JPH0411027Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention regulates the movement limit of each wrist component in a multi-degree-of-freedom robot wrist consisting of multiple wrist components such as a pivot axis and a swinging arm. Regarding equipment.

<Prior Art> A robot arm on which various types of work equipment are mounted at its tip usually has many degrees of freedom because it is necessary to direct the work equipment in an arbitrary direction. In order to achieve multiple degrees of freedom in the wrist at the tip of the robot arm, the multiple wrist components that make up the robot wrist are connected via joints, and each wrist component is connected to a gear mechanism or a gear mechanism. Each is driven via a power transmission mechanism such as a link mechanism. By the way, the power transmission mechanism has a structure in which the constituent members (gears, etc.) of the power transmission mechanism of each wrist constituent member are shared, due to the relationship between the combinations of the wrist constituent members and the need for simplification of the structure. There are many. Therefore, if an attempt is made to drive one wrist component of a robot arm equipped with such a power transmission mechanism, the other wrist components will also move. Therefore, in order to eliminate the above-mentioned unnecessary movement of the wrist constituent members, correction signals by software have been previously incorporated in the wrist watch. On the other hand, if each wrist component moves beyond its permissible operating range, it may cause damage or malfunction, so to prevent this,
The wrist is provided with a limit switch or the like that restricts the movement of each wrist constituent member of the wrist.

<Problems to be solved by the invention> In the above-mentioned conventional robot wrist, a limit switch, a dog, etc. that restrict the movement range of the wrist constituent members such as a pivot axis and a swing arm are incorporated into the wrist. The structure of the wrist becomes complicated and large. Also, the lead wire for the limit switch must be extended to the control section at the base of the robot, but in this case, if you do not leave enough margin for the lead wire length, the lead wire may break due to wrist movement. On the other hand, if there is a sufficient margin, another problem will occur in that the lead wire will become loose during maintenance.

In consideration of the above-mentioned drawbacks of the conventional regulating device that incorporates a limit switch or the like for regulating the movement range of each wrist component in the robot wrist, the present invention has developed a system that accommodates the movement of each wrist component. The idea was to extract the movement from the rear of the robot arm via a power transmission mechanism and to restrict this movement, thereby simplifying and downsizing the structure of the robot wrist and solving problems caused by elongating the lead wire.

<Means for solving the problem> In order to solve the above problem, the present invention includes a plurality of wrist component members each rotatable around different axes, and a drive shaft that transmits power to each wrist component. , a drive source that drives each drive shaft, a power transmission mechanism that connects each drive shaft and each wrist component and engages each other, and a power transmission mechanism when a plurality of wrist components are operated. In a robot arm consisting of a control system that compensates for interference in
At the base end side of the robot arm, each drive shaft, each wrist component, and a corresponding corresponding shaft are connected via a mechanical power transmission means, and each corresponding shaft is provided with a movement corresponding to the movement of each wrist component. A differential gear device that compensates for interference compensation movement of the drive shaft is incorporated into the mechanical power transmission means so that the movement of each wrist component is regulated based on the movement of the corresponding shaft. I made it.

