A new energy vehicle safe and energy-saving driving assistance device and auxiliary driving method

Abstract

The present invention proposes a safe and energy-saving driving assistance device and an assisted driving method for new energy vehicles. The driving assistance device includes an accelerator pedal sensor, a brake pedal sensor, a driving assistance control unit, a forward sensing module, a vehicle speed sensor, an electric drive controller and an assisted driving function switch. The accelerator pedal sensor, the brake pedal sensor and the vehicle speed sensor are hard-wired to the assisted driving control unit respectively, and the forward sensing module and the electric drive controller are connected to the assisted driving control unit via a CAN line. The present invention controls the electric drive and electric brake torque of the new energy vehicle drive system by sensing the distance and speed of the stationary or moving vehicle or other obstacles in front of the vehicle, which is used to help the driver reasonably control the vehicle speed and distance when driving, reduce the risk of collision, and reduce the energy consumption loss caused by frequent acceleration, deceleration and braking, and improve the vehicle's cruising range on actual roads.

Description

Technical Field

[0001] The present invention relates to the technical field of safe and energy-saving assisted driving of new energy vehicles, and in particular to a safe and energy-saving driving auxiliary device and an assisted driving method for new energy vehicles. Background Art

[0002] When drivers are driving on actual roads, they often fail to control the distance between vehicles, which leads to safety accidents such as collisions with vehicles in front of them or other obstacles. Different drivers have large differences in power consumption when driving on actual roads. The main reason is the difference in driving habits and driving proficiency. Unskilled drivers cannot predict the distance to the vehicle or obstacle in front of them, which prompts them to frequently accelerate and decelerate and brake deeply, resulting in loss of driving efficiency and mechanical brake friction energy loss, which in turn leads to high power consumption.

[0003] To this end, the present invention has designed a safe and energy-saving driving assistance system, which assists the driver in controlling the driving acceleration and motor recovery torque through distance and speed detection, thereby improving safety while reducing the energy consumption of the entire vehicle. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention designs a safe and energy-saving driving assistance device and an assisted driving method for new energy vehicles, which are suitable for pure electric vehicles or other types of new energy vehicles with motor-driven driving. By sensing the distance and speed of stationary or moving vehicles or other obstacles in front of the vehicle, the electric drive and electric braking torque of the new energy vehicle drive system are controlled to help the driver reasonably control the vehicle speed and distance while driving, reduce the risk of collision, reduce energy consumption caused by frequent acceleration, deceleration and braking, and improve the vehicle's range on actual roads.

[0005] In order to achieve the above-mentioned objectives, on the one hand, the present invention proposes a safe and energy-saving driving assistance device for new energy vehicles, including an accelerator pedal sensor, a brake pedal sensor, a driving assistance control unit, a forward sensing module, a vehicle speed sensor, an electric drive controller and an assisted driving function switch. The accelerator pedal sensor, the brake pedal sensor, and the vehicle speed sensor are hard-wired to the assisted driving control unit respectively, and the forward sensing module, the electric drive controller and the assisted driving control unit are connected via a CAN line.

[0006] The accelerator pedal sensor and the brake pedal sensor are used to respectively collect the opening degrees of the accelerator pedal and the brake pedal operated by the driver;

[0007] The forward sensing module is responsible for continuously measuring the distance between the vehicle and the vehicle in front, and calculating the relative speed according to the change in the distance;

[0008] The vehicle speed sensor is used to detect the vehicle speed and send the real-time vehicle speed to the forward sensing module;

[0009] The driving assistance control unit is used to calculate according to the current vehicle distance and a pre-stored calculation formula;

[0010] The whole vehicle distance and driving safety status are evaluated, and auxiliary driving control is performed by adjusting the vehicle drive and energy recovery torque;

[0011] The assisted driving switch is used for the driver to turn on or off the assisted driving function.

[0012] On the other hand, the present invention also proposes a new energy vehicle safe and energy-saving assisted driving method, comprising the following steps:

[0013] Step S1. Status perception of the vehicle and the vehicle ahead: collecting vehicle status information, including the vehicle speed, accelerator pedal opening, brake pedal opening, distance to the vehicle ahead and relative speed;

[0014] Step S2. Calculate the safe distance and transition distance: The driving assistance control unit calculates the safe distance and transition distance according to the vehicle speed and relative speed;

[0015] Step S3. Vehicle distance safety status assessment: The driving assistance control unit assesses the current vehicle distance safety status according to the relative vehicle speed, the distance to the preceding vehicle, and the calculated safe distance and transition distance;

