Ladder four-bar mechanism optimization method, system and device based on dynamic modeling analysis

Abstract

The application belongs to the field of data processing and provides a dynamic modeling-based analysis ladder four-bar linkage optimization method, system and device, which can sample the four-bar linkage according to postures within the stroke, obtain a transmission angle sequence and an equivalent output torque sequence, calculate an effective correction angle along a force flow path according to an equivalent friction coefficient to obtain an effective transmission angle sequence, convert the effective transmission angle into a torque projection factor through a sine linkage system, back-propagate the equivalent output torque into a required input torque sequence, compare the peak value with an allowable input torque upper limit, and obtain a single control optimization parameter. The method combines friction circle correction with full-stroke peak modeling, converges complex multi-parameters into a single variable, directly connects the assistance and structure optimization, can highlight key postures, and can support cross-model reuse. According to the setting of spring pre-tightening or motor assistance, dead point avoidance and structure parameter optimization can be triggered, so that the peak operating force can be reduced, the sticking can be avoided, and the consistency and manufacturability can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of data processing, and particularly relates to a ladder four-bar linkage optimization method, system and device based on dynamic modeling analysis. BACKGROUND

[0002] In the process of unfolding and folding, ladders such as A-shaped ladders, platform ladders, articulated ladders, multi-section folding ladders, etc. generally use four-bar linkage mechanisms to realize opening and closing, limiting and force transmission. The mechanism needs to consider stable unfolding, smooth folding, avoidance of jamming and injury, control of the input force and torque required by the operator, and meet the requirements of lightweight and assembly tolerance throughout the stroke. In engineering practice, enterprises usually quickly give initial mechanism sizes through CAD assembly and geometric constraints, and then iterate through prototype trial and bench testing; the transmission performance is often checked by using transmission angle as a geometric index, and whether it is far from the dead point is often checked at several representative angles, and the load and feel are estimated by torque and force arm or the spring, gas spring or friction / clutch is selected according to experience to assist. Some enterprises will introduce multi-body dynamics (MBD) or finite element (FEA) for strength and motion simulation, but there is often a lack of unified data link between size optimization and assist setting. In order to reduce the user's operating force, improve the return feel and safety, more and more products are equipped with torsional springs, gas springs or motors, clutches and other devices. However, the force value, pre-tightening or current-torque setting of these components is still mainly based on trial and adjustment in existing practice, which depends on the experience of technicians, and the batch stability and traceability need to be improved.

[0003] The traditional method often checks whether the transmission angle meets the experience range at 1 to 3 representative angles, and lacks sequential modeling and peak value identification throughout the stroke. When the actual most unfavorable attitude is not checked, the prototype may be available, but the batch may be jammed or have excessive force. When the operator's required torque is calculated, the ideal hinge or constant efficiency is often estimated, and the influence of the pin hinge friction on the action line and effective transmission angle is not systematically introduced. As a result, the calculated input requirement is systematically small, and the prototype stage needs to be remedied by increasing the spring or increasing the current, which passively increases the development cycle and cost. For example, the patent document with the publication number CN112989498A provides a four-bar linkage tail door electric support rod output force calculation method, which can calculate the electric support rod output force size, important nodes and trajectory equation, but ignores or roughly handles the hinge friction, resulting in a prediction and measurement deviation, causing a waste of cost.

[0004] The existing process often determines whether assistance or modification is needed by subjective hand feeling and experience threshold, without unified quantitative comparison between required input torque under the most demanding posture and upper limit of product allowed input torque, so it is difficult to form consistent standards and automatic decisions across models. The specifications, pre-tightening settings and current settings of springs, gas springs or motors and clutches can usually be separated from geometric optimization, and the geometry is usually determined first and then the hand feeling is found by trial adjustment. However, there is a lack of calculable mapping between geometry and assistance, which often leads to a large number of trial iterations and non-reusable parameters.

[0005] Transmission angle and friction are sensitive to assembly deviation, surface treatment and lubrication state, and existing methods rarely evaluate the sensitivity and robustness of these key parameters, so it is difficult to ensure batch consistency, hand feeling and safety margin during the whole life cycle. For example, the patent document with publication number CN120316913A provides a humanoid robot leg four-bar mechanism design optimization method, which reduces the difficulty of establishing a complex model, but the assembly deviation of this method has the problem of insufficient stability, and the sensitivity is not high when monitoring wear and lubrication changes. There are many tools that can provide multiple curve reports, but they cannot converge complex calculations into a control quantity directly useful to engineers, such as passive pre-tightening or motor feed-forward torque target values, which leads to the inability to quickly solidify control strategies and manufacturing SOPs. SUMMARY

[0006] The purpose of the present application is to provide a dynamic modeling-based analysis of ladder four-bar mechanism optimization method, system and device to solve one or more technical problems existing in the prior art and at least provide a beneficial option or create conditions.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a dynamic modeling-based analysis of ladder four-bar mechanism optimization method is provided, the method comprising the following steps:

[0008] A dynamic model of the four-bar mechanism of the ladder is established to obtain a transmission angle sequence and an equivalent output torque sequence at a plurality of sampling postures within the stroke;

[0009] The upper limit of the allowed input torque of the four-bar mechanism, the equivalent friction coefficient and the number of pin hinges in the force flow path are obtained, and the friction angle is calculated by the inverse tangent function of the equivalent friction coefficient;

[0010] The effective correction angle is obtained by multiplying the friction angle by the number of pin hinges in the force flow path, and the effective transmission angle sequence is obtained by subtracting the effective correction angle at each sampling posture from the transmission angle sequence;

[0011] The effective transmission angle sequence is converted into a force dry factor sequence at each sampling posture by a sinusoidal relationship;

[0012] Dividing the equivalent output torque by the corresponding force factor at each sampling posture, a sequence of required input torques is obtained;

[0013] Taking the peak value of the sequence of required input torques as a peak required input torque, and determining a control optimization parameter based on the non-negative part of the difference between the peak required input torque and the upper limit of the allowable input torque.

