Force closed-loop sliding mode control method for electronic mechanical braking system

Abstract

The invention discloses a force closed-loop sliding-mode control method for an electronic mechanical braking system, and relates to the technical field of an EMB system of an electric vehicle, and the method comprises the steps: building a motor model according to the basic characteristics of a motor under a rotor synchronous coordinate system; and based on a novel power exponent reaching law, force closed-loop sliding mode control of the electronic mechanical braking system is constructed according to a motor model and a relational expression between clamping force and friction plate displacement. By designing the force closed-loop sliding mode control power exponent reaching law, the clamping force is controlled in real time, and the problems that under the condition that other coefficients of an existing sliding mode control reaching law are the same, the reaching speed of a state variable to a sliding mode surface s = 0 is low, and buffeting can be generated are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle EMB systems, and in particular to a force closed-loop sliding mode control method for an electromechanical braking system. Background Art

[0002] Electromechanical Braking (EMB) is an advanced braking system that combines electronic control technology with traditional mechanical braking. With the continuous improvement of requirements for safety, response speed, and control accuracy in fields such as automobiles, aviation, and rail transit, traditional hydraulic or pneumatic braking systems have gradually revealed their deficiencies in terms of response speed, maintenance complexity, and environmental adaptability. The EMB system controls the operation of the brake through electronic signals, replacing the hydraulic pipeline, greatly reducing mechanical friction and hysteresis, and improving the braking efficiency and response speed. In addition, EMB can achieve more precise braking force distribution and dynamic adjustment through an intelligent control system, enhancing the overall driving safety and comfort. Driven by the trend of green environmental protection and electrification, EMB has gradually become one of the core technologies for future autonomous driving and new energy vehicle braking systems.

[0003] However, in actual braking conditions, for force closed-loop, if simple PI control is adopted, due to the jitter of the brake disc and the existence of thickness differences in the brake disc, the braking pressure measured by the pressure sensor will fluctuate, and it is impossible to accurately track the target clamping force. To address this problem, a force closed-loop sliding mode control is designed. Through the "switching" property of sliding mode control, the influence of the outside world on the braking pressure can be greatly reduced. However, for the existing Exponential Reaching Law (ERL), when the state variable reaches the sliding mode surface s = 0, its chattering will always exist, causing the actual clamping force to continuously vary along the target clamping force.

[0004] In order to avoid the actual clamping force of the EMB system force closed-loop sliding mode control from continuously fluctuating up and down along the target clamping force, how to improve the existing Exponential Reaching Law (ERL) and design a new reaching law is an urgent problem to be solved. Summary of the Invention

[0005] In order to overcome the defects in the above-mentioned prior art, the present invention provides a force closed-loop sliding mode control method for an electromechanical braking system, which is used to solve the problem that the actual clamping force tracking speed of the Exponential Reaching Law (ERL) of the EMB system force closed-loop sliding mode control is slow, and the problem that after the actual clamping force tracks the target clamping force, due to the nature of the sliding mode control algorithm itself, the actual clamping force will continuously chatter up and down near the target clamping force.

[0006] To achieve the above object, the present invention adopts the following technical solutions, including:

[0007] A force closed-loop sliding mode control method for an electromechanical braking system, including:

[0008] Determination of the motor model: In the rotor synchronous coordinate system, determine the mathematical model and torque equation of the motor;

[0009] Establishment of the force closed-loop sliding mode control of the electromechanical braking system: Based on the new power exponential reaching law, construct the force closed-loop sliding mode control of the electromechanical braking system according to the motor model and the relationship between the clamping force and the friction plate displacement.

[0010] Preferably, the determination of the motor model is specifically as follows:

[0011] Set the drive motor as a permanent magnet synchronous motor, and adopt the control strategy of d-axis current i d = 0;

[0012] The electromagnetic torque equation of the permanent magnet synchronous motor is

[0013] In the formula, T e represents the electromagnetic torque of the motor, P n is the number of pole pairs of the motor, ψ f represents the magnetic flux of the motor, i q represents the magnitude of the q-axis current of the motor;

[0014] The torque balance equation of the permanent magnet synchronous motor is

[0015] In the formula, J represents the moment of inertia of the motor; ω m represents the angular velocity of the motor, represents the derivative of the angular velocity of the motor rotor with respect to time; T L represents the load torque, and B represents the damping coefficient.

