WO2015166537A1

WO2015166537A1 - Robot hand, device for controlling robot hand, and method for controlling robot hand

Info

Publication number: WO2015166537A1
Application number: PCT/JP2014/061891
Authority: WO
Inventors: 鈴木　健生; 有永　雄司; 康吉田
Original assignee: 株式会社安川電機
Priority date: 2014-04-28
Filing date: 2014-04-28
Publication date: 2015-11-05

Abstract

[Problem] To make it possible to control the force of a robot hand using a simple configuration. [Solution] A robot hand (100) has: a first screw axle (1); a second screw axle (2) arranged substantially on the same axis as the first screw axle (1), the second screw axle (2) having thread grooves in the direction opposite that of the thread grooves of the first screw axle (1); a first hook member (34) that moves in the axis direction due to the rotation of the first screw axle (1); a second hook member (35) that moves in the axis direction due to the rotation of the second screw axle (2); a torsion spring (45) having elasticity in the torsion direction about the axis and connecting the first screw axle (1) and the second screw axle (2); a motor (18) provided with an output axle (18a) connected to at least one of the first screw axle (1) and the second screw axle (2) so as to enable transmission of rotational drive force; a first position detection unit (27A) configured so as to detect the rotational position of the first screw axle (1); and a second position detection unit (27B) configured so as to detect the rotational position of the second screw axle (2).

Description

Robot hand, robot hand control device, and robot hand control method

The disclosed embodiment relates to a robot hand, a robot hand control device, and a robot hand control method.

Patent Document 1 describes a robot hand that has three fingers that can be opened and closed, and each finger is independently driven by a motor with an encoder. The rotation angle of each finger is measured by an encoder, and the torque acting on the joint portion of each finger is measured by a torque sensor.

JP-A-6-335886 (FIG. 3)

The robot hand of the above prior art uses two types of sensors, a motor encoder and a torque sensor, for force control, and thus there is a problem that the configuration becomes complicated, for example, it is necessary to prepare two types of sensor power supply and cable. It was.

The present invention has been made in view of such problems, and an object thereof is to provide a robot hand, a robot hand control device, and a robot hand control method capable of performing force control with a simple configuration. .

In order to solve the above-described problem, according to one aspect of the present invention, the first screw shaft and the first screw shaft are disposed on substantially the same axis, and the first screw shaft and the direction of the screw groove are arranged. A second screw shaft that is in the opposite direction, a first claw member that moves in the axial direction by rotation of the first screw shaft, and a second claw that moves in the axial direction by rotation of the second screw shaft A member, an elastic connecting member having elasticity in a torsional direction around the axis, and connecting the first screw shaft and the second screw shaft; and at least one of the first screw shaft and the second screw shaft A robot hand comprising: a motor having an output shaft coupled to be capable of transmitting a rotational driving force; and a detecting means for detecting a torsion amount generated between the first screw shaft and the second screw shaft. Applied.

According to another aspect of the present invention, the first screw shaft and the first screw shaft are disposed substantially on the same axis, and the first screw shaft and the screw groove are opposite in direction. A second claw member that moves in the axial direction by rotation of the first screw shaft; a second claw member that moves in the axial direction by rotation of the second screw shaft; and the shaft An elastic connecting member that has elasticity in a torsional direction around the center and connects the first screw shaft and the second screw shaft; and a rotational driving force on at least one of the first screw shaft and the second screw shaft. A robot hand control device for controlling the force of a robot hand having an output shaft coupled so as to be able to transmit, the amount of twist occurring between the first screw shaft and the second screw shaft A torsion amount detection unit configured to detect Having a grip force calculating section configured to calculate a gripping force by the first pawl member and the second pawl member on the basis of the torsion amount issued, the control unit of the robot hand is applied.

