DE202016008711U1 - load sensor - Google Patents

Abstract

Load sensor (40) for measuring mechanical loads, comprising a frame (41) and a first measuring system (10) comprising: optical transmitting means (13) for transmitting, in particular generating, deflecting and / or dividing, measuring light; andan optical receiving means (14) for detecting an incident position of incident measuring light from the transmitting means (13), the transmitting means (13), the receiving means (14) and / or at least one optical deflecting means (150, 152) for deflecting measuring light from the transmission means (13), which is arranged in a beam path (12) between transmitting and receiving means, is arranged on a structure which is elastically deformable by a load to be measured, in particular support (11), of the frame, wherein a measuring system (10, 20, 30) has a frame-fixed reference light emitting means (160, 13 ') for transmitting reference light to the receiving means (14) of the measuring system, wherein the measuring system is arranged such that a reference position of the reference light incident on the receiving means (14) by elastic deformation of at least one Structure is less changed than the impact due to the load to be measured in at least one reference load direction (x) position of incident measuring light from the transmitting means (13).

Description

The present invention relates to a load sensor for measuring mechanical loads, a robot assembly having the load sensor and a method for measuring mechanical loads by means of the load sensor.

Load sensors are used in particular on robots in order to measure loads acting on the robots, for example from environmental contacts, in particular collisions, or the like.

In this case, elastic deformations of the load sensor are measured as a result of the loads acting on it. For a good measurement resolution and / or a large measurement range, therefore, large deformations are advantageous.

On the other hand, such deformations affect the stability of, for example, a robot arranged on a load sensor. Conversely, for a good stability, small deformations or a high rigidity of the load sensor are advantageous.

The object of the present invention is to improve the measurement of loads, in particular of a robot arrangement.

This object is achieved by a load sensor having the features of claim 1. Claim 14 protects a robot assembly with a load sensor described herein. The subclaims relate to advantageous developments.

According to one embodiment of the present invention, a load sensor for measuring mechanical loads comprises a frame and a first measuring system, which comprises an optical transmission means for transmitting, in particular for generating, deflecting and / or dividing, measuring light and an optical receiving means for detecting an impact position of incident Measuring light from the transmitting means has.

In one embodiment, a mechanical load may include, in particular, forces and / or torques in one or more, in particular three, directions. Accordingly, the load sensor in one embodiment is a force and / or (rotary) torque (en) sensor, in particular a multi, especially six-axis, sensor.

In one embodiment, the transmitting means is arranged on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured, in particular is deformed or is provided or designed for this purpose.

Additionally or alternatively, in one embodiment, the receiving means on a structure, in particular support, of the frame is arranged, which is elastically deformable by a load to be measured, in particular is deformed or provided for this purpose or is formed.

Additionally or alternatively, in one embodiment, the first measuring system on at least one optical deflection means for deflecting measuring light from the transmitting means, which is arranged in a beam path (the measuring light) between the transmitting and receiving means. In one development, this is arranged on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured, in particular is deformed or is provided or designed for this purpose.

In addition, as stated above, the transmitting and / or receiving means (respectively) can be arranged on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured, in particular deformed or provided for this purpose . is trained. Equally, the transmitting and / or the receiving means can also, at least substantially, be arranged outside a force flow of a load to be measured or arranged and / or configured such that they are not moved, at least substantially, by the load to be measured.

In this way, in each case a kind of "optical lever" is realized which amplifies an elastic deformation of the structure (s), in particular support (s), via the optical path between the (respectively) connected optical element and a further one of the optical elements. In this way, in one embodiment, advantageously, a measurement accuracy and / or a measurement range and / or a stiffness of the load sensor can be increased.

In one embodiment, the load sensor has one or more, in particular at least two, further measuring systems which each have an optical transmission means for transmitting, in particular generating, deflecting and / or dividing, measuring light, and an optical receiving means for detecting an impact position of impinging Have measuring light from the transmitting means.

In one embodiment, the transmitting means is one or more of further measuring systems (each) on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured, in particular is deformed or is provided or designed for this purpose.

