A device for warning of turning and lane changing of a battery car

Abstract

The application discloses a device for turning and lane-changing warning of an electric vehicle, which comprises a turn signal, a distance measuring sensor, a gyroscope and a damper, and the turning damping device is adjusted to the turning behavior through target detection and dangerous coefficient discrimination algorithm of the rear side of the electric vehicle, so that the safety of the electric vehicle driver when turning is improved without the driver's awareness of the rear vehicle. When the driver turns or changes lanes, the risk of the rear vehicle is judged, and the size of the turning damping is adjusted according to the dangerous coefficient, so that the effect of reminding the electric vehicle driver of the rear danger is achieved, and the safety of the electric vehicle driver is ensured. At the same time, the turn signal is turned on to remind the rear vehicle that the electric vehicle will turn.

Description

Technical Field

[0001] This invention relates to a safety device for driving small electric vehicles, and more particularly to a device for warning electric vehicles when turning or changing lanes. Background Technology

[0002] According to data released by the China Bicycle Association, by the end of 2022, the number of electric bicycles in my country had reached approximately 350 million. The accident rate of electric bicycles is relatively high. Depending on different data sources and regions, the accident rate of electric bicycles may be 3-5 times higher than that of other vehicles in some cases, and the fatal risk per kilometer is approximately 15-20 times that of cars. Some studies indicate that the high accident rate of electric bicycles is partly due to users' lack of awareness of traffic risks, as well as safety hazards in some high-risk road sections. In some cities, approximately 40% to 50% of electric bicycle accidents are caused by the riders themselves, with high-risk road sections being intersections, pedestrian crossings, and motor vehicle lanes. Furthermore, behaviors such as making phone calls or looking at mobile phones while riding electric bicycles also increase the probability of accidents. Therefore, to reduce the accident rate of electric bicycles, it is necessary to strengthen traffic safety education and publicity, improve users' awareness of traffic risks, and improve the road traffic environment to enhance the safety of electric bicycles.

[0003] During daily driving, electric bicycle riders often make unprepared lane changes or turns without using turn signals or checking for vehicles behind them, posing a significant safety hazard. Vehicles behind them are often caught off guard by these sudden lane changes or turns without turn signals, leading to traffic accidents. Summary of the Invention

[0004] Purpose of the invention: To address the above problems, this invention proposes a device for warning electric bicycles when turning or changing lanes. When the electric bicycle driver makes a dangerous turn or lane change, the device can forcibly activate the turn signal to warn vehicles behind. At the same time, it can judge the degree of danger of the vehicles behind and adjust the magnetic damper according to the degree of danger to warn the electric bicycle driver of the danger of turning or changing lanes. It can also prevent dangerous turning or lane change behavior to a certain extent.

[0005] Technical Solution: The technical solution adopted in this invention is a device for warning electric bicycles when turning and changing lanes, including a processor, a distance sensor, a damper, and a gyroscope. The distance sensor measures the relative distance between the electric bicycle and vehicles behind it; the gyroscope detects the electric bicycle driver's turning and lane-changing behavior by measuring angular velocity. The processor adjusts the damping magnitude of the damper using a hazard factor discrimination algorithm to suppress or prevent unsafe turning behavior by the electric bicycle driver, thus ensuring the driver's safety. The hazard factor discrimination algorithm, based on data obtained from the distance measurement by the sensor and the electric bicycle's speed, regulates the input current of the magnetic damper to achieve the effect of adjusting the turning damping to ensure the safety of the electric bicycle driver.

[0006] Preferably, when the driver of the electric vehicle makes a dangerous turn or changes lanes, the driver is forced to automatically turn on the turn signal to alert vehicles behind.

[0007] Preferably, the device also includes a photosensitive element for assessing hazard levels at different coefficients during the day and night. The ranging sensor is an ultrasonic ranging sensor, and the damper is a magnetic damper. The magnitude of the magnetic field in the magnetic damper is controlled and adjusted according to the input current, thereby changing the magnetic force on the metal conductor connected to the front wheel axle of the electric vehicle within the magnetic damper, thus generating turning damping.

