CN110884356B - Energy recovery device for automatic driving vehicle - Google Patents
Energy recovery device for automatic driving vehicle Download PDFInfo
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- CN110884356B CN110884356B CN201911144594.2A CN201911144594A CN110884356B CN 110884356 B CN110884356 B CN 110884356B CN 201911144594 A CN201911144594 A CN 201911144594A CN 110884356 B CN110884356 B CN 110884356B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L7/00—Electrodynamic brake systems for vehicles in general
- B60L7/10—Dynamic electric regenerative braking
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L7/00—Electrodynamic brake systems for vehicles in general
- B60L7/10—Dynamic electric regenerative braking
- B60L7/18—Controlling the braking effect
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Abstract
The invention discloses an energy recovery device of an automatic driving vehicle, which comprises an external input system and a braking system, wherein the external input system is connected with the braking system; the external input system is used for detecting a distance to be braked, and comprises a critical safe braking distance and an economic braking distance; the braking system comprises a mechanical braking system and a hydraulic regenerative braking system; the vehicle control system controls the brake system to brake the vehicle according to the distance to be braked, and comprises a first brake state and a second brake state; in the first braking state, only a hydraulic regenerative braking system is adopted for braking; in a second braking state, only a mechanical braking system is adopted for braking; the invention can realize the braking of the braking system to the vehicle without artificial control, and can directly switch the hydraulic regenerative braking system and the mechanical braking system by the vehicle control system through the economic braking distance and the critical safe braking distance, thereby realizing partial energy recovery and improving the energy utilization efficiency.
Description
Technical Field
The invention belongs to the field of brake systems, and particularly relates to an energy recovery device of an automatic driving vehicle.
Background
As seen in the prior art, the existing vehicle generally implements the running of the vehicle based on the specific operation of the driver, for example, when the vehicle brakes, the hydraulic regeneration system may determine the stepping depth of the brake pedal through the control system based on the input of the driver to the brake pedal, and invoke different strategies to implement the energy recovery operation.
However, with the development of the automatic driving technology, the automatic driving level is continuously improved, even when the automatic driving level reaches the level of L4/L5, the vehicle abandons the brake pedal, the VCU directly controls the mechanical brake system to brake through the CAN bus during braking, and the hydraulic regenerative system cannot execute the brake energy recovery operation based on the input of the brake pedal because the hydraulic regenerative system does not have the input of the brake pedal.
Disclosure of Invention
The invention aims to provide an energy recovery device of an automatic driving vehicle, which aims to solve the problems that the automatic driving vehicle cannot brake the vehicle based on a brake pedal and cannot perform energy recovery operation in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
an energy recovery device for an autonomous vehicle, comprising
An external input system for detecting a braking distance d including a critical safety braking distance dminAnd an economic braking distance deco；
The braking system comprises a mechanical braking system and a hydraulic regenerative braking system;
vehicle control system according to standbyThe moving distance d controls the brake system to brake the vehicle, and the moving distance d comprises a first brake state and a second brake state; in a first braking state, dmin＜d≤decoOnly a hydraulic regenerative braking system is adopted for braking; d is less than or equal to d in the second braking stateminAnd only a mechanical braking system is adopted for braking.
Preferably, the hydraulic regenerative braking system comprises a hydraulic pump/motor, a hydraulic accumulator and a hydraulic control unit; the hydraulic pump/motor is connected with the hydraulic accumulator; when a vehicle is started, a hydraulic control unit receives a signal of a vehicle control system and controls a hydraulic pump/motor to work under a motor working condition, a hydraulic accumulator provides a high-pressure oil source for the hydraulic pump/motor, and the hydraulic pump/motor converts hydraulic energy into mechanical energy; when the hydraulic regenerative braking system is used for braking a vehicle, the hydraulic control unit receives signals of the vehicle control system and controls the hydraulic pump/motor to work under a pump working condition, the hydraulic pump/motor converts mechanical energy into hydraulic energy, and the hydraulic energy is stored in the hydraulic accumulator.
Preferably, the energy recovery device further comprises a battery management system; the battery management system is connected with the motor control system and supplies power to the motor control system; the motor control system is connected with the transmission system and used as a power source of the transmission system; the transmission system is connected with the vehicle and is used for driving the vehicle to move; the vehicle control system is respectively connected with an external input system, a mechanical braking system, a hydraulic regenerative braking system, a battery management system, a motor control system and a transmission system through a CAN bus.
