Floating unit

Abstract

To provide a floating unit which performs movement of a second component relative to a first component in every posture.SOLUTION: In a floating unit 100, a movable support mechanism 3 which so supports a first component 1 and a second component 2 as to be relatively movable, comprises N telescopic cylinders 4 (N is a natural number of 3 or more). Each telescopic cylinder 4 comprises a stem 41, a movable part 42, and a drive part 43 for driving the movable part 42. Each stem 41 comprises a first connection part 51 which is connected to the first component 1 via a first ball joint 61, each movable part 42 comprises a second connection part 52 which is connected to the second component 2 via a second ball joint 62, N first connection parts 51 are located along a first reference circle, and N second connection parts 52 are located along a second reference circle. Each movable part 42 is provided with a load sensor 7 which detects an expansion and contraction load in the movable part 42, and a control part controls the drive part 43 on the basis of a detection value of the load sensor 7.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a floating unit configured such that a second member is relatively movable with respect to a first member.

Background Art

[0002] An example of such a floating unit is disclosed in Patent Document 1 below. In the following explanations of the "Background Art" and the "Problems to be Solved by the Invention", the reference numerals in Patent Document 1 are cited within parentheses.

[0003] The floating unit of Patent Document 1 includes a first member (1) and a second member (2) that are spaced apart from each other, and a plurality of fluid pressure cylinders (3) that connect them (see FIG. 1 of Patent Document 1). Each of the plurality of fluid pressure cylinders (3) includes a cylindrical base portion (30) and a rod-shaped movable portion (31) that is supported so as to be able to expand and contract with respect to the base portion. The end portion of the base portion (30) on the side opposite to the side of the movable portion (31) is connected to the first member (1) via a universal joint (4). And the end portion of the movable portion (31) on the side opposite to the side of the base portion (30) is connected to the second member (2) via a ball joint (5). With such a structure, when an external force is applied to the second member (2), the second member moves relatively with respect to the first member (1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the floating unit of Patent Document 1 is attached to the tip of a robot arm (R) and the work of assembling the first part (W1), which is held by the second member (2), to the second part (W2), which is fixed in a predetermined position, is performed (see Figure 4 of Patent Document 1), for example, when the second member (2) and the first part (W1) are aligned horizontally, their weight makes it difficult to move the second member (2) upward relative to the first member (1) compared to the downward relative movement of the second member (2) relative to the first member (1).

[0006] Thus, depending on its orientation, the floating unit of Patent Document 1 may have difficulty in relative movement of the second member (2) to the first member (1).

[0007] Therefore, it is desirable to realize a floating unit that allows for easy relative movement of the second member relative to the first member in any orientation. [Means for solving the problem]

[0008] In light of the above, the characteristic configuration of the floating unit is: A first member and a second member are arranged spaced apart from each other, A movable support mechanism that supports the first member and the second member such that the second member moves relative to the first member, The system comprises a control unit for controlling the movable support mechanism, The aforementioned movable support mechanism comprises N telescopic cylinders (where N is a natural number greater than or equal to 3), Each of the N telescopic cylinders comprises a base, a movable part supported to extend and retract relative to the base, and a drive unit for driving the movable part. Each of the N bases is provided with a first connecting portion connected to the first member via a first ball joint, Each of the N movable parts is provided with a second connecting part connected to the second member via a second ball joint, The N first connecting parts are arranged along the first reference circle, The N of the aforementioned second connecting parts are arranged along the second reference circle, Each of the N movable parts , this The movable part Okeru Load in the direction of expansion and contraction Weight A load sensor is provided to detect the load. The control unit, Based on the detected values ​​from the N load sensors, control the N drive units. death, Floating control is performed to cause the drive unit to output a thrust force equal in magnitude to the expansion and contraction load acting on each of the N movable parts, in the opposite direction to the direction of the expansion and contraction load acting on each of the N movable parts due to the weight of the second member acting on each of the N movable parts and the weight of the equipment attached to the second member; and centering control is performed to expand and contract the N movable parts so that the second member returns to a reference position relative to the first member during the execution of the floating control. The direction along the axis of the first reference circle is defined as the axial direction, the direction perpendicular to the axis of the first reference circle is defined as the radial direction, and the direction along the first reference circle is defined as the circumferential direction. The second member is configured to be able to perform relative movement in the axial direction relative to the first member, relative movement in the radial direction relative to the first member, relative movement in the circumferential direction relative to the first member, and at least two of these combined movements, via N first connecting parts and N second connecting parts. It's at a single point.