[0008] Specifically, the magnetic damper includes an internal and an external portion. The internal portion is a rotor structure made of insulating material and contains several metal conductors. The external portion is an energized helical coil used to provide a magnetic field. The rotor is mounted on the steering axle of the front wheel of the electric vehicle. When the axle rotates, it drives the metal conductors on the rotor structure to rotate.

[0009] The hazard factor discrimination algorithm includes: raw data processing, preprocessing the distance data measured by the ranging sensor to obtain reliable data; calculating the hazard factor when the electric vehicle is turning or changing lanes; calculating the required damping based on the hazard factor; and calculating the regulating current based on the required damping magnitude.

[0010] Specifically, the relative distance S is obtained by an ultrasonic sensor. n The time difference t between two ultrasonic ranging measurements c The speed of this vehicle is v1, from which the speed of the following vehicle v2 can be calculated.

[0011] v x =(S n -S n-1 ) / t c

[0012] v2 = v1 + v x

[0013] vx This represents the relative speed between this vehicle and the vehicle behind it.

[0014] The electric scooter's trajectory can be obtained using a gyroscope to determine the angular velocity ω during lane changes (turns), and the scooter's speedometer can provide the speed v1. The turning radius R can then be calculated using a formula.

[0015]

[0016] Establish a coordinate system with the electric scooter as the origin. The lateral distance of the electric scooter when changing lanes (turning) is X = 1.5m, and the longitudinal distance is Y. X and Y can be calculated using the formula:

[0017] X = R·sin(ω·t)

[0018]

[0019] Y = R·[1-cos(ω·t)]

[0020] This invention, on the one hand, uses an ultrasonic ranging sensor to monitor the distance between the vehicle and the following vehicle in real time; on the other hand, it uses a safe braking distance model to classify the collision risk of the following vehicle. Generally speaking, vehicle speed, braking performance, and the reaction time of the driver and the system affect the safe braking distance of a vehicle. This paper divides the braking process of the following vehicle into three stages: driver reaction time, vehicle response time, and vehicle braking time. In the first stage, the driver reaction stage, the average driver reaction time is taken as t1 = 0.5s, and the distance traveled by the following vehicle in this stage is D1.

[0021] D1 = v2·t1

[0022] In the second stage, the vehicle response stage, the vehicle response time is taken as t2 = 0.2s, and the distance the car travels in this stage is D2.

[0023] D2=v2·t2

[0024] The third stage is the vehicle braking stage. The distance traveled during this stage is related to the braking deceleration selected by the driver. When the vehicle decelerates at a comfortable rate (a1 = -1.5 m / s²), the braking distance is... 2 When decelerating, the car travels a distance of D3.

[0025]

[0026] t represents the time it takes for the electric vehicle to turn and change lanes.

[0027] The car decelerates at a comfortable speed (a1 = -1.5 m / s²). 2 The distance D traveled during the braking process.

[0028]

[0029] To provide appropriate turning damping for drivers during risky turns, electrical signals are used for transmission. A value C, greater than 0 and less than 1, represents the risk factor, and the current is adjusted to an appropriate value based on C.

[0030]

[0031] Set ω1=0.4, ω2=0.5, ω3=0.1, v m = max{v1, v2}, where ω1, ω2, ω3 can be adjusted according to the actual situation.

[0032] The model considers the impact of the preceding vehicle's travel distance, the following vehicle's braking distance, relative distance, and speed differences on collision risk. Weighting coefficients can be adjusted based on actual conditions to reflect the relative importance of each factor. The speed difference term is normalized using maximum speed to ensure its influence in the model is within a reasonable range.

[0033] When C≥1, the electric vehicle is in the most dangerous state, and the damping of the magnetic damper should be adjusted to the maximum.