[0014] Optimizing the control or the structural parameters of the four-bar linkage based on the control optimization parameter.

[0015] The method establishes a dynamic model according to sampling postures throughout the whole stroke to obtain a sequence of transmission angles and a sequence of equivalent output torques. The equivalent friction coefficient, the friction angle, and the effective correction angle of the link correct the transmission angle from posture to posture to form a sequence of effective transmission angles. The effective transmission angle from posture to posture is mapped to a force factor, and the equivalent output torque from posture to posture is back-propagated to a sequence of required input torques. The non-negative part of the difference between the peak value and the upper limit of the allowable input torque is obtained to obtain a control optimization parameter, which is used for optimization control and structural optimization.

[0016] The existing technology in the past is mostly static and single-posture geometric checking, for example, only the transmission angle at the extreme posture is considered, and the systematic influence of friction on the force transmission path is ignored. It is impossible to quantitatively merge the load demand under multiple postures into an executable control target, resulting in a design-control disconnection, and a lack of unified criteria for risk identification and quantitative compensation in the vicinity of the dead point.

[0017] The method converges the complex full-stroke stress, geometry, and friction problems into a scalar control optimization parameter, which directly drives the spring pre-tightening, motor assistance, or triggers structural modification. The peak value orientation avoids the risk of being masked by the average value, is more sensitive to the near-dead point section, and has higher reliability. The method can not only be used for algorithm control, like active and passive assistance settings, but also for structural size optimization to improve the minimum effective transmission angle and reduce the equivalent friction.

[0018] The above method is equivalent to the reduction of the effective transmission angle according to the friction circle theory, and the torque projection relationship with the sin(angle) function jointly determines the sharp rise of the input demand. Moreover, the non-negative single-variable output of the difference forms a unified safety margin quantification of the bearable capacity-actual demand, which is convenient for the control and manufacturing tolerance management of the electronic design model of the four-bar linkage.

[0019] Further, the equivalent friction coefficient of the four-bar linkage is the arithmetic mean of the friction coefficients at each hinge point of the four-bar linkage, or is obtained by weighted averaging the friction coefficients at each hinge point according to the path through which the force is transmitted from the input rod to the output rod in the four-bar linkage.

[0020] Further, the force flow path pin hinge number of the four-bar linkage is the number of hinges experienced by the force path from the input rod to the output rod.

[0021] Further, the transmission angle sequence and the equivalent output torque sequence are obtained by dynamic modeling of the four-bar linkage and sampling at equal steps within the stroke; the equivalent output torque is the synthesis of the gravity, self-weight distribution and external load of the four-bar linkage.

[0022] Further, the allowable input torque upper limit is the maximum force value that the four-bar linkage can accept as input. Preferably, the allowable input torque upper limit can be obtained by inputting a preset threshold value.

[0023] Further, the effective transmission angle sequence at each sampling posture is converted into a force factor sequence through a sine relationship, specifically:

[0024] The effective transmission angle at each sampling posture in the transmission angle sequence is converted into a sine function value of the effective transmission angle at each sampling posture through a sine function;

[0025] The sine function values of the effective transmission angle at each sampling posture are combined to form the force factor sequence;

[0026] Alternatively, the sum of the sine function values of the effective transmission angle at each sampling posture is calculated, and the ratio of the exponential result of the sine function value of the effective transmission angle at each sampling posture to the sum of the sine function values of the effective transmission angle is calculated to form the force factor sequence.

[0027] In the prior art, when only the original sine value is used, the cross-posture aggregation or distribution is often averaged by the medium posture, and the key posture is not highlighted. In the control table distribution and multi-posture comprehensive evaluation, there is a lack of stable and adjustable sensitivity weighting mechanism.

[0028] The direct sine of the present application can maintain one-to-one correspondence with geometry / mechanics, is suitable for input torque backstepping for each posture, and can accurately locate the peak value. This method can adjust the mechanical advantages and risk postures, suppress the masking effect of non-key postures, and thus be more robust to noise and dispersion in multi-posture synthesis, such as distribution and comprehensive indicators of structural design.

[0029] Our method is designed in this way because the sine projection approximates the mechanical advantage, has a comparable geometric proxy between speed and torque, and can be monotonically associated with the effective transmission angle. Moreover, the exponential processing is essentially a nonlinear amplification of adjustable gain: the larger the alpha, the stronger the separation of large / small values, so as to highlight the key postures and weaken the secondary postures in weight distribution, and achieve more reasonable distribution of assistance, pre-tightening, etc. on resources.

[0030] Further, a non-negative part of a difference between the peak required input torque and the upper limit of the allowed input torque is determined as a control optimization parameter, specifically:

[0031] A ratio of the peak required input torque to the upper limit of the allowed input torque is calculated as a required torque prominence ratio.

[0032] According to whether the numerical value of the required torque prominence ratio is greater than 1, it is judged whether optimization control or structural parameter optimization of the four-bar linkage mechanism is needed.

[0033] When the required torque prominence ratio is greater than 1, optimization control or structural parameter optimization of the four-bar linkage mechanism is performed: a difference between the peak required input torque and the upper limit of the allowed input torque is calculated as a required torque prominence difference, and a larger value of the required torque prominence difference and zero is obtained as a control optimization parameter T, which is used for optimization of the four-bar linkage mechanism.

[0034] Wherein, the required torque prominence ratio K=(peak required input torque) / (upper limit of allowed input torque) can be defined, and K>1 is taken as a criterion for triggering optimization; the control optimization parameter=non-negative part of the difference (i.e. τ_ctrl) is defined as the same control optimization input.

[0035] The prior art lacks unified and objective criteria for when to need assistance, pre-tightening or modification, and engineers often rely on experience to debug, which is time-consuming and unstable. In addition, standards are different under different models and human factors, making it difficult to compare horizontally and automate.

