An electrically powered reciprocating foot pedal control system

Abstract

The present application relates to mode switching control technical field, specifically to a kind of electric reciprocating foot pedal control system, comprising: data acquisition unit is used to obtain the effective interactive torque of foot pedal driving motor and the instantaneous speed of foot pedal;Physiological characteristic identification unit is used to determine the initiative collaborative force degree of load and fatigue tremor degree, based on the change amount of effective interactive torque in first time window determines transient resistance resistance, in the case where transient resistance resistance meets preset spasm jamming condition generates jamming early warning signal;Torque control unit is used to dynamically adjust output torque in the case where jamming early warning signal is not generated;In the case where jamming early warning signal is generated, output torque is attenuated to zero, after meeting preset safety condition, determine torque recovery rate according to fatigue tremor degree and transient resistance resistance, based on torque recovery rate adjustment output torque.The present application improves the safety and adaptability of electric reciprocating foot pedal under complex biological load conditions.

Description

Technical Field

[0001] This invention relates to the field of mode switching control technology, specifically to an electric reciprocating foot pedal control system. Background Technology

[0002] As a periodic exercise device used for limb rehabilitation training, the core function of the electric reciprocating foot pedal is to control the foot pedal through a servo drive system to drive the human lower limbs to perform reciprocating swinging movements along a preset trajectory in order to maintain or restore joint mobility.

[0003] Currently, most electric reciprocating pedal control systems employ a proportional-integral-differential (PID) feedback control strategy based on a fixed trajectory. The system pre-sets fixed speed or sway angle parameters before operation, forcing the drive motor to run along the preset curve throughout the training process. The control parameters are not adjusted according to changes in external load conditions during use.

[0004] However, in actual rehabilitation training, the external load, namely the movement state of the lower limbs, is constantly changing, including fluctuations in muscle strength output, accumulation of physical fatigue, and sudden involuntary muscle reactions. Fixed control strategies cannot perceive and respond to these real-time changes, resulting in a low degree of matching between the equipment output and the user's actual needs, insufficient overall control adaptability, and certain safety hazards during training. Summary of the Invention

[0005] To address the technical problem of insufficient control safety of electric reciprocating foot pedals when dealing with external loads, the present invention aims to provide an electric reciprocating foot pedal control system, the specific technical solution of which is as follows:

[0006] In a first aspect, an electric reciprocating foot pedal control system is provided, comprising: a data acquisition unit for acquiring the effective interactive torque of the foot pedal drive motor and the instantaneous speed of the foot pedal, wherein the effective interactive torque is used to characterize the actual torque generated by the external load after removing the inherent torque under no-load conditions; a physiological feature recognition unit for determining the degree of active coordinated force exertion and fatigue vibration of the load based on the effective interactive torque and the instantaneous speed, and determining the transient resistance based on the change in the effective interactive torque within a first time window, and generating a jamming warning signal when the transient resistance meets a preset spasm jamming condition; and a torque control unit for dynamically adjusting the output torque based on the degree of active coordinated force exertion and fatigue vibration when no jamming warning signal is generated; attenuating the output torque to zero when a jamming warning signal is generated, and determining the torque recovery rate based on the degree of fatigue vibration and the transient resistance after meeting a preset safety condition, and adjusting the output torque based on the torque recovery rate.

[0007] In one possible design, the data acquisition unit includes a torque acquisition module, a speed determination module, and a torque compensation module. The torque acquisition module acquires the current of the drive motor through a current transformer inside the servo driver used to control the drive motor, and uses the current as the initial interactive torque. The speed determination module acquires the absolute angular position of the drive motor spindle through an absolute encoder deployed at the tail of the drive motor spindle, and determines the instantaneous speed based on the absolute angular position at adjacent sampling times. The torque compensation module queries the corresponding no-load inherent torque from a preset no-load inherent torque mapping relationship based on the direction of the absolute angular position and instantaneous speed at the current sampling time, and determines the difference between the initial interactive torque and the no-load inherent torque as the effective interactive torque.

[0008] In one possible design, the data acquisition unit also includes an unloaded calibration module; the unloaded calibration module is used to control the foot pedal to perform reciprocating motion for multiple cycles when no external load is applied to the foot pedal; the unloaded current at each angular position in different motion directions is obtained through a current transformer, and the unloaded inherent torque at each angular position in different motion directions is determined based on the unloaded current at each angular position in different motion directions, thus establishing a mapping relationship between angular position, motion direction and unloaded inherent torque.

[0009] In one possible design, the physiological characteristic recognition unit includes a force recognition module, a coordination degree determination module, and a fatigue degree determination module. The force recognition module determines the absolute value of the effective interactive torque as the forward work amount when the effective interactive torque and instantaneous velocity are in the same direction, and sets the forward work amount to zero when the effective interactive torque and instantaneous velocity are not in the same direction. The coordination degree determination module determines the degree of active coordinated force application based on the mean and standard deviation of the forward work amount at each sampling moment within a second time window. The degree of active coordinated force application characterizes the active work level and force application stability of the external load. The end time of both the second and first time windows is the current sampling moment, and the start time of the first time window is later than the start time of the second time window. The fatigue degree determination module determines the degree of fatigue tremor based on the absolute difference between the forward work amount at each sampling moment within the second time window and the historical mean of forward work amount. The fatigue tremor degree characterizes the level of muscle fatigue and involuntary shaking of the external load.

[0010] In one possible design, the physiological feature recognition unit further includes a transient resistance determination module and a stunting warning generation module; the transient resistance determination module is used to determine the transient resistance based on the change in the effective interaction torque in the first time window; the stunting warning generation module is used to determine that the preset spasm stunting condition is met and generate a stunting warning signal when the transient resistance at multiple consecutive sampling times exceeds the preset safety threshold.

[0011] In one possible design, the torque control unit includes a normal compliance control module; the normal compliance control module is used to determine the force reduction torque based on the degree of active coordinated force exertion and a first torque adjustment coefficient. The force reduction torque is used to characterize the torque value that needs to be reduced from the basic compensation torque due to the active work done by the external load. The basic compensation torque is a preset torque required to compensate for the gravitational component of the external load during the reciprocating motion of the pedal driving the external load; the fatigue compensation torque is determined based on the degree of fatigue vibration and a second torque adjustment coefficient. The fatigue compensation torque is used to characterize the additional torque value that needs to be added in addition to the basic compensation torque due to the fatigue of the external load; the output torque is determined based on the basic compensation torque, the force reduction torque, and the fatigue compensation torque.

