DE102016212407A1 - Sensor plate for attachment to a manipulator - Google Patents

Abstract

The invention relates to a sensor plate (1, 1 ') for attachment to a manipulator (10), which is designed to be connected to the manipulator (10) with one of its sides (3) and to its opposite side (5). with a manipulator base (12) or with an end effector. The sensor plate has a first (40) and a second fastening region (50), which are connected to one another via at least two webs (60, 61, 62, 63, 64, 65). The webs (60, 61, 62, 63, 64, 65) are provided with sensors (70) to detect acting forces upon relative movement of the first and second attachment portions (40, 50) to each other.

Description

1. Technical area

The present invention relates to a sensor plate for attachment to a manipulator which is adapted to be connected to the manipulator at one of its sides and to a manipulator base or an end effector with its opposite side for applying forces to the manipulator to capture.

2. Technical background

A manipulator, and in particular an industrial robot, is a freely programmable, program-controlled handling device. Manipulators often consist of several moveable, interlinked links or axles that define a kinematic chain. Articulated robots, for example, have several articulated links that allow flexible handling of objects. It is known to provide manipulators with force or torque sensors for detecting the forces occurring in the axes of the movable members. The detected forces are used to control the manipulator and in particular to make the operation of the manipulator safer.

From the DE 10 2007 050 232 A1 The same applicant is aware of the use of force sensors for detecting forces occurring at the robot base or the robot base. The sensors are provided in addition to the force sensors on the axes of the robot and provide a redundant sensor arrangement. The determined by the redundant sensors forces and torques in the relevant component of the robot must be the sum of the forces or moments that were determined by the axle sensors. Thus, these can be checked for conclusiveness and possibly a malfunction can be detected.

For example, if a manipulator is moved on an external axis, such as on a linear axis, collisions of its structure with the environment may be detected via the above-described force sensors in the axes of the manipulator. However, collisions of the Manipulatorfußes or the axis 1 of the manipulator and the environment can be detected only insufficiently. If sensors are firmly integrated into the base, the sensor assembly is not sensitive enough in certain circumstances. Depending on the application, this can impair safe operation of the manipulator.

It is therefore an object of the present invention to provide a means by which the operation of manipulators can be made safer. In particular, it is an object of the present invention to provide a means by which forces can be detected and thus, for example, collisions can be detected which occur directly at the manipulator foot and / or at the hand flange of the manipulator to which the end effector is typically fastened. It is a further object of the invention to provide a manipulator system having such means.

These and other objects, which will become apparent upon reading the following description, are achieved by a sensor plate according to claim 1 and a manipulator system according to claim 15.

3. Content of the invention

In particular, the invention relates to a sensor plate for attachment to a manipulator, wherein the sensor plate is adapted to be connected with one of its sides with the manipulator and with its opposite side with a manipulator base or with an end effector. The use of such a plate is particularly space-saving and changes the footprint of the provided with such a plate manipulator only slightly. For attachment or connection, the sensor plate has a first and a second attachment region, which are connected to one another via at least two webs or struts, wherein the webs or struts are designed such that a relative movement of the two attachment regions to each other. The first attachment region has means for attachment to the manipulator and the second attachment region means for attachment to the manipulator base or the end effector. A relative movement of the manipulator to the manipulator base or of the manipulator to the end effector therefore also causes a relative movement of the two attachment areas to one another. The webs are provided with sensors to detect forces acting on a relative movement of the first and second attachment areas to each other. It is clear to the person skilled in the art that with a relative movement typically only very small movements within the scope of fractions of millimeters are meant. In fact, it is preferable if the relative movement of the first and second attachment areas to each other is limited to a few millimeters or fractions of millimeters (eg, by correspondingly rigid lands), since the relative movement is essentially only to capture acting forces ,

Such a sensor plate allows, for example, the detection of collisions with the Manipulatorfuß when the plate is set up for example between the manipulator and manipulator base. The sensor plate thus makes the structure of an articulated arm robot, for example, sensitive downwards from axis 1 in order to be able to reliably detect collisions and to be able to respond accordingly to them safely. By a two-part sensor plate with first and second mounting areas, which are interconnected by webs, translational forces can be reliably detected. Due to the training as a plate, this can find space under the Manipulatorfuß and thus contributes little. Particular advantages arise when the manipulator is mounted on a movably mounted manipulator base, which can be moved for example by means of a linear axis. In this case, namely collisions of the manipulator foot or the axis 1 and the environment can be reliably detected, which can occur when the manipulator is moved on its manipulator base by means of the linear axis.

