阅读说明：本技术 一种分布式驱动型电动汽车的控制方法、装置及电动汽车 (Control method and device for distributed driving type electric automobile and electric automobile ) 是由 刘杰 徐卫东 李波 李国红 杜晓丰 李钟男 茹亚超 于 2020-04-28 设计创作，主要内容包括：本发明公开了一种分布式驱动型电动汽车的控制方法、装置及电动汽车,方法包括：获取电动汽车的胎压变化量和当前挡位；根据所述胎压变化量和所述当前挡位,确定是否对所述电动汽车进行稳定性控制；在确定对所述电动汽车进行稳定性控制的情况下,获取车轮的滑移率,车轮的滑移率包括：左前轮对应的第一滑移率,右前轮对应的第二滑移率,左后轮对应的第三滑移率和右后轮对应的第四滑移率；根据车轮的滑移率,对所述电动汽车进行稳定性控制。本发明的方案针对分布式驱动型电动汽车设计了合理的稳定性控制策略,在车轮的胎压在发生剧烈变化时,能够保证车辆的稳定性,提升驾乘感受和安全性。(The invention discloses a control method and a control device for a distributed driving type electric automobile and the electric automobile, wherein the method comprises the following steps: acquiring the tire pressure variation and the current gear of the electric automobile; determining whether to perform stability control on the electric vehicle according to the tire pressure variation and the current gear; in the case of determining to perform stability control on the electric vehicle, obtaining a slip ratio of a wheel, the slip ratio of the wheel including: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel; and performing stability control on the electric automobile according to the slip rate of the wheels. The scheme of the invention designs a reasonable stability control strategy aiming at the distributed driving type electric automobile, and can ensure the stability of the automobile and improve the driving feeling and the safety when the tire pressure of the wheels is changed violently.)

1. A control method of a distributed drive type electric vehicle, characterized by comprising:

acquiring the tire pressure variation and the current gear of the electric automobile;

determining whether to perform stability control on the electric vehicle according to the tire pressure variation and the current gear;

under the condition that the stability control of the electric automobile is determined, obtaining the slip rate of wheels; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

and performing stability control on the electric automobile according to the slip rate of the wheel.

2. The control method of the distributed drive type electric vehicle according to claim 1, wherein acquiring the tire pressure variation amount and the current shift position of the electric vehicle includes:

and when a low-pressure alarm signal sent by the tire pressure monitoring module is received, acquiring the tire pressure variation and the current gear of the electric automobile.

3. The control method of the distributed drive type electric vehicle according to claim 1, wherein determining whether to perform stability control on the electric vehicle according to the tire pressure variation amount and the current shift position of the electric vehicle includes:

if the current gear is a neutral gear and the tire pressure variation is larger than a first threshold, determining whether to perform stability control on the electric automobile according to the current running condition of the electric automobile;

and if the current gear is a neutral gear and the tire pressure variation is smaller than or equal to the first threshold, giving an alarm.

4. The control method of the distributed drive type electric vehicle according to claim 1, wherein whether or not to perform stability control on the electric vehicle is determined in accordance with a tire pressure variation amount and a current shift position of the electric vehicle, further comprising:

and if the current gear is a non-neutral gear and the tire pressure variation is larger than a second threshold value, determining to perform stability control on the electric vehicle.

5. The control method of the distributed drive type electric vehicle according to claim 1, wherein the electric vehicle is subjected to stability control in accordance with a slip ratio of the wheel, further comprising:

determining the current running condition of the electric automobile; wherein the driving condition comprises one of the following: driving working conditions, sliding working conditions and braking working conditions;

and under the current running working condition, carrying out stability control on the electric automobile according to the slip rate of the wheels.

6. The control method of the distributed drive type electric vehicle according to claim 5, wherein the distributed drive type electric vehicle includes an elastic energy accumulator connected to a hub motor of the electric vehicle through a transmission shaft with an electromagnetic clutch interposed therebetween;

before the stability control is performed on the electric vehicle according to the slip ratio of the wheel, the method further includes:

controlling the electromagnetic clutch to disconnect the transmission shaft so as to cut off energy transmission between the elastic energy accumulator and the hub motor;

under the driving working condition, carrying out distribution control on the driving torque of a hub motor of the electric automobile;

and under the braking working condition, the braking torque of the hub motor of the electric automobile is distributed and controlled.

7. The control method of the distributed drive type electric vehicle according to claim 5 or 6, wherein the stability control of the electric vehicle in the running condition according to the slip ratio of the wheel in the driving condition includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so as to enable the first slip ratio to be equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, applying hydraulic braking force to the two rear wheels to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

8. The control method of the distributed drive type electric vehicle according to claim 5, wherein the stability control of the electric vehicle in the running condition according to the slip ratio of the wheel in the braking condition or the coasting condition includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two rear wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

9. A control device of a distributed drive type electric vehicle, characterized by comprising:

the first acquisition module is used for acquiring the tire pressure variation and the current gear of the electric automobile;

the determining module is used for determining whether to perform stability control on the electric automobile according to the tire pressure variation and the current gear of the electric automobile;

the second acquisition module is used for acquiring the slip rate of the wheel under the condition that the stability control of the electric automobile is determined; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

and the first control module is used for performing stability control on the electric automobile according to the slip rate of the wheels.