According to still another aspect of the present invention, the first screw shaft and the first screw shaft are disposed substantially on the same axis, and the first screw shaft and the screw groove are in opposite directions. A second screw shaft, a first claw member that moves in the axial direction by rotation of the first screw shaft, a second claw member that moves in the axial direction by rotation of the second screw shaft, An elastic coupling member that has elasticity in a torsional direction around an axis and connects the first screw shaft and the second screw shaft; and a rotational driving force on at least one of the first screw shaft and the second screw shaft And a motor having an output shaft coupled so as to be able to transmit the force, and a robot hand control method for controlling the force of the robot hand, wherein the twist generated between the first screw shaft and the second screw shaft Detecting the amount, and based on the twist amount, the first claw member and the Calculating the gripping force by the second claw member has a control method of the robot hand is applied.

According to the present invention, the force control of the robot hand can be performed with a simple configuration.

It is sectional drawing showing an example of a structure of the robot hand which concerns on embodiment. FIG. 3 is a cross-sectional view taken along the line BB in FIG. It is a side view showing an example of composition of a robot hand concerning an embodiment. It is a top view showing an example of composition of a sensor substrate unit. It is a side view showing an example of composition of a sensor substrate unit. It is sectional drawing showing an example of a structure of a torsion joint. FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is explanatory drawing showing an example of the structure in the middle of the assembly of the robot hand which concerns on embodiment. It is a block diagram showing an example of a functional structure of a control apparatus.

Hereinafter, an embodiment will be described with reference to the drawings.

<1. Configuration of Robot Hand>
The configuration of the robot hand 100 according to the present embodiment will be described with reference to FIGS. The robot hand 100 has two claw members, and grips and releases the workpiece, for example, by operating them so as to move away from each other.

(1-1. Screw shaft and claw member)
As shown in FIG. 1, the robot hand 100 includes a first screw shaft 1, a second screw shaft 2, and a first screw moving in an axial direction (a direction parallel to the axial center AX) by the rotation of the first screw shaft 1. The claw member 34 and the second claw member 35 that moves in the axial direction by the rotation of the second screw shaft 2 are provided.

The first screw shaft 1 and the second screw shaft 2 are screw shafts having screws formed on the outer periphery, and for example, a ball screw or a slide screw is used. The first screw shaft 1 and the second screw shaft 2 are arranged so as to be substantially on the same axis with respect to the axis AX. In addition, “substantially on the same axis” here is not on the same axis in a strict sense, but on design, manufacturing tolerances, deviation or inclination of the axis due to error is allowed, It means that. In the first screw shaft 1 and the second screw shaft 2, as shown in FIG. 5A described later, the directions of the screw grooves 1a and the screw grooves 2a are opposite to each other. That is, for example, when the first screw shaft 1 is a right-hand screw, the second screw shaft 2 is a left-hand screw. In the present embodiment, for convenience of explanation, the case where the first screw shaft 1 and the second screw shaft 2 have the same screw pitch and screw diameter will be described as an example, but the present invention is not limited to this.

Bearings

3 and 4 are respectively attached to the outer end of the first screw shaft 1 and the outer end of the second screw shaft 2. As the

bearings

3 and 4, for example, end-row angular bearings are used, but are not limited thereto. The outer races of the

bearings

3 and 4 are fixed to the side plate 6 and the side plate 7 of the robot hand 100 by bonding or the like. The first screw shaft 1 and the second screw shaft 2 are rotatably supported by the side plate 6 and the side plate 7 via

bearings

3 and 4.

The inner end of the first screw shaft 1 and the inner end of the second screw shaft 2 are connected by a torsion joint 5. Details of the torsion joint 5 will be described later.

A screw nut 8 and a screw nut 10 are attached to the first screw shaft 1 and the second screw shaft 2 via screw grooves, respectively. The first screw mover 9 and the second screw mover 11 are fixed to the screw nut 8 and the screw nut 10, respectively. Further, the first claw member 34 and the second claw member 35 are fixed to the first screw mover 9 and the second screw mover 11, respectively. Thereby, the 1st claw member 34 and the 2nd claw member 35 are the 1st screw shaft 1 and the 2nd screw shaft 2 via the 1st screw mover 9 and the 2nd screw mover 11, and the screw nut 8 and the screw nut 10, respectively. It is attached to.

