JP2013198942A - Control method of link actuation device and its control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method used in a link actuation device which can perform operation in a wide actuation range while being compact in size, and capable of performing accurate positioning operation at a high speed.SOLUTION: A link actuation device 51 is connected to a link hub 2 at a base end side so that a link hub 3 at a tip side can be changed in attitude via three or more sets of link mechanisms 4, and arbitrarily changes an attitude of the link hub 3 at the tip side with respect to the link hub 2 at the base end side by using actuators 53 arranged at the two or more link mechanisms 4. Operation at each actuator 53 is controlled by synchronous control for making all the actuators 53 simultaneously started in operation and simultaneously completed in operation, and there is performed attitude control for changing the link hub 3 at the tip side to an arbitrary attitude. Deceleration times of all the actuators 53 are set in the vicinity of one cycle of a resonance frequency possessed by the link actuation device 51, and the synchronous control and the attitude control are performed.

Description

  The present invention relates to a control method for a link operating device that requires a precise and wide operating range, such as medical equipment and industrial equipment, and a control device therefor.

  An example of a working device having a link mechanism main body is disclosed in Patent Document 1, and an example of a link actuating device used for medical equipment, industrial equipment, and the like is disclosed in Patent Document 2, respectively.

JP 2000-94245 A US Pat. No. 5,893,296

  Since the link mechanism main body of patent document 1 has a small operating angle of each link, in order to set the operating range of a traveling plate large, it is necessary to lengthen a link length. Thereby, there existed a problem that the dimension of the whole mechanism became large and an apparatus became large. Further, when the link length is increased, the rigidity of the entire mechanism is reduced. For this reason, there is a problem that the weight of the tool mounted on the traveling plate, that is, the transportable weight of the traveling plate is limited to a small one. For these reasons, it is difficult to use in a medical device or the like that requires a precise and wide range of operation while having a compact configuration.

  The link actuating device of Patent Document 2 has a configuration in which three or more three-link linkage mechanisms are provided, so that it can operate in a precise and wide range of operation while having a compact configuration. However, the link actuating device having this configuration changes the position and posture of the distal end member relative to the proximal end member via the link mechanism. There is a problem that the settling time, which is the time until the positioning of the distal end side member is completed, becomes long due to the rigidity.

An object of the present invention is a control that can be applied to a link actuator capable of operating in a wide operating range while having a compact configuration, and can realize a high-speed and high-precision positioning operation of a tip side member. Is to provide a method.
Another object of the present invention is to control a link operating device that can operate in a wide operating range and achieve a high-speed and high-accuracy positioning operation of a tip side member while having a compact configuration. Is to provide a device.

In the link actuator control method according to the present invention, the link hub on the distal end side is connected to the link hub on the proximal end side so that the posture can be changed via three or more sets of link mechanisms. The proximal end and distal end end link members, one end of which is rotatably connected to the proximal end link hub and the distal end link hub, and the other ends of the proximal end and distal end end link members And each link mechanism has a geometric model expressing the link mechanism as a straight line, a proximal end portion and a distal end with respect to a central portion of the central link member. An act of having a shape symmetrical to the side portion, and allowing two or more of the three or more sets of link mechanisms to arbitrarily change the attitude of the distal end side link hub relative to the proximal end side link hub In link actuator provided with a mediator, a method of controlling the operation of the actuator.
In this control method, the operation of each actuator is controlled by synchronous control in which all of the actuators start operation at the same time and the operation is completed at the same time, and the link hub on the distal end side is in an arbitrary posture. The posture control to be changed is performed, and the synchronization control and the posture control are performed by setting the deceleration time of all the actuators in the vicinity of one cycle of the resonance frequency of the link actuator. In addition, the resonance frequency said here is a resonance frequency in the state which installed the object in the link hub of the front end side.

  By performing simultaneous control, all actuators complete their operations at the same time, so the balance of the forces acting on the link hub on the tip side from each link mechanism at the completion of the operation is improved, and the settling time of the link hub on the tip side is improved. Shorter. The settling time is the time from the completion of the operation of the actuator until the link hub on the distal end side completely stops.

  Furthermore, since the link hub on the tip side vibrates in a direction that cancels acceleration after about half a cycle of the resonance frequency, if the deceleration time of the actuator is set near one cycle of the resonance frequency of the link actuator, When performing step acceleration to accelerate, the vibration of the link hub on the tip side after step acceleration is reduced. As a result, the vibration of the link hub on the distal end side after the operation of the actuator is reduced even at high speed operation, and the link hub on the distal end side can be positioned at high speed and with high accuracy. Note that the positioning operation has the same meaning as the posture changing operation because the position of the link hub on the distal end side with respect to the link hub on the proximal end side changes at the same time.

The deceleration time is preferably set within a range of 0.8 to 1.2 periods of the resonance frequency of the link actuator.
The maximum amplitude of the sine wave is 0.75 period and 1.25 period. Therefore, in order to avoid a state of oscillating with the maximum amplitude after completion of deceleration, the deceleration time is set to 0.8 to 1.2 periods of the resonance frequency of the link actuator.

In the present invention, the synchronization control and the attitude control may be performed by setting the acceleration time of all the actuators in the vicinity of one cycle of the resonance frequency of the link actuator.
The link hub on the tip side vibrates in a direction that cancels acceleration after about half a cycle of the resonance frequency. Therefore, if the acceleration time of the actuator is set near one cycle of the resonance frequency of the link actuator, the link hub accelerates periodically. When performing step acceleration, vibration of the link hub on the tip side after step acceleration is reduced. As a result, the vibration of the link hub on the distal end side that occurs at the time of starting is reduced, and the link hub on the distal end side can be positioned at high speed and with high accuracy.

The acceleration time is preferably set within a range of 0.8 to 1.2 periods of the resonance frequency of the link actuator.
The maximum amplitude of the sine wave is 0.75 period and 1.25 period. Therefore, in order to avoid a state of oscillating at the maximum amplitude after completion of acceleration, the acceleration time is set to 0.8 to 1.2 periods of the resonance frequency of the link actuator.

In the present invention, the attitude control determines a command operation amount for each actuator from a target attitude of the link hub on the distal end side, and the synchronous control determines each actuator according to a ratio of the command operation amounts of all the actuators. It is good to set the operation speed.
At the time of controlling the attitude of the link actuator, the command operation amount of each actuator is different. Therefore, if the command speed is set according to the ratio, synchronous control can be easily performed.