[0036] The method of the present application gives a clear one-key judgment: K≤1 is qualified, and K>1 must be optimized; the single variable τ_ctrl directly enters the control / selection process, significantly reducing the number of parameter adjustment rounds. This can facilitate cross-product comparison, horizontal evaluation under the same M_allow (upper limit of allowed input torque), and batch generation of controls. Among them, the peak is a representative of the most demanding working condition of the mechanism, which is highly related to user experience and failure risk. The difference is taken as a non-negative value, which can form a safety margin quantization, naturally match the rated parameters of controls / springs / clutches, and ensure implementability and verifiability.

[0037] Further, based on the control optimization parameter, the four-bar linkage mechanism is optimized in control or structural parameter, specifically:

[0038] The control optimization parameter is mapped to a pre-tightening torque of a spring or gas spring provided in the four-bar linkage mechanism.

[0039] And / or the control optimization parameter is mapped to an assistance target of a motor or clutch provided in the four-bar linkage mechanism.

[0040] The application maps τ_ctrl to the spring / air spring pre-tightening torque of a passive device or to the motor / clutch assistance target of an active device. A structure optimization branch can also be given, such as adjusting the rod length and hinge position to raise the minimum effective transmission angle or reduce the equivalent friction.

[0041] The design results of the prior art cannot be directly closed-loop to manufacturing / control parameters, resulting in inaccurate calculation and installation, and simply increasing assistance may cover up the root cause of low transmission angle / high friction, which leads to poor long-term stability.

[0042] The same τ_ctrl described in the application can drive passive or active schemes, shorten the prototype debugging period. First control and then structure / first structure and then control can also be implemented, taking into account cost and reliability. When τ_ctrl exceeds the hardware limit, automatically switch to structure optimization to avoid blind stacking. This is because τ_ctrl is a physical homogenous quantity of required torque capacity, which corresponds to spring pre-tightening, motor rating, and clutch holding torque. Raising the minimum effective transmission angle or reducing friction on the structure side will monotonically reduce the peak demand, forming a direct negative feedback with τ_ctrl, and the closed-loop can converge to a manufacturable and controllable target area.

[0043] The application also provides a ladder four-bar mechanism optimization system based on dynamic modeling analysis, which comprises a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the ladder four-bar mechanism optimization method based on dynamic modeling analysis are implemented. The ladder four-bar mechanism optimization system based on dynamic modeling analysis can run on desktop computers, notebook computers, palm computers, and cloud data centers, and the executable system can include, but is not limited to, a processor, a memory, a server cluster, and the like. The processor executes the computer program running in the following system units:

[0044] An acquisition correction unit is configured to calculate a friction angle from an equivalent friction coefficient by an inverse tangent function, multiply the friction angle by the number of pin hinges in the force flow path to obtain an effective correction angle, and subtract the effective correction angle from the transmission angle sequence at each sampling posture to obtain an effective transmission angle sequence.

[0045] A conversion factor unit is configured to convert the effective transmission angle sequence into a force coefficient sequence by a sine relationship, and divide the equivalent output torque by the corresponding force coefficient to obtain a required input torque sequence.

[0046] A calculation parameter unit is configured to take the peak value of the required input torque sequence as a peak required input torque, and determine a control optimization parameter from the non-negative part of the difference between the peak required input torque and the upper limit of the allowable input torque.

[0047] The control optimization unit is used to optimize the control or structural parameters of the four-bar linkage based on the control optimization parameters.

[0048] Correspondingly, the present invention also provides an electronic device, a readable storage medium, and a computer program product:

[0049] An electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method for optimizing a ladder four-bar linkage based on dynamic modeling analysis and the steps thereof.

[0050] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to execute the method for optimizing a ladder four-bar linkage based on dynamic modeling analysis and the steps thereof.

[0051] A computer program product includes a computer program that, when executed by a processor, implements the optimization method for a four-bar linkage based on dynamic modeling analysis and the methods for each step therein.

[0052] The beneficial effects of this invention are as follows: This invention provides a method, system, and device for optimizing a ladder four-bar linkage based on dynamic modeling analysis. The effective transmission angle is converted into a torque projection factor through sinusoidal statistical analysis. The equivalent output torque is then regressed to the required input torque sequence for each posture. The peak value is compared with the upper limit of the allowable input torque to obtain a single control optimization parameter. This method combines friction circle correction with full-stroke peak modeling, converging complex multi-parameter parameters into a single variable. Direct connection assistance and structural optimization highlight key postures and support cross-model reuse. Based on this, setting spring preload or motor assistance can trigger dead-point avoidance and structural parameter optimization, thereby reducing peak operating force, preventing jamming, and improving consistency and manufacturability. Attached Figure Description

[0053] The above and other features of the present invention will become more apparent from the detailed description of the embodiments shown in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals denote the same or similar elements. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort. In the drawings:

[0054] Figure 1 The flowchart shown is a process for optimizing a four-bar linkage mechanism based on dynamic modeling analysis.

[0055] Figure 2 The figure shown is a system structure diagram of the ladder four-bar linkage optimization system based on dynamic modeling analysis. Detailed Implementation

[0056] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0057] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0058] like Figure 1 The diagram shown is a flowchart of the optimization method for a ladder four-bar linkage based on dynamic modeling analysis according to the present invention. The following is a combination of... Figure 1 This paper describes the optimization method, system, and equipment for a ladder four-bar linkage based on dynamic modeling analysis according to embodiments of the present invention.

[0059] This invention proposes an optimization method for a ladder four-bar linkage based on dynamic modeling and analysis. The method specifically includes the following steps:

[0060] A dynamic model of the four-bar linkage of the ladder is established to obtain the transmission angle sequence and equivalent output torque sequence under several sampled postures within the stroke; the upper limit of the allowable input torque, the equivalent friction coefficient and the number of pins in the force flow path of the four-bar linkage are obtained.

[0061] The friction angle is obtained by calculating the equivalent friction coefficient using the arctangent function. The effective correction angle is obtained by multiplying the friction angle by the number of pins in the force flow path. The effective correction angle is then subtracted from the transmission angle sequence under each sampling posture to obtain the effective transmission angle sequence.

