JPH0594737U - Torque sensor for robot hand - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a torque sensor that improves workability when adjusting the tension of a medial joint, and that simplifies and downsizes the structure of the robot hand. [Structure] A pair of tension pulleys 7 and 8 capable of simultaneously pressing both reciprocating sides of a medial node 5 wound between a drive pulley 3 and a driven pulley 4 in opposite directions, and these are respectively pivotally mounted. Main frame 9, adjustment frame 10,
Fixing means 13 for integrally fixing the adjusting frame 10 to the main frame 9 and the central axes of the pair of tension pulleys 7 and 8 are provided to fix the adjusting frame 10 to the main frame 9. Adjusting means 14 for sliding movement, the main frame 9, and the adjusting frame 1
A beam 15 that supports 0 on a fixed body 16 and strain detection members 17 and 18 that detect the strain of the beam 15 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque sensor for detecting a torque of a driven pulley in a winding power transmission system, and more particularly to a torque sensor for a robot hand in driving a robot hand.

[0002]

[Prior Art]

 Since driving the robot hand requires precise position control and force control, precise measurement of the torque of the driven pulley of the wrapping power transmission system is required.

Therefore, a tension differential type torque sensor has recently been proposed in Japanese Patent Laid-Open No. 1-131423. FIG. 3 shows a schematic sectional view of a tension differential type torque sensor applied to drive a robot hand.

Next, the basic principle of the tension differential type torque sensor will be described with reference to FIG.

As shown in the figure, a power transmission system 34 is formed by winding a wire 33 as an intermediary node between a drive pulley 31 and a driven pulley 32.

Therefore, when the drive pulley 31 is driven by a motor (not shown), the torque of the drive pulley 31 is transmitted to the driven pulley 32 by the wire 33.

Then, the fingertip portion 35 attached to the driven pulley 32 moves due to the movement of the driven pulley 32 to work on a work target (not shown).

Here, when the tensions of the wires 33 at both ends of the driven pulley 32 are T ₁ and T ₂ , the torque M acting on the driven pulley 31 is expressed by the following equation. Here, R represents the half diameter of the driven pulley.

[0009]

[Equation 1]

The torque sensor 36 is composed of a tension pulley part 37 and a strain gauge part 38. When torque is applied to the driven pulley 32, the reaction force from the wire 33 is applied to each tension pulley 37, 37. F ₁ and F ₂ will act respectively.

Therefore, the torque M in Equation 1 can be expressed by the following equation. Here, k represents a constant constant, and V represents the output of the strain gauge unit 38.

[0012]

[Equation 2]

Therefore, the torque M of the driven pulley 32 is obtained in proportion to the output of the strain gauge section 38.

[0014]

[Problems to be solved by the device]

 However, since the detection sensitivity of the tension differential type torque sensor depends on the initial tension of the wire 33, conventionally, for this adjustment, the center distance between the drive pulley 31 and the driven pulley 32 is adjusted. Alternatively, a new tension adjusting pulley is provided between the pulleys 31 and 32.

Therefore, the structure of the robot hand becomes complicated and large, and the entire robot hand must be disassembled and adjusted every time the tension of the wire 33 is adjusted.

The present invention has been made in view of the above problems, and improves the workability when adjusting the tension of the intermediate joint, and simplifies and downsizes the structure of the robot hand. The purpose is to provide.

[0017]

[Means for Solving the Problems]

 The present invention is directed to a pair of tension pulleys capable of pressing both reciprocating sides of an intermediate node wound between a driving pulley and a driven pulley in opposite directions at the same time, and a tension of one of the pair of tension pulleys. A main frame to which a pulley is pivotally attached, an adjustment frame to which the other tension pulley of the pair of tension pulleys is pivotally attached, and a fixing means for integrally fixing the adjustment frame to the main frame. Adjusting means for slidingly moving the adjusting frame with respect to the main frame, the beam being provided on the central axes of the pair of tension pulleys; and a beam for supporting the main frame and the adjusting frame on a fixed body, A torque sensor for a robot hand, comprising: a strain detecting member that detects the strain of the beam.

[0018]

[Action]

 According to the present invention, the adjusting means provided in the torque sensor can set the center-to-center distance of the pair of tension pulleys to a desired value along the center axis, and the tension of the intermediate node can be set accurately. ..

[0019]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings showing an embodiment thereof.

FIG. 1 is a schematic sectional view of a robot hand using the torque sensor of the present invention. FIG. 2 is a sectional view taken along the line II in FIG. 1 embodiment.

In FIG. 1, reference numeral 1 is a fingertip portion, 2 is a power transmission system for driving the fingertip portion 1, and serves as a drive pulley 3, a driven pulley 4, and an intermediate node wound between both pulleys 3 and 4. It is composed of a wire 5 and the like.

The drive pulley 3 is driven by a motor (not shown), and the torque of the drive pulley 3 is transmitted to the driven pulley 4 by the wire 5.

Then, the fingertip portion 1 attached to the driven pulley 4 moves due to the rotation of the driven pulley 4, and performs work on a work target (not shown).

