robot

Abstract

This robot provides energy consumption that can be kept low compared to conventional technologies. [Solution] A robot for performing work underwater, comprising a robot body, a propulsion unit, an arm unit 4, and a control unit. The arm unit 4 has one or more links 7 (first link 11 and second link 12) and a work unit 8 provided at the tip of the link 7. The link 7 has a link body 81, a connecting part 82 that connects the link body 81 so as to be rotatable around a pivot axis OX, and an actuator 83 that rotates the link body 81. The connecting part 82 is provided in the longitudinal direction of the link 7 at a position equivalent to the center of gravity positions G1 and G2 of each link body 81.

Description

Technical Field

[0001] The present invention relates to a robot.

Background Art

[0002] Conventionally, various techniques for controlling the posture of underwater robots that perform work underwater have been proposed.

[0003] For example, Patent Document 1 discloses a configuration of an underwater robot having a frame, a propulsion unit, a weight, a buoyancy material, and a drive mechanism. The weight moves along a first axis direction (front-rear direction), and the buoyancy material is movable along a second axis direction (up-down direction) orthogonal to the first axis. According to the technique described in Patent Document 1, it is stated that the position and posture of the robot can be controlled to an arbitrary state by moving the weight and the buoyancy material in synchronization with each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, such an underwater robot may be provided with a working unit (such as a mechanical arm) for performing work underwater. For example, when an extendable working arm is provided, as the working arm is extended far from the robot main body, the center of gravity of the entire robot moves toward the working arm side, and the posture of the robot changes. Therefore, in order to maintain the posture of the robot, it is necessary to perform posture control on the robot main body side in accordance with the extension and bending of the working arm. However, in the conventional technology that performs posture control each time the working arm extends or bends, it is necessary to execute posture control constantly, which may lead to an increase in energy consumption.

[0006] Therefore, the present invention aims to provide a robot that can reduce energy consumption compared to conventional technology. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following embodiments. (1) A robot according to one aspect of the present invention (for example, robot 1 in the embodiment) comprises a robot body (for example, robot body 2 in the embodiment), a propulsion unit that drives the robot body (for example, thruster 3 in the embodiment), an arm unit (for example, arm unit 4 in the embodiment) connected to the robot body and having one or more links (for example, link 7 in the embodiment) and a working part (for example, working part 8 in the embodiment) provided at the tip of the link, an actuator (for example, actuator 83 in the embodiment) that drives the arm unit and a control unit (for example, control unit 5 in the embodiment) that controls the propulsion unit, wherein the link is a link body The link comprises (for example, a link body 81 in the embodiment), a connecting portion (for example, a connecting portion 82 in the embodiment) that connects the link body to the robot body so as to be rotatable around a pivot axis (for example, a pivot axis OX in the embodiment), and an actuator attached to the link body that rotates the link body around the pivot axis, wherein the connecting portion is provided at a position in the longitudinal direction of the link that is equivalent to the center of gravity position (for example, center of gravity positions G1 and G2 in the embodiment) of the link, including the link body, the actuator, and the parts to be attached to the tip of the link body (for example, the first part to be attached 45 and the second part to be attached 55 in the embodiment).

[0008] (2) In the robot described in (1) above, the link may have a first link (for example, a first link 11 in the embodiment) and a second link (for example, a second link 12 in the embodiment), and the first link may have a first link body (for example, a first link body 41 in the embodiment), a first connecting part (for example, a first connecting part 42 in the embodiment) that connects the robot body and the first link body so as to be rotatable around a first pivot axis (for example, a first pivot axis O1 in the embodiment), and a first actuator (for example, a first actuator 43 in the embodiment) that rotates the first link around the first pivot axis, and the second link may have a second link body (for example, a second link body 51 in the embodiment) that is connected to the tip of the first link body, and a second connecting part (for example, The first link may also have a second connecting portion 52 in the embodiment and a second actuator (for example, a second actuator 53 in the embodiment) that rotates the second link around the second pivot axis, and the working portion may be provided at the tip of the second link body (for example, the tip 12a in the embodiment), the first connecting portion may be provided at a position in the longitudinal direction of the first link that is equivalent to the center of gravity position of the first link (for example, the center of gravity position G1 in the embodiment) including the first link body, the first actuator and a first mountable part attached to the tip of the first link body (for example, the first mountable part 45 in the embodiment), and the second connecting portion may be provided at a position in the longitudinal direction of the second link that is equivalent to the center of gravity position of the second link (for example, the center of gravity position G2 in the embodiment) including the second link body, the second actuator and a working portion attached to the tip of the second link body.

[0009] (3) In the robot described in (1) above, the actuator may be provided on the base end (for example, base end 11b, 12b in the embodiment) side of the link in the longitudinal direction, which is on the side opposite to the tip end to which the component to be attached is attached, rather than the connecting portion.

[0010] (4) In the robot described in (1) above, the link may further have a buoyancy body (for example, the buoyancy body 261 in the embodiment) provided on the tip side of the link rather than the connecting portion in the longitudinal direction of the link, and the robot may perform work underwater.

[0011] (5) In the robot described in (1) above, the link may further have a counterweight (for example, the counterweight 262 in the embodiment) provided on the base end side of the link, which is located on the side opposite to the tip end to which the component to be attached is attached, rather than the connecting portion, in the longitudinal direction of the link.

[0012] (6) The robot described in (1) above may further include a transmission mechanism (for example, a first transmission mechanism 46 and a second transmission mechanism in the embodiment) which includes a first gear (for example, a first gear 65 in the embodiment) connected to the output shaft of the actuator, and a second gear (for example, a second gear 66 in the embodiment) connected to the first gear and transmitting the rotational force from the first gear to the connecting part.

[0013] (7) In the robot described in (6) above, at least one of the first gear and the second gear may be a bevel gear.