Additionally or alternatively, in one embodiment, the receiving means of one or more of the other measuring systems (each) on a structure, in particular support, of the frame is arranged, which is elastically deformable by a load to be measured, in particular is deformed or provided for this purpose or is formed ,

Additionally or alternatively, in one embodiment, one or more of the further measuring systems (each) at least one optical deflection means for deflecting measuring light from the transmitting means, which is arranged in a beam path (the measuring light) between the transmitting and receiving means of this measuring system. In one development, this is arranged on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured, in particular is deformed or is provided or designed for this purpose.

In addition, as described above, the transmitting and / or the receiving means of this measuring system (each) on a structure, in particular support, of the frame may be arranged, which is elastically deformable by a load to be measured, in particular is deformed or thereto is trained. Similarly, as stated above, the transmitting and / or receiving means of this measuring system (respectively) also, at least substantially, arranged outside a force flow of a load to be measured or arranged and / or formed so that they, at least substantially , are not moved by the load to be measured.

As a result, multiaxial loads can be measured in one embodiment.

In one embodiment, the first measuring system and one or more of the further measuring systems are configured and arranged relative to one another such that the beam path of the measuring light of the first measuring system and the beam path of the measuring light of the further measuring system or of the further measuring systems intersect, in particular cross over one another or not cut or cross or cut. In one embodiment, the beam path of the measuring light of the first measuring system and the beam path of the measuring light of the further measuring system or of the further measuring systems are not parallel to one another, wherein in one development the beam path of the measuring light of the first measuring system and the beam path of the measuring light of at least one further measuring system are not but (each) have a point of minimum distance from each other, and / or the beam path of the measuring light of the first measuring system and the beam path of the measuring light of at least one other measuring system intersect at an intersection, in one embodiment, these points minimum distance or this intersection lie within the load sensor.

As a result, in one embodiment, the optical paths or "lever" can be advantageously extended.

In one embodiment, the first measuring system and the other measuring systems are distributed equidistantly along a circumference of the frame, in particular three measuring systems each offset by 120 ° from each other.

As a result, multiaxial loads can advantageously be measured in one embodiment.

In one embodiment, the first and at least two of the further measuring systems can advantageously be used to measure in three translational and three rotational directions or a six-axis load state. In one embodiment, the load sensor in addition to the first measuring system on at least three of the other measuring systems. As a result, a redundant measurement can advantageously take place and / or the measurement accuracy can be increased by averaging.

In one embodiment, one or more measuring systems, in particular the first measuring system and / or one or more of the further measuring systems, each have one or more optical deflecting means for deflecting measuring light from the transmitting means of the measuring system, which are designed and arranged in one beam path. the measuring light) are arranged between transmitting and receiving means of the measuring system, that they a shift of the position of incidence of incident measuring light from the transmitting means, in particular on the receiving means of the measuring system, due to the elastic deformation of at least one structure, in particular support, of the frame as a result of the load to be measured, increase.

As a result, in one embodiment, a measurement accuracy and / or a measuring range can be (further) advantageously increased.

One or more of these deflecting means may be arranged (respectively) on a structure, in particular a support, of the frame, which is elastically deformable by a load to be measured, in particular is deformed or is provided or designed for this purpose, or be an aforementioned deflection means. Additionally or alternatively, the displacement of the impact position of incident measuring light from the transmitting means at the receiving means of the measuring system, which is increased by this (s) deflection (also) from the elastic deformation of a structure, in particular support, of the frame due to the load to be measured result, at which the transmitting means and / or the receiving means and / or one or more further optical deflection means of the corresponding measuring system are arranged. Accordingly, in one embodiment, one or more of these deflecting means for increasing the displacement of the impact position also (at least) arranged, at least substantially, outside a force flow of a load to be measured or arranged and / or formed so that they, at least substantially, not be moved by the load to be measured.

In one embodiment, one or more of the deflecting means of the first measuring system and / or one or more of the further measuring systems has (in each case) a, in particular flat, concave or convex mirror surface for reflecting measuring light from the transmitting means of the measuring system. Additionally or alternatively, in one embodiment, one or more of the deflection means of the first measuring system and / or one or more of the other measuring systems (each) a lens, in particular a diverging or converging lens, for breaking measurement light from the transmitting means of the measuring system. As a result, in one embodiment, the displacement of the impact position can advantageously be increased.