[0012] In one possible design, the torque control unit includes an emergency retreat control module; the emergency retreat control module is used to cut off the basic compensation torque when a jamming warning signal is generated, and to take the effective interactive torque corresponding to the triggering time as the safe initial torque; to determine the dynamic attenuation rate based on the degree of active coordinated force exertion and the degree of fatigue vibration; and to attenuate the output torque from the safe initial torque based on the dynamic attenuation rate until the output torque is attenuated to zero.

[0013] In one possible design, the torque control unit further includes a silent recovery control module; the silent recovery control module is used to monitor the absolute value of the effective interactive torque after the output torque decays to zero; if the absolute value of the effective interactive torque remains below a preset safe ionization threshold for a period exceeding a preset silent waiting time, it determines that a preset safety condition is met; after the preset safety condition is met, the torque recovery rate is determined based on the maximum value of the transient resistance and the degree of fatigue vibration after the jamming warning signal is generated; the output torque is gradually increased based on the torque recovery rate until the output torque reaches the basic compensation torque, and then the system switches to the normal compliance control module.

[0014] In one possible design, the aforementioned electric reciprocating pedal control system further includes a sway amplitude control unit; the sway amplitude control unit is used to determine the target sway amplitude for the next reciprocating motion cycle based on the degree of active coordinated force and the degree of fatigue vibration determined by the physiological feature recognition unit during the reciprocating motion cycle after the pedal completes a full reciprocating motion cycle.

[0015] In one possible design, the sway amplitude control unit is specifically used to: determine the actual sway amplitude of the foot pedal during the reciprocating motion cycle based on the angular position change range of the foot pedal during the reciprocating motion cycle; determine a first amplitude adjustment amount based on the degree of active coordinated force exertion during the reciprocating motion cycle and a first amplitude adjustment coefficient; determine a second amplitude adjustment amount based on the degree of fatigue vibration during the reciprocating motion cycle and a second amplitude adjustment coefficient; determine the initial sway amplitude of the next reciprocating motion cycle based on the actual sway amplitude, the first amplitude adjustment amount, and the second amplitude adjustment amount; if the initial sway amplitude is greater than a preset maximum sway amplitude, determine the preset maximum sway amplitude as the target sway amplitude; if the initial sway amplitude is less than or equal to the preset maximum sway amplitude, determine the initial sway amplitude as the target sway amplitude.

[0016] The present invention has the following beneficial effects:

[0017] In the electric reciprocating foot pedal control system provided by this invention, the data acquisition unit compensates for the initial interactive torque using no-load calibration to obtain the effective interactive torque, eliminating the interference of the equipment's own resistance on load state identification; the physiological feature identification unit extracts the forward work based on the directional relationship between the effective interactive torque and the instantaneous velocity, and quantifies the degree of active coordinated force exertion and the degree of fatigue vibration by using the mean, standard deviation and deviation from the historical mean within the statistical window, respectively; at the same time, it calculates the transient resistance using the short-time window difference and generates a jamming warning signal by combining continuous multi-cycle criteria, thereby reliably distinguishing between the active force exertion, fatigue vibration and sudden muscle spasm of the load under the premise of eliminating the influence of gradual changes in gravity; the torque control unit uses the basic compensation torque as a benchmark under normal conditions, reduces the output torque according to the degree of active coordinated force exertion to relinquish the dominant position, and increases the output torque according to the degree of fatigue vibration to provide fallback protection; when jamming is detected, the output torque is attenuated to zero, and after confirming that the load is continuously relaxed, the recovery rate is determined based on the degree of fatigue vibration and the peak value of historical transient resistance, and the auxiliary torque is gradually rebuilt. Therefore, by deeply coupling the torque assistance, yielding and recovery process with real-time physiological characteristics, the problem of traditional fixed threshold control being unable to distinguish between active resistance and spasm, and being prone to accidental shutdown or forced pulling is overcome, thus comprehensively improving the safety and adaptability of electric reciprocating pedals under complex biological load conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an electric reciprocating foot pedal control system provided in one embodiment of the present invention. Detailed Implementation

[0019] The specific solution of an electric reciprocating foot pedal control system provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Please see Figure 1 It shows a schematic diagram of the structure of an electric reciprocating foot pedal control system according to an embodiment of the present invention, as follows: Figure 1 As shown, the electric reciprocating foot pedal control system 10 includes a data acquisition unit 11, a physiological feature recognition unit 12, and a torque control unit 13.

[0021] The data acquisition unit 11 is used to acquire the effective interactive torque of the foot pedal drive motor and the instantaneous speed of the foot pedal. The effective interactive torque is used to characterize the actual torque generated by the external load after removing the no-load inherent torque.

[0022] As one possible implementation, the data acquisition unit 11 includes a torque acquisition module, a speed determination module, a torque compensation module, and an unloaded calibration module.

[0023] The torque acquisition module obtains the current of the drive motor through a current transformer inside the servo driver used to control the drive motor, at a preset sampling period. In this embodiment, the preset sampling period can be 1 millisecond. During the movement of the foot pedal, there is a definite correspondence between the winding current and the output torque of the drive motor; the greater the total mechanical resistance borne by the motor, the greater the current required to drive its rotation. Based on this physical characteristic, the torque acquisition module directly uses the current obtained from each sampling as the initial interactive torque. This initial interactive torque includes the torque component applied by the external load and the unloaded inherent torque of the device's own transmission mechanism.

[0024] Simultaneously, the speed determination module acquires the absolute angular position of the drive motor spindle using an absolute encoder deployed at the tail of the drive motor spindle at the same preset sampling period. The absolute encoder outputs an absolute position value relative to a fixed zero position, rather than a relative change. To determine the direction and speed of the pedal movement in real time, the speed determination module performs discrete difference calculations based on the absolute angular positions of adjacent sampling moments. That is, it subtracts the absolute angular position of the previous sampling moment from the current sampling moment's absolute angular position, and the resulting difference is the instantaneous speed corresponding to the current sampling moment. The sign of the instantaneous speed is used to characterize the direction of the pedal movement. When the instantaneous speed is positive, it indicates that the pedal is in the downward pressing phase; when the instantaneous speed is negative, it indicates that the pedal is in the upward pulling phase.