As shown in FIGS. 1 and 2,

linear guides

12 and 13 are provided on the hand base 50 of the robot hand 100 substantially in parallel along the direction of the axis AX. The first screw mover 9 is supported by two

linear nuts

14 and 14 on the

linear guides

12 and 13, and the second screw mover 11 is supported by two

linear nuts

15 and 15 on the

linear guides

12 and 13. Supported by The first screw moving element 9 and the second screw moving element 11 move along the

linear guides

12 and 13 in the directions approaching each other by the rotation of the first screw shaft 1 and the second screw shaft 2.

(1-2. Motor and torque transmission mechanism)
As shown in FIG. 1, the robot hand 100 includes a motor 18 having an output shaft 18a. The motor 18 is supported by the side plate 17 of the robot hand 100. As shown in FIGS. 1 and 3, the robot hand 100 includes a drive pulley 19 connected to the output shaft 18 a of the motor 18, a driven pulley 16 connected to the end of the first screw shaft 1, and a drive pulley 19. And an endless timing belt 20 (an example of an endless belt) bridged around the driven pulley 16. The side plate 6 that supports the first screw shaft 1 and the side plate 17 that supports the motor 18 have a structure that can be separated by a boundary 40. In the present embodiment, for convenience of explanation, the case where the driven pulley 16 has the same diameter as the drive pulley 19 and the same number of teeth will be described as an example, but the present invention is not limited to this. Although not shown, the driven pulley 16, the drive pulley 19, and the timing belt 20 are covered with a protective cover during the final assembly process.

When the drive pulley 19 is rotated by the motor 18, the rotational torque and the rotation direction are transmitted to the driven pulley 16 through the timing belt 20. Thereby, the 1st screw shaft 1 and the 2nd screw shaft 2 rotate, and it operates so that the 1st claw member 34 and the 2nd claw member 35 may come close to each other. Thereby, the robot hand 100 can hold and release the workpiece by the

claw members

34 and 35.

In addition, the torque transmission mechanism from the motor 18 to the first screw shaft 1 and the second screw shaft 2 is not limited to the one using the pulley and the endless belt as described above. For example, other torque transmission mechanisms such as a gear mechanism using a plurality of gears may be used. In the present embodiment, the rotational torque of the motor 18 is transmitted to the first screw shaft 1. However, the present invention is not limited to this, and may be configured to be transmitted to the second screw shaft 2. The first screw shaft 1 and the second screw shaft 2 may be transmitted to both.

(1-3. Position detector that detects the rotational position of the screw shaft)
The first position detector 27 </ b> A (an example of a detection unit) detects the rotational position of the first screw shaft 1 driven by the motor 18 by detecting the rotational position of the motor 18. In the present embodiment, the case where the first position detector 27A is a position detector of the motor 18 and is an encoder will be described as an example. However, the present invention is not limited to this. For example, a resolver that detects a rotation angle by a coil is used. Etc. can also be used.

The first position detector 27 </ b> A is configured to emit light to the first rotating disk 28 and the first rotating disk 28 connected to the end of the output shaft 18 a of the motor 18 opposite to the drive pulley 19. The first light source 29 made of, for example, an LED, and the

first encoder boards

30, 31, 32 are included. In this example, the first rotating disk 28, the first light source 29, and the first encoder boards 30 to 32 are unitized as encoder units, but those not unitized may be used. The first position detector 27A irradiates the first rotating disk 28 with light from the first light source 29, receives the light transmitted through the first rotating disk 28 with the first encoder substrate 30 which is a light receiving substrate, and receives the received light. The rotational position of the motor 18, that is, the rotational position of the first screw shaft 1 is detected from the pattern.

The first position detector 27A is not limited to the position detector of the motor 18. For example, as with the second position detector 27B, a position detector provided at the end of the first screw shaft 1 may be used as the first position detector. However, in this embodiment, the case where the 1st position detector 27A is a position detector of the motor 18 is demonstrated for convenience of explanation.