The command operation amount of each actuator can be obtained as follows. That is, the rotation angle of the end link member on the base end side with respect to the link hub on the base end side is βn, the connecting end shaft of the central link member rotatably connected to the end link member on the base end side, The angle formed by the connecting end shaft of the central link member rotatably connected to the end link member on the front end side is γ, and the end link members on the base end side with respect to the reference end link member on the base end side Is the vertical angle at which the central axis of the link hub on the distal end side is inclined with respect to the central axis of the link hub on the proximal end side, and θ is the central axis of the link hub on the proximal end side. When the horizontal angle at which the central axis of the link hub on the tip side is inclined is φ,
cos (θ / 2) sinβn−sin (θ / 2) sin (φ + δn) cosβn + sin (γ / 2) = 0
The target rotation angle of each base end side end link member in the posture control is obtained by inversely transforming the expression represented by the formula, and the target rotation angle and each base end side end are obtained. The command operation amount of each actuator is calculated based on a difference from the current rotation angle of the partial link member.
According to this method, the command operation amount can be easily obtained, and posture control is simplified.

Further, the command operation amount of each actuator may be obtained as follows. That is, the rotation angle of the end link member on the base end side with respect to the link hub on the base end side is βn, the connecting end shaft of the central link member rotatably connected to the end link member on the base end side, The angle formed by the connecting end shaft of the central link member rotatably connected to the end link member on the front end side is γ, and the end link members on the base end side with respect to the reference end link member on the base end side Is the vertical angle at which the central axis of the link hub on the distal end side is inclined with respect to the central axis of the link hub on the proximal end side, and θ is the central axis of the link hub on the proximal end side. When the horizontal angle at which the central axis of the link hub on the tip side is inclined is φ,
cos (θ / 2) sinβn−sin (θ / 2) sin (φ + δn) cosβn + sin (γ / 2) = 0
A table showing the relationship between the posture of the distal end side link hub with respect to the proximal end side link hub and the rotation angle of the end link member on each proximal end side by inversely transforming the expression expressed by The target rotation angle of each base end side end link member in the posture control is obtained using this table, and the target rotation angle and each base end side end link member are obtained. The command operation amount of each actuator is calculated based on the difference from the current rotation angle.
According to this technique, the above formula was used by preliminarily tabulating the relationship between the attitude of the distal-side link hub with respect to the proximal-side link hub and the rotation angle of each proximal-side end link member. The calculation time of the command operation amount can be shortened, and the posture control can be performed at higher speed.

で表される式を用いて計算すると良い。
上記式を用いることで、ベース速度Ｖは各アクチュエータの動作速度Ｖｎの合成速度となり、どのような状況においても基端側のリンクハブの移動速度がほぼ一定となるように制御できる。 The operating speed of each actuator is Vn, the base speed is V, the current rotation angle of the end link member on the base end side is βn, and the end link member on the base end side in the posture control is When the target rotation angle is βn ′,

It is good to calculate using the formula represented by.
By using the above formula, the base speed V becomes the combined speed of the operating speed Vn of each actuator, and can be controlled so that the moving speed of the link hub on the base end side is almost constant in any situation.

The operating speed of each actuator is Vn, the maximum speed is Vmax, the current rotation angle of the end link member on the base end side is βn, and the end link on the base end side in the posture control When the target rotation angle of the member is βn ′ and the maximum value of (βn′−βn) is Δβmax,
Vn = Vmax (βn′−βn) / Δβmax
You may calculate using the formula represented by these.
In this case, at least one actuator can always be positioned and driven at the maximum speed, and the movement speed of the link hub on the base end side can be controlled to be maximum.

In this invention, it is preferable that all of the three or more sets of link mechanisms are provided with actuators for arbitrarily changing the attitude of the distal end side link hub with respect to the proximal end side link hub, and these actuators are controlled by redundant control. .
By performing redundancy control, the driving balance of each actuator can be improved regardless of the posture of the link hub on the distal end side, and the settling time of the link hub on the distal end side can be shortened. Furthermore, since it is possible to control the backlash of the actuator and its peripheral part and the backlash of the link mechanism, the vibration of the link hub on the tip side due to the backlash after stopping the actuator can be suppressed, and the settling time is shortened.

In this invention, a resonance frequency detection sensor for detecting the resonance frequency of the link actuator is installed in the link hub on the distal end side, and the resonance frequency is calculated from the signal by a resonance frequency measuring device. It is recommended to update the set values of acceleration time and deceleration time of the actuator.
Even if the tip load or the rigidity of the link actuator changes, the acceleration time and deceleration time can be easily updated, so the vibration of the link hub on the tip side after stopping the actuator is reduced in any situation and at high speed. High-precision positioning operation is possible.

An acceleration pickup may be used as the resonance frequency detection sensor, and an FFT analyzer may be used as the resonance frequency measuring device.
The acceleration pickup is small and easy to install, and the FFT analyzer can easily set the acceleration time and deceleration time.

  The control device for the link actuating device according to the present invention connects the link hub on the distal end side to the link hub on the proximal end side so that the posture can be changed via three or more sets of link mechanisms, The proximal end and distal end end link members, one end of which is rotatably connected to the proximal end link hub and the distal end link hub, and the other ends of the proximal end and distal end end link members And each link mechanism has a geometric model expressing the link mechanism as a straight line, a proximal end portion and a distal end with respect to a central portion of the central link member. An act of having a shape symmetrical to the side portion, and allowing two or more of the three or more sets of link mechanisms to arbitrarily change the attitude of the distal end side link hub relative to the proximal end side link hub An apparatus for controlling the operation of the actuator in a link actuator provided with an eta, and the operation for each actuator by synchronous control for controlling all of the actuators to start and complete simultaneously. And controlling the position of the link hub on the distal end side to an arbitrary position, setting the deceleration time of all the actuators to around one cycle of the resonance frequency of the link actuator, A synchronization / attitude control means for performing synchronization control and attitude control is provided.

  By performing simultaneous control, all actuators complete their operations at the same time, so the balance of the forces acting on the link hub on the tip side from each link mechanism at the completion of the operation is improved, and the settling time of the link hub on the tip side is improved. Shorter.

  Furthermore, since the link hub on the tip side vibrates in a direction that cancels acceleration after about half a cycle of the resonance frequency, if the deceleration time of the actuator is set near one cycle of the resonance frequency of the link actuator, When performing step acceleration to accelerate, the vibration of the link hub on the tip side after step acceleration is reduced. As a result, the vibration of the link hub on the distal end side after the operation of the actuator is reduced even at high speed operation, and the link hub on the distal end side can be positioned at high speed and with high accuracy.

  In the link actuator control method according to the present invention, the link hub on the distal end side is connected to the link hub on the proximal end side so that the posture can be changed via three or more sets of link mechanisms. The proximal end and distal end end link members, one end of which is rotatably connected to the proximal end link hub and the distal end link hub, and the other ends of the proximal end and distal end end link members And each link mechanism has a geometric model expressing the link mechanism as a straight line, a proximal end portion and a distal end with respect to a central portion of the central link member. An act of having a shape symmetrical to the side portion, and allowing two or more of the three or more sets of link mechanisms to arbitrarily change the attitude of the distal end side link hub relative to the proximal end side link hub A method for controlling the operation of the actuator in a link actuating device provided with an etater, the operation for each actuator being performed by synchronous control for controlling all of the actuators to start and complete simultaneously. And controlling the position of the link hub on the distal end side to an arbitrary position, setting the deceleration time of all the actuators to around one cycle of the resonance frequency of the link actuator, Because it performs synchronous control and attitude control, it can be applied to a link actuator that can operate in a wide range of operation while having a compact configuration, and at the high speed of the link hub on the tip side that is the tip side member. A highly accurate positioning operation can be realized.

