Automobile tire burst safety protection method based on EPS

Abstract

The invention relates to the technical field of automobiles, in particular to an EPS (electric power steering)-based automobile tire burst safety protection method, which comprises the following steps that a signal processing unit acquires signals and calculates variable quantity, a tire burst working condition judging unit estimates transverse acceleration according to data of the signal processing unit, tire burst deflection quantity is obtained after integration, and the tire burst working condition is judged according to the judged automobile posture. And tire burst torque compensation is started, after compensation is started, basic compensation torque is calculated through steering wheel angle closed-loop PID control, and when the function relieving condition is met, tire burst protection function torque output is reduced or cut off. Compared with the prior art, by controlling the output torque of the steering motor, on the premise that the hardware cost is not increased, in the time period from tire burst to taking over of a driver, stable running of the vehicle is kept, and the driving stability and safety are improved.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles, in particular to an EPS-based automobile tire blowout safety protection method. Background Art

[0002] With the continuous growth of the number of cars, dealing with emergencies during driving and protecting the driver's safety have gradually become research hotspots. A tire blowout during high-speed driving is one of the important factors leading to traffic accidents, which may cause serious accidents that cause vehicle destruction and death. Therefore, when a tire blowout occurs, it is of great significance to better protect the vehicle and the driver.

[0003] After a car has a flat tire, the driving force on both sides of the tire changes, the contact friction between the wheel hub and the tire of the flat wheel decreases, and the vehicle tilts after the flat tire, making it prone to skidding or deviating from the lane, thereby causing a traffic accident.

[0004] At present, the mainstream tire blowout warning control solution is the tire pressure monitoring warning system TPMS, which can monitor tire pressure and temperature, warn the driver and promptly feed back the signal to the vehicle control system for emergency braking. However, after a tire blowout, the rolling resistance coefficient of the tire increases, and emergency braking of the vehicle may cause the tire to separate from the wheel hub, and the body posture will change significantly, resulting in the risk of rollover.

[0005] There are two types of technical solutions that have been explored more: one type uses hardware facilities such as vehicle radar and cameras to detect the vehicle's driving trajectory and body posture after a tire blowout, monitor the safe distance from surrounding vehicles, and control the vehicle's longitudinal and lateral movement at the same time, locking the vehicle's direction or braking when necessary. This solution relies too much on hardware equipment such as cameras and lidar, which increases vehicle costs and cannot provide safety protection for drivers in the event of hardware failure. Another type of solution uses a tire blowout vehicle dynamics model and complex control algorithms to collect the vehicle's current operating signals, conduct vehicle posture and hazard assessments, and systematically control the braking and steering systems to take measures in advance to avoid vehicle collisions or rollovers. However, complex control algorithms occupy too much processor computing resources, making coordinated control difficult, and the suspension, steering, and body movements of vehicles after a tire blowout are highly nonlinear and uncertain. There are many unfavorable factors that affect vehicle movement, and a single model and algorithm cannot comprehensively consider all influencing factors and vehicle movement, resulting in deviations in the reasoning results and limitations.

[0006] Therefore, it is necessary to design a car tire blowout safety protection method based on EPS to keep the vehicle driving stably during the period from the tire blowout to the driver taking over without increasing the hardware cost. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a vehicle tire blowout safety protection method based on EPS, which can keep the vehicle running stably during the period from the tire blowout to the driver taking over without increasing the hardware cost.

[0008] In order to achieve the above object, the present invention is a vehicle tire blowout safety protection method based on EPS, comprising the following steps:

[0009] Step 1: The signal processing unit obtains the tire pressure signal of the tire pressure monitoring and warning system, the wheel speed signals of the four tires, the vehicle speed signal, the vehicle yaw rate signal, the vehicle lateral acceleration signal, the hand force signal of the torque sensor, and the steering wheel angle signal through the CAN bus, and after verifying the validity of the signal, calculates the tire pressure change, wheel speed change, yaw rate change, and lateral acceleration change: x(t+1) is the next moment value, x(t) is the current moment value, Δt is n sampling cycles, and the steering speed and steering acceleration are determined according to the steering wheel angle signal.