The second position detector 27B (an example of a detection unit) detects the rotational position of the second screw shaft 2 that is rotated by the first screw shaft 1 via the torsion joint 5. In the present embodiment, the case where the second position detector 27B is an encoder will be described as an example. However, the present invention is not limited to this. For example, a resolver or the like can be used.

The second position detector 27B includes a second rotating disk 21 connected to the second screw shaft 2, a second light source 22 made of, for example, an LED configured to emit light to the second rotating disk 21, and

Second encoder boards

24, 25, 26. The second light source 22 is attached to the side plate 7 of the robot hand 100, and the second rotating disk 21 is attached to the end of the second screw shaft 2 extending outward from the side plate 7. In this example, of the

second encoder boards

24, 25 and 26, two

second encoder boards

25 and 26 excluding the second encoder board 24 which is a light receiving board are configured as a sensor board unit 23 (an example of a board unit), It is provided separately from the second rotating disk 21. The second encoder substrate 24 that is a light receiving substrate is provided inside the support portion 36 c that is bent in the axial center AX direction from the unit base 36 of the sensor substrate unit 23 outside the side plate 7.

Note that the configuration of the second position detector 27B is not limited to the above. For example, similarly to the first position detector 27A, the second position detector 27B may be unitized as an encoder unit and attached to the end of the second screw shaft 2. However, as in the present embodiment, the sensor substrate unit 23 and the others are arranged separately to reduce the protrusion from the side plate 7, and the second rotary disk 21 and the second encoder substrate which is the light receiving substrate. It is easy to adjust the gap g between them. The

second encoder boards

25 and 26 may not be unitized as a board unit.

In the present embodiment, the second rotating disk 21, the second light source 22, and the

second encoder boards

24, 25, and 26 of the second position detector 27B are the first rotating disk 28 and the first encoder of the first position detector 27A, respectively. The light source 29 and the

first encoder boards

30, 31, 32 are exactly the same. As a result, the same type of sensor can be used for the first position detector 27A and the second position detector 27B, and only one type of sensor power supply or cable is required. Therefore, the configuration can be simplified. In addition, since the power supply voltage, frequency, and current value can be made the same by using the same type of sensor, even if the cables of the first position detector 27A and the second position detector 27B are arranged close to each other, noise interference is caused. There is no concern. Furthermore, the parts of both

detectors

27A and 27B can be shared, and the cost can be reduced. However, the present invention is not limited to the above, and the first position detector 27A and the second position detector 27B may be different sensors, or different parts may be used.

The first position detector 27A and the second position detector 27B are not limited to the transmissive encoder. For example, the first position detector 27A and the second position detector 27B may be reflective encoders in which the light source and the light receiving substrate are arranged on the same side with respect to the rotating disk. However, in this embodiment, the case where the 1st position detector 27A and the 2nd position detector 27B are transmission type encoders is demonstrated for convenience of explanation.

The means for detecting the amount of twist between the first screw shaft 1 and the second screw shaft 2 includes a first position detector 27A for detecting the rotational position of the first screw shaft 1 and the rotational position of the second screw shaft 2. It is not limited to two position detectors, such as the second position detector 27B for detecting the. For example, when a twist amount can be detected with a single detector, such a detector may be used. However, in this embodiment, for convenience of explanation, a case will be described in which the amount of twist is detected using two of the first position detector 27A and the second position detector 27B.

(1-4. Sensor board unit)
As shown in FIGS. 1 and 2, the sensor substrate unit 23 is provided on the unit base 36. The unit base 36 is made of, for example, a material having noise resistance and insulation. As shown in FIG. 2, in the unit base 36, both edges 36a are pressed inside the

side plates

37 and 38 of the robot hand 100, and the flat portion 36b of the unit base 36 is held between the

side plates

37 and 38 by the frictional force. It has a structure. The flat part 36b of the unit base 36 has the first screw moving element 9 and the second screw moving element 11 that translate parallelly below the sensor cable 39 drawn from the sensor board unit 23, and the first screw shaft 1 that rotates. The torsion joint 5 and the second screw shaft 2 are prevented from coming into contact with each other.