10. An electric vehicle characterized in that the vehicle includes a processor, a memory, and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the control method of the distributed drive type electric vehicle according to any one of claims 1 to 8 when executing the computer program.

Technical Field

The invention relates to the technical field of automobiles, in particular to a control method and device for a distributed driving type electric automobile and the electric automobile.

Background

The wheel hub driving type distributed pure electric automobile directly drives the vehicle by the driving motor without a speed reducing mechanism, thereby saving the traditional parts such as a transmission shaft and the like, improving the efficiency of a transmission system and being an ideal driving mode of the electric automobile. The hub driving type distributed pure electric vehicle in the current market has no mass production vehicle type and is in a research and development stage.

At present, the traditional tire pressure monitoring module is not linked with an automobile stability control strategy, so that when the tire pressure of a wheel is changed violently, the stability of the vehicle is poor, and the driving feeling and the safety are affected. Therefore, a reasonable stability control strategy needs to be designed for the hub-driven distributed pure electric vehicle, so that the stability of the vehicle is ensured, and the driving feeling and the safety are improved.

Disclosure of Invention

In order to solve the technical problems, the invention provides a control method and a control device for a distributed driving type electric automobile and the electric automobile, and solves the problems that the existing hub driving type distributed pure electric automobile lacks a reasonable stability control strategy, cannot ensure the stability of the automobile, and affects the driving feeling and the safety.

According to a first aspect of the present invention, there is provided a control method of a distributed drive type electric vehicle, the method including:

acquiring the tire pressure variation and the current gear of the electric automobile;

determining whether to perform stability control on the electric vehicle according to the tire pressure variation and the current gear;

under the condition that the stability control of the electric automobile is determined, obtaining the slip rate of wheels; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

and performing stability control on the electric automobile according to the slip rate of the wheel.

Optionally, obtain electric automobile's tire pressure variation and current fender position, include:

and when a low-pressure alarm signal sent by the tire pressure monitoring module is received, acquiring the tire pressure variation and the current gear of the electric automobile.

Optionally, according to the tire pressure variation amount and the current gear of the electric vehicle, it is determined whether to perform stability control on the electric vehicle, including:

if the current gear is a neutral gear and the tire pressure variation is larger than a first threshold, determining whether to perform stability control on the electric automobile according to the current running condition of the electric automobile;

and if the current gear is a neutral gear and the tire pressure variation is smaller than or equal to the first threshold, giving an alarm.

Optionally, according to the tire pressure variation amount and the current gear of the electric vehicle, it is determined whether to perform stability control on the electric vehicle, and the method further includes:

and if the current gear is a non-neutral gear and the tire pressure variation is larger than a second threshold value, determining to perform stability control on the electric vehicle.

Optionally, the stability control of the electric vehicle is performed according to the slip ratio of the wheel, and the method further includes:

determining the current running condition of the electric automobile; wherein the driving condition comprises one of the following: driving working conditions, sliding working conditions and braking working conditions;

and under the current running working condition, carrying out stability control on the electric automobile according to the slip rate of the wheels.

Optionally, the distributed driving electric vehicle includes an elastic energy accumulator, the elastic energy accumulator is connected with a hub motor of the electric vehicle through a transmission shaft, and an electromagnetic clutch is arranged in the middle of the transmission shaft;

before the stability control is performed on the electric vehicle according to the slip ratio of the wheel, the method further includes:

controlling the electromagnetic clutch to disconnect the transmission shaft so as to cut off energy transmission between the elastic energy accumulator and the hub motor;

under the driving working condition, carrying out distribution control on the driving torque of a hub motor of the electric automobile;

and under the braking working condition, the braking torque of the hub motor of the electric automobile is distributed and controlled.

Optionally, under the driving condition, according to the slip ratio of the wheel, performing stability control on the electric vehicle under the driving condition includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so as to enable the first slip ratio to be equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, applying hydraulic braking force to the two rear wheels to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

Optionally, under the braking condition or the coasting condition, according to the slip rate of the wheel, performing stability control on the electric vehicle under the driving condition includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two rear wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

According to a second aspect of the present invention, there is provided a control apparatus of a distributed drive type electric vehicle, the apparatus including:

the first acquisition module is used for acquiring the tire pressure variation and the current gear of the electric automobile;

the determining module is used for determining whether to perform stability control on the electric automobile according to the tire pressure variation and the current gear of the electric automobile;

the second acquisition module is used for acquiring the slip rate of the wheel under the condition that the stability control of the electric automobile is determined; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

and the first control module is used for performing stability control on the electric automobile according to the slip rate of the wheels.