In one embodiment, the mirror surface of one or more of the deflecting means forms with the beam path of the measuring light of the corresponding measuring system (respectively) an angle which (in terms of magnitude) is less than 60 °, in particular less than 45 °, in particular less than 30 °, in particular less than 20 °, and / or greater than 5 °. By such, in particular flat, reflection, the displacement of the impact position can advantageously be increased in one embodiment.

Additionally or alternatively forms in one embodiment, the mirror surface of one or more of the deflection with the beam path of the incident thereon measuring light of the corresponding measuring system (respectively) an angle (magnitude) greater than 45 °, in particular greater than 60 °, and / or less than 90 °, in particular less than 85 °, is. By such, in particular steep or direct reflection, in one embodiment, in particular a multiple forward and return line between mutually facing mirror surfaces can be promoted.

In one embodiment, at least two mirror surfaces of the first measuring system and / or one or more of the other measuring systems (each) are arranged opposite each other so that measuring light is reflected several times between them or the beam path reciprocates repeatedly between them.

In one embodiment, one or more measuring systems, in particular the first measuring system and / or one or more of the further measuring systems, (in each case), in particular frame-fixed, reference light emitting means for transmitting, in particular generating, deflecting and / or dividing, reference light to the receiving means of Measuring system, wherein the measuring system is designed such that a reference position of, in particular on the receiving means incident reference light by an elastic deformation of at least one of the structure (s), in particular support (s) of the measuring system as a result of the load to be measured in one or more reference load directions, in particular by a bending of the structure (s), in particular support (s), in one or two directions, less than the impact position of incident measuring light from the transmitting means by this elastic deformation, in particular - at least substantially - by the elastic deformation of the strukt ur (en), in particular support (s), by which the impact position of incident measuring light is displaced on the receiving means is not changed. In particular, in one embodiment, the measuring system is designed such that a reference position of, in particular, the reference light incident on the receiving means by a load to be measured in one or more reference load directions is less changed than the impact position of incident measuring light from the transmitting means by this load to be measured , In particular - at least substantially - is not changed by the load to be measured, by which the impact position of incident measuring light is shifted on the receiving means.

In one embodiment, the measuring system or systems (each) are designed such that a relative position of impact and reference position on the receiving means at load-free sensor, in particular when heating the load-free sensor from 20 ° C to 30 ° C, in particular 40 ° C. is at least substantially constant.

In one embodiment, influences of deformations other than those induced by the load to be measured can thereby be reduced, preferably-at least substantially-eliminated or compensated, in particular thermal deformations: a reference is available with the reference position of reference light incident on the receiving means deformations other than those induced by the load to be measured, at least substantially, "participate", so that a difference between the impact and the reference position is at least partially, in particular at least substantially, preferably exclusively, induced by the load to be measured or is conditional.

In a further development, this is a beam path of the reference light on one or several, in particular all, optical elements of the measuring system passed, which are arranged on a by the load to be measured elastically deformable structure, in particular support, of the frame or are moved by a load to be measured.

In another development, the measuring system for this purpose is designed so that a beam path of the reference light by elastic deformation of the structure (s), in particular support (s), as a result of the load to be measured in a reference load direction is less deflected as a beam path of the measuring light of the measuring system , in one embodiment by this deformation - at least substantially - is not deflected.

In particular, a measuring system can be designed such that a load to be measured in a first reference load direction of a structure, in particular support, bends, at least substantially, in one direction, in particular a main direction of the structure, in particular support, and this is a corresponding displacement of the impact position the measuring light causes, but - at least substantially - no shift of the reference position. In one embodiment, this can be effected, in particular, by reference light and measuring light being respectively reflected by a mirror surface on the structure, in particular support, the mirror surface, which reflects reference light, being oriented at least substantially parallel to the reference load and / or bending direction while the mirror surface which reflects measurement light forms with the reference load and / or bend direction a non-zero angle, which in one embodiment is at least 30 ° and / or at most 60 °. This causes a deformation, in particular bending, of the structure, in particular support, due to a load in the first reference loading direction by an associated movement of the oblique mirror surface a significant (re) displacement of the impact position, while the associated movement of the parallel mirror surface, the reference position, at least essentially, leaves unchanged.