[0025] It should be noted that since the initial interaction torque includes the unloaded inherent torque of the transmission mechanism, directly using it as a measure of the external load torque will lead to deviations in the calculation results of the subsequent physiological feature recognition stage. To solve this problem, the data acquisition unit adopts a combination of unloaded calibration and online compensation to remove the unloaded inherent torque from the initial interaction torque.

[0026] In some embodiments, the no-load calibration module is used to establish a mapping relationship between the angular position and direction of movement and the no-load inherent torque when the pedal is not under external load, providing reference data for the torque compensation module. The no-load inherent torque characterizes the torque required by the pedal transmission mechanism to overcome inherent resistances such as gear meshing friction and bearing rotation friction at different angular positions and directions of movement. Since the dry friction of the transmission mechanism is always opposite to the direction of movement, and factors such as gear backlash may cause differences in the upward and downward contact surfaces, the no-load inherent torque varies when the pedal is in different directions of movement at the same angular position. Therefore, no-load calibration requires establishing a two-dimensional mapping relationship using both angular position and direction of movement as index dimensions.

[0027] The no-load calibration module controls the foot pedal to perform multiple cycles of standard reciprocating motion, typically 3 to 5 complete reciprocating cycles, to eliminate random fluctuations in a single motion and improve the reliability of the calibration data. During calibration, the current transformer in the torque acquisition module synchronously collects the current value at each absolute angular position in each motion cycle. Simultaneously, the direction of the instantaneous velocity output by the module is determined based on the velocity, and the collected current values ​​are categorized and recorded according to the absolute angular position and the direction of motion. For example, a positive instantaneous velocity corresponds to a downward motion phase, and a negative instantaneous velocity corresponds to an upward motion phase. For the same absolute angular position and the same polarity of motion direction, the average of the current values ​​collected over multiple reciprocating motion cycles is taken. This average is used as the no-load inherent torque corresponding to that absolute angular position in that motion direction, thus constructing a two-dimensional no-load inherent torque mapping relationship with the absolute angular position and instantaneous velocity direction as a joint index, for real-time retrieval during load operation. The method of averaging multi-cycle data effectively eliminates the interference of random fluctuations in a single motion, improving the reliability of the calibration data.

[0028] During operation under load, the torque compensation module, based on the absolute angular position and instantaneous velocity direction at the current sampling moment, queries the two-dimensional unloaded inherent torque mapping relationship constructed by the unloaded calibration module to find the unloaded inherent torque that matches the current angular position and motion direction. The initial interactive torque is then subtracted from this unloaded inherent torque, and the resulting difference is the effective interactive torque. The effective interactive torque characterizes the actual torque generated by the external load at the current angular position and current motion direction after removing the unloaded inherent torque.

[0029] The physiological feature recognition unit 12 is used to determine the degree of active coordinated force exertion and fatigue vibration of the load based on the effective interactive torque and instantaneous velocity, and to determine the transient resistance based on the change of the effective interactive torque within the first time window. When the transient resistance meets the preset spasm and stunting conditions, a stunting warning signal is generated.

[0030] As one possible implementation, the physiological feature recognition unit 12 includes a force recognition module, a coordination degree determination module, a fatigue degree determination module, a transient resistance determination module, and a jamming warning generation module.

[0031] The force recognition module first determines the direction of the external load to separate the active work component consistent with the direction of motion from the effective interactive torque, eliminating interference from reverse resistance and passive loading. During actual operation, the external load may apply force to the foot pedal in different directions. When the direction of the load's force is the same as the instantaneous direction of the foot pedal's motion, it indicates that the load is actively participating in the motion; otherwise, it indicates that the load is in a passive loading or reverse resistance state.

[0032] In some embodiments, to accurately determine the active force exertion intention of the external load, the force identification module determines the sign relationship between the effective interactive torque and the instantaneous velocity to ensure consistency between the direction of the effective interactive torque and the direction of the instantaneous velocity. Specifically, when the product of the two is greater than zero, it indicates that the direction of the effective interactive torque is consistent with the direction of the pedal movement; for example, when the pedal moves downwards, the external load also actively pushes downwards. In this case, the absolute value of the effective interactive torque is determined as the forward work. When the product of the two is less than or equal to zero, it indicates that the external load is in a reverse physical resistance or is merely passively placing its limbs on the pedal. In this case, the forward work is set to zero. By filtering based on the effective interactive torque and the directionality of the movement, interference from passive weight and reverse resistance torque is effectively eliminated, and the forward work only reflects the true intention of the external load to actively perform work.

[0033] After determining the forward work done at each sampling moment, the coordination level determination module is used to quantify the active coordinated force exertion level of the external load. During rehabilitation training, the force exertion state of the external load, i.e., the lower limbs, is constantly changing, and there is almost no absolutely constant force exertion level.

[0034] In some embodiments, to accurately assess whether the external load is actively and collaboratively performing work, it is necessary to statistically analyze the forward work volume within a certain time range. The level of force exertion by the external load is reflected not only in the magnitude of the forward work volume but also in the stability of the force exertion process: continuous and stable active force exertion indicates that the load is in a good collaborative state, while unstable force exertion with fluctuating magnitudes indicates that the load's collaborative ability is weak. Therefore, it is necessary to consider both the mean and standard deviation of the forward work volume to comprehensively evaluate the degree of collaborative force exertion. The degree of active collaborative force exertion is used to characterize the level of active work exertion and the stability of force exertion of the external load. Within the second time window, the collaboration degree determination module calculates the mean and standard deviation of the forward work volume at each sampling moment to determine the degree of active collaborative force exertion. The end time of the second time window is the current sampling moment, and the duration of the second time window can be 1000 milliseconds for example, that is, it includes 1000 sampling points under the condition of a preset sampling period of 1 millisecond.