[0014] (8) The robot described in (1) above may further include a transmission mechanism comprising a drive pulley connected to the output shaft of the actuator (for example, a drive pulley 471 in the embodiment), a passive pulley connected to the connecting portion (for example, a passive pulley 472 in the embodiment), and a belt (for example, a belt 475 in the embodiment) that transmits output from the drive pulley to the passive pulley.

[0015] (9) In the robot described in any one of the above paragraphs (1) to (8), the control unit may have a posture control unit that performs posture control by changing at least one of the center of gravity and center of buoyancy of the robot by moving a buoyancy member, the work unit may be a hand having a plurality of fingers (for example, 13 in the embodiment), and the control unit may determine whether the hand is grasping an object and switch the posture control on and off based on the determination result. [Effects of the Invention]

[0016] According to the embodiment of (1) above, the arm portion comprises a link body, a connecting portion, and an actuator. By rotating the link body around the connecting portion, the arm portion (or the working portion provided at the tip of the arm portion) can be extended or bent relative to the robot body. The connecting portion is provided at a position equivalent to the center of gravity of the link in the longitudinal direction of the link. This makes it possible to reduce the amount of change in the center of gravity of the entire arm portion even when the arm portion is extended or bent due to the rotation of the link body. In particular, when the position of the connecting portion and the center of gravity of the link coincide, the center of gravity of the entire arm portion remains unchanged regardless of whether the arm portion is extended or bent. Therefore, compared to conventional technology in which attitude control is performed each time the arm portion is extended or bent, the energy consumption related to attitude control can be kept to a minimum. Furthermore, even when the connecting portion is positioned near the center of gravity of the link (i.e., the position of the connecting portion and the center of gravity of the link do not perfectly coincide), energy consumption can be kept lower compared to the conventional technology. Generally, when an arm is constructed using a link mechanism, the connecting portion (the pivot axis of the link) is often provided near the end of the link in order to maximize the range of motion of the arm. In other words, in the conventional technology, which does not consider the center of gravity, the connecting portion is often provided at a position far from the center of gravity of the link. In contrast, according to the embodiment of the present invention, by providing the connecting portion near the center of gravity of the link, the change in posture associated with the extension or flexion of the arm can be reduced compared to the conventional technology in which the connecting portion is provided at a position far from the center of gravity of the link. Therefore, the energy consumption related to posture control can be reduced. Therefore, we can provide a robot that can keep energy consumption low compared to conventional technology.

[0017] According to the embodiment of (2) above, since there are two links, a first link and a second link, a large range of motion can be secured by rotating each link around its pivot axis, allowing for extension or flexion of the arm. Furthermore, since the connecting parts of each link are provided at positions equivalent to the center of gravity of each link, even when multiple links are used, the change in the center of gravity of the entire arm due to extension or flexion can be kept small. Thus, the usability of the robot can be improved while reducing energy consumption.

[0018] According to the embodiment of (3) above, since the heavy actuator is provided on the base end side of the link body, it becomes easier to balance the weight with the attached parts (other links, working parts, etc.) provided on the tip side of the link. In addition, by providing the actuator on the base end side, the center of gravity of the link can be positioned on the base end side in the longitudinal direction of the link body. As a result, the connecting part can be provided on the base end side, and a larger range of motion of the arm due to the rotation of the link can be secured compared to the case where the connecting part is provided on the tip side. Therefore, the versatility of the robot can be improved while suppressing energy consumption related to attitude control.

[0019] According to the aspect (4) described above, the buoyancy body is provided on the distal end side of the link main body. Thereby, particularly when the robot performs work underwater, the buoyancy on the distal end side of the link can be increased, making it easier to adjust the weight balance of the entire link. In addition, since the distal end portion of the link is made lighter, the center of gravity of the link can be positioned relatively closer to the base end portion in the longitudinal direction of the link main body. Thereby, the connecting portion can be disposed on the base end side, and a large movable range of the arm portion due to rotation of the link can be secured. Therefore, the versatility of the robot can be improved. Further, a configuration suitable particularly for a robot that performs work underwater can be achieved.

[0020] According to the aspect (5) described above, the counterweight is provided on the base end side of the link main body. Thereby, the weight on the base end side of the link can be easily increased, making it easier to adjust the weight balance of the entire link. In addition, since the center of gravity of the link can be positioned closer to the base end portion in the longitudinal direction of the link main body, a large movable range of the arm portion due to rotation of the link can be secured. Therefore, the versatility of the robot can be improved.

[0021] According to the aspect (6) described above, the output from the actuator can be transmitted to the connecting portion via the plurality of gears. Therefore, the actuator can be disposed at an arbitrary position. This makes it easier to adjust the position of the center of gravity of the link, and the versatility of the robot can be improved.

[0022] According to the aspect (7) described above, at least a part of the plurality of gears is a bevel gear. Thereby, a configuration suitable for the case where the output shaft of the actuator intersects the rotation shaft of the link can be achieved. Therefore, the versatility of the robot can be improved.

[0023] According to the aspect (8) described above, the output of the actuator and the rotation shaft (connecting portion) of the link can be connected by the belt. Therefore, the versatility of the robot can be improved.

