Joint device and method for controlling the joint device

Abstract

A motorized artificial leg (1) comprises a below-knee member (10), an above-knee member (20), a knee joint mechanism (30) that links the below-knee member (10) and the above-knee member (20) such that the angle formed therebetween can be changed, and a lengthening and shortening device (40) that can change the angle formed between the below-knee member (10) and the above-knee member (20) by lengthening and shortening. The lengthening and shortening device (40) comprises a motor (M) and a transmission (T) that transmits motive force from the motor (M). The transmission (T) comprises a first transmission mechanism (T1) that transmits motive force from the motor (M) at a first gear ratio and a second transmission mechanism (T2) that transmits motive force from the motor (M) at a second gear ratio that is different from the first gear ratio.

Description

Technical Field

[0001] The present invention relates to a joint device , and control method for joint devices .

Background Art

[0002] Conventionally, as a joint device used for a connecting portion that connects two members, there is known one provided with a telescopic device capable of changing the angle formed by the two members. As such a joint device, for example, there is a prosthetic leg used for a knee joint. Patent Document 1 describes that a sensor for detecting the contraction movement of the muscle at the stump end of a severed leg is provided in the thigh socket of the prosthetic leg attached to the stump end of the severed leg, and the throttle degree of the variable valve of the hydraulic cylinder for adjusting the resistance of flexion and extension of the knee joint portion is controlled by the detection information from the sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prosthetic leg described in Patent Document 1, although it is possible to generate resistance to flexion and extension, it is not possible to generate power for flexion and extension. In particular, in order to smoothly ascend a staircase, it was necessary to extend the knee joint while a load was acting.

[0005] The present invention provides a joint device capable of extending and flexing a connecting portion by the power of a power source , and control method for joint devices .

Means for Solving the Problems

[0006] The first invention is a first member, a second member, A connecting portion that connects the first member and the second member in a way that allows the angle between them to be changed, A joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, The system includes a second power transmission path that transmits the power at a second gear ratio different from the first gear ratio, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The aforementioned joint device is The power source and the control unit that controls the first and second intermittent mechanisms, The device further comprises a load acquisition unit that acquires the load applied to the aforementioned joint device, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the load acquired by the load acquisition unit.

[0007] The second invention is, First member and The second member and A connecting portion that connects the first member and the second member in a way that allows the angle between them to be changed, A control method for a joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The control method described above is A load acquisition step for acquiring the load applied to the aforementioned joint device, The system comprises an intermittent control step for controlling the first intermittent mechanism and the second intermittent mechanism, The intermittent control step controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the load acquired in the load acquisition step.

[0008] The third invention is a first member, a second member, a connecting portion that connects the first member and the second member so as to be able to change the angle formed therebetween, a telescopic device that can change the angle formed between the first member and the second member by telescoping, and is a joint device comprising: The telescopic device comprises a power source, and a power transmission portion that transmits the power of the power source, The power transmission portion comprises a first power transmission path that transmits the power at a first speed ratio, and a second power transmission path that transmits the power at a second speed ratio different from the first speed ratio, [[ID=三十三]] and comprises The telescopic device comprises a first intermittent mechanism that switches between blocking and connecting the power in the first power transmission path, and a second intermittent mechanism that switches between blocking and connecting the power in the second power transmission path, The joint device further comprises a control portion that controls the power source and the first intermittent mechanism and the second intermittent mechanism, and a traveling direction acquisition portion that acquires the traveling direction of the mounting body of the joint device, The control portion controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the traveling direction acquired by the traveling direction acquisition portion. Furthermore, the fourth invention is, First member and The The second member and A connecting portion that connects the first member and the second member in a way that allows the angle between them to be changed, <000,0121> A control method for a joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is <000012,5> Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The control method described above is A process for obtaining the direction of travel of the main body to which the coupling device is attached, The system comprises an intermittent control step for controlling the first intermittent mechanism and the second intermittent mechanism, The intermittent control step controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired in the direction of travel acquisition step. [Effects of the Invention]

[0009] According to the present invention, the connecting portion can be extended and bent via a power transmission portion that transmits power from a power source. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the electric prosthetic leg of the first embodiment of the present invention, taken from a diagonal front view. [Figure 2] Figure 1 is a perspective view of the electric prosthetic leg from a diagonal rearward angle. [Figure 3] Figure 1 shows the internal structure of an electric prosthetic leg. [Figure 4] Figure 1 is an enlarged view of the power transmission section of the electric prosthetic leg. [Figure 5A] This diagram shows the power transmission in the power transmission unit when the power transmission unit in Figure 4 is in the first gear shift state. [Figure 5B] This diagram shows the power transmission in the power transmission unit when the power transmission unit in Figure 4 is in the second gear shift state. [Figure 5C] This diagram shows the power transmission of the power transmission unit when the power transmission unit in Figure 4 is in a free state. [Figure 6] This diagram illustrates the extension of the knee joint mechanism from a flexed position when climbing stairs. [Figure 7]This diagram illustrates the flexion of the knee joint mechanism from an extended position when climbing stairs. [Figure 8] This is a perspective view of the power transmission section of an electric prosthetic leg according to a second embodiment of the present invention. [Figure 9] Figure 8 is a cross-sectional view of the power transmission section. [Figure 10] This is a functional block diagram of the control system in the first example of step-up control. [Figure 11] This diagram illustrates the sensors and other components of the electric prosthetic leg required for the first example of step-up control. [Figure 12] This diagram shows the flow in the first example of step-up control, when the electric prosthesis is on the stance leg side. [Figure 13] This diagram shows the flow in the first example of step-up control, when the electric prosthesis is on the swing leg side. [Figure 14] This graph shows the load and hip joint torque during promotion to the next rank. [Figure 15] This is a functional block diagram of the control system in the second example of step-up control. [Figure 16] This diagram illustrates the sensors and other components of the electric prosthetic leg necessary for the second example of step-up control. [Figure 17] This diagram shows the flow in the second example of step-up control, where the electric prosthesis is on the stance leg side. [Figure 18] The graph shows the relationship between knee joint torque, knee angle, and motor control in the second example of step-up control. [Figure 19] This graph shows the load and hip joint torque during promotion to the next rank. [Modes for carrying out the invention]

[0011] The following describes various embodiments of the electric prosthesis as an example of the joint device of the present invention, and the control of climbing stairs using this electric prosthesis, with reference to the drawings. In the following description, the forward / backward, left / right, and up / down directions are defined relative to the user of the electric prosthesis. In the drawings, the front of the electric prosthesis is Fr, the rear is Rr, the left side is L, the right side is R, the top is U, and the bottom is D.

[0012] <First Embodiment> [Electrified Prosthetic Leg] The electric prosthetic leg 1 of this embodiment is a prosthetic leg for a person without a knee, and as shown in Figures 6 and 7, it is attached to one thigh 4 that rotates relative to the upper body 3 and functions as a lower leg 5. As shown in Figures 1 to 3, the electric prosthetic leg 1 comprises a lower knee member 10 located below the knee, an upper knee member 20 located above the knee, a knee joint mechanism 30 that connects the lower knee member 10 and the upper knee member 20 in a way that allows the angle between them to be changed, and an extendable / retractable device 40 that can change the angle between the lower knee member 10 and the upper knee member 20 by extending or retracting.

[0013] The knee portion 20 comprises an upper wall portion 22 on which an adapter 21 connected to a socket (not shown) is provided, and a pair of upper side wall portions 23 extending downward from both the left and right ends of the upper wall portion 22, and has a substantially U-shape with an opening at the bottom when viewed from the front and rear direction.

[0014] The lower leg member 10 comprises a lower wall portion 12 on which the leg portion 11 is provided, and a pair of lower side wall portions 13 extending upward from both the left and right ends of the lower wall portion 12, and has a substantially U-shape with an opening at the top when viewed from the front and rear direction.

[0015] A pair of lower side walls 13 of the lower knee member 10 are rotatably connected between a pair of upper side walls 23 of the upper knee member 20, with the lower side walls 13 of the lower knee member 10 rotating around a pivot 35. This mechanism allows the angle between the lower knee member 10 and the upper knee member 20 to be changed, thus forming the knee joint mechanism 30.

[0016] A telescopic device 40 is provided in the space formed between the upper knee member 20 and the lower knee member 10, which can change the angle between the lower knee member 10 and the upper knee member 20.

[0017] The telescopic device 40, also referring to Figure 4, comprises a motor M that outputs rotational power, a transmission T that transmits power from the motor M, a first spindle unit SP1 connected to the transmission T in a power-transmitting manner and converting the rotational power output from the transmission T into translational motion, an intermittent mechanism 50 interposed between the motor M and the first transmission mechanism T1 and the second transmission mechanism T2 of the transmission T (described later), and a second spindle unit SP2 that converts the rotational power output from the motor M into translational motion of the actuator 55 of the intermittent mechanism 50.