Preferably, the transmission system comprises a clutch, a transmission and a torque coupler, wherein a motor in the motor control system is connected with the transmission through the clutch, and the clutch is controlled by a vehicle control system; the transmission and hydraulic pump/motor are connected to torque couplers, respectively, which are connected to the wheels through drive shafts.
Preferably, the economic braking distance decoWhen a vehicle control system detects that the vehicle control system has collision danger with an obstacle, hydraulic regenerative braking is immediately adopted for braking, and the distance between the vehicle and the obstacle is kept; critical point of the aboveSafety braking distance dminThe vehicle control system immediately adopts a mechanical braking system to brake when detecting that the vehicle control system has collision danger with an obstacle, and the distance between the vehicle and the obstacle is at the moment.
Preferably, the economic braking distance and the critical safety braking distance each comprise a minimum safety distance d0(ii) a The expression of the economic braking distance is recorded according to the motion state of the obstacle
Wherein v is1Is the speed of movement of the obstacle, v2Is the running speed of the own vehicle, t2For the reaction time of a hydraulic regenerative braking system, aregIs the maximum braking deceleration that the hydraulic regenerative braking system can provide, af_maxThe maximum braking deceleration when the obstacle is emergently braked; the expression of the critical safety braking distance is recorded according to the motion state of the obstacle
Wherein, t1Response time for mechanical braking systems, amaxIs the maximum braking deceleration that the mechanical braking system can provide, af_maxThe maximum braking deceleration when the obstacle brakes suddenly.
Preferably, the maximum braking deceleration a that the hydraulic regenerative braking system can provideregIs calculated as follows:
Treg＝Tpumpi0i1，
wherein, TregMaximum braking torque transferred to the wheels for the hydraulic regenerative system, r is the rolling radius of the wheels, mcarIs the weight of the vehicle, TpumpMaximum torque generated by the hydraulic pump/motor when the vehicle is braking or driving, i0To the transmission ratio of the variator, i1For torque couplingThe transmission ratio of the device, p is the pressure at the oil outlet of the hydraulic pump/motor, etamQ is the displacement of the hydraulic pump/motor for its mechanical efficiency.
Preferably, the external input system comprises an environment sensing system and a positioning navigation system, the environment sensing system comprises a plurality of sensors, and the sensors acquire and process data to obtain motion parameters of surrounding obstacles, including a distance to be braked; the positioning navigation system positions the vehicle in real time through the positioning navigation component to determine the driving route.
Preferably, the environment sensing system comprises a plurality of binocular cameras, a plurality of long-wave laser radars and a plurality of millimeter-wave radars;
the positioning and navigation component comprises
GPS, position the vehicle;
the inertial navigation system corrects the positioning of the GPS to the vehicle and detects the running state of the vehicle;
the high-precision map provides static and dynamic traffic information and is combined with the current position of the vehicle to plan a path.
Preferably, the energy recovery device is for an L4 or L5 class vehicle.
Compared with the prior art, the invention has the beneficial effects that:
the braking of the vehicle by the braking system can be realized without artificial control, and the hydraulic regenerative braking system and the mechanical braking system can be directly switched by the vehicle control system through the economic braking distance and the critical safe braking distance, so that partial energy recovery is realized; the power system and the hydraulic regenerative braking system are connected through the torque coupler, so that the torque is increased, and the energy waste is reduced.
Drawings
Fig. 1 is a schematic diagram of the present invention.
FIG. 2 is a schematic view of the structure of the present invention.
Fig. 3 is a diagram of the movement locus of the vehicle and the obstacle.
Reference numerals: 1-external input system, 2-hydraulic regenerative braking system, 3-mechanical braking system, 4-motor control system, 5-battery management system, 6-transmission system, 7-driving shaft, 8-wheel, 21-hydraulic regenerative control unit, 22-high pressure accumulator, 23-low pressure accumulator, 24-hydraulic pump/motor, 41-motor controller, 42-motor, 51-battery controller, 52-battery, 61-transmission, 62-torque coupler.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
An energy recovery device for an autonomous vehicle, the vehicle braking system comprising
An external input system for detecting a braking distance d including a critical safety braking distance dminAnd an economic braking distance deco；
The braking system comprises a mechanical braking system and a hydraulic regenerative braking system;
the vehicle control system controls the brake system to brake the vehicle according to the distance d to be braked, and comprises a first brake state and a second brake state; in a first braking state, dmin＜d≤decoOnly a hydraulic regenerative braking system is adopted for braking; d is less than or equal to d in the second braking stateminAnd only a mechanical braking system is adopted for braking.
