An exoskeleton rigidity dynamic response evaluation method based on plantar excitation characteristics

Abstract

The present application relates to the technical field of evaluating exoskeleton rigidity, and discloses an exoskeleton rigidity dynamic response evaluation method based on foot bottom excitation characteristics. The exoskeleton rigidity dynamic response evaluation method based on foot bottom excitation characteristics measures the current foot bottom excitation characteristic parameters (vertical contact force, vertical settlement distance and horizontal slip distance) by deploying a composite sensing gasket on the foot bottom, and effectively separates the ground self deformation from the exoskeleton structure deformation. On this basis, the current foot bottom excitation characteristic parameters are used to query a geological correction lookup table to determine the current correction coefficient, and the coupling relationship between the ground and the structure is converted into the product of the rigidity reference value and the current correction coefficient, so as to quickly predict the dynamic response value of the exoskeleton on the current terrain. By comparing the deviation between the predicted value and the measured value, not only can the rigidity deficiency be judged, but also the rigidity excess can be identified, thereby providing a basis for targeted optimization of the exoskeleton structure.

Description

Technical Field

[0001] This invention relates to the technical field of evaluating exoskeleton rigidity, and in particular to a method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics. Background Technology

[0002] In construction and operations such as power grid development in mountainous areas and wilderness rescue, workers often need to carry heavy materials and cross ravines, steep steps, and irregular obstacles. Exoskeletons can effectively support the human body, transfer loads, significantly reduce the physical exertion of workers, and improve work efficiency and safety.

[0003] Currently, performance testing methods for exoskeleton equipment mainly focus on two scenarios: one is static structural strength testing in a laboratory using equipment such as universal testing machines; the other is dynamic mechanical analysis by collecting human gait data on flat ground or a treadmill. However, the construction environment in mountainous areas differs fundamentally from the above testing scenarios. During high-intensity actions such as crossing ditches or leaping up stairs, the exoskeleton structure will be subjected to multiple dynamic loads, including instantaneous impact, severe vibration, and rapid deformation recovery.

[0004] Furthermore, mountainous terrain is not a rigid platform like in a laboratory. The soil and rocks at the edges of ravines may be soft and prone to collapse, and there may be loose rocks sliding on the surface of steps. When the exoskeleton's supporting legs act on non-rigid ground, the deformation of the ground itself will couple with the exoskeleton structure.

[0005] Existing strain and acceleration measurement methods cannot distinguish whether the stress changes measured are from the actual deformation of the exoskeleton structure or from a false response caused by ground subsidence or slippage, resulting in distorted test data and an inability to accurately assess the true rigidity of the exoskeleton. Summary of the Invention

[0006] Therefore, this invention aims to overcome the technical problem of being unable to effectively distinguish between the actual deformation of the exoskeleton structure and the false response caused by ground collapse or slippage in complex terrain. It proposes an exoskeleton rigidity dynamic response evaluation method based on plantar excitation characteristics. By deploying composite sensing pads on the soles of the feet and measuring the current plantar excitation characteristic parameters, the deformation of the ground itself is separated from the exoskeleton structure deformation signal, thereby eliminating ground-bone coupling interference and improving the accuracy and reliability of the rigidity evaluation of the exoskeleton in complex mountainous working environments.

[0007] To address the aforementioned technical problems, this invention provides a method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics, comprising:

[0008] Strain sensors are deployed in the stress concentration areas of the exoskeleton to be tested, acceleration sensors are deployed at vibration transmission nodes, and composite sensing pads are deployed at the bottom of the boot cover.

[0009] After the tester wears the exoskeleton, he performs a hurdle movement on the ground and acquires a first signal set; wherein the first signal set includes signals collected by strain sensors, acceleration sensors and composite sensing pads throughout the hurdle movement.

[0010] Based on the signals collected by the composite sensor pad, the current plantar excitation characteristic parameters are determined, and the current correction coefficient is determined by matching the current plantar excitation characteristic parameters with the geological correction lookup table.

[0011] Based on the reference exoskeleton dynamic response parameters of the rigid reference ground in the geological correction lookup table and the current correction coefficient, determine the predicted value of the exoskeleton dynamic response;

[0012] Based on the signals collected by strain sensors and accelerometers, the measured values ​​of the exoskeleton's dynamic response are determined, and the rigidity of the exoskeleton is evaluated based on the deviation between the predicted values ​​and the measured values ​​of the exoskeleton's dynamic response.

[0013] Preferably, the method for determining the current plantar excitation characteristic parameters includes:

[0014] Based on the vertical contact force waveform and vertical settlement waveform throughout the entire hopping motion, identify the first start point and the first end point of the take-off phase, as well as the second start point and the second end point of the landing phase.

[0015] The vertical settlement distance at the first starting point is taken as the initial vertical settlement amount for the take-off phase;

[0016] Extract the shape features of the vertical settlement waveform from the first starting point to the first ending point as the shape of the settlement curve during the take-off phase;

[0017] The maximum value in the vertical settlement waveform from the first starting point to the first ending point is taken as the maximum vertical settlement in the take-off phase, and the corresponding time point is marked as the maximum time point in the take-off phase.

