WO2023167075A1 - 駆動機構およびこれを備えるロボットアーム - Google Patents

駆動機構およびこれを備えるロボットアーム Download PDF

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Publication number
WO2023167075A1
WO2023167075A1 PCT/JP2023/006497 JP2023006497W WO2023167075A1 WO 2023167075 A1 WO2023167075 A1 WO 2023167075A1 JP 2023006497 W JP2023006497 W JP 2023006497W WO 2023167075 A1 WO2023167075 A1 WO 2023167075A1
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Prior art keywords
drive mechanism
elastic
elastic member
mechanism according
preload
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PCT/JP2023/006497
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English (en)
French (fr)
Japanese (ja)
Inventor
光樹 土屋
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住友重機械工業株式会社
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Priority to JP2024504646A priority Critical patent/JPWO2023167075A1/ja
Publication of WO2023167075A1 publication Critical patent/WO2023167075A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J17/00—Joints

Definitions

  • the present invention relates to a drive mechanism and a robot arm including the same.
  • SEA Series Elastic Actuators
  • An SEA is an actuator in which an elastic element is connected in series to a motion transmission part.
  • the rigidity of this series elastic element is lower than that of a speed reducer, and it is often arranged between the low speed side of the speed reducer and a link arm. .
  • the series elastic element increases mechanical compliance, reduces the risk of damage to the joint mechanism due to external impact forces, and further improves safety in interaction with people and the work environment.
  • VSA Variable Stiffness Actuator
  • SEA is a method of passively enhancing compliance. Since it depends on the stiffness of the series elastic elements, it is basically impossible to change the stiffness after assembly unlike the VSA. On the other hand, unlike the VSA, it does not require a mechanism or drive system for changing rigidity, so the joint can be made simple and compact.
  • VSA Variable Stiffness Actuator
  • the present invention passively changes the stiffness to increase the impact force mitigation effect, and realizes nonlinear elasticity while maintaining a certain level of stiffness, thereby improving the back drivability.
  • Another object of the present invention is to provide a drive mechanism that does not require the addition of an external drive system, and a robot arm equipped with the drive mechanism.
  • One aspect of the present invention is a driving unit configured to be drivable; a driven part driven by receiving the driving force of the driving part; an elastic portion configured by a plurality of elastic members including at least a first elastic member and a second elastic member arranged in series between the driven portion and the driving portion; The first elastic member functions until a predetermined load acts on the elastic portion, and when the load exceeds a predetermined value, the load is also applied to the second elastic member to switch the rigidity of the elastic portion. and A drive mechanism comprising
  • the switching portion applies a predetermined preload to the second elastic member, which is large enough to prevent the second elastic member from functioning until the load acting on the elastic portion exceeds a predetermined value. It may include a mechanism.
  • the drive mechanism of the aspect described above may further include a preload adjusting device that adjusts the magnitude of the preload.
  • the second elastic member in the drive mechanism of the aspect described above is a coil spring
  • the preload adjusting device is configured as a device for adjusting the magnitude of the preload applied to the coil spring by changing the length of the coil spring.
  • the preload adjusting device may include a wedge member that changes the length of the coil spring by wedge action when it moves relative to the coil spring.
  • At least one pair of second elastic members may be provided in the drive mechanism of the above aspect.
  • the paired second elastic members may be arranged symmetrically.
  • the second elastic members may be arranged symmetrically about the neutral axis before the paired second elastic members are relatively deformed with respect to the driven portion. .
  • the paired second elastic members may be arranged in series.
  • a load transmission body may be interposed between the first elastic member and the second elastic member.
  • the load transmission body may be composed of relatively rotatable rollers.
  • the roller in the driving mechanism of the above aspect may be configured to be relatively rotatable with respect to the driven part.
  • the impact force mitigation effect can be enhanced by passively changing the rigidity, and back drivability is improved by realizing non-linear elasticity while maintaining a certain level of torsional rigidity. It is possible to provide a drive mechanism and a robot arm having the drive mechanism that do not require the addition of an external drive system.
  • FIG. 1 is a perspective view showing an example of a robot arm according to one embodiment of the present invention
  • FIG. Fig. 2 is a side view of a robot arm
  • FIG. 3 is a diagram of the robot arm viewed from the direction indicated by reference numeral III in FIG. 2
  • It is a schematic diagram explaining the principle of a drive mechanism.