[0009] With this configuration, the expansion and contraction load acting on each of the N movable parts is detected using load sensors. Based on the expansion and contraction loads detected by the N load sensors, N drive units output thrust to drive the N movable parts. This allows the N drive units to output thrust in a way that reduces the expansion and contraction load acting on the N movable parts. Therefore, relative movement of the second member with respect to the first member can be easily performed regardless of the orientation of the floating unit. Furthermore, this feature configuration allows the N drive units to output thrust in a manner that counteracts the expansion and contraction loads acting on the N movable parts. This makes it possible to equalize the loads acting on the second member via the N second connecting parts, regardless of the orientation of the floating unit. Consequently, the relative movement of the second member with respect to the first member can be made even easier. Furthermore, with this feature configuration, in floating control, if the second member moves to a position deviating from the reference position relative to the first member, centering control can be performed to return the second member to the reference position relative to the first member. [Brief explanation of the drawing]

[0010] [Figure 1] Perspective view of the floating unit according to the embodiment [Figure 2] Plan view of the floating unit according to the embodiment [Figure 3] Control block diagram of the floating unit according to the embodiment [Figure 4] Diagram showing the structure of the telescopic cylinder and its surroundings. [Figure 5] Plan view showing the state in which the second member 2 has moved radially from its reference position. [Figure 6] Plan view showing the state in which the second member 2 has moved circumferentially from its reference position. [Figure 7] Side view showing the state in which the second member 2 has moved axially from its reference position. [Figure 8] Schematic diagram showing the detachable equipment provided with the floating unit according to the embodiment

Embodiments for Carrying out the Invention

[0011] Hereinafter, the floating unit 100 according to the embodiment will be described with reference to the drawings. As shown in FIGS. 1 and 2, the floating unit 100 includes a first member 1 and a second member 2 arranged apart from each other, and a movable support mechanism 3 that supports the first member 1 and the second member 2 so that the second member 2 moves relative to the first member 1.

[0012] As shown in FIG. 1, in the present embodiment, the first member 1 is formed in an annular plate shape. In the following description, the "axial direction L", the "radial direction R", and the "circumferential direction C" are defined based on the axis of the first member 1.

[0013] The axial direction L is the direction along the axis of the first member 1. The radial direction R is the direction orthogonal to the axial direction L and extending radially from the axis of the first member 1. The circumferential direction C is the direction along the circumference centered on the axis of the first member 1. In the following description, one side of the axial direction L is referred to as the "first axial side L1", and the other side of the axial direction L is referred to as the "second axial side L2". Also, in the radial direction R, the side closer to the axis of the first member 1 is referred to as the "inner radial side R1", and the opposite side is referred to as the "outer radial side R2".

[0014] In this embodiment, the second member 2 is formed in the shape of a rectangular plate. The second member 2 is positioned radially inward R1 from the first member 1 when it is located at a reference position P1 relative to the first member 1. Here, the reference position P1 is the relative position of the second member 2 with respect to the first member 1 when no external force is applied to the second member 2. In this embodiment, the reference position P1 is the relative position of the second member 2 with respect to the first member 1 when the axis of the first member 1 and the axis of the second member 2 are aligned. In other words, in this embodiment, when the second member 2 is at the reference position P1, the first member 1 and the second member 2 are coaxial. The axis of the first member 1 here is the axis of the first reference circle C1, which will be described later, and the axis of the second member 2 is the axis of the second reference circle C2, which will be described later.

