Method, device, and storage medium for determining the relationship between motor torque and motor speed

Abstract

The present invention proposes a method, device, storage medium and terminal for determining the relationship between motor torque and motor speed, wherein the method includes: determining the initial relationship between the motor torque and the motor speed; determining the equivalent conversion inertia of the motor according to the inertia equivalent conversion method; determining the first motion relationship between the effective output torque and angular acceleration of the motor within a preset time, and the second motion relationship between the master cylinder displacement and angular displacement within a preset time according to the initial relationship and the equivalent conversion inertia; determining the optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship; determining the target relationship between the motor torque and the motor speed according to the optimization model. The method described in the present invention designs a reliable and effective relationship between motor torque and motor speed to meet the needs of automotive wire control and intelligent braking, greatly shortening development time and development costs.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile braking systems, and in particular to a method, a device, a storage medium and a terminal for determining the relationship between motor torque and motor speed. Background Art

[0002] With the continuous development of electrification and intelligence of new energy vehicles, the hydraulic braking system of traditional vehicles is that the driver applies braking pressure to the wheel cylinder of each wheel brake by stepping on the brake pedal to achieve braking and slow down the vehicle, which does not meet the braking requirements of automobile wire control and intelligence. Instead, electro-hydraulic braking systems continue to emerge. The basic principle of some new electro-hydraulic braking systems is to obtain the pedal displacement signal system and rely on the motor to provide a certain proportion of motor assistance. Therefore, how to formulate the motor torque and motor speed relationship (TN) curve determines the safety and performance of the braking system, which is the core technology of the electro-hydraulic braking system. Domestic Bosch motor manufacturers and suppliers often have to input the motor torque and motor speed relationship curve in the early stage of design.

[0003] At the same time, the relationship curve between the motor torque and motor speed of the motor is related to many factors such as the brake pads and brakes of the basic braking system of the vehicle. Electromagnetic simulation realizes the simulation of these physical quantities, which makes its calculation too complicated and does not intuitively reflect the impact of changes on which physical quantity. In addition, as a high-threshold industry technology, domestic companies do not have the R&D capabilities in the early stage of electro-hydraulic brake system design, and spend a huge amount of money to repeatedly modify the design parameters in the later stage, resulting in high design and development costs. Once the designed motor TN curve does not meet the actual use requirements, the motor covers a limited number of vehicle models, the motor manufacturing cost is too high, and the product verification cost is too high.

[0004] Therefore, how to provide a simple and effective design method for the TN curve of the electro-hydraulic brake system has become an urgent need in the field of wire control braking. Summary of the invention

[0005] In order to solve at least one of the above technical problems, the present invention proposes a method, device, storage medium and terminal for determining the relationship between motor torque and motor speed. The present invention is specifically implemented by the following technical solutions:

[0006] A first aspect of the present invention provides a method for determining a relationship between motor torque and motor speed, the method comprising:

[0007] Determining an initial relationship between the motor torque and the motor speed;

[0008] According to the inertia equivalent conversion method, determine the equivalent conversion inertia of the motor;

[0009] Determining, based on the initial relationship and the equivalent conversion inertia, a first motion relationship between the effective output torque and angular acceleration of the motor within a preset time, and a second motion relationship between the displacement and angular displacement of the master cylinder within a preset time;

[0010] Determining an optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship;

[0011] According to the optimization model, the initial relationship between the motor torque and the motor speed is optimized to determine a target relationship between the motor torque and the motor speed.

[0012] In some possible implementations, the effective output torque is the difference between the output torque of the motor and the resistance torque.

[0013] In some possible implementations, the resistance torque is determined according to a master cylinder pressure, and the master cylinder pressure is determined according to a master cylinder stroke.

[0014] In some possible implementations, determining the motor equivalent conversion inertia according to the inertia equivalent conversion method includes:

[0015] The components of the transmission system are converted to the motor end according to the preset transmission ratio value to determine the equivalent conversion inertia of the motor.

