Patent Description:
Currently, a six-dimensional force sensor refers to a sensor which is configured to detect forces in directions of X, Y, and Z axes in space and force moments with respect to respective axes. In some examples, the principle of action of the six-dimensional force sensor is the resistance strain effect. A strain gauge is generally formed by wrapping a constantan grid filament on a substrate and attached to a location of an elastomer (i.e., force location) to obtain a force or a force moment by detecting a strain value of the strain gauge.

However, the strain gauge is connected to the elastomer (i.e., force location) by an adhesive layer, which results in mechanical errors such as creep, hysteresis, and drift (zero drift, temperature drift) in the sensor that affect the sensitivity of the sensor, thus affecting the detection sensitivity of the sensor. Related technologies are known from <CIT>, <CIT>, and <CIT>.

The present invention provides a strain sensor and a robot to solve the problem that the strain sensor in the related art has phenomena such as creep, hysteresis, and shift which affect the detection sensitivity thereof.

In some embodiments, the strain sensor includes a plurality of wire sets and a plurality of mounting structures. The plurality of wire sets are arranged along an inner circumference of the mounting recess and spaced from each other. The plurality of mounting structures are disposed correspondingly to the plurality of wire sets.

In some embodiments, the mounting structure is provided with a first winding part thereon. The first winding part includes a plurality of first protrusions arranged in at least one of a first pre-defined direction and a second pre-defined direction and spaced from each other. The first protrusions are provided with first wire passing holes configured to allow the wire set to pass therethrough. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween.

In some embodiments, the bearing structure is provided with a second winding part thereon. The second winding part includes a plurality of second protrusions arranged in at least one of a first pre-defined direction and a second pre-defined direction and spaced from each other. The second protrusions are provided with second wire passing holes configured to allow the wire set to pass therethrough. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween.

In some embodiments, the strain sensor further includes a cover covering the base and the bearing structure. The bearing structure includes: a bearing body connected to and engaged with the cover; and a winding body connected to the bearing body and located at a side of the bearing body away from the cover. The second winding part is disposed on an outer surface of the winding body.

In some embodiments, the winding body has a cross-section in shape of a polygon. There are a plurality of second winding parts. The plurality of second winding parts are disposed correspondingly to a plurality of sides of the polygon in a one-to-one manner.

In some embodiments, a surface of the bearing structure facing the cover is higher than a surface of the base facing the cover.

In some embodiments, a surface of the bearing structure facing the cover is flush with a surface of the base facing the cover.

In some embodiments, the mounting structure has a plate structure. The plate structure includes a first surface and a second surface opposite to the first surface. The first winding part is disposed on the first surface. The second surface is an arch-shaped surface. The pre-defined gap is formed between the second surface and the inner surface of the mounting recess.

In some embodiments, the wire set includes: a first wire sub-set including at least two first wire parts arranged in a first pre-defined direction and spaced from each other; and a second wire sub-set including at least two second wire parts arranged in a second pre-defined direction and spaced from each other. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween.

In some embodiments, there are a plurality of first wire sub-sets and a plurality of second wire sub-sets. The plurality of first wire sub-sets are arranged along an inner circumferential surface of the mounting recess and spaced from each other. At least one second wire sub-set is disposed between two adjacent first wire sub-sets.

In some embodiments, a ratio of a measuring range of the strain sensor to a length of the wire of the first wire part is less than or equal to <NUM>.

In some embodiments, a ratio of a measuring range of the strain sensor to a length of the wire of the second wire part is less than or equal to <NUM>.

In some embodiments, the strain sensor further includes a plurality of fixing structures disposed on the mounting structure. Ends of wires of the wire set wind on the fixing structures, so that the ends of the wires are fixed by the fixing structures.

A robot according to some embodiments of the present invention includes the above-described strain sensor.