[0035] Optionally, the calculation formula for determining the degree of proactive coordinated effort is as follows:

[0036]

[0037] In the formula, Indicates the sampling time The corresponding level of proactive and coordinated efforts; Indicates the second time window The mean of the forward work done at each sampling time point , The larger the value, the higher the level of active work done by the external load. This represents the total number of discrete sampling points included within the second time window; for example, a value of 1000. Indicates the second time window The amount of work done in the forward direction at each sampling time; Indicates the second time window The standard deviation of the forward work done at each sampling moment. The smaller the value, the more stable the external load is; the larger the value, the more violent the fluctuation in the force. This is a preset bias constant used to prevent calculation anomalies caused by a denominator of zero. Its value can be taken with reference to the normal range of variation of the standard deviation of forward work. For example, a value of 1 can be taken. This indicates that normalization will be performed. The calculation results are mapped to a range of 0 to 1. For example, a maximum-minimum normalization method can be used. During equipment commissioning, the maximum and minimum values ​​of the above calculation results are obtained through standard load testing. When the calculated result is greater than the maximum value obtained through standard load testing, the normalized result is clamped to 1; when the calculated result is less than the minimum value obtained through standard load testing, the normalized result is clamped to 0. In the above calculation formula, the higher the mean and the smaller the standard deviation of the forward work, the better. The larger the value, the higher the level of active work done by the external load and the more stable the force exerted.

[0038] The fatigue level determination module is used to quantify the level of muscle fatigue and involuntary tremors under external load. When the external load, i.e., the strength of the lower limbs decreases and the nerve's control over the muscles weakens, it is often accompanied by high-frequency involuntary muscle tremors, causing the actual instantaneous output force to deviate sharply from the historical average force level. The greater the deviation, the higher the degree of fatigue under external load.

[0039] In some embodiments, to quantify the degree of deviation, the fatigue degree determination module determines the degree of fatigue tremor based on the absolute difference between the forward work done at each sampling moment and the historical average forward work done within a second time window. The degree of fatigue tremor is used to characterize the level of muscle fatigue and involuntary shaking under external load.

[0040] Optionally, the formula for calculating the degree of fatigue vibration is as follows:

[0041]

[0042] In the formula, Indicates the sampling time The corresponding degree of fatigue vibration; This represents the total number of discrete sampling points contained within the second time window; Indicates the second time window The amount of work done in the forward direction at each sampling time; This represents the average forward work done in history, which is the average forward work done within a preset historical time range. For example, it can be taken as the average forward work done at all sampling moments since the start of the program. This indicates the calculation of the second time window. The absolute difference between the forward work done at each sampling time and the historical average forward work; This indicates that normalization will be performed. The calculation results are mapped to 0 to 1. For example, a maximum-minimum normalization method can be used. During the equipment commissioning phase, the maximum and minimum values ​​of the above calculation results are obtained through standard load testing. When the normalized value of the above calculation result is greater than the maximum value obtained through standard load testing, the normalization result is clamped to 1; when the normalized value of the above calculation result is less than the minimum value obtained through standard load testing, the normalization result is clamped to 0. If the external load is applied smoothly and continuously, the deviation between the forward work done at each sampling time and the historical average is minimal. Approaching zero; if the external load experiences high-frequency muscle tremors and unstable force exertion, the forward work done at each sampling time will deviate drastically from the historical average. It showed a significant increase.

[0043] After assessing the degree of active coordinated force exertion and fatigue tremor, the transient resistance determination module is used to detect possible sudden muscle spasms.

[0044] It should be noted that muscle spasms are fundamentally different from normal exertion and changes in gravity during rehabilitation training: spasms are explosive muscle stiffness that occurs within an extremely short time, i.e., tens of milliseconds, while gravity changes slowly with the circular motion of the pedal. Because the resistance change caused by gravity is low-frequency and slow, the slow-changing interference is largely canceled out by the difference calculation within a very short time window, resulting in a small calculated change; however, the sudden change in torque caused by spasms is a huge jump in a very short time, resulting in a significantly larger calculated change.

[0045] In some embodiments, the transient resistance determination module determines the change in effective interaction torque within a first time window, i.e., the absolute difference between the effective interaction torque at the current sampling moment and the effective interaction torque at the beginning of the first time window, and determines the calculated absolute difference as the transient resistance at the current sampling moment. A larger transient resistance value indicates a greater degree of explosive torque change in the external load within a short time window, and a higher likelihood of muscle spasm. The end of the first time window is the current sampling moment, and the duration of the first time window is shorter than the duration of the second time window; for example, it can be 50 milliseconds, meaning it includes 50 sampling points under a preset sampling period of 1 millisecond.

[0046] Finally, the stunting warning generation module is used to generate a stunting warning signal when the preset stunting conditions are met.

[0047] In some embodiments, considering that sensor noise or occasional transient interference may cause transient resistance to occasionally exceed a preset safety threshold, directly triggering an early warning based on this would result in frequent false alarms. Therefore, the jamming early warning generation module introduces a continuity criterion in the time dimension. The jamming early warning generation module maintains an abnormal accumulation counter. At each sampling moment, if the transient resistance exceeds the preset safety threshold, the abnormal accumulation counter increments; once the transient resistance falls below the preset safety threshold, the abnormal accumulation counter is immediately reset to zero. Only when the count value of the abnormal accumulation counter continuously increases over multiple consecutive control cycles and reaches a preset number of consecutive triggers is it determined that the preset spasm jamming condition is met, and a jamming early warning signal is generated.

[0048] The preset safety threshold is determined based on the statistical distribution of transient resistance during normal operation. For example, it can be set to 1.5 times the historical average of transient resistance recorded during normal load operation. The preset number of consecutive triggers can be 3, that is, if transient resistance exceeds the standard for 3 consecutive sampling cycles (equivalent to 3 milliseconds when the sampling cycle is 1 millisecond), then it is confirmed that a real jam has occurred and a jam warning signal is generated.

[0049] The torque control unit 13 is used to dynamically adjust the output torque according to the degree of active coordinated force and the degree of fatigue vibration when no jamming warning signal is generated; when a jamming warning signal is generated, the output torque is attenuated to zero, and after the preset safety conditions are met, the torque recovery rate is determined according to the degree of fatigue vibration and transient resistance, and the output torque is adjusted based on the torque recovery rate.