[0016] In some possible implementations, the first motion relationship and the second motion relationship are determined by the following formula:

[0017]

[0018] Among them, J e is the equivalent moment of inertia, ω k is the angular velocity at the kth moment, α k is the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism.

[0019] In some possible implementations, optimizing the initial relationship between the motor torque and the motor speed according to the optimization model to determine a target relationship between the motor torque and the motor speed includes:

[0020] Calculating the pressure building time of the optimization model within a preset time step;

[0021] If the pressure building time is less than the preset pressure building time and meets the preset conditions, the target relationship between the motor torque and the motor speed is determined according to the pressure building time.

[0022] A second aspect of the present invention provides a device for determining the relationship between motor torque and motor speed, the device comprising:

[0023] An initial relationship determination module, used to determine an initial relationship between the motor torque and the motor speed;

[0024] An equivalent conversion inertia determination module is used to determine the equivalent conversion inertia of the motor according to an inertia equivalent conversion method;

[0025] a motion relationship determination module, for determining a first motion relationship between an effective output torque and an angular acceleration of the motor within a preset time, and a second motion relationship between a master cylinder displacement and an angular displacement within a preset time according to the initial relationship and an equivalent conversion inertia of the motor;

[0026] An optimization model determination module, configured to determine an optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship;

[0027] The torque and speed target relationship determination module is used to optimize the initial relationship between the motor torque and the motor speed according to the optimization model to determine the target relationship between the motor torque and the motor speed.

[0028] The present invention also provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for determining the relationship between the motor torque and the motor speed as described above is implemented.

[0029] The present invention also provides a terminal, comprising one or more processors and a memory. The memory is coupled to the processor and is used to store one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method for determining the relationship between the motor torque and the motor speed.

[0030] By adopting the above technical solution, the method, device, storage medium and terminal for determining the relationship between motor torque and motor speed of the present invention have the following beneficial effects:

[0031] This method covers the electro-hydraulic brake system. By establishing a multi-parameter and multi-variable mathematical model, a reliable and effective motor torque and motor speed relationship (TN) curve is designed to meet the needs of automotive wire control and intelligent braking, greatly shortening the development time and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A flow chart of a method for determining the relationship between motor torque and motor speed provided by an embodiment of the present invention;

[0034] Figure 2 A structural relationship diagram of a motion physical model of an electro-hydraulic brake system provided in an embodiment of the present invention;

[0035] Figure 3 A flow chart of a method for determining the relationship between motor torque and motor speed provided by another embodiment of the present invention;

[0036] Figure 4 3 curve diagrams of the initial relationship between motor torque and motor speed provided in the embodiments of the present invention;

[0037] Figure 5 The voltage build-up curves corresponding to the three initial relationships between motor torque and motor speed provided in the embodiments of the present invention;

[0038] Figure 6 A structural diagram of a device for determining the relationship between motor torque and motor speed provided by an embodiment of the present invention;

[0039] Figure 7 A schematic diagram of the structure of a computer terminal device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] In several embodiments provided in this application, the described system embodiments are only schematic, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation, for example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection of modules or units, which may be electrical or other forms.

[0042] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0043] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0044] The present invention provides a method for determining the relationship between motor torque and motor speed. Figure 1 As shown, the method includes:

[0045] S101, determining an initial relationship between the motor torque and the motor speed;

[0046] Determine the initial relationship curve between the initial motor torque and the motor speed, and set the h key node data on the curve as (T mh ,N mh ), and fit it with a multi-order equation function:

[0047]

[0048] Among them, T m is the motor stall torque, N me is the rated speed of the motor, b n It is the constant term of the multi-time function of the fitting curve segment. By setting several key point data, the initial relationship curve of the complete motor torque and motor speed is preliminarily determined, so as to optimize the relationship between the motor torque and motor speed in the later stage.