In the invention, the mechanical brake system can be a drive-by-wire hydraulic brake system of a vehicle, and is a conventional brake system composed of a brake disc, a caliper and the like, which is common knowledge of ordinary technicians in the field and can be set by the technicians in the field according to actual conditions.
The economic braking distance decoWhen a vehicle control system detects that the vehicle control system has collision danger with an obstacle, hydraulic regenerative braking is immediately adopted for braking, and the distance between the vehicle and the obstacle is kept; the critical safety braking distance dminIs a vehicleWhen the vehicle control system detects that the vehicle is in collision danger with the obstacle, the vehicle control system immediately adopts the mechanical braking system to brake, and the distance between the vehicle and the obstacle is kept at the moment.
In the invention, the obstacles comprise front vehicles, stones, traffic police and other people and objects which prevent the vehicles from moving.
In the invention, when the mechanical brake system is used for braking, the mechanical brake system converts mechanical energy into heat energy and finally wastes the heat energy in the form of heat, and when the hydraulic regenerative brake system is used for braking, the hydraulic regenerative brake system converts the mechanical energy into hydraulic energy for storage, thereby realizing the recovery of partial kinetic energy and improving the utilization efficiency of energy.
According to the invention, when the vehicle control system detects that the distance to be braked is greater than the economic braking distance according to the external input system, the vehicle and the front obstacle are not in collision risk, so that the vehicle is not braked; in order to improve the energy utilization efficiency as much as possible, a hydraulic regenerative braking system is firstly adopted to brake the vehicle with medium and small braking intensity (the braking deceleration is less than or equal to 0.4g) during braking, so that the economic braking distance is greater than the critical safe braking distance; when the vehicle control system detects that the distance to be braked is equal to or equal to the economic braking distance according to the external input system, the hydraulic regenerative braking system is immediately adopted to continuously brake the vehicle, in the process, the mechanical braking system does not participate in work, the hydraulic regenerative braking system continuously recovers energy until the distance between the vehicle and the front vehicle reaches the critical safety distance, if the hydraulic regenerative braking system is still adopted to recover the braking energy, the risk that the vehicle and the obstacle collide cannot be ensured, therefore, when the distance between the vehicle and the obstacle, namely the distance to be braked is smaller than or equal to the critical safety braking distance, the mechanical braking system is adopted to perform emergency braking, and energy recovery is not performed.
In the invention, an external input system detects a distance to be braked and transmits the distance to a vehicle control system, and the vehicle control system distributes braking force to a mechanical braking system and a hydraulic regenerative braking system by judging the relation between the distance to be braked and an economic braking distance and a critical safe braking distance; the invention directly determines the braking state through the vehicle control system without artificial determination, thereby realizing the intellectualization of vehicle braking.
The economic braking distance and the critical safety distance respectively comprise a minimum safety distance d0。
In the present invention, the minimum safety distance d0The distance between the vehicle and the obstacle when the obstacle stops or the moving speed of the vehicle and the obstacle is the same is set to reduce the risk of collision between the vehicle and the obstacle by setting the minimum safe distance, the value of the minimum safe distance is a conventional technical means in the field, and the minimum safe distance can be set by a person skilled in the art according to the actual situation.
The economic braking distance decoThe different movement states according to the obstacles are recorded as
v1Is the speed of movement of the obstacle, v2Is the running speed of the own vehicle, t1For the reaction time of a hydraulic regenerative braking system, aregIs the maximum braking deceleration that the hydraulic regenerative system can provide, af_maxThe maximum braking deceleration when the obstacle is emergently braked;
critical safety braking distance dminThe different movement states according to the obstacles are recorded as
Wherein v is1Is the speed of movement of the obstacle, v2Is the running speed of the own vehicle, t2Reaction time of the mechanical braking system; a ismaxIs the maximum braking deceleration that the mechanical braking system can provide, af_maxThe maximum braking deceleration when the obstacle brakes suddenly.
