Multi-dimensional force sensing system based on local high relative stiffness ratio structure

Abstract

This invention relates to a multidimensional force sensing system based on locally high relative stiffness ratio structures, belonging to the field of multidimensional force measurement technology. The invention addresses the problem of excessive structural weight of the load frame and support frame in large-scale multidimensional force sensing systems when achieving high-precision measurements. One system described in this invention comprises several locally high relative stiffness ratio structures. Each locally high relative stiffness ratio structure includes a load frame, a support frame, and several individual multidimensional force sensors. Each individual multidimensional force sensor has two thin load necks and is arranged side-by-side between the load frame and the support frame. All load frames and / or support frames of the locally high relative stiffness ratio structures are connected in parallel via lightweight frames. The high relative stiffness ratio refers to maximizing the relative stiffness ratio (rsr).

Description

Technical Field

[0001] This invention belongs to the field of multidimensional force measurement technology, specifically relating to a lightweight, large-size, high-precision multidimensional force sensing system. Background Technology

[0002] Multidimensional force sensors can detect information about forces acting in space. They play a crucial role in numerous fields, including aerospace robotic arms, aerospace docking, collaborative robots, biomimetic machinery, medical assistive devices, walking robots, wind tunnel force measurement, aerospace engine thrust testing, propeller thrust testing, automotive crash testing, minimally invasive surgical robots, grinding and polishing instruments, friction stir welding, and machine tool processing force measurement. The accuracy of the multidimensional forces they acquire directly affects the system's performance and control precision.

[0003] In wind tunnel testing and jet engine testing stations, large-size multidimensional force sensors (sensing systems) are crucial components. Inventions with application numbers 201910882361.6 and 201910883333.6 propose redundant parallel rod-type multidimensional force sensors and their calculation methods, enabling high-precision multidimensional force measurement. Invention with application number 201911341094.8 proposes a distributed multidimensional force measurement system and method. Invention with application number 202210563928.5 addresses the accuracy space problem of redundant parallel rod-type multidimensional force sensors and proposes a technical solution using virtual levers to improve the accuracy of optimal accuracy space measurement. Meanwhile, invention 202210576017.6 proposes a technical solution using a dual measurement system to achieve high-precision torque measurement during remote force measurement.

[0004] For redundant parallel rod distributed multidimensional force sensors, to improve measurement accuracy, the stress change at the load neck needs to be sufficiently small when the external load force changes. To achieve this, a high relative stiffness ratio structure is required, meaning that at the load neck of a single MAFS, the ratio of the relative stiffness along its main axis (the relative stiffness of the individual MAFS to the overall structure) to the relative stiffness in all other directions (the five directions other than the main axis) must be very large. A key condition for this high relative stiffness ratio structure is that the loading frame and supporting frame need to have very high anisotropic stiffness, which means that a solid metal block with approximately the same length, width, and height dimensions is required. This is not difficult for small-sized multi-dimensional force sensing systems. However, for large-sized multi-dimensional force sensors used in wind tunnel testing and jet engine testing stations, the length of each dimension of the force-bearing part (load frame) typically exceeds several meters. To achieve this, the dimensions of other dimensions must also be equally large, and the overall structure needs to be essentially a solid body, resulting in excessive structural weight. This is difficult to meet in practical engineering, and even if it could, it would require very high manufacturing costs, and manufacturing, transportation, and installation would be extremely difficult. The purpose of this invention is to solve the problem of excessive structural weight of the load frame and support frame when achieving high-precision measurement in large-sized multi-dimensional force sensing systems. Summary of the Invention

[0005] This invention addresses the problem of excessive structural weight of the load frame and support frame when achieving high-precision measurement in large-size multidimensional force sensing systems.

[0006] A multidimensional force sensing system based on locally high relative stiffness ratio structures is described. The system comprises several locally high relative stiffness ratio structures. Each locally high relative stiffness ratio structure includes a load frame, a support frame, and several individual multidimensional force sensors. Each individual multidimensional force sensor is a multidimensional force sensor with two thin load necks. The individual multidimensional force sensors are arranged side by side between the load frame and the support frame. The load frames and / or support frames of all locally high relative stiffness ratio structures are connected in parallel through lightweight frames.