<Embodiment> FIG. 1 shows a skeleton of a robot arm equipped with a regulating device according to an embodiment.
Reference numeral 1 denotes a cylindrical rotation shaft, which is rotatably supported around a central axis by a case or the like which is supported by another arm (not shown) so as to be able to rise or rise. A bevel gear 2 is fixed to the rear end of the rotating shaft, and a bevel gear 5 that is connected to a rotating motor 4 via a speed reducer 3 is meshed with the bevel gear 2 . Further, a frame body 6 forming a casing of the wrist portion is integrally attached to the tip end of the rotating shaft 1. By the operation of the rotation motor 4, the frame body 6 together with the rotation shaft 1 is rotated around its central axis (γ-axis movement).
A cylindrical swing shaft 7 is supported within the cylindrical rotation shaft 1 so as to be rotatable around its central axis, and a bevel gear 8 is fixed to the rear portion of the shaft.
A bevel gear 11 connected to a swing motor 10 via a speed reducer 9 is meshed with the gear. A bevel gear 12 is attached to the tip of the swinging shaft 7 extending inside the frame 6, and the bevel gear 12 is perpendicular to the axial direction of the swinging shaft 7 and rotates toward the frame 6. A bevel gear 14 on a freely supported gear shaft 13 is meshed. A gear 15 is provided on the gear shaft 13, and a gear shaft (swing shaft) 17, which includes a gear 16 that meshes with the gear shaft 15 and is parallel to the gear shaft 13, is rotatably supported by the frame 6. . A cylindrical swing arm 18 is integrally attached to the gear 16 on the swing shaft 17. The operation of the swing motor 10 causes the swing shaft 7 to rotate via the bevel gears 11 and 8, and the swing arm 18 rotates around the swing shaft 17 via the bevel gears 12 and 14 and the gears 15 and 16. oscillation as (β
axial movement). Inside the swinging arm 18, there is a flange portion 1 at the tip of which various operating devices are attached.
9 is rotatably supported, and a bevel gear 21 is provided at its rear end. On the other hand, a swing shaft 22 is rotatably supported within the cylindrical swing shaft 7, and a swing motor 24 is connected to its rear end via a speed reducer 23. Also, within the frame 6, the bevel gear 1 at the tip of the swinging shaft 7
A bevel gear 25 is provided at the tip of the turning shaft 22 extending forward from the rotating shaft 22, and the bevel gear 25 has a bevel gear 25 located on the same axis as the gear shaft 13 and rotatably supported by the frame 6. Bevel gear 2 on gear shaft 26
7 is interlocked. A gear 28 is provided on the gear shaft 26, and the gear 28 includes a gear shaft located on the same axis as the swing shaft 17 and rotatably supported by the frame 6 and the swing arm 18. Gears 30 on top of 29 are meshed. A bevel gear 31 that meshes with the bevel gear 21 at the rear end of the pivot shaft 20 is provided at the inner end of the gear shaft 29 that extends into the swing arm 18 . Therefore, when the turning motor 24 is driven, the turning shaft 22 rotates, and the bevel gears 25, 27 and the gear shaft 2 at the tips of the turning shaft 22 rotate.
6, gears 28, 30, gear shaft 29, bevel gear 3
1 and 20 are transmitted, and the pivot shaft 20 is rotated around its central axis (α-axis movement). In other words, the wrist portion of this robot arm consists of the frame 6, the swing arm 18, the pivot shaft 20, and the gear mechanism, and includes a rotating portion (γ-axis movement), a bending portion (β-axis movement),
It has three degrees of freedom for rotational movement (α-axis movement).

On the other hand, a sprocket 32 is installed at the rear of the rotating shaft 1.
A sprocket 34 is also attached to a separately supported rotatable shaft 33, and a chain 34a is spanned over these. A dog mounting plate 35 as shown in FIG. The rotation motor 4 is commanded to stop by contact with the dog 36 at each position corresponding to both ends of the allowable movement range (rotation angle) of the rotation shaft 1 (frame 6 in terms of the wrist). A limit switch 37 is provided.

Further, a sprocket 38 is attached to the rear end of the swinging shaft 7, and the shaft 3 provided parallel to the swinging shaft 7
A sprocket 40 is also mounted on sprocket 9, and a chain 41 is spanned between these sprockets 38 and 40. The shaft 39 and the rotation compatible shaft 3
A first differential gear device 45 is configured, each having a shaft 44 integral with a gear 43 that meshes with a gear 42 provided at three ends as an input shaft, and an output shaft (oscillating shaft) 46 at an end thereof. A swinging dog mounting plate 47 is integrally attached. When the rotating shaft 1 rotates together with the swinging shaft 7, the movement of the swinging arm 18 will interfere with each other, so a correction signal programmed in advance is used to correct the swinging arm 18 so that the desired rotation angle is obtained. The swinging dog mounting plate 47 is also rotated in accordance with the actual amount of rotation of the swinging arm 18 with interference corrected by the first differential gear device 45. A dog 73 is also attached to this dog attachment plate 47 in the same way as the rotating dog attachment plate 35,
Around it is a limit switch 74 that issues a stop command to the swing motor 10 when it comes into contact with the dog 73.
is provided.