As shown in FIGS. 4A and 4B, a tunnel 47 is formed in the flat portion 36b of the unit base 36 provided with the sensor substrate unit 23, and two long screw holes 48 are formed. The second encoder board 24 provided on the support portion 36 c of the unit base 36 and the

second encoder boards

25 and 26 provided on the sensor board unit 23 are connected by a signal cable (not shown) passed through the tunnel 47. . The sensor board unit 23 is fixed to the board mounting seat 49 (see FIG. 1) of the side plate 7 by two screws (not shown) inserted through the two long screw holes 48. At that time, the adjustment of the gap g between the second rotary disk 21 and the second encoder substrate 24 is performed by shifting the screw within the long screw hole 48. Since the edge 36 a of the unit base 36 is pressed against the side plate 37 and the side plate 38, the sensor substrate unit 23 moves only in the surface direction of the

side plates

37 and 38. For this reason, the adjustment work of the gap g is easy.

(1-5. Torsion joint)
FIG. 5A and FIG. 5B show an example of the configuration of the torsion joint 5. As shown in FIG. 5A, a first screw flange 41 and a first screw boss 42 are provided at the inner end of the first screw shaft 1, and similarly, a second screw flange is provided at the inner end of the second screw shaft 2. 43 and a second screw boss 44 are provided. A slight gap is provided between the first screw boss 42 of the first screw shaft 1 and the second screw boss 44 of the second screw shaft 2 that are arranged to face each other. A torsion spring 45 (an example of an elastic connecting member) is disposed between the first screw flange 41 and the second screw flange 43 so as to cover the outer periphery of the first screw boss 42 and the second screw boss 44. The torsion spring 45 has elasticity in the torsion direction around the axis AX and connects the first screw shaft 1 and the second screw shaft 2. The torsion spring 45 is a spring configured to receive a torsional moment around the spring axis and generate a bending stress in the spring material. The inner diameter of the torsion spring 45 is slightly larger than the outer diameters of the first screw boss 42 and the second screw boss 44.

At both ends of the torsion spring 45,

spring arms

45a and 45b are provided by extension members made of a spring material when the spring is molded. The torsion spring 45 is configured such that the

spring arms

45a and 45b are inserted into the

concave grooves

41a and 43a provided in the first screw flange 41 and the second screw flange 43, respectively. Fixed to. By configuring the torsion joint 5 in this way, the rotational torque of the first screw shaft 1 is transmitted to the second screw shaft 2 via the torsion spring 45, and the first screw shaft 1 and the second screw shaft 2 are in the same direction. To be rotated.

Note that the elastic connecting member that connects the first screw shaft 1 and the second screw shaft 2 is not limited to the torsion spring. For example, a member having elasticity in the twisting direction such as a torsion bar may be used. However, in this embodiment, the case where a torsion spring is used is demonstrated for convenience of explanation.

(1-6. Robot hand assembly procedure)
FIG. 6 shows a state during assembly of the robot hand 100 of FIG. Specifically, FIG. 6 shows the first screw shaft 1, the second screw shaft 2, the

bearings

3 and 4, the torsion joint 5, the mover 9, and the hand base 50 to which the

linear guides

12 and 13 are attached. 11, the

side plates

6 and 7 and the

side plates

37 and 38 are assembled, and after the second light source 22 and the second rotating disk 21 are attached thereto, the sensor substrate unit 23 is assembled. In this assembled state, the gap g between the second rotary disk 21 and the second encoder board 24 is adjusted. This adjustment operation can be easily performed because the side plate 17 on one side of the boundary line 40 and the side plate 33 on the one side of the boundary line 51 are not assembled. That is, since the attachment of the mechanism for moving the

claw members

34 and 35 and the sensor substrate unit 23 and the attachment of the motor 18 attached to the side plate 17 as the subsequent work can be separated, the assembly work is facilitated. The attachment of the side plate 33, the canopy 52, and the

claw members

34 and 35 is an operation after adjusting the gap g. The second rotating disk 21, the second light source 22, and the second encoder board 24 are covered with a protective cover (not shown) during the final assembly process.