[0007] The high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows:

[0008] The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ;

[0009] The relative stiffness along the principal axis is ;

[0010] The relative stiffness about the principal axis and along / about other axes is ;

[0011] The relative stiffness ratio at the load neck is .

[0012] Furthermore, the multidimensional force sensing system based on a locally high relative stiffness ratio structure also includes a reference frame, which is mechanically isolated from the load frame and the support frame. Multiple displacement sensors are arranged on the reference frame for the spatial pose of a single multidimensional force sensor.

[0013] Furthermore, in each locally high relative stiffness ratio structure, the axes of all individual multidimensional force sensors cannot be parallel and cannot all converge at a single point.

[0014] Furthermore, the load neck of a standalone multidimensional force sensor is either a flexible hinge or a mechanical hinge.

[0015] Furthermore, the stress curves at the load necks of all individual multi-dimensional force sensors in each locally high relative stiffness ratio structure must be close to a U-shape.

[0016] A multi-dimensional force sensing system based on a locally high relative stiffness ratio structure includes at least one lightweight load frame, at least one lightweight support frame, and several individual multi-dimensional force sensors. The lightweight load frame and lightweight support frame are load frames and support frames with lightweight structures.

[0017] When using one lightweight load frame and / or one lightweight support frame, i.e., the lightweight load frame is a whole, and / or the lightweight support frame is a whole; when there are at least two lightweight load frames, and / or at least two lightweight support frames, the at least two lightweight load frames are connected in parallel through the lightweight frame, and / or the at least two lightweight support frames are connected in parallel through the lightweight frame.

[0018] The individual multi-dimensional force sensor is a multi-dimensional force sensor with two thin load necks, and the individual multi-dimensional force sensors are arranged side by side between the lightweight load frame and the lightweight support frame;

[0019] Each individual multidimensional force sensor, together with several other individual multidimensional force sensors in its vicinity, constitutes a locally high relative stiffness ratio structure, where high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows:

[0020] The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ;

[0021] The relative stiffness along the principal axis is ;

[0022] The relative stiffness about the principal axis and along / about other axes is ;

[0023] The relative stiffness ratio at the load neck is .

[0024] Furthermore, the multidimensional force sensing system based on a locally high relative stiffness ratio structure also includes a reference frame, which is mechanically isolated from the lightweight load frame and the lightweight support frame. Multiple displacement sensors are arranged on the reference frame for the spatial pose of a single multidimensional force sensor.

[0025] Furthermore, in a structure with a high local relative stiffness ratio, the axes of all individual multidimensional force sensors cannot be parallel and cannot all converge at a single point.

[0026] Furthermore, the load neck of a standalone multidimensional force sensor is either a flexible hinge or a mechanical hinge.

[0027] Furthermore, the stress curves at the load necks of all individual multidimensional force sensors in a locally high relative stiffness ratio structure must be close to a U-shape.

[0028] The present invention has the following beneficial effects:

[0029] While maintaining the accuracy of multidimensional force measurement, a single load and support frame is divided into several local load and support frames, thereby significantly reducing the overall weight of the multidimensional force measurement system. This structure allows for a substantial reduction in the structural weight of large-size multidimensional force sensing systems while preserving measurement accuracy. Attached Figure Description

[0030] Figure 1(a) and Figure 1(b) are schematic diagrams of the structure of a large-size multidimensional force sensing system.

[0031] Figure 2(a) shows the stress curve at the load neck of a single multi-dimensional force sensor under relatively flexible load frame conditions; Figures 2(b) to 2(e) are enlarged views of the stress curve in Figure 2(a).

[0032] Figure 3 The stress curves at the load necks of the load frame and the support frame, which have very high stiffness.

[0033] Figure 4 This is a schematic diagram of three MAFS fully constrained structures.

[0034] Figure 5 This is a schematic diagram of four MAFS fully constrained structures.