A sprocket 48 is mounted on the turning shaft 22, and a sprocket 50 is also integrally mounted on a shaft 49 parallel to the turning shaft 22. A chain 51 is spanned between these sprockets 48 and 50, and The rotation of the shaft 22 is also transmitted to the shaft 49. A gear 52 is attached to the shaft 49, and a shaft 54 includes a gear 53 that meshes with the gear 52, and the input shaft 3 of the first differential gear device 45.
A second differential gear device 58 is constructed with a shaft 57 integral with a gear 56 that meshes with a gear 55 provided at the 9th end as an input shaft, and a gear 60 is fixed to the end of the output shaft 59. There is. A shaft 62 equipped with a gear 61 that meshes with this gear 60 is used as one input shaft, and the rotation corresponding shaft 33 and sprockets 63, 6
4. Gear 6 on shaft 66 connected by chain 65
A third differential gear device 70 is constructed with a shaft 69 having a gear 68 that meshes with the gear 7 as the other input shaft, and a swing dog mounting plate 72 is attached to the end of the swing compatible shaft 71 which is the output shaft. installed. When the rotating shaft 1 and the swinging shaft 7 rotate together with the rotating shaft 22, the rotating shaft 20 will interfere with the rotating shaft 20 and will not rotate the desired amount of rotation, but pre-installed software will compensate for the interference. controlled,
The rotation shaft 20 is rotated by the desired amount, but the rotation dog mounting plate 72 is also repaired for interference between the rotation shaft 1 and the swing shaft 7 through the two differential gear devices 58 and 70. It is rotated by an amount corresponding to the amount of rotation of the pivot shaft 20. A dog 75 is attached to this turning dog mounting plate 72 in the same way as the other dog mounting plates, and around the dog 75, the turning motor 24 is brought into contact with the dog 75 at positions corresponding to both ends of the allowable movement range.
A limit switch 76 is provided to instruct the engine to stop.

As described above, the dog mounting part 35 built into the rear part of the robot arm rotates the robot arm by an amount of rotation corresponding to the amount of rotation of the frame body 6, the swing arm 18, and the pivot shaft 20, which are the wrist components that make up the wrist part. 47,72
By tapping the fixed limit switches 37, 74, 76 with the dogs 36, 73, 75 of each dog mounting plate 35, 47, 72, the movement range of the frame 6, swing arm 8, and pivot shaft 20 can be changed. It regulates.

The differential gear devices 45, 58, and 70 serving as the rotational amount transmission compensation mechanism in the above device may be of any type, but in this embodiment, the one with the simplest structure, that is, the two input shaft side umbrellas, is used. The gears have the same number of teeth, and the bevel gears connecting these gears and driving the output shaft have the same number of teeth. Therefore, (angular displacement of one input shaft) + (angular displacement of the other input shaft)
= 1/2 (angular displacement of the output shaft).

Next, the operation of the above correction device will be explained using actual numerical values.

The diameter ratio of the sprockets 32 and 34 that connect the rotation shaft 1 and the rotation compatible shaft 33 is 1:1, and the diameter ratio of the sprockets 63 and 64 that connect the rotation compatible shaft 33 and the rotation compatible shaft 71 is 4:1. , rotation compatible axis 3
3 and one input shaft 44 of the first differential gear device 45, the tooth ratio of the gears 42 and 43 is 2:1, and the swing shaft 7 and the other input shaft of the first differential gear device 45 are The diameter ratio of the sprockets 38 and 40 that connect the rotating shaft 22 and the shaft 49 is 2:1, the diameter ratio of the sprockets 48 and 50 that connect the turning shaft 22 and the shaft 49 is 2:1, and the ratio of the number of teeth of the gears 52 and 53 is set to 2:1. 1:1, gear 55
and 56 are 1:1, gears 60 and 61 are 2:1, and gears 67 and 68 are 1:1, and the frame 6 at the wrist is set at +54°. Let us consider a case where the swing arm 18 is rotated by -79 degrees and the pivot shaft 20 is rotated by -124 degrees. In addition, the frame body 6, the rotation axis 2
0, when viewed from the arm base end side (A side in Figure 1), clockwise rotation is + and counterclockwise rotation is -, and for swinging arm 18, right side (B side in Figure 1).
When viewed from the center, clockwise direction is + and counterclockwise direction is -.

When the rotation axis 22 is rotated +9°, the rotation axis 20
rotates +9°.

Next, when the swing shaft 7 is rotated by -25 degrees, the swing arm 18 is rotated by -25 degrees, and the pivot shaft 20 is further rotated by -25 degrees.
Since it rotates, the pivot shaft 20 has rotated by -16 degrees.