<2. Functional configuration of control device>
The robot hand 100 is force-controlled by the control device 60. An example of the functional configuration of the control device 60 is shown in FIG. As shown in FIG. 7, the control device 60 includes a twist amount detection unit 61, a gripping force calculation unit 62, a parameter recording unit 63, a current control unit 64, and a subtractor 65.

The twist amount detector 61 is based on the rotational position of the first screw shaft 1 input from the first position detector 27A and the rotational position of the second screw shaft 2 input from the second position detector 27B. A twist amount generated between the first screw shaft 1 and the second screw shaft 2, that is, a positional deviation (phase difference) between both rotational positions is calculated, and the calculated twist amount is output to the gripping force calculation unit 62.

The gripping force calculation unit 62 calculates and calculates the gripping force of the workpiece by the

claw members

34 and 35 based on the twist amount calculated by the twist amount detection unit 61 and the parameters recorded in the parameter recording unit 63. The calculated value of the gripping force is output to the subtracter 65.

In the parameter recording unit 63, a plurality of parameters including constants related to the elasticity of the torsion spring 45 are recorded. The plurality of parameters include, for example, the spring constant of the torsion spring 45, the screw pitch and screw diameter of the first screw shaft 1, the screw pitch and screw diameter of the second screw shaft 2, and the like.

The subtractor 65 subtracts the gripping force calculation value calculated by the gripping force calculation unit 62 from a gripping force command value (force command) set in advance (or input from a host controller not shown). The deviation of the gripping force is output to the current control unit 64.

The current control unit 64 controls the current of the motor 18 based on the deviation of the gripping force input from the subtractor 65 and controls the rotational torque of the motor 18. Thereby, the gripping force by the first claw member 34 and the second claw member 35 of the robot hand 100 is controlled.

The control device 60 applies constant thrust to the first screw moving element 9 and the second screw moving element 11 by performing constant torque control in which the rotational torque of the motor 18 is substantially constant, and thereby the first claw member 34 and the second claw member 34 and the second claw member 34. The gripping force by the claw member 35 can be made substantially constant. However, the rotational torque of the motor 18 may be varied, and the gripping force of the robot hand 100 may be varied according to the situation.

Note that the processing by the twist amount detection unit 61, the gripping force calculation unit 62, and the parameter recording unit 63 of the control device 60 is not limited to the example of sharing of these processes, and is processed by, for example, fewer processing units. Or may be processed by four or more processing units that are further subdivided.

<3. Examples of effects according to this embodiment>
As described above, the robot hand 100 according to this embodiment includes the first screw shaft 1 and the second screw shaft 2, and the first screw shaft 1 that moves in the axial direction by the rotation of the first screw shaft 1 and the second screw shaft 2. The claw member 34 and the second claw member 35, the torsion spring 45 that connects the first screw shaft 1 and the second screw shaft 2, and the motor 18 are provided. The first screw shaft 1 and the second screw shaft 2 are separated from each other, and are connected by a torsion spring 45 having elasticity in the torsion direction around the axis AX, so that the first claw member 34 and the second claw member 35 When the workpiece is gripped, the torsion spring 45 is deformed in the twisting direction according to the gripping force. At this time, by detecting the amount of twist generated between the first screw shaft 1 and the second screw shaft 2, the torque of the motor 18 is controlled based on the amount of twist and the force of the robot hand 100 is controlled. Is possible. For this reason, a force sensor for detecting a gripping force is not required, and force control can be performed with a simple configuration.

In the present embodiment, as means for detecting the amount of twist between the first screw shaft 1 and the second screw shaft 2, the first position detector 27A for detecting the rotational position of the first screw shaft 1 and the second screw When two position detectors, the second position detector 27B that detects the rotational position of the shaft 2, are used, the positional deviation between the rotational position of the first screw shaft 1 and the rotational position of the second screw shaft 2 is determined. Since the twist amount can be detected based on this, the detection accuracy of the twist amount can be improved.