[0035] Figure 6(a) shows the relative stiffness ratio curve at the load neck and a simplified schematic diagram of the load neck as a slider; Figures 6(b) to 6(e) are enlarged views of the relative stiffness ratio curve in Figure 6(a).

[0036] Figure 7(a) is a stress distribution curve with load offset at the load neck; Figures 7(b) to 7(m) are enlarged views of the stress distribution curve at the load neck in Figure 7(a).

[0037] Figure 8 This is a stress curve diagram showing the load offset and the stress at the load neck.

[0038] Figure 9 This is a stress curve showing how the load distance ld varies.

[0039] Figure 10(a) is a schematic diagram of 12 or more individual multidimensional force sensors set between the load frame and the support frame; Figures 10(b) to 10(m) are stress curves at the load neck of the 12 individual multidimensional force sensors in Figure 10(a).

[0040] Figure 11 This is a schematic diagram of a multidimensional force sensing system for a structure with a local high relative stiffness ratio (flexible hinge).

[0041] Figure 12 This is a schematic diagram of a multidimensional force sensing system for a structure with a high relative stiffness ratio in a localized area (mechanical hinge). Detailed Implementation Specific implementation method one:

[0043] One of the most important characteristics of a high relative stiffness ratio structure is that the load frame and the support frame need to be solid structures with basically equal length, width and height. For large-sized load-bearing structures, usually only the load-bearing area is large along one or two dimensions. However, in order to achieve high measurement accuracy, the load frame and the support frame must be very large in all three dimensions and be basically solid structures, which leads to excessive system weight.

[0044] This embodiment is a multidimensional force sensing system based on locally high relative stiffness ratio structures. The system includes several locally high relative stiffness ratio structures. Each locally high relative stiffness ratio structure includes a load frame, a support frame, and several individual multidimensional force sensors. Each individual multidimensional force sensor is a multidimensional force sensor with two thin load necks. The individual multidimensional force sensors are arranged side by side between the load frame and the support frame. The load frames and / or support frames of all locally high relative stiffness ratio structures are connected in parallel through lightweight frames.

[0045] The high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows:

[0046] The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ;

[0047] The relative stiffness along the principal axis is ;

[0048] The relative stiffness about the principal axis and along / about other axes is ;

[0049] The relative stiffness ratio at the load neck is .

[0050] Lightweight refers to not using a solid, monolithic structure or removing the constraint that dimensions in all dimensions need to be basically consistent. In other words, a lightweight frame is a frame that does not use a solid, monolithic structure, or it removes the constraint that dimensions in the three dimensions need to be basically consistent. That is, the structural dimensions of a lightweight frame do not need to be large in all three dimensions (especially in the thickness direction).

[0051] The load neck of a standalone multidimensional force sensor can be a flexible hinge or a mechanical hinge. When a mechanical hinge is used, the lower the friction, the better.

[0052] The multidimensional force sensing system based on a locally high relative stiffness ratio structure may also include a reference frame, which is mechanically isolated from the load frame and the support frame. Multiple displacement sensors are arranged on the reference frame for measuring the spatial pose of individual multidimensional force sensors. Finally, the spatial multidimensional forces measured by multiple individual multidimensional force sensors are combined and calculated to obtain the multidimensional force of the entire sensing system.

[0053] When the external load distribution range is large, the existing multidimensional force sensing system also needs to have a large structural size. As shown in Figure 1(a) and Figure 1(b), multiple individual multidimensional force sensors 3 are connected in parallel through a loading frame 1 and a supporting frame 2 to form a distributed multidimensional force sensing system. In order to achieve high-precision measurement, the stiffness of the loading frame and the supporting frame in all directions (i.e., the stiffness along / about the three axes x, y, and z) must be as large as possible. Therefore, their structural size needs to be relatively large in all three dimensions, and they are basically a solid body (Figure 1(a) is a planar structure, that is, the two dimensions are basically the same, and Figure 1(b) is a three-dimensional structure, which requires the three dimensions to be basically the same). For example, in Figure 1(a), since the horizontal distribution range of the external force is close to 10m, the transverse dimension of the structure obviously needs to reach 10m. However, to ensure measurement accuracy, its longitudinal dimension also needs to reach about 10m. For the three-dimensional structure in Figure 1(b), when the planar dimension of the upper stress area is 10m*10m, the dimensions along all three dimensions need to be close to 10m, and both the load frame and the support frame need to be solid. Therefore, it can be seen that the weight of the system structure will be very large.