  The control device for the link actuating device according to the present invention connects the link hub on the distal end side to the link hub on the proximal end side so that the posture can be changed via three or more sets of link mechanisms, The proximal end and distal end end link members, one end of which is rotatably connected to the proximal end link hub and the distal end link hub, and the other ends of the proximal end and distal end end link members And each link mechanism has a geometric model expressing the link mechanism as a straight line, a proximal end portion and a distal end with respect to a central portion of the central link member. An act of having a shape symmetrical to the side portion, and allowing two or more of the three or more sets of link mechanisms to arbitrarily change the attitude of the distal end side link hub relative to the proximal end side link hub An apparatus for controlling the operation of the actuator in a link actuator provided with an eta, and the operation for each actuator by synchronous control for controlling all of the actuators to start and complete simultaneously. And controlling the position of the link hub on the distal end side to an arbitrary position, setting the deceleration time of all the actuators to around one cycle of the resonance frequency of the link actuator, Synchronous and attitude control means for performing synchronization control and attitude control are provided, so that it can operate in a wide range of operation while having a compact configuration, and high speed and high accuracy of the link hub on the tip side, which is the tip side member. Positioning operation can be realized.

It is the front view which abbreviate | omitted a part of one Embodiment of the link actuator with which the control method of this invention is applied. It is the front view which abbreviate | omitted a part which shows one state of the link mechanism main body of the link actuating device. It is the front view which abbreviate | omitted one part which shows the different state of the link mechanism main body of the same link actuator. It is the perspective view which represented the link mechanism main body of the link actuating device three-dimensionally. It is the figure which expressed one link mechanism of the link actuating device with a straight line. It is a fragmentary sectional view of the link mechanism main part of the link actuator. It is a figure which shows the rotation angle of the edge part link member of the base end side of the same link action | operation apparatus. It is a graph which shows the relationship between time and speed of a control parameter. It is a graph which shows the relationship between the acceleration / deceleration when the acceleration / deceleration time is constant and the settling time. It is a graph which shows the relationship between settling time and acceleration / deceleration when a command speed is constant. It is a figure which shows the relationship between the acceleration / deceleration time and settling time in case command speed is constant. It is a graph which shows the amplitude of vibration of the link hub of the tip side at the time of applying step acceleration for one period of resonance frequency. It is the front view which abbreviate | omitted a part of other embodiment of the link actuator with which the control method of this invention is applied. It is a fragmentary sectional view of the link mechanism main part of the link actuator. It is the elements on larger scale of FIG. It is the front view which abbreviate | omitted a part of example of the link actuator to which the other control method of this invention is applied.

  An embodiment of a link actuator to which a control method according to the present invention is applied will be described with reference to FIGS. As shown in FIG. 1, the link actuating device 51 includes a link mechanism main body 1, a base 52 that supports the link mechanism main body 1, and a plurality (the same number as the link mechanism 4 described later) that actuates the link mechanism main body 1. Actuators 53 and a control device 58 for controlling the actuators 53 are provided. In this example, the control device 58 is provided in the controller 54, but the control device 58 may be provided separately from the controller 54.

  The link mechanism main body 1 will be described. 2 and 3 are front views showing different states of the link mechanism main body 1. The link mechanism main body 1 has three sets of link mechanisms 4 in which the link hub 3 on the distal end side is linked to the link hub 2 on the proximal end side. It is connected so that the posture can be changed via. 2 and 3, only one set of link mechanisms 4 is shown.

  FIG. 4 is a perspective view showing the link mechanism body 1 three-dimensionally. Each link mechanism 4 includes a base end side end link member 5, a front end side end link member 6, and a central link member 7, and forms a three-joint link mechanism including four rotating pairs. The end link members 5 and 6 on the base end side and the front end side are L-shaped, and the base ends are rotatably connected to the link hub 2 on the base end side and the link hub 3 on the front end side, respectively. The central link member 7 is rotatably connected to the distal ends of the end link members 5 and 6 on the proximal end side and the distal end side at both ends.

  The end link members 5 and 6 on the base end side and the front end side have a spherical link structure, and the spherical link centers PA and PB (FIGS. 2 and 3) in the three sets of link mechanisms 4 coincide with each other, and the spherical surfaces thereof The distance D from the link centers PA and PB is the same. The central axis of each rotational pair of the end link members 5 and 6 and the central link member 7 may have a certain crossing angle or may be parallel.

  That is, the three sets of link mechanisms 4 have the same geometric shape. The geometrically identical shape is a geometric model in which the link members 5, 6, and 7 are expressed by straight lines, that is, a model that is expressed by each rotation pair and a straight line connecting these rotation pairs. The base end side part and the front end side part with respect to the center part of the are said to have a symmetrical shape. FIG. 5 is a diagram representing a set of link mechanisms 4 in a straight line.

  The link mechanism 4 of this embodiment is a rotationally symmetric type, and the positions of the proximal-side link hub 2 and the proximal-side end link member 5, the distal-side link hub 3 and the distal-side end link member 6. The relationship is a position configuration that is rotationally symmetric with respect to the center line C of the central link member 7. 2 shows a state where the central axis QA of the link hub 2 on the proximal end side and the central axis QB of the link hub 3 on the distal end side are on the same line, and FIG. 3 shows the central axis of the link hub 2 on the proximal end side. A state in which the central axis QB of the link hub 3 on the distal end side takes a predetermined operating angle with respect to QA is shown. Even if the posture of each link mechanism 4 changes, the distance D between the spherical link centers PA and PB on the proximal end side and the distal end side does not change.

  The link hub 2 on the proximal end side, the link hub 3 on the distal end side, and the three link mechanisms 4 allow the distal link hub 3 to move in the two orthogonal directions relative to the link hub 2 on the proximal end side. A degree mechanism is configured. In other words, it is a mechanism that can freely change the posture of the link hub 3 on the distal end side with respect to the link hub 2 on the proximal end side with two degrees of freedom of rotation. Although this two-degree-of-freedom mechanism is compact, the movable range of the link hub 3 on the distal end side with respect to the link hub 2 on the proximal end side can be widened. For example, the maximum value (maximum folding angle) of the bending angle θ between the central axis QA of the link hub 2 on the proximal end side and the central axis QB of the link hub 3 on the distal end side can be set to about ± 90 °. Further, the turning angle φ of the distal end side link hub 3 with respect to the proximal end side link hub 2 can be set in a range of 0 ° to 360 °. The bending angle θ is a vertical angle in which the central axis QB of the distal end side link hub 3 is inclined with respect to the central axis QA of the proximal end side link hub 2, and the turning angle φ is the proximal end side link hub. This is a horizontal angle at which the central axis QB of the link hub 3 on the distal end side is inclined with respect to the central axis QA of the second axis.