[0018] Calculate the average settlement velocity during the take-off phase based on the initial vertical settlement at the first starting point and the initial vertical settlement during the take-off phase, as well as the maximum vertical settlement at the maximum time point and the maximum vertical settlement during the take-off phase.

[0019] The maximum value in the vertical settlement waveform from the second starting point to the second ending point is taken as the maximum vertical settlement during the landing phase.

[0020] Traverse the horizontal sliding waveform from the second starting point to the second ending point: when the absolute value of the horizontal sliding distance is greater than the second preset threshold, horizontal sliding has occurred; otherwise, horizontal sliding has not occurred.

[0021] Preferably, the method for determining the first starting point, the first ending point, the second starting point, and the second ending point includes:

[0022] The average value of the vertical contact force waveform before the first continuous rise of the vertical contact force is taken as the standing steady-state contact force.

[0023] When the vertical contact force first increases continuously and is 1.1 times the steady-state contact force, the corresponding time point is marked as the first starting point of the take-off phase.

[0024] When the vertical contact force first decreases and is less than or equal to the first preset threshold, the corresponding time point is marked as the first end point of the take-off phase.

[0025] When the vertical contact force first exceeds the third preset threshold after the first end point, the corresponding time point is marked as the second start point of the landing phase;

[0026] After the second starting point, when both the vertical contact force and the vertical settlement distance tend to stabilize, the corresponding time point is marked as the second ending point of the landing phase.

[0027] Preferably, the method for determining the stability of the vertical contact force is as follows:

[0028] When the standard deviation of the vertical contact force is less than 2% or 10N of the standing steady-state contact force within the first time window, the vertical contact force tends to stabilize.

[0029] The method for determining the stability of the vertical settlement distance:

[0030] When the difference between the maximum and minimum vertical settlement distances is less than 1 mm within the second time window, the vertical settlement distance tends to stabilize.

[0031] Preferably, the geological correction lookup table includes:

[0032] The reference geological types include at least rigid reference ground, compacted soil pavement, loose soil-rock mixture surface and wet mud surface;

[0033] Correction factors, which include at least the peak stress correction factor, vibration frequency correction factor, and deformation recovery time correction factor for each reference geological type;

[0034] The reference exoskeleton dynamic response parameters include at least the peak stress of the supporting leg, the frame vibration frequency, and the deformation recovery time for each reference geological type.

[0035] The reference plantar excitation characteristic parameters include at least the maximum vertical settlement during the take-off phase, the average settlement velocity during the take-off phase, the shape of the settlement curve during the take-off phase, the maximum vertical settlement during the landing phase, and whether horizontal slippage occurs for each reference geological type.

[0036] Preferably, the method for determining the current correction coefficient includes:

[0037] Compare the current plantar excitation characteristic parameters with the reference plantar excitation characteristic parameters for each reference geological type in the geological correction lookup table:

[0038] If the current plantar excitation characteristic parameters belong to the range of reference crossing action execution parameters for a certain reference geological type, the correction coefficient corresponding to the reference geological type shall be used as the current correction coefficient;

[0039] Otherwise, based on the two sets of reference straddle motion execution parameters adjacent to the current plantar excitation characteristic parameters and their corresponding correction coefficients, the interpolated correction coefficients are calculated using a linear interpolation method, and the interpolated correction coefficients are used as the current correction coefficients.

[0040] Preferably, the current correction coefficient includes the following formula:

[0041] ;

[0042] In the formula, This is the current correction factor; This is the correction factor corresponding to geological type A; This is the correction factor corresponding to geological type B; The reference parameters for the crossing action are for geological type B. The reference parameters for the crossing action are for geological type A. These are the current plantar excitation characteristic parameters, and .

[0043] Preferably, the method for determining the predicted dynamic response value of the exoskeleton includes:

[0044] The product of the peak stress of the support leg on the rigid reference ground and the peak stress correction factor in the current correction factor is determined as the predicted peak stress value of the support leg.

[0045] The predicted frame vibration frequency is determined by multiplying the frame vibration frequency of the rigid reference ground with the vibration frequency correction factor in the current correction factor.

[0046] The deformation recovery time is determined by multiplying the deformation recovery time of the rigid reference ground by the deformation recovery time correction factor in the current correction factor.

[0047] Preferably, the method for determining the measured values ​​of the exoskeleton's dynamic response includes:

[0048] A stress curve showing the change of strain in the stress concentration region over time is plotted with time as the horizontal axis and strain in the stress concentration region as the vertical axis. The maximum strain value between the first starting point and the first ending point in the stress curve is taken as the measured value of the support leg stress peak during the take-off phase.

[0049] The maximum value of the strain between the second starting point and the second ending point is taken as the first strain, and the corresponding time point is marked as the first time. When the strain reaches the first strain and firstly drops to 10% of the first strain, the corresponding time point is marked as the second time. The difference between the second time and the first time is taken as the measured deformation recovery time during the landing phase.

[0050] Acquire the acceleration signal between the first end point and the second start point; perform spectral analysis on the acceleration signal to obtain a spectrum diagram; take the frequency with the largest amplitude in the spectrum diagram as the measured frequency of frame vibration during the take-off phase.