[0034] At this point, the relationship between the danger factor of the electric vehicle and the magnitude of the damping force has been determined. Further calculations are needed to design the damping force of the magnetic damper, so that the current flowing through the electric vehicle's circuit can regulate the magnitude of the magnetic damper's damping force. The design principle of the magnetic damper of this invention and the derivation of the relationship between the damping force and the current in the electric vehicle's circuit are as follows:

[0035] The design concept of a magnetic damper is to use a magnetic field to apply damping force to the rotor (the rotating shaft of an electric vehicle), utilizing the principle of eddy current braking. Eddy current braking is a method of generating damping force by inducing eddy currents, and is commonly used to brake rotating objects.

[0036] The following are the control steps and principles of a magnetic damper:

[0037] 1. Introducing a magnetic field: Introducing a magnetic field near a metallic conductor. This can be achieved by placing a permanent magnet around the metallic conductor or by using a coil that generates a magnetic field when energized.

[0038] 2. Metal conductor motion: Ensure the metal conductor moves in a circular motion within this magnetic field. In this invention, the rotor is connected to the axle of the front wheel of the electric vehicle.

[0039] 3. Induced Eddy Currents: When a metallic conductor moves in a magnetic field, eddy currents are induced in the conductor. Eddy currents are induced currents caused by changes in the magnetic field, and their direction is opposite to the direction of the magnetic field change.

[0040] 4. Eddy current damping: Due to the presence of eddy currents, the metal conductor will be subjected to eddy current braking force, which will produce a damping effect. The magnitude of the braking force depends on the intensity of the eddy currents, which is related to the speed of the metal conductor and the strength of the magnetic field.

[0041] In this invention, a energized coil is used to generate a magnetic field to achieve the required controllable magnetic field strength. The formula for calculating the eddy current braking force is as follows:

[0042] F = -B 2 ·A·d·v.σ

[0043] F is the magnitude of the eddy current braking force, B is the magnetic induction intensity, which is adjusted by the energized helical coil, A is the cross-sectional area of ​​the conductor, d is the thickness of the conductor, v is the speed of the conductor, which is replaced by the rotor angular velocity ω in this invention, and σ is the conductivity of the conductor.

[0044] For a current-carrying spiral coil in a circular loop, its internal magnetic field can be calculated using Ampere's law of current circulation. The magnetic field along the central axis of the loop is uniform, and the magnetic flux density at any point outside the axis can be calculated using the following formula:

[0045]

[0046] Where: B is the magnetic flux density, μ is the permeability, N is the number of turns of the coil, I is the current flowing through the coil, R is the radius of the circular current-carrying helical coil, and z is the perpendicular distance from the measuring point to the central axis of the ring. Because the magnetic flux density outside the axis is not uniform, the specific magnetic field strength experienced by the rotor's metal conductor can be approximated by integration:

[0047]

[0048] This value is the average magnetic field strength at the location of the conductor, which can be substituted into the formula for eddy current braking force.

[0049]

[0050] Therefore:

[0051]

[0052] The rotor of the magnetic damper has n metal conductors, so the eddy current braking force should be n times F.

[0053] The relationship between the risk factor C and F is as follows:

[0054]

[0055] It is an adjustable parameter that controls the sensitivity of resistance and risk coefficient. 10 is a constant, which means that when the electric vehicle begins to turn (change lanes) without turning on the turn signal, the magnetic damper will provide a damping force to remind the electric vehicle driver to pay attention and turn on the turn signal, regardless of whether there are dangerous vehicles behind.

[0056] Beneficial Effects: Compared with existing technologies, this invention has the following advantages: This invention can assess the danger level of vehicles behind when an electric scooter driver makes a dangerous turn or lane change, and adjust the magnetic damper according to the danger level to provide a warning of the driver's turning or lane change behavior, while also preventing dangerous turning or lane change behavior to a certain extent. When the electric scooter begins to turn (change lanes) without using its turn signal, regardless of whether there are dangerous vehicles behind, the magnetic damper will provide a damping force to remind the driver to be cautious and activate the turn signal. This invention, by providing adjustable turning damping, promptly reminds electric scooter drivers when they unintentionally (regardless of vehicles behind) make turning or lane change behaviors, and provides different levels of prevention based on different risk levels, to ensure the personal safety of the electric scooter driver and remind the driver to correct their behavior. Attached Figure Description

