the guide mechanisms 21b and 23b, and the spherical stopper 8-2 still exists between the guide mechanisms 23b and 23'b.

[0035] Next, referring to the first intermediate cylinder bending process in (C) of FIG. 4, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves further toward the bending actuator 5-1a. As a result, since the diameter D2 of the spherical stopper 8-2 is larger than the diameter D2' of the grooved wire hole 52 of the guide mechanism 23b, the spherical stopper 8-2 abuts against the grooved wire hole 52 of the guide mechanism 23b and stops. Therefore, a bending moment is generated in the intermediate cylinder 23' due to L2'<L2, and the intermediate cylinder 23' bends greatly upward. In this case, the spherical stopper 8-1 still exists between the guide mechanisms 21b and 23b.

[0036] Finally, referring to the second intermediate cylinder bending process in (D) of FIG. 4, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves further toward the bending actuator 5-1a. As a result, since the diameter D1 of the spherical stopper 8-1 is larger than the diameter D1' of the grooved wire hole 51 of the guide mechanism 21b, the spherical stopper 8-1 abuts against the grooved wire hole 51 of the guide mechanism 21b. Therefore, a bending moment is generated in the intermediate cylinder 23 due to L1'<L1, and the intermediate cylinder 23 bends greatly upward. That is, the intermediate cylinder 23 bends greatly upward.

[0037] In this manner, the spherical stoppers 8-3, 8-2, 8-1 fit in the grooves of the grooved wire holes 53, 52, 51 of the guide mechanisms 23'b, 23b, 21b in this order, generating a bending moment that bends the inner cylinder 22 and the intermediate cylinders 23', 23 upward. When the spherical stoppers 8-3, 8-2, 8-1 come into contact with the guide mechanisms 21b, 23b, 23'b, the tension applied to the wire 4-1 by the bending actuator 5-1a is gradually reduced.This results in a large tension, i.e., a large bending moment, at the base side, where the second moment of area is large, and a small tension, i.e., a small bending moment, at the tip side, where the second moment of area is small.This increases the displacement of the entire arm and prevents buckling at the tip side.

[0038] Finally, the telescopic mechanism 2 is contracted by linearly moving it in the radial direction R using the expansion and contraction actuators, and the bending actuators 5-1a and 5-1b are wound up to store the wire 4-1, thereby terminating the drive. Since the diameter D of the wire holes 41, 42, and 43 of the guide mechanisms 21b, 23b, and 23'b is larger than the diameters D1, D2, and D3 of the spherical stoppers 8-3, 8-2, and 8-1, the wire 4-1 can be wound up and stored without slack.

[0039] Next, a first modified example of the telescopic robot arm of FIG. 1 will be described. Referring also to FIG. 5(A), in the first modified example, there is no telescopic actuator. One end of the wire 4-1 is fixed to the guide mechanism 22b' of the inner tube 22, and therefore the wire 4-1 is wound up only by the bending actuator 5-1a. As a result, there is no bending actuator 5-1b of FIG. 1 and no wire holes 41, 42, 43 of the guide mechanisms 21b, 23b, 23'b of FIG. 3, and no pulley is present in the guide mechanism 22b' of the inner tube 22. This simplifies the structure of the telescopic robot arm. However, the robot arm is not stored and is moved in the deployed state.

[0040] FIG. 5 is a front view for explaining the driving method of the above-described first modification example, where (A) shows the bending preparation deployment step, (B) shows the inner cylinder bending step, (C) shows the first intermediate cylinder bending step, and (D) shows the second intermediate cylinder bending step.

[0041] First, referring to the bending preparation deployment step of FIG. 5(A), the telescopic mechanism 2 is always in a stable deployed state. At this time, the wire 4-1 exists along the outer cylinder 21, intermediate cylinders 23, 23', and inner cylinder 22 of the telescopic mechanism 2 by the guide mechanisms 21b, 23b, 23'b, 22'b. In this state, since the diameter D1 of the spherical stopper 8-1 is between the diameters D1', D2' of the grooved wire holes 51, 52 of the guide mechanisms 21b, 23b, the spherical stopper 8-1 is located midway on the intermediate cylinder 23 between the guide mechanisms 21b, 23b. Since the diameter D2 of the spherical stopper 8-2 is between the diameters D2', D3' of the grooved wire holes 52, 53 of the guide mechanisms 23b, 23'b, the spherical stopper 8-2 is located midway on the intermediate cylinder 23' between the guide mechanisms 23b, 23'b. Since the diameter D3 of the spherical stopper 8-3 is larger than the diameter D3' of the guide mechanism 23'b, the spherical stopper 8-3 is located midway on the inner cylinder 22 between the guide mechanisms 23'b, 22'b. At this time, the length L1' between the spherical stoppers 8-1, 8-2 is smaller than the length L1 of the intermediate cylinder 23 (L1'<L1), and the length L2' between the spherical stoppers 8-2, 8-3 is smaller than the length L2 of the intermediate cylinder 23' (L2'<L2). Furthermore, the distance L3' between the spherical stopper 8-3 and the guide mechanism 22b is smaller than the length L3 of the inner cylinder 22 (L3'<L3).