[0049] S102, determining the equivalent conversion inertia of the motor according to an inertia equivalent conversion method;

[0050] Use the inertia equivalent conversion method to establish the equivalent conversion inertia of the motor. The transmission forms of the electro-hydraulic brake system are mostly ball screw, worm gear and rack and pinion transmission. Based on the internal one-stage or multi-stage transmission ratio, the n components of the transmission system can be equivalent to the motor end according to the transmission ratio i to establish the motor equivalent rotational inertia J e :

[0051] J e =J m +f(i1)J1+f(i1)J2+......+f(i n )J n

[0052] f(i n ) is the transmission ratio of the nth component.

[0053] S103, determining a first motion relationship between the effective output torque and angular acceleration of the motor within a preset time, and a second motion relationship between the master cylinder displacement and angular displacement within a preset time according to the initial relationship and the equivalent conversion inertia;

[0054] From the perspective of function and structure, the electro-hydraulic brake system can be divided into motor, transmission mechanism and brake master cylinder, separate or valve block functional components, such as Figure 2 As shown, the brake master cylinder pressure is transmitted to the motor end through the transmission mechanism, and the motor resistance torque is output. The transmission mechanism can be a ball screw, a worm gear, a gear rack or a gear transmission in one or more stages.

[0055] Establish the motor motion relationship equation from the motion physics model: Starting from the perspective of the shortest motor pressure build-up time, within a small time period t, the motor can be considered to be uniformly accelerated linear motion. Based on the working principle of the electro-hydraulic brake system, that is, there is a force and motion relationship transmission between the motor, transmission system, and master cylinder, the motor's output torque T mk , wheel cylinder pressure to motor resistance torque T rk , master cylinder displacement s k Equivalent moment of inertia of the motor J e , angular velocity ω k , angular displacement θ k At the kth moment, there is a motion relationship equation within the smaller time period t, which includes the first motion relationship between the effective output torque and angular acceleration of the motor within the preset time, and the second motion relationship between the displacement and angular displacement of the master cylinder within the preset time. The formula is as follows:

[0056]

[0057] Among them, J e is the equivalent moment of inertia, ω k is the angular velocity at the kth moment, α kis the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism.

[0058] By equivalently converting the product of inertia and angular acceleration, the output torque T of the motor mk And wheel cylinder pressure to motor resistance torque T rk The difference between the two and the effective motor output torque T e The equivalent relationship between them determines the angular acceleration α of the motor at time k k ; Angular velocity ω at time k k , angular acceleration α k And time t determines the angular velocity ω at the next moment, i.e., time t+1 k+1 ; through the angular displacement θ at time k k , angular velocity ω k , angular velocity ω at time k+1 k+1 Determine the angular displacement θ at time k+1 k+1 ; Through the transmission ratio h(i) and angular displacement θ of the transmission mechanism k Determine the master cylinder displacement s corresponding to the angle the motor rotates from 0 to this moment k The master cylinder stroke is determined according to the master cylinder displacement, and the master cylinder pressure is determined according to the relationship between the master cylinder stroke and the master cylinder pressure. The physical model motion is converted into numerical analysis and calculation, and numerical calculation can be performed when fewer parameters are known.

[0059] The brake master cylinder pressure is transmitted to the motor end through the transmission mechanism, generating motor resistance torque T rk , the formula is as follows:

[0060] T rk =P k S M H(M)

[0061] Among them, p k is the master cylinder pressure at time k, S M is the master cylinder stroke, and H(M) is the transmission system output force (brake master cylinder end) and input torque (motor end) transmission function equation.

[0062] The transmission mechanism can be a ball screw, a worm gear, a gear rack or a gear transmission in one or more stages. Therefore, different transmission forms correspond to different transmission relationship equations, and the method of the present invention can be applicable to all of them.

[0063] S104, determining an optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship;

[0064] There is a one-to-one correspondence between the pressure value of the electro-hydraulic brake system and the motor angle, that is, when the motor angle reaches the maximum angle θ m At this time, the motor can output the maximum design brake pressure Pmax. Therefore, with the shortest vehicle maximum pressure build-up time as the goal, the motor torque and motor speed relationship (TN) characteristic optimization design curve based on the motor rotation angle θ is established. The motor starts from the minimum rotation angle 0 to the maximum rotation angle θ m The shortest used time and the shortest maximum voltage build-up time indicate that the higher the performance of the motor TN characteristic curve, the better the relationship between the motor torque and the motor speed. The established optimization model of the relationship between the motor torque and the motor speed is as follows:

[0065]

[0066] Among them, j(t) is the voltage build-up time, J(θ) is the motor angle under a specific TN curve, and the movement process of the motor angle J(θ) under different TN characteristic curves is also different. k is the time, T mk and T rk is the optimization parameter, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, G(T mk ,N mk ) is based on the above steps to T mk and T rk The function to be optimized.

