JP6493962B2 - Compliant actuator - Google Patents

Description

  The present invention relates to a compliant actuator that enables flexible driving according to an external force.

  Humanoid robots, care support robots, or surgery support robots that coexist in the human life space drive in consideration of these situations when an unexpected collision or contact with a human occurs during the operation. Compliance performance (flexibility) is required. Conventionally, an actuator to which a servo system is applied is used in order to ensure the compliance performance (for example, see Patent Document 1).

JP 2013-212564 A

  However, in the servo system, due to the complexity of the system and the limit of the frequency response inherent in the controller, the response to sudden shock input is insufficient. Therefore, a new actuator having a flexibility capable of quickly responding to an unexpected external force is required for a robot coexisting with a human.

  The present invention has been devised by paying attention to such inconveniences, and the object thereof is a compliant actuator capable of shortening response time and exhibiting flexibility with a relatively simple configuration. Is to provide.

  In order to achieve the above object, the present invention mainly provides a fluid pressure cylinder that generates a driving force by the pressure of a working fluid in a compliant actuator that enables flexible driving according to an external force, and the fluid pressure cylinder includes the fluid pressure cylinder. Fluid supply means for supplying a working fluid; and control means for controlling the operation of the fluid pressure cylinder and the supply of the working fluid to the fluid pressure cylinder by the fluid supply means. A cylinder tube; and a piston that is movably provided in an internal space of the cylinder tube and that generates the driving force by the movement. The internal space of the cylinder tube is formed by first and second chambers by the piston. Each of these chambers has a magnetic fluid whose viscosity changes according to the strength of the acting magnetic field. The piston is provided as a working fluid, and the piston includes a communication channel that communicates the first and second chambers, and a magnetic field generation unit that generates a magnetic field inside the communication channel, and the fluid supply unit includes The magnetic fluid can be supplied to any one of the first and second chambers, and the control means controls the flow rate of the magnetic fluid supplied into the chambers by the fluid supply means. At the same time, by controlling the magnetic field generated in the communication flow path, the viscosity of the magnetic fluid is changed, and the flow rate of the magnetic fluid passing through the communication flow path is adjusted so that the driving state of the piston is changed. The composition is to change.

  According to the present invention, by controlling the magnetic field in the communication channel, the viscosity of the magnetic fluid in the communication channel can be made variable, and the flow rate of the magnetic fluid flowing between the first and second chambers is adjusted. Can do. In addition, since the supply flow rate of the magnetic fluid to the first or second chamber is also controlled by the fluid supply means, various variations of flexibility can be exhibited in the actuator. At this time, the flow rate of the magnetic fluid flowing between the first and second chambers is controlled by the magnetic field control in the communication flow path, so that it is not necessary to provide many devices such as complicated control circuits, fluid circuits, and valves. The drive flexibility can be exhibited with a relatively simple configuration. In addition, according to the present invention, the change in the viscosity of the magnetic fluid due to the application of a magnetic field is used to change the drive characteristics of the actuator, so that the back drivable performance is improved, the low output inertia, the high operation bandwidth, the torque -The actuator can have various characteristics such as improved mass ratio, shortened response time, and accurate controllability of output torque, making it suitable as an actuator for robots that coexist in human living spaces. .

The schematic block diagram of the compliant actuator which concerns on this embodiment. Sectional drawing of the piston in the direction in alignment with the AA of FIG. The schematic perspective view of MR plug. The schematic perspective view of an electromagnet core.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a compliant actuator (hereinafter simply referred to as “actuator”) according to the present embodiment. In this figure, an actuator 10 is an actuator that enables flexible driving according to an external force, and generates a driving force by the pressure of the working fluid, and supplies the working fluid to the fluid pressure cylinder 11. Fluid supply means 12 for controlling the operation of the fluid pressure cylinder 11 and control means 13 for controlling the supply of the working fluid from the fluid supply means 12 to the fluid pressure cylinder 11.

  As the working fluid, a magnetic fluid (MR fluid) whose viscosity (viscosity) changes according to the strength of the acting magnetic field is used. This magnetic fluid is a kind of functional fluid in which highly concentrated ferromagnetic particles having a surface covered with a surfactant are dispersed in water or oil. The magnetic particles are affected by a magnetic field. It is designed to change the apparent viscosity of the liquid. Although not particularly limited, in this embodiment, as a magnetic fluid, in order to reduce the minimum resistance force in a non-magnetized state, the diameter of the magnetic particles is about 130 nm, and the concentration of the magnetic particles is 15 % Of nano MR fluid is used.