[0042] Next, referring to the inner cylinder bending process of (B) in Fig. 5, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves toward the bending actuator 5-1a. As a result, since the diameter D3 of the spherical stopper 8-3 is larger than the diameter D3' of the grooved wire hole 53 of the guide mechanism 23'b, the spherical stopper 8-3 abuts against the grooved wire hole 53 of the guide mechanism 23'b and stops. Therefore, a bending moment is generated in the inner cylinder 22 due to L3' < L3, and the inner cylinder 22 bends greatly upward. Incidentally, in this case, the spherical stopper 8-1 still exists between the guide mechanisms 21b and 23b, and the spherical stopper 8-2 still exists between the guide mechanisms 23b and 23'b.

[0043] Next, referring to the first intermediate cylinder bending process of (C) in Fig. 5, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves further toward the bending actuator 5-1a. As a result, since the diameter D2 of the spherical stopper 8-2 is larger than the diameter D2' of the grooved wire hole 52 of the guide mechanism 23b, the spherical stopper 8-2 abuts against the grooved wire hole 52 of the guide mechanism 23b and stops. Therefore, a bending moment is generated in the intermediate cylinder 23' due to L2' < L2, and the intermediate cylinder 23' bends greatly upward. Incidentally, in this case, the spherical stopper 8-1 still exists between the guide mechanisms 21b and 23b.

[0044] Finally, referring to the second intermediate cylinder bending process of (D) in Fig. 5, when the wire 4-1 is wound up by the bending actuator 5-1a, the wire 4-1 moves further toward the bending actuator 5-1a. As a result, since the diameter D1 of the spherical stopper 8-1 is larger than the diameter D1' of the grooved wire hole 51 of the guide mechanism 21b, the spherical stopper 8-1 abuts against the grooved wire hole 51 of the guide mechanism 21b. Therefore, a bending moment is generated in the intermediate cylinder 23 due to L1' < L1, and the intermediate cylinder 23 bends greatly upward. That is, the intermediate cylinder 23 bends greatly upward.

[0045] In this way, the spherical stoppers 8-3, 8-2, 8-1 fit in the grooves of the grooved wire holes 53, 52, 51 of the guide mechanisms 23'b, 23b, 21b in this order, generating a bending moment and bending the inner tube 22 and the intermediate tubes 23', 23 upward. When the spherical stoppers 8-3, 8-2, 8-1 and the guide mechanisms 21b, 23b, 23'b collide with each other, the tension applied to the wire 4-1 by the bending actuator 5-1a is reduced in stages. By creating a large tension, i.e., a large bending moment, at the base side where the second moment of area is large and a small tension, i.e., a small bending moment, at the tip side where the second moment of area is small, the displacement of the entire arm can be increased and buckling at the tip side can be prevented.

[0046] Finally, the winding of the bending actuator 5-1a is loosened to terminate the drive.

[0047] FIG. 6 shows a second modified example of the telescopic robot arm of FIG. 1, where (A) is a front view of the deployed state, and (B) is a perspective view of the guide mechanism of (A).

[0048] In Fig. 6, wires 4-2 and 4-3 and bending actuators 5-2a, 5-2b, 5-3a, and 5-3b are added to the telescopic robot arm of Fig. 1, and three-way guide mechanisms 121b, 123b, 123'b, and 122b are provided instead of the one-way guide mechanisms 21b, 23b, 23'b, and 22b. In this case, spherical stoppers 8-1-2, 8-2-2, and 8-3-2 are provided on the wire 4-2, and spherical stoppers 8-1-3, 8-2-3, and 8-3-3 are provided on the wire 4-3. This allows the telescopic robot arm of Fig. 6 to bend in two dimensions, enabling wide-range observation.