Generally, in one embodiment, at least one optical deflection element of at least one measuring system, which is arranged on a structure, in particular support, of the frame, which is elastically deformable by a load to be measured in a first reference loading direction, in particular deformed or provided for this purpose or formed is, two mutually angled mirror surfaces, of which a first in the beam path of the measuring light and the other or second in the beam path of the reference light of the measuring system are arranged, wherein in a development to be measured load in the first reference load direction, at least substantially, a tilt the first mirror surface and a displacement of the second mirror surface parallel to the second mirror surface causes or induced.

In one embodiment, the beam path of the measuring light and the beam path of the reference light run through one or more common beam splitters. As a result, the same light source for measuring light and reference light can advantageously be used in one embodiment and / or measuring light and reference light can be brought together again before impinging on the receiving means, thereby reducing a detection area of the receiving means and / or improving the compensation. In one embodiment, a beam splitter can have, in particular, at least one semitransparent mirror.

In one embodiment, one or more measuring systems, in particular the first measuring system and / or one or more of the further measuring systems, are (each) designed such that the reference position of reference light incident on the receiving means by an elastic deformation of the structure (s), in particular support (n), as a result of the load to be measured in a further or second, in particular to one or first reference load direction perpendicular reference load direction is changed more than the impact position of incident measuring light from the transmitting means, wherein in a further development, the measuring system is formed so an optical path of the measuring light is deflected less by an elastic deformation of the structure (s), in particular support (s), as a result of the load to be measured in the further or second reference loading direction than a beam path of the reference light of the measuring system, in one embodiment by this deformation - little at least essentially - not diverted.

Thus, in one embodiment, light may simultaneously function as the measurement light for the one (first) reference loading direction and the reference light for the further (second) reference loading direction, and vice versa for further light simultaneously as reference light for the one (first) reference loading direction and as measuring light for the further (second) reference load direction.

This can be realized, in particular, by the embodiment explained above with two mutually angled mirror surfaces: a load to be measured in one reference load direction causes, at least substantially, a tilt of the first mirror surface and a displacement of the second mirror surface parallel to the second mirror surface, while a load to be measured in the other reference loading direction, at least in Essentially, a displacement of the first mirror surface parallel to the first mirror surface and a tilting of the second mirror surface causes or induced.

In one embodiment, measuring and reference light of at least one measuring system emanate from a common light source or two light sources, which are designed and arranged such that their relative position to one another is not changed, at least substantially, by a load of the load sensor to be measured.

A receiving means for detecting an impact and reference position may be integrally formed in one embodiment or have a common surface for detecting the impact and reference position. Similarly, it may be formed in several parts or have a surface for detecting the impact position and another surface for detecting the reference position, then in a development, the two surfaces are formed and arranged such that their relative position to each other by a load to be measured of the load sensor, at least in essence, not changed.

In one embodiment, measuring and / or reference light of one or more measuring systems, in particular of the first measuring system and / or one or more of the further measuring systems, are (in each case) laser light. As a result, in one embodiment, the precision of the measurement can be improved.

In one embodiment, the receiving means of one or more measuring systems, in particular of the first measuring system and / or one or more of the further measuring systems, is (each) adapted to detect a shift of a position of incident light in at least two directions. In one embodiment, the receiving means may include, in particular, a CCD camera. As a result, multiaxial loads can advantageously be measured in one embodiment.

In one embodiment, a robot arrangement comprises a robot, in particular a robot with a payload of at least 25 kg, and a load sensor described here, on which a base of the robot is supported. As a result, advantageously, a stability of the robot can be increased and / or loads acting on the robot can be measured with high measuring accuracy and / or over a large measuring range.

In one embodiment, positions of, in particular automatically, the receiving means of one or more of the measuring systems incident light is detected and therefrom one, in particular multiaxial, load of the load sensor determined: a load of the load sensor causes an elastic deformation of one or more of its structures , In particular columns, and thus a shift of the impact position in one or more of its measuring systems, from which or then the load of the load sensor can be determined.

For this purpose, the load sensor can be calibrated or be in a development, for example, by successive impressing forces and / or (rotational) moments in different height or size and / or in different directions, and assignment, in particular storage, the thereby detected (shifts the) impact position (s).