[0050] As one possible implementation, the torque control unit 13 is used to switch between three control modes based on the active coordinated force application level, fatigue vibration level, transient resistance, and jamming warning signal output by the physiological characteristic identification unit, and to determine the output torque in real time to drive the foot pedal movement. The torque control unit includes a normal compliance control module, an emergency yielding control module, and a silent recovery control module.

[0051] The torque control unit 13 switches between the three control modes according to the following logic: when no jamming warning signal is generated, the torque control unit 13 adjusts the output torque through the normal compliance control module; when a jamming warning signal is generated, the torque control unit 13 switches to the emergency yield control module; after the emergency yield control module attenuates the output torque to zero, the torque control unit 13 switches to the silent recovery control module; when the silent recovery control module restores the output torque to a value greater than or equal to the basic compensation torque, the torque control unit 13 switches back to the normal compliance control module.

[0052] In some embodiments, the normal compliance control module is used to dynamically adjust the output torque based on the degree of active coordinated force exertion and the degree of fatigue vibration when no jamming warning signal is generated, so as to intelligently comply with the dynamic intentions of the external load in a safe and coordinated state. In the normal compliance control mode, when the external load actively and intentionally exerts force, the module proportionally reduces its own intervention torque to relinquish control; when the external load exhibits fatigue vibration, the module increases the auxiliary support torque for backup protection.

[0053] To implement this control logic, the normal compliance control module maintains a preset base compensation torque. This base compensation torque is the preset torque required to compensate for the gravitational component of the external load during the reciprocating motion of the foot pedal. Its value can be determined during equipment debugging based on the weight of the external load and the kinematic parameters of the foot pedal mechanism. For example, it can be 1 to 1.2 times the maximum gravitational component of the external load weight in the foot pedal's motion plane. Based on this, the normal compliance control module determines the force reduction torque according to the degree of active coordinated force exertion and the first torque adjustment coefficient. This force reduction torque characterizes the torque value that needs to be reduced from the base compensation torque due to the active work done by the external load. It also determines the fatigue compensation torque according to the degree of fatigue vibration and the second torque adjustment coefficient. This fatigue compensation torque characterizes the additional torque value that needs to be added beyond the base compensation torque due to the fatigue of the external load. Finally, the output torque is jointly determined by the base compensation torque, the force reduction torque, and the fatigue compensation torque.

[0054] Optionally, the normal compliance control module determines the calculation formula for the output torque as follows:

[0055]

[0056] In the formula, Indicates the sampling time under normal compliance control mode. The corresponding output torque is sent to the servo driver; Indicates the basic compensation torque; Indicates the sampling time The corresponding degree of proactive collaborative effort ranges from 0 to 1. Indicates the sampling time The corresponding fatigue vibration level, after normalization, also ranges from 0 to 1. This represents the first torque adjustment coefficient, used to determine the upper limit of the reduction in base torque when the system is actively exerting force at full load. For example, if it is set to reduce the base compensation torque by a maximum of 30%, then... The value is 0.3; This represents the second torque adjustment coefficient, used to determine the upper limit of the additional auxiliary torque that the system can add under extreme fatigue vibration. For example, if it is set that a maximum of 80% of the basic compensation torque can be added as fatigue compensation, then... The value is 0.8.

[0057] in, To reduce torque during power generation, This indicates the proportion of the base compensation torque that needs to be reduced due to the active work done by the external load. The larger the value, the larger the ratio, and the smaller the machine's output torque, meaning the machine relinquishes more control to the external load. For fatigue compensation torque, This indicates the percentage of additional torque required beyond the basic compensation torque due to fatigue caused by external loads. The larger the value, the greater the ratio, and the greater the machine's output torque, meaning the machine provides more auxiliary support.

[0058] The emergency retreat control module is used to quickly reduce the output torque to zero when a jamming warning signal is generated, in order to prevent the machine from continuing to apply torque when the external load causes muscle spasms and thus causing secondary damage.

[0059] In some embodiments, when the emergency retreat control module receives a jamming warning signal, it first cuts off the basic compensation torque and uses the effective interactive torque corresponding to the trigger moment as the safe initial torque. The safe initial torque is used to characterize the actual torque level borne by the external load at the moment of jamming. This value is locked as the starting point of the attenuation process to ensure that the torque attenuation starts from the actual force state rather than from the control command, avoiding inaccurate attenuation start due to the deviation between the control command and the actual force.

[0060] After determining the safe initial torque, the emergency retreat control module determines the dynamic decay rate based on the degree of active coordinated force exertion and the degree of fatigue vibration. The dynamic decay rate characterizes the rate at which the torque decays from the safe initial torque. Determining the dynamic decay rate requires comprehensive consideration of the real-time physiological state of the external load: when the external load is in a state of high fatigue, i.e., the muscles are on the verge of weakness, the decay rate should be increased to unload stress more quickly and prevent tendon damage; when the external load is in a state of high-intensity coordinated force exertion before jamming, if the machine resistance disappears instantaneously, the enormous inertia of the external load itself can easily lead to joint overextension, therefore the decay rate should be appropriately reduced to buffer the inertial impact.

[0061] Optionally, the formula for calculating the dynamic decay rate is as follows:

[0062]

[0063] In the formula, This indicates the dynamic attenuation rate of the emergency retreat control module after receiving a jamming warning signal and entering the emergency retreat control mode. This indicates the preset baseline attenuation rate, which can be set to 5% of the rated output torque per millisecond. The rated output torque is the maximum torque value that the drive motor is allowed to output under continuous operation, and its value is determined according to the specifications of the drive motor. Indicates the sampling time The corresponding degree of fatigue vibration; Indicates the sampling time The corresponding degree of proactive and coordinated effort. In this formula, The larger the value, the greater the dynamic decay rate and the faster the torque unloading. The larger the value, the smaller the dynamic decay rate and the slower the torque unloading, thus buffering the work inertia of the external load.

[0064] Optionally, to prevent the dynamic attenuation rate from exceeding the safe range, the determined dynamic attenuation rate is limited within a preset attenuation rate safety range. The preset attenuation rate safety range is defined by a preset minimum attenuation rate and a preset maximum attenuation rate. The preset minimum attenuation rate can be, for example, 20% of the preset baseline attenuation rate, and the preset maximum attenuation rate can be, for example, three times the preset baseline attenuation rate. When the calculated dynamic attenuation rate is less than the preset minimum attenuation rate, the dynamic attenuation rate is clamped to the preset minimum attenuation rate; when the calculated dynamic attenuation rate is greater than the preset maximum attenuation rate, the dynamic attenuation rate is clamped to the preset maximum attenuation rate.