[0049] In the above-described embodiment, the wire holes 41, 42, 43 can also be used for the outer tube 21, the intermediate tube 23, 23', and the inner tube 22 which pass through the tube holes 31, 32, 33, 34, thereby making it possible to reduce the size of the guide mechanisms 21b, 23b, 23'b, 22b.

[0050] Moreover, the above-mentioned spherical stoppers 8-1, 8-2, and 8-3 may be spindle-shaped instead of spherical.

[0051] Furthermore, in the above-described embodiment, the bending moment of each cylinder can be increased by increasing the radial length of each cylinder of guide mechanisms 21b, 23b, and 23'b.

[0052] Furthermore, in the above-mentioned embodiment, the outer cylinder 21, the intermediate cylinders 23, 23', and the inner cylinder 22 are made of the same material, but they may be made of materials whose rigidity decreases from the tip side to the base side. In other words, the geometrical moment of inertia of the outer cylinder 21 and the intermediate cylinders 23, 23' on the base 1 side is made equal to or smaller than the geometrical moment of inertia of the inner cylinder 22. This allows the overall displacement of the robot arm to be increased.

[0053] Furthermore, the present invention can be applied to any modifications within the obvious scope of the above-described embodiments. [Industrial Applicability]

[0054] The present invention can be used as a robot arm for working at height other than as a camera driving device for observing nuclear fuel in a nuclear power plant. [Explanation of symbols]

[0055] 1: Base 2: Telescopic mechanism 21: Outer cylinder 22: Inner cylinder 23, 23', 23": Intermediate tube 21a, 22a, 23b, 23'b, 23"b; 21b, 22b, 22b', 23b, 23'b, 121b, 122b, 123b, 123'b: Guide mechanism 3: Camera 4-1, 4-2, 4-3: Wire 5-1a, 5-1b, 5-2a, 5-2b, 5-3a, 5-3b, 5-1, 5-2, 5-3: Bending actuators 6: Support rod 7: Mobile stand 31, 32, 33, 34: Cylinder hole 41, 42, 43: Wire holes 51, 52, 53: Slotted wire holes

Claims

1. a base, an outer cylinder fixed to the base, an inner cylinder inserted into the outer cylinder, at least one intermediate cylinder inserted between the outer cylinder and the inner cylinder, a first guide mechanism provided at the tip of the outer cylinder and the tip of the intermediate cylinder, having first and second holes, a second guide mechanism provided at the tip of the inner cylinder, a telescopic actuator provided in the base for interlocking and deploying the intermediate cylinder and the inner cylinder with respect to the outer cylinder, first and second bending actuators provided in the base for bending the intermediate cylinder and the inner cylinder with respect to the outer cylinder, a wire that passes through the first hole of the first guide mechanism of the outer cylinder and the first hole of the first guide mechanism of the intermediate cylinder from the first bending actuator, is folded back by the second guide mechanism of the inner cylinder, passes through the second hole of the first guide mechanism of the intermediate cylinder and the second hole of the first guide mechanism of the outer cylinder, and is wound around the second bending actuator, with a plurality of stoppers fixed thereto comprising, the diameters of the plurality of stoppers increase sequentially from the first bending actuator toward the second bending actuator, the diameter of the first hole of the first guide mechanism of the outer cylinder and the diameter of the first hole of the first guide mechanism of the intermediate cylinder are smaller than the maximum diameter of the stopper, the diameter of the second hole of the first guide mechanism of the outer cylinder and the diameter of the second hole of the first guide mechanism of the intermediate cylinder are larger than the maximum diameter of the stopper, the first hole of the first guide mechanism of the outer cylinder does not allow the stopper to pass through, the first hole of the first guide mechanism of the intermediate cylinder allows at least one of the plurality of stoppers to pass through, and does not allow another one of the plurality of stoppers on the second bending actuator side of the at least one stopper to pass through, a telescopic robotic arm in which the length of the intermediate cylinder is greater than the distance between the stopper that has passed through the first hole of the first guide mechanism of the intermediate cylinder and the stopper adjacent to the stopper that cannot pass through the first hole.

2. The telescopic robotic arm according to claim 1, wherein the second guide mechanism provided at the tip of the inner cylinder comprises a U-shaped pulley.