Preferably, the sensor plate is formed such that one of the attachment regions encloses the other attachment region and wherein the webs connect the two regions in the manner of wheel spokes. In this case, the other attachment area does not necessarily have to be completely enclosed, although this is preferred for reasons of stability. If, for certain reasons, increased stability can be dispensed with, then one attachment area can also enclose the other, for example, only three quarters, and thus around 270 °. This structure allows a compact construction with good functionality at the same time. For example, the enclosing fastening region may be formed as a ring and completely enclose the other fastening region. Thus, the cross section of the sensor plate is substantially circular, which allows a good connection to the manipulator, manipulator base or end effector, since typically the attachment interfaces of these elements are circular or flange-like.

Preferably, the fixing area arranged inside is not circular. For example, it may be substantially rectangular, with the longitudinal orientation being greater than the width. Such a construction allows a particularly good adaptation of the sensor plate to the intended installation situation. If, for example, it is to be expected that the strongest forces act from certain directions, as is the case with the use of the manipulator with a linear axis, then the sensor plate can be oriented accordingly, since the elongated fastening area accommodates higher forces in the interior, typically in the longitudinal direction can.

Preferably, two main webs are arranged opposite each other and further arranged at least two side webs opposite and offset by 90 ° to the main webs. Such a sensor plate thus has substantially four webs or struts which point in four opposite directions in one plane. This type of construction allows a particularly wide field of detection of occurring forces.

It is further preferred that the two main webs are trapezoidal. The shape of the webs influences the behavior of the sensor plate when exposed to external forces. Depending on the geometric design, such as the thickness of the webs and cross-sectional shape of the webs (that is, the area moment of inertia), these different stiffness, depending on which direction the external forces act.

The sensors preferably comprise strain gauges or are based on strain gauges or are strain gauges. The use of strain gauges for detecting forces and torques is basically known to the person skilled in the art, so that a detailed description of the same can be dispensed with here. Strain gauges are measuring devices for the detection of expanding and compressive deformations that change their electrical resistance even with the slightest deformation. By the provision of strain gauges at suitable locations of the webs even the slightest deformation of the webs can be detected, which occur when it comes to relative movements of the first and second mounting areas to each other. Therefore, it is possible to make the webs relatively rigid, so that even with large forces occurring only very small relative movements of the first and second mounting areas to each other. This allows a particularly secure and robust construction of the sensor plate.

Preferably, the strain gauges are arranged in the region of the smallest cross section at the webs. This allows an advantageously higher sensitivity of the sensors.

Preferably, at least two strain gauges per web are provided, which are arranged on opposite surfaces of the respective web. By using four bars with two strain gauges each, effective forces can be reliably detected over a wide range. It is clear to the person skilled in the art that not necessarily all existing webs must be provided with strain gauges. It is also conceivable to provide additional webs, which serve only the mechanical stability. Particularly preferred are four strain gauges per web provided, which are each arranged in pairs on opposite surfaces of the web. Such a construction allows, for example, the strain gauges on at least one bridge as a full bridge to set up. This can be effectively reduced interference, which is preferably due to a corresponding interconnection, and resolutions in the range of a few Newton can be achieved.

Preferably, the sensor plate is provided with at least one blocking means for limiting the relative movement of the two attachment areas to each other. The blocking means may be about a rigid mechanical stop and advantageously prevents excessively large forces from damaging or breaking the bars.

Preferably, the at least one blocking means is designed as a pin, which is inserted in mutually aligned bores in the first and second attachment region and extends from the bore in the first attachment region into the bore in the second attachment region. The pin can for example be firmly fitted in one of the two holes and extend with play in the other hole. Upon excessive relative movement of the first and second attachment portions, which may occur when particularly strong forces are applied to the manipulator, the pin or pins provides an effective mechanical safeguard. In particular, the pin or the pins prevent the webs from being broken in the case of very strong forces and the first fastening area being detached from the second fastening area.

Preferably, a mounting portion of the sensor plate is annular and the other is disposed inside the ring shape, so that the webs connect the two attachment portions in the manner of wheel spokes. At least two opposite webs advantageously have a rectangular cross-section which is constant in the radial direction, ie. H. does not taper in the radial direction or the like. Such a form of the webs is inexpensive to produce and allows a good adjustment of the bending behavior of the webs and thus the movement behavior of the two thus connected attachment areas.

Preferably, the height of the rectangular cross section in the direction orthogonal to the main plane of the sensor plate is at least five times greater than the width of the rectangular cross section, more preferably at least eight times greater than the width and even more preferably at least ten times greater than the width. Such a cross section provides a very high resistance to forces acting orthogonal to the main plane of the sensor plate on the web and very little resistance to forces acting in the direction of the main plane.