[0067] With the goal of minimizing the vehicle's maximum pressure build-up time j(t), an optimization design curve of the motor torque and motor speed relationship (TN) based on the motor angle is established.

[0068] Convert physical model motion into numerical analysis calculations to reduce test equipment procurement and R&D costs and shorten R&D cycles.

[0069] S105 . Optimize the initial relationship between the motor torque and the motor speed according to the optimization model to determine a target relationship between the motor torque and the motor speed.

[0070] like Figure 3As shown, in one embodiment, the PV characteristic curve of a certain vehicle model tested in real vehicle is used to establish the fitting equation of the master cylinder stroke and brake pressure curve:

[0071]

[0072] Set the initial TN relationship curve at a certain temperature: set the vehicle braking demand motor stall torque to 4.25N·m, and refer to the empirical value of the motor rated speed to 1200rpm.

[0073] Based on the characteristics of brushless motors, the entire working process of brushless motors is divided into constant torque section and constant power section. In the constant torque section, when the motor speed increases to the rated speed of 1200rpm, the motor torque always outputs a stall torque of 4.25N·m; in the constant power section, as the motor speed increases, the motor torque decreases accordingly. Three different curves are set, such as Figure 4 As shown in Table 1, three curve equations were obtained by fitting multiple equations:

[0074] Table 1 sets three TN curve equations

[0075]

[0076]

[0077] Substitute into the following TN curve equation:

[0078]

[0079] Then, the equivalent moment of inertia of the motor is established using the inertia equivalent conversion method, as shown in Table 2. The transmission system of the electro-hydraulic brake is set to a primary ball screw transmission, and the motor rotor is directly connected to the ball screw component. The equivalent moment of inertia of the motor is the sum of the moment of inertia of the screw component and the moment of inertia of the motor, and the screw lead is set to 3 mm.

[0080] Table 2 Motor equivalent moment of inertia kg·m

[0081]

[0082] The motor motion relationship equation is established. The motion relationship equation includes the first motion relationship between the effective output torque and angular acceleration of the motor within the preset time, and the second motion relationship between the displacement of the master cylinder and the angular displacement within the preset time. From the perspective of the shortest motor pressure building time, a smaller time t = 1ms is set. The motor can be considered to be uniformly accelerated linear motion. Based on the working principle of the electro-hydraulic brake system, that is, there is a force and motion relationship transmission between the motor, the transmission system, and the master cylinder, the output torque T of the motor is mk , wheel cylinder pressure to motor resistance torque T rk , master cylinder displacement sk Equivalent moment of inertia of the motor J e , angular velocity ω k , angular displacement θ k At the kth moment, within the smaller time period t, there exists a motion relationship equation:

[0083]

[0084] Among them, J e is the equivalent moment of inertia, ω k is the angular velocity at the kth moment, α k is the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism.

[0085] By equivalently converting the product of inertia and angular acceleration, the output torque T of the motor mk And wheel cylinder pressure to motor resistance torque T rk The difference between the two and the effective motor output torque T e The equivalent relationship between them determines the angular acceleration α of the motor at time k k ; Angular velocity ω at time k k , angular acceleration α k And time t determines the angular velocity ω at the next moment, i.e., time t+1 k+1 ; through the angular displacement θ at time k k , angular velocity ω k , angular velocity ω at time k+1 k+1 Determine the angular displacement θ at time k+1 k+1 ; Through the transmission ratio h(i) and angular displacement θ of the transmission mechanism k Determine the master cylinder displacement s corresponding to the angle the motor rotates from 0 to this moment k The master cylinder stroke is determined according to the master cylinder displacement, and the master cylinder pressure is determined according to the relationship between the master cylinder stroke and the master cylinder pressure. The physical model motion is converted into numerical analysis and calculation, and numerical calculation can be performed when fewer parameters are known.