According to a third aspect of the present invention, there is provided an electric vehicle, the vehicle comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the control method of the distributed drive type electric vehicle as described above when executing the computer program.

According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the control method of the distributed drive type electric vehicle described above.

The embodiment of the invention has the beneficial effects that:

in the scheme, the tire pressure variation and the current gear of the electric automobile are obtained; determining whether to perform stability control on the electric vehicle according to the tire pressure variation and the current gear; under the condition that the stability control of the electric automobile is determined, obtaining the slip rate of wheels; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel; and further performing stability control on the electric automobile according to the slip rate of the wheels. The scheme of the invention is a stability control strategy designed for the distributed driving type electric automobile, and when the tire pressure of the wheels is changed violently, the stability of the automobile can be ensured, and the driving feeling and the safety can be improved.

Drawings

FIG. 1 is a schematic diagram of a distributed drive system according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a brake system according to an embodiment of the present invention;

fig. 3 shows one of flowcharts of a control method of the distributed drive type electric vehicle of the embodiment of the invention;

FIG. 4 illustrates a flow chart of fault detection for a distributed drive system of an embodiment of the present invention;

fig. 5 shows a second flowchart of a control method of a distributed drive type electric vehicle according to the embodiment of the invention;

fig. 6 shows a third flowchart of a control method of a distributed drive type electric vehicle according to the embodiment of the invention;

fig. 7 is a fourth flowchart showing a control method of the distributed drive type electric vehicle according to the embodiment of the invention;

fig. 8 is a flowchart showing a fifth control method of the distributed drive type electric vehicle according to the embodiment of the invention;

fig. 9 is a schematic configuration diagram of a control device for a distributed drive electric vehicle according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

First, the structure of the distributed drive type electric vehicle will be described with reference to fig. 1 to 2.

As shown in fig. 1, the distributed drive type electric vehicle includes: a first hub motor with brake assembly 11 arranged in the left front wheel hub; a second hub motor with brake assembly 12 disposed within the right front wheel hub; a third hub motor with brake assembly 13 disposed within the left rear wheel hub; a fourth hub motor belt brake assembly 14 disposed within the right rear wheel hub; the vehicle control unit VCU is electrically connected with the first hub motor belt brake assembly 11, the second hub motor belt brake assembly 12, the third hub motor belt brake assembly 13 and the fourth hub motor belt brake assembly 14 respectively so as to transmit control signals;

further, as an implementation manner, as shown in fig. 2, the braking system structure of the distributed drive type electric vehicle specifically includes: the distributed drive system shown in fig. 1, further comprising:

and the electronic stability control module 5 is connected with the first hub motor belt brake assembly 11, the second hub motor belt brake assembly 12, the third hub motor belt brake assembly 13 and the fourth hub motor belt brake assembly 14 through brake pipelines respectively.

A first wheel speed sensor 61 disposed on a left front wheel (LF); a second wheel speed sensor 62 disposed on the right front wheel (RF); a third wheel speed sensor 63 disposed on the left rear wheel (LR); a fourth wheel speed sensor 64 disposed on the right rear wheel (RR); the first wheel speed sensor 61, the second wheel speed sensor 62, the third wheel speed sensor 63 and the fourth wheel speed sensor 64 are respectively connected with the electronic stability control module 5 through hard wires, so that the collected wheel speed signals are transmitted to the electronic stability control module 5.

Electric control booster area braking master cylinder 7, electric control booster area braking master cylinder 7 through the hard line with vehicle control unit 10 is connected to through the brake pipe with electronic stability control module 5 is connected, compares in vacuum booster, and electric control booster can be more accurate control hydraulic braking process, is favorable to improving control accuracy.

The brake pedal 8 and the accelerator pedal 9 are fixed on the periphery of a front panel of a vehicle body cab through bolts, and a displacement sensor 81 on the brake pedal 8 is fixed on the brake pedal through bolts and used for feeding back the shape and stroke change of the brake pedal 8 so as to reflect the braking intention of a driver. The electric control booster with a master cylinder 7 is connected with a brake pedal 8 through a bolt. The displacement sensor 81 connected to the brake pedal 8 and the angle sensor connected to the accelerator pedal 9 are used for acquiring an accelerator pedal signal and a brake pedal signal, and feeding back the acquired signals to the vehicle controller 10.

The steering wheel 15 is provided with a corner sensor, the corner sensor is connected with the steering wheel 15 through a steering column, when the steering wheel 15 rotates, the steering column is driven to rotate, a corner measuring signal of the steering wheel is output through the corner sensor, the corner sensor is electrically connected with the vehicle control unit 10, and the corner measuring signal of the steering wheel is input to the vehicle control unit 10.

As shown in fig. 3, an embodiment of the present invention provides a control method of a distributed drive type electric vehicle, the method including:

step 31, acquiring the tire pressure variation and the current gear of the electric automobile:

the manner of acquiring the tire pressure variation includes, but is not limited to, the entire vehicle controller periodically acquiring from the tire pressure monitoring module, or the tire pressure monitoring module periodically transmitting to the entire vehicle controller 10.