[0065] After determining the dynamic attenuation rate, the emergency retreat control module further attenuates the output torque starting from the safe initial torque. The attenuation process can be expressed as follows: In the formula, Indicates the sampling time in emergency retreat control mode. The corresponding output torque is sent to the servo driver; This represents the initial safety torque locked based on the effective interactive torque corresponding to the triggering time; This indicates the cumulative time elapsed since entering emergency retreat control mode; The dynamic decay rate is defined as follows: the output torque starts from a safe initial torque and decreases linearly over time; the rate of decrease is the dynamic decay rate. During the decay process, the calculated value of the output torque is monitored in real time. Once this calculated value is less than or equal to zero, the output torque is clamped to zero, triggering a switch from emergency retreat control mode to silent recovery control mode.

[0066] The silent recovery control module is used to gradually restore the output torque at a smooth rate after the output torque has decayed to zero, provided that the external load spasm has been completely relieved, to prevent abrupt torque changes from causing a startle reflex in the external load.

[0067] In some embodiments, after the torque control unit switches to this module, the silent recovery control module maintains zero torque output and continuously monitors the absolute value of the effective interactive torque. When the absolute value of the effective interactive torque remains below a preset safe ionization threshold for a period exceeding a preset silent waiting time, the silent recovery control module determines that the preset safety condition is met, i.e., the spasm of the external load has been completely relieved and the physiological state has been completely relaxed. The preset safe ionization threshold is used to define the range within which the absolute value of the effective interactive torque can be considered as the external load being in a stress-free relaxation state; its value is set to 5% of the rated output torque. The preset silent waiting time is used to define how long the low-stress state must last before it can be determined that the spasm has been completely relieved; its value needs to be determined by comprehensively considering the typical recovery time after the external load spasms, and can be exemplarily set to 2000 milliseconds.

[0068] After the preset safety conditions are met, the silent recovery control module gradually increases the output torque according to the torque recovery rate. Specifically, the larger the peak value of the transient resistance in the previous emergency retreat event, the more severe the spasm that just occurred. In this case, the torque recovery rate should be smaller to recover the torque in a smoother manner and avoid stimulating the external load to spasm again. Similarly, the higher the current fatigue vibration level of the external load, the more vulnerable the external load is in a relatively fragile physiological state. The torque recovery rate should also be smaller in this case.

[0069] Optionally, the formula for calculating the torque recovery rate is as follows:

[0070]

[0071] In the formula, This indicates the torque recovery rate determined by the silent recovery control module after the preset safety conditions are met; This indicates the preset standard recovery slope, which can be set to 1% of the rated output torque per millisecond for example. This represents the maximum value of the transient resistance recorded during the operation of the emergency retreat control module; Indicates to Perform normalization processing, for example, Divide it by the preset maximum design tolerance resistance constant and map it to a proportionality coefficient between 0 and 1. The preset maximum design tolerance resistance constant is the maximum resistance torque that the equipment structure design can withstand. Its value is determined according to the mechanical structure strength calibration of the equipment. Indicates the sampling time The corresponding degree of fatigue tremor. The more intense the spasm resistance ( (Larger) or the more severe the current fatigue tremor ( When the denominator is large, the torque recovery rate is smaller, and the output torque recovery is more stable and cautious.

[0072] After determining the torque recovery rate, the silent recovery control module gradually increases the output torque. The recovery process of the output torque can be expressed as follows: In the formula, Indicates the sampling time in silent recovery control mode. The corresponding output torque is sent to the servo driver; This indicates the recovery duration that begins after entering the silent recovery control module and meeting the preset safety conditions; This indicates the torque recovery rate. The silent recovery control module monitors the output torque in real time. When the output torque recovers to a level greater than or equal to the basic compensation torque, it determines that the output torque has recovered to the normal level, triggers the torque control unit 13 to switch back to the normal compliance control module, exits the silent recovery control mode, and re-enters the normal compliance control module's operating logic. The three control modes of the torque control unit 13 have thus completed a complete cycle of switching.

[0073] In one design, the electric reciprocating foot pedal control system 10 also includes a swing amplitude control unit. This control unit dynamically plans the target swing amplitude for the next movement cycle after each complete reciprocating cycle of the foot pedal, based on the degree of active coordinated force exertion and fatigue vibration of the external load during that cycle. During rehabilitation training, the joint mobility and muscle state under external load are not constant. If the swing amplitude of the foot pedal remains constant, it will not match the actual physiological state of gradual recovery or fatigue under load. By dynamically adjusting the swing amplitude within safe limits, the training intensity can be adapted to the actual physical condition of the load, achieving gradual expansion of joint mobility or protective contraction.

[0074] The sway amplitude control unit triggers an amplitude update after each complete reciprocating motion cycle of the foot pedal. The reciprocating motion cycle is determined by the foot pedal starting from a preset starting angle position, experiencing one complete downward stroke and one complete pull-back stroke, and then returning to the preset starting angle position. For example, the preset starting angle position can be the midpoint of the foot pedal's range of motion.

[0075] After each reciprocating motion cycle, the sway amplitude control unit first determines the actual sway amplitude of the reciprocating motion cycle. This actual sway amplitude reflects the angular range of the pedal during the just-completed motion cycle. The sway amplitude control unit determines the actual sway amplitude based on the range of angular position changes of the pedal during the reciprocating motion cycle. Specifically, it records the maximum and minimum angular positions reached by the pedal during the reciprocating motion cycle, and determines the absolute value of the difference between the maximum and minimum angular positions as the actual sway amplitude.

