CN114248296A - Joint torque sensor of cooperative mechanical arm - Google Patents

Abstract

The invention discloses a joint torque sensor of a cooperative mechanical arm, and belongs to the field of sensors. The joint torque sensor of the cooperative mechanical arm is additionally provided with a compensation supporting beam on the traditional torque sensor, so that the actual torque of each joint can be quickly and accurately detected, and the collision of any position of the whole mechanical arm is detected. The torque sensor provided by the invention aims to solve the problems of slow collision feedback and low safety of the existing mechanical arm, and the supporting rigidity of the torque sensor in the non-torque measuring direction can be effectively improved by additionally arranging the compensation supporting beam, so that the positioning precision of the tail end of the robot is improved.

Description

Joint torque sensor of cooperative mechanical arm

Technical Field

The invention relates to the field of sensors, in particular to a joint torque sensor of a cooperative mechanical arm.

Background

With the progress of the automation industry, the application of the mechanical arm is more and more extensive. Traditional industrial robots cannot interact with the environment, and serious injury is caused if people accidentally enter the robot in a working range, so that the cooperative robot is produced. Most of the existing cooperative robots in the market adopt a motor current feedback principle to detect whether the mechanical arm has accidental collision or not, and the cooperative robots have the defects of low sensitivity, incapability of accurately controlling terminal force values and the like.

Disclosure of Invention

In order to solve the problems of slow collision feedback and low safety of the existing mechanical arm, the invention provides a method for mounting a torque sensor at a joint of the mechanical arm, and meanwhile, a compensation supporting beam is additionally arranged on the traditional torque sensor, so that the actual torque of each joint can be quickly and accurately detected, the collision of any position of the whole mechanical arm is detected, the sensitivity is high, the feedback is rapid, and the safety is higher.

In view of the above situation, the invention provides a cooperative mechanical arm joint torque sensor, which comprises a first flange and a second flange which are horizontally arranged according to the same circle center, wherein the first flange is used for connecting a mechanical arm shell, the second flange is used for connecting a harmonic reducer, the first flange and the second flange are fixedly connected through a plurality of horizontally arranged stress beams, the interval between any two stress beams is the same, each stress beam comprises a torque measuring part, a shearing strain gauge is attached to the torque measuring part, a compensation support beam is arranged between any two stress beams, the distance between each compensation support beam and two adjacent stress beams is equal, and the compensation support beams are used for buffering axial force and bending moment and improving the lateral force resistance of the torque sensor.

As a preferred embodiment, the compensating support beam includes a main beam and two buffer areas, the main beam is a vertically disposed thin sheet, the two buffer areas are respectively located at the connection positions of the thin sheet and the second flange and the first flange, the boundary of each buffer area is two symmetrically disposed circular arc thin sheets, one end of each circular arc thin sheet is connected to the compensating support beam, the other end of each circular arc thin sheet is connected to the outer side of the corresponding second flange or the inner side of the corresponding first flange, and the compensating support beam is disposed along the normal direction of the stress beam.

In a preferred embodiment, the main beam of the compensating support beam and the buffer zones are integrally formed, the two circular arc sheets of each buffer zone are back to back tangent, the tangent point is the connection point of the buffer area and the main beam, the other end of each arc sheet is tangentially connected with the second flange or the first flange, the height of the top of the compensation support beam is higher than that of the top of the stress beam, the height of the bottom of the compensation support beam is lower than that of the bottom of the stress beam, because the traditional stress beam adhered with the strain gauge mostly adopts a wide and thin model for acquiring the shearing strain, therefore, the lateral force resistance is very weak, the axial height of the main beam of the compensation support beam is greater than that of the stress beam, so that the axial force and the bending moment with a great proportion can be borne, meanwhile, due to the fact that the vertical thin sheets are arranged, torsional rigidity is low, and shear stress can still be concentrated on the strain gauge of the stress beam when the stress beam is subjected to torque.

As a preferred embodiment, each strain gage of the stress beam is provided with a flexible isolation groove, the flexible isolation groove is located at a connection position of the torque measurement position and the second flange and the first flange, two sides of the torque measurement position are also provided with an integrally formed auxiliary beam in a direction perpendicular to the flexible isolation groove, and the flexible isolation groove can separate direct connection of the torque measurement position and the second flange and the first flange, so that internal normal stress cannot be directly transmitted to the strain gage when the strain gage receives lateral force, but the auxiliary beams on two sides bear shear stress, and therefore the torque can be accurately measured under the condition that the torque sensor is subjected to complex stress without being influenced by forces in other directions.