[0015] The movable support mechanism 3 is equipped with N telescopic cylinders 4 (where N is a natural number greater than or equal to 3). In this embodiment, the movable support mechanism 3 is equipped with 4 telescopic cylinders 4 (N=4).

[0016] Each of the N telescopic cylinders 4 comprises a base 41, a movable part 42 that is supported to extend and retract relative to the base 41, and a drive unit 43 that drives the movable part 42.

[0017] In this embodiment, each telescopic cylinder 4 is a so-called electric cylinder. Specifically, the base 41 is formed in a cylindrical shape. The movable part 42 extends along the axis of the base 41 and is positioned inside the base 41 such that one end is exposed to the outside. Here, the movable part 42 is a cylindrical member. The drive unit 43 is a power transmission mechanism that includes a ball screw connected to the movable part 42 and a motor that rotates the ball screw. In this way, the motor of the drive unit 43 rotates the ball screw, causing the movable part 42 to move so as to extend and retract relative to the base 41. In this example, the movable part 42 is a screw shaft with screw threads formed on its outer surface, and the drive unit 43 rotates a ball screw nut that is screwed into the screw threads using the motor, thereby causing the movable part 42 to protrude or retract relative to the base 41.

[0018] Each of the N base portions 41 is provided with a first connecting portion 51. The first connecting portion 51 is connected to the first member 1 via a first ball joint 61. In this embodiment, the first connecting portion 51 is provided at the end of the base portion 41 opposite to the side of the movable portion 42.

[0019] The first ball joint 61 is a joint that connects the first member 1 and the base 41 such that the base 41 swings relative to the base 41 in all directions. The first ball joint 61 comprises a first spherical body 61a having a spherical tip and a first support 61b that pivotably supports the spherical tip of the first spherical body 61a. In this embodiment, the first spherical body 61a is provided so as to protrude from the surface of the first axial side L1 of the first member 1. The first support 61b is provided so as to protrude from the end face of the base 41 (first connecting portion 51) opposite to the side of the movable portion 42.

[0020] Each of the N movable parts 42 is provided with a second connecting part 52. The second connecting part 52 is connected to the second member 2 via a second ball joint 62. In this embodiment, the second connecting part 52 is provided on the portion of the movable part 42 that is exposed to the outside on the side opposite to the base part 41. In this example, the second connecting part 52 is provided at the tip of the portion of the movable part 42 that is exposed to the outside from the base part 41.

[0021] The second ball joint 62 is a joint that connects the second member 2 so that the movable part 42 can swing relative to the second member 2 in all directions. The second ball joint 62 comprises a second spherical body 62a having a spherical tip, and a second support 62b that pivotably supports the spherical tip of the second spherical body 62a. In this embodiment, the second spherical body 62a is provided so as to protrude from the surface of the first axial side L1 of the second member 2. The second support 62b is fixed to the tip of the portion of the movable part 42 that is exposed to the outside from the base 41.

[0022] As shown in Figure 2, the N first connecting parts 51 are arranged along the first reference circle C1. In this embodiment, four first connecting parts 51 are arranged at equal intervals along the first reference circle C1. The N second connecting parts 52 are arranged along the second reference circle C2. In this embodiment, four second connecting parts 52 are arranged at equal intervals along the second reference circle C2.

[0023] The first reference circle C1 and the second reference circle C2 are both virtual circles. In this embodiment, the first reference circle C1 and the second reference circle C2 are arranged along the circumferential direction C when the second member 2 is at the reference position P1. In other words, the first reference circle C1 is arranged coaxially with the first member 1 (the axis of the first member 1). Also, when the second member 2 is at the reference position P1, the second reference circle C2 is also arranged coaxially with the first member 1 (the axis of the first member 1).