[0016] Step S4. Driving assistance intervention judgment: when the vehicle is in a transitional close distance state or a dangerous close distance state and AEB is not activated, it is judged that driving assistance intervention is required and the process goes to step S5; otherwise, the process goes to step S6;

[0017] Step S5. Driving assistance intervention: intervening and adjusting the driving torque in the driver driving mode and the motor recovery torque in the deceleration mode;

[0018] Step S6. Driving assistance maintenance judgment: judge whether the vehicle distance safety state is transition distance away or dangerous distance away and AEB is not activated. If so, go to step 7; otherwise, go to step 8;

[0019] Step S7: Driving assistance maintenance: maintaining the driving and regenerative torque adjustment strategies for driving assistance intervention in the current vehicle distance mode;

[0020] Step S8: Exit or do not intervene in energy-saving and safe driving assistance.

[0021] Specifically, in step S2, the driving assistance control unit calculates the safe vehicle distance according to the vehicle speed and the relative vehicle speed. The calculation formula of the safe vehicle distance is:

[0022]

[0023] Among them, Vrel Relative vehicle speed; V r is the vehicle speed; t a Preset constants for driver reaction and brake system response time; a b is the preset constant for the maximum braking deceleration; S0 is the preset constant for the vehicle distance when braking;

[0024] The transition distance is a proportional function of the safety distance, that is:

[0025] S M =k*S S , the ratio k is a constant greater than 1.

[0026] Specifically, the current vehicle distance safety state is evaluated in step S3, and the vehicle distance safety state is divided into six safety states: safe vehicle distance close, transitional vehicle distance close, dangerous vehicle distance close, safe vehicle distance far, transitional vehicle distance far, and dangerous vehicle distance far.

[0027] Specifically, the intervention adjustment of the driving torque in the driver driving mode and the motor recovery torque in the deceleration mode in step S5 is as follows:

[0028] 1) In driving mode, the allowable vehicle driving acceleration limit is calculated based on the difference between the current vehicle distance and the safe vehicle distance, and based on the motor driving torque limit under this limit:

[0029] When the vehicle distance is less than the transition distance and greater than the safety distance, that is, S S <S n ≤S M When the acceleration limit is calculated according to the following formula:

[0030]

[0031]

[0032] Among them, a DM is the maximum acceleration allowed when driving assistance intervenes; a Max The maximum energy recovery intensity requested when driving assistance intervenes; a Min The minimum energy recovery intensity requested when the driver assists intervention;

[0033] According to the limited acceleration a L , calculate the motor drive torque limit

[0034]

[0035] Where m is the mass of the vehicle; g is the acceleration of gravity; f is the rolling friction coefficient; C dis the wind resistance coefficient; A is the frontal area; V is the vehicle speed; R is the tire rolling radius; i0 is the reducer transmission ratio; μ is the transmission coefficient;

[0036] 2) In energy recovery mode, the motor recovery torque curve is automatically matched according to the ratio of the current vehicle distance and the safe vehicle distance:

[0037] 3) In the state of transitional vehicle distance approach and dangerous vehicle distance approach, the motor drive torque limit is calculated according to the set drive acceleration limit, and the energy recovery torque requested for intervention is calculated according to the energy recovery intensity:

[0038] Calculate the expected motor coasting energy recovery torque based on the energy recovery intensity

[0039] When the distance between vehicles is S n Less than the safe distance, that is, S n ≤S S When the drive acceleration limit and energy recovery deceleration are set according to the maximum value, that is:

[0040] a DL =a DM

[0041] a Req =a Max .

[0042] Beneficial effects of the present invention

[0043] The present invention provides a new energy vehicle safe and energy-saving driving assistance system and an assisted driving method, which are applicable to pure electric vehicles or other types of new energy vehicles with motor-driven vehicles. By sensing the distance and speed of a stationary or moving vehicle or other obstacle in front of the vehicle, the electric drive and electric braking torque of the new energy vehicle drive system are controlled to help the driver reasonably control the vehicle speed and distance while driving, reduce the risk of collision, and reduce energy consumption loss caused by frequent acceleration, deceleration and braking, and can effectively improve the vehicle's cruising range on actual roads. At the same time, the present invention can be combined with the automatic emergency braking (AEB) function to further improve the vehicle's driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a structural diagram of a new energy vehicle safety and energy-saving driving assistance system of the present invention;

[0045] Figure 2 This is a flow chart of a new energy vehicle safety and energy-saving auxiliary driving method of the present invention;

[0046] Figure 3 It is a schematic diagram of the division of six types of safe vehicle distance areas in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example: See Figure 1-3 .