[0062] The effective transmission angle sequence is converted into a force interference factor sequence using a sine relationship. The equivalent output torque is divided by the corresponding force interference factor to obtain the required input torque sequence.

[0063] The peak value of the required input torque sequence is taken as the peak required input torque, and the control optimization parameters are determined by the non-negative part of the difference between the peak required input torque and the upper limit of the allowed input torque.

[0064] Based on the aforementioned control optimization parameters, the four-bar linkage is subjected to optimized control or structural parameter optimization.

[0065] In some embodiments, the step of optimizing control or structural parameters of the four-bar linkage includes setting spring / air spring pre-tightening or motor / clutch assistance; or adjusting the length of the rods and the position of the hinges to increase the minimum effective transmission angle or reduce friction. And, or adjusting the length of the rods and the position of the hinges to increase the minimum effective transmission angle or reduce equivalent friction.

[0066] In some embodiments, the four-bar linkage is a basic mechanical transmission mechanism composed of four rigid components connected by lower pairs, widely used in various machines and instruments. The four-bar linkage is a planar mechanism composed of four rigid components (rods) connected by pin hinge points (such as revolute pairs and prismatic pairs), which are divided into four rigid components: the frame, the input rod, the output rod, and the connecting rod, which are connected by revolute pairs. Its basic feature is that all components move in the same plane, and is usually used to convert one form of motion into another, such as converting rotational motion into reciprocating motion. The ends of each rod of the four-bar linkage are connected by hinge points, and the friction coefficient at the hinge point connection is called the pin hinge friction coefficient. In CAD modeling of the four-bar linkage, a base axis is determined. For example, the base axis can be a fixed rod in the four-bar linkage and the straight line it lies on, or an axis in the CAD modeling.

[0067] In CAD, the length of each rod of the four-bar linkage can be obtained by selecting two hinge centers to measure the distance with tools such as Measure, or by limiting the hinge points with assembly fits such as Mate software tools to read the dimensions. The coordinates of the four hinge points in the plane are obtained by establishing a reference coordinate system and sketching points in CAD, such as reading the XYZ axes and coordinate points with Measure. The base axis distance can be the distance between the two hinge points on the fixed base of the four-bar linkage model.

[0068] The input angle is the angle of the driving rod relative to the base, indexed by the stroke sampling. In assembly, the input shaft is set with an angle fit, which can be scanned in Motion Study, such as 0° to 180°, which is recorded step by step. The output angle is obtained from the angle of the rod relative to the base. For example, for a four-bar linkage with one degree of freedom, only one-dimensional scanning angle is needed to cover the motion interval.

[0069] Then, in the stroke of one cycle of reciprocating motion, for example, the stroke of one cycle of four-bar linkage rotation is 360°, and the attitude obtained every 10° of rotation is taken as a sample attitude, so there are 36 sample attitudes in one cycle of stroke, or the attitude obtained every 120° of rotation is taken as a sample attitude, and there are 3 sample attitudes. At each sample attitude, the included angle between the connecting rod and the base axis or the output rod is obtained, respectively, as the transmission angle of each sample attitude.

[0070] The equivalent output torque of each sampling posture can be the resultant torque that the four-bar linkage needs to overcome at the specified sampling posture, including the synthesis of the forces of gravity, self-weight distribution, external load, and human-machine operation load of the four-bar linkage at the sampling posture. For example, it can be the sum of the gravity torque of the rod and the external load torque, sometimes it can also be the numerical sum of the torque of the force in each direction measured by the torque wrench, torque sensor, etc. at the posture to maintain balance at the given posture of the four-bar linkage, or more simply it can also be the numerical value of the turning torque obtained by the simulation system when the load is applied to the four-bar linkage in the simulation.

[0071] The allowable input torque upper limit is the maximum force value that the four-bar linkage can accept at each sampling posture. For example, when using a motor or an engine as the power input source of the input rod of the four-bar linkage, the maximum output operating torque that the motor can accept or the rated peak value of the engine or actuator can be used as the allowable input torque upper limit.

[0072] The equivalent friction coefficient can be obtained by the parameters of the properties of the material at the hinge joint. For example, the steel-steel dry friction coefficient is about 0.4-0.8, and after lubrication it can be reduced to about 0.16 or lower; the bronze bushing-steel shaft is about 0.08-0.16, and mixed lubrication can be as low as 0.02-0.08. If the friction coefficients at the hinge points are different due to different materials, the arithmetic mean of the friction coefficients at the hinge points can be used as the pin hinge friction coefficient of the four-bar linkage.

[0073] The number of pin hinges in the force flow path is the number of pin hinges through which the main force flows from the force input rod to the output rod, which is used to accumulate the friction angle and friction loss of the four-bar linkage in reciprocating motion. For example, the number of pin hinges in the force flow path of the four-bar linkage mechanism is counted one by one, which is generally 1-3, and the number of pin hinges in the force flow path of the four-bar linkage is generally 3, which is uniformly applicable to each rod of the four-bar linkage in the calculation.

[0074] The transmission angle is defined as the included angle between the coupling rod and the output rod, and the transmission angle sequence is a sequence composed of the transmission angles of the four-bar linkage at each sampling posture. The equivalent output torque includes the synthesis of gravity, self-weight distribution, and external load, and the equivalent output torque sequence is a sequence composed of the equivalent output torques of the four-bar linkage at each sampling posture.

[0075] The optimization control can further include triggering a dead point avoidance rule when the effective transmission angle is lower than a preset threshold, and the preset threshold is used to limit the lower bound of the effective transmission angle and the lower bound of the change rate thereof. Triggering the dead point avoidance rule when the effective transmission angle is lower than the preset threshold is a step of optimizing the control or the structural parameters of the four-bar linkage mechanism at the most difficult posture.