[0051] Preferably, the method for assessing the rigidity of the exoskeleton includes:

[0052] When the peak stress deviation, vibration frequency deviation, and recovery time deviation are all within the deviation threshold, the exoskeleton's rigid dynamic response is normal.

[0053] When the peak stress deviation exceeds the deviation threshold, the exoskeleton is not rigid enough.

[0054] When the peak stress deviation is less than the deviation threshold, the exoskeleton is excessively rigid.

[0055] When the vibration frequency deviation exceeds the deviation threshold, the exoskeleton becomes excessively rigid.

[0056] When the vibration frequency deviation is less than the deviation threshold, the exoskeleton is not rigid enough.

[0057] When the recovery time deviation exceeds the deviation threshold, the exoskeleton rigidity is insufficient.

[0058] When the recovery time deviation is less than the deviation threshold, the exoskeleton is excessively rigid.

[0059] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0060] The exoskeleton rigidity dynamic response evaluation method based on plantar excitation characteristics described in this invention effectively separates ground deformation from exoskeleton structural deformation by deploying composite sensing pads on the soles of the feet to measure current plantar excitation characteristic parameters (vertical contact force, vertical settlement distance, and horizontal sliding distance). Based on this, a geological correction lookup table is consulted using the current plantar excitation characteristic parameters to determine the current correction coefficient. The coupling relationship between the ground and the structure is then transformed into the product of the rigidity benchmark value and the current correction coefficient, thereby rapidly predicting the dynamic response value of the exoskeleton on the current terrain. By comparing the deviation between the predicted and measured values, not only can insufficient rigidity be identified, but also excessive rigidity can be determined, providing a basis for targeted optimization of the exoskeleton structure. Attached Figure Description

[0061] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0062] Figure 1 This is a schematic diagram of the process for evaluating the dynamic response of an exoskeleton based on plantar excitation features in an embodiment of the present invention.

[0063] Figure 2 This is a schematic diagram of a geological correction lookup table in an embodiment of the present invention. Detailed Implementation

[0064] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0065] Example 1: A method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics.

[0066] refer to Figure 1 The exoskeleton rigidity dynamic response evaluation method based on plantar excitation characteristics in this embodiment includes steps SS1 to SS5.

[0067] Step SS1: Deploy strain sensors in the stress concentration areas of the exoskeleton to be tested, deploy acceleration sensors at vibration transmission nodes, and deploy composite sensing pads at the bottom of the boot cover.

[0068] When applied, step SS1 includes steps SS11 to SS13.

[0069] Step SS11: Deploy strain sensors in the stress concentration areas of the exoskeleton to be tested.

[0070] In application, strain sensors are attached to the stress concentration areas of the left and right support leg frames of the exoskeleton under test. These strain sensors are used to measure the strain in the stress concentration areas of the exoskeleton.

[0071] Stress concentration areas are generally located in areas with abrupt changes in cross-section, openings, welds, or bolted connections, and at least include: the middle section of the thigh frame of the supporting leg, the middle section of the lower leg frame of the supporting leg, and the frame connection near the knee joint pivot. Specifically, the middle section and its lower part of the thigh frame of the supporting leg are the areas that bear the greatest bending moment, the middle section of the lower leg frame of the supporting leg is the area that bears the combined axial compression and bending loads, and the frame connection near the knee joint pivot is the area that bears torque and shear force.

[0072] In some embodiments, three strain sensors can be attached to each stress concentration area. The three strain sensors intersect, with the sensitive grid direction of the first strain sensor parallel to the frame axis; the sensitive grid direction of the second strain sensor perpendicular to the frame axis; and the sensitive grid direction of the third strain sensor at a 45° angle to the frame axis. The first strain sensor measures the longitudinal strain of the frame under axial compression or tension. For example, during takeoff, the supporting leg is compressed, and the first strain sensor measures a negative compressive strain. The second strain sensor measures the lateral strain of the frame due to bending or torsion. When the frame bends, one side is under tension and the other under compression, and the lateral strain has a Poisson's ratio relationship with the longitudinal strain. The third strain sensor measures the shear strain of the frame under shear loads. For example, the torque at the knee joint pivot during takeoff causes principal strain in the frame at a 45° angle.

[0073] Step SS12: Deploy accelerometers at the vibration transmission nodes of the exoskeleton to be tested.

[0074] In application, a triaxial accelerometer is installed at each vibration transmission node of the left and right support leg frames of the exoskeleton under test. The accelerometers are used to measure the acceleration signals at the vibration transmission nodes of the exoskeleton.

[0075] In practical applications, vibration transmission nodes are generally located at geometric abrupt changes and connection points of the frame, including at least the knee joint pivot and the hip joint pivot. Furthermore, a triaxial accelerometer is installed at the knee and hip joint pivots of both the left and right support leg frames.

[0076] Step SS13: Deploy composite sensing pads at the bottom of the boot cover of the exoskeleton to be tested.

[0077] In application, composite sensing pads are deployed at the bottom of the left and right boot covers of the exoskeleton under test. These composite sensing pads are used to measure the vertical contact force between the sole of the foot and the ground, the vertical settlement distance, and the horizontal sliding distance.