[0049] Example 1

[0050] like Figure 1 As shown, a safe and energy-saving driving assistance system for new energy vehicles of the present invention comprises an accelerator pedal sensor 1, a brake pedal sensor 2, a driving assistance control unit 3, a forward sensing module 4, a vehicle speed sensor 5, an electric drive controller 6 and an assisted driving function switch 7. The accelerator pedal sensor 1, the brake pedal sensor 2 and the vehicle speed sensor 5 are respectively connected to the assisted driving control unit 3 by hard wires, and the forward sensing module 4 and the electric drive controller 6 are connected to the assisted driving control unit 7 via a CAN line.

[0051] Specifically, the accelerator pedal sensor 1 and the brake pedal sensor 2 are used to collect the opening degrees of the accelerator pedal and the brake pedal operated by the driver respectively;

[0052] Specifically, the forward sensing module 4 is used to continuously measure the distance between the vehicle and the vehicle in front, and calculate the relative vehicle speed according to the change in the distance;

[0053] Specifically, the vehicle speed sensor 5 is used to detect the vehicle speed and send the real-time vehicle speed to the forward sensing module 4;

[0054] Specifically, the driving assistance control unit 3 is used to calculate according to the current vehicle distance and a pre-stored calculation formula;

[0055] Specifically, the vehicle measures the distance and evaluates the driving safety status, while assisting driving control by adjusting the vehicle drive and energy recovery torque;

[0056] Specifically, the assisted driving switch 7 is used for the driver to turn on or off the assisted driving function.

[0057] like Figure 2 As shown, a new energy vehicle safe and energy-saving assisted driving method comprises the following steps:

[0058] Step S1. Status perception of the vehicle and the vehicle ahead: collecting vehicle status information, including the vehicle speed, accelerator pedal opening, brake pedal opening, distance to the vehicle ahead and relative speed;

[0059] The vehicle speed sensor 5 measures the vehicle speed and acceleration; the accelerator pedal sensor 1 collects the accelerator pedal opening; the brake pedal sensor 2 collects the brake pedal opening; the forward sensing module 4 continuously measures the distance to the preceding vehicle and the relative speed;

[0060] Step S2. Calculate the safe vehicle distance and transition vehicle distance: the driving assistance control unit 3 calculates the safe vehicle distance and transition vehicle distance according to the vehicle speed and relative vehicle speed;

[0061] a. Calculate the safe distance based on the vehicle speed and relative speed:

[0062]

[0063] Among them, V rel is the relative vehicle speed; V r is the vehicle speed; ta is the preset constant for the driver's reaction and braking system response time; a b is the preset constant for the maximum braking deceleration; S0 is the preset constant for the vehicle distance when braking (the preset constant for automatically matching the safe vehicle distance calculation formula according to the three driving modes of economy, normal and sports selected by the driver);

[0064] b. Calculate the transition distance:

[0065] S M =k*S S , the ratio k is a constant greater than 1.

[0066] For example, the current vehicle speed is 120km / h, or 33.3m / s, and the relative vehicle speed is 10km / h, or 2.77m / s;

[0067] Setting a is 1.2s, a b 6m / s 2 , S0 is 2m, k is 1.3, then the safe distance S is calculated S is 57m; transition distance S M It is 74m.

[0068] Step S3. Vehicle distance safety state assessment: The driving assistance control unit 3 assesses the current vehicle distance safety state according to the detected relative vehicle speed, the distance to the preceding vehicle, and the calculated safe distance and transition distance, and divides the current vehicle distance safety state into six safety states: safe distance close, transition distance close, dangerous distance close, safe distance far, transition distance far, and dangerous distance far;

[0069] For example, the collision time between the two vehicles is calculated by dividing the distance between the two vehicles by the relative speed as the standard for evaluating the current safety status of the vehicle distance. Assuming that the relative speed of the two vehicles is 10km / h and the current distance is 80m, the driving safety state is close to the safe distance; if the current distance is 70m, the driving safety state is close to the transitional distance; if the current distance is 40m, the driving safety state is close to the dangerous distance; conversely, assuming that the relative speed of the two vehicles is -10km / h and the current distance is 80m, the driving safety state is far from the safe distance; if the current distance is 70m, the driving safety state is far from the transitional distance; if the current distance is 40m, the driving safety state is close to the dangerous distance.