[0018] The transmission T comprises a transmission case 60 having a rectangular shape when viewed from the front and rear, and comprising a top plate portion 61, a bottom plate portion 62, and a pair of side plate portions 63 connecting the left and right ends of the top plate portion 61 and the bottom plate portion 62. The transmission case 60 has a pair of rotating wings 64 extending downward from the bottom plate portion 62, which are supported by a rotating support wall 14 extending upward from the lower wall portion 12 of the lower knee side member 10 so as to be able to swing around a lower swing portion 70 but not be able to move.

[0019] The motor M is positioned in front of and above the top plate portion 61 of the transmission case 60, such that its output shaft 71 penetrates the top plate portion 61 and protrudes into the interior of the transmission case 60. The first spindle unit SP1 is positioned on the opposite side of the motor M in the front-rear direction, with the intermittent mechanism 50 in between. In other words, the motor M is positioned in front of the intermittent mechanism 50 in the front-rear direction, and the first spindle unit SP1 is positioned behind the intermittent mechanism 50 in the front-rear direction. This makes it possible to maintain balance in the front-rear direction while suppressing the increase in width of the electric prosthesis 1, even when the motor M is mounted on the electric prosthesis 1.

[0020] The second spindle unit SP2, which converts the rotational power output from the motor M into translational motion of the actuator 55 of the intermittent mechanism 50, is positioned between the motor M and the first spindle unit SP1 in the front-rear direction. The output shaft 71 of the motor M, the first spindle 73 of the first spindle unit SP1, and the second spindle 75 of the second spindle unit SP2 are arranged parallel to each other and are positioned to face up and down when the knee joint mechanism 30 is fully extended.

[0021] The first spindle unit SP1 includes a first spindle 73 with a male thread 73a and a sleeve 74 with a female thread 74a. The sleeve 74 moves in translation along the axis of the first spindle 73 as the first spindle 73 rotates. In this embodiment, the first spindle 73 rotates in response to the rotational power of a motor M transmitted by a transmission T. The sleeve 74 is attached to a pair of inner side walls 24 extending downward from the upper wall 22 of the knee-up side member 20, so as to be pivotable and immovable around an upper swinging part 25. Therefore, when the first spindle 73 rotates in one direction (in the direction of arrow D1 in Figure 5A) in response to the rotational power of the motor M transmitted by the transmission T, the sleeve 74 moves in translation away from the transmission T, and when the first spindle 73 rotates in the other direction (in the direction of arrow D2 in Figure 5B), the sleeve 74 moves in translation towards the transmission T.

[0022] In other words, the distance between the sleeve 74 and the transmission T expands or contracts depending on the rotation direction of the first spindle 73. As mentioned above, the sleeve 74 is immovably attached to the upper knee member 20, so as the distance between the sleeve 74 and the transmission T expands or contracts depending on the rotation direction of the first spindle 73, the lower knee member 10 to which the transmission T is attached and the upper knee member 20 to which the sleeve 74 is attached rotate around the pivot part 35. This changes the angle between the upper knee member 20 and the lower knee member 10.

[0023] As shown in Figure 4, the transmission T includes an output gear 72 provided on the output shaft 71 of the motor M, an input gear 77 provided approximately in the center of the second spindle 75 of the second spindle unit SP2 and meshing with the output gear 72, a first transmission mechanism T1, and a second transmission mechanism T2.

[0024] The first gear shifting mechanism T1 consists of a first drive gear 78 that is immovably mounted on the upper side of the second spindle 75 of the second spindle unit SP2, and a first driven gear 79 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the first drive gear 78.

[0025] The second transmission mechanism T2 consists of a second drive gear 80 which is immovably mounted on the lower side of the second spindle 75 of the second spindle unit SP2, and a second driven gear 81 which is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the second drive gear 80.

[0026] The first transmission mechanism T1 transmits power from the motor M at a first gear ratio as the first power transmission path. The second transmission mechanism T2 transmits power from the motor M at a second gear ratio different from the first gear ratio as the second power transmission path. By providing two power transmission paths with different gear ratios, the extension and flexion movement speeds and generated power of the knee joint mechanism 30 can be switched. The first gear ratio and the second gear ratio do not need to be different, and either the first transmission mechanism T1 or the second transmission mechanism T2 may be a reduction mechanism and the other a speed increase mechanism, either one may be a constant speed mechanism and the other a reduction mechanism or a speed increase mechanism, either both may be reduction mechanisms, or either both may be speed increase mechanisms.

[0027] When the first gear ratio is defined as the ratio of the rotational speed after gear shifting (the rotational speed on the side opposite to the motor M in the first gear mechanism T1, i.e., the rotational speed on the motor M side in the first gear mechanism T1, to the rotational speed before gear shifting, and the second gear ratio is defined as the ratio of the rotational speed after gear shifting on the side opposite to the motor M in the second gear mechanism T2, i.e., the rotational speed on the side opposite to the motor M in the second gear mechanism T2, i.e., the rotational speed before gear shifting, it is preferable that the first gear ratio is configured to be smaller than the second gear ratio.

[0028] For example, if the first gear ratio of the first transmission mechanism T1 is less than 1, the rotational speed on the side opposite to the motor M (the side opposite to the first spindle unit SP1) decreases compared to the rotational speed on the motor M side, and the torque increases. If the second gear ratio of the second transmission mechanism T2 is greater than 1, the rotational speed on the side opposite to the motor M (the side opposite to the first spindle unit SP1) increases compared to the rotational speed on the motor M side, and the torque decreases. In this case, the first drive gear 78 has a smaller diameter than the second drive gear 80, and the first drive gear 78 and the motor M can be placed in close proximity. In this embodiment, the first transmission mechanism T1 is positioned closer to the motor M than the second transmission mechanism T2. More specifically, the motor M is positioned in front of the first drive gear 78 and overlaps with the first drive gear 78 in the vertical direction.

[0029] The first transmission mechanism T1 and the second transmission mechanism T2 are switched by an intermittent mechanism 50. The intermittent mechanism 50 includes an upper clutch 50U that switches the disconnection and connection of power in the first transmission mechanism T1, a lower clutch 50D that switches the disconnection and connection of power in the second transmission mechanism T2, and an actuator 55 that rotates integrally with the input gear 77.

[0030] The upper clutch 50U is a meshing clutch comprising a first engaging element 51, which is an engaging element on the motor M side, and a second engaging element 52, which is an engaging element on the first transmission mechanism T1 side. More specifically, the first engaging element 51 is provided above the actuator 55 and the input gear 77 so as to rotate integrally with the input gear 77. The second engaging element 52 is provided below the first drive gear 78 so as to rotate integrally with the first drive gear 78 and be engageable with the first engaging element 51. The second engaging element 52 and the first drive gear 78 are mounted above the second spindle 75 of the second spindle unit SP2 so as to be rotatable relative to the second spindle 75 but immovable.

[0031] The lower clutch 50D is a meshing clutch comprising a third engaging element 53, which is an engaging element on the motor M side, and a fourth engaging element 54, which is an engaging element on the second transmission mechanism T2 side. More specifically, the third engaging element 53 is provided below the actuator 55 and the input gear 77 so as to rotate integrally with the input gear 77. The fourth engaging element 54 is provided above the second drive gear 80 so as to rotate integrally with the second drive gear 80 and be engageable with the third engaging element 53. The fourth engaging element 54 and the second drive gear 80 are mounted below the second spindle 75 of the second spindle unit SP2 so as to be rotatable relative to the second spindle 75 but immovable.

[0032] As described above, the actuator 55 is attached to the input gear 77 so as to rotate together with the input gear 77, and the first engaging element 51 and the third engaging element 53 are attached to its upper and lower parts so as to rotate together. The actuator 55 is interposed between the first drive gear 78 and the second drive gear 80 in the vertical direction, approximately in the center of the second spindle 75. Here, the actuator 55 is the screw nut 76 of the second spindle unit SP2. The second spindle unit SP2 has a second spindle 75 with a male thread formed thereon and a screw nut 76 (actuator 55) with a female thread formed thereon, and as the input gear 77 rotates, the screw nut 76 (actuator 55) rotates along the axis of the second spindle 75 while undergoing translational motion.

[0033] The screw nut 76 (actuator 55) moves upward in the vertical direction, which is the direction of translational motion, when the motor M rotates in the first direction (direction of arrow D1 in Figure 5A), and moves downward in the vertical direction when the motor M rotates in the second direction opposite to the first direction (direction of arrow D2 in Figure 5B). In this way, the direction of movement of the actuator 55 can be changed by changing the direction of rotation of the motor M.

[0034] The intermittent mechanism 50 can take on three states: a first gear shift state, a second gear shift state, and a free state, by the translational motion of the actuator 55 along the axis of the second spindle 75.

[0035] In the first gear shift state, as shown in Figure 5A, the motor M rotates in the first direction (direction of arrow D1 in Figure 5A), and the screw nut 76 (actuator 55) moves upward, causing the first engaging element 51 and the second engaging element 52 to connect and the third engaging element 53 and the fourth engaging element 54 to disconnect. In other words, the upper clutch 50U becomes connected and the lower clutch 50D becomes disconnected. In the first gear shift state, the power of the motor M is transmitted to the output gear 72, input gear 77, actuator 55, first engaging element 51, second engaging element 52, first drive gear 78, first driven gear 79, and first spindle unit SP1.