[0078] In application, the composite sensing pad includes a force sensor layer, a laser rangefinder probe layer, and a flexible protective layer arranged in sequence.

[0079] The force sensor layer measures the vertical contact force between the foot and the ground, with a range of 0 to 5000 Newtons. The laser rangefinder layer consists of two pairs of miniature laser rangefinders, one facing forward and the other downward, used to measure the horizontal slip distance and vertical settlement distance of the foot relative to the initial contact point. The flexible protective layer is made of a flexible material to adapt to irregular terrain.

[0080] Step SS2: After the test subject puts on the exoskeleton, he performs a hopping motion on the ground and acquires the first signal set.

[0081] In application, the hurdle maneuver includes specifying the take-off foot, hurdle height, hurdle span, required torso posture during flight, and landing foot. For example: the take-off foot is the right foot; the hurdle height is 0.3m to 0.5m; the hurdle span is 0.6m to 0.8m; the torso posture during flight is upright with arms naturally extended; and the landing foot is the left foot. Specifically, after donning the exoskeleton, the test subject first uses their right leg as the supporting leg to generate momentum for a take-off, leaping across the ditch, and finally landing on the opposite bank using their left leg as the supporting leg.

[0082] In practical applications, the first signal set includes signals collected by strain sensors, acceleration sensors, and composite sensing pads throughout the entire process of the action.

[0083] Step SS3: Based on the signal collected by the composite sensor pad, determine the plantar excitation characteristic parameters, and match the current plantar excitation characteristic parameters with the geological correction lookup table to determine the current correction coefficient.

[0084] When applied, the plantar excitation characteristic parameters include the maximum vertical settlement during the take-off phase, the average settlement velocity during the take-off phase, the shape of the settlement curve during the take-off phase, the maximum vertical settlement during the landing phase, and whether horizontal slippage occurs.

[0085] Furthermore, the method for determining the plantar excitation characteristic parameters includes steps SS31 to SS37.

[0086] Step SS31: Based on the vertical contact force waveform and vertical settlement waveform throughout the entire crossing action, identify the first start point and the first end point of the take-off phase, as well as the second start point and the second end point of the landing phase.

[0087] In application, the vertical settlement waveform is plotted as a curve showing the change of vertical settlement distance over time, with time as the horizontal axis and vertical settlement distance as the vertical axis. The vertical contact force waveform is plotted as a curve showing the change of vertical contact force over time, with time as the horizontal axis and vertical contact force as the vertical axis.

[0088] In practical applications, the order of the first starting point, the first ending point, the second starting point, and the second ending point on the time axis is as follows: first starting point, first ending point, second starting point, and second ending point.

[0089] In actual implementation, the jump phase is from the first starting point to the first ending point; the flight phase is from the first ending point to the second starting point; and the landing phase is from the second starting point to the second ending point.

[0090] In some embodiments, step SS31 includes steps SS311 to SS315.

[0091] Step SS311: Go through the vertical contact force waveform and take the average value of the vertical contact force waveform before the first continuous rise of the vertical contact force as the standing steady-state contact force.

[0092] When applying this method, the vertical contact force waveform is traversed. Before the vertical contact force first rises continuously, i.e. before the crossing action begins, a stable vertical contact force waveform is taken as the vertical contact force waveform during the standing period. The average value of the vertical contact force waveform during the standing period is taken as the standing steady-state contact force.

[0093] Step SS312: When the vertical contact force first increases continuously and is 1.1 times the steady-state contact force, mark the corresponding time point as the first starting point of the take-off phase.

[0094] Step SS313: When the vertical contact force first decreases and the vertical contact force is less than or equal to the first preset threshold, mark the corresponding time point as the first end point of the jump phase.

[0095] When applied, the first preset threshold is 5% or 20N of the standing steady-state contact force.

[0096] Step SS314: After the first end point, when the vertical contact force first exceeds the third preset threshold, mark the corresponding time point as the second start point of the landing phase.

[0097] When applied, the vertical contact force waveform is scanned from the first end point of the take-off phase: when the vertical contact force first exceeds the third preset threshold, the corresponding time point is marked as the second start point of the landing phase.

[0098] In practical applications, the third preset threshold can be adjusted based on the noise level of the composite sensing pad and the weight of the tester. Specifically, the third preset threshold can be between 5N and 20N. Further, the third preset threshold can be 10N.

[0099] Step SS315: After the second starting point, when both the vertical contact force and the vertical settlement distance tend to stabilize, mark the corresponding time point as the second end point of the landing phase.

[0100] When applying the application, the first time window can be 0.2s, and the second time window can be 0.1s.

[0101] In practical applications, when the standard deviation of the vertical contact force is less than 2% or 10N of the steady-state contact force in the first time window, and the difference between the maximum and minimum vertical settlement distance is less than 1mm in the second time window, the corresponding time point is marked as the second end point of the landing phase.

[0102] Step SS32: Use the vertical settlement distance of the first starting point as the initial vertical settlement amount for the take-off phase.

[0103] Step SS33: Extract the shape features of the vertical settlement waveform from the first starting point to the first ending point as the shape of the settlement curve in the take-off phase.

