Simulation system
The simulation system adjusts muscle region parameters using measurement results from antagonistic muscle groups to improve simulation accuracy by matching subject-specific muscle strength ratios, addressing individual variations in muscle strength.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
AI Technical Summary
Existing musculoskeletal simulation systems fail to accurately account for individual variations in muscle strength, leading to inaccurate simulations of the musculoskeletal system.
A simulation system that adjusts muscle region parameters based on measurement results from antagonistic muscle groups, using a ratio-based adjustment process to match the subject's muscle strength ratios, thereby improving simulation accuracy.
Enhances the accuracy of musculoskeletal model simulations by customizing them to individual variations in muscle development.
Smart Images
Figure 2026092543000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a simulation system.
Background Art
[0002] In a simulation system for a musculoskeletal model including a plurality of muscle parts arranged along a skeleton, something like AnyBody (registered trademark) developed and popularized by the University of Aalborg, Denmark is known. In such a simulation system, simulation can be performed while changing the value of the muscle mass of each muscle constituting the musculoskeletal model.
[0003] Patent Document 1 discloses a configuration for adjusting muscle strength in units of muscle groups including a plurality of muscles. More specifically, it discloses an example of simulating how the values of a plurality of types (six types) of each muscle group included in a set of muscle groups (hip extensor group, hip flexor group, hip internal rotator group, hip external rotator group, hip adductor group, hip abductor group) change according to the setting of dressing conditions (conditions 0 to 6).
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In the simulation of the influence of exercise on muscles, even under the same dressing conditions, there are variations in muscle strength for each part of the body depending on the person. Therefore, if these cannot be taken into account, it is impossible to accurately perform a simulation of the musculoskeletal system suitable for that person. Even using machine learning, it is difficult to solve this problem.
[0006] The purpose of this disclosure is to provide a technology that efficiently improves the accuracy of musculoskeletal model simulations that take into account variations in muscle development among individuals. [Means for solving the problem]
[0007] A simulation system for a musculoskeletal model that includes multiple muscle regions arranged along the skeleton, Measurement result acquisition means for acquiring a first measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to a first anatomy train of a subject, and a second measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to a second anatomy train that are antagonistic to the first anatomy train of the subject. Based on the comparison results of the first measurement result and the second measurement result, an adjustment means performs an adjustment process in the musculoskeletal model to adjust the muscle region parameters of at least one of the plurality of muscle regions belonging to the first anatomy train and the plurality of muscle regions belonging to the second anatomy train. including, A simulation system is provided.
[0008] The adjustment means may perform the adjustment process based on the ratio of the first measurement result to the second measurement result.
[0009] The adjustment means may perform the adjustment process such that the ratio of the muscle region parameters of the plurality of muscle regions belonging to the first anatomy train and the muscle region parameters of the plurality of muscle regions belonging to the second anatomy train in the musculoskeletal model approaches the ratio of the first measurement result to the second measurement result of the subject.
[0010] The first anatomical train is the superficial front line (SFL), and the second anatomical train may be the superficial back line (SBL).
[0011] The first anatomical train is the front functional line (FFL), and the second anatomical train may be the back functional line (BFL). [Effects of the Invention]
[0012] According to this disclosure, it is possible to efficiently improve the accuracy of musculoskeletal model simulations that take into account variations in muscle development among individuals. [Brief explanation of the drawing]
[0013] [Figure 1] This is a block diagram of the simulation device. [Modes for carrying out the invention]
[0014] The present invention will be described below through embodiments of the invention, but the invention claimed is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means of solving the problem. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations have been omitted where necessary.
[0015] In the following embodiments, the description will be divided into multiple sections or embodiments where necessary for convenience. Unless otherwise specified, these are not unrelated, and one may be a modification, application, detailed explanation, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including number, numerical value, quantity, and range), unless otherwise specified or clearly limited to a specific number in principle, it is not limited to that specific number, and may be greater than or less than that number.
[0016] Furthermore, in the following embodiments, the components (including operation steps, etc.) are not necessarily essential unless specifically stated or considered to be fundamentally essential. Similarly, in the following embodiments, when referring to the shape or positional relationship of components, etc., it shall include those substantially similar to or resembling their shape, etc., unless specifically stated or considered to be fundamentally different. The same applies to the numbers, etc. (including number, numerical value, quantity, and range) mentioned above.