[0016] Preferably, the establishment of the force closed-loop sliding mode control of the electromechanical braking system is specifically as follows:

[0017] S21, select state variables:

[0018]

[0019] In the formula, x1 and x2 represent the selected state variables; is the differential of the state variable x1; F tar represents the target clamping force calculated under the braking condition, represents the differential of the target clamping force; F cl represents the actual clamping force, Denote the differential of the actual clamping force;

[0020] S22. Under the actual braking condition, when the brake disc contacts the friction plate, the relationship between the clamping force and the displacement of the friction plate is:

[0021]

[0022] In the formula, k s is the linear relationship coefficient after fitting the true clamping force F cl and the displacement x of the friction plate EMA , and D is the initial braking clearance;

[0023] S23. During the braking process, according to the lead L0 of the ball screw and the planetary gear reduction ratio i g , express the displacement x of the friction plate EMA as a relationship with the motor rotation angle θ m :

[0024] At the same time, obtain the relationship between the external load torque on the motor and the clamping force:

[0025] S24. Combine the above relationships with to specify the expression of the state variable as:

[0026]

[0027] In the formula, is the differential of the state variable x2, denotes differential, ω m denotes the angular velocity of the motor, T L denotes the load torque, B denotes the damping coefficient, T e denotes the electromagnetic torque of the motor;

[0028] S25. To achieve the tracking of the actual clamping force F cl to the target clamping force F tar , construct a sliding mode surface s and take the derivative of the sliding mode surface s to obtain In the formula, c is the coefficient of the state variable x1, denotes the differential of the sliding mode surface variable s;

[0029] S26. Design a power-law exponential reaching law PERL:

[0030] In the formula, k i > 0, 0 < δ 0i < 1, p i > 0, αi > 0, 0 < β < 1;

[0031] N i (s) represents the adjustment function of the power exponent reaching law PERL sliding mode surface s; δ 0i represents N i (s)'s adjustment coefficient; α i represents N i (s)'s proportionality coefficient of the exponential term of e; p i represents N i (s)'s exponential coefficient of the exponential term of e; k i represents the proportional term of the sliding mode surface function of the power exponent reaching law PERL; β represents the exponential coefficient of the sliding mode surface function of the power exponent reaching law PERL;

[0032] S27, for the power exponent reaching law, select the Lyapunov function, specifically V represents the selected Lyapunov function;

[0033] Taking the derivative of V gives That is, the designed power exponent reaching law satisfies the Lyapunov theorem, and the system state variables will converge to the sliding mode surface s = 0.

[0034] Preferably, it also includes the requirements for the sliding mode control parameter configuration with a shorter convergence time:

[0035]

[0036] In the formula, t represents time.

[0037] Preferably, the requirements for the sliding mode control parameter configuration with a shorter convergence time are as follows:

[0038] S31, the existing exponential reaching law is:

[0039] In the formula, k > 0, 0 < δ0 < 1, p > 0, α > 0;

[0040] The time t for the state variables of the existing exponential reaching law to reach the sliding mode surface s = 0 r is:

[0041]

[0042] In the formula, s(0) represents the initial value of the sliding mode surface;

[0043] S32, assume that the time for the state variables of the power exponent reaching law to reach the sliding mode s = 0 is t ri , from the expression of the power exponent reaching law obtain Integrate both sides of it, with the time variable integrated from 0 to t ri , and the sliding mode surface variable integrated from the initial value s(0) of the sliding mode surface to 0, to obtain the time t when the state variable of the power exponent reaching law reaches the sliding mode s = 0 ri as follows:

[0044]

[0045] S33. For t < t ri and s < 0,

[0046] For t < t ri and s > 0,

[0047] Combining the two equations, we get

[0048] S34. Express the integral formula in the form of the Γ function:

[0049]

[0050] where,

[0051] S35. Using the properties of the Γ function, assuming:

[0052] we get

[0053] Combining the above equation, we get

[0054] S36. To prove that the time t ri when the state variable of the power exponent reaching law reaches the sliding mode surface s = 0 r is shorter than the reaching time t rdi of the exponential reaching law, let the predicted reaching time t

[0055] of the power exponent reaching law PERL be: ri < t rdi ;

[0056] S37. When α i satisfies , we get the value of k i as

[0057] S38. For the exponential reaching law, when its parameter is, the predicted reaching time when its state variable reaches the sliding mode surface s = 0 is and t rd <t r ;

[0058] When δ0 = δ 0i 、k = k i at this time,

[0059] S39, when that is, |s(0)| > (1 - β) -1 / β at this time, From t rd > t rdi , combined with t ri <t rdi and t rd <t r , we get t ri <t r .

[0060] The present invention also provides a readable storage medium, on which a computer program is stored, and when the computer program is executed, the force closed-loop sliding mode control method for an electro-mechanical braking system is implemented.

[0061] The present invention also provides an electronic device, which includes a processor, a memory, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the force closed-loop sliding mode control method for an electro-mechanical braking system is implemented.

[0062] The present invention also provides a computer program product, which includes a computer program / instructions, and when the computer program / instructions are executed by a processor, the force closed-loop sliding mode control method for an electro-mechanical braking system is implemented.

[0063] The advantages of the present invention are as follows:

[0064] (1) Compared with the prior art, the force closed-loop sliding mode control method for an electro-mechanical braking system based on a power-exponential reaching law in the present invention controls the clamping force in real time by designing a power-exponential reaching law for force closed-loop sliding mode control, and solves the problems that in the case of the same other coefficients, the approaching speed of the state variable to the sliding surface s = 0 is slow and chattering will occur in the existing sliding mode control reaching law.

[0065] (2) The Power Exponential Reaching Law (PERL) designed in the present invention is an improvement based on the existing Exponential Reaching Law (ERL). Through derivation and calculation, the parameter configuration range of PERL that enables the actual clamping force to approach the target clamping force in a shorter time is obtained. At the same time, through analysis and verification, it is found that PERL has less chattering than ERL when the sliding mode surface variable reaches s = 0.

[0066] (3) By designing the Power Exponential Reaching Law (PERL), the present invention solves the problem that the existing Exponential Reaching Law (ERL) has a slow speed in making the actual clamping force track the target clamping force under the condition that other coefficients are the same. At the same time, it can also make the chattering amplitude of the actual clamping force smaller when the actual clamping force tracks the target clamping force, enabling the EMB system to have better braking performance. Description of the Drawings

[0067] Figure 1 It is the flowchart of the method of the present invention.

[0068] Figure 2 It is the comparison chart of the response speed of the sliding mode control algorithm before and after improvement.

[0069] Figure 3 It is under Figure 2 working conditions, the variation of the q-axis current of the permanent magnet synchronous motor adopting the Power Exponential Reaching Law (PERL) of the present invention.

[0070] Figure 4 It is under Figure 2 working conditions, the variation of the q-axis current of the permanent magnet synchronous motor adopting the existing Exponential Reaching Law (ERL). Detailed Embodiment

[0071] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0072] As shown by Figure 1 , this embodiment provides a force-closed-loop sliding mode control method for an electro-mechanical braking system based on a new Power Exponential Reaching Law (PERL), including the following steps:

[0073] First step, in order to derive and establish the sliding mode control algorithm for the EMB system, it is necessary to first clarify the mathematical model of the drive motor and the torque balance equation: in the rotor synchronous coordinate system, determine the mathematical model of the motor and the motor torque balance equation according to the basic characteristics of the motor and the characteristics and control methods of the selected drive motor.

[0074] S11, set the drive motor as a permanent magnet synchronous motor and adopt the control strategy of d-axis current i d = 0.