Step 32: determining whether to perform stability control on the electric vehicle according to the tire pressure variation and the current gear;

step 33: under the condition that the stability control of the electric automobile is determined, obtaining the slip rate of wheels; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

step 34: and performing stability control on the electric automobile according to the slip rate of the wheel.

In the embodiment, whether the electric vehicle is subjected to stability control is determined by acquiring the tire pressure variation and the current gear of the electric vehicle and according to the tire pressure variation and the current gear; under the condition that the stability control of the electric automobile is determined, obtaining the slip rate of wheels; and further performing stability control on the electric automobile according to the slip rate of the wheels so as to keep the vehicle stable. The stability control strategy designed for the distributed driving type electric automobile realizes linkage control of tire pressure monitoring and automobile stability control strategies, can effectively guarantee the stability of the automobile when the tire pressure of the wheels is changed violently, and improves driving feeling and safety.

It should be noted that, as an implementation manner, the method embodiment described above can be applied to the distributed drive system type electric vehicle shown in fig. 1 to 2, and is not limited thereto.

Further, before the step 31, the method further includes:

and after the vehicle is powered on, controlling the distributed drive type electric automobile to carry out fault detection.

Specifically, fig. 4 shows a detection flow of the fault detection. After completion and passing of the test, the vehicle enters a ready and drive mode. As shown in fig. 4, the detection process includes:

step 41, powering on the vehicle;

step 42, passing the self-check of the system;

step 43, judging whether the system has abnormal phenomena, if the system is normal, then proceeding to step 44; if the system is judged to be abnormal, step 46 is performed;

step 44, respectively judging whether the accelerator pedal signal, the brake pedal signal and the gear signal are normal, and if the accelerator pedal signal, the brake pedal signal and the gear signal are all normal, further performing step 45 when judging that the accelerator pedal signal, the brake pedal signal and the gear signal have changed signals; if one or more of the accelerator pedal signal, the brake pedal signal and the gear signal are judged to be abnormal, judging that a system fault occurs, and performing step 46;

step 45, entering a driving mode;

and step 46, giving an alarm prompt, lighting an alarm lamp and exiting the program.

In the embodiment, before stability control is carried out, system fault detection is carried out, so that the accuracy of an accelerator pedal signal, a brake pedal signal and a gear signal is effectively ensured, and the accuracy of control is favorably improved.

In an optional embodiment of the present invention, the step 31 may include:

and when a low-pressure alarm signal sent by the tire pressure monitoring module is received, acquiring the tire pressure variation and the current gear of the electric automobile.

In this embodiment, as shown in fig. 1, the tire pressure monitoring modules are respectively arranged and mounted on the tires of each wheel for monitoring the amount of change in the tire pressure of each tire. When the tire pressure monitoring module finds that the tire pressure of the wheel is changed violently and exceeds a certain limit value, a low-pressure alarm signal is sent to the whole vehicle controller 10, and when the whole vehicle controller 10 receives the low-pressure alarm signal, the tire pressure change quantity and the current gear of the electric vehicle are obtained. In this embodiment, through increasing tire pressure monitoring module at the wheel end, realize the tire pressure situation of change of real-time detection each tire, report to the police through low pressure signal when tire pressure changes, can effectively guarantee driving safety.

In an optional embodiment of the present invention, the step 32 includes:

if the current gear is a neutral gear N and the tire pressure variation (in fig. 5, the tire pressure reduction variation Δ) is greater than a first threshold value A, determining whether to perform stability control on the electric vehicle according to the current running condition of the electric vehicle;

specifically, as shown in fig. 5, when the current gear is a neutral gear N and the tire pressure variation is greater than a first threshold a, determining whether to perform stability control on the electric vehicle according to the current driving condition of the electric vehicle includes:

when the electric automobile is in a sliding working condition, determining to perform stability control on the electric automobile;

when the electric automobile is in the parking working condition, the alarm prompt is carried out so as to draw the attention of a driver and supplement pressure to the tire in time.

The current running condition of the electric automobile can be determined according to the speed information and the deceleration information of the electric automobile. Specifically, if the vehicle speed is 0 and the deceleration is 0, it is determined that the electric vehicle is in a stopped state (parking state); and if the vehicle speed is not 0 and the deceleration is not 0, determining that the electric vehicle is in the sliding state.

And if the current gear is a neutral gear and the tire pressure variation is smaller than or equal to the first threshold, giving an alarm prompt to draw the attention of a driver and timely supplementing pressure to the tire.

In the embodiment, when the vehicle is in the neutral position N and the tire pressure is changed violently, the alarm is given when the vehicle is in the parking state, so that a user can master the tire pressure state of the vehicle in time, and the safety risk is avoided; when the vehicle is in the sliding working condition, the stability of the vehicle is controlled by timely starting, so that the stable running of the vehicle is ensured, and the driving condition of stable running is provided for the safe parking of the vehicle.