[0057] Figure 1 This is a structural diagram of the magnetic damper in this embodiment;

[0058] Figure 2 This is a flowchart illustrating the risk factor discrimination algorithm described in this invention;

[0059] Figure 3 It is a curve showing the relationship between resistance and risk coefficient. Detailed Implementation

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0061] Example 1

[0062] The device for warning electric bicycles when turning and changing lanes, as described in this invention, includes a distance sensor, a magnetic damper, a gyroscope, and a hazard factor discrimination algorithm for adjusting the damping magnitude of the magnetic damper. The ultrasonic distance sensor measures the relative distance between the electric bicycle and vehicles behind it; this sensor can be replaced depending on cost and other factors. The gyroscope detects the driver's turning and lane-changing behavior by measuring changes in angular velocity. The magnetic damper adjusts its magnetic field strength based on the current input. Turning damping is generated by the force exerted on the magnetic field by a metal conductor connected to the front wheel axle of the electric bicycle, thereby suppressing or preventing unsafe turning maneuvers by the driver and ensuring their safety. The hazard factor discrimination algorithm adjusts the input current of the magnetic damper based on data from the distance sensor and the electric bicycle's speed, achieving the effect of adjusting the turning damping to ensure the driver's safety. When the driver makes a dangerous turn or lane change, the turn signal is automatically activated to warn vehicles behind.

[0063] Figure 1 This is a schematic diagram of a magnetic damper structure. The structure includes a fixing screw 1, an inner wall of the magnetic damper 2, a magnetic damper coil 3 (providing a controllable magnetic field), an internal metal conductor 4 (the main structure of the rotor assembly), and a magnetic damper housing 5. An opening 6 is used to fix the coil to the inner wall, and a magnetic damper circuit interface 7 is used to input current. In this embodiment, the rotor of the magnetic damper has eight metal conductors, so the eddy current braking force should be eight times F. Based on the average human arm strength, the maximum damping force F is designed. m The current is 300N. When the magnetic damper coil is energized, it provides a magnetic field to the rotor inside the damper. The rotor is mounted on the front turning post of the electric scooter and has the same angular velocity as the scooter's turning and lane-changing behavior. Rotating in the magnetic field, the rotor receives eddy current braking force, which in turn provides the driver with a turning damping force. Figure 3 The diagram shows the relationship between resistance and risk coefficient. The process ends. The driver receives turning damping, which somewhat inhibits turning and lane-changing behavior. The electric scooter driver recognizes the risk and stops turning and changing lanes, ensuring their safety. The turn signal is forcibly activated, warning following vehicles of the electric scooter's turning and lane-changing behavior, allowing them to take evasive action and avoid an accident.

[0064] The electric scooter obtains the real-time relative distance between itself and other vehicles by measuring the distance to vehicles behind it using an ultrasonic ranging sensor. When the gyroscope installed on the front of the scooter detects the driver's turning or lane-changing behavior through changes in angular velocity, the algorithm enters the process. Based on different results, a preliminary judgment is made on the distance and relative speed to determine whether the following vehicle is a risk vehicle (excluding parked vehicles or vehicles being overtaken). If a risk vehicle is found, the algorithm proceeds to the next step to determine the risk factor. Based on the risk factor, the circuit current is adjusted to regulate the turning damping generated by the magnetic damper, thereby alerting the scooter driver and helping them avoid risks. At the same time, the turn signal is activated to warn vehicles behind.

[0065] For economic reasons, this invention uses an ultrasonic ranging sensor to measure the actual distance between the electric vehicle and the following vehicle. Due to the characteristics of ultrasonic sensors and their installation location, when the electric vehicle turns (changes lanes), the distance measured by the ultrasonic ranging sensor is no longer in the horizontal direction of the road, making it difficult to design algorithms and determine dangerous distances. Therefore, an algorithm is designed to use the data from the ultrasonic ranging sensor before the electric vehicle turns (changes lanes) to perform corresponding calculations, derive a danger coefficient, and use this coefficient to adjust the damping of the magnetic damper. The algorithm retrieves a set of distance data obtained from the ultrasonic sensor and selects the last two data points S before the electric vehicle turns or changes lanes. n S n-1 If the difference between two sets of data is less than the threshold set by the algorithm, the data can be used.