[0076]

[0077] In the formula, Indicates the next cycle of reciprocating motion, i.e., the th cycle. The initial sway amplitude of one reciprocating motion cycle; This indicates the period of reciprocating motion, i.e., the th... The actual swing amplitude of one reciprocating motion cycle; Indicates the first The average value of the degree of active coordinated force at each sampling moment within a reciprocating motion cycle, with a value ranging from 0 to 1. Indicates the first The average value of the fatigue vibration degree at each sampling time within a reciprocating motion cycle, which also ranges from 0 to 1. This represents the first amplitude adjustment coefficient, used to determine the maximum amplitude adjustment ratio that can be extended in a single reciprocating motion cycle when the load is fully applied and the force is actively exerted. For example, A possible value is 0.1, which means that when the load is fully applied and the force is actively exerted, the swing amplitude of the next reciprocating motion cycle can be extended by up to 10% compared to the current reciprocating motion cycle; This represents the second amplitude adjustment coefficient, used to determine the maximum amplitude adjustment ratio that can be contracted in a single reciprocating motion cycle under extreme fatigue vibration under load. For example... The value can be 0.1, which means that when the load is extremely fatigued and vibrates, the swing amplitude of the next reciprocating motion cycle can be reduced by up to 10% compared with the current reciprocating motion cycle.

[0078] in, This is the first adjustment amount. This represents the proportion that needs to be expanded outward from the actual sway amplitude of the current reciprocating motion cycle due to the active force exerted by the external load. The larger the value, the larger the proportion, and the more the initial swing amplitude of the next reciprocating motion cycle expands relative to the current reciprocating motion cycle. That is, the range of motion of the joint is automatically accumulated when the load is actively exerted. This is the second adjustment amount. This indicates the proportion that needs to contract inward from the actual swaying amplitude of the current reciprocating motion cycle due to external load fatigue. The larger the value, the greater the proportion, and the more the initial sway amplitude of the next reciprocating motion cycle contracts relative to the current reciprocating motion cycle. In other words, the system automatically reduces the range of motion of the joints to provide protection when fatigue vibration occurs under load.

[0079] After calculating the initial swing amplitude, the swing amplitude control unit performs a safety limit process on the initial swing amplitude.

[0080] Optionally, the swing amplitude control unit compares the initial swing amplitude with the preset maximum swing amplitude. If the initial swing amplitude is greater than the preset maximum swing amplitude, the preset maximum swing amplitude is used as the target swing amplitude; if the initial swing amplitude is less than or equal to the preset maximum swing amplitude, the initial swing amplitude is used as the target swing amplitude. The preset maximum swing amplitude is determined comprehensively based on the physical limits of the device's mechanical structure and the safe range of motion of the human joint. For example, it can be set to 20 degrees for ankle rehabilitation scenarios and 60 degrees for knee rehabilitation scenarios.

[0081] Furthermore, to prevent abrupt changes in swing amplitude between adjacent reciprocating motion cycles when the external load condition fluctuates drastically, the swing amplitude control unit can also impose a preset maximum single-cycle variation limit on the swing amplitude change between adjacent reciprocating motion cycles. The preset maximum single-cycle variation is used to define the maximum allowable difference between the target swing amplitudes of two adjacent reciprocating motion cycles, and its value is determined based on the calibration of the safe joint range of motion change rate under the external load; for example, it can be 3 degrees. Specifically, before outputting the target swing amplitude, the swing amplitude control unit compares the calculated target swing amplitude with the actual swing amplitude of the current reciprocating motion cycle: when the absolute value of the difference between the target swing amplitude and the actual swing amplitude of the current motion cycle is less than or equal to the preset maximum change in a single cycle, the calculated target swing amplitude is directly output; when the target swing amplitude is greater than the actual swing amplitude of the current motion cycle and the difference exceeds the preset maximum change in a single cycle, the target swing amplitude is adjusted to the actual swing amplitude of the current motion cycle plus the preset maximum change in a single cycle; when the target swing amplitude is less than the actual swing amplitude of the current motion cycle and the difference exceeds the preset maximum change in a single cycle, the target swing amplitude is adjusted to the actual swing amplitude of the current motion cycle minus the preset maximum change in a single cycle.

[0082] Understandably, in the electric reciprocating foot pedal control system provided in this embodiment of the invention, the data acquisition unit compensates for the initial interactive torque using no-load calibration to obtain the effective interactive torque, eliminating the interference of the equipment's own resistance on load state identification; the physiological feature identification unit extracts the forward work based on the directional relationship between the effective interactive torque and the instantaneous velocity, and quantifies the degree of active coordinated force exertion and the degree of fatigue vibration by using the mean, standard deviation and deviation from the historical mean within the statistical window, respectively; at the same time, it calculates the transient resistance using the short-time window difference and generates a jamming warning signal by combining continuous multi-cycle criteria, thereby reliably distinguishing the active force exertion, fatigue vibration and sudden muscle spasm of the load under the premise of eliminating the influence of gradual changes in gravity; the torque control unit uses the basic compensation torque as a benchmark under normal conditions, reduces the output torque according to the degree of active coordinated force exertion to relinquish the dominant position, and increases the output torque according to the degree of fatigue vibration to provide a safety net; when jamming is detected, the output torque is attenuated to zero, and after confirming that the load is continuously relaxed, the recovery rate is determined based on the degree of fatigue vibration and the peak value of historical transient resistance, and the auxiliary torque is gradually rebuilt. Therefore, by deeply coupling the torque assistance, yielding and recovery process with real-time physiological characteristics, the problem of traditional fixed threshold control being unable to distinguish between active resistance and spasm, and being prone to accidental shutdown or forced pulling is overcome, thus comprehensively improving the safety and adaptability of electric reciprocating pedals under complex biological load conditions.

Claims

1. An electric reciprocating foot pedal control system, characterized in that, include: The data acquisition unit is used to acquire the effective interactive torque of the foot pedal drive motor and the instantaneous speed of the foot pedal. The effective interactive torque is used to characterize the actual torque generated by the external load after removing the unloaded inherent torque. The physiological feature recognition unit is used to determine the degree of active coordinated force exertion and fatigue vibration of the load based on the effective interactive torque and the instantaneous velocity, and to determine the transient resistance based on the change of the effective interactive torque within the first time window, and to generate a stagnation warning signal when the transient resistance meets the preset spasm stagnation conditions. A torque control unit is used to dynamically adjust the output torque based on the degree of active coordinated force exertion and the degree of fatigue vibration when the jamming warning signal is not generated. When the jamming warning signal is generated, the output torque is attenuated to zero, and after the preset safety conditions are met, the torque recovery rate is determined according to the degree of fatigue vibration and the transient resistance, and the output torque is adjusted based on the torque recovery rate.