  In this link mechanism body 1, the angle and length of the shaft member 13 (FIG. 6) of the end link members 5 and 6 of each link mechanism 4 are equal, and the end link member 5 on the proximal end side and the distal end side link member 5 are on the distal end side. When the geometrical shape of the end link member 6 is equal and the shape of the central link member 7 is the same at the proximal end side, the central link member 7 and the end of the central link member 7 are symmetrical with respect to the symmetry plane of the central link member 7. If the angular positional relationship with the base link members 5 and 6 is the same between the base end side and the tip end side, the base end side link hub 2 and the base end side end link member 5 from the geometric symmetry, The distal end side link hub 3 and the distal end side end link member 6 move in the same manner. For example, when the rotation hubs are provided coaxially with the center axes QA and QB on the link hubs 2 and 3 on the proximal end side and the distal end side, and rotation is transmitted from the proximal end side to the distal end side, the proximal end side and the distal end side are It becomes a constant velocity universal joint that rotates at the same speed at the same rotation angle. The plane of symmetry of the central link member 7 when rotating at a constant speed is referred to as a uniform speed bisector.

  Therefore, by arranging a plurality of link mechanisms 4 having the same geometric shape sharing the base side link hub 2 and the tip side link hub 3 on the circumference, the plurality of link mechanisms 4 can move without contradiction. The central link member 7 is limited to movement only on the equal speed bisector. Thereby, even if the proximal end side and the distal end side have arbitrary operating angles, the proximal end side and the distal end side rotate at a constant speed.

  The link hub 2 on the base end side and the link hub 3 on the front end side have a donut shape in which a through hole 10 is formed in the center portion along the axial direction and the outer shape is a spherical shape. The center of the through hole 10 coincides with the central axes QA and QB of the link hubs 2 and 3. The proximal end link member 5 and the distal end link member 6 rotate at equal intervals in the circumferential direction of the outer peripheral surface of the proximal link hub 2 and distal link hub 3 respectively. It is connected freely.

  FIG. 6 is a cross-sectional view showing a rotational pair of the proximal-side link hub 2 and the proximal-side end link member 5 and a rotational end of the proximal-side end link member 5 and the central link member 7. In the link hub 2 on the base end side, radial communication holes 11 that communicate the axial through hole 10 and the outer peripheral side are formed at three locations in the circumferential direction, and two bearings provided in each communication hole 11. 12, shaft members 13 are rotatably supported. The outer end of the shaft member 13 protrudes from the link hub 2 on the base end side, and the end link member 5 on the base end side is coupled to the protruding screw portion 13 a and is fastened and fixed by a nut 14.

  The bearing 12 is a rolling bearing such as a deep groove ball bearing, for example, and an outer ring (not shown) is fitted to the inner circumference of the communication hole 11, and an inner ring (not shown) is the outer circumference of the shaft member 13. Is fitted. The outer ring is retained by a retaining ring 15. Further, a spacer 16 is interposed between the inner ring and the end link member 5 on the base end side, and the tightening force of the nut 14 is transmitted to the inner ring via the end link member 5 and the spacer 16 on the base end side. Thus, a predetermined preload is applied to the bearing 12.

  The rotating pair of the end link member 5 and the center link member 7 on the base end side is provided with two bearings 19 in communication holes 18 formed at both ends of the center link member 7. A shaft portion 20 at the tip of the end link member 5 is rotatably supported. The bearing 19 is fastened and fixed by a nut 22 via a spacer 21.

  The bearing 19 is a rolling bearing such as a deep groove ball bearing, for example, and an outer ring (not shown) is fitted to the inner circumference of the communication hole 18, and an inner ring (not shown) is the outer circumference of the shaft portion 20. Is fitted. The outer ring is retained by a retaining ring 23. A tightening force of the nut 22 screwed to the tip screw portion 20a of the shaft portion 20 is transmitted to the inner ring through the spacer 21 to apply a predetermined preload to the bearing 19.

  The rotation pair of the base end side link hub 2 and the base end side end link member 5 and the base end side end link member 5 and the central link member 7 have been described above. The rotation pair of the hub 3 and the end link member 6 on the front end side and the rotation pair of the end link member 6 and the center link member 7 on the front end side have the same configuration (not shown).

  Thus, the four rotation pairs in each link mechanism 4, that is, the rotation pair of the link hub 2 on the proximal end side and the end link member 5 on the proximal end side, the link hub 3 on the distal end side and the end link on the distal end side Bearings 12 and 19 are provided on the rotational pair of the member 6, the end link member 5 and the central link member 7 on the base end side, and the rotational pair of the end link member 6 and the central link member 7 on the distal end side. By adopting the structure, it is possible to reduce the rotational resistance by suppressing the frictional resistance at each rotational pair, and to ensure smooth power transmission and improve the durability.

  In the structure in which the bearings 12 and 19 are provided, by applying a preload to the bearings 12 and 19, the radial gap and the thrust gap can be eliminated, and shakiness of the rotation pair can be suppressed. The rotational phase difference between the link hub 3 side on the side and the distal end side is eliminated, and the constant velocity can be maintained and the occurrence of vibration and abnormal noise can be suppressed. In particular, by setting the bearing clearance between the bearings 12 and 19 to be a negative clearance, backlash generated between input and output can be reduced.

  By providing the bearing 12 embedded in the link hub 2 on the proximal end side and the link hub 3 on the distal end side, the outer shape of the entire link mechanism body 1 is not increased, and the link hub 2 on the proximal end side and the distal end side link hub 2 are The outer shape of the link hub 3 can be enlarged. Therefore, it is easy to secure a mounting space for mounting the proximal-side link hub 2 and the distal-side link hub 3 to other members.

  In FIG. 1, a base 52 is a vertically long member, and a link hub 2 on the base end side of the link mechanism main body 1 is fixed to an upper surface thereof. A collar-shaped actuator mounting base 55 is provided on the outer periphery of the upper part of the base 52, and the actuator 53 is mounted on the actuator mounting base 55 in a suspended state. The number of actuators 53 is three, which is the same number as the link mechanism 4. The actuator 53 is a rotary actuator, and a bevel gear 56 attached to the output shaft of the actuator 53 and a fan-shaped bevel gear 57 attached to the shaft member 13 (FIG. 6) of the link hub 2 on the proximal end side mesh with each other.