[0066] Difference = |S n-1 -S n |

[0067] A difference threshold is set, and when the difference exceeds this threshold, an alternative mechanism is triggered. The difference threshold is set to the distance the car travels at 100 km / h within the ranging time interval of the ultrasonic sensor. For example, when the ranging time interval of the ultrasonic sensor is 50 milliseconds, the difference threshold is set to 1.4. When the difference exceeds the threshold, an exponentially weighted moving average (EMA) method is used to obtain a more reliable estimate.

[0068] EMA n-1 =α·S n-1 +(1-α)·EMA n-2

[0069] EMA n =α·S n-1 +(1-α)·EMA n-1

[0070] Here, α is the smoothing coefficient, which can be adjusted according to actual needs.

[0071] Next, according to S n S n-1 Calculate the relative speed v from the speedometer reading v1 of the electric scooter itself. x And the speed of the following vehicle v2; calculate the lateral displacement distance X = R·sin(ω·t) when the electric vehicle turns and changes lanes, and get Longitudinal distance Y = R·[1-cos(ω·t)]; Calculate the distance required for the following vehicle to brake: Proceed to the next step in the algorithm flow: Calculate the risk factor. Moving to the next step of the algorithm flow, the required damping force is calculated based on the risk factor: The constant 10 in the formula indicates that when the electric scooter begins to turn (change lanes) without using its turn signal, the magnetic damper will provide a damping force of 10 units to remind the scooter driver to activate the turn signal, regardless of whether there are dangerous vehicles behind. The final step is based on the relationship between damping force and current: Substitute the values ​​into the equation to obtain the current magnitude, and then adjust the damping magnitude accordingly.

[0072] Example 2

[0073] The device for warning electric vehicles when turning or changing lanes is basically the same as in Embodiment 1, and also includes a photosensitive element. For example... Figure 2 The diagram shows a flowchart of the hazard factor judgment algorithm in a turn and lane change warning device for electric bicycles containing a photosensitive element. During the electric bicycle's operation, the driver's turn and lane change actions are detected by a gyroscope installed on the front of the bicycle. When the gyroscope detects angular velocity, the algorithm begins. An ultrasonic ranging sensor installed on the rear of the bicycle detects the real-time distance to the vehicle behind, and based on the distance measurement time interval, calculates the relative speed between the two vehicles, proceeding to the next step. If the photosensitive element determines it is nighttime, the algorithm proceeds to the next step. If the relative distance between the two vehicles is less than 50m, a positive or negative judgment is made regarding the relative speed v. x If the value is positive, the speed of the electric vehicle is less than the speed of the vehicle behind it. The risk factor is calculated, and the vehicle behind it is determined to be a high-risk vehicle. The magnetic damper provides a maximum damping force of 300N.

[0074] Figure 1 When the magnetic damper coil is energized, it provides a magnetic field to the rotor inside the magnetic damper. The rotor is mounted on the front turning post of the electric vehicle and has the same angular velocity as the electric vehicle's turning and lane-changing behavior. It rotates in the magnetic field and obtains eddy current braking force, that is, the driver obtains the maximum turning damping force to prevent turning and lane-changing behavior. At the same time, the turn signal is turned on to warn the following vehicles and remind them to avoid the vehicle in advance.

[0075] Example 3

[0076] During the electric scooter's operation, the driver's turning and lane-changing actions are detected by a gyroscope mounted on the front of the scooter. When the gyroscope detects angular velocity, the device enters the algorithm flow. Using an ultrasonic ranging sensor mounted on the rear of the scooter, it detects the real-time distance to the vehicle behind and calculates the relative speed between the two vehicles based on the distance measurement time interval, proceeding to the next step. If the system determines it is daytime based on a photosensor, it proceeds to the next step. If the relative distance between the two vehicles is determined to be no less than 50m, the relative speed is assessed for positive or negative values. The relative speed v... x If the value is negative, the electric scooter's speed is greater than the speed of the vehicle behind it. The vehicle behind it is determined to be a risk-free vehicle, the algorithm process ends, and the magnetic damper provides a minimum damping force of 10N to remind the electric scooter driver to take precautions and turn on the turn signal.