[0054] Through related research, it was found that in order to achieve high-precision multidimensional force measurement, the stress curve change at the load neck of a single multidimensional force sensor needs to be relatively small. The load neck is the thinner structure (flexible hinge) at both ends of 3 in the figure.

[0055] As shown in Figures 2(a) to 2(c), if the dimensions of the load frame are relatively small along certain dimensions, or if it is a thin-walled structure, the load frame will undergo relatively large deformation when the external load is concentrated in certain local areas. At this time, the load neck will undergo relatively large bending (or torsion) deformation. Therefore, the shape of the stress curve at the load neck will change significantly under various external load conditions, and the measurement accuracy of multidimensional forces will be greatly affected.

[0056] for Figure 3For such load-bearing and support frames with very high stiffness, regardless of the changes in the external load applied to the load-bearing frame, the stress curve at the load neck of the planar structure is a relatively perfect U-shaped (or inverted U-shaped) curve, such as... Figure 3 The curve shown in the lower left corner; for three-dimensional structures, the stress surface at the load neck is a relatively perfect U-shaped surface (or an inverted U-shaped surface), such as... Figure 3 The curve shown in the lower right corner. Because the stress curve at the load neck changes little under various external load conditions, the measurement accuracy of multidimensional forces is relatively high. Figure 3 The arrangement of multiple individual multidimensional force sensors in the structure is a fully constrained structure.

[0057] A fully constrained structure refers to a structure that remains stable when the load neck is considered as an ideal mechanical hinge, and the load frame is subjected to any force. Figure 4 and Figure 5 The schematic diagram of the fully constrained structure shows a planar structure. This system requires at least three individual multi-force sensors. Each rod in the fully constrained structure represents one multi-force sensor (MAFS). Figure 4 There are 3. Figure 5 There are four members in the middle. When the load-bearing frame is subjected to any force, the structure must remain stable, meaning that the three or four members and their extended axes cannot converge at a single point, nor can they all be parallel. For example... Figure 5 In a three-planar structure, the axes of all individual multi-dimensional force sensors in the system cannot be parallel, nor can they all converge at a single point. For a three-dimensional spatial system, at least six multi-dimensional force sensors are required, and the axes of all individual multi-dimensional force sensors cannot be parallel, cannot all lie in the same plane, and cannot all converge at a single point; that is, the structure must remain stable when the load frame is subjected to any force. Clearly... Figure 5 The structure shown on the lower left is a fully constrained structure, while the structures shown in the middle and right are not fully constrained structures.

[0058] The full-constraint structure can also be described by the relative stiffness ratio at the load neck. As shown in Figure 6(a), any single multi-dimensional force sensor in the system is cut off and removed from the load neck. Next, we examine the stiffness of the overall structure at the load neck. Note that although the figure is a planar diagram, it represents a three-dimensional structure, that is, the hinge has six degrees of freedom along / around three coordinate axes. It is the stiffness of a single MAFS along its main axis. It is the stiffness of the overall structure along the principal axis.

[0059] The relative stiffness of the two along the principal axis is: ;

[0060] The relative stiffness of the two about the principal axis and along / about other axes is: ;

[0061] Then, the relative stiffness ratio at the load neck is ;

[0062] If we want the stress curve at the load neck to remain relatively stable under any stress conditions, then the relative stiffness at the load neck needs to be relatively large. Therefore, we need to maximize the relative stiffness ratio. This means that multiple multi-dimensional force sensors need to be implemented in a fully constrained structure, and the load frame and support frame have very high stiffness.