[0104] When applied, the shape characteristics are either fast at first and then stable, continuous linear, or accelerated growth.

[0105] In practical applications, the "fast-then-stable" type indicates that the vertical settlement distance initially increases during the initial jump phase and then stabilizes. When the difference between the maximum and minimum vertical settlement distances within the second time window is less than 1 mm, it indicates that the vertical settlement distance is stabilizing. The "continuously linear" type indicates that the vertical settlement distance increases at an approximately uniform rate throughout the entire jump phase. The "accelerated growth" type indicates that the rate of increase in vertical settlement distance continuously accelerates over time.

[0106] Step SS34: Take the maximum value of the vertical settlement waveform from the first starting point to the first ending point as the maximum vertical settlement in the take-off phase, and mark the corresponding time point as the maximum time point in the take-off phase.

[0107] Step SS35: Calculate the average settlement velocity during the take-off phase based on the initial vertical settlement at the first starting point and the initial vertical settlement during the take-off phase, as well as the maximum vertical settlement at the maximum time point and the maximum vertical settlement during the take-off phase.

[0108] Step SS36: Take the maximum value of the vertical settlement waveform from the second starting point to the second ending point as the maximum vertical settlement during the landing phase.

[0109] Step SS37: Traverse the horizontal sliding waveform from the second starting point to the second ending point: when the absolute value of the horizontal sliding distance is greater than the second preset threshold, horizontal sliding has occurred; otherwise, horizontal sliding has not occurred.

[0110] In application, the horizontal sliding waveform is a curve plotted with time as the horizontal axis and horizontal sliding distance as the vertical axis, showing how the horizontal sliding distance changes over time.

[0111] In practical applications, the horizontal sliding waveform from the second starting point to the second ending point is traversed: when the absolute value of any horizontal sliding distance is greater than the second preset threshold, horizontal sliding has occurred; otherwise, horizontal sliding has not occurred.

[0112] In practice, the second preset threshold can be adjusted according to different ground types. For example, on wet and slippery mud surfaces, even small slippage can significantly affect the stress, so the second preset threshold can be set to 3mm; on compacted soil surfaces, the second preset threshold can be set to 8mm.

[0113] refer to Figure 2 In practical applications, the geological correction lookup table includes: reference geological type, correction coefficient, reference exoskeleton dynamic response parameters, and reference plantar excitation characteristic parameters.

[0114] The reference geological types include at least a rigid reference surface, compacted soil pavement, loose soil-rock mixture surface, and wet mud surface. The rigid reference surface can be a steel plate platform with a thickness greater than 50 mm. A rigid block is placed on the steel plate platform, with the bottom area of ​​the rigid block larger than the bottom area of ​​the boot cover, and the total mass of the rigid block greater than or equal to the weight of the tester. A maximum expected vertical contact force of 3000 N is applied to the rigid block, and the vertical settlement distance of the bottom surface of the rigid block is measured simultaneously; the vertical settlement distance is less than 0.1 mm.

[0115] The correction factors include at least the peak stress correction factor, vibration frequency correction factor, and deformation recovery time correction factor for each reference geological type. Specifically, the correction factor for the rigid reference ground is 1. The correction factors for other reference geological types are determined based on the ratio of their reference exoskeleton dynamic response parameters to the reference exoskeleton dynamic response parameters of the rigid reference ground.

[0116] The reference exoskeleton dynamic response parameters should include at least the peak stress of the supporting legs, the frame vibration frequency, and the deformation recovery time for each reference geological type.

[0117] The reference plantar excitation characteristic parameters include at least the maximum vertical settlement during the take-off phase, the average settlement velocity during the take-off phase, the shape of the settlement curve during the take-off phase, the maximum vertical settlement during the landing phase, and whether horizontal slippage occurs for each reference geological type. Furthermore, each reference plantar excitation characteristic parameter represents a typical range value.

[0118] Furthermore, the current method for determining the correction factor includes steps SS381 to SS383.

[0119] Step SS381: Compare the current plantar excitation feature parameters with the reference plantar excitation feature parameters of each reference geological type in the geological correction lookup table.

[0120] Step SS382: If the current plantar excitation feature parameter belongs to the reference crossing action execution parameter range of a certain reference geological type, the correction coefficient corresponding to the reference geological type is used as the current correction coefficient; otherwise, proceed to step SS383.

[0121] Step SS383: Based on the two sets of reference straddle motion execution parameters adjacent to the current plantar excitation characteristic parameters and their corresponding correction coefficients, calculate the interpolated correction coefficients using the linear interpolation method, and use the interpolated correction coefficients as the current correction coefficients.

[0122] For example, if the current plantar excitation characteristic parameters are between the reference crossing action execution parameters for geological type A and the reference crossing action execution parameters for geological type B, then the current correction coefficient is determined according to the following formula:

[0123] ;

[0124] In the formula, This is the current correction factor, such as the peak stress correction factor, vibration frequency correction factor, or deformation recovery time correction factor; This is the correction factor corresponding to geological type A; This is the correction factor corresponding to geological type B; The reference parameters for the crossing action are for geological type B. The reference parameters for the crossing action are for geological type A. These are the current plantar excitation characteristic parameters, and .