  • 4A and 4B are graphs showing the relationship between the torsion angle ⁇ t and the torsion torque ⁇ , and (B) the graph showing the relationship between the torsion angle ⁇ t and the torsion rigidity S, both of which describe the characteristics of the elastic portion of the drive mechanism;
  • FIG. 4 is a diagram showing a drive mechanism according to an embodiment of the present invention, in which the joints of the robot arm shown in FIG.
  • FIG. 6 is a diagram schematically showing a transmission path of a driving force from a driving portion (reducer output shaft 10) to a driven portion (second ring 62) in the driving mechanism or a load generated by the driving force;
  • FIG. FIG. 6 is a diagram showing a configuration example of the preload applying mechanism in the switching unit, and is a view of the one located in the 12 o'clock direction of the four preload applying mechanisms in FIG. 6 seen from above in FIG. plan view).
  • FIG. 7 is a diagram showing a configuration example of a preload applying mechanism in a switching unit, showing an enlarged view of one positioned in the 12 o'clock direction among the four preload applying mechanisms in FIG. 6 .
  • FIG. 10 is a diagram showing (A) the second link side where the drive section is located and (B) the third link side where the driven section is located in a state (state [3]) in which the output shaft of the speed reducer is further rotated;
  • FIG. 10 is a diagram showing (A) the side of the second link where the drive section is located and (B) the side of the third link where the driven section is located, respectively, in a situation where an external force acts on the third link of the robot arm;
  • FIG. 10 is a diagram showing (A) the side of the second link where the drive section is located and (B) the side of the third link where the driven section is located in a situation where a larger external force acts on the third link of the robot arm;
  • 1 is a block diagram showing an example of a control device for a robot arm;
  • FIG. 10 is a diagram showing (A) the side of the second link where the drive section is located and (B) the side of the third link where the driven section is located, respectively, in a situation where an external force acts on the third link of the robot arm;
  • FIG. 10 is a diagram showing (A) the side of the second link where the drive section is located and (B) the side of the third link where the driven section is located in a situation where a larger
  • the robot arm 100 is a vertical multi-joint robot arm with multiple joints (for example, four axes), and includes a base 100B and a plurality of links connected to the base.
  • the link has an actuator 9 (see FIGS. 3 and 14) rotatably provided with respect to the link to rotate the next link along the axis of rotation (see FIG. 1, etc.).
  • the robot arm 100 in this embodiment includes a first link 101, a second link 102, a third link 103, and a hand 104 (see FIGS. 1 to 3).
  • the surface of the base 100B is defined as an xz plane defined by the x-axis and the z-axis, and the axis perpendicular to the xz-plane is defined as the y-axis.
  • the axis will be used for explanation.
  • the first link 101 is rotatably provided around the y-axis (an axis parallel to) with respect to the base 100B, and rotates the second link 102 and the like along the xz plane (see FIG. 1, etc.).
  • the second link 102 includes a link arm rotatable relative to the first link 101 about an axis perpendicular to the y-axis (an axis parallel to the xz plane).
  • the third link 103 includes a link arm rotatable relative to the second link 102 about an axis perpendicular to the y-axis (an axis parallel to the xz plane).
  • a hand 104 used for gripping a workpiece (not shown) is provided at the tip of the third link 103 so as to be rotatable (swivelable) around a central axis 103c extending in the longitudinal direction of the third link 103 .
  • Members such as the links 101 to 103 and the hand 104 (in this specification, the side that applies the driving force is referred to as the driving portion, and the side that receives the driving force from the driving portion and is driven by the member is referred to as the driven portion.
  • control device 200 is a control device 200 (although detailed description is omitted in this specification, the control device 200 includes various components such as a start position acquisition unit, a target position acquisition unit, a route acquisition unit, a control command acquisition unit, a storage unit, and the like). It is configured to function as a part), and is driven by an actuator 9 to perform a predetermined operation (see FIG. 14). In addition, a joint functioning as a joint (in this specification and the drawings, a 110) is provided (see FIG. 1, etc.).
  • the joint part 110 is provided with a drive mechanism 1 having a structure in which an elastic element is connected in series to a motion transmission part that transmits driving force from the drive part to the driven part.
  • the drive mechanism 1 is provided for each of the joints 110, and although the detailed structure may differ depending on the structure of each joint 110, basically, the mechanical compliance is enhanced by the elastic element, It is configured to reduce the risk of damage to the joints 110 due to external impact force and improve safety in interaction with people and work environments.