  The link actuating device 51 operates the link mechanism main body 1 by operating the controller 54 to rotationally drive each actuator 53. Specifically, when the actuator 53 is driven to rotate, the rotation is transmitted to the shaft member 13 via a pair of bevel gears 56 and 57, and the angle of the end link member 5 on the base end side with respect to the link hub 2 on the base end side. Will change. As a result, the position and posture of the distal end side link hub 3 with respect to the proximal end side link hub 2 (hereinafter referred to as “front end position and posture”) are determined. Here, the angle of the end link member 5 on the base end side is changed using the bevel gears 56 and 57, but other mechanisms (for example, a spur gear or a worm mechanism) may be used.

  The rotation of the actuator 53 for operating the link mechanism body 1 is performed by automatic control by the control device 58 based on a command from a command operating device (not shown) provided in the controller 54. The control device 58 is of a numerical control type by a computer and has synchronization / attitude control means 58a. The synchronization / attitude control means 58a controls the synchronization of the three actuators 53 so that all of the three actuators 53 start simultaneously and complete the operation at the same time, and controls the operation of each actuator 53. Attitude control to change 3 to an arbitrary attitude is performed.

  Attitude control is performed as follows. First, the rotation angle βn (FIG. 7) of each end link member 5 on the base end side is determined according to the commanded tip position and orientation. The rotation angle βn referred to here is the rotation angle (angle from the horizontal plane) of each proximal-side end link member 5 corresponding to the commanded tip position and orientation.

The rotation angle βn is obtained, for example, by inversely transforming the following Equation 1. Inverse conversion refers to the bending angle θ (FIG. 4) between the center axis QA of the link hub 2 on the proximal end side and the center axis QB of the link hub 3 on the distal end side, and the link hub on the output side with respect to the link hub 2 on the proximal end side. 3 is a conversion for calculating the rotation angle βn of the end link member 5 on the base end side from the swivel angle φ of FIG. 3 (FIG. 4). The bending angle θ, the turning angle φ, and the rotation angle βn are mutually related, and the other value can be derived from one value.
cos (θ / 2) sinβn−sin (θ / 2) sin (φ + δn) cosβn + sin (γ / 2) = 0
(N = 1, 2, 3) (Formula 1)
Here, γ (FIG. 4) is rotatably connected to the connecting end shaft of the central link member 7 rotatably connected to the end link member 5 on the base end side and the end link member 6 on the tip end side. The angle formed by the connecting end axis of the central link member 7. δn (δ1, δ2, δ3 in FIG. 4) is a circumferential separation angle of each base end side end link member 5 with respect to the base end side end link member 5 serving as a reference.

The rotation angle βn may be obtained by inversely transforming Equation 1 for each command, but a table showing the relationship between the tip position / posture and the rotation angle βn as shown in Table 1 may be created in advance. In the case of a table, if there is a tip position / orientation command, the rotation angle βn can be obtained immediately using the table. Therefore, it is possible to perform posture control at higher speed.

When the rotation angle βn (β1, β2, β3) is obtained, the control parameter is determined for each actuator 53 (53 ₁ , 53 ₂ , 53 ₃ ). The control parameters of the actuators 53 (53 ₁ , 53 ₂ , 53 ₃ ) have waveforms as shown in FIG. 8, for example. That is, the vehicle accelerates from the start of rotation to t1 and maintains the command speed Vn (V1, V2, V3) from t1 to t2, and then decelerates and stops rotating at t3. When the actuator 53 _1, showing the area of the range indicated by hatching, the operation amount of the actuator 53 _1, that is, the rotation angle β1 of the end link member 5 of the base end side. The same applies to the other actuators 53 ₂ and 53 ₃ . As is apparent from the figure, by the synchronous control, the respective actuators 53 (53 ₁ , 53 ₂ , 53 ₃ ) start to operate simultaneously and complete the simultaneous operation, and the acceleration time and the deceleration time also correspond to each actuator 53 (53 ₁ , 53 ₂ , 53 ₃ ).

…（式２）
この場合、ベース速度Ｖは各アクチュエータ５３の指令速度Ｖｎの合成速度となり、どのような状況においても基端側のリンクハブ５の移動速度がほぼ一定となるように制御できる。 For example, the command speed Vn (V1, V2, V3) is a ratio of the difference between the current rotation angle βn (β1, β2, β3) and the command posture rotation angle βn ′ (β1 ′, β2 ′, β3 ′). If the base speed that serves as a reference for the command speed Vn is V, the command speed Vn is expressed by Equation 2.

... (Formula 2)
In this case, the base speed V is a combined speed of the command speed Vn of each actuator 53, and can be controlled so that the moving speed of the link hub 5 on the base end side is almost constant in any situation.

Further, the command speed Vn is a relational expression expressed by Expression 3 when the maximum speed is Vmax and the maximum difference (βn′−βn) between the current rotation angle βn and the rotation angle βn ′ of the command posture is Δβmax. You may calculate using.
Vn = Vmax (βn′−βn) / Δβmax; (n = 1, 2, 3) (Formula 3)
In this case, at least one actuator 53 can always be driven at the maximum speed, and the rotation speed of the link member 5 on the base end side can be controlled to be maximum.

  By setting the command speed Vn of the three actuators 53 in this way, the synchronous control of the three actuators 53 becomes possible. The base speed V and the maximum speed Vmax may be adjusted by the settling time of the link hub 3 on the distal end side. The settling time is the time from the completion of the operation of the actuator 53 until the distal end side link hub 3 completely stops. The acceleration from when the actuator 53 starts to rotate until it reaches the command speed Vn and the deceleration from the command speed Vn until it stops rotating are represented by the slope of the straight line in FIG. 8, and the acceleration time and the command speed Vn, In addition, the speed is determined by the deceleration time and the command speed Vn.

  The acceleration time and deceleration time (referred to as “acceleration / deceleration time”) of each actuator 53 is set in the vicinity of one cycle of the resonance frequency of the link actuator 1. Specifically, it is desirable to set within the range of 0.8 to 1.2 periods of the resonance frequency of the link actuator 1. The reason will be described below. In addition, the resonance frequency said here is a resonance frequency in the state which installed the mounted object in the link hub 3 of the front end side.

  FIG. 9 is a graph showing the relationship between the acceleration / deceleration and the settling time when the acceleration / deceleration time is fixed and the acceleration / deceleration is changed by the base speed V (or command speed Vn). FIG. 10 is a graph showing the relationship between acceleration / deceleration and settling time when the base speed V (or command speed Vn) is constant and the acceleration / deceleration is changed by the acceleration / deceleration time. As shown in FIG. 9, the smaller the acceleration / deceleration, the shorter the settling time is. In FIG. 10, the settling time becomes shorter until a certain acceleration / deceleration, and then the settling time tends to be constant or longer. It is done. As shown in FIG. 11, the inflection point where the tendency of settling time changes can be seen in the vicinity of one cycle of the resonance frequency of the link actuator 1.