In the present invention, regardless of the hydraulic regenerative braking system or the mechanical braking system, the braking of the vehicle requires a reaction time, t1、t2。
In the invention, the running speed of the vehicle can be obtained by a speed sensor arranged in the vehicle or calculated based on parameters obtained by various sensors in an external input system, which is a conventional technical means in the field, and can be set by a person skilled in the art according to the actual situation; the movement speed of the obstacle and the maximum braking deceleration during emergency braking can be calculated based on parameters obtained by various sensors and positioning navigation components in an external input system, and the method also belongs to conventional technical means in the field, and can be set by a person skilled in the art according to the actual situation.
In the present invention, as shown in FIG. 3, the economic braking distance decoThe expression (d) is a distance d over which the own vehicle B travels from the start to the end of braking by using a hydraulic regenerative braking system2Moving distance d from the obstacle A1Difference plus minimum safety distance d0Is denoted by deco＝d2-d1+d0Critical safety braking distance dminIs the distance d traveled by the vehicle from the beginning to the end of braking with a mechanical braking system2Distance d from obstacle1Difference plus minimum safety distance d0Is denoted by dmin＝d2-d1+d0。
The difference between the vehicle running distance and the barrier movement distance is calculated in different manners due to different movement states of the barriers, and finally the expression of the economic braking distance or the critical safety braking distance is divided into three expressions according to the movement state of the barriers, wherein the economic braking safety distance decoThe expression of (A) is divided into:
(1) when the vehicle drives at v1When the moving speed of the hydraulic regenerative braking system detects that the front barrier is static, the reaction time t of the hydraulic regenerative braking system is passed1Then at deceleration aregDeceleration to vehicle stop, time taken
Meanwhile, in order to avoid collision, the distance between the rear vehicle and the obstacle should satisfy the minimum safe distance d0(ii) a Thus, it is possible to provide
(2) When the vehicle drives at v1When the moving speed of the robot moves, the robot detects that the front barrier moves at a constant speed, and the moving speed is v2Hydraulic regenerative braking system over reaction time t1Then at deceleration aregDecelerating to velocity v2Time taken
At the same time, the distance to avoid collision with an obstacle should satisfy the minimum safety distance d0(ii) a Thus, it is possible to provide
(3) When the vehicle drives at v1When the moving speed of the front obstacle is detected to be v2Maximum braking deceleration af_maxEmergency braking is carried out until the vehicle stops, and in order to avoid collision, the distance between the stopped vehicle and the obstacle should meet the minimum safe distance d0(ii) a Thus, it is possible to provide
Since the detected speed is calculated in km/h and the relevant time in the expression is calculated in units of s, the relevant speed needs to be converted into m/s for calculation, and 3.6km/h is 1 m/s.
Maximum brake deceleration a that can be provided by a hydraulic regenerative braking systemregIs calculated as follows:
Treg＝Tpumpi0i1，
In the invention, the rated parameters are set by the technicians in the field according to requirements.
The external input system comprises an environment sensing system and a positioning navigation system, the environment sensing system comprises a plurality of sensors, and the sensors acquire and process data to obtain motion parameters of surrounding obstacles, including a distance to be braked; the positioning navigation system positions the vehicle in real time through the positioning navigation component to determine the driving route.
The environment sensing system comprises a plurality of binocular cameras, a plurality of long-wave laser radars and a plurality of millimeter-wave radars;
in the invention, a binocular camera is used, the detection range is 50 degrees/150 m, the binocular camera is arranged on the front glass of the automobile and is used for capturing image data comprising obstacle information, lane information (lane attribute, offset, road curvature and the like) and traffic signal information (traffic sign, traffic light and the like); the long-wave laser radar is arranged on the roof, is mainly used for detecting road edges and front obstacles and acquiring target information in the running environment of the vehicle, wherein the target information comprises longitude and latitude of the obstacles, actual distance between the vehicle and the front obstacles, namely the distance to be braked and the like; four short-wave millimeter wave radars with a detection range of 110 degrees/60 m are used for detecting obstacles on two sides of a running vehicle and the distance between the obstacles;
the positioning navigation component comprises a GPS, an inertial navigation system and a high-precision map,
GPS, position the vehicle;
the inertial navigation system corrects the positioning of the GPS to the vehicle and detects the running state of the vehicle;
the high-precision map provides static and dynamic traffic information and is combined with the current position of the vehicle to plan a path.