[0036] In the second gear shift state, as shown in Figure 5B, the motor M rotates in the second direction (direction of arrow D2 in Figure 5B), and the screw nut 76 (actuator 55) moves downward, causing the first engaging element 51 and the second engaging element 52 to disengage and the third engaging element 53 and the fourth engaging element 54 to engage. In other words, the upper clutch 50U becomes disengaged and the lower clutch 50D becomes engaged. In the second gear shift state, the power of the motor M is transmitted to the output gear 72, input gear 77, actuator 55, third engaging element 53, fourth engaging element 54, second drive gear 80, second driven gear 81, and first spindle unit SP1.

[0037] In the free state, as shown in Figure 5C, the first engaging element 51 and the second engaging element 52 are disengaged, and the third engaging element 53 and the fourth engaging element 54 are also disengaged. In other words, both the upper clutch 50U and the lower clutch 50D are disengaged. In the free state, the motor M stops, and the first driven gear 79 and the second driven gear 81 rotate due to the rotation of the first spindle unit SP1. The rotation of the first spindle unit SP1 is transmitted to the first driven gear 79, the first drive gear 78, and the second engaging element 52, but not to the first engaging element 51. Similarly, the rotation of the first spindle unit SP1 is transmitted to the second driven gear 81, the second drive gear 80, and the fourth engaging element 54, but not to the third engaging element 53.

[0038] In Figures 4 to 5C, the symbol D represents a rotary damper, which provides appropriate resistance to the second spindle 75 of the second spindle unit SP2 so that the screw nut 76 (actuator 55) can be reliably translated when the motor M rotates. The rotary damper D consists of a first damper gear 86 provided on the rotation axis of the rotary damper D, and a second damper gear 87 provided on the second spindle 75 of the second spindle unit SP2 so as to rotate integrally with the second spindle 75 and meshing with the first damper gear 86. The rotary damper D is located in front of and above the bottom plate portion 62 of the transmission case 60, and below the motor M.

[0039] With the powered prosthetic leg 1 configured in this way, it becomes possible to smoothly perform the action of climbing stairs, which previously required climbing one step at a time using the non-prosthetic leg (healthy leg) with a passive prosthetic leg equipped with a passive damper.

[0040] To explain in more detail, as shown in Figure 6, when the electric prosthetic leg 1 is extended forward to climb stairs, a large amount of power is required to extend the knee joint mechanism 30 from a flexed position while the electric prosthetic leg 1 is subjected to external weight.

[0041] At this time, as shown in Figure 5A, by rotating the motor M in the first direction (direction of arrow D1 in Figure 5A), the power of the motor M is transmitted from the output gear 72 to the input gear 77. As the input gear 77 rotates in the second direction (direction of arrow D2 in Figure 5A), the actuator 55 rotates around the second spindle 75 of the second spindle unit SP2 and is guided upward by the second spindle 75. Then, the first engaging element 51, which is located above the actuator 55 and the input gear 77, engages with the second engaging element 52, which is located below the first drive gear 78, and the intermittent mechanism 50 enters the first gear shift state.

[0042] When the intermittent mechanism 50 is in the first gear shift state, the power of the motor M is transmitted to the output gear 72, input gear 77, actuator 55, first engaging element 51, second engaging element 52, first drive gear 78, first driven gear 79, and first spindle unit SP1. As the first drive gear 78 rotates together with the input gear 77 in the second direction (direction of arrow D2 in Figure 5A), the first driven gear 79 rotates in the first direction (direction of arrow D1 in Figure 5A), and as the first driven gear 79 rotates in the first direction (direction of arrow D1 in Figure 5A), the first spindle 73 of the first spindle unit SP1 rotates in the first direction (direction of arrow D1 in Figure 5A). As a result, the sleeve 74 moves translationally away from the transmission T, and the upper knee member 20 to which the sleeve 74 is attached rotates around the pivot part 35 relative to the lower knee member 10 to which the transmission T is attached, causing the knee joint mechanism 30 to extend.

[0043] On the other hand, in order to perform the stair-climbing motion smoothly, as shown in Figure 7, the knee joint mechanism 30 needs to be flexed (lifted) from an extended position while external weight is applied to the healthy leg, or in other words, while no external weight is applied to the electric prosthetic leg 1. When flexing the knee joint mechanism 30 from an extended position, a large amount of power is not required, but a quick movement is necessary.

[0044] At this time, as shown in Figure 5B, by rotating the motor M in the second direction (direction of arrow D2 in Figure 5B), the power of the motor M is transmitted from the output gear 72 to the input gear 77. As the input gear 77 rotates in the first direction (direction of arrow D1 in Figure 5B), the actuator 55 rotates around the second spindle 75 of the second spindle unit SP2 and is guided downward by the second spindle 75. Then, the third engaging element 53, located below the actuator 55 and the input gear 77, engages with the fourth engaging element 54, located above the second drive gear 80, and the intermittent mechanism 50 enters the second gear shift state.

[0045] When the intermittent mechanism 50 is in the second gear shift state, the power of the motor M is transmitted to the output gear 72, input gear 77, actuator 55, third engaging element 53, fourth engaging element 54, second drive gear 80, second driven gear 81, and first spindle unit SP1. As the second drive gear 80 rotates together with the input gear 77 in the first direction (direction of arrow D1 in Figure 5B), the second driven gear 81 rotates in the second direction (direction of arrow D2 in Figure 5B), and as the second driven gear 81 rotates in the second direction (direction of arrow D2 in Figure 5B), the first spindle 73 of the first spindle unit SP1 rotates in the second direction (direction of arrow D2 in Figure 5B). As a result, the sleeve 74 moves in translation so as to move closer to the transmission T, and the lower knee member 10 to which the transmission T is attached rotates around the pivot part 35 relative to the upper knee member 20 to which the sleeve 74 is attached, causing the knee joint mechanism 30 to flex.

[0046] Furthermore, by setting the intermittent mechanism 50 to a free state during normal walking, power transmission between the motor M and the transmission T can be interrupted, preventing it from interfering with walking.

[0047] In the electrically powered prosthetic leg 1 configured in this way, the knee joint mechanism 30 can be extended and flexed via a transmission T that transmits power from the motor M. The motor M is controlled by a control system 100, which will be described later. The rotation range of the knee joint mechanism 30 is limited to 180° or less. When the knee joint mechanism 30 is extended, the angle between the lower knee member 10 and the upper knee member 20 is approximately 180°, and when the knee joint mechanism 30 is flexed, this angle is less than 180°.

[0048] The transmission T is equipped with two power transmission paths with different gear ratios, allowing it to switch between extension and flexion movement speeds and generated power in the knee joint mechanism 30. In particular, when climbing stairs, the required movement speed and generated power differ between flexion and extension of the knee joint mechanism 30, and the power transmission path can be changed for flexion and extension of the knee joint mechanism 30.

[0049] Furthermore, the intermittent mechanism 50 interposed between the motor M and the transmission T includes an upper clutch 50U interposed between the motor M and the first transmission mechanism T1, and a lower clutch 50D interposed between the motor M and the second transmission mechanism T2, so that the two power transmission paths can be appropriately switched.

[0050] In particular, the telescopic device 40 is equipped with a second spindle unit SP2 that converts the rotational power output from the motor M into the translational motion of the actuator 55, so that one motor M can control both the actuator 55 and the extension and flexion of the knee joint mechanism 30. Furthermore, since one actuator 55 can switch the transmission T between a first geared state, a second geared state, and a free state, it is possible to avoid the simultaneous connection of two power transmission paths.

[0051] Furthermore, when the knee joint mechanism 30 is in an extended state, and the electric prosthesis 1 is viewed along the rotation axis of the rotating part 35 of the knee joint mechanism 30, the region where the angle between the lower knee member 10 and the upper knee member 20 is less than 180° (the region posterior (calf) to the line connecting the rotating part 35 and the lower oscillating part 70 in Figure 3) is called the narrow-angle region (the region posterior (calf) to the line connecting the rotating part 35 and the lower oscillating part 70 in Figure 3), and the region where the angle is 180° or more (the region anterior (shin) to the line connecting the rotating part 35 and the lower oscillating part 70 in Figure 3) is called the wide-angle region (the region anterior (shin) to the line connecting the rotating part 35 and the lower oscillating part 70 in Figure 3), then the first spindle unit SP1 is positioned in the narrow-angle region. On the other hand, the motor M is positioned in the wide-angle region. By positioning the first spindle unit SP1 in a narrow-angle region and the motor M in a wide-angle region, the first spindle unit SP1 and the motor M can be positioned in a balanced manner with the rotating part 35 of the knee joint mechanism 30 in between. Furthermore, the transmission T and the intermittent mechanism 50 are positioned between the motor M and the first spindle unit SP1. Therefore, the motor M, transmission T, intermittent mechanism 50 and the first spindle unit SP1 can be positioned in a concentrated manner.