Further, when the rotation shaft 1 is rotated by +54 degrees, the frame body 6 is rotated by +54 degrees, but along with this rotation, the swing arm 18 is rotated by -54 degrees, so the swing arm 18 is rotated by -79 degrees. It has rotated, and the rotation axis 2
0 rotates by -54° as the frame body 6 rotates, and
Since the swing arm 18 rotates by -54 degrees due to the rotation of the frame 6, the pivot shaft 20 also rotates by -54 degrees, and the pivot shaft 20 is finally +9 degrees - 25 degrees - 54 degrees - 54 degrees = −124°
Rotate.

On the other hand, in the dog mounting plate, the pivot shaft 22
When the rotation dog mounting plate 72 is rotated by +9°, the rotating dog mounting plate 72 is rotated by +9°.

When the swing shaft 7 is rotated by -25 degrees, the swing dog mounting plate 47 is rotated by -25 degrees, and along with this rotation, the swing dog mounting plate 72 is rotated by -25 degrees.
As a result, the dog mounting plate 72 for rotation has been rotated by -16 degrees.

Next, when the rotation shaft 1 is rotated by +54 degrees, the rotation dog mounting plate 35 is rotated by +54 degrees, but along with this rotation, the swing dog mounting plate 47 is rotated by -54 degrees, and the swing dog mounting plate 47 is rotated by -54 degrees. This means that the plate 47 has been rotated by -79°. Moreover, since the dog mounting plate 72 for rotation rotates by -108° when the rotation shaft 1 rotates by +54°, the dog mounting plate 72 for turning rotates by +9° -25° -108°.
= -124° rotation.

That is, the rotation axis 22 is set at +9°, and the swing axis 7 is set at -9°.
25 degrees, and when the rotation axis 1 is rotated +54 degrees, the pivot axis 20 at the wrist part is -124 degrees, and the swing arm 18 is -
79°, and the frame body 6 rotates +54°, whereas on the rotation extraction side of these components, the rotating dog mounting plate 72 rotates -124°, and the swinging dog mounting plate 4 rotates by -124°.
7 rotates -79°, and the rotating dog mounting plate 35 rotates +54°. In other words, the amount of rotation of the dog mounting plates 72, 47, and 35 is the same as the amount of rotation, that is, the amount of angular displacement of the wrist component members 20, 18, and 6. :1 corresponds to this. Therefore, each dog mounting plate 7 is adjusted in accordance with the allowable movement amount (angle) of the pivot shaft 20, the swing arm 18, and the frame body 6.
Limit switch 76 around 2, 47, 35,
By providing 74 and 37, the amount of movement of the pivot shaft 20, swing arm 18, and frame body 6 can be regulated.

In the robot wrist portion of the above embodiment, in order to displace the pivot shaft 20 by ±α, the pivot shaft 22 must be moved by ±α.
It is sufficient to drive by α. In order to displace the swinging arm 18 by ±β, it is sufficient to drive the swinging shaft 7 by ±β.However, as the swinging arm 18 displaces, the swinging shaft 20 also displaces, so the swinging shaft 22 is moved by ±β. ° It is necessary to drive and correct. In order to displace the frame 6 by ±γ, it is sufficient to drive the rotating shaft 1 by ±γ, but since the swing arm 18 and the pivot shaft 20 are also displaced as the frame body 6 is displaced, the swing shaft 7 and the pivot It is necessary to correct this by driving both the axes 22 in ±γ. These corrections are performed by software using the operating program for each axis.

In the embodiment shown in FIG. 1, the diameter ratio of sprockets 32 and 34 is 1:2, and sprocket 63 is
and 64 are 4:1, the gears 42 and 43 have a tooth number ratio of 2:1, the sprockets 38 and 40 have a diameter ratio of 1:1, and the sprockets 48 and 50 have a diameter ratio of 1:1. Assuming that other tooth ratios are the same as before,
When the pivot shaft 22 is rotated +9 degrees, the swing shaft 7 is rotated -25 degrees, and the rotation shaft 1 is rotated +54 degrees, the pivot shaft 20 is -
124°, the swinging arm 18 rotates -79°, and the frame 6 rotates +54°, whereas the swing dog mounting plate 72 rotates -79°.
The swinging dog mounting plate 47 rotates -39.5°, and the rotating dog mounting plate 35 rotates +27°. In other words, the rotation of the dog mounting plates 72, 47, and 35 is 1/2 of the actual rotation amount of each component of the wrist portion. In this way, the movement of the wrist component and the movement of the dog mounting plate do not need to be 1:1, but only need to be in a certain correspondence relationship.