[0086] The brake master cylinder pressure is transmitted to the motor end through the transmission mechanism, generating motor resistance torque T rk , the formula is as follows:

[0087] T rk=P K S M P h / 2πη

[0088] Among them, p k is the master cylinder pressure at time k, S M The stroke of the master cylinder is 23.81 mm, P h is the screw lead, the screw lead is 3mm, η is the screw transmission efficiency value, and the screw transmission efficiency is between 0.88 and 0.92.

[0089] There is a one-to-one correspondence between the pressure value of the electro-hydraulic brake system and the motor angle, that is, when the motor angle reaches the maximum angle θ m At this time, the motor can output the maximum design brake pressure Pmax. Therefore, with the shortest vehicle maximum pressure build-up time as the goal, the motor torque and motor speed relationship (TN) characteristic optimization design curve based on the motor rotation angle θ is established. The motor starts from the minimum rotation angle 0 to the maximum rotation angle θ m The shortest used time and the shortest maximum voltage build-up time indicate that the motor TN characteristic curve performance is higher, that is, the relationship between motor torque and motor speed is optimal.

[0090] Referring to the actual needs of passenger cars under 2.5t in the automotive industry, the maximum pressure of the vehicle can be set to 10MPa, corresponding to a pressure building time of less than 160ms. According to the formula, the relationship curve between the master cylinder stroke and the brake pressure is:

[0091]

[0092] We can know θ m =19.23πrad.

[0093] The optimization model of the relationship between motor torque and motor speed is established, and the formula is as follows:

[0094]

[0095] Among them, j(t) is the voltage build-up time, J(θ) is the motor angle under a specific TN curve, and the movement process of the motor angle J(θ) under different TN characteristic curves is also different. k is the time, T mk and T rk is the optimization parameter, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, G(T mk ,N mk ) is based on the above steps to T mk and T rk The function to be optimized.

[0096] With the goal of minimizing the vehicle's maximum pressure build-up time j(t), an optimization design curve of the motor torque and motor speed relationship (TN) based on the motor angle is established.

[0097] Convert physical model motion into numerical analysis calculations to reduce test equipment procurement and R&D costs and shorten R&D cycles.

[0098] In one embodiment, the effective output torque is the difference between the output torque of the motor and the resistance torque.

[0099] Effective motor output torque T e The calculation formula is as follows:

[0100] T e =T mk -T rk

[0101] Among them, T mk is the motor output torque, T rk is the resistance torque of the wheel cylinder pressure on the motor.

[0102] In one embodiment, the resistance torque is determined according to a master cylinder pressure, and the master cylinder pressure is determined according to a master cylinder stroke.

[0103] Specifically, the pressure (PV) characteristic curve is the relationship between the master cylinder stroke and the master cylinder pressure. The pressure will generate a resistance torque, which will eventually be fed back to the motor to affect the pressure building time. Input the pressure (PV) characteristic curve of the vehicle, select the vacuum booster system that is consistent with the cylinder diameter of the master cylinder of the electro-hydraulic brake system, set the relationship curve between the brake pressure and the pedal stroke under various working conditions such as full load and no load, and establish the PV characteristic curve (pressure characteristic curve) fitting equation of the vehicle's basic brake system. Usually, two curve equations can be set, one is a linear equation, and the other is fitted with a multi-function equation.

[0104]

[0105] By parameterizing the relationship curve between the master cylinder stroke and the master cylinder pressure of the whole vehicle, namely the PV curve, numerical calculations can be performed to avoid spending a lot of money on bench or vehicle testing, reduce the R&D cost of purchasing test equipment, shorten the R&D cycle, and at the same time provide feedback on the calculation results of the optimized PV curve.