[0052] <Second Embodiment> The second embodiment of the electric prosthesis 1 differs from the first embodiment in the configuration of the telescopic device 40. More specifically, in the first embodiment of the telescopic device 40, the translational motion of the actuator 55 was achieved by the conversion of rotational power output from the motor M by the second spindle unit SP2. In contrast, in the second embodiment of the telescopic device 40, the translational motion of the actuator 55 is achieved by a clutch actuator ACT, which is a different drive source from the motor M, and a clutch fork 90 that transmits the power of the clutch actuator ACT to the actuator 55. In the following description, the telescopic device 40 of the second embodiment of the electric prosthesis 1 will be described with reference to Figures 8 and 9. Components that are the same as or equivalent to those of the first embodiment of the electric prosthesis 1 will be denoted by the same reference numerals in the figures and their descriptions will be omitted, with only the differences being described.

[0053] As shown in Figures 8 and 9, the telescopic device 40 of the second embodiment includes a motor M that outputs rotational power, a transmission T that transmits power from the motor M, a first spindle unit SP1 that is connected to the transmission T in a power-transmitting manner and converts the rotational power output from the transmission T into translational motion, an intermittent mechanism 50 interposed between the motor M and the first transmission mechanism T1 and the second transmission mechanism T2 of the transmission T, a support shaft 95 that is arranged parallel to the output shaft 71 of the motor M and the first spindle 73 of the first spindle unit SP1 and supports the intermittent mechanism 50, a clutch actuator ACT that performs translational motion, and a clutch fork 90 that transmits power from the clutch actuator ACT to the actuator 55 of the intermittent mechanism 50.

[0054] The clutch actuator ACT is a different power source from the motor M, and as shown by arrow Y1 in Figure 8, it performs translational motion along the axial direction (vertical direction) of the support shaft 95.

[0055] The clutch fork 90 is configured to swing freely around the pivot shaft 65, as shown by arrow Y2 in Figure 8, with one end of the clutch fork 90 connected to the clutch actuator ACT and the middle part supported by the pivot shaft 65. At the other end of the clutch fork 90, two arms 92 are provided, branching out from a branching section 91 located on the opposite side of the pivot shaft 65 from the clutch actuator ACT, and extending in opposite directions in an arc shape. At the tip of each arm 92, a connecting pin 93 is provided, which engages with the slide clutch 56 described later. Therefore, when the clutch actuator ACT performs translational motion, the clutch fork 90 swings around the pivot shaft 65, and the connecting pins 93 of the clutch fork 90 swing up and down.

[0056] The transmission T comprises an output gear 72 provided on the output shaft 71 of the motor M, a first input gear 77A and a second input gear 77B provided approximately in the center of the support shaft 95 and meshing with the output gear 72, a first transmission mechanism T1, and a second transmission mechanism T2. The first input gear 77A and the second input gear 77B constitute the input gear 77.

[0057] The first gear shift mechanism T1 consists of a first drive gear 78 that is immovably mounted on the upper side of the support shaft 95, and a first driven gear 79 that is mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshes with the first drive gear 78.

[0058] The second transmission mechanism T2 consists of a second drive gear 80 fixedly mounted on the lower side of the support shaft 95, and a second driven gear 81 mounted on the first spindle 73 of the first spindle unit SP1 so as to rotate integrally with the first spindle 73 and meshing with the second drive gear 80.

[0059] Note that the gear ratios of the first transmission mechanism T1 and the second transmission mechanism T2 are the same as in the first embodiment, so their explanation is omitted here. The first transmission mechanism T1 and the second transmission mechanism T2 are switched by an intermittent mechanism 50. The intermittent mechanism 50 comprises an upper clutch 50U interposed between the motor M and the first transmission mechanism T1, a lower clutch 50D interposed between the motor M and the second transmission mechanism T2, and an actuator 55.

[0060] The upper clutch 50U is a meshing clutch comprising a first engaging element 51, which is an engaging element on the motor M side, and a second engaging element 52, which is an engaging element on the first transmission mechanism T1 side. More specifically, the first engaging element 51 is provided above the first input gear 77A so as to rotate integrally with the first input gear 77A. The second engaging element 52 is provided below the first drive gear 78 so as to rotate integrally with the first drive gear 78 and be engageable with the first engaging element 51. The second engaging element 52 and the first drive gear 78 are mounted above the support shaft 95 so as to be rotatable relative to the support shaft 95 but immovable.

[0061] The lower clutch 50D is a meshing clutch comprising a third engaging element 53, which is an engaging element on the motor M side, and a fourth engaging element 54, which is an engaging element on the second transmission mechanism T2 side. More specifically, the third engaging element 53 is provided below the second input gear 77B so as to rotate integrally with the second input gear 77B. The fourth engaging element 54 is provided above the second drive gear 80 so as to rotate integrally with the second drive gear 80 and be engageable with the third engaging element 53. The fourth engaging element 54 and the second drive gear 80 are mounted below the support shaft 95 so as to be rotatable relative to the support shaft 95 but immovable.

[0062] The actuator 55 comprises an annular slide clutch 56 that is constantly engaged with the connecting pin 93 of the clutch fork 90, and a bearing 57 that performs translational motion together with the slide clutch 56, and is positioned vertically between the first input gear 77A and the second input gear 77B.

[0063] The slide clutch 56 is provided with a connecting hole into which the connecting pin 93 of the clutch fork 90 engages. The connecting hole absorbs the oscillation of the clutch fork 90 and converts it into vertical translational motion of the slide clutch 56.

[0064] The bearing 57 comprises an outer ring 57a that is non-rotatably supported by the slide clutch 56, an inner ring 57b configured to rotate integrally with a first input gear 77A provided with a first engaging element 51 and a second input gear 77B provided with a third engaging element 53, and rolling elements 57c disposed between the outer ring 57a and the inner ring 57b, allowing relative rotation between the outer ring 57a and the inner ring 57b.

[0065] The inner ring 57b is supported on the outer circumference of a support flange 96, which is key-connected to the support shaft 95 together with the first input gear 77A and the second input gear 77B, so as to be able to move translationally in the vertical direction.

[0066] The slide clutch 56 and bearing 57 (actuator 55) move upward along the support shaft 95 when one end of the clutch fork 90 moves downward by the clutch actuator ACT, and move downward along the support shaft 95 when one end of the clutch fork 90 moves upward by the clutch actuator ACT. A predetermined vertical gap is provided between the slide clutch 56 and outer ring 57a and the first input gear 77A, so that the first input gear 77A does not interfere with the slide clutch 56 and outer ring 57a, which are non-rotating members. Similarly, a predetermined vertical gap is provided between the slide clutch 56 and outer ring 57a and the second input gear 77B, so that the second input gear 77B does not interfere with the slide clutch 56 and outer ring 57a, which are non-rotating members.

[0067] The intermittent mechanism 50 can take on three states: a first gear shift state, a second gear shift state, and a free state, by having the slide clutch 56 and bearing 57 (actuator 55) translate vertically along the axis of the support shaft 95.

[0068] In the first gear shift state, the slide clutch 56 and bearing 57 (actuator 55) move upward, so that the first engaging element 51 and the second engaging element 52 are engaged and the third engaging element 53 and the fourth engaging element 54 are disengaged, as in Figure 5A. In other words, the upper clutch 50U is engaged and the lower clutch 50D is disengaged. In the first gear shift state, the power of the motor M is transmitted to the output gear 72, the first input gear 77A (inner ring 57b and second input gear 77B), the first engaging element 51, the second engaging element 52, the first drive gear 78, the first driven gear 79, and the first spindle unit SP1.

[0069] In the second gear shift state, the slide clutch 56 and bearing 57 (actuator 55) move downward, so that the first engaging element 51 and the second engaging element 52 are disengaged and the third engaging element 53 and the fourth engaging element 54 are engaged, similar to Figure 5B. In other words, the upper clutch 50U is disengaged and the lower clutch 50D is engaged. In the second gear shift state, the power of the motor M is transmitted to the output gear 72, the second input gear 77B (inner ring 57b and first input gear 77A), the third engaging element 53, the fourth engaging element 54, the second drive gear 80, the second driven gear 81, and the first spindle unit SP1.

[0070] In the free state, as in Figure 5C, the first engaging element 51 and the second engaging element 52 are disengaged, and the third engaging element 53 and the fourth engaging element 54 are also disengaged. In other words, the upper clutch 50U is disengaged, and the lower clutch 50D is disengaged. In the free state, the motor M stops, and the first driven gear 79 and the second driven gear 81 rotate due to the rotation of the first spindle unit SP1. The rotation of the first spindle unit SP1 is transmitted to the first driven gear 79, the first drive gear 78, and the second engaging element 52, but not to the first engaging element 51. Similarly, the rotation of the first spindle unit SP1 is transmitted to the second driven gear 81, the second drive gear 80, and the fourth engaging element 54, but not to the third engaging element 53.