[0076] Further, the equivalent friction coefficient of the four-bar linkage is an arithmetic mean of the friction coefficients at the hinge points of the four-bar linkage, or a weighted average of the friction coefficients at the hinge points according to a force flow path of the four-bar linkage from the input rod to the output rod.

[0077] Further, the number of hinge points in the force flow path of the four-bar linkage is the number of hinge points experienced by the force flow path from the input rod to the output rod.

[0078] Further, the sequence of effective output torques is obtained by dynamic modeling of the four-bar linkage mechanism and sampling at equal steps within the stroke; and the effective output torque is a synthesis of the gravity, self-weight distribution and external load of the four-bar linkage.

[0079] Further, the allowable input torque upper limit is the maximum force value that the four-bar linkage can accept as input. Preferably, the allowable input torque upper limit can be obtained by inputting a preset threshold value.

[0080] Further, the sequence of effective transmission angles is converted into a sequence of force factors at each sampling posture by a sine relationship, specifically:

[0081] The sine function value of the effective transmission angle at each sampling posture in the sequence of transmission angles is obtained by a sine function;

[0082] The sine function value of the effective transmission angle at each sampling posture is used to form the sequence of force factors;

[0083] Alternatively, the sum of the sine function values of the effective transmission angle at each sampling posture is calculated, and the ratio of the exponential result of the sine function value of the effective transmission angle at each sampling posture to the sum of the sine function values of the effective transmission angle is used to form the sequence of force factors.

[0084] The peak required input torque is the maximum value of the sequence of required input torques at all sampling postures. Preferably, the maximum value in the sequence of required input torques is selected as the peak required input torque, and the rod corresponding to the peak required input torque is selected as the selected sampling posture.

[0085] Further, the non-negative part of the difference between the peak required input torque and the allowable input torque upper limit is used to determine the control optimization parameter, specifically:

[0086] The ratio of the peak required input torque to the allowable input torque upper limit is calculated as the required torque prominence rate.

[0087] According to whether the required torque prominence rate is greater than 1, it is determined whether optimization control or structural parameter optimization of the four-bar linkage mechanism is needed.

[0088] When the required torque prominence rate is greater than 1, the four-bar linkage mechanism is optimized in control or structure parameters: the difference between the peak required input torque and the upper limit of the allowable input torque is calculated as the required torque prominence difference, and the greater value of the required torque prominence difference and zero is taken as the control optimization parameter T, which is used to optimize the four-bar linkage mechanism.

[0089] Further, based on the control optimization parameter, the four-bar linkage mechanism is optimized in control or structure parameters, specifically:

[0090] The control optimization parameter is mapped to the pre-tightening torque of the spring or gas spring provided in the four-bar linkage mechanism;

[0091] And / or the control optimization parameter is mapped to the assist target of the motor or clutch provided in the four-bar linkage mechanism.

[0092] In some embodiments, specifically for example, the control optimization parameter is mapped to the pre-tightening torque of the spring or gas spring provided in the four-bar linkage mechanism: the optimization control torque T is used to optimize the torque of the four-bar linkage, and the required input torque of the four-bar linkage is raised to 24.44 Nm, which exceeds the upper limit of the allowable input torque of 15 Nm. Therefore, the control optimizer only needs to output a variable T = 9.44 Nm; if a spring or gas spring is used, T is mapped to the pre-tightening torque or equivalent force arm. The control optimization parameter is mapped to the assist target of the motor or clutch provided in the four-bar linkage mechanism: if a motor or clutch is used, T is used as the assist target; if T exceeds the hardware limit, it needs to be returned to the geometric level to raise the minimum transmission angle, for example, to the 40°-120° interval, or to reduce friction, such as adding multi-point lubrication, setting a bearing, etc.

[0093] For example, according to the upper limit of the allowable input torque, a spring is used for passive assist, and the spring provides an equivalent force arm of ≥9.44 Nm in the most difficult, most sluggish or slowest posture of the four-bar linkage during reciprocating motion, and the rest of the postures are assisted as little as possible. If the torsion spring directly works on the fixed hinge point of the four-bar linkage, the force arm is the length of the rod as the shaft radius. If the shaft radius is only 10-12 mm, the equivalent side force will be larger. Then, the spring needs a pre-tightening of 9.44 Nm. Take 9.44 Nm as the pre-tightening target, and multiply it by a certain safety factor to get the force range to be twisted during assembly. If the target is 9.44 Nm, take a little more, and the assembly pre-tightening target can be about 11.8 Nm. Use a small torque wrench or a simple force arm jig to twist it to 11.8 Nm according to the jig scale.

[0094] Or for example, determine the vertical distance of the pivot axis of the gas spring push rod relative to the four-bar linkage when rotating, which is the effective force arm in the most difficult posture of the four-bar linkage. In the most difficult posture, that is, at the moment when the rotation is the slowest, the corresponding gas spring force of the four-bar linkage × the effective force arm ≥ 9.44 Nm. For example, at the most difficult posture, the measured effective force arm is 180 mm, about 0.18 m, and it requires a pushing force of 9.44 Nm ÷ 0.18 m ≈ 52 N. If the force factor of the rod at this time is about 0.6, the nominal force value of the gas spring should be no less than 52 N ÷ 0.6 ≈ 87 N, so a 100 N grade gas spring can be selected and set to assist the four-bar linkage to fine-tune and ensure that the prototype can pass that posture, and it will not assist at other times.