[0063] The load neck stiffness curve will be further explained below to illustrate its specific meaning and its impact on the accuracy of multidimensional force measurement.

[0064] As shown in Figure 7(a), the left side of Figure 7(a) shows a single multidimensional force sensor in a distributed multidimensional force sensing system. The stress distribution at its loading neck directly determines the measurement accuracy of the multidimensional force sensor. The right side of Figure 7(a) shows the load neck stress distribution curves corresponding to different load offsets. In this invention, the load neck stress curve specifically refers to the stress curve along the principal axis. Figures 7(b) to 7(f) are enlarged views of the curves in Figure 7(a). In fact, Figure 7(a) is mainly to show the shape of the load neck stress distribution curve. The coordinate values ​​and other details can be omitted here without affecting the content and understanding of this invention. That is, Figures 7(b) to 7(f) are only for illustrative purposes and can be omitted without affecting the understanding of this invention. As shown in Figures 7(a) to 7(f), when subjected to a vertically upward tensile force, the distance between this force and the centerline of the load neck is called the loading offset (lo). The stress at the load neck when lo=0 is considered the reference stress. As lo increases, the stress curve changes more and more compared to the reference stress. This stress curve refers to the stress along the main axis at the load neck kk.

[0065] The change in stress shape is defined by the correlation coefficient between stress curves:

[0066]

[0067] In the formula, s r This is the reference stress curve, s i For any other stress curve, the reference stress curve is the stress along the principal axis of the load neck when the load offset is 0, and the other arbitrary stress curves refer to the stress along the principal axis of the load neck when the load offset is not 0.

[0068] like Figure 8As shown, as the load offset gradually increases, the correlation coefficient between the stress curve at the load neck and the reference stress curve gradually decreases.

[0069] like Figure 9 As shown (actually) Figure 9 The main purpose is to demonstrate the impact of load distance on correlation, i.e., the shape of the curve in the figure. It is not necessary to show its coordinate values ​​and other details, and this will not affect the content and understanding of the present invention. Therefore, no enlarged view of the curve is provided to show the coordinate values ​​and other details, and this will not affect the understanding of the present invention. Figure 9 The top left indicates that a force F is applied to a point. The loading distance (ld) from the load neck also has a certain influence on the stress correlation at the load neck. The loading distance refers to the distance from the load application location to the load neck along the principal axis. From Figure 9 As can be seen from the data, when the load distance ld is greater than the load neck diameter, the stress curves tend to be uniform. The stress curve at the load neck when ld approaches infinity can be set as the reference curve. In practice, the curve at ld=40mm is used as the reference curve. The correlation coefficient is calculated and it can be seen that when ld is greater than the load neck diameter, the correlation coefficient approaches 1. Since the load force is always applied far away from the load neck in actual work, it can be seen that the influence of the load distance on the correlation can be ignored.

[0070] The similarity in the shape of the load neck stress curves means that the absolute value of the correlation coefficient between the two load neck stress curves is close to 1. That is, when both are tensile or compressive stresses, the value is close to 1, and when one is tensile stress and the other is compressive stress, the value is close to -1.

[0071] As shown in Figure 10(a), assuming there are more than 12 individual multidimensional force sensors between the load frame and the support frame, Figures 10(b) to 10(m) show the stress curves at the load necks of the 12 individual multidimensional force sensors in Figure 10(a). When a local full constraint ratio structure is adopted, the stress curves at load necks 2, 3, and 5-12 are relatively ideal. Although the stress curves at load necks 1 and 4 are not ideal, this is mainly because the stress on load necks 1-4 is very small, and load necks 1-4 are basically unloaded under this external force condition, thus having almost no impact on the measurement results. As can be seen from the figures, compared with Figure 2, the stress curves of load necks 5-12 in Figure 10(a) under the stress state are close to a positive U-shape or an inverted positive U-shape, indicating that the stress curves are good. Although the stress curves of load necks 1 and 4 are not good in shape, the stress on load necks 1-4 is very small, and the impact on the calculation of multidimensional forces is very small.