[0075] S12, the electromagnetic torque equation of the permanent magnet synchronous motor is:

[0076] In the formula, T e represents the electromagnetic torque of the motor, p n is the number of pole pairs of the motor, ψ f represents the magnetic flux of the motor, i q represents the magnitude of the q-axis current of the motor.

[0077] S13, the torque balance equation of the permanent magnet synchronous motor is:

[0078] In the formula, J represents the moment of inertia of the motor; ω m represents the angular velocity of the motor, represents the derivative of the angular velocity of the motor rotor with respect to time; T L represents the load torque, and B represents the damping coefficient.

[0079] Second step, fit to obtain the linear approximation relationship between the displacement of the friction plate pressing caliper and the clamping force generated by the extrusion of the caliper, and establish the force closed-loop sliding mode control of the electromechanical braking system by designing a power exponential reaching law: construct the force closed-loop sliding mode control of the electromechanical braking system according to the established permanent magnet synchronous motor model and the approximate relationship between the caliper clamping force and the friction plate displacement, and design a power exponential reaching law.

[0080] S21, first select the state variables:

[0081]

[0082] In the formula, x1 and x2 represent the selected state variables, is the differential of the state variable x1; F tar represents the target clamping force calculated by the ECU (electronic control unit) under the braking condition, represents the differential of the target clamping force; F cl represents the actual clamping force, represents the differential of the actual clamping force.

[0083] S22. When the brake disc contacts the friction plate under actual braking conditions, the clamping force and the displacement of the friction plate approximately show a linear relationship:

[0084]

[0085] In the formula, k s is the linear relationship coefficient after fitting of the true clamping force F cl and the displacement x EMA of the friction plate, and D is the initial braking clearance.

[0086] S23. During the braking process, according to the lead L0 of the ball screw and the planetary gear reduction ratio i g , the displacement x EMA of the friction plate can be expressed as a relational expression of the motor rotation angle θ m :

[0087]

[0088] Meanwhile, the relationship between the external load torque on the motor and the clamping force can be obtained:

[0089]

[0090] S24. Combining the above relational expressions and can concretize the expression of the state variable as:

[0091]

[0092] In the formula, is the differential of the state variable x2, represents differential, ω m represents the angular velocity of the motor, T L represents the load torque, B represents the damping coefficient, and T e represents the electromagnetic torque of the motor.

[0093] S25. To achieve the tracking of the actual clamping force F cl to the target clamping force F tar , a sliding mode surface s is constructed and its derivative is obtained to get In the formula, c is the coefficient of the state variable x1, represents the differential of the sliding mode surface variable s.

[0094] S26. During the application of the clamping force, in order to suppress the chattering of the state variable on the sliding mode surface and make the state variable reach the sliding mode surface faster, based on the existing Exponential Reaching Law (ERL), a new Power Exponential Reaching Law (PERL) is designed here.

[0095] The existing Exponential Reaching Law (ERL) is as follows:

[0096]

[0097] In the formula, s represents the sliding mode surface, k > 0, 0 < δ0 < 1, p > 0, α > 0;

[0098] N(s) represents the adjustment function of the sliding mode surface s of the Exponential Reaching Law ERL; α represents the proportional coefficient of the exponential term of e in N(s); δ0 represents the adjustment coefficient of N(s); p represents the exponential coefficient of the exponential term of e in N(s); k represents the proportional term of the sliding mode surface function of the Exponential Reaching Law ERL.

[0099] The new Power Exponential Reaching Law (PERL) is as follows:

[0100]

[0101] In the formula, k i > 0, 0 < δ 0i < 1, p i > 0, α i > 0, 0 < β < 1;

[0102] N i (s) represents the adjustment function of the sliding mode surface s of the Power Exponential Reaching Law PERL; δ 0i represents the adjustment coefficient of N i (s); α i represents the proportional coefficient of the exponential term of e in N i (s); p i represents the exponential coefficient of the exponential term of e in N i (s); k i represents the proportional term of the sliding mode surface function of the Power Exponential Reaching Law PERL; β represents the exponential coefficient of the sliding mode surface function of the Power Exponential Reaching Law PERL.