In one embodiment, at least one detected impact position based on the reference position is error-compensated, in particular temperature-compensated, in particular by the load being determined on the basis of a relative displacement of the impact position relative to the reference position.

In one embodiment, one or more of the structures mentioned here, in particular supports, are designed as cantilevered beams which are arranged on a flange of the frame and, apart from this connection, are spaced from the rest of the frame. As a result, in one embodiment, an advantageous elastic deformation can be realized.

In one embodiment, one or more of the structures mentioned here, in particular supports, are provided for forwarding, in particular inlet or outlet, of loads to be measured or designed or arranged in a force flow to be measured. In one development, one or more of the structures mentioned here, in particular supports, have interfaces to, in particular, non-destructively detachable or non-destructively detachable, in particular material-locking, attachment of the load sensor to a measuring surface, in particular bores, bolts, couplings or the like. In one embodiment, a measuring surface of an arrangement on which loads are to be measured, in particular the robot base, in particular only, on one or more of the structures mentioned here, in particular supports, one or more of the measuring systems mentioned here, in particular non-destructive detachable or not non-destructively detachable, in particular cohesively, attached.

In one embodiment, the load sensor has an evaluation unit for determining a, in particular multiaxial, load of the load sensor from detected positions at the receiving means incident measuring light and in a development reference light, which is adapted to carry out a method described herein and / or means for error, in particular temperature compensation, at least one detected impact position based on an associated reference position, in particular for determining the load based on a relative displacement of the impact - With respect to the reference position, has.

As already mentioned above, transmission of (measuring or reference) light in the present case is understood as both generating and deflecting or dividing light, since an optical element which deflects or divides incident light also serves as the optical system (new) light source can be considered. For example, a beam splitter or mirror as well as a light source may each be a transmitting means in the sense of the present invention. A deflection of (measurement or reference) light in the present case is understood in particular to be an alteration of a beam path of light, in particular a reflection or a break of light.

• 1: eine Roboteranordnung nach einer Ausführung der vorliegenden Erfindung;
• 2: einen Schnitt längs der Linie II-II in 1;
• 3: einen Schnitt längs der Linie III-III in 2;
• 4: einen 3 entsprechenden Schnitt nach einer weiteren Ausführung der vorliegenden Erfindung;
• 5: einen Strahlengang eines Messsystems eines Lastsensors nach einer weiteren Ausführung der vorliegenden Erfindung;
• 6: einen 3, 4 entsprechenden Schnitt nach einer weiteren Ausführung der vorliegenden Erfindung; und
• 7: einen Schnitt längs der Linie VII-VII in 6.

Further advantages and features emerge from the subclaims and the exemplary embodiments. This shows, partially schematized:

• 1 a robot assembly according to an embodiment of the present invention;
• 2 : a section along the line II - II in 1 ;
• 3 : a section along the line III - III in 2 ;
• 4 : one 3 corresponding section according to another embodiment of the present invention;
• 5 a beam path of a measuring system of a load sensor according to another embodiment of the present invention;
• 6 : one 3 . 4 corresponding section according to another embodiment of the present invention; and
• 7 : a section along the line VII - VII in 6 ,

1 shows a robot assembly according to an embodiment of the present invention with a robot 100 whose base 110 at three supports 11 . 21 . 31 of three measuring systems 10 . 20 . 30 a load sensor 40 are bolted.

2 shows in a section along the line II - II a plan view of the load sensor 40 in which one is his frame 41 and the three each offset by 120 ° measurement systems 10 . 20 . 30 recognizes, in particular their supports 11 . 21 . 31 and dash-dotted lines indicated measuring light beam paths 12 . 22 . 32 ,

3 shows in a section along the line III - III a cross section through the first measuring system 10 , The other two measuring systems 20 . 30 are identically constructed, so that to this on the description of the first measuring system 10 Reference is made.

The first measuring system 10 has an optical transmission means 13 for transmitting measuring light in the form of a laser beam and an optical receiving means in the form of a CCD camera 14 for detecting an impact position of incident measuring light from the transmitting means 13 on.

Transmitter and receiver are together on the support 11 of the frame 41 arranged, which is elastically deformable by a load to be measured, in particular is deformed or provided for this purpose or is formed.