[0106] In one embodiment, determining the equivalent converted inertia of the motor according to the inertia equivalent conversion method includes:

[0107] The components of the transmission system are converted to the motor end according to the preset transmission ratio value to determine the equivalent conversion inertia of the motor.

[0108] Use the inertia equivalent conversion method to establish the equivalent conversion inertia of the motor. The transmission system of the electro-hydraulic brake system is mostly a ball screw or worm gear transmission. Based on the internal one-stage or multi-stage transmission ratio, the n components of the transmission system can be equivalent to the motor end according to the transmission ratio i to establish the motor equivalent rotational inertia J e :

[0109] J e =J m +f(i1)J1+f(i1)J2+......+f(i n )J n

[0110] f(i n ) is the transmission ratio of the nth component.

[0111] In one embodiment, the transmission system includes a transmission mechanism, and the transmission mechanism includes a ball screw, a worm gear, or a rack and pinion.

[0112] From the perspective of function and structure, the electro-hydraulic brake system can be divided into motor, transmission mechanism and brake master cylinder (individual or valve block functional components). The transmission mechanism can be a ball screw, worm gear, rack and pinion or gear transmission in one or more stages.

[0113] In one embodiment, the first motion relationship and the second motion relationship are determined by the following formula:

[0114]

[0115] Among them, j(t) is the pressure building time, J e is the equivalent moment of inertia, ω k is the angular velocity at the kth moment, α k is the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism.

[0116] By equivalently converting the product of inertia and angular acceleration, the output torque T of the motor mk And wheel cylinder pressure to motor resistance torque T rk The difference between the two and the effective motor output torque T e The equivalent relationship between them determines the angular acceleration α of the motor at time k k; Angular velocity ω at time k k , angular acceleration α k And time t determines the angular velocity ω at the next moment, i.e., time t+1 k+1 ; through the angular displacement θ at time k k , angular velocity ω k , angular velocity ω at time k+1 k+1 Determine the angular displacement θ at time k+1 k+1 ; Through the transmission ratio h(i) and angular displacement θ of the transmission mechanism k Determine the master cylinder displacement s corresponding to the angle the motor rotates from 0 to this moment k The master cylinder stroke is determined according to the master cylinder displacement, and the master cylinder pressure is determined according to the relationship between the master cylinder stroke and the master cylinder pressure. The physical model motion is converted into numerical analysis and calculation, and numerical calculation can be performed when there are fewer known parameters.

[0117] In one embodiment, the optimizing the initial relationship between the motor torque and the motor speed according to the optimization model to determine the target relationship between the motor torque and the motor speed includes:

[0118] Calculating the pressure building time of the optimization model within a preset time step;

[0119] If the pressure building time is less than the preset pressure building time and meets the preset conditions, the target relationship between the motor torque and the motor speed is determined according to the pressure building time.

[0120] There is a one-to-one correspondence between the pressure value of the electro-hydraulic brake system and the motor angle, that is, when the motor angle reaches the maximum angle θ m At this time, the motor can output the maximum design brake pressure Pmax. Therefore, with the shortest vehicle maximum pressure build-up time as the goal, the motor torque and motor speed relationship (TN) characteristic optimization design curve based on the motor rotation angle θ is established. The motor starts from the minimum rotation angle 0 to the maximum rotation angle θ m The shortest used time and the shortest maximum voltage build-up time indicate that the motor TN characteristic curve performance is higher, that is, the relationship between motor torque and motor speed is optimal.

[0121] Referring to the actual needs of passenger cars under 2.5t in the automotive industry, the maximum braking pressure of the vehicle can be set to 10MPa, corresponding to a pressure building time of less than 160ms. According to the formula, the relationship curve between the master cylinder stroke and the master cylinder pressure is:

[0122]

[0123] We can know θ m =19.23πrad.

[0124] By converting the physical model into a mathematical formula, the motion relationship of the physical model can be converted into a mathematical formula for numerical analysis and calculation.