[0071] In the electric prosthesis 1 configured in this way, the knee joint mechanism 30 can be extended and flexed via a transmission T that transmits power from the motor M, similar to the first embodiment, and the effects described in the electric prosthesis 1 of the first embodiment can be obtained. Furthermore, in the electric prosthesis 1 of the second embodiment, the actuator 55 is switched using a clutch actuator ACT, which is a different power source from the motor M used to extend and flex the knee joint mechanism 30, so that the actuator 55 can be switched more stably.

[0072] <Step-up control> Next, we will explain the control of climbing stairs using the electric prosthetic leg 1 of the first and second embodiments described above, using the electric prosthetic leg 1 of the second embodiment as an example. In the following explanation, the leg that is not bearing external weight, in other words, the leg that is not supporting body weight, will be referred to as the "swing leg," and the leg that is bearing external weight, in other words, the leg that is supporting body weight, will be referred to as the "standing leg." Note that the electric prosthetic leg 1 is always subjected to its own weight due to gravity (self-weight), but this self-weight is not included in the external weight.

[0073] [Example 1] As shown in Figures 10 and 11, the electric prosthesis 1 includes a load / load sensor 201, which is a load sensor, located at the lower part of the lower leg member 10 (for example, the leg portion 11), a shin IMU (Inertial Measurement Unit) 203, which is a posture sensor located on the lower leg member 10 and capable of detecting the angle of the lower leg member 10 relative to the ground (angle relative to the ground), and the lower leg member 10 and the upper leg member 20. A knee angle sensor 205, which is a rotation angle sensor that detects the angle, is provided.

[0074] The control system 100 of the electric prosthesis 1 includes a load / relief acquisition unit 102 that acquires the load FZ applied to the lower leg member 10, a knee angle calculation unit 103 that acquires the knee angle θ, which is the angle between the center line CL5 of the lower leg 5 and the center line CL4 of the thigh 4, a hip joint torque calculation unit 104 that calculates the hip joint torque MYh that acts on the hip joint 7 due to the load FZ applied to the lower leg member 10, a thigh angle calculation unit 106 that calculates the thigh angle β, which is the angle of the thigh 4 with respect to a virtual line LN extending vertically through the hip joint 7, a motor control unit 108 that controls the motor M, and an intermittent mechanism control unit 110 that controls the state of the intermittent mechanism 50. Note that in the first embodiment, the motor control unit 108 also serves as the intermittent mechanism control unit 110.

[0075] The load / release unit 102 acquires the load FZ, which is the axial force applied to the lower knee member 10, from the load / release sensor 201. The load FZ applied to the lower knee member 10 may be the detected value from the load / release sensor 201 or a predicted value. In this embodiment, the positive direction is defined as when the load FZ applied to the lower knee member 10 is in the tensile direction.

[0076] The knee angle calculation unit 103 obtains the knee angle θ by subtracting the angle detected by the knee angle sensor 205 from 180°. The knee angle θ is defined as 0° when the center line CL5 of the lower leg 5 and the center line CL4 of the thigh 4 coincide, and increases in the positive direction as the knee joint mechanism 30 flexes.

[0077] The hip joint torque calculation unit 104 calculates the hip joint torque MYh by multiplying the load FZ applied to the lower leg member 10 by the distance from the center line CL5 of the lower leg 5 to the hip joint 7 (length of the thigh 4). If the length of the user's thigh 4 is L and the knee angle is θ, the hip joint torque MYh is given by the following equation (1). The positive direction for the hip joint torque MYh is when the hip joint 7 is rotated forward (clockwise in Figure 11). It is preferable that the length L of the thigh 4 is pre-registered in a memory (not shown) and can be rewritten according to the user.

[0078] MYh = FZ × L × sinθ (1)

[0079] The thigh angle calculation unit 106 calculates the thigh angle β based on the output values ​​of the shin IMU 203 and the knee angle sensor 205. The thigh angle β is a positive value when the thigh 4 is posterior to the virtual line LN extending vertically through the hip joint 7, and a negative value when the thigh 4 is anterior to the virtual line LN.

[0080] The motor control unit 108 controls the drive / stop of motor M and the output when motor M is driven. Step-up control will be described later.

[0081] The intermittent mechanism control unit 110 switches the actuator 55 based on the load FZ acquired by the load / release acquisition unit 102, thereby switching the intermittent mechanism 50 between the first shift state, the second shift state, and the free state described above.

[0082] To explain in more detail, when the intermittent mechanism control unit 110 acquires that the load / removal acquisition unit 102 has transitioned from a state where no load is applied to a state where a load is applied, or when it predicts such a transition, in other words, when the electric prosthesis 1 has transitioned from the swing leg to the stance leg, or when it predicts such a transition, it switches the upper clutch 50U of the intermittent mechanism 50, which is one of the upper clutch 50U and lower clutch 50D, to the connected state, thereby setting it to the first gear shift state. This makes it possible to transmit power via the first gear shift mechanism T1, which has a small gear ratio, during the stance leg when the knee joint mechanism 30 extends from a flexed state, and allows for the transmission of a large amount of power to the electric prosthesis 1 when it is externally loaded.

[0083] On the other hand, when the load / load acquisition unit 102 acquires that the load has transitioned from a loaded state to an unloaded state, or when it predicts such a transition, in other words, when the electric prosthesis 1 transitions from the stance leg to the swing leg, or when it predicts such a transition, the intermittent mechanism control unit 110 switches the lower clutch 50D of the intermittent mechanism 50, which is one of the upper clutch 50U and lower clutch 50D, to the connected state, thereby setting it to the second gear shift state. This makes it possible to transmit power via the second gear shift mechanism T2, which has a large gear ratio, when the knee joint mechanism 30 is flexed from an extended state to the swing leg, allowing the knee joint mechanism 30 to be quickly flexed when the electric prosthesis 1 is not subjected to external load.

[0084] The control system 100 may also include a direction acquisition unit that acquires the direction of movement of the user of the electric prosthetic leg 1. When the direction acquisition unit detects an angular velocity moving vertically upward, such as when climbing steps or going uphill, from the value detected by the shin IMU 203, it may perform step-up control, or it may perform step-up control based on the user's input.

[0085] The following describes the control flow for the first example of rank advancement control. As shown in Figure 12, the control system 100 performs a stance / swing phase determination process (S1) in the step-up control to determine whether the electric prosthesis 1 is in the stance phase or the swing phase. Specifically, the control system 100 performs the stance / swing phase determination based on the load FZ acquired by the load / load acquisition unit 102. As described above, the positive direction is defined as when the load FZ applied to the lower knee member 10 is in the tensile direction. Therefore, when the electric prosthesis 1 is in the swing phase, the load FZ takes on a positive value due to the weight of the electric prosthesis 1. From there, when the electric prosthesis 1 lands and is loaded in the compressive direction, the load FZ approaches zero, and as the load increases further, it takes on a negative value.

[0086] Figure 14 is a graph showing the load FZ and hip joint torque MYh during stair climbing. In the upper graph of Figure 14, the vertical axis represents the load FZ (N), and in the lower graph of Figure 14, the vertical axis represents the hip joint torque MYh (N·m). In both the upper and lower graphs of Figure 14, the horizontal axis represents time (s).

[0087] Referring to Figures 12 and 14, the control system 100 determines whether the load FZ is less than or equal to the threshold T11(N), which is the value between 0(N) and the value when only the body weight acts on the electric prosthesis 1 (S1). When the load FZ is less than or equal to this threshold T11 (YES in S1), it is determined that the electric prosthesis 1 is in the stance phase (S2). On the other hand, when the load FZ is greater than this threshold T11 (NO in step S1), it is determined that the electric prosthesis 1 is in the swing phase (S7). Note that the determination of stance phase and swing phase may also be made based on user input. User input can be any means, such as a switch, button, or voice.

[0088] When the electric prosthesis 1 is in the stance position, the hip joint torque calculation unit 104 calculates the hip joint torque MYh acting on the hip joint 7 based on the applied load FZ (S3). When the electric prosthesis 1 is loaded in the compressive direction, a hip joint torque is generated that causes the hip joint 7 to rotate backward (counterclockwise in Figure 11). The hip joint torque calculation unit 104 obtains the hip joint torque MYh from equation (1) based on the knee angle θ formed by the angle between the lower knee member 10 and the upper knee member 20, the length L of the thigh 4, and the applied load FZ obtained by the load / removal acquisition unit 102.

[0089] When the calculated hip joint torque MYh is 0 (N·m) or less (YES in S4), that is, when a torque is acting in a direction that rotates the hip joint 7 backward (counterclockwise in Figure 11) due to the load (early stance phase), the motor control unit 108 controls the motor M with current control, using a torque in the opposite direction with the same magnitude as the hip joint torque MYh as the control target, as shown by the dotted line in the lower graph of Figure 14. As a result, the motor torque and the hip joint torque MYh are balanced, and the knee joint mechanism 30 can be extended (S5). In this way, by controlling the motor torque generated from the motor M based on the hip joint torque calculated by the hip joint torque calculation unit 104, the motor torque for extension can be appropriately set.