FIG. 3 shows an embodiment in which the present invention is applied to a robot arm whose wrist portion has a structure different from that shown in FIG. 1. This includes one set of gears (gear 1
5, 16, gears 28, 30) are omitted,
Since the rotational directions of the swinging shaft 7 and the swinging arm 18 and the rotational directions of the swinging shaft 22 and the swinging shaft 20 are opposite,
In order to match the rotation direction on the rotation amount extraction side, a gear is added (gear 77 provided between the swing shaft 7 and the first differential gear device 45) or deleted (gears 52, 53). There is.

In the above configuration, the diameter ratio of sprockets 32 and 34 is 1:1, the diameter ratio of sprockets 63 and 64 is 4:1, and the ratio of the number of teeth of gears 42 and 43 is 2:1.
1. The diameter ratio of sprockets 38 and 40 is 2:
1. The diameter ratio of sprockets 48 and 50 is 2:1.
Assuming that the other tooth number ratio etc. are the same as above,
For example, the turning axis 22 is -9°, the swinging axis 7 is +25°,
When the rotation shaft 1 is rotated +54°, the rotation axis 20 is -124°, the swing arm 18 is -79°, and the frame 6 is +54°.
The rotating dog mounting plate 72 rotates by -124°, the swinging dog mounting plate 47 rotates by -79°, and the rotating dog mounting plate 35 rotates by +54°. In other words, the rotation of the dog mounting plates 72, 47, and 35 is
There is a 1:1 correspondence with the rotation or angular displacement of 0, 18, 6. If the ratio of the increments of the sprockets and gears is appropriately selected, the amount of rotation of the dog mounting plates 72, 47, 35 can be reduced to 1/2 of the rotation of the wrist components 20, 18, 6, or some other amount, as in the previous embodiment. It can be the ratio of

Note that the present invention can be applied to any type of gear mechanism other than the above-mentioned gear mechanism for transmitting power to the wrist component. Further, the degree of freedom of the wrist portion is not limited to three degrees of freedom as in the above embodiment, but can be applied to any degree of freedom of two or more.

<Effects of the invention> As explained above in detail with examples,
According to the present invention, the movement corresponding to the movement of the wrist component is detected at the proximal end of the robot arm, and based on that movement, the permissible movement range of the wrist component is regulated by regulating means such as a dog or a limit switch. As a result, there are no restrictive means such as dogs or limit switches from the wrist, the structure of the wrist is simplified, and there is no longer a need to extend lead wires to the wrist, which is much easier than conventional lead wire wiring. Eliminates wire breaks and maintenance problems.

[Brief explanation of drawings]

Figure 1 is a skeleton diagram of a regulating device according to an embodiment of the present invention, Figures 2a and b are a detailed enlarged front view and plan view of section C in Figure 1, and Figure 3 is a skeleton diagram of another embodiment. It is a diagram. In the drawing, 1 is a rotating shaft, 4 is a rotating motor, and 6 is a rotating shaft.
1 is a frame body, 7 is a swinging shaft, 10 is a swinging motor, 1
7 is a swing axis, 18 is a swing arm, 20 is a pivot axis,
22 is a rotating shaft, 24 is a rotating motor, 33 is a rotating shaft, 35 is a rotating dog mounting plate, 45, 5
8 and 70 are differential gear devices, 46 is a swinging shaft, 4
7 is a swinging dog mounting plate, 71 is a rotating shaft, 7
2 is a rotating dog mounting plate.

Claims (1)

[Scope of utility model registration request] A plurality of wrist constituent members each rotatable around different axes, a drive shaft that transmits power to each wrist constituent member, a drive source that drives each drive shaft, and each drive shaft and each wrist constituent member. A robot arm comprising a power transmission mechanism that connects and engages with each other, and a control system that compensates for interference in the power transmission mechanism when a plurality of wrist component members are operated. At the proximal end, each drive shaft, each wrist component, and a corresponding corresponding shaft are connected via a mechanical power transmission means, and each corresponding shaft is made to move in correspondence with the movement of each wrist component. A differential gear device that compensates for interference compensation movement of the drive shaft is incorporated into the mechanical power transmission means, and the permissible movement range of each wrist component is regulated based on the movement of the corresponding shaft. A robot movement limit regulating device.