[0017] The simulation device 1 according to an embodiment of this disclosure will be described below with reference to Figure 1. Figure 1 is a block diagram of the simulation device 1. The simulation device 1 is a specific example of a simulation system that estimates the fatigue and energy consumption of each muscle region of a subject by inverse dynamics analysis using a musculoskeletal model. The musculoskeletal model includes a skeleton and multiple muscle regions arranged along the skeleton. The simulation device 1 estimates the fatigue and energy consumption of each muscle region of a subject with higher accuracy for each subject by tuning the muscle region parameters of multiple muscle regions. The simulation device 1 may be implemented as a single device or as distributed processing using multiple devices.
[0018] As shown in Figure 1, the simulation device 1 includes a processor 2, memory 3, communication interface 4, LCD 5 (Liquid Crystal Display), and input interface 6.
[0019] Processor 2 has access to memory 3. Processor 2 is configured to communicate with external devices via communication interface 4. Processor 2 reads and executes programs stored in memory 3. This allows processor 2 and other hardware to function as a musculoskeletal model selection unit 10, a measurement result acquisition unit 11, an adjustment unit 12, an inverse dynamics analysis unit 13, and an output unit 14. Memory 3 also stores a musculoskeletal model database 15.
[0020] The LCD 5 is a specific example of an output device. The input interface 6 is a specific example of an input device. The input interface 6 typically consists of a touch panel superimposed on the LCD 5.
[0021] The skeletal model database 15 includes a plurality of skeletal models 16. Each skeletal model 16 has initial values (reference values) of muscle part parameters for each of 600 or more muscle parts. The plurality of skeletal models 16 include, as an example, an AM50 model 16a, a GM model 16b, and a JAMA50 16c.
[0022] The AM50 model 16a is a skeletal model also called "50th Percentile American Male" and corresponds to the 50th percentile (median) of American males. In short, it can be said that the AM50 model 16a represents the average height, weight, body shape, and muscle mass of adult American males.
[0023] The GM model 16b is a skeletal model also called "Global Human Body Models Consortium, GHBMC" and is a globally standardized skeletal model. That is, the GM model 16b is based on data of various races and genders. In this embodiment, the GM model 16b is a skeletal model corresponding to the so-called 50th. However, it is not limited to this, and the GM model 16b may be a skeletal model corresponding to the so-called 5th or 95th.
[0024] The JAMA50 16c is a skeletal model also called "Japanese Anthropometric Model for the 50th Percentile Japanese Male" and is a skeletal model based on the 50th percentile of Japanese males. Therefore, the JAMA50 16c reflects the average body shape and muscle mass of Japanese people.
[0025] In this embodiment, "muscle site parameter" refers to a parameter relating to a muscle site, typically meaning muscle mass or muscle strength. In other words, muscle mass and muscle strength are specific examples of muscle site parameters. A proportional relationship is generally considered to exist between muscle mass and muscle strength. However, while muscle strength decreases with age, muscle mass does not decrease as much. In this embodiment, we will continue the explanation assuming that the muscle site parameter is muscle strength.
[0026] The musculoskeletal model selection unit 10 retrieves a musculoskeletal model 16 selected via the input interface 6 from among multiple musculoskeletal models 16 stored in the musculoskeletal model database 15. Typically, the musculoskeletal model 16 that most closely matches the subject's musculoskeletal system is selected.
[0027] The measurement result acquisition unit 11 acquires a first measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to the subject's first anatomy train, and a second measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to the subject's second anatomy train, which are antagonistic to the first anatomy train. The measurement result acquisition unit 11 is one specific example of a measurement result acquisition means.
[0028] The first and second anatomical trains are specific examples of anatomical trains. Here, an anatomical train refers to the parts of the body that are affected when a load is applied to one part. The following are examples of anatomical trains.
[0029] Superficial Front Line (hereinafter simply referred to as SFL): The SFL is a fascial line that runs along the front of the body, from the top of the head to the toes, and plays a role in maintaining posture and flexing the body forward. Muscles belonging to the SFL include the extensor digitorum brevis, extensor digitorum longus, tibialis anterior, extensor hallucis longus, extensor digitorum longus, rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, rectus abdominis, sternalis, and sternocleidomastoid.
[0030] Superficial Back Line (hereinafter simply referred to as SBL): The SBL is a fascial line that runs along the posterior surface from the toes to the crown of the head, and plays a role in maintaining posture and extending the body backward. Muscles belonging to the SBL include the flexor digitorum brevis, gastrocnemius, biceps femoris, semitendinosus, semimembranosus, iliocostalis, longissimus, and spinalis.