[0090] On the other hand, when the calculated hip joint torque MYh is greater than zero (NO in S4), that is, when a torque is acting in a direction that rotates the hip joint 7 forward (counterclockwise in Figure 11) due to the load (mid to late stance phase), the motor M is stopped as shown in Figure 14 (S6). Even when the motor M is stopped, the connection of the upper clutch 50U in the first gear shift state is maintained, so that sliding resistance acts on the knee joint mechanism 30.

[0091] When the electric prosthetic leg 1 is in the swing phase, as shown in Figure 13, the control system 100 determines whether the thigh angle β is greater than or equal to the threshold θh1 (θh1 is negative) for the thigh angle β that separates the early swing phase from the late swing phase (S8). If the thigh angle β is greater than the threshold θh1 (YES in S8), it is determined to be the early swing phase, that is, the situation in which the user swings up the thigh 4 and flexes the knee joint mechanism 30 (S9). In this early swing phase, it is then determined whether the thigh angle β is 0° or greater (S10), and if the thigh angle β is 0° or greater (YES in S10), the motor M is controlled by current until the thigh angle β becomes less than 0°, with the target knee angle θ (hereinafter referred to as the target knee angle) being θk1 (a positive value) (S11).

[0092] If the thigh angle β is less than 0° in step S10 (NO in S10), the motor M is controlled by current using the value obtained by multiplying the thigh angle β by -1 and adding θk1 as the target knee angle (S12). A in Figure 13 is a graph showing the target knee angle in steps S11 and S12.

[0093] On the other hand, in step S8, if the thigh angle β is less than or equal to the threshold θh1 (NO in S8), and if the knee joint mechanism 30 flexes from step S12 and the thigh angle β becomes less than or equal to the threshold θh1 (YES in S14), it is determined that this is the late swing phase, i.e., the situation in which the knee joint mechanism 30 extends when the user lowers the thigh 4 (S13). In this late swing phase, it is then determined whether the thigh angle β is less than or equal to the threshold θh2 (θh2 is negative and θh2 > θh1) (S15). If the thigh angle β is less than θh2 (YES in S15), the target knee angle is set to the value obtained by multiplying the thigh angle β by minus 1 and adding θh2, and the motor M is controlled by current until the thigh angle β is greater than or equal to θh2 (S16). In step S15, if the thigh angle β is greater than or equal to θh2 (NO in S15), the target knee angle is set to 0° and the motor M is controlled by current (S17). In Figure 13, B is a graph showing the target knee angle in steps S16 and S17. It is preferable that the motor control unit 108 performs feedback control in steps S11, S12, S16, and S17 based on the knee angle θ and the target knee angle obtained by the knee angle calculation unit 103.

[0094] [Example 2] As shown in Figures 15 and 16, the electric prosthesis 1 used for the second example of step-up control is equipped with a force sensor 207 instead of the aforementioned load / relief sensor 201. That is, the electric prosthesis 1 of the second example is equipped with a shin IMU 203, a knee angle sensor 205, and a force sensor 207. As shown in Figure 16, the force sensor 207 is configured to detect at least the load FZ2, which is the axial force applied to the thigh 4, the knee shear force FXk, which acts in a direction perpendicular to the load FZ2, and the knee torque MYk, which is the rotational force around the rotating part 35 of the knee joint mechanism 30.

[0095] The control system 100 of the electric prosthetic leg 1 includes a load / relief acquisition unit 102 that acquires the load FZ applied to the lower leg member 10, a knee angle calculation unit 103 that acquires the knee angle θ, which is the angle between the center line CL5 of the lower leg 5 and the center line CL4 of the thigh 4, a thigh angle calculation unit 106 that calculates the thigh angle β, which is the angle of the thigh 4 with respect to a virtual line LN extending vertically through the hip joint 7, a thigh load acquisition unit 112 that acquires the load FZ2 applied to the thigh 4, a knee torque acquisition unit 113 that acquires the knee torque MYk, a knee shear force acquisition unit 114 that acquires the knee shear force FXk applied to the thigh 4, a hip joint torque calculation unit 104 that calculates the hip joint torque MYh acting on the hip joint 7 based on the knee torque MYk and the knee shear force FXk, a motor control unit 108 that controls the motor M, and an intermittent mechanism control unit 110 that controls the state of the intermittent mechanism 50.

[0096] The load / load acquisition unit 102, knee angle calculation unit 103, thigh angle calculation unit 106, and motor control unit 108 are the same as in the first example, so their explanation will be omitted.

[0097] The thigh load acquisition unit 112, the knee torque acquisition unit 113, and the knee shear force acquisition unit 114 acquire the load FZ2, knee torque MYk, and knee shear force FXk from the force sensor 207, respectively. In this embodiment, the positive direction is defined as when the load FZ2 applied to the thigh 6 is in the compression direction.

[0098] The hip joint torque calculation unit 104 calculates the hip joint torque MYh by adding to the knee torque MYk a value obtained by multiplying the length L of the thigh 4 by the knee shear force FXk. In this example, the hip joint torque MYh is given by the following equation (2). The positive direction for the hip joint torque MYh is when the hip joint 7 is rotated forward (clockwise in Figure 16).

[0099] MYh = MYk + L × FXk (2)

[0100] The intermittent mechanism control unit 110 switches the intermittent mechanism 50 to the first shift state, second shift state, and free state described above, based on the load FZ2 acquired by the thigh load acquisition unit 112.

[0101] To explain in more detail, when the thigh load acquisition unit 112 acquires or predicts that it has transitioned from a state where no external load is being applied to a state where an external load is being applied, in other words, when the electric prosthesis 1 transitions from the swing phase to the stance phase, or when the transition is predicted, the upper clutch 50U of the intermittent mechanism 50, which consists of the upper clutch 50U and lower clutch 50D, is switched to the connected state, setting it to the first gear shift state. This makes it possible to transmit power via the first gear shift mechanism T1 with a small gear ratio during the stance phase when the knee joint mechanism 30 extends from a flexed state, and to transmit a large amount of power to the electric prosthesis 1 when it is under external load.

[0102] On the other hand, when the thigh load acquisition unit 112 acquires that it has transitioned from a state where it is externally loaded to a state where it is not externally loaded, or when it predicts such a transition, in other words, when the electric prosthesis 1 transitions from the stance phase to the swing phase, or when it predicts such a transition, the lower clutch 50D of the intermittent mechanism 50, of which the upper clutch 50U and lower clutch 50D are connected, is switched to the second gear shift state. This makes it possible to transmit power via the second gear shift mechanism T2, which has a large gear ratio, when the knee joint mechanism 30 is flexed from an extended state to the swing phase, allowing the knee joint mechanism 30 to be quickly flexed when the electric prosthesis 1 is not externally loaded.

[0103] Incidentally, it is the same as the first example in that the control system 100 may include a traveling direction acquisition unit that acquires the traveling direction of the user of the prosthetic leg 1.

[0104] Hereinafter, the control flow of the ascending step control in the second example will be described. As shown in FIG. 17, in the ascending step control, the control system 100 performs a landing determination to determine whether or not the prosthetic leg 1 has landed (S21). Specifically, the control system 100 performs the landing determination based on the load FZ2 acquired by the thigh part load acquisition unit 112. When the prosthetic leg 1 is a swing leg, the load FZ2 takes a positive value due to the self-weight of the prosthetic leg 1 (the component force of the load FZ). Therefore, when the prosthetic leg 1 lands and is loaded in the compression direction, the load FZ2 approaches zero, and when the load further increases, it takes a negative value.

[0105] FIG. 19 is a graph showing the load FZ2 and the hip joint torque MYh during ascending the stairs. The vertical axis of the upper graph in FIG. 19 indicates the load FZ2 (N), the vertical axis of the lower graph in FIG. 19 indicates the hip joint torque MYh (N·m), and the horizontal axes of the upper graph and the lower graph in FIG. 19 indicate the time (s).

[0106] Referring to FIGS. 17 and 19, when -T12 < FZ2 < T12, which is an area where the behavior of the load FZ2 is unstable with 0 (N) in between, the control system 100 does not determine whether the prosthetic leg 1 is a stance leg or a swing leg and stops the motor M (S22). When the load FZ2 is greater than or equal to the upper threshold value T12, it is determined that the prosthetic leg 1 is a swing leg (S23). Since the control flow when the prosthetic leg 1 is a swing leg is the same as that in the first example, the description is omitted here.

[0107] When the load FZ2 is less than or equal to the lower threshold value -T12, it is determined that the prosthetic leg 1 has landed and the prosthetic leg 1 is a stance leg (S24). Incidentally, the landing determination may be made based on the input of the user.