In an alternative embodiment of the present invention, as shown in fig. 5, the step 32 further includes:

and if the current gear is a non-neutral gear and the tire pressure variation is larger than a second threshold value H, determining to perform stability control on the electric vehicle. Wherein the first threshold a and the second threshold H are scalar quantities, which can be considered as constants;

and if the current gear is a non-neutral gear and the tire pressure variation is smaller than or equal to a second threshold value H, continuously monitoring the tire pressure variation condition and exiting the program.

In this embodiment, when the vehicle is in a non-neutral driving state and the tire pressure variation is detected to be greater than the second threshold H, it is determined that the tire pressure has changed drastically, which will affect the stable operation of the vehicle, and it is determined that the vehicle needs to be subjected to stability control, so that the stable operation of the vehicle is ensured, and a stable operation driving condition is provided for the safe parking of the vehicle.

Further, the step 34 includes:

determining the current running condition of the electric automobile; wherein the driving condition comprises one of the following: driving working conditions, sliding working conditions and braking working conditions;

and under the current running working condition, carrying out stability control on the electric automobile according to the slip rate of the wheels.

Specifically, the determining the current driving condition of the electric vehicle includes:

and determining the current running condition of the electric automobile according to the opening degree signal and the braking signal of the accelerator pedal.

Specifically, as shown in fig. 6, the step of determining the current driving condition of the electric vehicle may include:

step 61, acquiring an accelerator pedal opening signal, judging whether the accelerator pedal opening signal is greater than a first limit value b, and entering an acceleration process stability control mode if the accelerator pedal opening signal is greater than the first limit value b; if the accelerator pedal opening degree signal is less than or equal to the first limit value b, performing step 62;

wherein the first limit b belongs to a standard quantity, which can be regarded as a constant, generally between 0 and 1.

Step 62, judging whether the braking signal is triggered; if the trigger braking signal is judged, stability control is carried out in the braking process; and if the braking signal is not triggered, entering stability control in the sliding process.

In the above embodiment, the current driving condition of the electric automobile is determined according to the opening signal and the braking signal of the accelerator pedal, so that the vehicle under the current working condition is subjected to stability control in a targeted manner, and the control efficiency of the stability control is improved.

Further, in an optional embodiment of the present invention, at least one of the first hub motor belt brake assembly 11, the second hub motor belt brake assembly 12, the third hub motor belt brake assembly 13, and the fourth hub motor belt brake assembly 14 of the distributed drive type electric vehicle is connected to an energy storage component, so that when the vehicle is in a braking energy recovery state, the braking energy can be recovered and stored in the energy storage component, thereby increasing the degree of recovering the braking energy of the entire vehicle, and thus improving the efficiency of recovering the braking energy. When the vehicle is in a driving state, the energy in the energy storage component can be released for providing part of the driving torque; and the vehicle control unit is electrically connected with the energy storage component to transmit a control signal.

Specifically, the energy storage part that distributed drive electric automobile includes is the elasticity energy storage ware, the elasticity energy storage ware pass through the transmission shaft with electric automobile's in-wheel motor connects, be equipped with electromagnetic clutch in the middle of the transmission shaft.

As shown in fig. 1 to 2, as an implementation manner, a first elastic energy storage device 21 is connected to a first in-wheel motor band brake assembly 1 of a left front wheel of a vehicle, and the first elastic energy storage device 21 is connected to the first in-wheel motor band brake assembly 11 through a first transmission shaft 41; and a first electromagnetic clutch 31 for switching the working state of the first elastic energy accumulator 21, wherein the first electromagnetic clutch 31 is disposed between the first transmission shafts 41 and is connected with the vehicle control unit 10 (the connection relationship between the first electromagnetic clutch 31 and the vehicle control unit 10 is not shown in fig. 2). A second elastic energy storage device 22 is connected to a second hub motor belt brake assembly 2 of the right front wheel of the vehicle, and the second elastic energy storage device 22 is connected with the second hub motor belt brake assembly 12 through a second transmission shaft 42; and a second electromagnetic clutch 32 for switching the working state of the second elastic energy storage 22, wherein the second electromagnetic clutch 32 is disposed between the second transmission shafts 42 and connected with the vehicle control unit 10 (the connection relationship between the second electromagnetic clutch 32 and the vehicle control unit 10 is not shown in fig. 2). When braking or driving is needed, the first electromagnetic clutch 31 and the first transmission shaft 41 and the second electromagnetic clutch 32 and the second transmission shaft 42 can be selectively controlled to enable the kinetic energy transmission link (the first transmission shaft 41) of the first hub motor belt brake assembly 11 and the first elastic energy accumulator 21 and the kinetic energy transmission link (the second transmission shaft 42) of the second hub motor belt brake assembly 12 and the second elastic energy accumulator 22 to be connected, and energy transmission is achieved. Under the braking working condition, the elastic energy storage device can be controlled to recover and store part of braking energy into elastic potential energy; and under the driving working condition, the elastic potential energy stored in the elastic energy accumulator is released to provide partial driving force. Therefore, the energy recovery efficiency can be effectively improved, the energy consumption of the power battery pack is reduced, and the driving range of the whole vehicle is favorably increased.