[0095] There is an embodiment one, after establishing a dynamic model and completing the assembly of the ladder four-bar linkage mechanism, a sampling posture s in the working stroke is selected, and the data of the posture is obtained from CAD measurement and a parameter table, mainly including:

[0096] The four-bar linkage has four hinge points, which can be marked as A, B, C, and D, and a point E of force of a hand or a motor, for example, when the weight of the rear foot of the fixed four-bar linkage is measured as 8.746108 N, the vertical distance from point A to the center of gravity of the rear foot is 31.7865 mm, the distance from point B to the action point E of the hand is 197.8 mm, the distance from point D to the action point E of the hand is 197.8 mm, the distance from A to D is 275.9548 mm, the distance from C to D is 131.9133 mm, and the distance from C to B is 91 mm;

[0097] The posture angle ∠BCD = 12.6552°, and the transmission angle ∠CBA = 4.5751°;

[0098] The hinge friction circle radius (A / B / C / D) is 1.5 mm;

[0099] The equivalent friction coefficient fv is given in two groups, 0.5 and 1.0;

[0100] The number of pin hinges in the force flow path is 3, and the force flows through B, C, and D;

[0101] The upper limit of the allowable input torque is 0.60 N·m on the handle side, which corresponds to a force of no more than 3 N on a force arm of about 0.2 m of the handle. It can be adjusted according to the specific product type.

[0102] The transmission angle of the posture s is 4.5751°, and the equivalent output torque is calculated by taking point A as the torque point. First, multiply the weight of the rear foot by the vertical distance from point A to the center of gravity to obtain the gravitational rotation effect about point A, which is about 278.01 N·mm; then, along the current geometric relationship of the mechanism, the effect is sequentially converted to the hand action point E for subsequent back-propagation of the input demand.

[0103] The equivalent output torque is back-projected to the hand point E along the current pose projection relationship: 3.206°, indicating that the pose is located in the disadvantaged zone, close to the dead point of the mechanism motion, and the subsequent projection is in absolute quantity.

[0104] The effective transmission angle is converted to the force factor of the current pose through the sine relationship: fv=0.5, the calculated force factor is about 0.0120; fv=1.0, the calculated force factor is about 0.055. If the full stroke is sampled, a force factor can be obtained for each pose, forming a force factor sequence.

[0105] The equivalent output torque is back-projected to the hand point E along the current pose projection relationship:

[0106] In the control group without considering friction, the required force of point E is about 1.845N; multiplied by the force arm of point E 0.1978m, the required input torque on the handle side is about 0.365N·m;

[0107] In the control group considering friction, fv=0.5, the required force of point E is about 2.439N; the corresponding required input torque on the handle side is about 0.482N·m;

[0108] Considering friction, fv=1.0, the required force of point E is about 3.768N; the corresponding required input torque on the handle side is about 0.745N·m.

[0109] If the full stroke is sampled, a required input torque can be obtained for each pose, forming a required input torque sequence.

[0110] In the demonstration of only this pose s, the required input torque of the pose can be directly regarded as the peak value of the current pose; if the full stroke is sampled, the maximum value of the required input torque sequence is taken as the peak value of the required input torque.

[0111] Taking the upper limit of the allowable input torque 0.60N·m as the criterion, the control optimization parameters are obtained, taking the non-negative part of the difference:

[0112] Without considering friction: 0.365 0.60 takes 0, no optimization is needed;

[0113] fv=0.5: 0.482 0.60 takes 0, no optimization is needed;

[0114] fv = 1.0: 0.745 0.60 take 0.145 N·m, need to optimize.

[0115] Therefore, in the case of fv = 1.0, the posture s, the control optimization parameter = 0.145 N·m.

[0116] If passive assistance is used, 0.145 N·m is taken as the minimum pre-tightening torque target of the gas spring / torsion spring; for example, when the handle effective force arm is about 0.20 m, the corresponding minimum assistance is about 0.73 N.

[0117] If active assistance is used, 0.145 N·m is written into the controller as the peak value of the feedforward torque, and the remaining postures are distributed according to the required input torque sequence, which is converted into current targets after being converted by the reducer and setting the amplitude limit.

[0118] If the control margin is insufficient or further cost reduction is needed, go back to the structure layer for parameter optimization, such as increasing the minimum effective transmission angle, fine-tuning the hinge position, or reducing the equivalent friction, and then recalculate the above process.

[0119] Under the sampling posture s of the present embodiment, if friction is not considered, the required input torque on the handle side is about 0.365 N·m; when considering friction, the required input torque on the handle side increases from 0.482 N·m to 0.745 N·m as the equivalent friction coefficient increases from 0.5 to 1.0. Under the constraint of the allowed upper limit of the input torque 0.60 N·m, the obtained single-variable control optimization parameter is 0.145 N·m, by which the pre-tightening / assistance can be directly set, or structural optimization for the minimum effective transmission angle and equivalent friction can be triggered.

[0120] There is a second embodiment, when the four-bar linkage mechanism is scanned at equal steps, the effective transmission angles of a plurality of sampling postures are obtained, and the force factor sequence is obtained in two ways:

[0121] The effective transmission angle of each sampling posture is converted by a sine relationship to obtain the original force factor first;

[0122] The above original factor is transformed by index one by one, and the sum of the index results of all sampling postures is normalized to form an index processing ratio sequence. To enhance the discrimination, a sensitivity coefficient a (a > 0) can be selected to adjust the sensitivity of the index; the larger a is, the more sensitive to large values. The said sensitivity coefficient is a weight coefficient that is multiplied by the original force factor before index transformation to amplify it.

[0123] The following is an example of the center posture s under the same working condition as example one, taking its adjacent two frames and two end postures for demonstration; the effective transmission angles are [16.111, 8.111, 0.686, 6.111, 11.111] (unit: °) in turn, and the third frame is the posture s. Five sampling postures are adopted, which are 360 degrees in one cycle, with one posture sampled every 60 degrees, a total of 6 postures, but the last posture in 360 degrees coincides with the starting posture of the four-bar linkage at rest, so it is discarded, leaving five sampling postures.

[0124] In the present embodiment, in order to illustrate the difference between the direct sine method and the exponential processing method in calculating the force link factor, five sampling postures under the same working condition as example one are selected for comparison, denoted as s1, s2, s*, s4 and s5 respectively, wherein s* is the center posture of s. The effective transmission angles of each sampling posture are 16.111°, 8.111°, 0.686°, 6.111° and 11.111° in turn.