In addition, the first measuring system 10 an optical deflection means in the form of a flat mirror surface 150 for deflecting measuring light from the transmitting means 13 on, the or in the dash-dotted lines indicated beam path 12 the measuring light is arranged between the transmitting and receiving means and with the beam path 12 of the incident measuring light forms an angle which is greater than 60 °.

A burden on the robot 100 is beyond its basis 110 in the three supports 11 . 21 . 31 initiated. Accordingly, the supports deform due to a load to be measured of the load sensor. As a result, an impact position of measurement light shifts from the transmission means 13 at the receiving means 14 , Due to the reflection on the mirror surface 150 the optical path is extended and the displacement is advantageously increased.

An evaluation unit 50 receives from the receiving means of the three measuring systems 10 . 20 . 30 Detect impact positions or their displacements and from this determines the six-axis load, ie that of the robot base 110 on the supports 11 . 21 . 31 exerted forces and moments.

4 shows one 3 corresponding section according to another embodiment of the present invention. Corresponding features are identified by identical reference numerals, so that reference is made to the above description and will be discussed below only differences.

In the execution of 4 conversely, only the mirror surface is 150 on the prop 11 of the measuring system 10 arranged, which is elastically deformable by the load to be measured, in particular is deformed or provided for this purpose or is formed. Transmitting and receiving means 13 . 14 are in the execution of 4 arranged substantially outside the force flow of the load to be measured or arranged and designed so that they are not moved by the load to be measured.

In addition, the measuring system in the execution of the 4 a further optical deflection means in the form of a second mirror surface 151 on, with the beam path 12 of the measuring light incident thereon forms an angle α which is smaller than 45 ° and, due to this flat reflection, the displacement of the impact position at the receiving means 14 further enlarged.

One recognizes on average the 2 that the first measuring system 10 and the two other measuring systems 20 . 30 so formed and equidistant along a circumference of the frame 41 are distributed, that their beam paths 12 . 22 . 32 to cross each other.

In 3 . 4 are each variations indicated by dashed lines. So can the mirror surface 150 each also a concave (see. 3 ) or convex (cf. 4 ) Mirror surface 152 be.

Additionally or alternatively, in the beam path 12 in each case further optical deflecting means may be arranged in order to shift the impact position of incident measuring light from the transmitting means 13 at the receiving means 14 which is due to the elastic deformation of the support 11 of the frame 41 as a result of the load to be measured results in increasing.

Exemplary are in this 3 dashed a diverging lens 153 and a condenser lens 154 indicated. In 4 Dashed is another mirror surface 155 for multiple reflection of measuring light with the mirror surface 150 indicated.

5 shows the beam path 12 of the measuring system 10 according to another embodiment of the present invention. Corresponding features are again identified by identical reference numerals, so that reference is made to the above description and will be discussed below only differences.

One recognizes the transmission means described above 13 and receiving means 14 , how, too 4 explained, are arranged substantially outside the force flow of the load to be measured or arranged and designed so that they are not moved, at least substantially, by the load to be measured. This is in 5 each indicated by an obliquely hatched fixed reference plane. You can also see the mirror surface 150 on the prop 11 of the measuring system 10 is arranged (see. 4 ), which is elastically deformable by the load to be measured, in particular is deformed or is provided or designed for this purpose.

In addition, the execution of the 5 a frame-fixed reference light emitting means in the form of a beam splitter in the form of a semitransparent mirror 160 for transmitting reference light to the receiving means 14 of the measuring system 10 on. This reference light is provided by another frame-fixed mirror 161 in another beam splitter in the form of a semipermeable mirror 162 deflected, in which it again together with the measuring light and to the receiving means 14 is continued. The beam path of the reference light is in 5 With 12 ' designated. The beam splitters 160 . 162 as well as the mirror 161 are each as well as sending means 13 and receiving means 14 arranged outside the force flow of the load to be measured or designed so that they are not moved, at least substantially, by the load to be measured. This too is in 5 indicated by an obliquely hatched fixed reference plane.

Thus, the beam path 12 ' of the reference light on the optical element 150 of the measuring system 10 passed, the at the elastically deformable by the load to be measured support 11 of the frame 41 is arranged.