Claims

1. A device for warning electric vehicles when turning or changing lanes, characterized in that: It includes a processor, a controller, a distance sensor, a gyroscope, and a damper; the distance sensor is used to measure the relative distance between the electric vehicle and the vehicle behind it and to calculate the relative speed; the gyroscope is used to detect whether there is a turning or lane-changing behavior by measuring the angular velocity. The processor calculates the risk factor based on the distance sensor data, gyroscope data, and vehicle driving data using a risk factor discrimination algorithm, and the controller adjusts the damping magnitude of the damper according to the risk factor. The hazard factor discrimination algorithm includes: raw data processing, reliability judgment of distance data measured by the ranging sensor, and replacement of unreliable data with data estimated by the exponential weighted moving average method; hazard factor calculation when the electric vehicle is turning or changing lanes; calculation of the required damping based on the hazard factor; and calculation of the adjustment current based on the required damping magnitude. The formula for calculating the risk factor is: In the formula, C is the risk coefficient, Y is the longitudinal travel distance of the electric vehicle during the turning and lane-changing process, and D is the distance required for the following vehicle to brake. These represent the last valid distance data before the electric vehicle begins its turning and lane-changing maneuvers; ω1, ω2, and ω3 are adjustment coefficients. For the speed of the electric scooter itself, For the speed of the following vehicle, The maximum speed of the two vehicles. ; The formulas for calculating the longitudinal travel distance Y of an electric bicycle during a turn and lane change, and the distance D required for the following vehicle to brake, are as follows: In the formula, R is the turning radius of the electric vehicle, ω is the angular velocity measured by the gyroscope, t is the turning time of the electric vehicle, X is the lateral distance of the electric vehicle turning and changing lanes, t1 is the average reaction time of the driver, t2 is the vehicle response time, and a1 is the deceleration. The formula for calculating the required damping is: In the formula F 阻尼力 For the required damping, F m For the maximum damping force, These are adjustment parameters, C is the risk coefficient, and o is a constant.

2. The device for warning electric vehicles turning and changing lanes according to claim 1, characterized in that: When an electric vehicle is detected to be turning or changing lanes, the turn signal will be forcibly activated to alert vehicles behind.

3. The device for warning electric vehicles turning and changing lanes according to claim 1, characterized in that: The device also includes a photosensitive element for assessing danger at different rates during the day and at night.

4. The device for warning electric vehicles turning and changing lanes according to claim 1, characterized in that: The ranging sensor is an ultrasonic ranging sensor; the damper is a magnetic damper, and the metal conductor in the magnetic field of the magnetic damper is connected to the axle of the front wheel of the electric vehicle; the magnetic damper controls the magnitude of the magnetic field in the magnetic damper according to the magnitude of the input current, thereby changing the magnetic field force on the metal conductor connected to the axle of the front wheel of the electric vehicle in the magnetic damper, and generating turning damping.

5. The device for warning electric vehicles turning and changing lanes according to claim 4, characterized in that: The magnetic damper includes an internal and an external component. The internal component is a rotor device, the main structure of which is made of insulating material and has metal conductors embedded in it. The external component is an energized spiral coil used to provide a magnetic field. The rotor device is mounted on the steering axle of the front wheel of the electric vehicle.

6. The device for warning electric vehicles turning and changing lanes according to claim 1, characterized in that: The formula for calculating the regulating current is: In the formula F 阻尼力 For the required damping, B is the magnetic induction intensity, μ is the permeability, N is the number of turns of the coil, I is the adjustment current, R is the radius of the annular energized spiral coil in the magnetic damper, z is the perpendicular distance from the measuring point to the central axis of the ring, A is the cross-sectional area of ​​the conductor, d is the thickness of the conductor, σ is the conductivity of the conductor, L is the length of the metal conductor on the rotor, and n is the number of metal conductors on the rotor.

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