[0024] Furthermore, in this embodiment, the second reference circle C2 has a smaller diameter than the first reference circle C1 and is located radially inward R1 from the first reference circle C1. In other words, in this embodiment, each telescopic cylinder 4 is positioned such that its base 41 is located radially outward R2 relative to the movable part 42. Also, in this embodiment, each telescopic cylinder 4 is positioned such that, with the second member 2 in the reference position P1, it is oriented along the radial direction R.

[0025] Each of the N movable parts 42 is provided with a load sensor 7 that detects the expansion / contraction load F1 (see Figure 4), which is the load in the expansion / contraction direction of the movable part 42. The load sensor 7 is a sensor capable of detecting both tensile and compressive loads. In this embodiment, the load sensor 7 is a force sensor that measures the force in each axial direction in three-dimensional space and the force rotating around each axis.

[0026] In this embodiment, each load sensor 7 is positioned closer to the second connecting portion 52 than to the center of the movable portion 42 in the extension and contraction direction. In other words, in this embodiment, each load sensor 7 is positioned relatively close to the second connecting portion 52 in the movable portion 42. In the illustrated example, each load sensor 7 is positioned adjacent to the second connecting portion 52.

[0027] As shown in Figure 3, the floating unit 100 includes a control unit 10 that controls the movable support mechanism 3.

[0028] The control unit 10 controls N drive units 43 based on the detected values ​​of N load sensors 7. As shown in Figure 4, in this embodiment, the control unit 10 performs floating control, causing the corresponding drive unit 43 to output a thrust F2 of the same magnitude as the expansion / contraction load F1 acting on each movable part 42, in the opposite direction to the expansion / contraction load F1 acting on each movable part 42. In other words, in floating control, the control unit 10 causes the corresponding drive unit 43 to output a thrust F2 in such a way as to cancel out the expansion / contraction load F1 acting on each movable part 42. This makes it possible to make the loads acting on the second member 2 via the N second connecting parts 52 equal to each other, regardless of the orientation of the floating unit 100.

[0029] The expansion / contraction load F1 is a load in the expansion / contraction direction that acts on each movable part 42 due to the weight of the second member 2 and the weight of the equipment attached to the second member 2, etc., when no external force (excluding forces caused by gravity) is applied to the second member 2. Therefore, the expansion / contraction load F1 changes for each movable part 42 depending on the posture of the floating unit 100. Floating control is performed to achieve a floating state in which the position of the second member 2 moves in accordance with the external force applied to the second member 2. Therefore, floating control is performed even when no external force is applied to the second member 2.

[0030] Figure 4 shows the configuration of the telescopic cylinder 4 and its surroundings, located above the second member 2, when the floating unit 100 is in a position where its axial direction L is perpendicular to the vertical direction. In the example shown in Figure 4, the telescopic load F1 acts in the direction from the telescopic cylinder 4 toward the second member 2. In response, during the execution of floating control, the drive unit 43 outputs a thrust F2 of the same magnitude as the telescopic load F1 in the direction that the movable part 42 moves toward the base 41.

[0031] In this embodiment, the control unit 10 performs lock control to fix the relative position of each movable part 42 with respect to the base 41 in the extension and retraction direction. During lock control, the control unit 10 causes the drive unit 43 to output a thrust force that cancels out all external forces acting on the movable part 42 from the second member 2, so that the movable part 42 does not move in the extension and retraction direction relative to the base 41 in each of the N extension and retraction cylinders 4. Alternatively, if each drive unit 43 is equipped with a brake mechanism or lock mechanism (not shown), the control unit 10 activates the brake mechanism or lock mechanism to fix each movable part 42 so that it does not move in the extension and retraction direction relative to the base 41.

[0032] In this embodiment, the control unit 10 performs centering control to extend and retract each movable part 42 so that the second member 2 returns to the reference position P1. In centering control, the control unit 10 drives the drive unit 43 to move the movable part 42 in each of the N telescopic cylinders 4 so that the movable part 42 is in a reference position in the extension and retraction direction relative to the base 41.