As a preferred embodiment, the number of the stress beams and the number of the compensation support beams are 4, and any two adjacent stress beams and compensation support beams are arranged at an included angle of 45 degrees, so that the structure is simple, and the cost is lower under the same torque measurement efficiency.

As a preferred embodiment, the width of the flexible isolation groove is smaller than the width between two flexible isolation grooves on the same torque measurement location, the height of the top of the strain gauge is lower than the height of the top of the auxiliary beam, the height of the bottom of the strain gauge is higher than the height of the bottom of the auxiliary beam, so as to ensure that the stress of the compensation support beam is narrow and high, and the stress beam is wide and flat, thereby ensuring that the compensation support beam can effectively replace the stress beam to bear axial force, lateral force and lateral bending moment.

In conclusion, the invention has the following beneficial effects: by the method of additionally arranging the compensation supporting beam in the traditional torque sensor, the actual torque at the joint of the mechanical arm can be measured more accurately, force value coupling is avoided being eliminated under the condition that the torque sensor senses other forces, and the measurement precision is improved; in addition, the compensation supporting beam can improve the supporting rigidity of the torque sensor in the non-torque measuring direction, so that the positioning precision of the tail end of the robot is improved.

Drawings

FIG. 1 is a schematic diagram of a torque sensor according to the present invention

FIG. 2 is a perspective view of a torque sensor according to the present invention

Wherein 1 is the second flange, 2 is the first flange, 3 is the compensation supporting beam, 31 is the buffer zone, 32 is the main beam, 4 is the stress beam, 41 is the flexible isolation groove, 42 is the torque measurement department, 43 is the auxiliary beam

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

In an embodiment, as shown in fig. 1, the cooperative mechanical arm joint torque sensor provided by the invention comprises a first flange 2 and a second flange 1 which are horizontally arranged according to the same circle center, wherein the first flange 2 is used for connecting a mechanical arm shell, the second flange 1 is used for connecting a harmonic reducer, the first flange 2 and the second flange 1 are fixedly connected through 4 horizontally arranged stress beams 4, the interval between any two stress beams 4 is the same, each stress beam 4 comprises a torque measurement part 42, a shearing strain gauge is attached to each torque measurement part 42, a compensation support beam 3 is arranged between any two stress beams 4, the distance between each compensation support beam 3 and two adjacent stress beams 4 is equal, the compensation support beam 3 is used for buffering axial force and bending moment, and the lateral force resistance of the torque sensor is improved, compensating supporting beam 3 includes a slice girder 32 and two buffers 31, girder 32 is the vertical thin slice of placing, two buffers 31 are located the junction of thin slice and second flange 1 and first flange 2 respectively, every buffer 31's border is the circular arc thin slice of two symmetry settings, the one end of circular arc thin slice with compensating supporting beam 3 links to each other, and the other end is connected with the second flange 1 outside or first flange 2 inboard that correspond, and compensating supporting beam 3 sets up along stress beam 4's normal direction, and the condition of axial torque can only be considered under the operating mode in comparison with ordinary torque sensor, compensating supporting beam 3's vertical setting can alleviate the influence of the lateral force that torque sensor received, axial force and lateral bending moment effectively. The main beam 32 and the buffer zones 31 of the compensating support beam 3 are integrally formed, two arc sheets of each buffer zone 31 are tangent back to back, and the tangent point is the connection point of the buffer zone 31 and the main beam 32, the other end of each arc sheet is tangentially connected with the second flange 1 or the first flange 2, the height of the top of the compensating support beam 3 is higher than that of the top of the stress beam 4, the height of the bottom of the compensating support beam 3 is lower than that of the bottom of the stress beam 4, because the traditional stress beam 4 stuck with the strain gauge mostly adopts a wide and thin model for acquiring shear strain, therefore, the lateral force resistance is weak, the axial height of the main beam 32 of the compensation support beam 3 is greater than that of the stress beam 4, so that a great proportion of axial force and bending moment can be borne, meanwhile, due to the vertical thin sheet, the torsional rigidity is low, and the shear stress can still be concentrated at the strain gauge of the stress beam 4 when the strain gauge is subjected to torque. Each torque measurement department 42 of stress beam 4 is provided with flexible isolation groove 41, flexible isolation groove 41 is located the junction of torque measurement department 42 and second flange 1 and first flange 2, still be provided with integrated into one piece's auxiliary beam 43 on the direction of the both sides perpendicular to flexible isolation groove 41 of foil gage, flexible isolation groove 41 can separate the direct connection of torque measurement department 42 and second flange 1 and first flange 2, makes it can't directly transmit to the foil gage when receiving the side force inside normal stress, but bears the shear stress through the auxiliary beam 43 of both sides, from guaranteeing that the torque sensor also can be accurate under complicated atress condition measure the moment of torsion not influenced by other direction forces. Any two adjacent stress beams 4 and the compensation support beam 3 are arranged at an included angle of 45 degrees, the structure is simple, and the cost is lower under the same torque measurement efficiency. The width of the flexible isolation groove 41 is smaller than the width between two flexible isolation grooves 41 on the same torque measurement position 42, the height of the top of the strain gauge is lower than that of the top of the auxiliary beam 43, the height of the bottom of the strain gauge is higher than that of the bottom of the auxiliary beam 43, the stress of the compensation support beam 3 is ensured to be narrow and high, and the stress beam 4 is wide and flat, so that the compensation support beam 3 can be ensured to effectively replace the stress beam 4 to bear axial force, lateral force and lateral bending moment.