  The fluid pressure cylinder 11 includes a hollow cylinder tube 15, first and second caps 16 and 17 attached so as to close both left and right ends of the cylinder tube 15 in FIG. 1, and an internal space of the cylinder tube 15. 15A is movably disposed, and the piston 19 that generates the driving force by the movement is disposed so as to extend from the piston 19 to the right in FIG. A piston rod 20 is provided that can advance and retreat in and out of the internal space 15A of the tube 19 (left and right direction in FIG. 1).

  The cylinder tube 15 has a cylindrical shape, and its internal space 15A is partitioned by a piston 19 into two spaces located on the left and right sides in FIG. 1, and these two spaces are each filled with a magnetic fluid. First and second chambers 22 and 23 are provided.

  In the first cap 16 located on the left end side in FIG. 1, a first port 25 is formed to be released to the outside from the first chamber 22 located on the left side of the piston 19 in the figure. The first port 25 is connected to the fluid supply means 12, and the magnetic fluid can be supplied to or discharged from the first chamber 22 by the operation of the fluid supply means 12. The first cap 16 is provided with a bleed port 26 for venting air to the outside. The bleed port 26 is formed so as to branch from the middle of the first port 25 and be released to the outside. Yes. When air is not vented, the bleed port 26 is closed by a cap or the like (not shown).

  In the second cap 17 located on the right end side in FIG. 1, a second port 27 is formed to be released from the second chamber 23 located on the right side of the piston 19 in the figure. The second port 27 is also connected to the fluid supply means 12, and the magnetic fluid can be supplied to or discharged from the second chamber 23 by the operation of the fluid supply means 12. Further, the second cap 17 is formed with a through hole 29 penetrating in the left-right direction in the figure, and the distal end side 20A of the piston rod 20 extending from the piston 19 is the right end of the second cap 17 in FIG. Projecting from the outside.

  The piston 19 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the cylinder tube 15, and is arranged so as to be movable in the left-right direction in FIG. Although not shown in the drawing, a sealing material or a ring is interposed between the inner peripheral surface of the cylinder tube 15 and the outer peripheral surface of the piston 19 in order to prevent passage of magnetic fluid therebetween. Has been.

  As shown in FIG. 2, the piston 19 constitutes an outer peripheral portion of the piston 19. The outer housing 31 is formed in a substantially cylindrical shape by a nonmagnetic material, and the inner space of the outer housing 31 is arranged along the circumferential direction. It consists of MR plugs 33 provided at four positions that are spaced apart, electromagnets 34 that are arranged between the MR plugs 33 and that form magnetic field generating means for generating a magnetic field around them, and sensors that are not shown.

  As shown in FIGS. 1 and 2, the MR plug 33 communicates the first and second chambers 22, 23, and a communication flow path 36 serving as a magnetic fluid flow path between the chambers 22, 23. And a plug body 37 that forms the communication flow path 36. In the present embodiment, the MR plugs 33 are provided at four locations. However, the present invention is not limited to this, and the MR plugs 33 may be provided at one or a plurality of locations.

  As shown in FIGS. 2 and 3, the plug main body 37 has an outer shape in which two portions at intervals of 180 degrees in the circumferential direction are cut out into a concave thin shape with respect to the cross-sectional shape of the cylinder. That is, the plug body 37 includes a concave groove 42 that is a thin-walled portion and a circumferential surface portion 43 around the concave groove 42. Here, the forming portion 42A of the concave groove 42 is formed of a magnetic material, while the circumferential surface portion 43 is formed of a nonmagnetic material.

  As shown in FIG. 2, the electromagnet 34 is disposed in the communication flow path 36 so as to generate a magnetic field, and an electromagnet core 45 made of a metal having a high magnetic permeability such as permalloy, and an electromagnet core 45. The coil 46 is wound around.

  As shown in FIG. 4, the electromagnet core 45 is fixed to a magnet main body 48 having a shape substantially corresponding to a part of a cylindrical shape, and both end faces of the magnet main body 48, and is fitted into the concave groove 42 of the plug main body 37. It consists of a plate-like member 49 which is a portion to be attached.