Particularly preferably, the sensor plate has at least two further opposing webs with trapezoidal cross-section, which are arranged offset by 90 ° to the at least two opposite webs with a rectangular cross section, wherein the cross section of the two further webs tapers in the radial direction. The trapezoidal cross section or the associated taper in the radial direction causes these webs, for example, have a very high resistance to forces acting on them in the radial direction. Due to the trapezoidal shape or taper the stiffness and thus the resistance of these webs is reduced compared to other directions of force, whereby in these directions increased sensitivity is achieved.

The invention also relates to a manipulator system comprising a manipulator and a sensor plate as described above, wherein the sensor plate is attached to the manipulator between manipulator and manipulator base or between manipulator and end effector. As mentioned above, the provision of a sensor plate between manipulator and manipulator base allows the detection of collisions of the manipulator foot with the environment, which is not possible with conventional manipulator systems. This is particularly advantageous in cases where the manipulator base is arranged to be movable, such as on a linear axis.

In principle, it is preferred that one of the attachment regions surrounds the other attachment region of the sensor plate, and the manipulator base is fastened to the interior of the two attachment regions and the manipulator is fastened to the other attachment region.

4. Character description

In the following, the present invention will be described in detail with reference to the accompanying drawings. The same elements are provided with the same reference characters. Show it:

1 in a schematic view of a manipulator which is adapted to move on a linear axis;

2 a manipulator with a sensor plate according to the invention;

3 a sensor plate according to the invention in three-dimensional view;

4 the sensor plate of 3 in a plan view;

5 another sensor plate according to the invention; and

6 schematically the attachment and interconnection of strain gauges.

In particular shows 1 a three-dimensional schematic view of a manipulator 10 in the form of an articulated arm robot. The manipulator 10 is with his manipulator foot 11 on a pedestal 12 attached. The base 12 is on a linear axis 14 movably furnished. In this way, the manipulator 10 be moved back and forth in the longitudinal direction. The axes of the manipulator 10 are equipped with torque sensors (not visible in 1 ), so that collisions in the field 17 can be detected via these axle sensors. Collisions of the foot 11 however, can not be detected via the axle sensors, so the range 16 in which the manipulator is linear by means of the linear axis 14 can not be moved.

2 shows a schematic view of the manipulator 10 in a side view. The manipulator 10 has at its free end a hand flange 13 for attaching an end effector 15 on. The foot 11 used for connection to the manipulator socket. In the in 2 shown embodiment is the manipulator foot 11 with a sensor plate 1 connected. The sensor plate 1 is due to the size of the manipulator foot 11 adapted and increases the size of the manipulator 10 barely. There is also another sensor plate 1 between hand flange 13 and end effector 15 intended. When the manipulator 10 with the sensor plate 1 eg on the movable manipulator base 11 is attached (see again 1 ), so can the range 16 be monitored safely.

In 3 is a sensor plate 1 shown in a schematic, three-dimensional view. The sensor plate 1 has a page 3 for example, which is connected to the manipulator and an opposite side 5 which can be connected to a manipulator socket or to an end effector. For this purpose, the sensor plate 1 a first attachment area 40 and a second attachment area 50 on. The first attachment area 40 encloses the second attachment area 50 , It can be seen that the first attachment area 40 is annular and the second mounting area 50 is arranged completely within the ring shape. In the example shown, the first attachment area encloses 40 the second attachment area 50 completely, however, it is equally conceivable that he has the second attachment area 50 only partially encloses. The two attachment areas 40 and 50 are over a number of jetties 60 . 61 . 62 . 63 . 64 , and 65 connected with each other. In the case shown, the webs are formed integrally with the two attachment areas. However, it is also conceivable to connect the webs with the two attachment areas in other ways, such as via a welded joint or via mechanical connection means. The webs are formed such that, although there is a relatively rigid connection between the first and the second attachment region, but a relative movement of the two attachment regions to each other is still possible. Preferably, the webs are formed, ie strong enough that the relative movement is only a few millimeters, preferably only fractions of a millimeter, even if relatively strong forces act.

In the example shown, the first attachment area 40 for attachment with a manipulator or the manipulator 10 set up. For this purpose, the first fastening region has corresponding means in the form of through holes 41 and 42 on to with the manipulator foot 11 of the manipulator 10 to be connected via a screw connection. The second attachment area 50 also has funds in the form of holes 51 for attachment to the manipulator base. In the orientation shown in 3 would the manipulator socket on the side 5 (ie the back in 3 ) and the manipulator 10 on the side 3 the sensor plate 1 (ie on the visible front in 3 ).