In the positioning navigation system, a GPS is arranged in the middle of the roof of a vehicle and is used for positioning the vehicle; the inertial navigation system finally ensures the accurate position of the vehicle in a map by continuously correcting the GPS positioning, and can detect the states of the vehicle such as speed, roll angle, yaw angle and the like during running; the high-precision map provides static and dynamic traffic information for vehicle navigation and path planning from the current position to the target position.
The hydraulic regenerative braking system includes a hydraulic pump/motor, a hydraulic accumulator, and a hydraulic control unit; the hydraulic pump/motor is connected with the hydraulic accumulator; when a vehicle is started, a hydraulic control unit receives a signal of a vehicle control system and controls a hydraulic pump/motor to work under a motor working condition, a hydraulic accumulator provides a high-pressure oil source for the hydraulic pump/motor, and the hydraulic pump/motor converts hydraulic energy into mechanical energy; when the hydraulic regenerative braking system is used for braking a vehicle, the hydraulic control unit receives signals of the vehicle control system and controls the hydraulic pump/motor to work under a pump working condition, the hydraulic pump/motor converts mechanical energy into hydraulic energy, and the hydraulic energy is stored in the hydraulic accumulator.
In the invention, the hydraulic pump/motor is a reversible element and has both the pump working condition and the motor working condition, and the hydraulic pump/motor is a swash plate type plunger variable pump (model A4VSO125) of German Leishile; the hydraulic energy accumulator comprises a high-pressure energy accumulator and a low-pressure energy accumulator, the high-pressure energy accumulator is connected with an oil inlet of the hydraulic pump/motor, and the low-pressure energy accumulator is connected with an oil outlet of the hydraulic pump/motor; electromagnetic valves are respectively arranged between the high-pressure energy accumulator and the hydraulic pump/motor and between the low-pressure energy accumulator and the hydraulic pump/motor, the electromagnetic valves are controlled by a hydraulic control unit, and the electromagnetic valves are two-position two-way electromagnetic reversing valves; an oil inlet of the two-position two-way reversing valve is connected with the high-pressure energy accumulator, and an oil outlet of the two-position two-way reversing valve is connected with an oil inlet of the hydraulic pump/motor; an oil inlet of the other two-position two-way reversing valve is connected with an oil outlet of the hydraulic pump/motor, and an oil outlet of the other two-position two-way reversing valve is connected with the low-pressure energy accumulator; when the hydraulic pump/motor does not work, the electromagnetic valve is not electrified, and the oil does not flow; when the hydraulic control unit controls the hydraulic pump/motor to be in a motor working condition, the hydraulic control unit simultaneously controls the electromagnetic valve to be electrified, the valve core of the electromagnetic valve is opened, and oil of the high-pressure energy accumulator flows to the low-pressure energy accumulator through the hydraulic pump/motor to provide a high-pressure oil source for the hydraulic pump/motor; when the hydraulic control unit controls the hydraulic pump/motor to be in a pump working condition, the hydraulic control unit simultaneously controls the valve core of the electromagnetic valve to be opened, and the hydraulic pump/motor sucks oil in the low-pressure accumulator to form pressure oil which is discharged into the high-pressure accumulator.
The energy recovery device further comprises a battery management system; the battery management system is connected with the motor control system and supplies power to the motor control system; the motor control system is connected with the transmission system and used as a power source of the transmission system; the transmission system is connected with the vehicle and is used for driving the vehicle to move; the vehicle control system is respectively connected with an external input system, a mechanical braking system, a hydraulic regenerative braking system, a battery management system, a motor control system and a transmission system through a CAN bus.
The transmission system comprises a clutch, a transmission and a torque coupler, wherein a motor in the motor control system is connected with the transmission through the clutch, and the clutch is controlled by a vehicle control system; the transmission and hydraulic pump/motor are connected to torque couplers, respectively, which are connected to the wheels through drive shafts.
In the invention, a rotating shaft of a clutch control motor is connected with a rotating shaft at one end of a transmission, the clutch is controlled by a vehicle control system, when the vehicle is started, the clutch is closed and linked, the rotating shaft of the motor is linked with the rotating shaft at one end of the transmission, the rotating shaft at the other end of the transmission is connected with the input end of a torque coupler, a power output shaft of a hydraulic pump/motor is connected with the input end of the torque coupler through the clutch, the output end of the torque coupler is connected with a driving shaft, and two ends of the driving shaft are connected with wheels; the specific connection relationship of the above components is common knowledge of those skilled in the art, and those skilled in the art can set the connection relationship according to actual situations.