[0031] Front Functional Line (hereinafter simply referred to as FFL): The FFL is a fascial line that runs diagonally across the front of the body, connecting opposite shoulders and legs, and contributing to diagonal movement and rotation. Muscles belonging to the FFL include the pectoralis major, rectus abdominis, and adductor longus.
[0032] Back Functional Line (hereinafter simply referred to as BFL): The back fascia line (BFL) is a fascial line that runs diagonally along the back of the body, connecting opposite shoulders and legs, and contributing to diagonal movement and rotation. Muscles belonging to the BFL include the latissimus dorsi, gluteus maximus, and vastus lateralis.
[0033] SFL and SBL are antagonistic muscles to each other. Similarly, FFL and BFL are antagonistic muscles to each other. Therefore, if the first anatomical train is SFL, the second anatomical train will be SBL, and if the first anatomical train is FFL, the second anatomical train will be BFL.
[0034] For the sake of explanation, the measurement result acquisition unit 11 will be described as follows, assuming that the first anatomy train is SFL and the second anatomy train is SBL.
[0035] The first measurement result, which is the result of muscle strength measurement using multiple muscle groups belonging to the SFL, is typically the result of lower limb extension force measurement. Lower limb extension force is typically the joint torque at the knee joint during lower limb extension (hereinafter referred to as knee joint torque during extension). The second measurement result, which is the result of muscle strength measurement using multiple muscle groups belonging to the SBL, is typically the result of lower limb flexion force measurement. Lower limb flexion force is typically the joint torque at the knee joint during lower limb flexion (hereinafter referred to as knee joint torque during flexion).
[0036] The measurement result acquisition unit 11 typically acquires a first measurement result (knee joint torque during extension) and a second measurement result (knee joint torque during flexion) via the input interface 6.
[0037] The adjustment unit 12 performs an adjustment process to adjust the muscle strength of at least one of the multiple muscle groups belonging to the SFL and the multiple muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10, based on the comparison result of the knee joint torque during extension and the knee joint torque during flexion. Specifically, the adjustment unit 12 performs the above adjustment process based on the ratio of the knee joint torque during extension and the knee joint torque during flexion. More specifically, the adjustment unit 12 performs the above adjustment process so that the ratio of the muscle strength of the multiple muscle groups belonging to the SFL and the muscle strength of the multiple muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 approaches the ratio of the knee joint torque during extension and the knee joint torque during flexion of the subject. Specifically, it is as follows.
[0038] In other words, the ratio of knee joint torque during extension to knee joint torque during flexion is generally known to be 3:2. This ratio will also be referred to as the reference ratio below. Therefore, in each musculoskeletal model stored in the musculoskeletal model database 15, the ratio of the initial muscle strength values of multiple muscle groups belonging to the SFL to the initial muscle strength values of multiple muscle groups belonging to the SBL is set to 3:2.
[0039] In contrast, let's assume, for example, that the ratio in the subject was 3.2:2. In this case, the adjustment unit 12 adjusts at least one of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 so that the ratio of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 approaches 3.2:2. Specifically, the adjustment unit 12 adjusts at least one of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 so that the ratio of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 matches 3.2:2.
[0040] When the adjustment unit 12 adjusts only the muscle strength of multiple muscle groups belonging to the SFL in the musculoskeletal model during the above adjustment process, it typically multiplies the initial values of the muscle strengths of the multiple muscle groups belonging to the SFL in the musculoskeletal model by a uniform 3.2 / 3.0 = 1.0667. That is, the initial values of the muscle strengths of the extensor digitorum brevis, extensor digitorum longus, tibialis anterior, extensor hallucis longus, extensor digitorum longus, rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, rectus abdominis, sternalis, and sternocleidomastoid muscles in the musculoskeletal model are uniformly multiplied by a uniform 3.2 / 3.0 = 1.0667. As a result, the ratio of the muscle strengths of multiple muscle groups belonging to the SFL to the muscle strengths of multiple muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 becomes 3.2:2, which roughly matches the measured ratio specific to the subject.