One recognizes that the webs 60 . 61 . 62 . 63 . 64 . 65 connect the two attachment areas in the manner of wheel spokes. The webs are provided with different cross sections. One recognizes in the 3 two main bridges 60 and 61 , which have a relatively large cross-section and four thinner side bars, which are arranged offset from the main webs by 90 °. The main bridges 60 . 61 are trapezoidal. In the example shown, the cross section of the main webs tapers in the radial direction to the outside. All bars are with strain gauges 70 provided with which compressions or bends of the webs can be detected, which occur when the two mounting portions are moved relative to each other. A relative movement of the two attachment regions occurs, for example, when in the mounted state of the sensor plate 1 the manipulator foot 11 for example, colliding with an object of the environment. The bending of the webs is in the known way of the strain gauges 70 detects and thus allows a determination of the forces acting on the relative movement of the first and second attachment areas to each other.

In the case shown in each case two strain gauges are provided per web, wherein the two strain gauges are arranged on opposite surfaces of the respective web. In the three-dimensional view of 3 is due to the perspective, always just a strain gauge 70 to see.

To prevent excessive relative movement of the two attachment areas, the sensor plate is 1 provided with blocking means for limiting the relative movement. The blocking means also serve as a safeguard against excessive forces which could eventually lead to breakage of the webs, which would cause the second mounting area to disengage from the first mounting area, with potentially dangerous consequences. In the illustrated example, the blocking means are as a pen 81 formed, in aligned bores 80 in the first attachment area 40 and corresponding holes 82 in the second attachment area 50 is used. Here is the diameter of the hole 82 in the second attachment region preferably designed such that the pin 81 stuck in hole 82 is held. The hole 80 in the first attachment area 40 on the other hand has a diameter that is slightly larger than the diameter of the pen 81 so that the pin is in the hole 80 has a certain freedom of movement. This range of motion is preferably only a few millimeters, more preferably only fractions of a millimeter. As from the representation of 3 can be seen, the sensor plate has 1 four such pins 81 and corresponding holes in the first and second attachment area.

From the three-dimensional view of 3 it can be seen that the webs 62 . 63 . 64 . 65 have a rectangular cross-section which is constant in the radial direction. The height of the rectangular cross section h in the direction orthogonal to the main plane of the sensor plate is approximately eight times greater than the width b of the rectangular cross section. The bridges 62 . 63 . 64 . 65 are oriented in such a way that the side surfaces of the webs, ie the main surfaces, are orthogonal to the main plane of the sensor plate.

The bridges 60 . 61 have a trapezoidal cross section, which tapers in the radial direction. The person skilled in the art recognizes that the shape and configuration of the webs determines the bending resistance during a relative movement of the first and second fastening areas relative to one another.

In 5 is a slightly modified sensor plate 1' shown. The sensor plate 1' essentially corresponds to the sensor plate 1 with the difference being that the shape of the second attachment area 50 ' is not circular, but has a substantially rectangular shape, with unequal side lengths.

In 6 schematically shows the arrangement of four strain gauges DMS1 to DMS4 on the side surfaces of a web 66 shown in a plan view. The four strain gages DMS1 to DMS4 are set up as full bridges. The use of a full bridge allows, inter alia, the compensation of temperature-induced strain.

LIST OF REFERENCE NUMBERS

1, 1 '

sensor plate

3

Side of the sensor plate

5

opposite side of the sensor plate

10

manipulator

11

Manipulatorfuß

12

manipulator base

13

hand flange

14

linear axis

40

first attachment area

41, 42

Through holes

50, 50 '

second attachment area

51

drilling

60, 61, 62, 63, 64, 65, 66

Stege

70

Sensor (strain gauges)

80, 82

drilling

81

pen

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007050232 A1 [0003]

Claims (17)