[0125] When the direct sine method is used for calculation, the force link factors of the five sampling postures are about 0.278, 0.141, 0.012, 0.106 and 0.193 respectively. It can be seen that the projection factor of the posture s* in the near dead point position is only 0.012, which is significantly lower than that of the other postures, indicating that the mechanical force transmission efficiency of this posture is the lowest.

[0126] When the exponential processing method is used, taking the sensitivity coefficient α=5 as an example, the exponential processing ratios of the five postures are 0.351, 0.177, 0.093, 0.149 and 0.230 in turn, and the sum is 1.000. It can be seen that after exponential processing, the posture s1 with obvious geometric advantage is given a higher weight of 0.351, while the weight of the disadvantaged posture s* is only 0.093.

[0127] When the sensitivity coefficient is further increased to α=10, the comparison result is more prominent: the ratios of the five postures are 0.517, 0.132, 0.036, 0.093 and 0.221 in turn, and the sum is also 1.000. At this time, the weight of posture s1 is further increased to 0.517, while the weight of s* is only 0.036, which is basically weakened.

[0128] From the above comparison, it can be seen that the direct sine method reflects the geometric projection amount of each posture itself, while the exponential processing method realizes the weight distribution across postures through exponential transformation, so that the weight of the posture with high force transmission efficiency is increased, while the weight of the posture close to the dead point is weakened. When α is 5, a good degree of differentiation can be obtained; when α is 10, the algorithm is more sensitive to the mechanically advantageous postures, and is suitable for use in scenarios where the sampling is dense throughout the stroke.

[0129] In the subsequent torque back-propagation and control parameter generation, both of the two modes of our product can be used: the direct sine mode is used for real-time back-propagation calculation for each posture, and the exponential processing mode is used for weighted combination of multi-posture results or optimization of the torque distribution table of the controller, so as to realize a more smooth and conservative overall control strategy.

[0130] The dynamic modeling analysis-based ladder four-bar mechanism optimization system runs in any computing device of a desktop computer, a notebook computer, a palm computer or a cloud data center, and the computing device comprises a processor, a memory and a computer program stored in the memory and running on the processor, and the processor implements the steps in the dynamic modeling analysis-based ladder four-bar mechanism optimization method when the computer program is executed.

[0131] The dynamic modeling analysis-based ladder four-bar mechanism optimization system provided by the embodiment of the application comprises a processor, a memory and a computer program stored in the memory and running on the processor, the processor implements the steps in the dynamic modeling analysis-based ladder four-bar mechanism optimization method when the computer program is executed, and the processor is executed in the following system units: Figure 2 The dynamic modeling analysis-based ladder four-bar mechanism optimization system provided by the embodiment of the application comprises a processor, a memory and a computer program stored in the memory and running on the processor, the processor implements the steps in the dynamic modeling analysis-based ladder four-bar mechanism optimization method when the computer program is executed, and the processor is executed in the following system units:

[0132] The acquisition correction unit is configured to calculate a friction angle from the equivalent friction coefficient by an inverse tangent function, multiply the friction angle by the number of pin hinges in the force flow path to obtain an effective correction angle, and subtract the effective correction angle from the transmission angle sequence at each sampling posture to obtain an effective transmission angle sequence.

[0133] The conversion factor unit is configured to convert the effective transmission angle sequence into a force coefficient sequence by a sine relationship, and divide the equivalent output torque by the corresponding force coefficient to obtain a required input torque sequence.

[0134] The calculation parameter unit is configured to take the peak value of the required input torque sequence as a peak required input torque, and determine a control optimization parameter from the non-negative part of the difference between the peak required input torque and the upper limit of the allowed input torque.

[0135] The control optimization unit is configured to perform optimization control or structure parameter optimization on the four-bar mechanism based on the control optimization parameter.

[0136] In order to better unify the linear relationship and probability relationship of the numerical values of physical quantities of different units, dimensionless processing can be performed between different physical quantities.

[0137] Preferably, all undefined variables in the present application, if not explicitly defined, can be threshold values set by human.

[0138] The dynamic modeling analysis-based ladder four-bar mechanism optimization system can be run in a desktop computer, a notebook computer, a palm computer, and a cloud data center, etc. The dynamic modeling analysis-based ladder four-bar mechanism optimization system includes, but is not limited to, a processor and a memory. Those skilled in the art can understand that the example is only an example of the dynamic modeling analysis-based ladder four-bar mechanism optimization method, system and device, and does not constitute a limitation on the dynamic modeling analysis-based ladder four-bar mechanism optimization method, system and device, and can include more or fewer components, or combine certain components, or different components, for example, the dynamic modeling analysis-based ladder four-bar mechanism optimization system can also include an input / output device, a network access device, a bus, etc.

[0139] The present application also provides an electronic device, a readable storage medium and a computer program product:

[0140] An electronic device includes at least one processor and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the dynamic modeling analysis-based ladder four-bar mechanism optimization method and the steps therein.

[0141] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable the computer to execute the dynamic modeling analysis-based ladder four-bar mechanism optimization method and the steps therein.

[0142] A computer program product includes a computer program, which, when executed by a processor, implements the dynamic modeling analysis-based ladder four-bar mechanism optimization method and the steps therein.

[0143] Wherein, the electronic device is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not intended to limit the implementations of the present application described and / or claimed in this document.

[0144] The various embodiments of the systems and techniques described above can be implemented in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a load programmable logic device (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0145] Program code to implement methods of the present application can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, produces a means for implementing the functions / acts specified in the flowcharts and / or block diagrams. The program code can be executed entirely on a machine, partially on a machine, partially on a machine as a stand-alone software package, or entirely on a remote machine or server.

[0146] In the context of the present application, a machine-readable medium can be a tangible medium that contains or stores a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can include but is not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine-readable storage medium will include one or more lines of electrical connections, portable computer disks, hard disk drives, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fiber, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0147] ​To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0148] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0149] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0150] The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The processor is the control center of the dynamic modeling analysis-based ladder four-bar mechanism optimization system, and is connected to each sub-region of the dynamic modeling analysis-based ladder four-bar mechanism optimization system through various interfaces and lines.