[0072] Example 1

[0073] like Figure 11As shown, the system includes several locally high relative stiffness ratio structures. Each locally high relative stiffness ratio structure includes a loading frame 1, a supporting frame 2, and several individual multidimensional force sensors 3. The multiple individual multidimensional force sensors 3 are connected in parallel through the loading frame 1 and the supporting frame 2. The loading frames and / or supporting frames of all locally high relative stiffness ratio structures are connected in parallel through lightweight frames. The load neck of each multidimensional force sensor is a flexible hinge. For large-size multidimensional force sensing systems, multiple locally fully constrained high relative stiffness ratio structures are used. Compared with Figure 1, the weight of the loading frame and supporting frame is significantly reduced. For all load necks, the stress curve shape can still be relatively consistent under any external load, that is, a better U-shape or inverted U-shape (planar structure), or a U-shaped curved surface or inverted U-shaped curved surface (three-dimensional structure). Figure 11 The reference frame 4 in the text refers to the frame that is isolated from other load-bearing structures on the ground. That is, the frame that does not change shape when the load frame is subjected to force. It is used as the basic reference object when multiple MAFS are combined for force calculation, that is, as a reference coordinate system. Specific Implementation Method Two:

[0075] This embodiment is a multi-dimensional force sensing system based on a locally high relative stiffness ratio structure. Based on the first specific embodiment, this embodiment can further improve the load frame and support frame into lightweight structures, namely lightweight load frame and lightweight support frame.

[0076] Lightweighting refers to not using a solid, integral structure or removing the restriction that dimensions in all dimensions must be essentially consistent. In this embodiment, the lightweight load-bearing frame and lightweight support frame are frame structures that do not use a solid, integral structure, but are required to have high rigidity.

[0077] Of course, the lightweight load frame, the lightweight support frame (which is an improved lightweight structure), and the lightweight frames connected in parallel can be the same or different. When they are the same, the lightweight load frame and the lightweight support frame can constitute a whole lightweight frame.

[0078] Therefore, in this embodiment, the system includes at least one lightweight load frame, at least one lightweight support frame, and several individual multidimensional force sensors. The lightweight load frame and the lightweight support frame are load frames and support frames with lightweight structures.

[0079] When one lightweight load frame and / or one lightweight support frame are used, the lightweight load frame and / or lightweight support frame are a whole; when there are at least two lightweight load frames and / or lightweight support frames, the at least two lightweight load frames are connected in parallel through the lightweight frame, and / or, the at least two lightweight support frames are connected in parallel through the lightweight frame.

[0080] The individual multi-dimensional force sensor is a multi-dimensional force sensor with two thin load necks, and the individual multi-dimensional force sensors are arranged side by side between the lightweight load frame and the lightweight support frame;

[0081] Each individual multidimensional force sensor, together with several other individual multidimensional force sensors in its vicinity, constitutes a locally high relative stiffness ratio structure, where high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows:

[0082] The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ;

[0083] The relative stiffness along the principal axis is ;

[0084] The relative stiffness about the principal axis and along / about other axes is ;

[0085] The relative stiffness ratio at the load neck is .

[0086] Example 2

[0087] like Figure 12 As shown, the system includes a lightweight load frame 1, a lightweight support frame 2, and several individual multi-dimensional force sensors 3. To maximize the relative stiffness ratio at the load neck, a mechanical hinge structure can be used. If this mechanical hinge is considered an ideal hinge, i.e., there is no mechanical backlash or friction at the hinge, then obviously, apart from having a large stiffness along the principal axis, the stiffness around the principal axis and along / around other axes is 0. Therefore, the relative stiffness ratio tends to infinity. This is an ideal structure, very useful for lightweight, large-size, multi-dimensional force sensing systems. However, because mechanical hinges inevitably have mechanical backlash and friction, their accuracy is generally lower than that of structures using flexible hinges. Meanwhile... Figure 12 The structure shown is a lightweight load frame that exists as a whole in the form of a lightweight framework, and a lightweight support frame that exists as a whole in the form of a lightweight framework. Figure 12 Reference frame 4 is isolated from other load-bearing structures and is used as a basic reference when multiple MAFS perform force merging calculations, i.e., as a reference coordinate system.