Sensor plate ( 1 ; 1' ) for attachment to a manipulator ( 10 ), wherein the sensor plate is designed to engage with one of its sides ( 3 ) with the manipulator ( 10 ) and with its opposite side ( 5 ) with a manipulator socket ( 12 ) or with an end effector ( 15 ), wherein the sensor plate a first ( 40 ) and a second attachment area ( 50 ), which via at least two webs ( 60 . 61 . 62 . 63 . 64 . 65 ), the webs ( 60 . 61 . 62 . 63 . 64 . 65 ) are adapted to prevent relative movement of the two attachment areas ( 40 . 50 ), the first attachment area ( 40 ) Medium ( 41 . 42 ) to a fixture with the manipulator ( 10 ) and the second attachment area ( 50 ) Medium ( 51 ) for attachment to the manipulator base ( 12 ) or the end effector ( 15 ), and wherein the webs ( 60 . 61 . 62 . 63 . 64 . 65 ) with sensors ( 70 ) are provided to act on forces during relative movement of the first and second attachment areas ( 40 . 50 ) to each other. Sensor plate ( 1 ; 1' ) according to claim 1, wherein one of the attachment areas ( 40 ) the other attachment area ( 50 ) and the webs ( 60 . 61 . 62 . 63 . 64 . 65 ) the two attachment areas ( 40 . 50 ) in the manner of wheel spokes. Sensor plate ( 1 ; 1' ) according to claim 1 or 2, wherein the fixing area arranged inside ( 50 ' ) is not circular. Sensor plate ( 1 ; 1' ) according to one of the preceding claims, wherein two main webs ( 60 . 61 ) are arranged opposite each other and further at least two side webs ( 62 . 63 . 64 . 65 ) are arranged opposite and offset by 90 ° to the main webs. Sensor plate ( 1 ; 1' ) according to the preceding claim, wherein the two main webs ( 60 . 61 ) are trapezoidal. Sensor plate ( 1 ; 1' ) according to any one of the preceding claims, wherein the sensors ( 70 ) Comprise strain gauges. Sensor plate ( 1 ; 1' ) according to the preceding claim, wherein the strain gauges in the region of the smallest cross section at the webs ( 60 . 61 ) are arranged. Sensor plate ( 1 ; 1' ) according to one of the preceding claims 6 or 7, wherein at least two strain gauges per web ( 60 . 61 . 62 . 63 . 64 . 65 ) are provided, which on opposite surfaces of the respective web ( 60 . 61 . 62 . 63 . 64 . 65 ) are arranged, and wherein preferably four strain gauges are provided per web, which are arranged in pairs on opposite faces of the web. Sensor plate ( 1 ; 1' ) according to one of the preceding claims 6 to 8, wherein the strain gauges on at least one web ( 60 . 61 . 62 . 63 . 64 . 65 ) are set up as a full bridge. Sensor plate ( 1 ; 1' ) according to one of the preceding claims, wherein the sensor plate at least one blocking agent ( 81 ) for limiting the relative movement of the two attachment regions to each other. Sensor plate ( 1 ; 1' ) according to the preceding claim, wherein the at least one blocking agent ( 81 ) is preferably designed as a pin, which in aligned bores ( 80 . 82 ) in the first ( 40 ) and second ( 50 ) Mounting area is inserted and away from the bore ( 80 ) in the first attachment area ( 40 ) into the hole ( 82 ) in the second attachment area ( 5o ). Sensor plate ( 1 ; 1' ) according to one of the preceding claims, wherein a fastening region ( 40 ) is annular and the other ( 50 ) is arranged inside the ring shape and wherein the webs ( 60 . 61 . 62 . 63 . 64 . 65 ) the two attachment areas ( 40 . 50 ) in the manner of wheel spokes, wherein at least two opposing webs ( 62 . 63 ; 64 . 65 ) have a rectangular cross-section which is constant in the radial direction. Sensor plate ( 1 ; 1' ) according to the preceding claim, wherein the height h of the rectangular cross section in the direction orthogonal to the main plane of the sensor plate is at least five times larger than the width b of the rectangular cross section, more preferably at least eight times larger than the width b and even more preferably at least ten times larger than that Width b is. Sensor plate ( 1 ; 1' ) according to one of the preceding claims 12 or 13, wherein at least two further opposing webs ( 60 . 61 ) are provided with a trapezoidal cross-section, offset by 90 ° to the at least two opposite webs ( 62 . 63 ; 64 . 65 ) are arranged with a rectangular cross section, wherein the cross section of the two further webs ( 60 . 61 ) tapers in the radial direction. Manipulator system comprising a manipulator ( 10 ) and a sensor plate ( 1 ; 1' ) according to one of the preceding claims, wherein the sensor plate on the manipulator ( 10 ) is fixed between manipulator ( 10 ) and manipulator socket ( 12 ) or between manipulator ( 10 ) and end effector. Manipulator system according to claim 15, wherein the pedestal ( 12 ) is movably arranged, preferably on a linear axis ( 14 ). Manipulator system according to claim 15 or 16, wherein one of the attachment areas ( 40 ) the other attachment area ( 50 ), and wherein the manipulator socket ( 12 ) on the interior ( 50 ) of the two attachment areas is attached and the manipulator ( 10 ) at the other attachment area ( 40 ).

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