  • the drive mechanism 1 in this embodiment includes a drive portion (for example, a speed reducer output shaft 10 to be described later), a driven portion (for example, a second ring 62 to be described later), an elastic portion 1E, a switching portion 50, and the like.
  • the elastic portion 1E is composed of a plurality of elastic members including a first elastic member 11 and a second elastic member 41 arranged in series between the driven portion and the driving portion.
  • the switching portion 50 only the first elastic member 11 functions (deforms) until the load acting on the elastic portion 1E reaches a predetermined value (that is, until the predetermined load acts), and the load reaches the predetermined value. When it exceeds, the load acts on the second elastic member 41, so that the second elastic member 41 also functions (further deforms from the state in which the preload is applied), thereby switching the rigidity of the elastic portion 1E. It is configured.
  • the driving mechanism 1 including the elastic portion 1E and the switching portion 50 configured in this manner the spring stiffness of the elastic portion 1E as a whole (for example, , torsional stiffness) can be switched.
  • FIGS. 4 and 5 the principle and features of such a drive mechanism 1 will be described (see FIGS. 4 and 5), and then the specific structure will be described (see FIG. 6, etc.).
  • FIG. 4 shows a schematic configuration of the drive mechanism 1 of this embodiment, and FIG. 5 shows changes in characteristics (spring stiffness) during operation.
  • Symbol [1] in FIG. 4 indicates a state where the load is 0,
  • [2] indicates a state where the load is applied and only the first elastic member 11 is functioning, and
  • [3] indicates a load exceeding a predetermined value.
  • a state in which both the first elastic member 11 and the second elastic member 41 are functioning is shown.
  • first elastic members 11 are arranged on both sides of a driving piece 10t of a driving portion (for example, a speed reducer output shaft) 10, and second elastic members 12 are arranged on the outside thereof.
  • the driving force is transmitted to the driven portion 62 through the first elastic member 11 and the second elastic member 41 regardless of whether the is operated (rotated) clockwise or counterclockwise.
  • the first elastic member 11 and the second elastic member 41 can be considered to be, for example, torsion coil springs.
  • a member denoted by reference numeral 50 between the first elastic member 11 and the second elastic member 41 represents a switching portion. Symbols [1] to [3] in FIG. 5 indicate changes in characteristics corresponding to states [1] to [3] shown in FIG.
  • the clockwise rotation of the driving piece 10t corresponds to the amount of displacement of the driving piece 10t that moves accordingly.
  • the first elastic member 11 located in the direction is compressed and deformed (state [2] shown in FIG. 4).
  • the function of the switching portion 50 prevents the second elastic member 41 from deforming.
  • the driving force (torsion torque ⁇ ) acting from the drive section 10 to the driven section 62 linearly changes in proportion to the torsion angle ⁇ t of the drive section 10 (Fig. 5 (A)).
  • the torsional stiffness S in such state [2] is constant regardless of the magnitude of the torsional angle ⁇ t (see FIG. 5(B)).
  • This property (the property that the torsional stiffness is constant regardless of the magnitude of the torsion angle) is similar to that in conventional direct elastic actuators (SEA).
  • the switching portion 50 changes to a state (state [3]) in which the load acting by the driving force is also applied to the second elastic member 41 .
  • state [3] the state in which the spring rigidity of the elastic portion 1E as a whole is equal to the spring rigidity of only the first elastic member 11 (state [2]) is changed to the state in which the first elastic member 11 and the second elastic member 41 are connected in series. It switches to the spring stiffness according to the spring constant of the spring.
  • the subsequent torsional torque ⁇ changes differently from the state [2], specifically, the degree of change is smaller than that in the state [2] (see FIG. 5A), and the torsional stiffness S is lower than state [2] (see FIG. 5(B)).
  • the drive mechanism 1 of the present embodiment based on such a principle is based on the conventional system of passively increasing the compliance like SEA, but after a specific torsional angle ⁇ t , the torsional rigidity S decreases. It has structure. This is different from the conventional mechanism in which the torsion torque ⁇ had to change linearly according to the torsion angle ⁇ t . This leads to further improvements in back drivability, safety for humans, the surrounding environment, and internal equipment of the robot arm 100 . Moreover, since the drive mechanism 1 of the present embodiment includes the switching unit 50 that is mechanically configured to switch the spring rigidity according to the change in the load according to the torsion angle ⁇ t , an external drive system can be added. It is possible to switch autonomously without The specific structure and characteristics of the switching unit 50 will be further clarified by specific examples of the drive mechanism 1 described below.