[0103] S27. For the Power Exponential Reaching Law, select the Lyapunov function, specifically Let \(V\) denote the selected Lyapunov function;

[0104] Taking the derivative of \(V\) gives That is, the designed power - exponential reaching law satisfies the Lyapunov theorem, and the system state variables will converge to the sliding surface \(s = 0\).

[0105] Step 3, Requirements for configuring sliding - mode control parameters with shorter convergence time: Under the vehicle braking condition, the ECU receives the signal that the brake pedal is depressed and calculates the required target clamping force \(F\) in combination with the degree to which the brake pedal is depressed ref , At this time, the EMB system starts to work. The driving motor drives the ball screw to make the friction plate press against the brake disc to generate a clamping force. Compared with the convergence time of the existing exponential reaching law, the power - exponential reaching law proposed in the present invention has a shorter convergence time for the actual clamping force to reach the target clamping force under the configuration of appropriate sliding - mode control parameters.

[0106] S31, The time \(t\) for the state variable of the existing exponential reaching law ERL to reach the sliding surface \(s = 0\) r is:

[0107]

[0108] In the formula, \(s(0)\) represents the initial value of the sliding surface.

[0109] S32, Assume that the time for the state variable of the power - exponential reaching law to reach the sliding surface \(s = 0\) is \(t\) ri , From the expression of PERL we get Integrating both sides of it, with the time variable integrated from 0 to \(t\) ri , and the sliding - surface variable integrated from \(s(0)\) to 0, we get the time \(t\) for the state variable of the power - exponential reaching law PERL to reach the sliding surface \(s = 0\) ri is:

[0110]

[0111] S33, Assume that when \(t\lt t\) ri and \(s\lt0\)

[0112] Assume that when \(t\lt t\) ri and \(s\gt0\)

[0113] Combining the two formulas, we get

[0114] S34, The integral formula can be expressed in the form of the Γ function, that is:

[0115]

[0116] In the formula,

[0117] S35. By using the properties of the Γ function, Therefore, assume:

[0118] We obtain

[0119] Combining with the above formula, we get

[0120] S36. To prove that the time t for the state variable of the designed power exponent reaching law (PERL) to reach the sliding mode surface s = 0 ri is shorter than the reaching time t of the exponential reaching law (ERL), r let the predicted reaching time of the power exponent reaching law (PERL) be and there is t ri < t rdi .

[0121] S37. When α i satisfies at this time, the value of k i can be obtained under appropriate conditions as

[0122] S38. For the exponential reaching law (ERL), when its parameter the predicted reaching time for its state variable to reach the sliding mode surface s = 0 is and t rd < t r ;

[0123] When δ0 = δ 0i , k = k i at this time,

[0124] S39. When i.e., |s(0)| > (1 - β) -1 / β at this time, From t rd > t rdi , combining with t ri < t rdi and t rd < t r , we obtain t ri < t r , indicating that the convergence time of the power exponent reaching law designed by the present invention is shorter.

[0125] Step 4: Proof of the reduction of the clamping force chattering after reaching the sliding surface: During the actual braking of the vehicle, when the actual clamping force reaches the required target clamping force, through the verification of relevant numerical derivations, the chattering of the proposed new reaching law is smaller than that of the prior art.

[0126] S41. For the exponential reaching law ERL Its chattering amplitude ξ is constantly ξ = 2Tk when the sliding surface variable s tends to the sliding surface s = 0, where T represents the discrete sampling time corresponding to the ERL.

[0127] S42. Discretize the power-exponential reaching law PERL designed in the present invention using the forward Euler method to obtain where T i represents the discrete sampling time corresponding to the PERL, and s(t) and s(t + 1) represent the magnitudes of the sliding surface variable s at time t and time t + 1, respectively.