In the above-described embodiments, the strain sensor includes the base, the mounting structure, the bearing structure, and the wire set. The base is provided with the mounting recess. The mounting structure is disposed on the base and located in the mounting recess. The pre-defined gap is formed between the mounting structure and the inner surface of the mounting recess. The bearing structure is mounted in the mounting recess and located outside the pre-defined gap. A side of the wire set is disposed on the bearing structure, and another side of the wire set is disposed on the mounting structure. In this way, the bearing structure is directly connected to the wire set. In the detection process using the strain sensor, the load is directly applied onto the wire set through the bearing structure to take maximum advantage of the resistance strain effect of the wire set, which makes the response of the strain sensor more sensitive, eliminates the affection of the creep and the hysteresis of an elastomer on the detection sensitivity of the strain sensor, and thus solves the problem that the strain sensor in the related art has phenomena such as creep, hysteresis, and shift which affect the detection sensitivity thereof, thereby increasing the detection sensitivity and the response speed of the strain sensor and also increasing the detection precision of the strain sensor.

The accompanying drawings, which constitute part of the present disclosure, are used to provide further understanding of the present disclosure, and exemplary embodiments of the present invention and the description thereof are used to explain the present invention and not intended to inappropriately limit the present invention In the drawings:.

<NUM>-base; <NUM>-mounting recess; <NUM>-mounting structure; <NUM>-predefined gap; <NUM>-first winding part; <NUM>-first protrusion; <NUM>-first wire passing hole; <NUM>-first surface; <NUM>-second surface; <NUM>-bearing structure; <NUM>-second winding part; <NUM>-secod protrusion; <NUM>-second wire passing hole; <NUM>-bearing body; <NUM>-winding body; <NUM>-wire set; <NUM>-first wire sub-set; <NUM>-first wire; <NUM>-second wire; <NUM>-fifth wire; <NUM>-sixth wire; <NUM>-ninth wire; <NUM>-tenth wire; <NUM>-thirteenth wire; <NUM>-fourteenth wire; <NUM>-second wire sub-set; <NUM>-third wire; <NUM>-fourth wire; <NUM>-seventh wire; <NUM>-eighth wire; <NUM>-eleventh wire; <NUM>-twelfth wire; <NUM>-fifteenth wire; <NUM>-sixteenth wire; <NUM>-cover; and <NUM>-fixing structure.

It should be noted that the embodiments and the features of the embodiments of the present invention may be combined with each other under the condition of no conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

It should be pointed out that unless otherwise defined, all the technical and scientific terms used herein have the same meaning as commonly understood by the person skilled in the art to which the present disclosure belongs.

In the present disclosure, unless otherwise stated, orientation terms such as "up" and "down" are usually used for directions shown in the drawings, or for vertical, perpendicular, or gravity directions. Similarly, for ease of understanding and description, "left" and "right" usually refer to left and right shown in the drawings; and "inside" and "outside" refer to inside and outside relative to the outline of each component itself. Those orientation terms are not intended to limit the present disclosure.

In order to solve the problem that the strain sensor in the related art has phenomena such as creep, hysteresis, and shift which affect the detection sensitivity thereof, a strain sensor and a robot are provided in embodiments of the present invention.

As shown in <FIG>, the strain sensor includes a base <NUM>, a mounting structure <NUM>, a bearing structure <NUM>, and a wire set <NUM>. The base <NUM> is provided with a mounting recess <NUM>. The mounting structure <NUM> is disposed on the base <NUM> and located in the mounting recess <NUM>. A pre-defined gap <NUM> is formed between the mounting structure <NUM> and an inner surface of the mounting recess <NUM>. The bearing structure <NUM> is mounted in the mounting recess <NUM> and located outside the pre-defined gap <NUM>. A side of the wire set <NUM> is disposed on the bearing structure <NUM>, and another side of the wire set <NUM> is disposed on the mounting structure <NUM>.

In this embodiment, the bearing structure <NUM> is directly connected to the wire set <NUM>. In the detection process using the strain sensor, the load is directly applied onto the wire set <NUM> through the bearing structure <NUM> to take maximum advantage of the resistance strain effect of the wire set <NUM>, which makes the response of the strain sensor more sensitive, eliminates the affection of the creep and the hysteresis of an elastomer on the detection sensitivity of the strain sensor, and thus solves the problem that the strain sensor in the related art has phenomena such as creep, hysteresis, and shift which affect the detection sensitivity thereof, thereby increasing the detection sensitivity and the response speed of the strain sensor and also increasing the detection precision of the strain sensor.