[0070] Step S4. Driving assistance intervention judgment: when the vehicle is in a transitional close distance state or a dangerous close distance state and AEB is not activated, it is judged that driving assistance intervention is required and the process goes to step S5; otherwise, the process goes to step S6;

[0071] Step S5. Driving assistance intervention: intervening and adjusting the driving torque in the driver's driving mode (pressing the accelerator pedal) and the motor recovery torque in the deceleration mode (releasing the accelerator pedal to coast or pressing the brake pedal to brake);

[0072] Step S6. Driving assistance maintenance judgment: judge whether the vehicle distance safety state is transition distance away or dangerous distance away and AEB is not activated. If so, go to step 7; otherwise, go to step 8;

[0073] Step S7: Driving assistance maintenance: maintaining the driving and regenerative torque adjustment strategies for driving assistance intervention in the current vehicle distance mode;

[0074] Step S8: Exit or do not intervene in energy-saving and safe driving assistance.

[0075] As a preferred embodiment, in step S5, the driving assistance intervention refers to: intervening and adjusting the driving torque in the motor driver driving mode (pressing the accelerator pedal) and the motor recovery torque in the deceleration mode (releasing the accelerator pedal to coast or pressing the brake pedal to brake). Specifically, it includes:

[0076] s51. In driving mode, the allowable vehicle driving acceleration limit is calculated according to the current vehicle distance, transition vehicle distance, and safety vehicle distance, and the driving torque is limited according to the limit;

[0077] When the vehicle distance is less than the transition distance and greater than the safety distance (i.e. S S <S n ≤S M ), the acceleration limit is calculated according to the following formula:

[0078]

[0079]

[0080] Among them, a DM is the maximum acceleration allowed when driving assistance intervenes; a Max The maximum energy recovery intensity requested when the driver assists, usually set to 0.3g; a Min The minimum energy recovery intensity requested when the driver assists intervention;

[0081] And according to the limited acceleration a L , calculate the motor drive torque limit:

[0082]

[0083] Where m is the mass of the vehicle; g is the acceleration of gravity; f is the rolling friction coefficient; C d is the drag coefficient; A is the frontal area; V is the vehicle speed; R is the tire rolling radius; i0 is the reducer transmission ratio; μ is the transmission coefficient.

[0084] s52. In energy recovery mode, the motor recovery torque curve is automatically matched according to the current vehicle distance, transition vehicle distance and safety vehicle distance;

[0085] s53. In the transitional vehicle-to-vehicle close distance and dangerous vehicle-to-vehicle close distance states, the driving torque limit is calculated according to the set driving acceleration limit, and the energy recovery intensity is calculated to calculate the energy recovery torque requested to intervene.

[0086] According to the energy recovery intensity, calculate the expected motor coasting energy recovery torque:

[0087]

[0088] When the distance between vehicles is S n Less than the safe distance (S n ≤S S ), the drive acceleration limit and energy recovery deceleration are set according to the maximum value, that is:

[0089] a DL =a DM

[0090] a Req =a Max .

[0091] The following example illustrates the calculation process of the drive torque limit and energy recovery torque:

[0092] Assume a DM Set to 3m / s 2 , a Max Set to 0.3g, a Min Set to 0.15g

[0093] When the vehicle distance is less than the transition distance and greater than the safety distance (i.e. S S <S n ≤S M ), the calculation results of the driving acceleration limit and energy recovery deceleration are shown in Table 1 below:

[0094] Table 1 Driving acceleration limit and energy recovery deceleration (S S <S n ≤S M )

[0095]

[0096] When the distance between vehicles is S n Less than the safe distance (S n ≤S S ), the calculation results of the driving acceleration limit and energy recovery deceleration are shown in Table 2 below:

[0097] Table 2 Driving acceleration limit and energy recovery deceleration (S n ≤S S )

[0098]