In this embodiment, the second flange 1 and the first flange 2 are used for connecting the harmonic reducer and the mechanical arm housing, when an axial torque is applied, an ideal shearing strain is generated at the torque measurement position 42, and the strain is collected by the adhering and shearing type strain gauge and converted into an electric signal, so that the torque is measured. The torque sensor provided by the invention can effectively divide the stress in different directions, so that the stress at the torque measuring part 42 is concentrated, the sensitivity is high, the stress at the torque measuring part 42 can be still kept to be 0 even if the torque sensor is subjected to axial force, lateral force and bending moment, and the interference on the torque measurement is avoided.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.

Claims (6)

1. The utility model provides a cooperation arm joint torque sensor, includes first flange and the second flange that sets up according to same centre of a circle level, first flange is used for connecting the arm shell of machinery, the second flange is used for connecting the harmonic reduction gear, first flange with through the stress beam fixed connection of a plurality of level setting between the second flange, arbitrary two the interval is the same between the stress beam, every the stress beam includes a torque measurement department, the torque measurement department all pastes and cuts and show the foil gage, its characterized in that: all be provided with compensation supporting beam between arbitrary two the stress beam, every the distance between two adjacent stress beams of compensation supporting beam distance equals, compensation supporting beam is used for buffering axial force and moment of flexure, promotes torque sensor's anti lateral force ability.

2. The cooperative mechanical arm joint torque sensor as recited in claim 1, wherein: the compensating support beam comprises a main beam and two buffer areas, the main beam is a vertically placed sheet, the two buffer areas are respectively located at the connecting positions of the sheet and the second flange and the first flange, each buffer area is defined by two symmetrically arranged arc sheets, one end of each arc sheet is connected with the compensating support beam, and the other end of each arc sheet is connected with the outer side of the corresponding second flange or the inner side of the corresponding first flange.

3. The cooperative mechanical arm joint torque sensor as recited in claim 2, wherein: compensating supporting beam's girder and buffer integrated into one piece, two of every buffer the circular arc thin slice is tangent in the opposite directions, and the tangent point is the tie point of buffer and girder, every the other end and the second flange or the first flange tangential connection of circular arc thin slice, the height at compensating supporting beam top is higher than the height at stress beam top, the height of compensating supporting beam bottom is less than the height of stress beam bottom.

4. The cooperative mechanical arm joint torque sensor as recited in claim 1, wherein: each flexible isolation groove is formed in the torque measurement position of each stress beam, the flexible isolation grooves are located at the connection position of the torque measurement position and the second flange and the first flange, and integrally formed auxiliary beams are further arranged on the two sides of the torque measurement position in the direction perpendicular to the flexible isolation grooves.

5. The cooperative mechanical arm joint torque sensor as recited in claim 1, wherein: the number of the stress beams and the number of the compensation supporting beams are both 4.

6. The cooperative mechanical arm joint torque sensor as recited in claim 4, wherein: the width of the flexible isolation groove is smaller than the width between two flexible isolation grooves on the same torque measurement position, the height of the top of the strain gauge is lower than that of the top of the auxiliary beam, and the height of the bottom of the strain gauge is higher than that of the bottom of the auxiliary beam.

Images