In this embodiment, when the position detector of the motor 18 is used as the first position detector 27A (or the second position detector 27B), the rotational position of the position detector of the motor 18 and the screw shaft can be changed. The position detector can be shared. Thereby, the number of parts can be reduced and it can be set as a simpler structure. Further, space saving (miniaturization) and cost reduction can be achieved.

In this embodiment, when encoders are used as the first position detector 27A and the second position detector 27B, the position detection accuracy can be improved and the detection signal can be digitally output. The signal processing at is easy.

In the present embodiment, the first position detector 27A is a first encoder having a first rotary disk 28, a first light source 29, and first encoder boards 30 to 32, and the second position detector 27B is When the second encoder having the second rotating disk 21, the second light source 22, and the second encoder boards 24 to 26 is used, the following effects are obtained. That is, the same type of sensor can be used for the first position detector 27A and the second position detector 27B, and only one type of sensor power source, cable, etc. is required, and the configuration can be further simplified.

In the present embodiment, the second encoder board of the second position detector 27B (specifically, the two

boards

25, 26 excluding the board 24 of the

second encoder boards

24, 25, 26) is the second encoder board. When configured as a sensor substrate unit 23 separated from the rotating disk 21, the following effects are obtained. That is, by unitizing the

second encoder boards

25 and 26 in this way, the position of the sensor board unit 23 can be easily adjusted, and the operation of adjusting the gap g between the second rotary disk 21 and the second encoder board 24 is performed. Becomes easy.

In the present embodiment, when the driving pulley 19, the timing belt 20, and the driven pulley 16 connected to the output shaft 18a are used as a mechanism for transmitting the rotational torque of the motor 18 to the first screw shaft 1, the motor 18 Can be arranged in parallel with the first screw shaft 1, and the size of the robot hand 100 in the axial direction can be reduced. Further, when the diameters of the drive pulley 19 and the driven pulley 16 are made equal, the output shaft 18a of the motor 18 and the first screw shaft 1 have the same rotation speed. Therefore, the rotational position of the first screw shaft 1 can be accurately detected by the first position detector 27A provided in the motor 18.

In this embodiment, when the torsion spring 45 is used as an elastic connecting member for connecting the first screw shaft 1 and the second screw shaft 2, the elastic connecting member can be reduced in weight. Moreover, the fixing structure with each

screw shaft

1 and 2 can be simplified.

Further, in the present embodiment, when the control device 60 has the parameter recording unit 63, the following effects are obtained. That is, for example, when the parts such as the first screw shaft 1, the second screw shaft 2, and the torsion spring 45 are changed according to the specifications required for the robot hand 100, the parameters are recorded in the parameter recording unit 63. By changing the parameter to an appropriate value, it becomes possible to flexibly cope with the required specifications. Therefore, the degree of freedom in design can be improved.

The embodiment has been described in detail with reference to the accompanying drawings. However, the scope of the technical idea described in the claims is not limited to the embodiment described here. It is obvious that a person having ordinary knowledge in the technical field to which the present embodiment belongs can conceivably make various changes, corrections, combinations, and the like within the scope of the technical idea. Accordingly, the technology after these changes, corrections, combinations, and the like are naturally within the scope of the technical idea.

It should be noted that “parallel” and “equal” in the above description are not strictly defined. That is, “parallel” and “equal” mean “to be substantially parallel” and “substantially equal” because tolerances and errors in manufacturing are allowed in design.