[0128] S43. The expression for the sliding surface variable s at time t + 1 is obtained as:

[0129]

[0130] S44. When the actual clamping force continuously tends to the target clamping force and the sliding surface variable s continuously approaches 0, for the analysis of the sliding mode chattering situation, s(t) can be divided into s(t) = 0 + and s(t) = 0 - in two cases:

[0131] When s(t) = 0 + then s(t + 1) = -T i k i |0 + | β sgn(0 + ) + 0 + ≈ 0;

[0132] When s(t) = 0 - then s(t + 1) = -T i k i |0 - | β sgn(0 - ) + 0 - ≈ 0.

[0133] S45. Thus, when the ECU receives the signal that the electric vehicle brake pedal is depressed, it will calculate the required target clamping force F tar , and at this time, the target clamping force F tar and the actual clamping force F measured by the sensor actThe difference is used as the input of the designed power exponent reaching law PERL force closed-loop sliding mode control module. Through the calculation of this module, the reference value i of the motor q-axis current is obtained q The controller drives the motor according to the q-axis current reference. Through the drive motor - planetary gear - ball screw, the conversion of rotational motion - linear motion is realized. Finally, the friction plate is pushed by the ball screw to press the brake disc, and the actual clamping force F with less chatter is continuously measured and feedback by the pressure sensor act .

[0134] Figure 2 、 Figure 3 、 Figure 4 shows the actual effect of the present invention Figure 2 represents the comparison chart of the response speed of the sliding mode control algorithm before and after improvement Figure 3 represents at Figure 2 working conditions, the change of the q-axis current of the permanent magnet synchronous motor using the power exponent reaching law PERL Figure 4 represents at Figure 2 working conditions, the change of the q-axis current of the permanent magnet synchronous motor using the exponential reaching law ERL. Under the control requirement of a target step clamping force of 20 kN, while keeping the parameters of the two reaching laws δ0 = δ 0i 、k = k i and when the parameters of the power exponent reaching law PERL are in accordance with the requirements described in the specification, it can be obtained that the designed power exponent reaching law PERL of the present invention can make the actual clamping force reach the target clamping force faster, and after the actual clamping force reaches the target clamping force, the chatter of the magnitude of the q-axis current of the permanent magnet synchronous motor under the control of the power exponent reaching law PERL will be smaller than that of the existing exponential reaching law ERL

[0135] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention

Claims

1. A closed-loop sliding mode control method for an electromechanical brake system, characterized in that: include: Determination of the motor model: Determine the mathematical model and torque equation of the motor in the rotor synchronous coordinate system; Establishment of force closed-loop sliding mode control of electronic mechanical brake system: Based on the new power exponential reaching law, according to the motor model and the relationship between clamping force and friction plate displacement, the force closed-loop sliding mode control of electronic mechanical brake system is constructed.

2. The closed-loop sliding mode control method for an electronic mechanical brake system according to claim 1, characterized in that: The motor model is determined as follows: The drive motor is set to a permanent magnet synchronous motor, using the d-axis current i d =0 control strategy; The electromagnetic torque equation of permanent magnet synchronous motor is Where, T e Represents the electromagnetic torque of the motor, P n is the number of motor pole pairs, ψ f represents the motor flux, i q Indicates the magnitude of the motor q-axis current; The torque balance equation of the permanent magnet synchronous motor is Where, J represents the rotational inertia of the motor; ω m represents the angular velocity of the motor, It represents the derivative of the motor rotor angular velocity with respect to time; T L represents the load moment and B represents the damping coefficient.