  Although not shown in FIG. 4, the coil 46 is wound around the magnet body 48 in the vertical direction in FIG. 4, and is arranged outside the fluid pressure cylinder 11 and is not shown. External power is supplied from the device. When the coil 46 is energized, a magnetic field is generated inside the communication channel 36.

  The electromagnet 34 having the above-described configuration is mounted between the concave grooves 42 of the four MR plugs 33, and the formation portion 42A of the concave groove 42 is formed of a magnetic material. It is arranged like a toroidal coil across In addition to the arrangement of the electromagnet 34, the outer housing 31 and the circumferential surface portion 43 of the plug body 37 are formed of a non-magnetic material, so that the magnetic field can be efficiently concentrated in the communication flow path 36. become.

  Although not shown, the sensors provided on the piston 19 can detect the position of the piston 19 and a magnetic sensor such as a Hall effect sensor that can detect the magnitude of the magnetic field generated in the communication flow path 36. It consists of a position sensor and the like.

  As shown in FIGS. 1 and 2, the piston rod 20 is fixed to the piston 19 so as not to move relative to the piston 19 while passing through the central portion of the piston 19 that is radially inward of the MR plug 33 and the electromagnet 34. Has been. In addition, a cable housing portion 51 that houses a coil 46 and a cable connected to the sensors is formed inside the piston rod 20. When the piston 19 moves in the internal space 15A of the cylinder tube 15, the piston rod 20 moves so as to advance and retreat in and out of the internal space 15A. As the piston rod 20 moves, a driving force serving as an output of the actuator 10 is applied to a member or the like (not shown) connected to the distal end side 20A. Here, although not shown, a force sensor for detecting an acting external force or the like is provided on the distal end side 20A of the piston rod.

  In the fluid pressure cylinder 11 configured as described above, when a magnetic field is generated in the communication channel 36 by supplying current to the electromagnet 34, the viscosity of the magnetic fluid passing through the communication channel 36 according to the strength thereof. Changes. That is, the stronger the magnetic field, the higher the viscosity of the magnetic fluid and the shear stress increases, and the passage through the communication channel 36 is hindered. Therefore, by adjusting the strength of the magnetic field, the flow rate and flow velocity of the magnetic fluid passing through the communication channel 36 can be adjusted. In particular, a magnetic fluid having a property of preventing the passage of the magnetic fluid in the communication flow path 36 by the viscosity of the magnetic fluid when a magnetic field having a strength exceeding a predetermined value is generated is used. Therefore, when a magnetic field having a strength exceeding a predetermined value is generated, the communication flow path 36 is closed as if it was closed by a valve, and the magnetic fluid between the first and second chambers 22 and 23 is blocked. There is no movement. Note that the strength of the magnetic field at this time is determined by the performance and type of the magnetic fluid. Therefore, the communication flow path 36 can be switched between a released state that allows passage of magnetic fluid and a closed state that disables the passage by magnetic field control, and the flow rate and flow rate of the passing magnetic fluid can be adjusted. It will function as a possible variable flow valve.

  Although not shown in the drawing, the fluid supply means 12 includes pipes connected to the first and second ports 25 and 27 of the fluid pressure cylinder 11, valves appropriately disposed in the middle of the pipes, and pipes. A pump unit for supplying magnetic fluid into the passage, a flow sensor for detecting the flow rate of the magnetic fluid supplied to the fluid pressure cylinder 11, a pressure sensor for detecting the differential pressure between the first and second ports 25 and 27, etc. It is comprised including. The operations of the pump unit and valves are controlled by the control means 13, and when the pump unit is driven based on this control, the magnetic fluid is fluid pressure from either the first or second port 25, 27. It is supplied to one chamber 22, 23 of the cylinder 11, and the magnetic fluid in the other chamber 22, 23 is discharged to the outside of the fluid pressure cylinder 11 through one of the first or second ports 25, 37. Further, when the pump unit is stopped, the magnetic fluid does not flow into the fluid pressure cylinder 11 from the outside.

  In the control means 13, the operation of the pump unit of the fluid supply means 12 is controlled based on the performance and specifications of the actuator required in advance and the detection results from the respective sensors described above, and supplied to the fluid pressure cylinder 11. The flow rate of the magnetic fluid is adjusted. In addition, the control means 13 performs magnetic field control so as to change the strength of the magnetic field generated by the electromagnet 34, and the viscosity and flow rate and flow velocity of the magnetic fluid passing through the communication flow path 36 are changed. Adjusted.