  FIG. 12 shows the amplitude of vibration of the link hub 3 on the distal end side when performing step acceleration that accelerates every one period of the resonance frequency. The link hub 3 on the distal end side vibrates in a direction to cancel the acceleration after a half cycle, so that it is considered that the vibration of the link hub 3 on the distal end side after the step acceleration is reduced. Therefore, if the acceleration / deceleration time is set in the vicinity (0.8 to 1.2 cycles), the settling time can be shortened. The sine wave has the maximum amplitude in 0.75 period and 1.25 period. Therefore, in order to avoid a state of oscillating at the maximum amplitude after completion of acceleration or deceleration, the acceleration / deceleration time is set to 0.8 to 1.2 periods of the resonance frequency of the link actuator.

  More preferably, the acceleration / deceleration time may be set within a range of 0.9 to 1.1 periods (± 10%) of the resonance frequency of the link actuator 1. If the acceleration / deceleration time is set within the above range, the amplitude at the end of acceleration / deceleration becomes 1/2 or less with respect to the maximum amplitude of the resonance frequency, and the surplus energy becomes small. As a result, the vibration of the link hub on the tip side after the actuator completes operation even during high-speed operation is reduced, and the link hub on the tip side can be positioned at high speed and with high accuracy, and further settling time can be increased. Shortening is possible.

  The link mechanism main body 1 of the link actuating device 51 is configured to include three sets of three-linkage link mechanisms 4 each including four rotation pairs, and at least two sets of the three sets of link mechanisms 4 are provided with actuators 53. If so, the tip position / posture can be determined. However, in this link actuating device 51, actuators 53 are provided in all three sets of link mechanisms 4, and the rotation of each actuator 53 is controlled by redundant control. Thereby, the balance of the driving torque of each actuator 53 can be improved in any tip position and posture, and the settling time of the link hub 3 on the tip side can be shortened. Further, since it is possible to control the backlash of the actuator 53 and its peripheral portion and the backlash of the link mechanism 4, vibration of the link hub 3 on the tip side due to backlash after the actuator 53 is stopped can be suppressed, and the settling time is shortened. .

  Figures 13 to 15 show different embodiments of the link actuating device. As shown in FIG. 13, the link actuating device 61 can change the posture of a distal end attachment member 63 to which various instruments are attached to the distal end side with respect to the proximal end base 62 via the link mechanism main body 1. It is connected to. A spacer 64 is interposed between the base 62 and the link hub 2 on the base end side of the link mechanism main body 1.

  As shown in FIGS. 14 and 15, the link mechanism body 1 includes bearings 31 that rotatably support the end link members 5 and 6 with respect to the link hub 2 on the proximal end side and the link hub 3 on the distal end side. Outer ring rotation type. The rotation pair of the link hub 2 on the base end side and the end link member 5 on the base end side will be described as an example. Shaft portions 32 are formed at three locations in the circumferential direction of the link hub 2 on the base end side. The inner rings (not shown) of the two bearings 31 are fitted to the outer periphery of the portion 32, and the outer ring (not shown) of the bearing 31 is fitted to the inner periphery of the communication hole 33 formed in the end link member 5 on the proximal end side. Are mated. The bearing 31 is a ball bearing such as a deep groove ball bearing or an angular ball bearing, for example, and is fixed in a state where a predetermined preload is applied by tightening with a nut 34. The rotating pair of the distal end side link hub 3 and the distal end side end link member 6 has the same structure as described above.

  Further, the bearing 36 provided at the rotation pair of the end link member 5 on the base end side and the central link member 7 is connected to the outer ring on the inner periphery of the communication hole 37 formed at the front end of the end link member 5 on the base end side. (Not shown) is fitted, and an inner ring (not shown) is fitted to the outer periphery of the shaft portion 38 integrated with the central link member 7. The bearing 36 is, for example, a ball bearing such as a deep groove ball bearing or an angular ball bearing, and is fixed in a state where a predetermined preload is applied by tightening with a nut 39. The rotational pair of the end link member 6 and the center link member 7 on the front end side has the same structure as described above.

  All of the three sets of link mechanisms 4 of the link mechanism main body 1 have an actuator 70 for arbitrarily changing the distal end position and posture by rotating the end link member 5 on the proximal end side, and the operation amount of this actuator 70 as the proximal end. A speed reduction mechanism 71 that decelerates and transmits to the side end link member 5 is provided. The actuator 70 is a rotary actuator, more specifically a servo motor with a speed reducer 70 a, and is fixed to the base 62 by a motor fixing member 72. The speed reduction mechanism 71 includes a speed reducer 70 a of the actuator 70 and a gear type speed reduction unit 73. In the following, a spur gear is used for the speed reduction mechanism 71, but other mechanisms (for example, a bevel gear or a worm mechanism) may be used.

  The gear type reduction unit 73 is connected to the output shaft 70 b of the actuator 70 through a coupling 75 so as to be able to transmit rotation, and is fixed to the end link member 5 on the proximal end side and is connected to the small gear 76. It is comprised with the large gear 77 which meshes | engages. In the illustrated example, the small gear 76 and the large gear 77 are spur gears, and the large gear 77 is a sector gear in which teeth are formed only on a sector-shaped peripheral surface. The large gear 77 has a larger pitch circle radius than the small gear 76, and the rotation of the output shaft 70 b of the actuator 70 is transferred to the end link member 5 on the base end side, and the link hub 2 on the base end side and the end link on the base end side. It is decelerated and transmitted to the rotation around the rotation axis O1 of the rotation pair with the member 5. The reduction ratio is 10 or more.

  The pitch circle radius of the large gear 77 is set to ½ or more of the arm length L of the end link member 5 on the base end side. The arm length L is determined from the axial center point P1 of the central axis O1 of the rotational pair of the base end side link hub 2 and the base end side end link member 5 to the base end side end link member 5 and the center. An axial center point P1 of the axial center point P2 of the center axis O2 of the rotational pair with the link member 7 is orthogonal to the rotational pair axis O1 of the base end side link hub 2 and the base end side end link member 5. The distance to the point P3 projected on the plane passing through. In the case of this embodiment, the pitch circle radius of the large gear 77 is not less than the arm length L. Therefore, it is advantageous to obtain a high reduction ratio.

  The small gear 76 has shaft portions 76 b projecting on both sides of a tooth portion 76 a meshing with the large gear 77, and both shaft portions 76 b are two bearings provided on a rotation support member 79 installed on the base 62. 80 are rotatably supported by each. The bearing 80 is a ball bearing such as a deep groove ball bearing or an angular ball bearing. In addition to arranging ball bearings in double rows as in the illustrated example, roller bearings or sliding bearings may be used. A shim (not shown) is provided between the outer rings (not shown) of the two bearings 80, and a preload is applied to the bearing 80 by tightening a nut 81 screwed into the shaft portion 76b. The outer ring of the bearing 80 is press-fitted into the rotation support member 79.