[0024] According to the aspect (9) described above, the control unit provided in the robot main body switches between enabling and disabling the attitude control based on the result of determining whether the working unit (hand) is gripping an object. For example, when the working unit is not gripping an object, the attitude control is disabled. Thereby, unnecessary energy consumption related to the attitude control can be suppressed. Further, when it is detected that the working unit has gripped an object, the attitude control is enabled. Thereby, appropriate attitude control can be executed in response to a change in the center of gravity of the arm unit. Therefore, the attitude of the robot can be maintained while minimizing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [Figure 1] A perspective view showing the configuration of the robot according to the first embodiment. [Figure 2] A front view showing a state when the arm unit is extended. [Figure 3] A front view showing a state when the arm unit is bent. [Figure 4] A front view showing the configuration of the transmission mechanism according to the first embodiment. [Figure 5] A side view showing the configuration of the transmission mechanism according to the first embodiment. [Figure 6] A control flow diagram in the control unit. [Figure 7] A front view showing the configuration of the transmission mechanism according to the second embodiment. [Figure 8] A side view showing the configuration of the transmission mechanism according to the second embodiment. [Figure 9] A front view showing the configuration of the transmission mechanism according to the third embodiment. [Figure 10] A side view showing the configuration of the transmission mechanism according to the third embodiment. [Figure 11] A side view showing the configuration of a transmission mechanism according to a modification of the third embodiment. [Figure 12] A front view showing the configuration of the transmission mechanism according to the fourth embodiment. [Figure 13] A side view showing the configuration of the transmission mechanism according to the fourth embodiment. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0026] Embodiments of the present invention will be described below with reference to the drawings. In the following explanation, as an example of robot 1, we will describe a remotely operated vehicle (ROV) that operates underwater (an example being underwater) via remote control such as wired communication. The robot 1 of the embodiment is, for example, an unmanned mobile vehicle on and underwater, such as a UUV (Unmanned Undersea Vehicle) or USV (Unmanned Surface Vehicle). For example, an unmanned underwater vehicle, such as a UUV, includes remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs). For example, a remotely operated ROV includes so-called underwater drones.

[0027] (First Embodiment) Figure 1 is a perspective view showing the configuration of robot 1 according to the first embodiment. In the following explanation, we will use the X, Y, and Z axes, which are mutually orthogonal in three-dimensional space, as a reference. For example, as shown in Figure 1, the X-axis direction is parallel to the front-to-back direction of robot 1, the Y-axis direction is parallel to the left-to-right direction (width direction) of robot 1, and the Z-axis direction is parallel to the up-to-down direction of robot 1. For example, the positive direction of the X-axis is the front direction of robot 1, the positive direction of the Y-axis is the left direction of robot 1, and the positive direction of the Z-axis is the up direction of robot 1.

[0028] As shown in Figure 1, the robot 1 comprises a robot body 2, a plurality of thrusters 3 (propulsion unit according to the claim), an arm unit 4, and a control unit 5. The robot body 2 comprises a lower body 20 and an upper body 21 that are connected to each other.

[0029] The lower part of the main body 20 has a plurality of support members 24 and plate members 23 that form the frame 22, which is the skeleton of the robot 1. The outer shape of each of the plurality of support members 24 is formed as a column extending in the vertical direction. The plurality of support members 24 are fixed to, for example, the corners of the plate members 23 and are also connected to the upper part of the main body 21, which will be described later. The plate members 23 are formed as, for example, rectangular plates along the XY plane. The plate members 23 support various devices mounted on the lower part of the main body 20.

[0030] The lower part of the main body 20 includes, for example, a pair of arm sections 4 (details to be described later), a plurality of thrusters 3, a camera system 25, a sensor 26, a power unit 27, one forward control unit 28, and two rearward control units 29.

[0031] Each base end of a pair of arm sections 4 is fixed to the left and right corners of the front part of the plate member 23. Each arm section 4 is, for example, a manipulator and includes a connecting section (joint) driven by an actuator (see Figure 2) and a plurality of links 7 connected by the connecting section. Each arm section 4 includes, for example, a working section 8 provided at its tip for performing various tasks such as grasping and moving objects. Each arm section 4 is equipped with a power device 27 at its base end that outputs power for operation. Each arm section 4 is, for example, positioned inside the left and right ends of the plate member 23 when stopped, and its tip protrudes outward (forward, etc.) from the robot 1 when in operation.

[0032] The multiple thrusters 3 include two forward thrusters 32 located at the front of the plate member 23, two rear thrusters 33 located at the rear of the plate member 23, and two central thrusters 31 located in the center of the plate member 23 in the front-rear direction. Each thruster 3 (forward thrusters 32, rear thrusters 33, and central thrusters 31) is provided in pairs, arranged side by side. The forward thrusters 32 and aft thrusters 33 are so-called azimuth thrusters. Each forward thruster 32 and each aft thruster 33 comprises, for example, a support that rotates around a vertical axis along the vertical direction, and a propeller that is supported by the support and rotates around a horizontal axis perpendicular to the vertical axis. The forward thrusters 32 and aft thrusters 33 generate thrust in a direction perpendicular to the vertical direction. Each central thruster 31 comprises, for example, a propeller that rotates around a rotation axis that is inclined at a sharp angle with respect to the vertical direction. Each central thruster 31 generates thrust in at least one direction, including the vertical direction.

[0033] The camera system 25 is positioned at the front and center of the plate member 23 in the left-right direction. The camera system 25 includes, for example, a camera that captures images of the area outside the front of the robot 1, and multiple lights that illuminate the area outside the front of the robot 1. The sensor 26 is positioned, for example, at the front of the plate member 23 and below the camera system 25. The sensor 26 is, for example, a Doppler Velocity Log (DVL) that detects relative velocity based on the emission of sound waves and the detection of reflected and scattered waves.

[0034] One front-side control unit 28 is positioned, for example, at the front of the plate member 23, behind the camera system 25. The two rear control units 29 each include, for example, a box-shaped housing that seals the interior, and a power supply and electronic control unit (not shown) located inside the housing. Each rear control unit 29 controls the operation of each arm section 4, each thruster 3, camera system 25, sensor 26, and the drive unit 19 provided on the upper part 21 of the main body, which will be described later.