[0033] Figure 5 shows the state where a radial force R is applied to the second member 2 at the reference position P1, causing the second member 2 to move radially outward R2 from the reference position P1 to the radially moved position P2. Figure 6 shows the state where a circumferential force C is applied to the second member 2 at the reference position P1, causing the second member 2 to move relative to the first member 1 in the circumferential direction C, that is, to rotate around the axis of the first member 1, to the circumferential moved position P3. Figure 7 shows the state where an axial force L is applied to the second member 2 at the reference position P1, causing the second member 2 to move axially to the first side L1 from the reference position P1 to the axially moved position P4. Note that the movement of the second member 2 to each of these positions is achieved by applying external forces in each direction to the second member 2 while the floating control is being performed by the control unit 10.

[0034] When lock control is performed with the second member 2 positioned at each of these positions P2 to P4, the second member 2 is fixed at each of these positions P2 to P4. Also, when centering control is performed with the second member 2 positioned at each of these positions P2 to P4, the second member 2 moves relative to the first member 1 so as to return to the reference position P1.

[0035] Furthermore, when floating control is in operation, the second member 2 can move to any position, not limited to the above-mentioned positions P2 to P4. Specifically, the second member 2 is capable of not only relative movement in the radial direction R relative to the first member 1, relative movement in the circumferential direction C relative to the first member 1, and relative movement in the axial direction L relative to the first member 1, but also movements that combine at least two of these.

[0036] As shown in Figure 8, in this embodiment, as an example, the floating unit 100 is provided in a detachable equipment 20 for attaching and detaching specified parts.

[0037] The attachment / detachment equipment 20 includes a gripping device 21 for gripping parts and a multi-joint robot arm 22. The gripping device 21 is attached to the second member 2 of the floating unit 100. In this embodiment, the gripping device 21 is attached to the surface of the first axial side L1 of the second member 2. The tip of the robot arm 22 is attached to the first member 1 of the floating unit 100. In this embodiment, the tip of the robot arm 22 is attached to the surface of the second axial side L2 of the first member 1. By controlling the robot arm 22, the gripping device 21 can be moved to a desired position and adjusted to a desired angle within the operating range of the robot arm 22.

[0038] In this embodiment, when the gripping device 21, which is gripping a component, performs an installation operation to attach the component to a designated mounting target, floating control is performed from just before the start of the installation operation until the positioning of the component on the mounting target is completed. Similarly, when the gripping device 21 performs a removal operation to remove a component attached to the mounting target, floating control is performed from just before the start of the removal operation until the gripping device 21 completes gripping the component attached to the mounting target. Immediately after the end of the floating control, the control unit 10 performs lock control. This allows the subsequent installation and removal operations to be performed while maintaining the position of the gripping device 21 determined during the floating control. Depending on the shape of the component and mounting target, floating control may be performed until the completion of the installation operation and until the completion of the removal operation.

[0039] [Other Embodiments] (1) In the above embodiment, the configuration in which the telescopic cylinder 4 is a so-called electric cylinder was described as an example. However, the configuration is not limited to such an example, and the telescopic cylinder 4 may be a hydraulic cylinder or a pneumatic cylinder, for example. In this case, the base portion 41 is a cylindrical cylinder tube, and the movable portion 42 is a piston that slides on the inner circumferential surface of the base portion 41. The drive unit 43 is a fluid supply device that supplies a fluid such as oil or air to the fluid pressure chamber formed between the base portion 41 (cylinder tube) and the movable portion 42 (piston).

[0040] (2) In the above embodiment, a configuration in which the movable support mechanism 3 is equipped with four telescopic cylinders 4 (N=4) was described as an example. However, the movable support mechanism 3 is not limited to such a configuration, and only needs to be equipped with at least three telescopic cylinders 4, and the number is not limited.