  In the control means 13, the flow rate of the magnetic fluid supplied from the fluid supply means 12 to the fluid pressure cylinder 11 and the adjustment of the supply current to the electromagnet 34 are adjusted according to each mode described in detail below. The magnetic field control is performed. The modes include a passive holding mode, a passive back drive mode, a closed piston mode, an open piston mode, and an extra flow mode. Next, these modes will be described.

1) Passive holding mode In this mode, the piston 19 is held at the same position without supplying the magnetic fluid to the fluid pressure cylinder 11 by the fluid supply means 12. That is, in this mode, the strength of the magnetic field is controlled to a predetermined value by adjusting the current supplied to the electromagnet 34 so that the communication flow path 36 is in a closed state that disables the passage of the magnetic fluid. The piston 19 is held at the same position without supplying magnetic fluid from the outside. In this mode, when an external force acts on the piston rod 20, the first or second chamber 22, 23 is compressed via the piston 19 according to the acting direction, and the compressed-side chambers 22, 23 are compressed. The magnetic fluid present in the gas tends to flow to the opposite chambers 22 and 23 through the communication channel 36. However, the magnetic fluid at this time is in a state where it does not flow through the communication flow path 36 due to an increase in viscosity due to the control of the magnetic field, and the magnetic fluid is not supplied from the outside to the fluid pressure cylinder 11. The second chambers 22 and 23 are in an independent state in which the magnetic fluid does not flow in and out, and the piston 19 is held at the same position. When this mode is selected, the magnetic field control is performed in accordance with the preset external force value or the magnitude of the external force acting on the piston rod 20 detected by the force sensor in consideration of the friction force. Is done. That is, in this mode, the viscosity is adjusted and a supply current to the electromagnet 34 is required so that the minimum viscosity of the magnetic fluid for closing the communication channel 36 against these external forces is obtained. Can be minimal.

  According to this mode, even when an external force such as an impact force suddenly acts on the piston rod 20 which is a transmission portion of the driving force in a state where the driving force of the actuator 10 is not generated, the piston rod 20 is kept at a fixed position. It is possible to avoid a situation such as unexpected operation, and to ensure the safety of human interaction. Further, since the fluid supply means 12 is not operated, the piston rod 20 can be held at a certain position with energy saving.

2) Passive back drive mode In this mode, the magnetic fluid is not supplied to the fluid pressure cylinder 11 by the fluid supply means 12, and the magnetic fluid flows through the communication flow path 36 so that the piston 19 is moved by an external force. Allow. That is, in this mode, a magnetic field is not generated or the current supplied to the electromagnet 34 is adjusted according to the magnitude of the external force so that the communication flow path 36 is in a released state that allows passage of the magnetic fluid. By doing so, the magnetic field is controlled so that the magnetic fluid yields to an external force and has a viscosity that allows the flow. Therefore, in this mode, when an external force acts on the piston rod 20, the first or second chamber 22, 23 is compressed via the piston 19 according to the acting direction, and the compressed chamber 22, 23 is compressed. The magnetic fluid 23 flows into the opposite chambers 22 and 23 through the communication flow path 36, so that the movement of the piston 19 in the acting direction of the external force is allowed.

3) Closed-piston mode In this mode, the magnetic fluid is supplied to the fluid pressure cylinder 11 by the fluid supply means 12, and a magnetic field is generated in the communication flow path 36 in the same manner as in the passive holding mode. 36 is closed, and the magnetic fluid is prevented from moving between the first and second chambers 22 and 23 via the communication channel 36. That is, in this mode, the piston 19 moves in the direction of the other chamber 22 or 23 by supplying the magnetic fluid from the fluid supply means 12 to the first or second chamber 22 or 23. In this mode, the moving speed of the piston 19 is controlled by the control means 13 based on the detection values of the position sensor and the flow rate sensor so that the moving speed of the piston 19 becomes a target speed set in advance according to the purpose of use and the use state. The supply flow rate of the magnetic fluid from the means 12 is controlled. In this mode, the detection values of the force sensor and the magnetic sensor are set so that the driving force transmitted from the piston rod 20 to the outside has a desired magnitude set in advance according to the purpose of use and the state of use. Based on this, the strength of the magnetic field generated in the communication flow path 36 is also controlled by the control means 13. That is, in the strength range of the magnetic field where the flow rate of the magnetic fluid passing through the communication channel 36 becomes zero, the stronger the magnetic field, the greater the shear stress of the magnetic fluid in the communication channel 36, and the fluid supply means 12. The pressure in the pressurizing chambers 22 and 23 to which the magnetic fluid is supplied increases, and the driving force increases.