  • the drive mechanism 1 of the present embodiment includes a speed reducer output shaft (drive portion) 10, an annular spring (first elastic member) 11, a first ring 21, rollers 31 to 34, coil springs (second elastic members) 41 to 44. , a switching portion 50, a second ring (driven portion) 62, and the like (see FIG. 6, etc.). These elements are built in respective housings 112 and 113 of the second link 102 and the third link 103 (see FIGS. 1, 3, etc.).
  • Each of these elements has a driving force of actuator (motor) 9 ⁇ speed reducer output shaft 10 ⁇ annular spring (first elastic member) 11 ⁇ first ring 21 ⁇ rollers 31 to 34 ⁇ coil spring (second elastic member) 41 to 44 ⁇ second ring (driven portion) 62 in order (see FIG. 7).
  • actuator motor
  • annular spring first elastic member
  • second elastic member second elastic member 41 to 44 ⁇ second ring (driven portion) 62
  • a plurality of elastic members in the present embodiment, two kinds of springs, namely, an annular spring 11 and coil springs 41 to 44
  • springs 41 to 44 are mechanically arranged in series with rollers 31 to 34 interposed therebetween (see FIG. 7).
  • the speed reducer output shaft 10 moderately reduces the rotational speed in the final stage of the path for transmitting the driving force of the actuator 9 (see FIGS. 3 and 14) that drives the third link 103, and then transfers to the third link 103. It is a member that outputs and functions as a drive unit (see FIG. 6, etc.).
  • the speed reducer output shaft 10 of this embodiment is configured to rotate either clockwise or counterclockwise in the drawing.
  • the annular spring 11 is an example of a first elastic member and is provided between the speed reducer output shaft 10 and the first ring 21 .
  • the inner ends 11i of the pair of annular springs 11a and 11b, which are curved plate springs, are fixed around the speed reducer output shaft 10, and the outer ends 11o are fixed. is fixed to the inner peripheral surface of the first ring 21 located on the outer peripheral side (see FIG. 6, etc.).
  • the annular spring 11 (11a, 11b) of the present embodiment is elastically deformed so as to expand outward when the speed reducer output shaft 10 rotates clockwise in the drawing, and attaches the first ring 21 in that direction (clockwise). When the force (see FIGS. 10 and 11) is applied, the output shaft 10 of the speed reducer rotates in the counterclockwise direction (not shown). counterclockwise).
  • the first ring 21 is an annular member that is biased by the annular spring 11 and rotates so as to follow the speed reducer output shaft 10 when the annular spring 11 is elastically deformed (see FIG. 6, etc.).
  • the first ring 21 of this embodiment is incorporated in the housing 112 of the second link 102 and is rotatably held by a bearing 23 such as a ball bearing (see FIG. 6, etc.).
  • the rollers 31 to 34 are mechanically interposed between the annular spring 11 and the coil springs 41 to 44, which are provided in series and directly constitute elastic elements. It is provided as a load transmitting body that transmits to the springs 41 to 44 (see FIG. 6, etc.).
  • the rollers 31 to 34 of this embodiment are composed of rolling elements that are rotatably attached to the 21st ring, and each of the rollers 31 to 34 is a third roller in the housing 113 of the third link 103. 2 It is arranged at a position where it can press each of the coil springs 41 to 44 provided in the ring (driven portion) 62 to transmit the load (see FIG. 6).
  • rollers 31 to 34 which are rotatably mounted, are also rotatable relative to the second ring (driven portion) 62, and when moving within the second ring (driven portion) 62, The resistance during movement is reduced by using rolling resistance instead of slip resistance (see FIG. 11, etc.).
  • the coil springs (second elastic members) 41 to 44 are elastic members that are mechanically arranged in series with the annular spring 11 and constitute the elastic portion 1E directly composed of elastic elements. These coil springs 41 to 44 are formed in the second ring 62 at intervals of 90 degrees in the circumferential direction.
  • a pair of spring installation spaces 65 are installed in each of the spring installation spaces 65 (see FIGS. 6 and 8, etc.).