[0088] The above examples of the present invention are merely illustrative of the computational model and process of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A multidimensional force sensing system based on a locally high relative stiffness ratio structure, characterized in that, The system includes several locally high relative stiffness ratio structures. Each locally high relative stiffness ratio structure includes a load frame, a support frame, and several individual multidimensional force sensors. Each individual multidimensional force sensor is a multidimensional force sensor with two thin load necks. The individual multidimensional force sensors are arranged side by side between the load frame and the support frame. The load frames and / or support frames of all locally high relative stiffness ratio structures are connected in parallel through lightweight frames. The high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows: The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ; The relative stiffness along the principal axis is ; The relative stiffness about the principal axis and along / about other axes is ; The relative stiffness ratio at the load neck is .

2. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 1, characterized in that, The multidimensional force sensing system based on a locally high relative stiffness ratio structure also includes a reference frame, which is mechanically isolated from the load frame and the support frame. Multiple displacement sensors are arranged on the reference frame for the spatial pose of a single multidimensional force sensor.

3. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 1 or 2, characterized in that, In every locally high relative stiffness ratio structure, the axes of all individual multidimensional force sensors cannot be parallel and cannot all converge at a single point.

4. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 3, characterized in that, The load neck of a standalone multidimensional force sensor is either a flexible hinge or a mechanical hinge.

5. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 4, characterized in that, The stress curves at the load necks of all individual multi-dimensional force sensors in each locally high relative stiffness ratio structure must be close to a U-shape.

6. A multidimensional force sensing system based on a locally high relative stiffness ratio structure, characterized in that, The system includes at least one lightweight load frame, at least one lightweight support frame, and several individual multidimensional force sensors. The lightweight load frame and lightweight support frame are load frames and support frames with lightweight structures. When using one lightweight load frame and / or one lightweight support frame, i.e., the lightweight load frame is a whole, and / or the lightweight support frame is a whole; when there are at least two lightweight load frames, and / or at least two lightweight support frames, the at least two lightweight load frames are connected in parallel through the lightweight frame, and / or the at least two lightweight support frames are connected in parallel through the lightweight frame. The individual multi-dimensional force sensor is a multi-dimensional force sensor with two thin load necks, and the individual multi-dimensional force sensors are arranged side by side between the lightweight load frame and the lightweight support frame; Each individual multidimensional force sensor, together with several other individual multidimensional force sensors in its vicinity, constitutes a locally high relative stiffness ratio structure, where high relative stiffness ratio refers to maximizing the relative stiffness ratio. The relative stiffness is as follows: The stiffness of the entire structure along the principal axis before any single multi-dimensional force sensor is cut off and removed from the load neck is denoted as follows: And the stiffness about the principal axis and along / about other axes is denoted as The stiffness of a single multi-dimensional force sensor along its principal axis after being cut off and removed from the load neck is denoted as . And the stiffness about the principal axis and along / about other axes is denoted as ; The relative stiffness along the principal axis is ; The relative stiffness about the principal axis and along / about other axes is ; The relative stiffness ratio at the load neck is .

7. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 6, characterized in that, The multidimensional force sensing system based on a locally high relative stiffness ratio structure also includes a reference frame, which is mechanically isolated from the lightweight load frame and the lightweight support frame. Multiple displacement sensors are arranged on the reference frame for the spatial pose of a single multidimensional force sensor.

8. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 6 or 7, characterized in that, In a structure with a high local relative stiffness ratio, the axes of all individual multidimensional force sensors cannot be parallel and cannot all converge at a single point.

9. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 8, characterized in that, The load neck of a standalone multidimensional force sensor is either a flexible hinge or a mechanical hinge.

10. The multidimensional force sensing system based on a locally high relative stiffness ratio structure according to claim 9, characterized in that, In structures with high relative stiffness, the stress curves at the load necks of all individual multidimensional force sensors must be close to a U-shape.

Images