Further, the power transmission system 2 is provided with a torque sensor 6, and based on the output of the torque sensor 6, the rotation of the drive pulley 3 is controlled to perform the position control of the fingertip portion 1 and the force control. ing.

As shown in FIGS. 1 and 2, the torque sensor 6 is provided with two tension pulleys 7 and 8, one tension pulley 7 being pivotally attached to the main frame 9 and the other tension pulley 7. The reference numeral 8 is pivotally connected to an adjusting frame 10 attached to the main frame 9.

The tension pulleys 7 and 8 press the wire 5 in a direction in which both the outward path side and the return path side approach each other, that is, from the outside to the inside.

The main frame 9 is provided with an elongated hole 11 extending parallel to the central axes of the tension pulleys 7 and 8 and an elongated hole 12 into which the tension pulley 8 is inserted, and fixed in the elongated hole 11. The adjusting frame 10 is screwed onto the main frame 9 by means of screws 13 for use.

The torque sensor 6 is rotated relative to the main frame 9 by loosening the fixing screw 13 and then rotating the adjusting screw 14 provided on the central axes of the tension pulleys 7 and 8. The adjusting frame 10 is slidable.

Further, the main frame 9 is fixed to a fixed body 16 via a beam portion 15 for detecting bending strain, and strain gauges 17 and 18 for detecting the strain are provided on both sides of the beam portion 15. Is attached.

Therefore, the torque value of the driven pulley 4 is obtained from the outputs of the strain gauges 17 and 18, and the rotation of the drive pulley 3 is controlled based on the torque value to perform the position control of the fingertip portion 1 and the force control. ing.

Next, the work of setting the initial tension of the wire 5 will be described.

First, after loosening the fixing screw 13 once, the adjusting frame 14 is moved by the adjusting screw 14 in the direction along the elongated holes 11 and 12 (direction of arrow T in FIG. 2), and both adjusting screws 14 are moved. The initial tension of the wire 5 can be set by adjusting the distance between the centers of the option pulleys 7 and 8 to apply a desired tension to the wire 5, and then tightening the fixing screw 13 in that state.

Since the adjusting screw 14 is provided on the center axis of both tension pulleys 7 and 8, the distance between the centers of both tension pulleys 7 and 8 can be set along the center axis, and The initial tension adjustment of No. 5 can be performed easily and accurately.

When the detection sensitivity of the torque sensor 6 is adjusted, the center-to-center distance between the tension pulleys 7 and 8 is adjusted and the tension of the wire 5 is set, as in the initial tension setting operation described above. As a result, the detection sensitivity of the torque sensor 6 can be set to a desired value.

That is, when increasing the detection sensitivity of the torque sensor 6, the distance between the centers of the tension pulleys 7 and 8 is shortened to increase the tension of the wire 5, and conversely the detection sensitivity of the torque sensor 6 is decreased. In this case, the detection sensitivity of the torque sensor 6 can be adjusted by increasing the center distance between the tension pulleys 7 and 8 and lowering the tension of the wire 5.

In the above embodiment, the wire is used as the intermediate node wound between the drive pulley 3 and the driven pulley 4, but other intermediate nodes such as a belt may be used. ..

[0037]

[Effect of the device]

 As described above, according to the present invention, the center-to-center distance between the pair of tension pulleys can be set to a desired value along the center axis by the adjusting means provided in the torque sensor.

Therefore, it is possible to easily and accurately set the initial tension of the medium joint and the tension of the medium joint for adjusting the detection sensitivity of the torque sensor.

Further, since the tension of the intermediate joint can be set by the adjusting means provided in the torque sensor, it is not necessary to newly provide a mechanism therefor in the robot hand, and the structure of the robot hand can be simplified and downsized. Becomes

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a robot hand using a torque sensor of the present invention.

FIG. 2 is a sectional view taken along the line I-I in FIG. 1 embodiment.

FIG. 3 is a schematic cross-sectional view of a robot hand using a conventional torque sensor.

[Explanation of symbols]

 2 power transmission system 3 drive pulley 4 driven pulley 5 wire (medium node) 6 torque sensor 7, 8 tension pulley 9 main frame 10 adjustment frame 13 fixing screw 14 adjustment screw 15 beam portion 16 fixed body 17, 18 strain gauge

Claims (1)

[Scope of utility model registration request] 1. A pair of tension pulleys capable of simultaneously pressing both reciprocating sides of an intermediate node wound between a drive pulley and a driven pulley in opposite directions, and one of the pair of tension pulleys. A main frame to which is pivotally attached; an adjustment frame to which the other tension pulley of the pair of tension pulleys is pivotally attached; fixing means for integrally fixing the adjustment frame to the main frame; Is provided on the center axis of the tension pulley of
Adjusting means for slidingly moving the adjusting frame with respect to the main frame; a beam for supporting the main frame and the adjusting frame on a fixed body; and a strain detecting member for detecting a strain of the beam. A torque sensor for robot hands characterized by.