Based on the above embodiment, before step 34, the method further includes:

controlling the electromagnetic clutch to disconnect the transmission shaft so as to cut off energy transmission between the elastic energy accumulator and the hub motor;

under the driving working condition, carrying out distribution control on the driving torque of a hub motor of the electric automobile;

and under the braking working condition, the braking torque of the hub motor of the electric automobile is distributed and controlled.

In this embodiment, when the tire pressure is changed drastically and the stability of the vehicle is determined to be controlled, in order to ensure driving safety, the energy transmission between the elastic energy storage device and the hub motor should be cut off first; furthermore, in order to ensure the driving stability, the driving torque under the driving working condition is subjected to distribution control, and the braking torque under the braking working condition is subjected to distribution control, so that the driving wheels of the vehicle obtain balanced driving force or braking force, and the stable control of the vehicle is realized.

The acceleration process stability control, the braking process stability control, and the coasting process stability control will be described with reference to fig. 7 and 8.

Acceleration process stability control (driving condition)

In an alternative embodiment of the present invention, in the driving condition, the step 34 includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so as to enable the first slip ratio to be equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, applying hydraulic braking force to the two rear wheels to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

In the embodiment, under the driving working condition, according to the slip rates of the four wheels and the slip rates of the front axle and the rear axle, the braking torque is properly applied to the wheels corresponding to the front axle and the rear axle, the slip rates of the wheels are ensured to be consistent, and the driving stability of the vehicle is ensured.

Specifically, taking a wheel with a tire pressure that changes drastically as a right rear wheel (RR wheel) as an example, stability control under a driving condition is described, referring to fig. 7, which mainly includes the following steps:

step 71, if the opening degree signal of the accelerator pedal is greater than a first limit value b, determining to enter the stability control of the acceleration process;

step 72, performing driving force distribution;

for example, in the acceleration process stability control, assuming that the wheel whose tire pressure drastically changes is the right rear wheel (RR wheel), performing the drive force distribution control may include: the driving torque of the in-wheel motor of the RR wheel is controlled to be increased, and the driving torque of the in-wheel motor of the left rear wheel (LR wheel) is controlled to be decreased, so that the vehicle is kept stable.

Step 73, performing a Traction Control System (TCS) Control strategy for the single wheel; in the single-wheel traction control process, the wheel speeds of two coaxial wheels are greatly different, namely the rotation angular speeds of the two coaxial wheels are different, and for a distributed driving vehicle, the vehicle is in an unstable state, so that stability control is needed to be carried out on the wheels, and the specific stability control can comprise the following steps:

step 731, obtaining the slip rates λ i of the two wheels of the front axle, and judging whether the slip rates λ i of the two wheels of the front axle are equal; if not, go to step 732;

step 732, determining whether the slip ratio λ LF of the left front wheel is greater than the slip ratio λ RF of the right front wheel; if so, applying hydraulic braking force to the left front wheel;

step 733, obtaining the slip ratios lambada i of two wheels of the rear axle, and judging whether the slip ratios lambada i of the two wheels of the rear axle are equal; if not, go to step 734;

step 734, determining whether the slip ratio λ LR of the left rear wheel is greater than the slip ratio λ RR of the right rear wheel; if so, applying hydraulic braking force to the left rear wheel;

step 735, judging whether the slip rates of the two wheels of the front axle are equal to the slip rates of the two wheels of the rear axle under the condition that the slip rates of the two wheels of the front axle are equal and the slip rates of the two wheels of the rear axle are equal; if the vehicle speed is equal to the set speed, determining that the vehicle is in a stable working condition in the driving process; if not, go to step 736;

step 736, judging whether the slip rates of the two wheels of the front axle are larger than the slip rates of the two wheels of the rear axle; if so, applying hydraulic braking force to two wheels of the front axle; if not, hydraulic braking force is applied to the rear axle.

In the embodiment, when the pressure of the RR tire is changed severely, the driving torque of the RR wheel is increased properly, the driving torque of the LR wheel is reduced, so that the slip rates of two wheels of a rear shaft are consistent, a proper torsional torque (around the mass center of the automobile) is generated by controlling and adjusting the rear wheel, a leftward torque is generated, a proper braking torque is applied to the left front wheel, the leftward torque is further increased, and the stability of the automobile is enhanced.