In this embodiment, the wire set <NUM> is formed by winding a wire on the bearing structure <NUM> and the mounting structure <NUM>.

In some embodiments, there are a plurality of wire sets <NUM> arranged along an inner circumference of the mounting recess <NUM> and spaced from each other. There are a plurality of mounting structures <NUM> arranged correspondingly to the plurality of wire sets <NUM>. In this way, in one hand, the above configuration ensures that the strain sensor is able to detect acting forces, force moments, or accelerated speeds in multiple directions, thereby widening the detection range of the strain sensor. In the other hand, the above configuration increases the detection sensitivity of the strain sensor.

In this embodiment, there are eight wire sets <NUM> arranged along the inner circumference of the mounting recess <NUM> and spaced from each other, and eight mounting structures <NUM> disposed correspondingly to the eight wire sets <NUM> in a one-to-one manner, so that the distribution of the wire sets <NUM> are more reasonable and compact, thereby decreasing the processing difficulty for the operator.

It should be noted that the number of the wire sets <NUM> is not limited herein and may be adjusted according to operating conditions. In some embodiments, the number of the wire sets <NUM> is four, six, ten, or twelve.

It should be noted that the number of the mounting structures <NUM> is not limited herein and may be adjusted according to operating conditions. In some embodiments, the number of the mounting structures <NUM> is four, six, ten, or twelve.

As shown in <FIG>, the mounting structure <NUM> is provided with a first winding part <NUM> thereon. The first winding part <NUM> includes a plurality of first protrusions <NUM> arranged in a first pre-defined direction and a second pre-defined direction and spaced from each other. The first protrusion <NUM> is provided with a first wire passing hole <NUM> configured to allow the wire set <NUM> to pass therethrough. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween. In some embodiments, the first pre-defined direction is perpendicular to the second pre-defined direction. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes <NUM> so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty.

In this embodiment, the first pre-defined direction is a height direction of the strain sensor, and the first wire passing hole <NUM> extends in the first pre-defined direction.

It should be noted that the arrangement direction of the plurality of first protrusions <NUM> is not limited herein and may be adjusted according to operating conditions. In other embodiments which are not shown in the drawings, the first winding part includes a plurality of first protrusions arranged in a first pre-defined direction and spaced from each other. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes, so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty.

In other embodiments which are not shown in the drawings, the first winding part includes a plurality of first protrusions arranged in a second pre-defined direction and spaced from each other. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes, so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty.

As shown in <FIG>, the bearing structure <NUM> is provided with a second winding part <NUM> thereon. The second winding part <NUM> includes a plurality of second protrusions <NUM> arranged in a first pre-defined direction and a second pre-defined direction and spaced from each other. The second protrusion <NUM> is provided with a second wire passing hole <NUM> configured to allow the wire set <NUM> to pass therethrough. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes <NUM> and the second wire passing holes <NUM>, so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty. In addition, the above configuration improves the structure stability of the wire set <NUM> and thus improves the detection stability and the operational reliability of the strain sensor.

In this embodiment, the second wire passing hole <NUM> extends in the first pre-defined direction.

It should be noted that the arrangement direction of the plurality of second protrusions <NUM> is not limited herein and may be adjusted according to operating conditions. In other embodiments which are not shown in the drawings, the second winding part includes a plurality of second protrusions arranged in a first pre-defined direction and spaced from each other. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes and the second wire passing holes, so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty.

In other embodiments which are not shown in the drawings, the first winding part includes a plurality of second protrusions arranged in a second pre-defined direction and spaced from each other. In this way, in the process of winding the wire by an operator, the wire passes through the first wire passing holes and the second wire passing holes, so that the fixation and the winding of the wire by the operator are easier and simpler, thereby decreasing the operating difficulty.