[0010] Step 2: The tire blowout condition determination unit estimates the lateral acceleration based on the data from the signal processing unit. ω1 is the angular velocity of the inner wheel of the vehicle, ω2 is the angular velocity of the outer wheel of the vehicle, Rr is the wheel radius, L is the width between the inner and outer wheels of the vehicle, α is the wheel deflection angle, Vspd is the vehicle speed, and f θ is the coefficient of steering wheel angle; f ε is the coefficient that varies with tire pressure.

[0011] Step 3: Integrate the estimated lateral acceleration to obtain the tire runout. The integral formula is: LateAcc(t+1) is the lateral acceleration estimated at the next moment, and LateAcc(t) is the lateral acceleration estimated at the current moment.

[0012] Step 4, if the determined vehicle posture meets the following compensation conditions, the tire blowout torque compensation is turned on. If any of the compensation conditions is not met, the tire blowout torque compensation is not turned on: Compensation condition 1, the tire blowout safety protection function has not been turned on in the current power-on cycle, compensation condition 2, the signal collected by the protection function is not lost, compensation condition 3, the driver's hand force is lower than the set threshold, and the threshold setting range is 0.8~1.5Nm, compensation condition 4, the vehicle speed is higher than the set threshold, and the threshold setting range is 80km / h~100km / h, compensation condition 5, the steering wheel angle is less than the set threshold, and the threshold setting range is 30de g~45deg, compensation condition 6, the tire pressure change of a single tire within a certain period of time is greater than the set threshold, and the threshold setting range is 5bar / s~20bar / s, compensation condition 7, the wheel speed difference of a single wheel is greater than the set threshold compared with the wheel speed difference of other wheels, and the threshold setting range is 50kph / s~150kph / s, compensation condition 8, the lateral acceleration of the vehicle is greater than the set threshold, and the threshold setting range is 0.2m / s2~0.5m / s2, compensation condition 9, the runout of the tire blowout is greater than the set threshold, and the threshold setting range is 0.3deg / s~1.5deg / s.

[0013] Step 5: After the tire blowout torque compensation is turned on, the torque calculation unit uses the steering wheel angle closed-loop PID control to calculate the basic compensation torque, obtains the vehicle speed torque gain and the yaw rate torque gain by looking up the table, and calculates the motor torque required for the tire blowout protection function = basic compensation torque × vehicle speed torque gain × yaw rate torque gain, and keeps the steering wheel in the neutral position.

[0014] Step 6: After the tire blowout compensation is turned on, the function release unit determines whether the function release condition is met. If so, the tire blowout protection function torque output is reduced or cut off. If not, the tire blowout torque compensation is continued.

[0015] The step 2 also includes verifying the estimated lateral acceleration: verifying the estimated lateral acceleration with the tire blowout wheel mark, verifying the estimated lateral acceleration safety, and verifying the tire blowout wheel mark safety; the verified lateral acceleration is then verified again with the lateral acceleration collected from the whole vehicle, and the lateral acceleration compensation is determined.

[0016] In the step 3, before calculating the tire blowout runout amount, it is necessary to determine the consistency between the tire blowout position and the vehicle runout direction, and estimate the vehicle runout degree.

[0017] The calculation formula of the steering wheel angle closed-loop PID control is: K p is the proportionality coefficient, T I is the integration time constant, T D is the differential time constant, and S is a complex variable.

[0018] The vehicle speed torque gain is obtained by looking up Table 1 according to the vehicle speed, where the x-axis of Table 1 is the vehicle speed and the y-axis is the torque gain coefficient; the yaw angular velocity torque gain is obtained by looking up Table 2 according to the yaw angular velocity, where the x-axis of Table 2 is the yaw angular velocity and the y-axis is the torque gain coefficient.

[0019] In step 6, the function release conditions include release condition 1 and release condition 2. Release condition 1 is that the steering wheel torque is greater than the calibration threshold, and the calibration threshold range is 0.1 to 0.5 Nm. Release condition 2 is that it is determined that the steering wheel torque is not a road impact feedback torque.

[0020] The system also includes step 7, after the tire blowout compensation is turned on, if it is detected that the vehicle speed is lower than the set value, the torque calculation unit reduces the output torque to 0 according to the preset gradient, and the tire blowout compensation function is no longer turned on in the current power-on cycle, otherwise, the tire blowout torque compensation is continued, and the set value range is 0kph / s to 50kph / s ， The preset gradient is obtained by looking up Table 3 according to the vehicle speed, where the x-axis of Table 3 is the vehicle speed and the y-axis is the torque gradient.