The measuring system is corresponding 10 the execution of 5 formed such that a reference position of at the receiving means 14 incident reference light by a (elastic deformation of the support 11 of the measuring system 10 is not changed as a result of the load to be measured in contrast to the impact position of the measuring light, while at the same time a relative position of impact and reference position at the receiving means 14 at load-free sensor, in particular when heating the load-free sensor, is at least substantially constant or remains.

6 shows one 3 . 4 corresponding section according to another embodiment of the present invention, 7 a section along the line VII - VII in 6 , Corresponding features are again identified by identical reference numerals, so that reference is made to the above description and will be discussed below only differences.

In the execution of 6 . 7 has an optical deflecting element of the measuring system 10 two mutually angled mirror surfaces 150 . 156 on, of which the first mirror surface 150 in the beam path 12 of the measuring light and the other or second mirror surface 156 in the beam path 12 ' the reference light of the measuring system 10 is arranged.

A load to be measured in an in 6 vertical (first) reference loading direction x causes due to a bending of the beam 11 in its one main direction, a tilting of the first mirror surface 150 and a displacement of the second mirror surface 156 parallel to the second mirror surface.

Conversely, a load to be measured in a perpendicular thereto further, corresponding in 7 vertical (second) reference loading direction y due to a bending of the beam 11 in its other main direction a tilt of the second mirror surface 156 and a displacement of the first mirror surface 150 parallel to the first mirror surface.

Thus, light of a beam path acts 12 respectively. 12 ' each simultaneously as a measuring light for measuring loads in one of the two reference load directions x . y and as a reference light for compensation in measuring loads in the other of the two reference load directions.

Accordingly, for example, the beam path 12 ' the reference light by an elastic deformation of the support 11 due to the load to be measured in the one reference load direction x (vertically in 6 ) less deflected than the beam path 12 the measuring light of the measuring system.

In the execution of 6 . 7 go measuring and reference light from two light sources 13 . 13 ' from, which are designed and arranged such that their relative position to each other by a load to be measured of the load sensor, at least substantially, is not changed.

The robot 100 has a payload of at least 25 kg.

The evaluation unit 50 automatically determines from the positions of at the receiving means 14 the measuring systems 10 . 20 . 30 incident measuring and possibly reference light a multi-axis load of the load sensor 40 ,

The detected impact positions or their shifts on the basis of the associated detected reference positions are faulty, in particular temperature compensated, by determining the load on the basis of a relative displacement of the impact relative to the respective reference positions.

The pillars 11 . 21 . 31 are designed as cantilevered beams, which are connected to an annular flange of the frame 41 are arranged and spaced apart from the rest of the frame except for this connection.

The robot base 110 is, in the embodiments by indicated screws 60 , only on the three supports 11 . 21 . 31 of the three measuring systems 10 . 20 . 30 non-destructively attached.

Although exemplary embodiments have been explained in the foregoing description, it should be understood that a variety of modifications are possible. It should also be noted that the exemplary embodiments are merely examples that are not intended to limit the scope, applications and construction in any way. Rather, the expert is given by the preceding description, a guide for the implementation of at least one exemplary embodiment, with various changes, in particular with regard to the function and arrangement of the components described, can be made without departing from the scope, as it turns out according to the claims and these equivalent combinations of features.

LIST OF REFERENCE NUMBERS

10

first measuring system

11

support

12

Measuring light beam path

12 '

Reference light beam path

13, 13 '

transmitting means

14

receiving means

20, 30

another measuring system

21, 31

support

22.32

Measuring light beam path

40

load sensor

41

frame

50

evaluation

60

screw

100

robot

110

Base

150, 151, 152

Mirror (surface) (deflection)

153

Diverging lens (deflection)

154

Converging lens (deflection)

155, 156

Mirror (surface) (deflection)

160, 162

beamsplitter

161

Mirror (surface) (deflection)

Claims (14)