[0125] Step SS4: Determine the predicted value of the exoskeleton dynamic response based on the reference exoskeleton dynamic response parameters of the rigid reference ground in the geological correction lookup table and the current correction coefficient.

[0126] When applied, the predicted values ​​of the exoskeleton's dynamic response include the predicted peak stress value of the supporting leg, the predicted frequency of frame vibration, and the predicted time of deformation recovery.

[0127] In practical applications, the peak stress of the support leg on the rigid reference ground is multiplied by the peak stress correction factor in the current correction factor to determine the predicted peak stress value of the support leg; the frame vibration frequency on the rigid reference ground is multiplied by the vibration frequency correction factor in the current correction factor to determine the predicted frame vibration frequency; and the deformation recovery time on the rigid reference ground is multiplied by the deformation recovery time correction factor in the current correction factor to determine the predicted deformation recovery time.

[0128] Step SS5: Based on the signals collected by the strain sensor and accelerometer, determine the measured values ​​of the exoskeleton's dynamic response, and assess the rigidity of the exoskeleton based on the deviation between the predicted values ​​of the exoskeleton's dynamic response and the measured values ​​of the exoskeleton's dynamic response.

[0129] When applied, the measured values ​​of the exoskeleton's dynamic response should include at least the measured values ​​of the peak stress of the supporting leg, the measured frequency of frame vibration, and the measured time of deformation recovery.

[0130] The method for determining the measured values ​​of the exoskeleton's dynamic response includes steps SS51 to SS52. Further, the method for determining the measured values ​​of the exoskeleton's dynamic response includes steps SS53 to SS55. Even further, the method for determining the measured values ​​of the exoskeleton's dynamic response includes steps SS56 to SS59.

[0131] Step SS51: Plot the stress curve of the stress concentration region as a function of time, with time as the horizontal axis and the strain of the stress concentration region as the vertical axis.

[0132] Step SS52: Take the maximum value of the strain between the first starting point and the first ending point in the stress curve as the measured value of the support leg stress peak during the take-off phase.

[0133] Step SS53: Obtain the acceleration signal between the first end point and the second start point.

[0134] When applied, the acceleration signal is a vertical acceleration signal.

[0135] Step SS54: Perform spectral analysis on the acceleration signal to obtain the spectrum diagram.

[0136] In application, the acceleration signal is subjected to spectral analysis, for example, by using Fast Fourier Transform to convert the acceleration signal in the time domain into the frequency domain and obtain the spectrum.

[0137] In practical applications, the sampling frequency should be at least five times the predicted frequency of frame vibration, which can be set to 500Hz to 2000Hz; the number of FFT analysis points should be an integer power of 2, such as 1024 or 2048 points; a Hanning window can be used to suppress spectral leakage; and the overlap rate of adjacent data segments can be set to 50%. Those skilled in the art can adjust the parameters according to the actual signal characteristics. For example, the sampling frequency can be set to 1000 Hz, the number of FFT analysis points to 2048, the Hanning window to be used, and the overlap rate of adjacent data segments to 50%.

[0138] Step SS55: Take the frequency with the largest amplitude in the spectrum as the measured frequency of frame vibration during the take-off phase.

[0139] Step SS56: Traverse the strain between the second starting point and the second ending point in the stress curve.

[0140] Step SS57: Take the maximum value of the dependent variable between the second starting point and the second ending point as the first dependent variable, and mark the corresponding time point as the first time.

[0141] Step SS58: When the dependent variable reaches the first dependent variable and then first drops to 10% of the first dependent variable, mark the corresponding time point as the second time point.

[0142] Step SS59: Take the difference between the second time and the first time as the measured deformation recovery time during the landing phase.

[0143] In practical applications, the calculation method for the deviation between the predicted value and the measured value of the exoskeleton's dynamic response includes the following formula:

[0144] ;

[0145] In the formula, For deviation; These are measured values ​​of the exoskeleton's dynamic response, such as the measured peak stress value of the supporting leg, the measured frequency of frame vibration, or the measured time of deformation recovery. These are predicted values ​​for the dynamic response of the exoskeleton, such as the predicted peak stress value of the supporting leg, the predicted frequency of frame vibration, or the predicted time of deformation recovery.

[0146] Furthermore, when the measured value of the exoskeleton's dynamic response is the measured value of the peak stress of the supporting leg, and the predicted value of the exoskeleton's dynamic response is the predicted value of the peak stress of the supporting leg, the deviation is the peak stress deviation; when the measured value of the exoskeleton's dynamic response is the measured frequency of frame vibration, and the predicted value of the exoskeleton's dynamic response is the predicted frequency of frame vibration, the deviation is the vibration frequency deviation; when the measured value of the exoskeleton's dynamic response is the measured deformation recovery time, and the predicted value of the exoskeleton's dynamic response is the predicted deformation recovery time, the deviation is the recovery time deviation.