[0035] The upper part 21 of the main body includes a cover member 17, a movable member 18, and a drive unit 19. The cover member 17 has an external shape, for example, that of a rectangular box, and has a surface with multiple through holes that allow passage between the inside and outside. The cover member 17 is connected to the frame 22 of the lower part of the main body 20 via a skeletal member (not shown) provided inside the cover member 17. This skeletal member (not shown) is fixed to the support member 24 of the lower part of the main body 20 and supports the cover member 17, the movable member 18, and the drive unit 19.

[0036] The movable member 18 is provided inside the cover member 17 so as to be movable in the X-axis and Y-axis directions relative to a skeletal member (not shown). The movable member 18 includes, for example, a buoyancy member (not shown) that generates buoyancy. The movable member 18 is moved inside the cover member 17 by the drive unit 19 to change at least one of the center of buoyancy and the center of gravity of the robot 1 as a whole. The movable member 18 is moved to maintain or change the posture of the robot 1, for example, when the robot 1 is moving or when each arm 4 is operating.

[0037] The drive unit 19 is provided in pairs, for example, at the left and right corners of the cover member 17, and each has a power source. The power source is, for example, an electric motor. Each power source generates power to move the movable member 18. Inside the cover member 17, each power source is connected to a moving mechanism (not shown). The moving mechanism is, for example, a mechanism that moves the moving member 18 by two-dimensional translational motion in a two-dimensional Cartesian coordinate system of the X and Y axes. The moving mechanism may be a so-called H-BOT or H-type gantry robot, etc.

[0038] Figure 2 is a front view showing the arm 4 in its extended state. Figure 3 is a front view showing the arm 4 in its bent state. Figure 2 shows the arm 4 in its most extended state. Figure 3 shows the state in which at least a part of it is bent compared to the state in Figure 2. Since the pair of arm sections 4 have a symmetrical configuration, the following explanation will describe one arm section 4 (for example, the left arm section 4) and omit the explanation of the other arm section 4. Also, in Figures 2 and 3, the center of gravity position G0 of the robot body 2 and the center of gravity positions G1 and G2 of each link 7 in the arm are shown for illustrative purposes.

[0039] The arm portion 4 has one or more links 7 (two in this embodiment) and a working portion 8 provided at the tip of the link 7. In the embodiment described below, an example is described in which the arm section 4 has two links 7 (first link 11 and second link 12) and a working section 8. Each link 11, 12 comprises a link body (first link body 41, second link body 51), a connecting section (first connecting section 42, second connecting section 52) provided coaxially with the pivot axis (first pivot axis O1, second pivot axis O2) of the link body, an actuator (first actuator 43, second actuator 53) that rotates the link body around the connecting section (around the pivot axis), a mounting section (first mounting section 44, second mounting section 54) for attaching a component to be attached (first component to be attached 45, second component to be attached 55) to the link body, and a transmission mechanism (first transmission mechanism 46, second transmission mechanism (not shown)). Note that when the first link body 41 and the second link body 51 are not distinguished from each other, they may be collectively referred to as the link body 81. Similarly, when the first connecting portion 42 and the second connecting portion 52 are not distinguished from each other, they may be collectively referred to as the connecting portion 82. When the first actuator 43 and the second actuator 53 are not distinguished from each other, they may be collectively referred to as the actuator 83. When the first pivot shaft O1 and the second pivot shaft O2 are not distinguished from each other, they may be collectively referred to as the pivot shaft OX.

[0040] As shown in Figures 2 and 3, the first link 11 is mounted to the robot body 2 so as to be rotatable around a first pivot axis O1 along the Z-axis direction. The first link 11 includes a first link body 41, a first connecting portion 42, a first actuator 43, a first mounting portion 44, and a first transmission mechanism 46 (see Figure 4). The first link body 41 is oriented in a plate-like shape along the XY plane, with one direction intersecting the Z-axis as its long axis. In this embodiment, the outer shape of the first link body 41 is formed such that the width dimension perpendicular to the longitudinal direction gradually decreases from one end to the other in the longitudinal direction. In the following description, one end of the first link body 41 in the longitudinal direction (the one with the larger width dimension) may be referred to as the base end 11b, and the opposite end (the one with the smaller width dimension) may be referred to as the tip end 11a.

[0041] The first connecting portion 42 is located approximately in the center of the first link body 41 in the longitudinal direction. The first connecting portion 42 connects the robot body 2 and the first link body 41 so that they can rotate around the first pivot axis O1. In other words, the central axis of the first connecting portion 42 coincides with the first pivot axis O1. The position where the first connecting portion 42 is located will be described in detail later.

[0042] The first actuator 43 is located on the base end 11b side of the first link body 41, relative to the first connecting portion 42. The first actuator 43 is built into the first link body 41. The first actuator 43, for example, has a motor inside and outputs rotational force from the motor to rotate the first link 11 around the first pivot axis O1 relative to the robot body 2.

[0043] The first mounting portion 44 is located on the tip portion 11a side of the first link body 41, relative to the first connecting portion 42. The first component to be mounted 45 is attached to the first mounting portion 44. The first component to be mounted 45 is a general term for the components located downstream of the first link 11 when the robot body 2 is considered upstream, in a state where the work unit 8 is not gripping an object. In this embodiment, the first component to be mounted 45 includes the second link 12 and the work unit 8.