  In the case of this embodiment, the large gear 77 is a member separate from the end link member 5 on the base end side, and is detachably attached to the end link member 5 on the base end side by a coupler 82 such as a bolt. ing. The large gear 77 may be integrated with the end link member 5 on the base end side.

  The rotation axis O3 of the actuator 70 and the rotation axis O4 of the small gear 76 are located on the same axis. The rotation axes O3 and O4 are parallel to the rotation pair axis O1 of the base end side link hub 24 and the base end side end link member 5 and have the same height from the base 62.

  The link operating device 61 is also automatically controlled by the control device 85 based on a command from a command operating device (not shown) provided in the controller 84. The control device 85 includes synchronization / attitude control means 85a. With this attitude control means 85a, synchronous control for controlling all the three actuators 70 to start operation at the same time and complete the operation at the same time, and for each actuator 70 The posture control for changing the distal end side link hub 3 to an arbitrary posture is performed. Thereby, the same operation and effect as described above can be obtained.

  This link actuating device 61 can be controlled so that the backlash of the link mechanism main body 1 and the speed reduction mechanism 71 is reduced by providing the actuator 70 and the speed reduction mechanism 71 in all of the three sets of link mechanisms 4. The positioning accuracy of the link hub 3 on the side can be improved, and the link actuator 61 itself can be made highly rigid.

  The gear-type reduction unit 73 of the reduction mechanism 71 is a combination of a small gear 76 and a large gear 77, and a high reduction ratio of 10 or more can be obtained. If the reduction ratio is high, the positioning resolution of the encoder or the like is increased, so that the positioning resolution of the link hub 3 on the distal end side is improved. Also, a low output actuator 70 can be used. In this embodiment, the actuator 70 with the reduction gear 70a is used. However, if the reduction ratio of the gear-type reduction gear 73 is high, the actuator 70 without the reduction gear can be used, and the actuator 70 can be downsized. it can.

By setting the pitch circle radius of the large gear 77 to ½ or more of the arm length L of the end link member 5 on the base end side, the bending moment of the end link member 5 on the base end side due to the tip load is reduced. . Therefore, it is not necessary to increase the rigidity of the entire link operating device 61 more than necessary, and the weight of the end link member 5 on the base end side can be reduced. For example, the end link member 5 on the base end side can be changed from stainless steel (SUS) to aluminum. Further, since the pitch circle radius of the large gear 77 is relatively large, the surface pressure of the tooth portion of the large gear 77 is reduced, and the rigidity of the entire link actuator 61 is increased.
Further, when the pitch circle radius of the large gear 77 is equal to or greater than ½ of the arm length, the large gear 77 is installed on the rotating pair of the base end side link hub 2 and the base end side end link member 5. Since the diameter is sufficiently larger than the outer diameter of the bearing 12, a space is formed between the tooth portion of the large gear 77 and the bearing 12, and the large gear 77 can be easily installed.

  In particular, in the case of this embodiment, the pitch circle radius of the large gear 77 is equal to or greater than the arm length L. Therefore, the pitch circle radius of the large gear 77 is further increased, and the above-described action and effect appear more remarkably. In addition, the small gear 76 can be installed on the outer diameter side of the link mechanism 4. As a result, an installation space for the small gear 76 can be easily secured, and the degree of freedom in design increases. Further, interference between the small gear 76 and other members is less likely to occur, and the movable range of the link actuator 61 is widened.

  Since the small gear 76 and the large gear 77 are spur gears, they are easy to manufacture and have high rotation transmission efficiency. Since the small gear 76 is supported by the bearings 80 on both sides in the axial direction, the support rigidity of the small gear 76 is high. As a result, the angle holding rigidity of the end link member 5 on the proximal end side due to the distal end load is increased, and the rigidity and positioning accuracy of the link actuator 61 are improved. Further, the rotational axis O3 of the actuator 70, the rotational axis O4 of the small gear 76, and the central axis O1 of the rotational pair of the base-side link hub 2 and the base-side end link member 5 are on the same plane. Therefore, the overall balance is good and the assemblability is good.

  Since the large gear 77 is detachable with respect to the end link member 5 on the base end side, the reduction ratio of the gear-type reduction portion 73 and the operation of the link hub 3 on the front end side with respect to the link hub 2 on the base end side. It becomes easy to change the specifications such as the range, and the mass productivity of the link actuating device 61 is improved. In other words, the same link actuating device 61 can be applied to various uses by simply changing the large gear 77. Also, maintainability is good. For example, when a failure occurs in the gear-type reduction unit 73, it is possible to deal with it by replacing only the reduction unit 73.

  FIG. 16 shows a link actuator that controls an actuator by a control method different from the above control method. The link actuating device 91 has the same configuration as that of the link actuating device 61, although the link mechanism main body 1 may have the same configuration as that of the link actuating device 51. This control method can be applied to either case.

  In this control method, a resonance frequency detection sensor 92 that detects the resonance frequency of the link actuator 91 is installed in the link hub 3 on the distal end side. The resonance frequency detection sensor 92 only needs to change its output as the tip position / posture changes, and for example, an acceleration pickup is used. The accelerometer is small and easy to install. In addition, an inclination angle sensor may be used. A resonance frequency measuring device 93 that calculates the resonance frequency from the signal of the resonance frequency detection sensor 92 is installed on the base end side of the link actuator 91. For example, an FFT analyzer is used as the resonance frequency measuring device 93. Acceleration time and deceleration time can be set easily with FFT analyzer. The resonance frequency detecting sensor 92 and the resonance frequency measuring device 93 are connected by a flexible cable 94.

  According to this control method, the resonance frequency measuring device 93 calculates the resonance frequency from the signal of the resonance frequency detection sensor 92, and changes the set value of the acceleration / deceleration time of the actuator (not shown) based on the calculation result. Thereby, even if the tip load or the rigidity of the link actuator 91 changes, the acceleration time and the deceleration time can be easily updated. For example, the acceleration time and the deceleration time can be set optimally even when the load on the link hub 3 on the distal end side is changed or the mounting position is changed. Therefore, in any situation, the vibration of the link hub 3 on the distal end side after the actuator is stopped can be reduced, and high-speed and highly accurate positioning operation can be performed.

  The acceleration time and deceleration time may be updated when the power is turned on, at regular intervals, or artificially at arbitrary timing. Also, during normal operation, the resonance frequency detection sensor 92 always monitors the resonance frequency and automatically sets the acceleration time and deceleration time setting values when there is a deviation compared to the acceleration time and deceleration time setting values. May be updated.