3. The closed-loop sliding mode control method for an electronic mechanical brake system according to claim 1 or 2, characterized in that: The establishment of the force closed-loop sliding mode control of the electromechanical brake system is as follows: S21, select state variables: In the formula, x1 and x2 represent the selected state variables; is the differential of the state variable x1; F tar represents the target clamping force calculated under braking conditions, Represents the differential of the target clamping force; F cl Indicates the actual clamping force, Represents the differential of the actual clamping force; S22, under actual braking conditions, when the brake disc contacts the friction plate, the relationship between the clamping force and the displacement of the friction plate is: In the formula, k s is the actual clamping force F cl Displacement of friction plate x EMA The linear relationship coefficient after fitting, D is the initial brake clearance; S23, during the braking process, according to the lead L0 of the ball screw and the reduction ratio i of the planetary gear g , displace the friction plate by x EMA Expressed as the motor angle θ m The relationship is: At the same time, the relationship between the external load torque and clamping force on the motor is obtained: S24, combined with the above relationship and The expression of the state variable is concretely defined as: In the formula, is the differential of the state variable x2, express The differential of m represents the angular velocity of the motor, T L represents the load moment, B represents the damping coefficient, T e Represents the electromagnetic torque of the motor; S25, in order to achieve the actual clamping force F cl Target clamping force F tar Tracking, constructing the sliding surface s, and taking the derivative of the sliding surface s, we get Where c is the coefficient of the state variable x1, represents the differential of the sliding surface variable s; S26, design power exponential reaching law PERL: In the formula, k i >0,0<δ 0i <1, p i >0,α i >0, 0<β<1; N i (s) represents the regulating function of the power exponential reaching law PERL sliding surface s; δ 0i Represents the adjustment coefficient of Ni(s); α i N i (s) is the proportionality coefficient of the exponential term of e; p i N i (s) The exponential coefficient of the exponential term of e; k i represents the proportional term of the sliding surface function of the power exponential reaching law PERL; β represents the exponential coefficient of the sliding surface function of the power exponential reaching law PERL; S27, for the exponential approach law, the Lyapunov function is selected, specifically: V represents the selected Lyapunov function; Taking the derivative of V we get That is, the designed power exponential reaching law satisfies the Lyapunov theorem, and the system state variables will converge to the sliding surface s=0.

4. The closed-loop sliding mode control method for an electronic mechanical brake system according to claim 3, characterized in that: It also includes the sliding mode control parameter configuration requirements for shorter convergence time: In the formula, t represents time.

5. The closed-loop sliding mode control method for an electronic mechanical brake system according to claim 4, characterized in that: The sliding mode control parameter configuration requirements for shorter convergence time are as follows: S31, the existing exponential convergence law is: In the formula, k>0, 0<δ0<1, p>0, α>0; The time t when the existing exponential reaching law state variable reaches the sliding surface s = 0 r for: Where s(0) represents the initial value of the sliding surface; S32, assuming that the time when the exponential reaching law state variable reaches the sliding mode s = 0 is t ri , according to the expression of the power exponential reaching law get Integrate both sides of it, and integrate the time variable from 0 to t ri , the sliding surface variable is integrated from the initial value s(0) of the sliding surface to 0, and the time t when the state variable of the power exponential reaching law reaches the sliding mode s=0 is obtained ri for: S33, for t<t ri When s<0, For t<t ri When s>0, Combining the two equations, we get S34, the integral Expressed as a Γ function: In the formula, S35, using the properties of the Γ function, Assumptions: get Combining the above formula, we can get S36, in order to prove that the exponential reaching law state variable reaches the sliding surface s = 0 time t ri The arrival time t of the exponential reaching law r short, assuming that the estimated arrival time t of the power exponential reaching law PERL rdi for: And there is t ri <t rdi ; S37, when α i satisfy hour, Get k i The value of S38, for the exponential reaching law, when its parameter When , the estimated time for its state variable to reach the sliding surface s=0 is And t rd <t r ; When δ0=δ 0i , k=k i hour, S39, when That is, |s(0)|>(1-β) -1 / β hour, By rd >t rdi , combined with t ri <t rdi and t rd <t r , we get t ri <t r .

6. A readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the force closed-loop sliding mode control method of an electronic mechanical brake system as described in any one of claims 1-5 is implemented.

7. An electronic device, characterized in that: It includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a force closed-loop sliding mode control method for an electronic mechanical brake system as described in any one of claims 1-5.

8. A computer program product, characterized in that It includes a computer program / instruction, which, when executed by a processor, implements a force closed-loop sliding mode control method for an electronic mechanical brake system as described in any one of claims 1-5.

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