[0021] The method also includes step 8, in which after the tire blowout compensation is turned on, the torque calculation unit calculates the compensation torque gradient of the two cycles before and after. If it is detected that the gradient exceeds the preset range, and the preset range is 0.1Nm / ms to 0.5Nm / ms, the torque exceeding the range is integrated and calculated. The integral formula is: CompTr(q(t+1) is the compensation torque at the next moment, CompTrq(t) is the compensation torque at the current moment, TargetTrqGrad(t) is the preset gradient threshold. If the integral value is greater than the preset threshold, and the preset threshold is 0.1Nm / ms~0.5Nm / ms, the compensation torque output is turned off, and the compensation torque output is restored when the gradient returns to the preset range and the integral is restored to below the preset threshold; if it is detected that the gradient is within the preset range, or the integral value is less than or equal to the preset threshold, the tire blowout torque compensation continues.

[0022] Under normal operating conditions, the system directly enters a Class A fault state, a Class B fault state or a Class C fault state according to the signal failure level, limits the compensation torque or directly shuts off the output, and prohibits the tire blowout protection function from being activated. Under a Class A fault state, if the failure signal returns to normal and then returns to normal operating conditions, the compensation torque will not be limited. If the number of failure signals increases or an important signal fails and is determined as a Class B fault, the system enters a Class B fault state. Under a Class B fault state, if the number of failure signals decreases and is determined as a Class A fault, the system enters a Class A fault state and reduces the maximum limit compensation torque. If the failure signal causes the torque calculation result to be unreliable and is determined as a Class C fault, the system enters a Class C fault state and prohibits the function from being activated.

[0023] The normal operating condition is that there is no signal loss or failure, and the compensation torque is output normally; the Class A fault is the failure of the speed signal of 1-2 wheel speeds or vehicle speeds or the failure of 1 tire pressure. The maximum compensation torque allowed to be output by the Class A fault is 80% of the maximum torque; the Class B fault is the failure of the speed signal of 3-4 wheel speeds or vehicle speeds or the failure of 2 tire pressures. The maximum compensation torque allowed to be output by the Class B fault is 60% of the maximum torque; the Class C fault is the failure of the speed signal of all wheel speeds or vehicle speeds or the failure of 3-4 tire pressures or the failure of the driver's hand force signal or the failure of the steering wheel angle signal or the failure of the vehicle body posture related signal. The Class C fault shuts off the torque output.

[0024] Compared with the prior art, the present invention controls the output torque of the steering motor, thereby maintaining stable driving of the vehicle during the period from a tire blowout to the driver taking over without increasing hardware costs, thereby improving driving stability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the present invention.

[0026] Figure 2 Flowchart for estimating lateral acceleration for the present invention.

[0027] Figure 3 The present invention is a flow chart for estimating the runout amount of a tire blowout.

[0028] Figure 4 This is a flow chart of the tire blowout torque compensation start determination according to the present invention.

[0029] Figure 5 The present invention is a flowchart of the tire blowout torque compensation release determination.

[0030] Figure 6 The present invention is a flow chart of the vehicle speed detection to release the tire blowout torque compensation.

[0031] Figure 7 Flow chart of the gradient and over-limit processing of the present invention.

[0032] Figure 8 This is a flow chart of power-on cycle determination of the present invention.

[0033] Fig. 9 This is a flow chart of the signal fault type state jump of the present invention. DETAILED DESCRIPTION

[0034] The present invention will now be further described with reference to the accompanying drawings.

[0035] See also Figure 1 The present invention is a vehicle tire blowout safety protection method based on EPS, comprising the following steps:

[0036] Step 1: The signal processing unit obtains the tire pressure signal of the tire pressure monitoring and warning system, the wheel speed signals of the four tires, the vehicle speed signal, the vehicle yaw rate signal, the vehicle lateral acceleration signal, the hand force signal of the torque sensor, and the steering wheel angle signal through the CAN bus, and after verifying the validity of the signal, calculates the tire pressure change, wheel speed change, yaw rate change, and lateral acceleration change: x(t+1) is the next moment value, x(t) is the current moment value, Δt is n sampling cycles, and the steering speed and steering acceleration are determined according to the steering wheel angle signal.