  According to this mode, the control means 13 controls the supply flow rate of the magnetic fluid from the fluid supply means 12 and the strength of the magnetic field generated in the communication flow path 36, whereby the drive speed and drive of the actuator 10 are controlled. The combination with the force can be freely set. For example, various behaviors of the actuator 10 with variable flexibility can be realized, such as slowly moving the piston rod strongly and conversely, moving the piston rod quickly and softly. When flexibility behavior is required, from the viewpoint of ensuring safety during unexpected contact with the piston rod 20, the magnetism that passes through the communication flow path 36 can be quickly shifted to the open piston mode described later. The minimum magnetic field strength that makes the fluid flow rate zero is good. On the other hand, when the building is demolished, debris removed, metal casting or striking with the actuator 10 as power, that is, the actuator 10 has a hard behavior that can obtain a desired driving force even when subjected to a high impact. When required, the maximum magnetic field strength is preferably set so that the flow rate of the magnetic fluid passing through the communication channel 36 is zero.

4) Open Piston Mode In this mode, the magnetic fluid is supplied to the fluid pressure cylinder 11 by the fluid supply means 12, and the magnetic field in the communication flow path 36 is moved so that the magnetic fluid can move through the communication flow path 36. Strength is controlled. In this mode, an external force in the direction opposite to the direction of the driving force is applied to the piston rod 20 in a state where a desired driving force is output from the piston rod 20 due to the supply of the magnetic fluid from the fluid supply means 12. In this case, the driving force is flexibly changed in consideration of the magnitude of the external force. That is, in this mode, there is a next submode corresponding to the magnitude of the external force. In the sub-mode, active pulling that moves the piston 19 in the direction opposite to the direction in which the driving force is applied, active holding in which the piston 19 is not moved, and movement in the same direction as the direction in which the driving force is applied are performed. It consists of active push. In these sub modes, the flow control from the fluid supply unit 12 and the magnetic field control in the communication flow path 36 are performed based on the detection value of the force sensor or the like that detects an external force in consideration of the frictional force of the piston 19. Done. In the active pull, the driving force is controlled to be smaller than the external force so as to move the piston 19 in the acting direction of the external force. In the active holding, the external force and the driving force are controlled so that the piston 19 does not move. In the active push, the driving force is controlled to be larger than the external force so as to move the piston 19 in the direction opposite to the direction in which the external force acts.

  In this mode, the actuator 10 can generate a flexible driving force in consideration of an external force by the flow rate control supplied from the fluid supply unit 12 and the magnetic field control in the communication flow path 36. For this reason, an impact received from the actuator 10 can be flexibly buffered against the counterpart side to which the driving force is applied from the actuator 10, and for example, it is expected to contribute to ensuring safety in human interaction. .

  In addition, since the movement of the magnetic fluid in the communication flow path 36 is allowed, quick response by magnetic field control is possible without performing devices such as valves and special control methods, and high backdrive performance. Can be demonstrated.

5) Extra flow mode In this mode, as in the open piston mode, the fluid supply means 12 supplies magnetic fluid to the fluid pressure cylinder 11 and allows the magnetic fluid to move through the communication flow path 36. Although the strength of the magnetic field in the flow path 36 is controlled, this mode is control when the same external force as that in the driving direction of the piston rod 20 is applied. In this mode, since the magnetic fluid flows through the communication flow path 36, when the same external force as that in the driving direction of the piston rod 20 is applied, one of the chambers 22, 23 on the rear side in the direction in which the external force is applied. The shortage of the magnetic fluid inside is quickly replenished with the magnetic fluid in the other chambers 22 and 23 on the front side. Therefore, in such a case, it is not necessary to increase the supply flow rate of the magnetic fluid from the outside by the fluid supply means 12, so it is not necessary to power up and operate the fluid supply means 12, and it is possible to save energy and quickly. Is possible.