  • a pair of coil springs 41a and 41b arranged in one installation space 65 are symmetrically arranged in series across a virtual neutral axis (indicated by symbol NL in FIG. 9) on which the roller 31 is positioned.
  • the paired coil springs 41a and 41b are guided by a cylindrical direct-acting guide 66 arranged inside (see FIGS. 8 and 9). It should be noted that the linear motion guide 66 is preferably made of a resin material or the like whose surface has a low coefficient of dynamic friction. These coil springs 41a and 41b are compressed by a preload applying mechanism 51 and are always preloaded.
  • the second ring 62 is an annular member that is rotationally driven by receiving a driving force transmitted from the reduction gear output shaft (driving portion) 10 via the elastic portion 1E (annular spring 11 and coil springs 41 to 44). .
  • the second ring 62 of this embodiment is incorporated in the housing 113 of the 32-link 103, and is rotatably held by a bearing 63 such as a ball bearing (see FIG. 6, etc.).
  • the switching portion 50 deforms only the annular spring 11 until a predetermined load acts on the elastic portion 1E (the annular spring 11 and the coil springs 41 to 44). Not only the spring 11 but also the coil springs 41 to 44 are acted upon to switch the rigidity of the elastic portion 1E. In this embodiment, such a function of the switching section 50 is realized using the preload applying mechanism 51 .
  • the preload applying mechanism 51 applies a predetermined preload that does not cause the coil springs 41 to 44 to function (further deformation from the preloaded state) until the load acting on the elastic portion 1E exceeds a predetermined value. It is a device composed of a mechanism for applying to 41-44.
  • the preload applying mechanism 51 of this embodiment is configured as a device that further includes a preload adjusting device 52 that adjusts the magnitude of the preload (see FIGS. 8 and 9, etc.).
  • the preload adjusting device 52 is a device for adjusting the length of the coil springs 41 to 44 to continuously increase or decrease the magnitude of the preload applied to the coil springs.
  • the wedge member 53 of this embodiment includes a central wedge member 53c, a pair of both side wedge members 53a and 53b, a central wedge adjusting bolt 54c, both side wedge fixing bolts 54a and 54b, and pressing pieces 55a and 55b. Includes (see FIG. 8, etc.).
  • the central wedge member 53c has a substantially trapezoidal shape (or a triangular shape or the like), and is attached to the second ring 62 by a central wedge adjusting bolt 54c so as to be movable in the y-axis direction (see FIG. 9, etc.). .
  • the central wedge adjusting bolt 54c has its tip screwed to the second ring 62 while passing through the central wedge member 53c.
  • the position of the central wedge member 53c in the y-axis direction can be adjusted by rotating the head of the central wedge adjusting bolt 54c positioned at the back of the hole 62c by putting a screwdriver or the like on the head thereof. (See Figure 8).
  • the both side wedge members 53a and 53b are members arranged in contact with both sides of the central wedge member 53c. They approach or separate (see FIG. 9, etc.). These two-side wedge members 53a and 53b are fixed to the second ring 62 by tightening two-side wedge fixing bolts 54a and 54b (see FIG. 8, etc.).
  • the fixing bolts 54a and 54b are movable in the x-axis direction along long holes 62a and 62b formed in the second ring 62.
  • both side wedge members 53a and 53b When the fixing bolts 54a and 54b are loosened, the fixing bolts 54a and 54b The x-axis direction positions of both side wedge members 53a and 53b can be changed, and when the fixing bolts 54a and 54b are loosened, the x-axis direction positions of both side wedge members 53a and 53b are fixed at the positions.
  • These wedge members 53a and 53b are configured to press and compress the coil springs 41 (41a and 41b) via pressing pieces 55a and 55b (see FIG. 8). By pressing and compressing the coil springs 41 (41a, 41b) by the pressing pieces 55a, 55b, the coil springs 41 (41a, 41b) can be preloaded.
  • the roller 31 (to 34) is arranged on the neutral axis NL between the pair of pressing pieces 55a and 55b.
  • the load is transmitted to the coil springs 41 (41a, 41b) in this state.
  • the wedge members 53a and 53b and the pressing pieces 55a and 55b are not connected to each other (not integrated).
  • the pressing piece 55a when the roller 31 moves counterclockwise (to the left in the x-axis direction in the drawing), the pressing piece 55a also moves, but the wedge member 53a is fixed and does not move.