[0041] (3) In the above embodiment, a configuration was described as in which the second member 2 is in the reference position P1 and each telescopic cylinder 4 is positioned along the radial direction R. However, the configuration is not limited to this, and for example, the second member 2 may be in the reference position P1 and each telescopic cylinder 4 may be positioned along the axial direction L.

[0042] (4) In the above embodiment, a configuration in which the second reference circle C2 has a smaller diameter than the first reference circle C1 and is located radially inward R1 from the first reference circle C1 was described as an example. However, the configuration is not limited to this, and the second reference circle C2 may have a larger diameter than the first reference circle C1 and be located radially outward R2 from the first reference circle C1. In this case, each telescopic cylinder 4 is arranged such that the base portion 41 is located radially inward R1 from the movable portion 42. Alternatively, the first reference circle C1 and the second reference circle C2 may have the same diameter and be arranged so as to be aligned in the axial direction L. In this case, as described above, each telescopic cylinder 4 is arranged so as to be in a position along the axial direction L.

[0043] (5) In the above embodiment, the control unit 10 was described as having a configuration in which it outputs a thrust F2 of the same magnitude as the stretching load F1 acting on each movable part 42 in the opposite direction to the direction of the stretching load F1 acting on each movable part 42 during floating control to the corresponding drive unit 43. However, the configuration is not limited to such a configuration, and for example, the control unit 10 may output a thrust F2 that is smaller than the stretching load F1 acting on each movable part 42 in the opposite direction to the direction of the stretching load F1 acting on each movable part 42 during floating control to the corresponding drive unit 43.

[0044] (6) In the above embodiment, a configuration in which each load sensor 7 is positioned on the side of the second connecting portion 52 rather than the center of the movable portion 42 in the extension and contraction direction was described as an example. However, the configuration is not limited to such a configuration, and for example, each load sensor 7 may be positioned on the center of the movable portion 42 in the extension and contraction direction. Alternatively, each load sensor 7 may be positioned on the side of the base portion 41 rather than the center of the movable portion 42 in the extension and contraction direction.

[0045] (7) The configurations disclosed in each of the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0046] [Summary of the above embodiment] The following section provides an overview of the floating unit described above.

[0047] The floating unit is A first member and a second member are arranged spaced apart from each other, A movable support mechanism that supports the first member and the second member such that the second member moves relative to the first member, The system comprises a control unit for controlling the movable support mechanism, The aforementioned movable support mechanism comprises N telescopic cylinders (where N is a natural number greater than or equal to 3), Each of the N telescopic cylinders comprises a base, a movable part supported to extend and retract relative to the base, and a drive unit for driving the movable part. Each of the N bases is provided with a first connecting portion connected to the first member via a first ball joint, Each of the N movable parts is provided with a second connecting part connected to the second member via a second ball joint, The N first connecting parts are arranged along the first reference circle, The N of the aforementioned second connecting parts are arranged along the second reference circle, Each of the N movable parts is provided with a load sensor that detects the expansion / contraction load, which is the load in the expansion / contraction direction of the movable part. The control unit controls the N drive units based on the detected values ​​of the N load sensors.

[0048] In this configuration, the expansion and contraction load acting on each of the N movable parts is detected using load sensors. Based on the expansion and contraction loads detected by the N load sensors, N drive units output thrust to drive the N movable parts. This allows the N drive units to output thrust in a way that reduces the expansion and contraction load acting on the N movable parts. Therefore, relative movement of the second member with respect to the first member can be easily performed regardless of the orientation of the floating unit.

[0049] In this case, it is preferable for the control unit to perform floating control, which causes the drive unit to output a thrust force equal in magnitude to the expansion / contraction load acting on each of the N movable parts, in the opposite direction to the direction of the expansion / contraction load acting on each of the N movable parts.

[0050] This configuration allows the N drive units to output thrust in a manner that counteracts the expansion and contraction loads acting on the N movable parts. This makes it possible to equalize the loads acting on the second member via the N second connecting parts, regardless of the orientation of the floating unit. Consequently, the relative movement of the second member with respect to the first member can be made even easier.