[0037] The tire pressure signal data includes the left front tire pressure, the right front tire pressure, the left rear tire pressure, and the right rear tire pressure. The wheel speed signals of the four tires include the left front wheel speed, the right front wheel speed, the left rear wheel speed, and the right rear wheel speed.

[0038] Step 2: The tire blowout condition determination unit estimates the lateral acceleration based on the data from the signal processing unit. ω1 is the angular velocity of the inner wheel of the vehicle, ω2 is the angular velocity of the outer wheel of the vehicle, Rr is the wheel radius, L is the width between the inner and outer wheels of the vehicle, α is the wheel deflection angle, Vspd is the vehicle speed, and f θ is the coefficient of steering wheel angle; f ε is the coefficient that changes with tire pressure, such as Figure 2 shown.

[0039] In order to improve the accuracy of the estimation, the estimated lateral acceleration is also verified: the estimated lateral acceleration is verified with the tire blown wheel mark, the estimated lateral acceleration safety is verified, and the tire blown wheel mark safety is verified; the verified lateral acceleration is then verified again with the lateral acceleration collected from the whole vehicle, and the lateral acceleration compensation is determined.

[0040] Step 3: Integrate the estimated lateral acceleration to obtain the tire runout. The integral formula is: LateAcc(t+1) is the lateral acceleration estimated at the next moment, and LateAcc(t) is the lateral acceleration estimated at the current moment.

[0041] like Figure 3 As shown, in order to improve the accuracy, before calculating the tire blowout runout, it is necessary to determine the consistency between the tire blowout position and the vehicle runout direction, and estimate the vehicle runout degree.

[0042] Step 4: If the determined vehicle posture meets the following compensation conditions, the tire blowout torque compensation is turned on. If any of the compensation conditions is not met, the tire blowout torque compensation is not turned on: Compensation condition 1: The tire blowout safety protection function has not been turned on in the current power-on cycle; Compensation condition 2: The signal collected by the protection function is not lost; Compensation condition 3: The driver's hand force is lower than the set threshold, and the threshold setting range is 0.8~1.5Nm; Compensation condition 4: The vehicle speed is higher than the set threshold, and the threshold setting range is 80km / h~100km / h; Compensation condition 5: The steering wheel angle is less than the set threshold, and the threshold setting range is 30deg ~45deg, compensation condition 6, the tire pressure change of a single tire within a certain period of time is greater than the set threshold, and the threshold setting range is 5bar / s~20bar / s, compensation condition 7, the wheel speed difference of a single wheel is greater than the set threshold compared with the wheel speed difference of other wheels, and the threshold setting range is 50kph / s~150kph / s, compensation condition 8, the lateral acceleration of the vehicle is greater than the set threshold, and the threshold setting range is 0.2m / s2~0.5m / s2, compensation condition 9, the runout of the tire blowout is greater than the set threshold, and the threshold setting range is 0.3deg / s~1.5deg / s, such as Figure 4 shown.

[0043] like Figure 8 As shown, the system first detects whether the tire blowout safety protection function has been turned on in the current power-on cycle. If not, the subsequent compensation conditions are determined, and torque compensation is turned on when all conditions are met, the vehicle state is controlled, and a record is made when the compensation is released; if so, the tire blowout safety protection function is no longer turned on in the current power-on cycle.

[0044] Step 5: After the tire blowout torque compensation is turned on, the torque calculation unit uses the steering wheel angle closed-loop PID control to calculate the basic compensation torque, obtains the vehicle speed torque gain and the yaw rate torque gain by looking up the table, and calculates the motor torque required for the tire blowout protection function = basic compensation torque × vehicle speed torque gain × yaw rate torque gain, and keeps the steering wheel in the neutral position.

[0045] The calculation formula for the closed-loop PID control of the steering wheel angle is: K p is the proportionality coefficient, T I is the integration time constant, T D is the differential time constant, and S is a complex variable.