[0108] When the electric prosthesis 1 is in the stance position, the hip joint torque calculation unit 104 calculates the hip joint torque MYh acting on the hip joint 7 based on the knee torque MYk and the knee shear force FXk (S25). The hip joint torque calculation unit 104 obtains the hip joint torque MYh from equation (2) by adding the knee shear force FXk, the length L of the thigh 4, and the knee torque MYk.

[0109] Next, the motor control unit 108 calculates the motor voltage (S26). The motor voltage is obtained from an equation based on the hip joint torque MYh, a map showing the relationship between the hip joint torque MYh and the motor voltage, etc. That is, the motor control unit 108 can appropriately set the motor torque for extension by setting the motor voltage based on the hip joint torque calculated by the hip joint torque calculation unit 104 and controlling the motor torque generated from the motor M.

[0110] When the hip joint torque MYh is less than the threshold -M1 (S27), that is, when a torque is acting in a direction that rotates the hip joint 7 backward (counterclockwise in Figure 16), if the knee angle θ is greater than or equal to the threshold θk2 (S28, region AR1 in Figure 18), the motor voltage calculated in step S26 is applied (S29). This balances the motor torque and the hip joint torque MYh, allowing the knee joint mechanism 30 to extend. The threshold θk2 is a critical value to avoid contact between mechanical elements inside the extension / retraction device 40.

[0111] When the hip joint torque MYh is less than the threshold -M1 (S27), that is, when a torque is acting in a direction that rotates the hip joint 7 backward (counterclockwise in Figure 16), if the knee angle θ is less than the threshold θk2 (S30, region AR3 in Figure 18), the motor M is stopped (S31). This prevents contact between mechanical elements inside the telescopic device 40.

[0112] When the hip joint torque MYh is greater than the threshold M1 (S31), that is, when a torque is acting in a direction that rotates the hip joint 7 forward (clockwise in Figure 16), if the knee angle θ is less than or equal to the threshold θk3 (θk3 > θk2) (S32, region AR2 in Figure 18), the motor voltage calculated in step S26 is applied (S33). This balances the motor torque and the hip joint torque MYh, allowing the knee joint mechanism 30 to be flexed. The threshold θk3 is a critical value for avoiding contact between mechanical elements inside the telescopic device 40, and is a critical value in the opposite direction to that of step 30.

[0113] When the hip joint torque MYh is greater than the threshold M1 (S31), that is, when a torque is acting in a direction that rotates the hip joint 7 forward (clockwise in Figure 16), if the knee angle θ is greater than the threshold θk3 (S34, region AR3 in Figure 18), the motor M is stopped (S35). This prevents contact between mechanical elements inside the telescopic device 40.

[0114] When the hip joint torque MYh is greater than or equal to threshold -M1 and less than or equal to threshold M1 (S36, region AR4 in Figure 18), the motor M is stopped (S37). At this time, even if the motor M is stopped, the connection of the upper clutch 50U in the first shift state is maintained, so that sliding resistance acts on the knee joint mechanism 30. In the case of the electric prosthesis 1 of the first embodiment, it is preferable to apply a smaller voltage than in steps S29 and S33 in order to maintain the connection of the upper clutch 50U.

[0115] In the second example, during landing detection (S21), if the behavior of the load FZ2 is in an unstable range, the motor M of the electric prosthesis 1 stops without determining whether it is in the stance or swing phase (S22). Similarly, if the behavior of the hip joint torque MYh is in an unstable range, the motor M of the knee joint mechanism 30 stops without extending or flexing (S37). This prevents the motor M from being driven in situations unintended by the user.

[0116] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

[0117] For example, the above embodiment illustrates an electric prosthetic leg as one embodiment of the joint device of the present invention, but it is not limited to this and may be applied to the upper limb (arm joint), and the wearer may be an animal other than a human, or a robot.

[0118] Furthermore, in the above embodiment, the power of one motor M is transmitted to the first transmission mechanism T1 and the second transmission mechanism T2 via the intermittent mechanism 50. However, the system is not limited to this configuration, and intermittent mechanisms may be provided between the two power sources and the first transmission mechanism T1 and the second transmission mechanism T2.

[0119] Furthermore, it is not necessary for both the first gear shift mechanism T1 and the second gear shift mechanism T2 to be provided; it is sufficient if only one of them is provided.

[0120] Furthermore, the intermittent mechanism 50 is not limited to a meshing clutch, but may also be other clutch mechanisms such as a friction clutch or a centrifugal clutch, or a clutchless mechanism such as a continuous gear ratio switching mechanism.

[0121] Furthermore, this specification includes at least the following information. Note that the components etc. in parentheses indicate those corresponding to the embodiments described above, but are not limited thereto.

[0122] (1) First member (below-knee member 10), The second member (upper knee member 20), A connecting portion (knee joint mechanism 30) that connects the first member and the second member in a way that allows the angle between them to be changed, A joint device (electric prosthetic leg 1) comprising an expandable / contractable device (expandable / contractable device 40) capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source (motor M), It comprises a power transmission unit (transmission T) that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path (first gear mechanism T1) that transmits the aforementioned power at a first gear ratio, The system includes a second power transmission path (second transmission mechanism T2) that transmits the power at a second gear ratio different from the first gear ratio, The aforementioned expandable device is A first intermittent mechanism (upper clutch 50U) for switching the interruption and connection of power in the first power transmission path, The system includes a second intermittent mechanism (lower clutch 50D) for switching between interrupting and connecting power in the second power transmission path, The aforementioned joint device is The power source and the control units (motor control unit 108, intermittent mechanism control unit 110) that control the first intermittent mechanism and the second intermittent mechanism, The device further includes a load acquisition unit (load / relief acquisition unit 102, thigh load acquisition unit 112) that acquires the load (load FZ, load FZ2) applied to the aforementioned joint device, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the load acquired by the load acquisition unit.

[0123] According to (1), the connecting section can be extended and bent via a power transmission section that transmits power from a power source. Furthermore, since the power transmission section is equipped with two power transmission paths with different gear ratios, the operating speed and power generated for extension and bending of the connecting section can be switched.

[0124] Furthermore, the first and second intermittent mechanisms allow for appropriate switching between the two power transmission paths.

[0125] Furthermore, by controlling at least one of the first and second intermittent mechanisms based on the load applied to the joint device, the connecting portion can be extended or bent by power from a drive source.

[0126] (2) The joint device described in (1), The coupling device wherein the control unit, when it obtains that the load acquisition unit has transitioned from a state where no load is applied to a state where a load is applied, switches either the first intermittent mechanism or the second intermittent mechanism to a connected state.

[0127] According to (2), by switching either the first intermittent mechanism or the second intermittent mechanism to a connected state during the transition, the connecting portion can be smoothly extended or bent.

[0128] (3) A coupling device as described in (1) or (2), The power source and the control units (motor control unit 108, intermittent mechanism control unit 110) that control the first intermittent mechanism and the second intermittent mechanism, The device further comprises a direction acquisition unit that acquires the direction of travel of the main body to which the coupling device is attached, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired by the direction of travel acquisition unit.

[0129] According to (3), by determining whether the joint is moving upward or downward, it is possible to appropriately determine the situation in which the connecting section is extended and the situation in which it is bent.

[0130] (4) The joint device described in (3), The first gear ratio is defined as the ratio of the rotational speed after gear shifting to the rotational speed before gear shifting, which is the rotational speed on the power source side in the first power transmission path. When the second gear ratio is defined as the ratio of the rotational speed after gear shifting to the rotational speed before gear shifting, which is the rotational speed on the power source side in the second power transmission path, The first gear ratio is configured to be smaller than the second gear ratio. The control unit connects the first intermittent mechanism when it detects that the mounting body is moving vertically upward.

[0131] According to (4), a large amount of power can be generated by engaging the first transmission path with a small gear ratio when going uphill.

[0132] (5) The joint device described in (4), The second member is configured to be attachable to the first part (thigh 4) of the main body to be attached, and to the first part (upper body 3) of the second part which rotates relative to the first part. The coupling device further comprises a rotational force acquisition unit (hip joint torque calculation unit 104) that acquires the rotational force (hip joint torque MYh) of the first part relative to the second part.

[0133] According to (5), by obtaining the rotational force of the first part relative to the second part, the amount of power required for extension can be set more appropriately.

[0134] (6) The joint device described in (5), The rotational force acquisition unit is a coupling device that acquires the rotational force based on the angle formed.

[0135] According to (6), rotational force can be obtained accurately and easily.

[0136] (7) A coupling device as described in (5) or (6), The rotational force acquisition unit is a coupling device that acquires the rotational force based on the length of the first portion (length L of the thigh portion 4).

[0137] According to (7), rotational force can be obtained accurately and easily.

[0138] (8) A coupling device as described in any of (5) to (7), The system further includes a load acquisition unit (load / removal load acquisition unit 102) that acquires the load (load FZ) applied to the first member, The rotational force acquisition unit is a coupling device that acquires the rotational force based on the load acquired by the load acquisition unit.

[0139] According to (8), rotational force can be obtained accurately and easily.