[0125] The optimization model of the relationship between motor torque and motor speed is established, and the formula is as follows:

[0126]

[0127] Among them, j(t) is the voltage build-up time, J(θ) is the motor angle under a specific TN curve, and the movement process of the motor angle J(θ) under different TN characteristic curves is also different. k is the time, T mk and T rk is the optimization parameter, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, G(T mk ,N mk ) is based on the above steps to T mk and T rk The function to be optimized.

[0128] With the goal of minimizing the vehicle's maximum pressure build-up time j(t), an optimization design curve of the motor torque and motor speed relationship (TN) based on the motor angle is established.

[0129] Convert physical model motion into numerical analysis and calculation, reduce test equipment procurement and R&D costs, and shorten R&D cycles

[0130] Numerical calculations were performed with a step size of t = 1 ms, and different pressure build-up times for the three curves were obtained, as shown in Table 3. The pressure build-up process is as follows: Figure 5 As shown in Table 3, 10MPa pressure build-up time

[0131]

[0132] From the data in Table 3, it can be seen that the pressure build-up time of 10MPa can be met at 160ms. There are two curves, namely curve 1 and curve 2. However, the pressure build-up time of curve 1 is 140ms, which is far beyond the design requirement and has a slightly lower performance. It is recommended to use the TN curve of curve 2, that is, to meet the pressure build-up time requirement under the PV characteristic curve of the whole vehicle.

[0133] See also Figure 6 The second aspect of the present invention provides a device for determining the relationship between motor torque and motor speed, the device comprising:

[0134] An initial relationship determination module 10, used to determine an initial relationship between the motor torque and the motor speed;

[0135] An equivalent conversion inertia determination module 20 is used to determine the equivalent conversion inertia of the motor according to an inertia equivalent conversion method;

[0136] A motion relationship determination module 30, for determining a first motion relationship between an effective output torque and an angular acceleration of the motor within a preset time, and a second motion relationship between a master cylinder displacement and an angular displacement within a preset time according to the initial relationship and the equivalent conversion inertia of the motor;

[0137] An optimization model determination module 40, configured to determine an optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship;

[0138] The torque and speed target relationship determination module 50 is used to optimize the initial relationship between the motor torque and the motor speed according to the optimization model to determine the target relationship between the motor torque and the motor speed.

[0139] The specific limitations on the device for determining the relationship between the motor torque and the motor speed can be found in the above-mentioned limitations, which will not be repeated here.

[0140] Each module in the above-mentioned device for determining the relationship between motor torque and motor speed can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0141] See also Figure 7 An embodiment of the present invention provides a terminal, comprising one or more processors and a memory. The memory is coupled to the processor and is used to store one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the relationship between the motor torque and the motor speed in any one of the above embodiments.

[0142] The processor is used to control the overall operation of the computer terminal device to complete all or part of the steps of the above-mentioned method for determining the relationship between the motor torque and the motor speed. The memory is used to store various types of data to support the operation of the computer terminal device, and these data may include, for example, instructions for any application or method used to operate on the computer terminal device, as well as application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Read-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0143] In an exemplary embodiment, the computer terminal device can be implemented by one or more application specific integrated circuits (Application Specific Integrated Circuit, ASC), digital signal processors (Digital Signal Processor, DSP), digital signal processing devices (Digital Signal Processing Device, DSPD), programmable logic devices (Programmable Logic Device, PLD), field programmable gate arrays (Field Programmable Gate Array, FPGA), controllers, microcontrollers, microprocessors or other electronic components to execute the above-mentioned method for determining the relationship between motor torque and motor speed, and achieve the same technical effect as the above-mentioned method.