Load sensor (40) for measuring mechanical loads, comprising a frame (41) and a first measuring system (10) with: an optical transmission means (13) for transmitting, in particular generating, deflecting and / or dividing, measuring light; and an optical receiving means (14) for detecting an incident position of incident measuring light from the transmitting means (13); wherein the transmitting means (13), the receiving means (14) and / or at least one optical deflection means (150, 152) for deflecting measuring light from the transmitting means (13) in a beam path (12) between transmitting and Receiving means is arranged, on a by a load to be measured elastically deformable structure, in particular support (11), of the frame is arranged, wherein a measuring system (10, 20, 30) comprises a frame-fixed reference light emitting means (160, 13 ') for transmitting reference light to the receiving means (14) of the measuring system, the measuring system being designed such that a reference position is obtained at the receiving means (14). incident reference light is changed by an elastic deformation of at least one structure due to the load to be measured in at least one reference load direction (x) less than the impact position of incident measuring light from the transmitting means (13). Load sensor (40) after Claim 1 characterized by at least one further measuring system (20, 30) comprising: optical transmitting means (13) for transmitting, in particular generating, deflecting and / or dividing, measurement light; and optical receiving means (14) for detecting an incident position of incident measuring light from the transmitting means (13); wherein the transmitting means (13), the receiving means (14) and / or at least one optical deflecting means (150, 152) for deflecting measuring light from the transmitting means (13) arranged in a beam path (22, 32) between the transmitting and receiving means is, on a by a load to be measured elastically deformable structure, in particular support (21, 31), of the frame (41) is arranged. Load sensor (40) after Claim 2 , wherein the beam path (12) of the measuring light of the first measuring system (10) and the beam path (22, 32) of the measuring light of the at least one further measuring system (20, 30) intersect each other. Load sensor (40) according to one of the preceding claims, wherein at least one measuring system (10, 20, 30) has at least one optical deflecting means (150-155) for deflecting measuring light from the transmitting means (13) of the measuring system, which is designed and arranged in one Beam path (12, 22, 32) is arranged between the transmitting and receiving means of the measuring system that there is a shift of the position of incidence of incident measuring light from the transmitting means (13) to the receiving means (14) of the measuring system due to the elastic deformation of at least one structure, in particular Support (11, 21, 31), the frame (41) increased as a result of the load to be measured. Load sensor (40) after Claim 4 wherein the deflection means has a, in particular flat, concave or convex mirror surface (150, 151, 152, 155) for reflecting measuring light from the transmitting means (13) of the measuring system or a lens, in particular a diverging or converging lens (153, 154) , for breaking measuring light from the transmitting means (13) of the measuring system. Load sensor (40) after Claim 5 in that the mirror surface (150; 151) forms, with the beam path (12) of the incident measuring light, an angle (α) which is greater than 45 ° or less than 60 °. A load sensor (40) according to any one of the preceding claims, wherein the reference light emitting means (160; 13 ') is arranged to generate, deflect and / or split reference light to the measuring system receiving means (14). Load sensor (40) after Claim 7 in which a beam path (12 ') of the reference light is applied to at least one optical element (150) of the measuring system (10, 20, 30), which has a structure elastically deformable by the load to be measured, in particular support (11, 21, 31), the frame (41) is arranged, is guided past or by an elastic deformation of the at least one structure, in particular support (11, 21, 31), as a result of the load to be measured in a reference load direction (x) less deflected than a beam path (12) the measuring light of the measuring system. Load sensor (40) after Claim 7 or 8th , wherein the beam path (12) of the measuring light and the beam path (12 ') of the reference light extend through at least one common beam splitter (160, 162). Load sensor (40) according to one of Claims 7 to 9 wherein the measuring system (10, 20, 30) is formed such that the reference position of the reference light incident on the receiving means (14) by an elastic deformation of the structure, in particular support (11, 21, 31), due to the load to be measured in another Reference load direction (y) is changed more than the impact position of incident measuring light from the transmitting means (13). Load sensor (40) according to one of the preceding claims, wherein the measuring and / or reference light of at least one measuring system (10, 20, 30) is laser light. A load sensor (40) according to any one of the preceding claims, wherein the receiving means (14) of at least one measuring system (10, 20, 30) is adapted to detect a displacement of a position of incident light in at least two directions. Load sensor (40) according to one of the preceding claims, characterized by an evaluation unit (50) for determining a, in particular multiaxial, loading of the load sensor (40) from detected positions at the receiving means (14) of at least one measuring system (10, 20, 30). incident light. Robot assembly comprising a robot (100), in particular a robot with a payload of at least 25 kg, and a load sensor (40) according to any one of the preceding claims, on which a base (110) of the robot is supported.

Images