  Therefore, in the open piston mode and the extra flow mode, it is assumed that an external force is applied to the piston 19 when the piston 19 is driven by the supply of the magnetic fluid from the fluid supply means 12. In such a case, a desired behavior of the actuator 10 in consideration of the external force can be quickly obtained regardless of the magnitude and direction of the external force.

  In each mode described above, a desired mode is automatically or manually selected according to various conditions such as the application, driving state, purpose of use, and connection environment of the actuator 10, and various controls for executing the mode are performed. Is performed by the control means 13. Hereinafter, several setting examples of each mode will be exemplified, but the present invention is not limited to this.

  In the passive holding mode, when an external force of a predetermined value or more is applied, it is possible to adopt a setting in which the communication channel 16 is released by the magnetic field control in the communication channel 16 and the mode is shifted to the passive back drive mode. According to this, an unexpected accident or failure can be quickly avoided.

  Further, in the closed piston mode, when an external force of a predetermined value or more is applied, it is possible to adopt a setting in which the communication flow path 16 is switched to the released state by the magnetic field control in the communication flow path 16 and the operation proceeds to the open piston mode. This also makes it possible to avoid unexpected accidents and breakdowns quickly.

  On the contrary, in the open piston mode, in order to instantaneously obtain a large driving force, it is possible to adopt a setting in which the communication channel 16 is switched to the closed state by the magnetic field control in the communication channel 16 and the closed piston mode is shifted. According to this, it is possible to respond quickly while saving energy, rather than increasing the flow rate of the magnetic fluid supplied from the fluid supply means 12 to the fluid pressure cylinder 11.

  Further, unlike the passive holding mode, the active holding sub-mode is a state in which a driving force is generated from the piston rod 20 and cancels out an external force acting in the opposite direction. For example, when the pressure is changed without changing the object, it is possible to apply the force control to the hard static object.

  In the passive holding mode, when the piston 19 is to be held at the same position even when an external force larger than the assumed external force is applied, the communication channel 16 is switched from the closed state to the released state, and the fluid supply means It is possible to adopt a setting to shift to the active piston sub-mode in the open piston mode in which the magnetic fluid supply from 12 is started.

  Furthermore, when generating a driving force in the actuator 10, in order to ensure safety due to coexistence with a human, the closed piston mode is selected when there is no human, but when there is a human, the open piston mode is selected. The setting to select can be adopted.

  Therefore, according to such an embodiment, a hard state can be obtained in accordance with changes in various situations with respect to the actuator 10 without employing a complicated configuration using devices such as a control system, a fluid conduit configuration, and a valve. Alternatively, it is possible to select a soft state and operate with a driving force and a driving speed of an arbitrary size, or hold a stopped state. For this reason, it is suitable for devices that require flexible driving with respect to external forces, such as humanoid robots, nursing robots, surgical robots, and other human-related robots. Can be expected.

  In addition, since the drive adjustment relating to the flexibility of the actuator 10 is controlled by controlling the strength of the magnetic field generated in the communication flow path 36, it is necessary to provide a special fluid circuit, a complicated control system, and the like separately. In addition, the high response speed by the magnetic field control makes it possible to quickly switch between the modes with a simple configuration. As a result, it is possible to quickly cope with the disturbance generated in the actuator 10.

  Furthermore, in accordance with the required operation of the actuator 10, desired control can be performed in a state where the strength of the magnetic field generated in the communication flow path 36 and the flow rate of the magnetic fluid supplied to the fluid pressure cylinder 11 are minimized. This can be performed, and energy saving during driving of the actuator 19 can be promoted.

  In addition, the configuration of each part of the apparatus in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same operation is achieved.

DESCRIPTION OF SYMBOLS 10 Actuator 11 Fluid pressure cylinder 12 Fluid supply means 13 Control means 15 Cylinder tube 15A Internal space 19 Piston 22 1st chamber 23 2nd chamber 34 Electromagnet (magnetic field generation means)
36 Communication channel

Claims (2)