[0140] (9) A coupling device as described in any of (5) to (8), The system further comprises the power source and a control unit (motor control unit 108, intermittent mechanism control unit 110) for controlling the first intermittent mechanism and the second intermittent mechanism, The control unit controls the amount of power generated from the power source based on the rotational force acquired by the rotational force acquisition unit, and is a coupling device.

[0141] According to (9), the amount of force required for extension can be set appropriately.

[0142] (10) First member (below-knee member 10), The second member (upper knee member 20), A connecting portion (knee joint mechanism 30) that connects the first member and the second member in a way that allows the angle between them to be changed, A joint device (electric prosthetic leg 1) comprising an expandable / contractable device (expandable / contractable device 40) capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source (motor M), It comprises a power transmission unit (transmission T) that transmits power from the aforementioned power source, The second member is configured to be attachable to the first part (thigh 4) of the main body to which the joint device is attached, and to the second part (upper body 3) which rotates relative to the first part. The aforementioned joint device is The control unit (motor control unit 108) that controls the power source, The system further includes a rotational force acquisition unit (hip joint torque calculation unit 104) that acquires the rotational force (hip joint torque MYh) of the first part relative to the second part, The control unit controls the amount of power generated from the power source based on the rotational force acquired by the rotational force acquisition unit, and is a coupling device.

[0143] According to (10), the amount of power required for extension can be set appropriately.

[0144] (11) First member (below-knee member 10), The second member (upper knee member 20), A connecting portion (knee joint mechanism 30) that connects the first member and the second member in a way that allows the angle between them to be changed, A joint device (electric prosthetic leg 1) comprising an expandable / contractable device (expandable / contractable device 40) capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source (motor M), It comprises a power transmission unit (transmission T) that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path (first gear mechanism T1) that transmits the aforementioned power at a first gear ratio, The system includes a second power transmission path (second transmission mechanism T2) that transmits the power at a second gear ratio different from the first gear ratio, The aforementioned expandable device is A first intermittent mechanism (upper clutch 50U) for switching the interruption and connection of power in the first power transmission path, The system includes a second intermittent mechanism (lower clutch 50D) for switching between interrupting and connecting power in the second power transmission path, The aforementioned joint device is The power source and the control units (motor control unit 108, intermittent mechanism control unit 110) that control the first intermittent mechanism and the second intermittent mechanism, The device further comprises a direction acquisition unit that acquires the direction of travel of the main body to which the coupling device is attached, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired by the direction of travel acquisition unit.

[0145] According to (11), by determining whether the joint is moving upward or downward, it is possible to appropriately determine the situation in which the joint is extended and the situation in which it is bent.

[0146] This application is based on a Japanese patent application (Patent Application No. 2021-032992) filed on March 2, 2021, the contents of which are incorporated by reference within this application. [Explanation of symbols]

[0147] 1. Electric prosthetic leg (joint device) 3 Upper body (second part) 4 Thigh (first part) 10. Lower leg component (first component) 20. Upper knee component (second component) 30. Knee joint mechanism (connecting part) 40 Telescopic device 50D Lower clutch (second intermittent mechanism) 50U Upper clutch (first intermittent mechanism) 102 Weighted / unloaded weight acquisition section (weighted acquisition section) 104 Hip joint torque calculation unit (rotational force acquisition unit) 108 Motor Control Unit (Control Unit) 110 Intermittent Mechanism Control Unit (Control Unit) 112 Thigh weight acquisition section (weight acquisition section) M Motor (power source) T Transmission (power transmission unit) T1 First transmission mechanism (first power transmission path) T2 Second transmission mechanism (second power transmission line)

Claims

1. First member and The second member and A connecting portion that allows the angle between the first member and the second member to be changed, A joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The aforementioned joint device is The power source and the control unit that controls the first and second intermittent mechanisms, The device further comprises a load acquisition unit that acquires the load applied to the aforementioned joint device, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the load acquired by the load acquisition unit.

2. A joint device according to claim 1, The coupling device wherein the control unit, when it detects that the load acquisition unit has transitioned from a state where no load is applied from the outside to a state where a load is applied from the outside, switches either the first intermittent mechanism or the second intermittent mechanism to a connected state.

3. A joint device according to claim 1 or 2, The device further includes a direction acquisition unit that acquires the direction of travel of the main body to which the coupling device is attached, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired by the direction of travel acquisition unit.

4. A joint device according to claim 3, The first gear ratio is defined as the ratio of the rotational speed after gear shifting to the rotational speed before gear shifting, which is the rotational speed on the power source side in the first power transmission path. When the second gear ratio is defined as the ratio of the rotational speed after gear shifting to the rotational speed before gear shifting, which is the rotational speed on the power source side in the second power transmission path, The first gear ratio is configured to be smaller than the second gear ratio. The control unit connects the first intermittent mechanism when the direction of travel acquisition unit acquires that the mounting body is moving vertically upward.

5. A joint device according to claim 4, The second member is configured to be attachable to the first part of the mounting body, which is a second part that rotates relative to the first part. The coupling device further comprises a rotational force acquisition unit that acquires the rotational force of the first part relative to the second part.

6. A joint device according to claim 5, The rotational force acquisition unit is a coupling device that acquires the rotational force based on the angle formed.

7. A joint device according to claim 5 or 6, The rotational force acquisition unit is a coupling device that acquires the rotational force based on the length of the first portion.

8. A joint device according to any one of claims 5 to 7, The load acquisition unit acquires the load applied to the first member. The rotational force acquisition unit is a coupling device that acquires the rotational force based on the load acquired by the load acquisition unit.

9. A joint device according to any one of claims 5 to 8, The control unit controls the amount of power generated from the power source based on the rotational force acquired by the rotational force acquisition unit, and is a coupling device.

10. A joint device according to any one of claims 1 to 9, The coupling device wherein the control unit, when it detects that the load acquisition unit has transitioned from a state in which a load is applied from the outside to a state in which no load is applied from the outside, switches either the first intermittent mechanism or the second intermittent mechanism to a connected state.

11. A joint device according to any one of claims 1 to 10, The aforementioned expandable device is The first interrupted state is when the first interrupted mechanism is connected and the second interrupted mechanism is disconnected, The second interrupted state is when the first interrupted mechanism is in an interrupted state and the second interrupted mechanism is in an connected state, A third intermittent state in which both the first intermittent mechanism and the second intermittent mechanism are in an interrupted state, A coupling device that can be switched between modes.

12. A joint device according to any one of claims 1 to 11, A joint device, which is a prosthetic leg device attached to the leg of the person wearing it.

13. A coupling device according to any one of claims 1 to 11, A joint device, which is a prosthetic limb device attached to the arm joint, is the primary attachment point.

14. The first member and, The second member and A connecting portion that allows the angle between the first member and the second member to be changed, A control method for a joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The control method described above is A load acquisition step for acquiring the load applied to the aforementioned joint device, The system comprises an intermittent control step for controlling the first intermittent mechanism and the second intermittent mechanism, The intermittent control step is a control method for a coupling device, in which the intermittent control step controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the load acquired in the load acquisition step.

15. A method for controlling a joint device according to claim 14, The intermittent control step is a control method for a coupling device in which, when the load acquisition step acquires that the device has transitioned from a state where no load is applied from the outside to a state where a load is applied from the outside, either the first intermittent mechanism or the second intermittent mechanism is switched to a connected state.

16. A method for controlling a joint device according to claim 14 or 15, The intermittent control step is a control method for a coupling device in which, when the load acquisition step acquires that the state has transitioned from a state in which a load is applied from the outside to a state in which no load is applied from the outside, the other of the first intermittent mechanism and the second intermittent mechanism is switched to a connected state.

17. First member and The second member and A connecting portion that allows the angle between the first member and the second member to be changed, A joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The aforementioned joint device is The power source and the control unit that controls the first and second intermittent mechanisms, The device further comprises a direction acquisition unit that acquires the direction of travel of the main body to which the coupling device is attached, The control unit controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired by the direction of travel acquisition unit.

18. A first member and, The second member and A connecting portion that allows the angle between the first member and the second member to be changed, A control method for a joint device comprising an expandable / contractable device capable of changing the angle between the first member and the second member by expanding or contracting, The aforementioned expandable device is Power source and It comprises a power transmission unit that transmits power from the aforementioned power source, The power transmission unit is A first power transmission path that transmits the aforementioned power at a first gear ratio, A second power transmission path that transmits the aforementioned power at a second gear ratio different from the first gear ratio, Equipped with, The aforementioned expandable device is A first intermittent mechanism for switching between interrupting and connecting power in the first power transmission path, The system comprises a second intermittent mechanism for switching between interrupting and connecting power in the second power transmission path, The control method described above is A process for obtaining the direction of travel of the main body to which the coupling device is attached, The system comprises an intermittent control step for controlling the first intermittent mechanism and the second intermittent mechanism, The intermittent control step is a control method for a coupling device, which controls at least one of the first intermittent mechanism and the second intermittent mechanism based on the direction of travel acquired in the direction of travel acquisition step.

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