[0051] Furthermore, it is preferable that the control unit performs lock control to fix the relative position of each of the N movable parts with respect to the base in the extension and retraction direction.

[0052] This configuration allows the second member to be fixed at any relative position to the first member. This makes it possible to switch between a floating control state in which the second member is movable relative to the first member, and a locked control state in which the second member is immovable relative to the first member.

[0053] Furthermore, it is preferable that the control unit performs centering control by extending or retracting the N movable parts so that the second member returns to a reference position relative to the first member.

[0054] With this configuration, in floating control, if the second member moves to a position deviating from the reference position relative to the first member, centering control can be performed to return the second member to the reference position relative to the first member.

[0055] Furthermore, it is preferable that each of the N load sensors is positioned on the side of the second connecting portion rather than the center of the movable portion in the extension and contraction direction.

[0056] In this configuration, each of the N load sensors is positioned relatively close to the second connecting portion in the movable part. This minimizes the influence of the weight of the movable part on the expansion and contraction load detected by the load sensors. Therefore, the expansion and contraction load can be accurately detected by the load sensors. [Industrial applicability]

[0057] The technology disclosed herein can be used in a floating unit in which a second member is configured to be relatively movable relative to a first member. [Explanation of Symbols]

[0058] 100: Floating Unit 1: First member 2: Second member 3: Movable support mechanism 4: Expandable cylinder 41: Base 42: Moving part 43: Drive unit 51: 1st connection part 52:Second connection part 61: First ball joint 62: Second ball joint 7: Load sensor 10: Control Unit C1: First reference circle C2: Second base yen F1: Expansion load

Claims

1. A first member and a second member are arranged spaced apart from each other, A movable support mechanism that supports the first member and the second member such that the second member moves relative to the first member, The system comprises a control unit for controlling the movable support mechanism, The aforementioned movable support mechanism comprises N telescopic cylinders (where N is a natural number of 3 or more), Each of the N telescopic cylinders comprises a base, a movable part supported to extend and retract relative to the base, and a drive unit for driving the movable part. Each of the N bases is provided with a first connecting portion connected to the first member via a first ball joint, Each of the N movable parts is provided with a second connecting part connected to the second member via a second ball joint, The N first connecting parts are arranged along the first reference circle, The N second connecting parts are arranged along the second reference circle, Each of the N movable parts is provided with a load sensor that detects the load in the expansion and contraction direction of the movable part. The control unit, Based on the detected values ​​of the N load sensors, the N drive units are controlled. The system performs floating control, which causes the drive unit to output a thrust force equal in magnitude to the expansion / contraction load acting on each of the N movable parts, in the opposite direction to the direction of the expansion / contraction load acting on each of the N movable parts due to the weight of the second member acting on each of the N movable parts and the weight of the equipment attached to the second member, and centering control, which causes the N movable parts to expand and contract so that the second member returns to a reference position relative to the first member during the execution of the floating control. The direction along the axis of the first reference circle is defined as the axial direction, the direction perpendicular to the axis of the first reference circle is defined as the radial direction, and the direction along the first reference circle is defined as the circumferential direction. A floating unit in which the second member is configured to be able to perform relative movement in the axial direction relative to the first member, relative movement in the radial direction relative to the first member, and relative movement in the circumferential direction relative to the first member, as well as at least two of these combined movements, via N first connecting parts and N second connecting parts.

2. The floating unit according to claim 1, wherein the control unit performs lock control to fix the relative position of each of the N movable parts with respect to the base in the extension and retraction direction.

3. The floating unit according to claim 1 or 2, wherein each of the N load sensors is positioned on the side of the second connecting portion rather than the center portion in the extension and retraction direction of the movable portion.

4. The floating unit according to any one of claims 1 to 3, wherein each of the N telescopic cylinders is an electric cylinder.

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