2. The electric reciprocating foot pedal control system according to claim 1, characterized in that, The data acquisition unit includes a torque acquisition module, a velocity determination module, and a torque compensation module; The torque acquisition module is used to acquire the current of the drive motor through the current transformer inside the servo driver used to control the drive motor, and use the current as the initial interaction torque. The speed determination module is used to obtain the absolute angular position of the drive motor spindle by an absolute encoder deployed at the tail of the drive motor spindle, and to determine the instantaneous speed based on the absolute angular position at adjacent sampling times. The torque compensation module is used to query the corresponding unloaded inherent torque from the preset unloaded inherent torque mapping relationship based on the absolute angle position and instantaneous velocity direction at the current sampling time, and determine the difference between the initial interaction torque and the unloaded inherent torque as the effective interaction torque.

3. The electric reciprocating foot pedal control system according to claim 2, characterized in that, The data acquisition unit also includes an idle calibration module; The no-load calibration module is used to control the foot pedal to perform multiple cycles of reciprocating motion when no external load is applied to the foot pedal. The no-load current at each angular position under different motion directions is obtained through the current transformer, and the no-load inherent torque at each angular position under different motion directions is determined based on the no-load current at each angular position under different motion directions, thus establishing a mapping relationship between angular position, motion direction and no-load inherent torque.

4. The electric reciprocating foot pedal control system according to claim 1, characterized in that, The physiological feature recognition unit includes a force recognition module, a coordination degree determination module, and a fatigue degree determination module; The force recognition module is used to determine the absolute value of the effective interactive torque as the forward work amount when the direction of the effective interactive torque is consistent with the direction of the instantaneous velocity, and to set the forward work amount to zero when the direction of the effective interactive torque is inconsistent with the direction of the instantaneous velocity. The coordination degree determination module is used to determine the degree of active coordination based on the mean and standard deviation of the forward work done at each sampling time within the second time window. The degree of active coordination is used to characterize the active work level and power stability of the external load. The end time of the second time window and the end time of the first time window are both the current sampling time, and the start time of the first time window is later than the start time of the second time window. The fatigue degree determination module is used to determine the fatigue tremor degree based on the absolute difference between the forward work done at each sampling moment within the second time window and the historical average forward work done. The fatigue tremor degree is used to characterize the level of muscle fatigue and involuntary shaking under external load.

5. The electric reciprocating foot pedal control system according to claim 4, characterized in that, The physiological feature recognition unit also includes a transient resistance determination module and a jamming warning generation module; The transient resistance determination module is used to determine the transient resistance based on the change in the effective interaction torque in the first time window. The stagnation warning generation module is used to determine that the preset spasm stagnation condition is met and generate the stagnation warning signal when the transient resistance at multiple consecutive sampling times exceeds the preset safety threshold.

6. The electric reciprocating foot pedal control system according to claim 1, characterized in that, The torque control unit includes a normal compliance control module; The normal compliance control module is used to determine the force reduction torque based on the degree of active coordinated force exertion and the first torque adjustment coefficient. The force reduction torque is used to characterize the torque value that needs to be reduced from the basic compensation torque due to the active work done by the external load. The basic compensation torque is the preset torque required to compensate for the gravitational component of the external load during the reciprocating motion of the foot pedal driving the external load. The fatigue compensation torque is determined based on the fatigue vibration degree and the second torque adjustment coefficient. The fatigue compensation torque is used to characterize the additional torque value that needs to be added in addition to the basic compensation torque due to fatigue caused by external load. The output torque is determined based on the basic compensation torque, the force reduction torque, and the fatigue compensation torque.

7. The electric reciprocating foot pedal control system according to claim 6, characterized in that, The torque control unit includes an emergency yielding control module; The emergency retreat control module is used to cut off the basic compensation torque when the jamming warning signal is generated, and to take the effective interactive torque corresponding to the triggering time as the safety initial torque. The dynamic attenuation rate is determined based on the degree of active coordinated force exertion and the degree of fatigue vibration. Based on the dynamic decay rate, the output torque is decayed from the initial safe torque until the output torque decays to zero.

8. The electric reciprocating foot pedal control system according to claim 7, characterized in that, The torque control unit also includes a silent recovery control module; The silent recovery control module is used to monitor the absolute value of the effective interactive torque after the output torque decays to zero. If the absolute value of the effective interaction torque remains below the preset safe ionization threshold for a period exceeding the preset silent waiting time, the preset safety condition is determined to be met. After the preset safety conditions are met, the torque recovery rate is determined based on the maximum value of the transient resistance after the jamming warning signal is generated and the degree of fatigue vibration. The output torque is gradually increased based on the torque recovery rate until the output torque reaches the basic compensation torque, and then the system switches to the normal compliance control module.

9. The electric reciprocating foot pedal control system according to claim 1, characterized in that, It also includes a swing amplitude control unit; The swing amplitude control unit is used to determine the target swing amplitude for the next reciprocating motion cycle based on the degree of active coordinated force and the degree of fatigue tremor determined by the physiological feature recognition unit during the reciprocating motion cycle after the foot pedal completes a complete reciprocating motion cycle.

10. The electric reciprocating foot pedal control system according to claim 9, characterized in that, The swing amplitude control unit is specifically used for: The actual swing amplitude of the foot pedal in the reciprocating motion cycle is determined based on the range of angular position changes of the foot pedal during the reciprocating motion cycle. The first amplitude adjustment amount is determined based on the degree of active coordinated force exertion during the reciprocating motion cycle and the first amplitude adjustment coefficient. The second amplitude adjustment amount is determined based on the degree of fatigue tremor during the reciprocating motion cycle and the second amplitude adjustment coefficient. The initial swing amplitude of the next reciprocating motion cycle is determined based on the actual swing amplitude of the reciprocating motion cycle, the first amplitude adjustment amount, and the second amplitude adjustment amount. If the initial swing amplitude is greater than the preset maximum swing amplitude, the preset maximum swing amplitude is determined as the target swing amplitude; If the initial swing amplitude is less than or equal to the preset maximum swing amplitude, the initial swing amplitude is determined as the target swing amplitude.

Images