[0144] In another exemplary embodiment, a storage medium including program instructions is also provided, and when the program instructions are executed by a processor, the steps of the method for determining the relationship between the motor torque and the motor speed in any of the above embodiments are implemented. For example, the storage medium can be the above-mentioned memory including program instructions, and the above-mentioned program instructions can be executed by the processor of the terminal to complete the above-mentioned method for determining the relationship between the motor torque and the motor speed, and achieve the technical effect consistent with the above-mentioned method.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining the relationship between motor torque and motor speed, characterized in that: The method comprises: Determining an initial relationship between the motor torque and the motor speed; According to the inertia equivalent rotation method, determine the equivalent rotation inertia of the motor; According to the initial relationship and the equivalent moment of inertia, a first motion relationship between the effective output torque and angular acceleration of the motor within a preset time, and a second motion relationship between the displacement of the master cylinder and the angular displacement within a preset time are determined; the first motion relationship and the second motion relationship are determined by the following formula: Among them, J e is the equivalent conversion inertia, ω k is the angular velocity at the kth moment, α k is the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism; According to the first motion relationship and the second motion relationship, an optimization model of the relationship between the motor torque and the motor speed is determined; the optimization model is determined by the following formula: Wherein, j(t) is the pressure build-up time, J(θ) is the motor angle under the TN characteristic curve, and the movement process of the motor angle J(θ) under different TN characteristic curves is also different, k is the time, G(T mk ,N mk ) is based on the above steps to T mk and T rk The optimized function; the TN characteristic curve is a curve established based on the relationship between the motor torque and the motor speed of the motor angle with the goal of minimizing the vehicle maximum pressure build-up time; Calculate the pressure building time of the optimization model within a preset time step; if the pressure building time is less than the preset pressure building time and meets the preset conditions, determine the target relationship between the motor torque and the motor speed according to the pressure building time.

2. The method according to claim 1, characterized in that The effective output torque is the difference between the output torque of the motor and the resistance torque.

3. The method according to claim 2, characterized in that The resistance torque is determined according to the master cylinder pressure, and the master cylinder pressure is determined according to the master cylinder stroke.

4. The method according to claim 1, characterized in that: Determining the equivalent conversion inertia of the motor according to the inertia equivalent conversion method includes: The components of the transmission system are converted to the motor end according to the preset transmission ratio value to determine the equivalent conversion inertia of the motor.

5. A device for determining the relationship between motor torque and motor speed, characterized in that: The device comprises: An initial relationship determination module, used to determine an initial relationship between the motor torque and the motor speed; An equivalent rotational inertia determination module is used to determine the equivalent rotational inertia of the motor according to an inertia equivalent rotation method; A motion relationship determination module is used to determine a first motion relationship between the effective output torque and angular acceleration of the motor within a preset time, and a second motion relationship between the master cylinder displacement and angular displacement within a preset time according to the initial relationship and the equivalent rotational inertia of the motor; the first motion relationship and the second motion relationship are determined by the following formula: Among them, ω k is the angular velocity at the kth moment, α k is the angular acceleration, T e is the effective motor output torque, T mk is the motor output torque, T rk is the wheel cylinder pressure to the motor resistance torque, ω k+1 is the angular velocity at the k+1th moment, t is the t time period at the kth moment, θ k is the angular displacement at the kth moment, θ k+1 is the angular displacement at the k+1th moment, s k The displacement of the master cylinder, h(i) is the transmission ratio of the transmission mechanism; The optimization model determination module is used to determine the optimization model of the relationship between the motor torque and the motor speed according to the first motion relationship and the second motion relationship; the optimization model is determined by the following formula: Wherein, j(t) is the pressure build-up time, J(θ) is the motor angle under the TN characteristic curve, and the movement process of the motor angle J(θ) under different TN characteristic curves is also different, k is the time, G(T mk ,N mk ) is based on the above steps to T mk and T rk The optimized function; the TN characteristic curve is a curve established based on the relationship between the motor torque and the motor speed of the motor angle with the goal of minimizing the vehicle maximum pressure build-up time; The module for determining the target relationship between torque and speed is used to calculate the pressure building time of the optimization model within a preset time step; if the pressure building time is less than the preset pressure building time and meets the preset conditions, the target relationship between the motor torque and the motor speed is determined according to the pressure building time.

6. A storage medium, characterized in that: The storage medium stores instructions, and when the instructions are executed by the processor, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A terminal, characterized in that: The method comprises a memory and a processor, wherein the memory stores instructions, and the processor loads the instructions to execute the steps of the method according to any one of claims 1 to 4.

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