(II) braking process stability control and coasting process stability control

In an alternative embodiment of the present invention, in the braking condition or the coasting condition, the step 34 includes:

if the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

if the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to the left front wheel so that the first slip ratio is equal to the second slip ratio;

if the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

if the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, if the first slip ratio is larger than the third slip ratio, controlling to apply hydraulic braking force to the two rear wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal; and if the first slip ratio is smaller than the third slip ratio, controlling to apply hydraulic braking force to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

In this embodiment, when the deviation between the first slip ratio and the second slip ratio exceeds a predetermined range, it is determined that the first slip ratio is not equal to the second slip ratio, and when the deviation between the third slip ratio and the fourth slip ratio exceeds a predetermined range, it is determined that the third slip ratio is not equal to the fourth slip ratio. And under the condition that the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, when the deviation between the first slip ratio and the third slip ratio exceeds a preset range, determining that the first slip ratio is not equal to the third slip ratio, namely the slip ratios of the front shaft and the rear shaft are not equal. According to the embodiment, under the braking working condition or the sliding working condition, the braking torque is properly applied to the wheels corresponding to the front axle and the rear axle according to the slip rates of the four wheels and the slip rates of the front axle and the rear axle, so that the slip rates of the wheels are consistent, and the driving stability of the vehicle is ensured.

Specifically, taking a wheel with a tire pressure that changes drastically as a right rear wheel (RR wheel) as an example, stability control under a braking condition or a coasting condition is introduced, please refer to fig. 8, which mainly includes the following steps:

step 81, if the triggering of a brake pedal signal is detected, determining to enter the stability control of the braking process;

step 82, braking force distribution is carried out;

step 83, performing an Automatic anti-lock braking system (ABS) control strategy for a single wheel; during the anti-lock braking control, the wheel speeds of the two coaxial wheels are greatly different, that is, the rotation angular speeds of the two coaxial wheels are different, and for a distributed driving vehicle, the vehicle will be in an unstable state, and therefore stability control is required to be performed on the wheels, and specifically, the stability control may include the following steps:

step 831, obtaining the slip ratios λ i of the two wheels of the front axle, and judging whether the slip ratios λ i of the two wheels of the front axle are equal; if not, go to step 832;

step 832, judging whether the slip ratio lambda LF of the left front wheel is greater than the slip ratio lambda RF of the right front wheel; if so, applying hydraulic braking force to the right front wheel;

step 833, obtaining the slip rates λ i of the two wheels of the rear axle, and judging whether the slip rates λ i of the two wheels of the rear axle are equal; if not, go to step 834;

834, judging whether the slip ratio lambda LR of the left rear wheel is larger than the slip ratio lambda RR of the right rear wheel; if so, applying hydraulic braking force to the right rear wheel;

step 835, judging whether the slip rates of the two wheels of the front axle are equal to the slip rates of the two wheels of the rear axle or not under the condition that the slip rates of the two wheels of the front axle are equal and the slip rates of the two wheels of the rear axle are equal; if the brake conditions are equal, determining that the vehicle is in a stable working condition in the braking process; if not, go to step 836;

step 836, judging whether the slip rates of the two wheels of the front axle are greater than the slip rates of the two wheels of the rear axle; if so, applying a hydraulic braking force to two wheels of the rear axle; if not, a hydraulic braking force is applied to the two wheels of the front axle.

In the embodiment, when the slip rates of the two coaxial wheels have deviation and the deviation exceeds a preset range, the hydraulic braking intervention is controlled to be carried out on the vehicle with the small slip rate until the slip rates, namely the rotation rates of the two coaxial wheels are kept in a reasonable range. Specifically, firstly, judging whether the slip rates of the wheels of the two front axles are the same, if so, indicating that the rotation angular speeds of the two wheels of the front axles are the same, and indicating that the wheels do not lose stability in the braking process when running according to a set route; similarly, whether the slip rates of the wheels of the two rear axles are the same or not is judged, if yes, the rotation angular speeds of the two wheels of the rear axles are consistent, and the situation that the wheels do not lose stability in the braking process when the wheels run according to the set route is shown. And further, judging the slip rates of the front and rear shafts, and if the slip rates of the front and rear shafts are consistent, indicating that the stability control of the vehicle is good in the braking control process and the program is finished. When there is a deviation in the slip rates of the wheels of the front and rear axles, which exceeds a preset allowable range, it is necessary to perform hydraulic braking intervention on the two wheels of the axle having a small slip rate until the slip rates, i.e., the rotation rates, of the wheels of the front and rear axles are maintained within a reasonable range. According to the embodiment, the intervention and modulation of the hydraulic braking torque is carried out on the wheels with low slip rates, so that the slip rate deviation of each wheel is kept within the preset range, wherein the preset range is a standard quantity, the stable running of the vehicle can be effectively guaranteed under the condition that the tire pressure is changed violently, the prerequisite condition is provided for the maintenance of safe parking, and the running safety is guaranteed.

In the above embodiment, when the tire pressure is changed drastically, the driving torque or the braking torque of each wheel is controlled appropriately according to the slip ratio of the wheel, so that a reasonable rotation torque is formed, and the stable control of the vehicle is realized. When the tire pressure changes violently, stability control is carried out on the vehicle, so that safe and effective vehicle speed reduction is achieved, different energy recovery combination strategies are reasonably selected, the energy recovery efficiency is improved, and conditions are provided for improving the system safety in the driving process.