[0044] Figure 4 is a front view showing the configuration of the transmission mechanism (first transmission mechanism 46) according to the first embodiment. Figure 5 is a side view showing the configuration of the transmission mechanism (first transmission mechanism 46) according to the first embodiment. Note that in Figures 4 and 5, some parts other than the first transmission mechanism 46 are not shown. Also, the dashed lines in the figures indicate reference lines extending in the X, Y, and Z axes, respectively, centered on the centroid position G1 of the first link 11. As shown in Figures 4 and 5, the first transmission mechanism 46 has first to fourth gears 65, 66, 67, and 68. The first gear 65 is connected to the output shaft of the first actuator 43 and rotates integrally with the output shaft of the first actuator 43. As shown in Figure 5, the output shaft of the first actuator 43 protrudes from the first link body 41, for example, in the +Z axis direction. The second gear 66 is located at the same position as the first gear 65 in the Z axis direction and meshes with the first gear 65. The third gear 67 is connected to the second gear 66 via a gear shaft extending along the Z axis direction and rotates integrally with the second gear 66. The third gear 67 is located in the -Z axis direction relative to the first link body 41. Furthermore, a fourth gear 68 is provided so as to be integrally rotatable on the portion of the first connecting portion 42 that protrudes from the first link body 41 in the -Z axis direction. The fourth gear 68 meshes with the third gear 67.

[0045] In this way, the rotational force of the first actuator 43 is transmitted to the first connecting part 42 by the multiple gears of the first transmission mechanism 46, causing the first link 11 to rotate around the first pivot axis O1. Furthermore, the first gear 65 and the second gear 66 are provided in the +Z-axis direction relative to the first link body 41, and the third gear 67 and the fourth gear 68 are provided in the -Z-axis direction relative to the first link body 41. By distributing the multiple gears in the first transmission mechanism 46 on both sides in the Z-axis direction in this way, the center of gravity G1 of the first link 11 can be set in the center of the first link body 41 in the thickness direction.

[0046] As shown in Figures 2 and 3, the second link 12 is rotatably mounted to the first mounting portion 44 of the first link 11 around a second pivot axis O2 along the Z-axis direction. The second link 12 includes a second link body 51, a second connecting portion 52, a second actuator 53, a second mounting portion 54, and a second transmission mechanism (not shown). The second link body 51 is oriented in a plate-like shape along the XY plane, with one direction intersecting the Z-axis as its long axis. In this embodiment, the external shape of the second link body 51 is formed similarly to that of the first link body 41, such that the width dimension perpendicular to the longitudinal direction gradually decreases from one end to the other in the longitudinal direction. In the following description, one end of the second link body 51 in the longitudinal direction (the one with the larger width dimension) may be referred to as the base end 12b, and the opposite end (the one with the smaller width dimension) may be referred to as the tip end 12a.

[0047] The second connecting portion 52 is located approximately in the center of the second link body 51 in the longitudinal direction. The second connecting portion 52 connects the first mounting portion 44 of the first link body 41 to the second link body 51 so that it can rotate around the second pivot axis O2. In other words, the central axis of the second connecting portion 52 coincides with the second pivot axis O2. The position where the second connecting portion 52 is located will be described in detail later.

[0048] The second actuator 53 is located on the base end 12b side of the second link body 51, relative to the second connecting portion 52. The second actuator 53 is built into the second link body 51. The second actuator 53, for example, has a motor inside and outputs rotational force from the motor to rotate the second link 12 around the second pivot axis O2 relative to the first link 11.

[0049] The second mounting portion 54 is located on the tip portion 12a side of the second link body 51, relative to the second connecting portion 52. The second mounting component 55 is attached to the second mounting portion 54. The second mounting component 55 is a general term for components located further downstream than the second link 12 when the working portion 8 is not gripping an object. In this embodiment, the second mounting component 55 includes the working portion 8.

[0050] The second transmission mechanism (not shown) has multiple gears and transmits the output (rotational force) of the second actuator 53 to the second connecting part 52. In this embodiment, the configuration of the second transmission mechanism is the same as that of the first transmission mechanism 46 described above, so its explanation is omitted.

[0051] As shown in Figure 3, a work section 8 is provided on the second mounting section 54 (the tip 12a of the second link body 51) via a work section connecting section 14. The work section 8 is rotatably mounted to the second link body 51 around a pivot axis along the Z-axis direction. In this embodiment, the work section 8 is a hand having a plurality of fingers 13. Therefore, the work section 8 is capable of gripping objects. The work section 8 incorporates a motor 16 for driving the fingers 13. The work section 8 also has a work section actuator 15 for rotating the work section connecting section 14 relative to the second link 12. The work section actuator 15 and the motor 16 for driving the fingers 13 may be separate or integrated. If integrated, a switching mechanism for switching the output destination may be provided separately.

[0052] Next, the locations of each connecting part (first connecting part 42, second connecting part 52, and work section connecting part 14) in each link 7 described above will be explained in detail. First, with respect to the first link 11, the center of gravity G1 of the entire first link 11 is calculated in order to determine the placement of the first connecting portion 42. The center of gravity G1 of the first link 11 is calculated based on the weight of the first link 11, which includes the weight of the first link body 41, the weight of the first actuator 43, the weight of the first attached component 45, and the weight of the first transmission mechanism 46. The first connecting portion 42 is then placed at a position equivalent to the center of gravity G1 of the first link 11. Similarly, with respect to the second link 12, in determining the placement of the second connecting portion 52, the center of gravity G2 of the entire second link 12 is first calculated. The center of gravity G2 of the second link 12 is calculated based on the weight of the second link 12, which includes the weight of the second link body 51, the weight of the second actuator 53, the weight of the second attached component 55 (i.e., the working portion 8), and the weight of the second transmission mechanism. The second connecting portion 52 is then placed at a position equivalent to the center of gravity G2 of the second link 12. Similarly, with respect to the work section 8, the work section connecting section 14 is provided at a position equivalent to the center of gravity position G3 of the work section 8.

[0053] Furthermore, the phrase "position equivalent to the center of gravity" in the claim is not limited to cases where the center of gravity positions G1, G2 of each link 7 and the corresponding positions of each connecting portion 82 (or corresponding pivot axis OX) perfectly coincide, but also includes cases where the connecting portion 82 is provided in the vicinity of the center of gravity positions G1, G2. As an example of "in the vicinity," for example, the first connecting portion 42 may be provided at least between the center of gravity (or output axis) of the first actuator 43 and the center of gravity position G1 of the first link 11.

