Analysis of Power Execution Strategy of New Energy Vehicles in ADAS System

This paper will make a detailed analysis on the power execution strategy of new energy vehicles in ADAS system, including the re formulation of power and braking distribution scheme, the change of power execution strategy and the change of braking execution strategy. In the new energy vehicle response strategy, it is divided into two different strategy vehicles. One is pure electric EV, whose central unit is controlled by VCU (vehicle control unit). The other is hybrid PHEV, whose central unit is controlled by PCU (power control unit). This paper will focus on the analysis of pure electric VCU control logic, as shown in the following figure, which shows the corresponding network topology of EV.

1) Transmission unit TCU is no longer used as a separate ECU to control shift and torque response logic in new energy vehicles, but only as an input port to receive driver gear types (P, R, N, d);

2) MCU is a unique core power electronic unit of energy vehicles. After being connected with VCU through newpowercan line, MCU receives the vehicle driving control command signal from VCU, controls the motor to output the specified torque and speed, and drives the vehicle. The DC of the power battery is converted into high-voltage AC, and the parallel drive motor body outputs mechanical energy.

3) Battery management system (BMS) is mainly used to intelligently manage and maintain each battery unit, prevent overcharge and over discharge of the battery, prolong the service life of the battery and monitor the state of the battery.

4) After the driver turns on the cruise setting switch of the ADAS system, connect the VCU through the hard wire. After analyzing the driver's input setting through the VCU, respond to its corresponding cruise control logic of the ADAS system.

5) VCU is directly connected to the braking system epbi through ptcan, and is also connected to the ADAS system through newpowercan and gateway to send the electric braking torque limit to the braking system, receive the braking system and ADAS torque request, and then send the execution torque result to the braking system epbi and ADAS system;

6) After the body controller BCM is connected to the gateway GW through bcan, it sends the vehicle information to ADAS system and other can lines. At the same time, the instrument IP receives the prompt and alarm information sent by each controller and displays it on the instrument panel to remind and alarm the driver;

7) The driving assistance system ADAS is connected to the gateway through adascan and controls the acceleration and deceleration of the vehicle after transmitting data to new powercan and ptcan;

one

Control strategy design of ADAS and VCU

In the driving assistance strategy of pure electric EV, there are two different power output distribution logic, mainly for different strategies of vehicle longitudinal control (VLC), which are expressed as follows:

1. VLC control by ADAS system:

Principle:

Under this control logic, VCU only responds to ADAS acceleration control command, and epbi is responsible for ADAS deceleration control command;

Adas system judges the current actual state through the detection of environmental information and vehicle information (including obtaining driver input settings, vehicle speed acquisition and vehicle attitude), and sends forward torque to VCU when there is acceleration demand. VCU needs to receive the torque value sent by ADAS controller_ Torque (0 100%) and torque effective status Adas_ Calculate and generate virtual accelerator pedal opening VCU after torqueactive = active_ The virtual throttle position is used to input the pedal opening into the powertrain control logic to generate driving demand and powertrain response kinetic energy, so as to formulate reasonable power output and energy recovery strategies.

When a deceleration control request is required, the epbi system performs deceleration response control. Its control mode is still in accordance with the traditional ADAS deceleration control strategy. First, the ADAS system sends a torque reduction request to the VCU to perform anti drag control. When the ADAS determines that the anti drag capacity of the VCU is insufficient by detecting acceleration, speed and relative distance, the ADAS system sends a deceleration command to the epbi, Then epbi generates the corresponding braking force according to the deceleration value in response to the request of ADAS system.

As shown in the figure above, the data flow diagram of the three modules of new energy vehicle in the control VLC logic of ADAS system is shown in detail. The working process is described in detail below:

1) The "braking electric night distribution module" of ADAS system first receives the "electric system torque limit value" sent by VCU and the "hydraulic torque limit value" sent by epbi, and sends "driving electric torque" and "braking electric torque" to the "torque target analysis module" of VCU respectively according to the actual situation of the detected environment, and sends "hydraulic execution torque" to the "torque hydraulic conversion module" in epbi at the same time 。

2) After receiving the electric torque request sent by ADAS, the "torque target analysis module" in VCU analyzes it into the actual torque value of the motor and outputs it to the signal verification module in epbi control module. The electro-hydraulic distribution module in epbi controls the parameter value of "torque hydraulic conversion module" according to the safety verification results.

3) The torque demand arbitration module in epbi needs to receive the sliding target torque output value and braking target torque value sent by VCU, and comprehensively output the braking target torque to the "anti drag torque arbitration module" of ADAS system.

4) The "anti drag torque arbitration" module in ADAS system receives the sliding target torque sent by VCU, the braking target torque sent by epbi and the braking target torque value sent by ADAS itself for arbitration, and outputs the corresponding torque arbitration results to the braking electro-hydraulic distribution of ADAS system.

Adas system is responsible for driving target analysis and anti drag target arbitration on the environmental detected data to generate corresponding acceleration torque and anti drag torque. When it is necessary to cut in braking, analyze the braking target to generate corresponding braking deceleration. In this process, epbi and ADAS need to adopt the principle of unity and give priority to the distribution of electric braking. At the same time, epbi and ADAS controllers need to The self torque is sent out for the other two controllers to make a smooth torque transition.