Corresponding to the method embodiment, the embodiment of the invention also provides a control device of the distributed driving type electric automobile.

As shown in fig. 9, in an embodiment of the present invention, a control device for a distributed drive type electric vehicle, the device 900 includes:

a first obtaining module 901, configured to obtain a tire pressure variation and a current gear of an electric vehicle;

a determining module 902, configured to determine whether to perform stability control on an electric vehicle according to a tire pressure variation and a current gear of the electric vehicle;

a second obtaining module 903, configured to obtain a slip ratio of a wheel when it is determined that the stability of the electric vehicle is controlled; the slip ratio of the wheel includes: a first slip ratio corresponding to the left front wheel, a second slip ratio corresponding to the right front wheel, a third slip ratio corresponding to the left rear wheel and a fourth slip ratio corresponding to the right rear wheel;

the first control module 904 is configured to perform stability control on the electric vehicle according to a slip ratio of a wheel.

Optionally, the first obtaining module 901 includes:

the first acquisition submodule is used for acquiring the tire pressure variation and the current gear of the electric automobile when receiving a low-pressure alarm signal sent by the tire pressure monitoring module.

Optionally, the determining module 902 includes:

the first determining submodule is used for giving an alarm prompt when the current gear is neutral and the tire pressure variation is larger than a first threshold value;

and the second determining submodule is used for determining that the electric automobile is subjected to stability control when the current gear is a non-neutral gear and the tire pressure variation is larger than a second threshold value or the current gear is a neutral gear and the tire pressure variation is smaller than or equal to the first threshold value.

Optionally, the first control module 904 further includes:

the third determining submodule is used for determining the current running condition of the electric automobile; wherein the driving condition comprises one of the following: driving working conditions, sliding working conditions and braking working conditions;

and the first control submodule is used for performing stability control on the electric automobile according to the slip rate of the wheels under the current running working condition.

Optionally, the distributed driving electric vehicle includes an elastic energy accumulator, the elastic energy accumulator is connected with a hub motor of the electric vehicle through a transmission shaft, and an electromagnetic clutch is arranged in the middle of the transmission shaft;

the device further comprises:

the second control module is used for controlling the electromagnetic clutch to disconnect the transmission shaft so as to cut off energy transmission between the elastic energy accumulator and the hub motor;

the third control module is used for carrying out distribution control on the driving torque of the hub motor of the electric automobile under the driving working condition;

and the fourth control module is used for distributing and controlling the braking torque of the hub motor of the electric automobile under the braking working condition.

Optionally, under the driving condition, the first control module 904 is specifically configured to:

when the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to a left front wheel so that the first slip ratio is equal to the second slip ratio;

when the first slip ratio is smaller than the second slip ratio, controlling the hydraulic braking force applied to the right front wheel so that the first slip ratio is equal to the second slip ratio;

when the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

when the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

when the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, controlling the hydraulic braking force applied to the two front wheels so that the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio are equal when the first slip ratio is greater than the third slip ratio; and when the first slip ratio is smaller than the third slip ratio, applying hydraulic braking force to the two rear wheels to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

Optionally, under the braking condition or the coasting condition, the first control module 904 is specifically configured to:

when the first slip ratio is larger than the second slip ratio, controlling to apply hydraulic braking force to the right front wheel so that the first slip ratio is equal to the second slip ratio;

when the first slip ratio is smaller than the second slip ratio, controlling to apply hydraulic braking force to a left front wheel so that the first slip ratio is equal to the second slip ratio;

when the third slip ratio is larger than the fourth slip ratio, controlling to apply hydraulic braking force to the right rear wheel so that the third slip ratio is equal to the fourth slip ratio;

when the third slip ratio is smaller than the fourth slip ratio, controlling to apply hydraulic braking force to the left rear wheel so that the third slip ratio is equal to the fourth slip ratio;

when the first slip ratio is equal to the second slip ratio and the third slip ratio is equal to the fourth slip ratio, controlling the application of hydraulic braking force to the two rear wheels so that the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio are equal when the first slip ratio is greater than the third slip ratio; and when the first slip ratio is smaller than the third slip ratio, controlling the hydraulic braking force applied to the two front wheels so as to enable the first slip ratio, the second slip ratio, the third slip ratio and the fourth slip ratio to be equal.

The apparatus is an apparatus corresponding to the method embodiments of fig. 3 to 8, and all the implementation manners in the method embodiments are applicable to the embodiment of the apparatus, and the same technical effects as the method embodiments can be achieved.

Further, the present invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the control method of the distributed drive type electric vehicle as described above.

According to the scheme, by adding the control strategies of mode identification and stability mode selection of tire pressure monitoring, the relation between hydraulic braking and motor driving energy can be further coordinated, when the tire pressure changes violently, the stability of the automobile can be controlled, the safe and effective reduction of the automobile speed is realized, and the system safety in the driving process is improved.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically connected, electrically connected or can communicate with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.