In a compliant actuator that enables flexible driving according to external force,
A fluid pressure cylinder for generating a driving force by the pressure of the working fluid; fluid supply means for supplying the fluid to the fluid pressure cylinder; operation of the fluid pressure cylinder; and the fluid pressure cylinder to the fluid pressure cylinder by the fluid supply means Control means for controlling the supply of the working fluid,
The fluid pressure cylinder includes a hollow cylinder tube and a piston that is movably provided in an inner space of the cylinder tube and generates the driving force by the movement.
The internal space of the cylinder tube is partitioned into first and second chambers by the piston, and a magnetic fluid whose viscosity changes according to the strength of the acting magnetic field is accommodated as the working fluid in each of the chambers. And
The piston includes a communication channel that communicates the first and second chambers, and a magnetic field generation unit that generates a magnetic field in the communication channel.
The fluid supply means is provided so as to be able to supply the magnetic fluid to any one of the first and second chambers,
The control means controls the flow rate of the magnetic fluid supplied into the chambers by the fluid supply means and controls the magnetic field generated in the communication flow path to be changed. By changing the viscosity of the fluid and performing magnetic field control for adjusting the flow rate of the magnetic fluid passing through the communication flow path in a plurality of patterns, the compliance performance of different variations according to the action state of the external force is achieved. Changing the driving state of the piston,
In the control means, the magnetic fluid can be switched between a closed state in which passage of the communication flow path is disabled and a release state in which the magnetic fluid is allowed to pass through the communication flow path. Perform magnetic field control to adjust the viscosity of the magnetic fluid,
In the control means, a passive holding mode for stopping the supply of the magnetic fluid into the chambers by the fluid supply means in the closed state according to a desired driving state of the piston, and by the fluid supply means A closed piston mode for supplying the magnetic fluid into each chamber is provided to be selectable,
In the passive holding mode, the frictional force is taken into account, and the closed state is set against the external force according to the preset value of the external force or the magnitude of the acting external force transmitted to the piston. The magnetic field control is performed so that the minimum viscosity of the magnetic fluid is obtained,
In the closed piston mode, the flow rate control is performed so that the piston moves at a preset target speed, and the driving force transmitted to the outside by the movement of the piston is set to a predetermined desired magnitude. the features and to Turkey down ply ant actuator that field control is performed so that the. In a compliant actuator that enables flexible driving according to external force,
A fluid pressure cylinder for generating a driving force by the pressure of the working fluid; fluid supply means for supplying the fluid to the fluid pressure cylinder; operation of the fluid pressure cylinder; and the fluid pressure cylinder to the fluid pressure cylinder by the fluid supply means Control means for controlling the supply of the working fluid,
The fluid pressure cylinder includes a hollow cylinder tube and a piston that is movably provided in an inner space of the cylinder tube and generates the driving force by the movement.
The internal space of the cylinder tube is partitioned into first and second chambers by the piston, and a magnetic fluid whose viscosity changes according to the strength of the acting magnetic field is accommodated as the working fluid in each of the chambers. And
The piston includes a communication channel that communicates the first and second chambers, and a magnetic field generation unit that generates a magnetic field in the communication channel.
The fluid supply means is provided so as to be able to supply the magnetic fluid to any one of the first and second chambers,
The control means controls the flow rate of the magnetic fluid supplied into the chambers by the fluid supply means and controls the magnetic field generated in the communication flow path to be changed. By changing the viscosity of the fluid and performing magnetic field control for adjusting the flow rate of the magnetic fluid passing through the communication flow path in a plurality of patterns, the compliance performance of different variations according to the action state of the external force is achieved. Changing the driving state of the piston,
In the control means, the magnetic fluid can be switched between a closed state in which passage of the communication flow path is disabled and a release state in which the magnetic fluid is allowed to pass through the communication flow path. Perform magnetic field control to adjust the viscosity of the magnetic fluid,
In the control means, a passive back drive mode for stopping the supply of the magnetic fluid into the chambers by the fluid supply means in the released state according to a desired drive state of the piston, and the fluid supply means The open piston mode or the extra flow mode for supplying the magnetic fluid into the chambers according to the above can be selected,
In the passive back drive mode, the movement of the piston by an external force is allowed by generating the magnetic field or by controlling the magnetic field according to the magnitude of the external force,
In the open piston mode, when an external force in a direction opposite to the direction in which the driving force acts is applied to the piston, the flow control and the magnetic field control are made so that the driving force can be changed in consideration of the magnitude of the external force. Is done,
In the extra flow mode, when an external force in the same direction as the direction in which the driving force acts is applied to the piston, the shortage of the magnetic fluid in any one of the chambers behind the direction of the action is determined. the other of the to be replenished rapidly in the magnetic fluid in the chamber, wherein the to Turkey down ply ant actuator in that the magnetic field control is performed.

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