DESCRIPTION OF SYMBOLS 1 1st screw shaft 1a Thread groove 2 2nd screw shaft 2a Thread groove 16 Driven pulley 18 Motor 18a Output shaft 19 Drive pulley 20 Timing belt (an example of endless belt)
21 Second rotating disk 22 Second light source 23 Sensor substrate unit (an example of substrate unit)
24, 25, 26 Second encoder board 27A First position detector (an example of detection means and first encoder)
27B 2nd position detector (an example of a detection means and a 2nd encoder)
28 First Rotating Disk 29

First Light Source

30, 31, 32 First Encoder Board 34 First Claw Member 35 Second Claw Member 45 Torsion Spring (Example of Elastic Connection Member)
60 Control Device 61 Twist Amount Detection Unit 62 Gripping Force Calculation Unit 63 Parameter Recording Unit 100 Robot Hand AX Axis Center

Claims

A first screw shaft;
A second screw shaft disposed substantially on the same axis as the first screw shaft, wherein the first screw shaft and the screw groove are in opposite directions;
A first claw member that moves in the axial direction by rotation of the first screw shaft;
A second claw member that moves in the axial direction by rotation of the second screw shaft;
An elastic connecting member having elasticity in a torsional direction around the axis and connecting the first screw shaft and the second screw shaft;
A motor comprising an output shaft coupled to at least one of the first screw shaft and the second screw shaft so as to transmit a rotational driving force;
Detecting means for detecting an amount of twist generated between the first screw shaft and the second screw shaft;
Having a robot hand.
The detection means includes
A first position detector configured to detect a rotational position of the first screw shaft;
A second position detector configured to detect a rotational position of the second screw shaft;
The robot hand according to claim 1, comprising:
The robot hand according to claim 2, wherein one of the first position detector and the second position detector is a position detector of the motor.
The first position detector and the second position detector are encoders.
The robot hand according to claim 3.
The first position detector is
A first rotating disk coupled to the output shaft of the motor;
A first light source configured to emit light to the first rotating disk;
A first encoder having a first encoder board,
The second position detector is
A second rotating disk coupled to the second screw shaft;
A second light source configured to emit light to the second rotating disk;
A second encoder having a second encoder board,
The robot hand according to claim 4.
The second encoder board is
The robot hand according to claim 5, wherein the robot hand is configured as a substrate unit separated from the second rotating disk.
A drive pulley coupled to the output shaft of the motor;
A driven pulley coupled to the first screw shaft and having the same diameter as the drive pulley;
An endless belt spanned between the driving pulley and the driven pulley;
The robot hand according to any one of claims 1 to 6.
The elastic connecting member is
A torsion spring having one end fixed to the first screw shaft and the other end fixed to the second screw shaft;
The robot hand according to any one of claims 1 to 7.
A first screw shaft, a second screw shaft that is disposed substantially on the same axis as the first screw shaft, and in which the direction of the first screw shaft and the screw groove is opposite, and the first screw shaft A first claw member that moves in the axial direction by rotation; a second claw member that moves in the axial direction by rotation of the second screw shaft; and an elasticity in a twisting direction around the axis; A motor comprising: an elastic connecting member that connects the first screw shaft and the second screw shaft; and an output shaft that is connected to at least one of the first screw shaft and the second screw shaft so as to transmit a rotational driving force. A robot hand control device for controlling the force of a robot hand having
A twist amount detector configured to detect a twist amount generated between the first screw shaft and the second screw shaft;
A gripping force calculator configured to calculate a gripping force by the first claw member and the second claw member based on the twist amount detected by the twist amount detector;
A robot hand control device.
A parameter recording unit configured to record a parameter including a constant related to elasticity of the elastic connecting member;
The grip force calculation unit
Configured to calculate the gripping force based on the twist amount and the parameter;
The robot hand control device according to claim 9.
A first screw shaft, a second screw shaft that is disposed substantially on the same axis as the first screw shaft, and in which the direction of the first screw shaft and the screw groove is opposite, and the first screw shaft A first claw member that moves in the axial direction by rotation; a second claw member that moves in the axial direction by rotation of the second screw shaft; and an elasticity in a twisting direction around the axis; A motor comprising: an elastic connecting member that connects the first screw shaft and the second screw shaft; and an output shaft that is connected to at least one of the first screw shaft and the second screw shaft so as to transmit a rotational driving force. And a robot hand control method for controlling the force of a robot hand having
Detecting the amount of twist occurring between the first screw shaft and the second screw shaft;
Calculating a gripping force by the first claw member and the second claw member based on the twist amount;
A method for controlling a robot hand.