[0046] The vehicle speed torque gain is obtained by looking up Table 1 according to the vehicle speed, the x-axis of Table 1 is the vehicle speed, and the y-axis is the torque gain coefficient; the yaw rate torque gain is obtained by looking up Table 2 according to the yaw rate, the x-axis of Table 2 is the yaw rate, and the y-axis is the torque gain coefficient. For example, the x-axis of Table 1 is the vehicle speed [80; 90; 100; 120; 150], and the y-axis is the torque gain coefficient [0.3; 0.5; 0.8; 1; 1.3]; the x-axis of Table 2 is the yaw rate [0.2; 0.25; 0.3; 0.45; 0.6], and the y-axis is the torque gain coefficient [0.8; 0.9; 1.2; 1.3; 1.5].

[0047] Step 6: After the tire blowout compensation is turned on, the function release unit determines whether the function release condition is met. If so, the tire blowout protection function torque output is reduced or cut off. If not, the tire blowout torque compensation is continued.

[0048] like Figure 5 As shown in the figure, the function release conditions include release condition 1 and release condition 2. Release condition 1 is that the steering wheel torque is greater than the calibration threshold, and the calibration threshold range is 0.1-0.5Nm. Release condition 2 is that the steering wheel torque is not the road impact feedback torque. When release condition 1 and release condition 2 are met at the same time, it can be judged that the driver intervenes, and the torque output of the tire blowout protection function is reduced or cut off to release the protection control; otherwise, it is considered that the driver has not intervened, and the tire blowout torque compensation is allowed to continue.

[0049] Step 7: After the tire blowout compensation is turned on, if it is detected that the vehicle speed is lower than the set value, the torque calculation unit will reduce the output torque to 0 according to the preset gradient, and will not turn on the tire blowout compensation function in the current power-on cycle. Otherwise, the tire blowout torque compensation will continue, and the set value range is 0kph / s to 50kph / s. Figure 6 shown.

[0050] The preset gradient is obtained by looking up Table 3 according to the vehicle speed, where the x-axis of Table 3 is the vehicle speed and the y-axis is the torque gradient. For example, the x-axis of Table 3 is the vehicle speed [50; 60; 70; 75; 80] and the y-axis is the torque gradient [0.05; 0.07; 0.1; 0.15; 0.3].

[0051] Step 8: After the tire blowout compensation is turned on, the torque calculation unit calculates the compensation torque gradient of the two cycles before and after. If it is detected that the gradient exceeds the preset range, and the preset range is 0.1Nm / ms to 0.5Nm / ms, the torque exceeding the range is integrated and calculated. The integral formula is: CompTrq(t+1) is the compensation torque at the next moment, CompTrq(t) is the compensation torque at the current moment, TargetTrqGrad(t) is the preset gradient threshold. If the integral value is greater than the preset threshold, and the preset threshold is 0.1Nm / ms~0.5Nm / ms, the compensation torque output is turned off, and the compensation torque output is restored when the gradient returns to the preset range and the integral is restored to below the preset threshold; if it is detected that the gradient is within the preset range, or the integral value is less than or equal to the preset threshold, the tire blowout torque compensation continues, such as Figure 7 shown.

[0052] like Fig. 9 As shown, under normal working conditions, the system directly enters the A-type fault state, the B-type fault state or the C-type fault state according to the signal failure level, limits the compensation torque or directly shuts off the output, and prohibits the tire blowout protection function from being turned on; in the A-type fault state, if the failure signal returns to normal after returning to normal working conditions, the compensation torque is not limited. If the number of failure signals increases or an important signal fails and is determined as a B-type fault, the system enters the B-type fault state; in the B-type fault state, if the number of failure signals decreases and is determined as an A-type fault, the system enters the A-type fault state and reduces the maximum limit compensation torque. If the failure signal causes the torque calculation result to be unreliable and is determined as a C-type fault, the system enters the C-type fault state and prohibits the function from being turned on.

[0053] When different types of signals fail at the same time, the most serious type of failure is selected for functional failure determination.

[0054] The normal working condition is that there is no signal loss or failure, and the compensation torque is output normally.

[0055] Class A faults are failures of 1-2 wheel speed or vehicle speed signals or failure of 1 tire pressure. Class A faults are mild faults with a small number of failure signals and do not affect the torque calculation in the protection function. The maximum compensation torque allowed to be output by a Class A fault is 80% of the maximum torque.