[0054] As shown in Figure 1, the control unit 5 is provided on the robot body 2. The control unit 5 controls the actuator 83 that drives the arm 4 and the thruster 3 described above, respectively. The control unit 5 has an attitude control unit. The attitude control unit controls the attitude of the robot 1 by changing at least one of the center of gravity and center of buoyancy by moving the buoyancy member of the moving member 18 along the X-axis direction or the Y-axis direction (or both).

[0055] Figure 6 is a control flow diagram of the control unit 5. As shown in Figure 6, in addition to controlling the posture of the robot 1 as described above, the control unit 5 determines whether or not the work unit 8 is gripping an object, and performs switching control to enable or disable posture control based on the determination result. In switching control, first, it is determined whether or not the work unit 8 is gripping an object (step ST01). The determination in step ST01 is performed repeatedly, for example, at a predetermined time period. The determination of whether or not an object is being gripped in step ST01 is made, for example, based on the output result of a pressure sensor provided on the finger 13 of the work unit 8. For example, the control unit 5 determines that an object is being gripped when the output value of the pressure sensor exceeds a predetermined threshold. As another example, the control unit 5 may acquire the load of the motor 16 that moves the finger 13 and determine whether or not an object is being gripped based on the acquired load value.

[0056] If it is determined in step ST01 that the work unit 8 is not gripping an object (NO in STEP01), the process proceeds to step ST03. In step ST03, the attitude control described above is disabled and the flow ends. In other words, the attitude control unit waits without performing attitude control.

[0057] On the other hand, if it is determined in step ST01 that the work unit 8 is gripping an object (YES in STEP01), the process proceeds to step ST02. In step ST02, the attitude control described above is switched on and the process ends. When attitude control is enabled, the attitude control unit performs attitude control. When attitude control is enabled, the attitude control unit detects the current attitude of robot 1 and moves the moving member 18 so that the detected current attitude matches a preset (or calculated) target attitude. In this way, it controls the robot to maintain a constant attitude.

[0058] In the robot 1 of this embodiment, the arm 4 includes a link body 81, a connecting part 82, and an actuator 83. By rotating the link body 81 around the connecting part 82, the arm 4 (or the work part 8 provided at the tip of the arm 4) can be extended or bent relative to the robot body 2. The connecting part 82 is positioned in the longitudinal direction of the link 7 at a position equivalent to the center of gravity positions G1 and G2 of the link 7. This makes it possible to reduce the amount of change in the center of gravity position of the entire arm 4 even when the arm 4 is extended or bent due to the rotation of the link body 81. In particular, when the position of the connecting part 82 coincides with the center of gravity positions G1 and G2 of the link 7, the center of gravity position of the entire arm 4 remains unchanged regardless of whether the arm 4 is extended or bent. Therefore, compared to conventional technology in which attitude control is performed each time the arm 4 is extended or bent, the energy consumption related to attitude control can be kept low. Furthermore, even when the connecting portion 82 is installed near the center of gravity positions G1 and G2 of the link 7 (i.e., the position of the connecting portion 82 and the center of gravity positions G1 and G2 of the link 7 do not perfectly coincide), energy consumption can be kept low compared to the conventional technology. Generally, when an arm portion 4 is constructed using a link mechanism, the connecting portion 82 (the pivot axis OX of the link 7) is often installed near the base end of the link 7 in order to maximize the range of motion of the arm portion 4. In other words, in the conventional technology, which does not consider the center of gravity position, the connecting portion 82 is often installed at a position far from the center of gravity positions G1 and G2 of the link 7. In contrast, according to an embodiment of the present invention, by installing the connecting portion 82 near the center of gravity positions G1 and G2 of the link 7, the change in posture associated with the extension or flexion of the arm portion 4 can be reduced compared to the conventional technology in which the connecting portion 82 is installed at a position far from the center of gravity positions G1 and G2 of the link 7. Therefore, the energy consumption related to posture control can be reduced. Therefore, we can provide a robot 1 that can keep energy consumption low compared to conventional technology.

[0059] Since the arm section 4 has two links 7, a first link 11 and a second link 12, a large range of motion can be secured by rotating each link 7 around its pivot axis OX, allowing for extension or flexion of the arm section 4. Furthermore, since the connecting portion 82 of each link 7 is positioned at the same location as the center of gravity positions G1 and G2 of each link 7, even when using multiple links 7, the change in the overall center of gravity position of the arm section 4 due to extension or flexion can be kept small. Thus, the usability of the robot 1 can be improved while reducing energy consumption.

[0060] The actuator 83 is located on the base end 11b, 12b side of the link body 81 in the longitudinal direction of the link 7, rather than on the connecting portion 82. Since the heavy actuator 83 is located on the base end 11b, 12b side of the link body 81, it becomes easier to balance the weight with the attached parts 45, 55 located on the tip end 11a, 12a side of the link 7. In addition, by placing the actuator 83 on the base end 11b, 12b side, the center of gravity positions G1, G2 of the link 7 can be positioned on the base end 11b, 12b side in the longitudinal direction of the link body 41, 51. As a result, the connecting portion 82 can be located on the base end 11b, 12b side, which allows for a larger range of motion of the arm portion 4 due to the rotation of the link 7 compared to the case where the connecting portion 82 is located on the tip side. Thus, the versatility of the robot 1 can be improved while suppressing energy consumption related to attitude control.

[0061] Robot 1 further includes a transmission mechanism 46 which includes a first gear 65 connected to the output shaft of actuator 83 and a second gear 66 that transmits the rotational force from the first gear 65 to the connecting part 82. This allows the output from actuator 83 to be transmitted to the connecting part 82 via multiple gears. Therefore, actuator 83 can be placed at any position. This makes it easier to adjust the center of gravity positions G1 and G2 of link 7, improving the versatility of robot 1.