[0041] Similarly, when the adjustment unit 12 adjusts only the muscle strength of multiple muscle groups belonging to the SBL in the musculoskeletal model during the adjustment process described above, it typically multiplies the initial values of the muscle strengths of the multiple muscle groups belonging to the SBL in the musculoskeletal model by a uniform 3.0 / 3.2 = 0.9375. That is, it multiplies the initial values of the muscle strengths of the flexor digitorum brevis, gastrocnemius, biceps femoris, semitendinosus, semimembranosus, iliocostalis, longissimus, and spinalis muscles in the musculoskeletal model by a uniform 3.0 / 3.2 = 0.9375. As a result, the ratio of the muscle strengths of multiple muscle groups belonging to the SFL and the muscle strengths of multiple muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model selection unit 10 becomes 3.2:2, which roughly matches the subject-specific ratio.
[0042] The inverse dynamics analysis unit 13 calculates the joint torque generated at each joint of a musculoskeletal model using inverse dynamics analysis by having the musculoskeletal model, whose muscle strength in each muscle group has been adjusted by the adjustment unit 12, perform a predetermined movement. The predetermined movement is, for example, the subject's sitting or walking movements, or other everyday movements, and is typically recorded by attaching multiple sensors to the subject. Based on this, the inverse dynamics analysis unit 13 estimates the fatigue of each muscle group of the subject and estimates the subject's energy consumption. The inverse dynamics analysis performed by the inverse dynamics analysis unit 13 typically uses "AnyBody" (registered trademark). "AnyBody" is a musculoskeletal mechanics analysis software developed at Aalborg University in Denmark and widely used worldwide. When a human musculoskeletal model is subjected to movement, it calculates the forces acting on each part of the human body (muscle activity, muscle strength and antagonistic muscle strength, tendon elastic energy, joint force and joint moment, etc.) using inverse dynamics analysis. However, the inverse dynamics analysis performed by the inverse dynamics analysis unit 13 is not limited to this, and other commercially available software may also be used.
[0043] The output unit 14 typically displays the analysis results from the inverse dynamics analysis unit 13 on the LCD 5.
[0044] The first embodiment has been described above. The first embodiment has the following features.
[0045] A simulation device 1 (simulation system) for a musculoskeletal model including multiple muscle groups arranged along the skeleton includes a measurement result acquisition unit 11 (measurement result acquisition means) that acquires a first measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to the subject's SFL (first anatomy train), and a second measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to the subject's SBL (second anatomy train); and an adjustment unit 12 (adjustment means) that performs an adjustment process to adjust the muscle strength (muscle group parameter) of at least one of the multiple muscle groups belonging to the SFL and the multiple muscle groups belonging to the SBL in the musculoskeletal model based on a comparison result of the first measurement result and the second measurement result. With the above configuration, the accuracy of the simulation of the musculoskeletal model, taking into account the variability in how muscles are attached to each individual, can be efficiently improved.
[0046] Furthermore, the adjustment unit 12 performs an adjustment process based on the ratio of the first measurement result to the second measurement result. With the above configuration, the musculoskeletal model can be customized according to the ratio of the first measurement result to the second measurement result.
[0047] Furthermore, the adjustment unit 12 performs an adjustment process so that the ratio of the muscle strength of multiple muscle groups belonging to the SFL and the muscle strength of multiple muscle groups belonging to the SBL in the musculoskeletal model approaches the ratio of the subject's first measurement result to the second measurement result. With the above configuration, parameter adjustment is performed for each anatomical line by focusing on the discrepancy between the subject's measured ratio and the model's ratio.
[0048] (Second Embodiment) Next, a second embodiment of this disclosure will be described. The following description will focus on the differences between this embodiment and the first embodiment described above, omitting any redundant explanations.
[0049] In the first embodiment described above, the adjustment unit 12 adjusts at least one of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model selected by the musculoskeletal model 10 so that the ratio of the muscle strengths of the muscle groups belonging to the SFL and the muscle strengths of the muscle groups belonging to the SBL in the musculoskeletal model matches the measured ratio of the subject.
[0050] Instead, in the adjustment process of this embodiment, it is determined which side the subject's measured ratio deviates from the reference ratio, and a predetermined multiplier is applied to the muscle strength of multiple muscle groups belonging to the anatomical train on the deviating side. For example, if the subject's measured ratio is 3.2:2, it can be said that the subject's measured ratio deviates from the reference ratio towards extension, so the adjustment unit 12 performs an adjustment process in which a predetermined multiplier is applied to the muscle strength of multiple muscle groups belonging to the SFL in the musculoskeletal model.