As shown in <FIG>, the strain sensor further includes a cover <NUM> covering the base <NUM> and the bearing structure <NUM>. The bearing structure <NUM> includes a bearing body <NUM> and a winding body <NUM>. The bearing body <NUM> is connected to and engaged with the cover <NUM>. The winding body <NUM> is connected to the bearing body <NUM> and located at a side of the bearing body <NUM> away from the cover <NUM>. The second winding part <NUM> is provided on an outer surface of the winding body <NUM>. In this way, as the bearing body <NUM> and the cover <NUM> engage with each other, and the winding body <NUM> is configured to provide the second winding part <NUM>, on one hand, the structural configuration of the bearing structure <NUM> is more reasonable and compact, and on the other hand, the structure of the bearing structure <NUM> is simpler and easy to be processed and realized, thereby decreasing the processing difficulty of the bearing structure <NUM>.

In some embodiments, the cover <NUM> is configured to protect the bearing structure <NUM> and the wire set <NUM> and to prevent impurities such as dust from entering the mounting recess <NUM> and thus influencing the normal operation of the strain sensor. In addition, the above configuration makes the appearance of the strain sensor more beautiful and neater, thereby improving the visual experience of the user.

In some embodiments, the winding body <NUM> has a cross-section in shape of a polygon. There are a plurality of second winding parts <NUM> disposed correspondingly to a plurality of sides of the polygon in a one-to-one manner. In this way, the second winding parts <NUM> each are disposed on the sides corresponding thereto, so that the processing of the second winding parts <NUM> is easier and simpler, and the structure of the bearing structure <NUM> is simpler and easy to be processed and realized, thereby decreasing the processing difficulty of the bearing structure <NUM>.

In this embodiment, the winding body <NUM> is in a structure of an octagonal prism. The number of the second winding parts <NUM> is eight. Eight second winding parts <NUM> are disposed correspondingly to eight sides of the octagonal prism in a one-to-one manner. Eight second winding parts <NUM> are disposed correspondingly to eight wire sets <NUM> in a one-to-one manner, so that the distribution of the wire sets <NUM> are more reasonable and compact, thereby decreasing the processing difficulty for the operator.

It should be noted that the number of sides of the bottom surface of the winding body <NUM> is not limited herein and may be adjusted according to operating conditions. In some embodiments, the winding body <NUM> is a quadrangular prism, a hexagonal prism, a decagonal prism, or a dodecagonal prism.

In some embodiments, a surface of the bearing structure <NUM> facing the cover <NUM> is higher than a surface of the base <NUM> facing the cover <NUM>. Alternatively, the surface of the bearing structure <NUM> facing the cover <NUM> is flush with the surface of the base <NUM> facing the cover <NUM>. In this way, in the detection process using the strain sensor, the above configuration ensures that the load applied onto the cover <NUM> can be directly applied onto the bearing structure <NUM> and then onto the wire set <NUM> through the bearing structure <NUM>, so as to change the resistance of the wire set <NUM> to accomplish the detection action of the strain sensor.

In this embodiment, the surface of the bearing structure <NUM> facing the cover <NUM> is higher than the surface of the base <NUM> facing the cover <NUM>. The cover <NUM> is connected to the bearing structure through a first fastener and to the base <NUM> through a second fastener. In some embodiments, the first fastener and the second fastener are screws or bolts, so that the attachment and the detachment between the cover <NUM> and the bearing structure <NUM> and between the cover <NUM> and the base <NUM> are easier and simpler, decreasing the difficulty of the attachment and the detachment.

In other embodiments which are not shown in the drawings, the surface of the bearing structure facing the cover is lower than the surface of the base facing the cover, so that the strain sensor can be used as a six-dimensional acceleration sensor.

As shown in <FIG>, the mounting structure <NUM> has a plate structure. The plate structure incudes a first surface <NUM> and a second surface <NUM> opposite to the first surface <NUM>. The first winding part <NUM> is disposed on the first surface <NUM>. The second surface <NUM> is an arch-shaped surface. The pre-defined gap <NUM> is formed between the second surface <NUM> and the inner surface of the mounting recess <NUM>. In this way, the above configuration not only makes the structure of the mounting structure <NUM> simpler and easy to be processed and realized, thereby decreasing the processing cost and the processing difficulty of the strain sensor, but also ensures that the pre-defined gap <NUM> can be formed between the mounting structure <NUM> and the inner surface of the mounting recess <NUM>, and thus ensures the resistance of the wire set <NUM> is able to be changed, thereby increasing the operational reliability of the strain sensor.