3. The telescopic robotic arm according to claim 1, wherein the first hole is a grooved hole for receiving the stopper.

4. a base, an outer cylinder fixed to the base, an inner cylinder inserted into the outer cylinder, At least one intermediate cylinder inserted between the outer cylinder and the inner cylinder; A first guide mechanism provided at the tip of the outer cylinder and the tip of the intermediate cylinder and having holes; A second guide mechanism provided at the tip of the inner cylinder; A bending actuator provided in the base for bending the intermediate cylinder and the inner cylinder with respect to the outer cylinder; A wire fixed to the second guide mechanism of the inner cylinder, passing through the holes of the first guide mechanism of the intermediate cylinder and the holes of the first guide mechanism of the outer cylinder, wound around the bending actuator, and having a plurality of stoppers fixed thereto; Comprising; The diameters of the plurality of stoppers increase sequentially from the bending actuator toward the second guide mechanism of the inner cylinder; The diameters of the holes of the first guide mechanism of the outer cylinder and the diameters of the holes of the first guide mechanism of the intermediate cylinder increase sequentially from the bending actuator toward the second guide mechanism of the inner cylinder; The holes of the first guide mechanism of the outer cylinder do not allow the stoppers to pass through; The holes of the first guide mechanism of the intermediate cylinder allow at least one of the plurality of stoppers to pass through, and do not allow the other one of the plurality of stoppers on the inner cylinder side of the at least one stopper to pass through; The length of the intermediate cylinder is greater than the distance between the stopper that has passed through the hole of the first guide mechanism of the intermediate cylinder and the stopper that cannot pass through the hole adjacent to the stopper; A telescopic type robot arm in which the length of the inner cylinder is greater than the distance between the stopper inside the inner cylinder and the second guide mechanism of the inner cylinder.

5. The telescopic type robot arm according to claim 4, wherein the hole is a grooved hole for receiving the stopper.

6. The telescopic type robot arm according to claim 1 or 4, wherein the stopper is a spherical stopper.

7. The telescopic type robot arm according to claim 6, wherein the spherical stopper has a hole formed therein in advance, and the wire is wound around the hole of the spherical stopper once or a plurality of times.

8. The telescopic type robot arm according to claim 6, wherein the spherical stopper is formed by winding the wire around a cylinder in one of two split spherical stoppers in advance and then bonding the two split spherical stoppers.

9. The telescopic robotic arm according to claim 6, wherein a hole is formed in the spherical stopper in advance, the wire is passed through the hole of the spherical stopper, and ball knots of the wire are formed before and after the spherical stopper.

10. The telescopic robotic arm according to claim 6, wherein a hole is formed in the spherical stopper in advance, the wire is passed through the hole of the spherical stopper, and the wire is caulked from the spherical stopper.

11. The telescopic robotic arm according to claim 6, wherein the spherical stopper loosens the wire, inserts the spherical stopper into the space inside the wire, and the spherical stopper is housed in the wire by pulling the wire.

12. The telescopic robotic arm according to claim 11, wherein a ball is further fitted into the wire housing the spherical stopper.

13. The telescopic robotic arm according to claim 1 or 4, wherein the wire is made of a lightweight, high-strength, low-friction coefficient material wire.

14. The telescopic robotic arm according to claim 13, wherein the lightweight, high-strength, low-friction coefficient material wire is made of high-strength chemical fiber.

15. The telescopic robotic arm according to claim 1 or 4, wherein the rigidity of each material of the outer cylinder, the intermediate cylinder, and the inner cylinder is smaller toward the base side.

16. A driving method of the telescopic robotic arm according to claim 1, comprising: A bending preparation deployment step of deploying the intermediate cylinder and the inner cylinder in conjunction with the outer cylinder by the telescopic actuator, feeding out the wire by the first and second bending actuators to fully deploy it, and then winding up the second bending actuator to stop the stopper on the first bending actuator side of the plurality of stoppers midway on the inner cylinder; An inner cylinder / intermediate cylinder bending step of bending the inner cylinder and the intermediate cylinder by winding up the wire by the first bending actuator with the second bending actuator stopped after the bending preparation deployment step. A driving method of a telescopic robotic arm comprising the above steps.

17. A driving method of the telescopic robotic arm according to claim 4, comprising: A bending preparation and deployment step of feeding out the wire by the bending actuator, winding it up on the bending actuator, and stopping the stopper on the second guide mechanism side of the inner cylinder of the plurality of stoppers midway on the inner cylinder; An inner cylinder / intermediate cylinder bending step of bending the inner cylinder and the intermediate cylinder by winding up the wire with the bending actuator after the bending preparation and deployment step; A driving method for a telescopic type robot arm comprising the above steps.

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