[0062] The control unit 5, located in the robot body 2, switches between enabling and disabling posture control based on whether or not the work unit 8 (hand) is grasping an object. For example, if the work unit 8 is not grasping an object, posture control is disabled. This reduces unnecessary energy consumption related to posture control. When it is detected that the work unit 8 has grasped an object, posture control is enabled. This allows appropriate posture control to be performed in response to changes in the center of gravity of the arm unit 4. Thus, the posture of the robot 1 can be maintained while minimizing energy consumption.

[0063] Next, the second to fourth embodiments of the present invention will be described with reference to Figures 7 to 13. In the second to fourth embodiments, the configuration of the transmission mechanism mainly differs from that of the first embodiment described above. In the following description, the configuration of the first transmission mechanism 46 provided on the first link 11 will be described as an example of the repertoire of transmission mechanisms, and the description of the second transmission mechanism provided on the second link 12 will be omitted. The second transmission mechanism may be equivalent in configuration to the first transmission mechanism 46, or it may have a different configuration from the first transmission mechanism 46.

[0064] (Second Embodiment) First, a second embodiment of the present invention will be described. Figure 7 is a front view showing the configuration of the transmission mechanism 263 according to the second embodiment. Figure 8 is a side view showing the configuration of the transmission mechanism 263 according to the second embodiment. As shown in Figures 7 and 8, in the second embodiment, the first actuator 43 is provided coaxially with the first pivot shaft O1 (first connecting portion 42). The first transmission mechanism 263 is a planetary gear having, for example, a sun gear 264 connected to the output shaft of the first actuator 43 and an outer gear 265 connected to the first link body 41. Furthermore, in this embodiment, a buoyancy body 261 is provided on the tip end 11a side of the first actuator 43 in the longitudinal direction of the first link body 41. Also, a counterweight 262 is provided on the base end 11b side of the first actuator 43 in the longitudinal direction of the first link body 41.

[0065] According to the robot 1 of the second embodiment, the first actuator 43 and the first connecting portion 42 can be arranged coaxially. Therefore, the versatility of the transmission mechanism 263 can be improved. Furthermore, a buoyancy body 261 is provided on the tip 11a side of the link body 41. This increases the buoyancy on the tip 11a side of the first link 11, especially when the robot 1 is working underwater, making it easier to adjust the overall weight balance of the first link 11. Also, by making the tip 11a of the first link 11 lighter, the center of gravity G1 of the first link 11 can be positioned relatively closer to the base end 11b in the longitudinal direction of the link body 41. This allows the connecting part 42 to be provided on the base end 11b side, and a larger range of motion of the arm part 4 due to the rotation of the first link 11 can be secured. Thus, the versatility of the robot 1 can be improved. Furthermore, this configuration is particularly suitable for a robot 1 that works underwater.

[0066] A counterweight 262 is provided on the base end 11b side of the link body 41. This makes it easy to increase the weight of the base end 11b side of the first link 11, and makes it easier to adjust the overall weight balance of the first link 11. In addition, since the center of gravity position G1 of the first link 11 can be positioned closer to the base end 11b in the longitudinal direction of the link body 41, a large range of motion of the arm section 4 due to the rotation of the first link 11 can be secured. Thus, the versatility of the robot 1 can be improved.

[0067] (Third embodiment) Next, a third embodiment of the present invention will be described. Figure 9 is a front view showing the configuration of the transmission mechanism 363 according to the third embodiment. Figure 10 is a side view showing the configuration of the transmission mechanism 363 according to the third embodiment. As shown in Figures 9 and 10, in the third embodiment, the first actuator 343 has an output shaft extending in the X-axis direction. The first transmission mechanism 363 includes a first bevel gear 365 and a second bevel gear 366. The first bevel gear 365 is connected to the output shaft of the first actuator 343 and rotates around a rotation axis along the X-axis. The second bevel gear 366 is connected to the first coupling portion 42 and rotates around a rotation axis (first rotation axis O1) along the Z-axis direction.

[0068] Figure 11 is a side view showing the configuration of a transmission mechanism 364 according to a modified example of the third embodiment. As shown in Figure 11, in a modified example of the third embodiment, the first actuator 344 is positioned at an inclination such that it forms a predetermined inclination angle θ with the X axis when viewed from the Y axis direction. The first transmission mechanism 364 includes a first gear 367 and a second bevel gear 368. The first gear 367 is connected to the output shaft of the first actuator 344. The second bevel gear 368 is connected to the first coupling portion 42. The second bevel gear 368 is a bevel gear having a tapered surface corresponding to the inclination angle θ.

[0069] According to the third embodiment and modified robot 1, at least some of the multiple gears are bevel gears. This makes it possible to create a suitable configuration when the output shafts of actuators 343 and 344 intersect with the rotation axis O1 of the first link 11. Thus, the versatility of robot 1 can be improved.

[0070] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. Figure 12 is a front view showing the configuration of the transmission mechanism 463 according to the fourth embodiment. Figure 13 is a side view showing the configuration of the transmission mechanism 463 according to the fourth embodiment. As shown in Figures 12 and 13, in the fourth embodiment, the first actuator 43 is provided on the base end 11b side of the first connecting portion 42. The first transmission mechanism 463 includes a drive pulley 471, a passive pulley 472, and a belt 475. The drive pulley 471 is connected to the output shaft of the first actuator 43 and rotates integrally with the output shaft. The passive pulley 472 is connected to the first connecting portion 42. The belt 475 is stretched between the drive pulley 471 and the passive pulley 472 and transmits output from the drive pulley 471 to the passive pulley 472.