In some embodiments, the mounting structure <NUM> is connected to the base <NUM> by a snap-fit or a fastener.

As shown in <FIG> and <FIG>, the wire set <NUM> includes a first wire sub-set <NUM> and a second wire sub-set <NUM>. The first wire sub-set <NUM> includes at least two first wire parts arranged in a first pre-defined direction and spaced from each other. The second wire sub-set <NUM> includes at least two second wire parts arranged in a second pre-defined direction and spaced from each other. The first pre-defined direction and the second pre-defined direction are defined at an angle therebetween. In this embodiment, the first wire sub-set <NUM> includes two first wire parts arranged in the first pre-defined direction and spaced from each other, and the second wire sub-set <NUM> includes two second wire parts arranged in the second pre-defined direction and spaced from each other. In this way, the above configuration further increases the response speed of the strain sensor, prevents the phenomena such as creep and hysteresis of the strain sensor which may affect the detection sensitivity of the strain sensor, and also increases the detection precision of the strain sensor.

In some embodiments, the first wire sub-set <NUM> is wound by two wires winding into the first wire parts, respectively, and the two first wire parts are arranged in the first pre-defined direction and spaced from each other. The second wire sub-set <NUM> is wound by two wires winding into the second wire parts, respectively, and the two second wire parts are arranged in the second pre-defined direction and spaced from each other.

In some embodiments, there are a plurality of first wire sub-sets <NUM> and a plurality of second wire sub-sets <NUM>. The first wire sub-sets <NUM> are arranged along an inner circumferential surface of the mounting recess <NUM> and spaced from each other. At least one second wire sub-set <NUM> is disposed between two adjacent first wire sub-sets <NUM>. In this way, the above configuration further increases the detection sensitivity of the strain sensor and also increases the detection precision of the strain sensor.

In this embodiment, there are four first wire sub-sets <NUM> and four second wire sub-sets <NUM>. The four first wire sub-sets <NUM> are arranged along the inner circumferential surface of the mounting recess <NUM> and spaced from each other. One second wire sub-set <NUM> is disposed between two adjacent first wire sub-sets <NUM>. In this way, the above configuration makes the structural layout of the first wire sub-sets <NUM> and the second wire sub-sets <NUM> more reasonable and also increases the response speed of the strain sensor.

In some embodiments, a ratio of the measuring range of the strain sensor to a length of the wire of the first wire part is less than or equal to <NUM>. In this way, the above value range can ensure the feasibility of the strain sensor and thus increases the operational reliability of the strain sensor.

In some embodiments, a ratio of the measuring range of the strain sensor to a length of the wire of the second wire part is less than or equal to <NUM>. In this way, the above value range can ensure the feasibility of the strain sensor and thus increases the operational reliability of the strain sensor.

As shown in <FIG> and <FIG>, the strain sensor further includes a plurality of fixing structures <NUM>. The plurality of fixing structures <NUM> are disposed on the mounting structure <NUM>. Ends of wires of the wire set <NUM> wind on the fixing structures <NUM>, so that the ends of the wires are fixed by the fixing structures <NUM>. In this way, the fixing structures <NUM> enable the wire set <NUM> to be tensioned and fixed, increase the system rigidity of the strain sensor, and can be indirectly used as a frequency modulating means, so that the strain sensor can be applicable to different operating conditions.

In some embodiments, the fixing structures <NUM> are preloaded bolts.

In some embodiments, after the wires of the wire sets <NUM> pass through the first winding parts <NUM> and the second winding parts <NUM>, the ends of the wires are tensioned by the preloaded screws, so that the preloaded screws play a role in bracing the bearing structure <NUM> to suspend the bearing structure <NUM> at the central portion of the base <NUM>.