  • the pressing piece 55b on the opposite side is pressed against the wedge member 53b by the preload of the coil spring 41 (41b) and stops.
  • the position of the central wedge member 53c is adjusted while the fixing bolts 54a and 54b are loosened.
  • the coil springs 41 (41a, 41b) are compressed via the pressing pieces 55a, 55b.
  • the preload applied to the coil springs 41 (41a, 41b) increases, and the threshold value (predetermined value) at which the rigidity of the elastic portion 1E is switched increases.
  • the central wedge adjustment bolt 54c when the central wedge adjustment bolt 54c is turned in the opposite direction, the central wedge member 53c pressed by the two wedge members 53a and 53b moves along the y-axis direction in FIG.
  • the coil springs 41 (41a, 41b) expand as the two side wedge members 53a, 53b move toward the central wedge member 53c as they are pushed upward.
  • the preload applied to the coil springs 41 (41a, 41b) is reduced, and the threshold value (predetermined value) at which the rigidity of the elastic portion 1E is switched is reduced.
  • the preload can be applied evenly to the paired coil springs 41 (41a, 41b), and one adjustment can be performed. Since the magnitude of the preload applied to the coil springs 41 (41a, 41b) can be simultaneously adjusted by the means (central wedge adjustment bolt 54c), work such as adjustment can be performed efficiently.
  • This state corresponds to the above-described state [2] in which only the annular spring 11 is elastically deformed and the behavior of the torsional torque ⁇ and the torsional rigidity S of the elastic portion 1E depends only on the characteristics of the annular spring 11 (FIG. 5). reference).
  • the driving force (torsion torque ⁇ ) acting from the speed reducer output shaft 10 to the second ring 62 changes linearly in proportion to the torsion angle ⁇ t
  • the torsion stiffness S is proportional to the torsion angle ⁇ t . It is constant regardless of the size (see Fig. 5).
  • the annular spring 11 is further elastically deformed, and urges the coil spring 41a with a greater urging force via the roller 31 and the pressing piece 55a (see FIG. 11A).
  • this biasing force exceeds the magnitude of the predetermined preload applied to the coil spring 41a, the coil spring 41 is compressed and deformed. That is, the state [2] in which only the annular spring 11 is elastically deformed is switched to the state [3] in which both the annular spring 11 and the coil spring 41 are deformed.
  • a counterclockwise torque in FIG. 11(B) acts on the second ring 62, and in response to this torque, the second ring 62 rotates counterclockwise in FIG. reference).
  • the torsion angle ⁇ t of the roller 31 and the first ring 21 increases, and the elastic deformation amount of the annular spring 11 also increases (see FIG. 13).
  • the biasing force acting on the coil spring 41a from the elastically deformed annular spring 11 via the roller 31 and the pressing piece 55a exceeds the magnitude of the predetermined preload applied to the coil spring 41a.
  • the coil spring 41 is compressed and deformed (see FIG. 13B). That is, the state [2] in which only the annular spring 11 is elastically deformed is switched to the state [3] in which both the annular spring 11 and the coil spring 41 are deformed, and the spring rigidity of the elastic portion 1E as a whole changes to the annular state.
  • the state (state [2]) equal to the spring stiffness of the spring 11 alone is switched to the spring stiffness corresponding to the spring constant of the series spring composed of the annular spring 11 and the coil spring 41 (see FIG. 5).
  • the drive mechanism 1 passively changes its rigidity when a larger external force acts on it, thereby mitigating the external force such as impact force.
  • the annular spring (first elastic member) 11 elastically deforms when the load acting on the elastic portion 1E composed of the series elastic element is less than a predetermined value.
  • the load exceeds a predetermined value, not only the annular spring 11 but also the coil springs (second elastic members) 41 to 44 are switched to an elastically deformed state. also switches to a different state.
  • the rigidity torsional rigidity
  • the rigidity is constant regardless of the magnitude of the load. 10
  • the torsion angle can be increased under the condition of relatively small force, thereby realizing the characteristic of high compliance.
  • the robot arm 100 when the robot arm 100 comes into strong contact with a person and an impact force acts, the elasticity is passively changed non-linearly at the moment when the load exceeds a predetermined value.
  • the robot arm 100 maintains a certain level of rigidity during operation, while the rigidity is low in situations where the requirements for higher safety and higher back drivability should be satisfied.
  • By passively switching to it is possible to soften the impact force from the outside and reduce the risk of damage to the joint mechanism.