[0071] According to the robot 1 of the fourth embodiment, the output shaft of the first actuator 43 and the first pivot shaft O1 (first connecting part 42) can be connected by the belt 475. Therefore, the versatility of the robot 1 can be improved.

[0072] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in the first embodiment described above, the switching control flow shown in Figure 6 is executed repeatedly at a predetermined time interval, but the configuration is not limited to this. For example, the control unit 5 may periodically acquire the output value from the pressure sensor of the finger 13 and execute the flow in Figure 6 when this output value crosses a predetermined threshold.

[0073] The number of links 7 in the arm section 4 is not limited to two. In the first embodiment, the number of gears in the first transmission mechanism 46 is not limited to four. For example, the first transmission mechanism 46 may have only two gears: a first gear connected to the output shaft of the first actuator 43, and a second gear (neither shown) connected to the first connecting shaft and meshing with the first gear. Alternatively, the configuration of the transmission mechanism may be a combination of the configurations of the embodiments described above. The center of gravity positions G1 and G2 may be adjusted by methods other than providing counterweights 262 and buoyancy bodies 261. For example, the center of gravity positions G1 and G2 may be adjusted by changing the plate thickness or shape of the link body 81.

[0074] In the embodiments described above, a robot 1 performing work underwater was used as an example of the robot 1, but the working environment is not limited to this. The present invention may also be applied to a robot 1 performing work in an environment other than underwater (for example, on land). In this case, instead of providing a buoyancy body 261, a weight-reducing section or a low-density lightweight member may be provided. The shape of the work unit 8 is not limited to the shape shown in the illustration. Other examples of the work unit 8 include, for example, a device that generates a water flow (or wind) using a propeller for cleaning, a camera for taking pictures underwater, or a known flaw detection sensor for non-destructively inspecting defects such as cracks or corrosion present near the surface of a conductive material such as metal.

[0075] Furthermore, without departing from the spirit of the present invention, the components in the embodiments described above may be replaced with well-known components, and the embodiments described above may be combined as appropriate. [Explanation of Symbols]

[0076] 1 Robot 2. Robot body 3. Thruster (propulsion unit) 4. Arm section 5. Control Unit 7 links 8. Work Section 11. First Link (Link) 12. Second Link (Link) 11a,12a Tip 11b,12b Base end 13 Fingers 41. First Link Body (Link Body) 42 First connection part (connection part) 43,343,344 First Actuator (Actuator) 45. First part to be attached (part to be attached) 46. ​​First transmission mechanism (transmission mechanism) 51 Second Link Body (Link Body) 52 Second connection part (connection part) 53 Second Actuator (Actuator) 55 Second part to be attached (part to be attached) 65 First gear 66 Second gear 81 Link Body 82 Connecting part 83 Actuator 261 Buoyancy device 262 Counterweight 263,363,364,463 Transmission mechanism 471 Drive pulley 472 Passive pulley 475 belt G1,G2 Center of gravity position O1 First pivot axis (rotating axis) O2 Second pivot shaft (rotating shaft) OX Rotary shaft

Claims

1. The robot body and The propulsion unit that drives the robot body, An arm section connected to the robot body, having one or more links and a working section provided at the tip of the link, An actuator that drives the arm portion and a control unit that controls the propulsion portion, Equipped with, The aforementioned link is The link itself and A connecting portion that connects the link body to the robot body so that it can rotate around a pivot axis, The actuator is attached to the link body and rotates the link body around the pivot axis, It has, The connecting portion is provided in the longitudinal direction of the link at a position equivalent to the center of gravity of the link, including the link body, the actuator, and the part to be attached to the tip of the link body. robot.

2. The aforementioned link has a first link and a second link, The aforementioned first link is, The first link body and A first connecting part that connects the robot body and the first link body so that they can rotate around a first pivot axis, The first link is rotated around the first pivot axis by a first actuator, The second link mentioned above is, A second link body connected to the tip of the first link body, A second connecting portion that connects the tip of the first link body and the second link body so as to be rotatable around a second pivot axis, The second link is rotated around the second pivot axis by a second actuator, The tip of the second link body is provided with the work section, The first connecting portion is provided in the longitudinal direction of the first link at a position equivalent to the center of gravity of the first link, which includes the first link body, the first actuator, and the first mounting component attached to the tip of the first link body. The second connecting portion is provided in the longitudinal direction of the second link at a position equivalent to the center of gravity of the second link, which includes the second link body, the second actuator, and the working portion attached to the tip of the second link body. The robot according to claim 1.

3. The actuator is provided on the base end side of the link, which is located in the longitudinal direction of the link, on the side opposite to the tip end to which the component to be attached is mounted, The robot according to claim 1.

4. The link further includes a buoyancy body provided in the longitudinal direction of the link, on the tip side of the link rather than the connecting portion. Performing work underwater, The robot according to claim 1.

5. The link further includes a counterweight provided on the base end side of the link, which is located on the side opposite to the tip end to which the component to be attached is attached, in the longitudinal direction of the link. The robot according to claim 1.

6. The transmission mechanism further includes a first gear connected to the output shaft of the actuator, and a second gear connected to the first gear for transmitting rotational force from the first gear to the connecting part. The robot according to claim 1.

7. At least one of the first gear and the second gear is a bevel gear. The robot according to claim 6.

8. The transmission mechanism further includes a drive pulley connected to the output shaft of the actuator, a passive pulley connected to the connecting portion, and a belt that transmits output from the drive pulley to the passive pulley. The robot according to claim 1.

9. The control unit includes an attitude control unit that controls the attitude of the robot by changing at least one of the center of gravity and the center of buoyancy by moving the buoyancy member. The aforementioned working part is a hand having multiple fingers, The control unit determines whether the hand is grasping an object, and switches the posture control on and off based on the determination result. The robot according to any one of claims 1 to 8.

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