As shown in <FIG>, the first wire sub-set <NUM> is formed by two first wire parts, the second wire sub-set <NUM> is formed by two second wire parts, and they are numbered anticlockwise for ease of description. The number in parentheses denotes the wire part behind in the viewing direction. The directions of X+ and Y+ are set as <FIG>. The direction of Z+ is outwardly perpendicular to the paper.

As shown in <FIG>, the third wire <NUM>, the fourth wire <NUM>, the fifteenth wire <NUM>, the sixteenth wire <NUM>, the eighth wire <NUM>, the seventh wire <NUM>, the twelfth wire <NUM>, and the eleventh wire <NUM> are arranged as illustrated and constitute a parallel circuit, and a Wheatstone bridge is formed between each two of them. The first wire <NUM>, the second wire <NUM>, the ninth wire <NUM>, and the tenth wire <NUM> constitute a first Wheatstone bridge, the fifth wire <NUM>, the thirteenth wire <NUM>, the fourteenth wire <NUM>, and the sixth wire <NUM> constitute a second Wheatstone bridge, and then the first Wheatstone bridge is in series with the second Wheatstone bridge. In this series branch, there is a characteristic of U<NUM> being zero when U<NUM> changes. That is, the total resistance of one bridge circuit is unchanged when the other bridge circuit changes. The voltages U<NUM> and U<NUM> are measured to reflect the directions and the magnitudes of FX, FY, and MZ applied. The voltages U<NUM>, U<NUM>, and U<NUM> are measured to reflect the directions and the magnitudes of MX, MY, and FZ applied. The specific relationship is referred to the following equation: <MAT>.

The embodiments of the present invention further provide a robot (not shown) including the above-described strain sensor.

It can be known from the above description that the embodiments of the present invention have the following technical effects.

The bearing structure is directly connected to the wire set. In the detection process using the strain sensor, the load is directly applied onto the wire set through the bearing structure to take maximum advantage of the resistance strain effect of the wire set, which makes the response of the strain sensor more sensitive, eliminates the affection of the creep and the hysteresis of an elastomer on the detection sensitivity of the strain sensor, and thus solves the problem that the strain sensor in the related art has phenomena such as creep, hysteresis, and shift which affect the detection sensitivity thereof, thereby increasing the detection sensitivity and the response speed of the strain sensor and also increasing the detection precision of the strain sensor.

Apparently, the embodiments described above are merely some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art shall be included in the protection scope of the present invention as defined by the claims.

It is to be noted that terms, as used herein, are merely for describing the specific implementations, and not intended to limit the exemplary implementations of the present application. Unless otherwise specifically stated, the singular as used herein is intended to include the plural. Furthermore, it should be understood that terms "including" and/or "comprising", as used herein, indicate the presence of features, steps, tasks, devices, components, and/or combinations thereof.

It is to be noted that terms such as "first" and "second", as used in the description, claims and drawings of the present application, are used to distinguish similar objects, and are not necessarily used to define a particular order or sequence. It should be understood that data, as used in such a way, may be used interchangeably if appropriate, so that the implementations of the present application described here may be implemented in an order other than those illustrated or described here.

Claim 1:
A strain sensor, comprising:
a base (<NUM>) provided with a mounting recess (<NUM>);
a mounting structure (<NUM>) disposed on the base (<NUM>) and located in the mounting recess (<NUM>), a pre-defined gap (<NUM>) being formed between the mounting structure (<NUM>) and an inner surface of the mounting recess (<NUM>); and
a bearing structure (<NUM>) mounted in the mounting recess (<NUM>) and located outside the pre-defined gap (<NUM>), characterized in that the strain sensor further comprises:
a wire set (<NUM>) of a plurality of electrically conductive wires, at a side of the wire set (<NUM>) each of the wires being fixedly disposed on the bearing structure (<NUM>), and at another side of the wire set (<NUM>) each of the wires being fixedly disposed on the mounting structure (<NUM>) to detect the strain based on change of resistance of the wire set by a load applied through the bearing structure on the wire set.