[0147] In practical implementation, the methods for assessing the rigidity of the exoskeleton include:

[0148] When the peak stress deviation, vibration frequency deviation, and recovery time deviation are all within the deviation threshold, the exoskeleton's rigid dynamic response is normal; otherwise, the exoskeleton's rigid dynamic response is abnormal. The deviation threshold can be adjusted according to the exoskeleton's design requirements and safety factor. In some embodiments, the deviation threshold can be [-10, 10].

[0149] Furthermore, when the peak stress deviation exceeds the deviation threshold, the exoskeleton's rigidity is insufficient, specifically: the exoskeleton frame stiffness is too low, resulting in excessive deformation during takeoff. The exoskeleton's dynamic rigidity response can be optimized by increasing the structural stiffness, for example, by increasing the frame wall thickness, adding reinforcing ribs, or replacing the material with one of higher elastic modulus.

[0150] When the peak stress deviation is less than the deviation threshold, the exoskeleton is excessively rigid, meaning it is too bulky and there is room for weight reduction optimization. The dynamic response of the exoskeleton's rigidity can be optimized by reducing its weight, for example, by reducing wall thickness, adding weight-reducing holes, or replacing it with a low-density material.

[0151] When the vibration frequency deviation exceeds a deviation threshold, the exoskeleton exhibits excessive rigidity, specifically excessive frame stiffness. The dynamic response of the exoskeleton's rigidity can be optimized by reducing its weight, for example, by reducing wall thickness, removing redundant stiffeners, or replacing materials with lower density ones.

[0152] When the vibration frequency deviation is less than the deviation threshold, the exoskeleton lacks rigidity, specifically: the natural frequency of the exoskeleton frame is too low, resulting in poor vibration suppression. The dynamic response of the exoskeleton's rigidity can be optimized by increasing the structural stiffness or reducing its mass, for example, by optimizing the cross-sectional shape, using a truss structure, and reducing weight in non-load-bearing areas.

[0153] When the recovery time deviation exceeds the deviation threshold, the exoskeleton lacks rigidity, specifically exhibiting poor elastic recovery capability and slow rebound after deformation. The dynamic response of the exoskeleton's rigidity can be optimized by improving the elastic recovery capability, for example, by replacing materials with high elastic modulus materials or reducing viscoelastic damping materials.

[0154] When the recovery time deviation is less than the deviation threshold, the exoskeleton is excessively rigid, specifically meaning that the frame material has excessive stiffness and elasticity, and the structure has almost no energy dissipation capacity. The exoskeleton's dynamic response can be optimized by increasing its energy dissipation capacity, for example, by introducing damping elements or appropriately reducing the elastic modulus.

[0155] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0156] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0157] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0158] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0159] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for evaluating the rigid dynamic response of an exoskeleton based on plantar stimulation features, characterized in that, include: Strain sensors are deployed in the stress concentration areas of the exoskeleton to be tested, acceleration sensors are deployed at vibration transmission nodes, and composite sensing pads are deployed at the bottom of the boot cover. After the tester wears the exoskeleton, he performs a hurdle movement on the ground and acquires a first signal set; wherein the first signal set includes signals collected by strain sensors, acceleration sensors and composite sensing pads throughout the hurdle movement. Based on the signals collected by the composite sensor pad, the current plantar excitation characteristic parameters are determined, and the current correction coefficient is determined by matching the current plantar excitation characteristic parameters with the geological correction lookup table. Based on the reference exoskeleton dynamic response parameters of the rigid reference ground in the geological correction lookup table and the current correction coefficient, determine the predicted value of the exoskeleton dynamic response; Based on the signals collected by strain sensors and accelerometers, the measured values ​​of the exoskeleton's dynamic response are determined, and the rigidity of the exoskeleton is evaluated based on the deviation between the predicted values ​​of the exoskeleton's dynamic response and the measured values ​​of the exoskeleton's dynamic response. The method for determining the current plantar excitation characteristic parameters includes: Based on the vertical contact force waveform and vertical settlement waveform throughout the entire hopping motion, identify the first start point and the first end point of the take-off phase, as well as the second start point and the second end point of the landing phase. The vertical settlement distance at the first starting point is taken as the initial vertical settlement amount for the take-off phase; Extract the shape features of the vertical settlement waveform from the first starting point to the first ending point as the shape of the settlement curve during the take-off phase; The maximum value in the vertical settlement waveform from the first starting point to the first ending point is taken as the maximum vertical settlement in the take-off phase, and the corresponding time point is marked as the maximum time point in the take-off phase. Calculate the average settlement velocity during the take-off phase based on the initial vertical settlement at the first starting point and the initial vertical settlement during the take-off phase, as well as the maximum vertical settlement at the maximum time point and the maximum vertical settlement during the take-off phase. The maximum value in the vertical settlement waveform from the second starting point to the second ending point is taken as the maximum vertical settlement during the landing phase. Traverse the horizontal sliding waveform from the second starting point to the second ending point: when the absolute value of the horizontal sliding distance is greater than the second preset threshold, horizontal sliding has occurred; otherwise, horizontal sliding has not occurred.