The motor control system comprises a motor controller and a motor, wherein the motor controller is electrically connected with the motor and used for controlling the working state of the motor, the motor is used as a power source of a transmission system, the battery management system comprises a storage battery controller and a storage battery, the storage battery controller is electrically connected with the storage battery, the storage battery is electrically connected with the motor, and the storage battery controller controls the storage battery to supply power to the motor and monitor the electric quantity of the storage battery; the vehicle control system is respectively connected with each controller and each sensor, so that real-time communication between the vehicle control system and each system is realized, and external environment parameters and vehicle parameters are obtained and continuously updated.
When the vehicle is driven, the vehicle control system sends an instruction to the storage battery controller through the CAN bus, the storage battery controller controls the storage battery to discharge electricity to provide electric energy for the motor, meanwhile, the vehicle control system sends an instruction to the motor controller, and the motor controller controls the motor to work to convert the electric energy of the storage battery into kinetic energy through the motor; meanwhile, the hydraulic control unit receives an instruction sent by a vehicle control system, the electromagnetic valve is controlled to be electrified, oil liquid of the high-pressure energy accumulator flows to the low-pressure energy accumulator through the electromagnetic valve to provide a high-pressure oil source for the hydraulic pump/motor, the hydraulic pump/motor works in a motor mode and positively rotates to generate driving torque to be transmitted to the torque coupler, the torque coupler is responsible for coupling the torque generated by the hydraulic pump/motor in the hydraulic regeneration system through the torque and the torque generated by the transmission in the transmission system, the two systems can simultaneously work when starting and accelerating, the driving torque is provided for the driving shaft to be transmitted to the driving wheel, and the driving shaft drives the wheels to rotate;
when the vehicle needs to be in a first braking state, the vehicle control system controls a clutch in a transmission system to be disconnected, at the moment, the battery management system does not transmit energy to the motor control system, the vehicle control system sends an instruction to the battery controller and the motor controller through the CAN bus to respectively control the battery to stop supplying power and control the motor to stop working, the hydraulic control unit receives a braking instruction sent by the vehicle control system, controls the hydraulic pump/motor to continuously reverse under the inertia force of wheels, controls the electromagnetic valve to be electrified, oil liquid of the low-pressure energy accumulator flows to the high-pressure energy accumulator through the electromagnetic valve and the hydraulic pump/motor, stores kinetic energy of the vehicle in a hydraulic energy mode, and at the moment, the hydraulic pump/motor works in a hydraulic pump mode;
when the vehicle is in the second braking state; the vehicle control system controls the disconnection of the clutch between the torque coupling and the hydraulic pump/motor, and at the same time controls the mechanical braking system to perform mechanical braking, at which time no energy recovery is performed.
The low-voltage electrical appliances such as the motor controller, the storage battery controller, the sensor and the like are powered by other storage batteries.
The energy recovery device is used for an L4 or L5 grade automobile.