2. Link base 3 on the proximal end side ... Link hub 4 on the distal end side ... Link mechanism 5 ... End link member 6 on the proximal end side ... End link member 7 on the distal end side ... Center link members 51, 61, 91 ... Links Actuating devices 53, 70 ... Actuators 58, 85 ... Control devices 58a, 85a ... Synchronization / attitude control means 92 ... Resonance frequency detection sensor 93 ... Resonance frequency measuring device QA ... Center axis QB of proximal link hub QB ... Tip side Link hub center axis

Claims (13)

The link hub on the distal end side is connected to the link hub on the proximal end side through three or more sets of link mechanisms in such a manner that the posture can be changed, and each of the link mechanisms includes a link hub on the proximal end side and a link hub on the distal end side. End link members on the base end side and the tip end side, one end of which is rotatably connected to the link hub, and a center on which both ends are rotatably connected to the other ends of the end link members on the base end side and the tip end side, respectively. Each of the link mechanisms is a geometric model in which the link mechanism is represented by a straight line, and the base end side portion and the tip end side portion are symmetrical with respect to the center portion of the center link member, In the link operating device, of the three or more sets of link mechanisms, two or more sets of link mechanisms are provided with an actuator for arbitrarily changing the attitude of the distal end side link hub with respect to the proximal end side link hub. A method for controlling the operation of said actuator,
The posture control for controlling the operation of each actuator and changing the link hub on the distal end side to an arbitrary posture by the synchronous control that controls so that all the actuators start the operation at the same time and complete the operation at the same time. And performing a synchronization control and a posture control by setting deceleration times of all the actuators in the vicinity of one cycle of the resonance frequency of the link actuator.   2. The method of controlling a link operating device according to claim 1, wherein the deceleration time is set within a range of 0.8 to 1.2 periods of a resonance frequency of the link operating device.   3. The link actuator control method according to claim 1, wherein the acceleration time of all the actuators is set near one cycle of the resonance frequency of the link actuator, and the synchronization control and the attitude control are performed.   4. The method for controlling a link actuator according to claim 3, wherein the acceleration time is set within a range of 0.8 to 1.2 periods of a resonance frequency of the link actuator.   5. The posture control according to claim 1, wherein the attitude control determines a command operation amount for each of the actuators based on a target attitude of the link hub on the distal end side, and the synchronous control includes all the synchronization controls. A control method for a link actuating device, wherein the operating speed of each actuator is set according to the ratio of the commanded operation amount of the actuator. 6. The connecting end of a central link member rotatably connected to the base end side end link member according to claim 5, wherein a rotation angle of the base end side end link member with respect to the base end side link hub is βn. The angle formed between the shaft and the connecting end shaft of the central link member rotatably connected to the end link member on the front end side is γ, and each base end on the base end link member serving as a reference The circumferential separation angle of the link member is δn, the vertical angle at which the central axis of the distal link hub is inclined with respect to the central axis of the proximal link hub is θ, and the proximal link hub When the horizontal angle at which the central axis of the link hub on the distal end side is inclined with respect to the central axis is φ,
cos (θ / 2) sinβn−sin (θ / 2) sin (φ + δn) cosβn + sin (γ / 2) = 0
The target rotation angle of each base end side end link member in the posture control is obtained by inversely transforming the expression represented by the formula, and the target rotation angle and each base end side end are obtained. A control method for a link actuating device that calculates a command operation amount of each actuator based on a difference from a current rotation angle of a local link member. 6. The connecting end of a central link member rotatably connected to the base end side end link member according to claim 5, wherein a rotation angle of the base end side end link member with respect to the base end side link hub is βn. The angle formed between the shaft and the connecting end shaft of the central link member rotatably connected to the end link member on the front end side is γ, and each base end on the base end link member serving as a reference The circumferential separation angle of the link member is δn, the vertical angle at which the central axis of the distal link hub is inclined with respect to the central axis of the proximal link hub is θ, and the proximal link hub When the horizontal angle at which the central axis of the link hub on the distal end side is inclined with respect to the central axis is φ,
cos (θ / 2) sinβn−sin (θ / 2) sin (φ + δn) cosβn + sin (γ / 2) = 0
A table showing the relationship between the posture of the distal end side link hub with respect to the proximal end side link hub and the rotation angle of the end link member on each proximal end side by inversely transforming the expression expressed by The target rotation angle of each base end side end link member in the posture control is obtained using this table, and the target rotation angle and each base end side end link member are obtained. A control method for a link actuating device that calculates a command operation amount of each actuator based on a difference from a current rotation angle. The operating speed of each actuator according to any one of claims 5 to 7, wherein the operating speed is Vn, the base speed is V, the current rotation angle of the end link member on the base end side is βn, When the target rotation angle of the base end side end link member in the posture control is βn ′,

The control method of the link actuator which calculates using the formula represented by this. 8. The operating speed of each actuator according to claim 5, wherein the operating speed is Vn, the maximum speed is Vmax, the current rotation angle of the end link member on the base end side is βn, When the target rotation angle of the base end side end link member in the posture control is βn ′, and the maximum value of (βn′−βn) is Δβmax,
Vn = Vmax (βn′−βn) / Δβmax
The control method of the link actuator which calculates using the formula represented by this.   The actuator according to any one of claims 1 to 9, wherein the three or more sets of link mechanisms are each provided with an actuator for arbitrarily changing the attitude of the distal end side link hub with respect to the proximal end side link hub, A control method of a link actuator that controls each of these actuators by redundant control.   11. The resonance frequency detecting sensor according to claim 1, wherein a resonance frequency detecting sensor for detecting a resonance frequency of the link actuator is installed on the link hub on the distal end side, and resonance is performed by a resonance frequency measuring device from the signal. A control method for a link actuator, which calculates a frequency and updates set values of acceleration time and deceleration time of the actuator from the calculation result.   12. The method for controlling a link operating device according to claim 11, wherein an acceleration pickup is used as the resonance frequency detection sensor and an FFT analyzer is used as the resonance frequency measuring device. The link hub on the distal end side is connected to the link hub on the proximal end side through three or more sets of link mechanisms in such a manner that the posture can be changed, and each of the link mechanisms includes a link hub on the proximal end side and a link hub on the distal end side. End link members on the base end side and the tip end side, one end of which is rotatably connected to the link hub, and a center on which both ends are rotatably connected to the other ends of the end link members on the base end side and the tip end side, respectively. Each of the link mechanisms is a geometric model in which the link mechanism is represented by a straight line, and the base end side portion and the tip end side portion are symmetrical with respect to the center portion of the center link member, In the link operating device, of the three or more sets of link mechanisms, two or more sets of link mechanisms are provided with an actuator for arbitrarily changing the attitude of the distal end side link hub with respect to the proximal end side link hub. An apparatus for controlling the operation of said actuator,
The posture control for controlling the operation for each actuator and changing the link hub on the distal end side to an arbitrary posture by synchronous control for controlling all the actuators to start operation simultaneously and complete the operation simultaneously. And a synchronization / attitude control means for performing the synchronization control and attitude control by setting the deceleration time of all the actuators to around one period of the resonance frequency of the link actuator. Actuator control device.

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