[0051] Specifically, the adjustment unit 12 determines that if the variable R obtained by the following formula is positive, the subject's measured ratio deviates from the standard ratio towards extension, and if the variable R is negative, the subject's measured ratio deviates from the standard ratio towards flexion. However, in the following formula, T means knee joint torque, ext means extension, flx means flexion, measured means measured value, and standard means model standard value (model initial value). Therefore, for example, Text.measured means the measured value of knee joint torque during extension, and Tflx.standard means the model standard value (model initial value) of knee joint torque during flexion.
[0052]
number
[0053] The adjustment unit 12 uniformly multiplies the muscle strength of multiple muscle groups belonging to the SFL in the musculoskeletal model by 1.2 if the variable R is positive, i.e., the subject's measured ratio deviates from the reference ratio towards the extension side. Similarly, the adjustment unit 12 uniformly multiplies the muscle strength of multiple muscle groups belonging to the SBL in the musculoskeletal model by 1.2 if the variable R is negative, i.e., the subject's measured ratio deviates from the reference ratio towards the flexion side. By uniformly multiplying the muscle strength of multiple muscle groups belonging to the SFL or SBL by a predetermined multiplier depending on whether the variable R is positive or negative, the adjustment process by the adjustment unit 12 is simplified.
[0054] The present invention has been described in detail above based on embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible without departing from the spirit of the invention.
[0055] For example, in the first and second embodiments described above, the same multiplier is applied to the muscle strength of multiple muscle groups belonging to a specific anatomical train of the musculoskeletal model. However, instead, the multiplier applied to the muscle strength may be different for each of the multiple muscle groups, depending on the degree of contribution of each muscle group to movement during muscle strength measurement.
[0056] Furthermore, in the first and second embodiments described above, muscle strength measurements may be performed individually on the right and left halves of the subject's body, and the adjustment unit 12 may perform the above adjustment process individually on the right and left halves of the musculoskeletal model, respectively.
[0057] Furthermore, in the first and second embodiments described above, the first and second anatomy trains were assumed to be SFL and SBL. As mentioned above, the first and second anatomy trains may also be FFL and BFL. In this case, the first measurement result, which is the result of muscle strength measurement using multiple muscle groups belonging to the first anatomy train, is typically the result of shoulder joint internal rotation force measurement. Shoulder joint internal rotation force is typically the joint torque at the shoulder joint during shoulder joint internal rotation. The second measurement result, which is the result of muscle strength measurement using multiple muscle groups belonging to the second anatomy train, is typically the result of shoulder joint external rotation force measurement. Shoulder joint external rotation force is typically the joint torque at the shoulder joint during shoulder joint external rotation. [Explanation of Symbols]
[0058] 1. Simulation device 2 processors 3 memory 4. Communication Interface 5 LCD 6 Input Interfaces 10. Musculoskeletal Model Selection Section 11 Measurement result acquisition section 12 Adjustment section 13 Inverse dynamics analysis section 14 Output section 15 Musculoskeletal Model Database 16 Musculoskeletal Models 16a AM50 model 16b GM model 16c JAMA50
Claims
1. A simulation system for a musculoskeletal model that includes multiple muscle regions arranged along the skeleton, Measurement result acquisition means for acquiring a first measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to a first anatomy train of a subject, and a second measurement result, which is the result of measuring muscle strength using multiple muscle groups belonging to a second anatomy train that are antagonistic to the first anatomy train of the subject. Based on the comparison results of the first measurement result and the second measurement result, an adjustment means performs an adjustment process in the musculoskeletal model to adjust the muscle region parameters of at least one of the plurality of muscle regions belonging to the first anatomy train and the plurality of muscle regions belonging to the second anatomy train. including, Simulation system.
2. The aforementioned adjustment means is Based on the ratio of the first measurement result to the second measurement result, the adjustment process is performed. The simulation system according to claim 1.
3. The aforementioned adjustment means is The adjustment process is performed such that the ratio of the muscle region parameters of the plurality of muscle regions belonging to the first anatomy train and the muscle region parameters of the plurality of muscle regions belonging to the second anatomy train in the musculoskeletal model approaches the ratio of the first measurement result to the second measurement result of the subject. The simulation system according to claim 2.
4. The first anatomical train is the superficial front line (SFL), and the second anatomical train is the superficial back line (SBL). A simulation system according to any one of claims 1 to 3.
5. The first anatomical train is the front functional line (FFL), and the second anatomical train is the back functional line (BFL). A simulation system according to any one of claims 1 to 3.