2. The method of claim 1, wherein the method further comprises: The methods for determining the first starting point, the first ending point, the second starting point, and the second ending point include: The average value of the vertical contact force waveform before the first continuous rise of the vertical contact force is taken as the standing steady-state contact force. When the vertical contact force first increases continuously and is 1.1 times the steady-state contact force, the corresponding time point is marked as the first starting point of the take-off phase. When the vertical contact force first decreases and is less than or equal to the first preset threshold, the corresponding time point is marked as the first end point of the take-off phase. When the vertical contact force first exceeds the third preset threshold after the first end point, the corresponding time point is marked as the second start point of the landing phase; After the second starting point, when both the vertical contact force and the vertical settlement distance tend to stabilize, the corresponding time point is marked as the second ending point of the landing phase.

3. The method of claim 2, wherein the method further comprises: The method for determining the stability of the vertical contact force: When the standard deviation of the vertical contact force is less than 2% or 10N of the standing steady-state contact force within the first time window, the vertical contact force tends to stabilize. The method for determining the stability of the vertical settlement distance: When the difference between the maximum and minimum vertical settlement distances is less than 1 mm within the second time window, the vertical settlement distance tends to stabilize.

4. The method of claim 1, wherein the method further comprises: The geological correction lookup table includes: The reference geological types include at least rigid reference ground, compacted soil pavement, loose soil-rock mixture surface and wet mud surface; Correction factors, which include at least the peak stress correction factor, vibration frequency correction factor, and deformation recovery time correction factor for each reference geological type; The reference exoskeleton dynamic response parameters include at least the peak stress of the supporting leg, the frame vibration frequency, and the deformation recovery time for each reference geological type. The reference plantar excitation characteristic parameters include at least the maximum vertical settlement during the take-off phase, the average settlement velocity during the take-off phase, the shape of the settlement curve during the take-off phase, the maximum vertical settlement during the landing phase, and whether horizontal slippage occurs for each reference geological type.

5. The method of claim 4, wherein the method further comprises: The method for determining the current correction factor includes: Compare the current plantar excitation characteristic parameters with the reference plantar excitation characteristic parameters for each reference geological type in the geological correction lookup table: If the current plantar excitation characteristic parameters belong to the range of reference crossing action execution parameters for a certain reference geological type, the correction coefficient corresponding to the reference geological type shall be used as the current correction coefficient; Otherwise, based on the two sets of reference straddle motion execution parameters adjacent to the current plantar excitation characteristic parameters and their corresponding correction coefficients, the interpolated correction coefficients are calculated using a linear interpolation method, and the interpolated correction coefficients are used as the current correction coefficients.

6. The method of claim 5, wherein the evaluation of the rigid dynamic response of the exoskeleton based on plantar stimulation features is characterized by, The current correction factor includes the following formula: ； In the formula, This is the current correction factor; This is the correction factor corresponding to geological type A; This is the correction factor corresponding to geological type B; The reference parameters for the crossing action are for geological type B. The reference parameters for the crossing action are for geological type A. These are the current plantar excitation characteristic parameters, and .

7. The method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics according to claim 1, characterized in that, The method for determining the predicted dynamic response value of the exoskeleton includes: The product of the peak stress of the support leg on the rigid reference ground and the peak stress correction factor in the current correction factor is determined as the predicted peak stress value of the support leg. The predicted frame vibration frequency is determined by multiplying the frame vibration frequency of the rigid reference ground with the vibration frequency correction factor in the current correction factor. The deformation recovery time is determined by multiplying the deformation recovery time of the rigid reference ground by the deformation recovery time correction factor in the current correction factor.

8. The method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics according to claim 2, characterized in that, The method for determining the measured values ​​of the exoskeleton's dynamic response includes: A stress curve showing the change of strain in the stress concentration region over time is plotted with time as the horizontal axis and strain in the stress concentration region as the vertical axis. The maximum strain value between the first starting point and the first ending point in the stress curve is taken as the measured value of the support leg stress peak during the take-off phase. The maximum value of the strain between the second starting point and the second ending point is taken as the first strain, and the corresponding time point is marked as the first time. When the strain reaches the first strain and firstly drops to 10% of the first strain, the corresponding time point is marked as the second time. The difference between the second time and the first time is taken as the measured deformation recovery time during the landing phase. Acquire the acceleration signal between the first end point and the second start point; perform spectral analysis on the acceleration signal to obtain a spectrum diagram; take the frequency with the largest amplitude in the spectrum diagram as the measured frequency of frame vibration during the take-off phase.

9. The method for evaluating the dynamic response of exoskeleton rigidity based on plantar excitation characteristics according to claim 1, characterized in that, The methods for assessing the rigidity of the exoskeleton include: When the peak stress deviation, vibration frequency deviation, and recovery time deviation are all within the deviation threshold, the exoskeleton's rigid dynamic response is normal. When the peak stress deviation exceeds the deviation threshold, the exoskeleton is not rigid enough. When the peak stress deviation is less than the deviation threshold, the exoskeleton is excessively rigid. When the vibration frequency deviation exceeds the deviation threshold, the exoskeleton becomes excessively rigid. When the vibration frequency deviation is less than the deviation threshold, the exoskeleton is not rigid enough. When the recovery time deviation exceeds the deviation threshold, the exoskeleton rigidity is insufficient. When the recovery time deviation is less than the deviation threshold, the exoskeleton is excessively rigid.

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