Claims (7)
1. An energy recovery device for an autonomous vehicle, comprising
An external input system for detecting a braking distance d including a critical safety braking distance dminAnd an economic braking distance deco；
The braking system comprises a mechanical braking system and a hydraulic regenerative braking system;
the vehicle control system controls the brake system to brake the vehicle according to the distance d to be braked, and comprises a first brake state and a second brake state; in a first braking state, dmin＜d≤decoOnly a hydraulic regenerative braking system is adopted for braking; d is less than or equal to d in the second braking stateminOnly a mechanical braking system is adopted for braking;
the economic braking distance decoWhen a vehicle control system detects that the vehicle control system has collision danger with an obstacle, hydraulic regenerative braking is immediately adopted for braking, and the distance between the vehicle and the obstacle is kept; the critical safety braking distance dminWhen a vehicle control system detects that the vehicle control system has collision danger with an obstacle, a mechanical braking system is immediately adopted for braking, and the distance between the vehicle and the obstacle is kept;
the economic braking distance and the critical safety braking distance both comprise a minimum safety distance d0；
The expression of the economic braking distance is recorded according to the motion state of the obstacle
Wherein v is1Is the speed of movement of the obstacle, v2Is the running speed of the own vehicle, t2For the reaction time of a hydraulic regenerative braking system, aregIs the maximum braking deceleration that the hydraulic regenerative braking system can provide, af_maxThe maximum braking deceleration when the obstacle is emergently braked; the expression of the critical safety braking distance is recorded according to the motion state of the obstacle
Wherein, t1Response time for mechanical braking systems, amaxIs the maximum braking deceleration that the mechanical braking system can provide, af_maxThe maximum braking deceleration when the obstacle is emergently braked;
the hydraulic regenerative braking system includes a hydraulic pump/motor, a hydraulic accumulator, and a hydraulic control unit; the hydraulic pump/motor is connected with the hydraulic accumulator; when the vehicle is started, the hydraulic control unit receives a signal of a vehicle control system and controls the hydraulic pump/motor to work under the working condition of the motor, the hydraulic accumulator provides a high-pressure oil source for the hydraulic pump/motor, and the hydraulic pump/motor converts hydraulic energy into mechanical energy; when the hydraulic regenerative braking system is used for braking a vehicle, the hydraulic control unit receives signals of the vehicle control system and controls the hydraulic pump/motor to work under a pump working condition, the hydraulic pump/motor converts mechanical energy into hydraulic energy, and the hydraulic energy is stored in the hydraulic accumulator.
2. The energy recovery device of an autonomous vehicle as recited in claim 1, wherein said energy recovery device further comprises a battery management system; the battery management system is connected with the motor control system and supplies power to the motor control system; the motor control system is connected with the transmission system and used as a power source of the transmission system; the transmission system is connected with the vehicle and is used for driving the vehicle to move; the vehicle control system is respectively connected with an external input system, a mechanical braking system, a hydraulic regenerative braking system, a battery management system, a motor control system and a transmission system through a CAN bus.
3. The energy recovery device of an autonomous vehicle as claimed in claim 2, wherein the transmission system comprises a clutch, a transmission, a torque coupling, the electric machine of the electric machine control system is connected with the transmission through the clutch, and the clutch is controlled by the vehicle control system; the transmission and hydraulic pump/motor are connected to torque couplers, respectively, which are connected to the wheels through drive shafts.
4. An energy recovery device for an autonomous vehicle as claimed in claim 1, characterized in that the maximum braking deceleration a that the hydraulic regenerative braking system can provideregIs calculated as follows:
Treg＝Tpumpi0i1，
wherein, TregMaximum braking torque transferred to the wheels for the hydraulic regenerative system, r is the rolling radius of the wheels, mcarIs the weight of the vehicle, TpumpMaximum torque generated by the hydraulic pump/motor when the vehicle is braking or driving, i0To the transmission ratio of the variator, i1For torque coupler ratio, p is the pressure at the hydraulic pump/motor outlet, ηmQ is the displacement of the hydraulic pump/motor for its mechanical efficiency.
5. The energy recovery device of an autonomous vehicle as claimed in claim 1, wherein the external input system comprises an environment sensing system and a positioning navigation system, the environment sensing system comprises a plurality of sensors, the sensors collect data and process the data to obtain the motion parameters of surrounding obstacles, including the distance to be braked; the positioning navigation system positions the vehicle in real time through the positioning navigation component to determine the driving route.
6. The energy recovery device of an autonomous vehicle as claimed in claim 5, wherein the environment sensing system comprises a plurality of binocular cameras, a plurality of long-wave lidar, a plurality of millimeter-wave radar;
the positioning and navigation component comprises
GPS, position the vehicle;
the inertial navigation system corrects the positioning of the GPS to the vehicle and detects the running state of the vehicle; the high-precision map provides static and dynamic traffic information and is combined with the current position of the vehicle to plan a path.
7. An energy recovery device for an autonomous vehicle as claimed in claim 1, characterized in that the energy recovery device is for a class L4 or L5 car.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911144594.2A CN110884356B (en) | 2019-11-20 | 2019-11-20 | Energy recovery device for automatic driving vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911144594.2A CN110884356B (en) | 2019-11-20 | 2019-11-20 | Energy recovery device for automatic driving vehicle |
Publications (2)
| Publication Number | Publication Date |
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| CN110884356A CN110884356A (en) | 2020-03-17 |
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