[0151] The memory can be used to store the computer programs and / or modules, and the processor realizes various functions of the dynamic modeling analysis-based ladder four-bar mechanism optimization method, system and device by running or executing the computer programs and / or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area. The program storage area can store an operating system, at least one application program required for a function (such as a sound playing function, an image playing function, etc.), etc.; and the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0152] It should be understood that the various forms of flow shown above can be reordered, added or deleted steps. For example, the steps described in the present disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions of the present disclosure can be achieved, and the present disclosure is not limited herein.

[0153] The application provides a ladder four-bar linkage optimization method and system based on dynamic modeling analysis, which can sample the four-bar linkage according to the posture in the stroke, obtain a transmission angle sequence and an equivalent output torque sequence; a friction angle is calculated according to an equivalent friction coefficient, and is accumulated as an effective correction angle along a force flow path to obtain an effective transmission angle sequence; the effective transmission angle is converted into a torque projection factor through a sine linkage system, the equivalent output torque is back-propagated into a required input torque sequence, and a peak value is compared with an allowable input torque upper limit to obtain a single control optimization parameter. The method combines the friction circle correction with the full-stroke peak modeling, converges the complex multi-parameter of the four-bar linkage electronic design model into a single variable, and directly connects the power assistance and the structure optimization, so that the key postures can be highlighted, and cross-model reuse can be supported.

[0154] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing and optimizing a ladder four-bar mechanism based on dynamic modeling, characterized in that, The method comprises: a dynamic model of the four-bar linkage of the ladder is established, and a transmission angle sequence and an equivalent output torque sequence of the dynamic model at a plurality of sampling postures within a stroke are obtained; an upper limit of an allowable input torque, an equivalent friction coefficient and a number of pin hinges in a force flow path of the four-bar linkage are obtained, and the equivalent friction coefficient is calculated by an inverse tangent function to obtain a friction angle; the friction angle is multiplied by the number of pin hinges in the force flow path to obtain an effective correction angle, and the transmission angle sequence is subtracted by the effective correction angle at each sampling posture to obtain an effective transmission angle sequence; the effective transmission angle sequence is converted into a force dry factor sequence at each sampling posture by a sine relationship; the equivalent output torque is divided by the corresponding force dry factor at each sampling posture to obtain a required input torque sequence; a peak value of the required input torque sequence is taken as a peak required input torque, and a non-negative part of a difference between the peak required input torque and the upper limit of the allowable input torque is used to determine a control optimization parameter; based on the control optimization parameter, the four-bar linkage is controlled or optimized in structure.

2. The method of claim 1, wherein, wherein, the equivalent friction coefficient of the four-bar linkage is an arithmetic mean of friction coefficients at each hinge point of the four-bar linkage, or is obtained by weighted averaging the friction coefficients at each hinge point according to a path through which force is flowed from a force-receiving input rod to an output rod in the four-bar linkage.

3. The method of claim 2, wherein, wherein, the number of pin hinges in the force flow path of the four-bar linkage is a number of hinge points experienced by a force path from the input rod to the output rod.

4. The method of claim 1, wherein, wherein, the transmission angle sequence and the equivalent output torque sequence are obtained by dynamic modeling of the four-bar linkage and equal-step scanning sampling within a stroke; and the equivalent output torque is a combination of gravity and external load of the four-bar linkage.

5. The method of claim 1, wherein, wherein, the upper limit of the allowable input torque is a maximum force value that can be accepted by the four-bar linkage.

6. The dynamic modeling analysis based optimization method of a ladder four-bar mechanism according to any one of claims 1 to 5, wherein, wherein, the effective transmission angle sequence is converted into the force dry factor sequence at each sampling posture by the sine relationship, specifically: a sine function value of the effective transmission angle at each sampling posture in the effective transmission angle sequence is calculated to obtain a sine function value of the effective transmission angle at each sampling posture; the sine function values of the effective transmission angle at each sampling posture are combined to form the force dry factor sequence; alternatively, a sum of the sine function values of the effective transmission angle at each sampling posture is calculated, and a ratio of an exponential result of the sine function value of the effective transmission angle at each sampling posture to the sum of the sine function values of the effective transmission angle is calculated to form the force dry factor sequence.

7. The method of claim 6, wherein, the non-negative part of the difference between the peak required input torque and the upper limit of the allowable input torque is used to determine the control optimization parameter, specifically: a ratio of the peak required input torque to the upper limit of the allowable input torque is calculated as a required torque prominence rate; whether the four-bar linkage needs to be controlled or optimized in structure is determined according to whether the required torque prominence rate is greater than 1. When the required torque protrusion rate is greater than 1, the four-bar linkage mechanism is optimized in control or structure parameters: the difference between the peak required input torque and the upper limit of the allowable input torque is calculated as the required torque protrusion difference, and the greater value of the required torque protrusion difference and zero is obtained as the control optimization parameter, and the control optimization parameter is used to optimize the four-bar linkage mechanism.

8. The method of claim 6, wherein, Wherein, Based on the control optimization parameter, the four-bar linkage mechanism is optimized in control or structure parameters, specifically: The control optimization parameter is mapped to the pre-tightening torque of the spring provided by the four-bar linkage mechanism; And / or the control optimization parameter is mapped to the assist target of the motor provided by the four-bar linkage mechanism.

9. A system for analyzing and optimizing a ladder four-bar mechanism based on dynamic modeling, the system comprising: The ladder four-bar linkage mechanism optimization system based on dynamic modeling analysis runs in any computing device of a desktop computer, a notebook computer or a cloud data center, and the computing device includes a processor, a memory and a computer program stored in the memory and running on the processor, and the processor implements the steps in the ladder four-bar linkage mechanism optimization method based on dynamic modeling analysis in any one of claims 1-8 when executing the computer program.

10. An electronic device, comprising: At least one processor; And a memory in communication connection with the at least one processor; The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method of any one of claims 1-8.

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