  • the force accuracy increases in force control by controlling the torsion angle ⁇ t .
  • the characteristics of the driving mechanism 1 as described above, more specifically, the rigidity of the elastic portion 1E in each of the states [1] and [2] are determined by the annular spring 11 as the first elastic member and the second elastic member It can be adjusted by changing the spring stiffness of each of the barrel springs 41-44.
  • the drive mechanism 1 configured as described above can be used as a mechanism that constitutes the joints of the robot arm 100, and is used in various fields such as production sites, welfare/medical care, agriculture, service, and entertainment. Further, it can be applied to joints of various robots such as ankle joints of walking robots and joint mechanisms of assist suits.
  • the above-described embodiment is a preferred example of the present invention, it is not limited to this, and can be modified in various ways without departing from the gist of the present invention.
  • the drive mechanism 1 including two types of elastic elements, the annular spring 11 as the first elastic member and the coil springs 41 to 44 as the second elastic members, was described, but this is only a preferred example. do not have.
  • the elastic portion 1E of the driving mechanism 1 is composed of three or more elastic members arranged in series between the driving portion (for example, the speed reducer output shaft 10) and the driven portion (for example, the second ring 62). good too.
  • the driving mechanism 1 including the annular spring 11 and the coil springs 41 to 44 has been described. Needless to say, the driving mechanism 1 can be configured by elastic members other than the annular spring 11 and the coil springs 41-44.
  • [Appendix 1] a driving unit configured to be drivable; a driven part driven by receiving the driving force of the driving part; an elastic portion configured by a plurality of elastic members including at least a first elastic member and a second elastic member arranged in series between the driven portion and the driving portion; The first elastic member functions until a predetermined load acts on the elastic portion, and when the load exceeds a predetermined value, the load is also applied to the second elastic member to switch the rigidity of the elastic portion.
  • a switching unit configured to A drive mechanism.
  • Appendix 3 3. The drive mechanism according to appendix 2, further comprising a preload adjustment device that adjusts the magnitude of the preload.
  • Appendix 5 The drive mechanism according to appendix 4, wherein the preload adjustment device includes a wedge member that changes the length of the coil spring by wedge action when relatively displaced with respect to the coil spring.
  • Appendix 7 The drive mechanism according to appendix 6, wherein the paired second elastic members are arranged symmetrically.
  • Appendix 8 8. The driving mechanism according to appendix 7, wherein the paired second elastic members are arranged symmetrically about a neutral axis of the paired second elastic members before they are relatively deformed with respect to the driven portion.
  • Appendix 9 9. The drive mechanism according to any one of appendices 6 to 8, wherein the pair of second elastic members are arranged in series.
  • Appendix 10 10. The drive mechanism according to any one of appendices 1 to 9, wherein a load transmission body is interposed between the first elastic member and the second elastic member.
  • Appendix 11 11. The drive mechanism according to appendix 10, wherein the load transmission body is composed of a relatively rotatable roller.
  • Appendix 12 12. The driving mechanism according to appendix 11, wherein the roller is configured to be relatively rotatable with respect to the driven part.
  • Appendix 13 A drive mechanism according to any one of Appendices 1 to 12; a link provided with the drive unit of the drive mechanism according to appendix 1; and a link on which the driven portion of the drive mechanism according to appendix 1 is provided.
  • the present invention is suitable for application to a drive mechanism and a robot arm including the same.

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  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Manipulator (AREA)
PCT/JP2023/006497 2022-03-04 2023-02-22 駆動機構およびこれを備えるロボットアーム WO2023167075A1 (ja)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003266358A (ja) * 2002-03-18 2003-09-24 Sony Corp ロボット装置及び関節軸駆動装置
CN203460186U (zh) * 2013-07-15 2014-03-05 北京理工大学 能够提供非线性可变刚度的弹性组件
JP2023005544A (ja) * 2021-06-29 2023-01-18 トヨフレックス株式会社 付勢力発生装置及び動作補助装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003266358A (ja) * 2002-03-18 2003-09-24 Sony Corp ロボット装置及び関節軸駆動装置
CN203460186U (zh) * 2013-07-15 2014-03-05 北京理工大学 能够提供非线性可变刚度的弹性组件
JP2023005544A (ja) * 2021-06-29 2023-01-18 トヨフレックス株式会社 付勢力発生装置及び動作補助装置

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