[0056] Class B faults are failures of 3-4 wheel speed or vehicle speed signals or failure of 2 tire pressures. Class B faults are moderate faults with a large number of failure signals, which results in a decrease in the credibility of the calculated compensation torque and the inability to exert the optimal performance of the tire blowout protection function. The maximum compensation torque allowed to be output for Class B faults is 60% of the maximum torque.

[0057] Class C faults are failure of speed signals of all wheel speeds or vehicle speed, failure of 3-4 tire pressure, failure of driver's hand force signal, failure of steering wheel angle signal, or failure of vehicle body posture related signals. Class C faults are serious faults. Failure signals may cause large deviations in torque calculation results, or cause the compensation torque to be unable to be calculated. The calculation results are considered unreliable, and Class C faults shut down the torque output.

Claims

1. A vehicle tire blowout safety protection method based on EPS, characterized by: The steps include: Step 1: The signal processing unit obtains the tire pressure signal of the tire pressure monitoring and warning system, the wheel speed signals of the four tires, the vehicle speed signal, the vehicle yaw rate signal, the vehicle lateral acceleration signal, the hand force signal of the torque sensor, and the steering wheel angle signal through the CAN bus, and after verifying the validity of the signal, calculates the tire pressure change, wheel speed change, yaw rate change, and lateral acceleration change: x(t+1) is the next moment value, x(t) is the current moment value, Δt is n sampling cycles, and the steering speed and steering acceleration are determined according to the steering wheel angle signal; Step 2: The tire blowout condition determination unit estimates the lateral acceleration based on the data from the signal processing unit. ω1 is the angular velocity of the inner wheel of the vehicle, ω2 is the angular velocity of the outer wheel of the vehicle, Rr is the wheel radius, L is the width between the inner and outer wheels of the vehicle, α is the wheel deflection angle, Vspd is the vehicle speed, and f θ is the coefficient of steering wheel angle; f ε is the coefficient that changes with tire pressure; Step 3: Integrate the estimated lateral acceleration to obtain the tire runout. The integral formula is: LateAcc(t+1) is the estimated lateral acceleration at the next moment, and LateAcc(t) is the estimated lateral acceleration at the current moment; Step 4, if the determined vehicle posture meets the following compensation conditions, the tire blowout torque compensation is turned on. If any of the compensation conditions is not met, the tire blowout torque compensation is not turned on: Compensation condition 1, the tire blowout safety protection function has not been turned on in the current power-on cycle, compensation condition 2, the signal collected by the protection function is not lost, compensation condition 3, the driver's hand force is lower than the set threshold, and the threshold setting range is 0.8~1.5Nm, compensation condition 4, the vehicle speed is higher than the set threshold, and the threshold setting range is 80km / h~100km / h, compensation condition 5, the steering wheel angle is less than the set threshold, and the threshold setting range is 30de g~45deg, compensation condition 6, the tire pressure change of a single tire within a certain period of time is greater than the set threshold, and the threshold setting range is 5bar / s~20bar / s, compensation condition 7, the wheel speed difference of a single wheel is greater than the set threshold compared with the wheel speed difference of other wheels, and the threshold setting range is 50kph / s~150kph / s, compensation condition 8, the lateral acceleration of the vehicle is greater than the set threshold, and the threshold setting range is 0.2m / s2~0.5m / s2, compensation condition 9, the runout of the tire blowout is greater than the set threshold, and the threshold setting range is 0.3deg / s~1.5deg / s; Step 5: After the tire blowout torque compensation is turned on, the torque calculation unit uses the steering wheel angle closed-loop PID control to calculate the basic compensation torque, obtains the vehicle speed torque gain and the yaw rate torque gain by looking up the table, and calculates the motor torque required for the tire blowout protection function = basic compensation torque × vehicle speed torque gain × yaw rate torque gain, and keeps the steering wheel in the neutral position; Step 6: After the tire blowout compensation is turned on, the function release unit determines whether the function release condition is met. If so, the tire blowout protection function torque output is reduced or cut off. If not, the tire blowout torque compensation is continued.

2. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: The step 2 also includes verifying the estimated lateral acceleration: verifying the estimated lateral acceleration with the tire blowout wheel mark, verifying the estimated lateral acceleration safety, and verifying the tire blowout wheel mark safety; the verified lateral acceleration is then verified again with the lateral acceleration collected from the whole vehicle, and the lateral acceleration compensation is determined.

3. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: In the step 3, before calculating the tire blowout runout amount, it is necessary to determine the consistency between the tire blowout position and the vehicle runout direction, and estimate the vehicle runout degree.

4. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: The calculation formula of the steering wheel angle closed-loop PID control is: K p is the proportionality coefficient, T I is the integration time constant, T D is the differential time constant, and S is a complex variable.

5. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: The vehicle speed torque gain is obtained by looking up Table 1 according to the vehicle speed, where the x-axis of Table 1 is the vehicle speed and the y-axis is the torque gain coefficient; the yaw angular velocity torque gain is obtained by looking up Table 2 according to the yaw angular velocity, where the x-axis of Table 2 is the yaw angular velocity and the y-axis is the torque gain coefficient.

6. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: In step 6, the function release conditions include release condition 1 and release condition 2. Release condition 1 is that the steering wheel torque is greater than the calibration threshold, and the calibration threshold range is 0.1 to 0.5 Nm. Release condition 2 is that it is determined that the steering wheel torque is not a road impact feedback torque.

7. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: The method also includes step 7. After the tire blowout compensation is turned on, if it is detected that the vehicle speed is lower than the set value, the torque calculation unit reduces the output torque to 0 according to the preset gradient, and the tire blowout compensation function is no longer turned on in the current power-on cycle. Otherwise, the tire blowout torque compensation continues, and the set value range is 0kph / s to 50kph / s. The preset gradient is obtained by looking up Table 3 according to the vehicle speed. The x-axis of Table 3 is the vehicle speed, and the y-axis is the torque gradient.

8. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: The method also includes step 8, in which after the tire blowout compensation is turned on, the torque calculation unit calculates the compensation torque gradient of the two cycles before and after. If it is detected that the gradient exceeds the preset range, and the preset range is 0.1Nm / ms to 0.5Nm / ms, the torque exceeding the range is integrated and calculated. The integral formula is: CompTrq(t+1) is the compensation torque at the next moment, CompTrq(t) is the compensation torque at the current moment, TargetTrqGrad(t) is the preset gradient threshold. If the integral value is greater than the preset threshold, and the preset threshold is 0.1Nm / ms~0.5Nm / ms, the compensation torque output is shut down, and the compensation torque output is restored when the gradient returns to the preset range and the integral is restored to below the preset threshold; if it is detected that the gradient is within the preset range, or the integral value is less than or equal to the preset threshold, the tire blowout torque compensation continues.

9. The EPS-based automobile tire blowout safety protection method according to claim 1, characterized in that: Under normal working conditions, the system will directly enter the A-type fault state, B-type fault state or C-type fault state according to the signal failure level, and limit the compensation torque or directly shut down the output, and prohibit the tire blowout protection function from being turned on; under the A-type fault state, if the failure signal returns to normal and returns to normal working conditions, the compensation torque will not be limited. If the number of failure signals increases or an important signal failure is determined as a B-type fault, the system will enter the B-type fault state; In the Class B fault state, if the number of failure signals decreases and it is determined to be a Class A fault, it enters the Class A fault state and reduces the maximum limit compensation torque. If the failure signal causes the torque calculation result to be unreliable and it is determined to be a Class C fault, it enters the Class C fault state and the prohibition function is turned on.

10. The EPS-based automobile tire blowout safety protection method according to claim 9, characterized in that: The normal operating condition is that there is no signal loss or failure, and the compensation torque is output normally; the Class A fault is the failure of the speed signal of 1-2 wheel speeds or vehicle speeds or the failure of 1 tire pressure. The maximum compensation torque allowed to be output by the Class A fault is 80% of the maximum torque; the Class B fault is the failure of the speed signal of 3-4 wheel speeds or vehicle speeds or the failure of 2 tire pressures. The maximum compensation torque allowed to be output by the Class B fault is 60% of the maximum torque; the Class C fault is the failure of the speed signal of all wheel speeds or vehicle speeds or the failure of 3-4 tire pressures or the failure of the driver's hand force signal or the failure of the steering wheel angle signal or the failure of the vehicle body posture related signal. The Class C fault shuts off the torque output.

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