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A new energy vehicle safety and energy-saving driving assistance device, characterized in that: It includes an accelerator pedal sensor, a brake pedal sensor, a driving assistance control unit, a forward sensing module, a vehicle speed sensor, an electric drive controller and an assisted driving function switch, wherein the accelerator pedal sensor, the brake pedal sensor and the vehicle speed sensor are hard-wired to the assisted driving control unit respectively, and the forward sensing module and the electric drive controller are connected to the assisted driving control unit via a CAN line; The accelerator pedal sensor and the brake pedal sensor are used to respectively collect the opening degrees of the accelerator pedal and the brake pedal operated by the driver; The forward sensing module is responsible for continuously measuring the distance between the vehicle and the vehicle in front, and calculating the relative speed according to the change in the distance; The vehicle speed sensor is used to detect the vehicle speed and send the real-time vehicle speed to the forward sensing module; The driving assistance control unit is used to calculate the safe vehicle distance and evaluate the driving safety status according to the current vehicle distance and the pre-stored calculation formula, and to perform auxiliary driving control by adjusting the vehicle drive and energy recovery torque; The assisted driving switch is used for the driver to turn on or off the assisted driving function; The auxiliary driving method of the new energy vehicle safety and energy-saving driving auxiliary device comprises the following steps: Step S1. Status perception of the vehicle and the vehicle ahead: collecting vehicle status information, including the vehicle speed, accelerator pedal opening, brake pedal opening, distance to the vehicle ahead and relative speed; Step S2. Calculate the safe distance and transition distance: The driving assistance control unit calculates the safe distance and transition distance according to the vehicle speed and relative speed; Step S3. Vehicle distance safety status assessment: The driving assistance control unit assesses the current vehicle distance safety status according to the relative vehicle speed, the distance to the preceding vehicle, and the calculated safe distance and transition distance; Step S4. Driving assistance intervention judgment: when the vehicle is in a transitional close distance state or a dangerous close distance state and AEB is not activated, it is judged that driving assistance intervention is required and the process goes to step S5; otherwise, the process goes to step S6; Step S5. Driving assistance intervention: intervening and adjusting the driving torque in the driver driving mode and the motor recovery torque in the deceleration mode; Step S6. Driving assistance maintenance judgment: judge whether the vehicle distance safety state is transition distance away or dangerous distance away and AEB is not activated. If so, go to step 7; otherwise, go to step 8; Step S7: Driving assistance maintenance: maintaining the driving and regenerative torque adjustment strategies for driving assistance intervention in the current vehicle distance mode; Step S8. Exit or do not intervene in energy-saving and safe driving assistance; The specific contents of the intervention adjustment of the driving torque in the driver driving mode and the motor recovery torque in the deceleration mode are as follows: 1) In driving mode, the allowable vehicle driving acceleration limit is calculated based on the difference between the current vehicle distance and the safe vehicle distance, and based on the motor driving torque limit under this limit: When the vehicle distance is less than the transition distance and greater than the safety distance, that is, S S n ≤S M When the acceleration limit is calculated according to the following formula:​ Among them, a DM is the maximum acceleration allowed when driving assistance intervenes; a Max The maximum energy recovery intensity requested when driving assistance intervenes; a Min The minimum energy recovery intensity requested when the driver assists the intervention; according to the limited acceleration a L , calculate the motor drive torque limit Where m is the mass of the vehicle; g is the acceleration of gravity; f is the rolling friction coefficient; C d is the wind resistance coefficient; A is the frontal area; V is the vehicle speed; R is the tire rolling radius; i0 is the reducer transmission ratio; μ is the transmission coefficient; 2) In energy recovery mode, the motor recovery torque curve is automatically matched according to the ratio of the current vehicle distance and the safe vehicle distance: 3) In the state of transitional vehicle distance approach and dangerous vehicle distance approach, the motor drive torque limit is calculated according to the set drive acceleration limit, and the energy recovery torque requested for intervention is calculated according to the energy recovery intensity: Calculate the expected motor coasting energy recovery torque based on the energy recovery intensity When the distance between vehicles is S n Less than the safe distance, that is, S n ≤S S When the drive acceleration limit and energy recovery deceleration are set according to the maximum value, that is: a DL =a DM a Req =a Max 。 2. A new energy vehicle safety and energy-saving driving assistance device according to claim 1, characterized in that: In step S2, the driving assistance control unit calculates the safe vehicle distance according to the vehicle speed and the relative vehicle speed. The calculation formula of the safe vehicle distance is: Among them, V rel Relative vehicle speed; V r is the vehicle speed; t a Preset constants for driver reaction and brake system response time; a b is the preset constant for the maximum braking deceleration; S0 is the preset constant for the vehicle distance when braking; The transition distance is a proportional function of the safety distance, that is: S M =k*S S , the ratio k is a constant greater than 1.

3. A new energy vehicle safety and energy-saving driving assistance device according to claim 1, characterized in that: The current vehicle distance safety state is evaluated in step S3, and the vehicle distance safety state is divided into six safety states: safe vehicle distance close, transition vehicle distance close, dangerous vehicle distance close, safe vehicle distance far, transition vehicle distance far, and dangerous vehicle distance far.

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