Summary:

In this method, epbi is responsible for electro-hydraulic distribution and safety control under driving conditions, and ADAS system is responsible for front-end electro-hydraulic distribution and safety control. This control mode has the following advantages:

Compared with the braking system epbi, ADAS can use sensor devices (such as front radar, camera, etc.) to detect environmental information. It has great prediction ability, including in full speed adaptive cruise, which is more convenient to complete the electro-hydraulic transition during parking and starting transition under normal driving conditions. On the premise of fully ensuring safety, ADAS can provide greater energy recovery.

Of course, the control mode also includes the following disadvantages:

When ACC enters the braking deceleration condition from the driving acceleration condition, considering the smoothness of switching between working conditions, ACC and ESP controllers shall conduct torque demand arbitration with certain repeatability. It can be seen from the figure that under this control mode, there are many signal interaction interfaces between controllers, including signal verification, large amount of clock synchronization data and relatively complex algorithm.

2. VLC control by braking system epbi system:

Principle:

Under this logic, after receiving the ADAS acceleration command, the epbi system converts the acceleration torque value executed by the VCU and sends it to the VCU. After receiving the forward acceleration torque request epbi_torque and the effective status bit epbi_torque sent by the epbi, the VCU generates a virtual accelerator pedal opening vcu_virtualthrottleposition, which is used to input into the powertrain control logic to generate driving demand and powertrain Response to kinetic energy, and then formulate reasonable power output and energy recovery strategies.

At this time, if ADAS has no acceleration request or the acceleration request torque is less than the idle torque, the power torque request will not be distributed.

After receiving the deceleration command sent by ADAS, epbi system converts the deceleration and torque reduction request command epbi_torque to be executed by VCU and first sends it to VCU to execute corresponding torque reduction and reverse drag deceleration. At this time, epbi needs to receive the execution status of the whole vehicle (including speed V and deceleration a), judge to stop sending torque reduction request at an appropriate time, and control its own pressure to generate braking deceleration.

As shown in the figure above, the data flow diagram of three modules of new energy vehicle in epbi system control VLC logic is shown in detail. The working process is described in detail below:

1) "Drive target resolution" in ADAS system during acceleration The module sends the drive acceleration value to the ESP torque demand arbitration module. After passing the security check mechanism, the module outputs the torque value to the torque target analysis module in VCU, and then generates the actual motor executable torque after analyzing the torque. The torque is input to the safety check module of the braking system EPBi at the same time, and the EPBi electro-hydraulic distribution module receives the safety check signal to adjust the actual value. The hydraulic execution torque value outputs the corresponding hydraulic pressure value to the electro-hydraulic distribution module through the "torque to hydraulic pressure" module.

2) "Braking target analysis" in ADAS system during deceleration The module sends the corresponding deceleration value to the ESP torque demand arbitration module. After receiving the sliding torque and braking target analytical value sent by VCU at the same time, the module outputs the corresponding original analytical torque value to the electro-hydraulic distribution module. The module generates the hydraulic execution torque and outputs it to the torque to hydraulic pressure module, and finally generates the target hydraulic pressure.

3) In the above process, the hydraulic pressure limiting module feeds back the hydraulic execution capacity to the electro-hydraulic distribution module. At the same time, the electric system capacity limiting module in VCU also sends the electric system recovery capacity to the ESP electro-hydraulic distribution module. After the electro-hydraulic torque is calculated and verified, the module outputs the executable electric recovery torque and sends it to the VCU torque target analysis module.

Summary:

In this method, epbi is uniformly responsible for the electro-hydraulic distribution and safety control in the sliding, braking and ADAS control stages. Epbi is required to give priority to the distribution of electric braking in the control process without safety risk, and control the intervention time of hydraulic braking by monitoring the execution speed and deceleration value of the whole vehicle in real time. The above control method has the following advantages:

The functions between controllers are clearly cut and the number of interactive interfaces is small; the negative torque of the whole vehicle comes from the only controller epbi, which can realize a smooth transition between acceleration, reverse traction and braking conditions in ADAS system, and the difficulty of realizing the algorithm basically focuses on the braking system epbi. Of course, the signal interface of ADAS system needs to be changed accordingly, that is, from the original (torque FX acceleration ax) Interface, converted to pure acceleration ax interface control mode.

two

Adas and VCU response strategy under driver intervention

During the execution of the above process, VCU will monitor the driver's setting key vcu_driverset and accelerator pedal pressing state vcu_realthrottleposition at any time, ADAS system and epbi will monitor the brake pedal veh_brakepedal and other signal inputs at any time as the driver's driving intention judgment, and the following response strategies can be formulated respectively.

1) When ADAS detects that the brake pedal veh_brakepedal is pressed, it will exit the current active control, and its torque transmission valid bit adas_torqueactive will also become inactive notactive. If the current communication between ADAS system and brake system fails or there is a certain communication delay, VCU detects that the brake pedal is pressed, then the control will no longer respond to the torque sent by ADAS system Request. This control strategy can be used for double redundancy of acceleration and deceleration control.

2) When the VCU detects that the driver depresses the accelerator pedal during the acceleration control of the ADAS system, the VCU, as the core component of the power control of the EV model, needs to judge whether there is a driver surpassing the operation state of the ADAS system control with reference to the following override logic according to the real accelerator pedal position vcu_realthrottleposition and the virtual accelerator opening adas_throttle position generated by ADAS conversion.

When the ADAS system has no forward torque request (for example, when sending deceleration braking request at this time), the real driver's throttle is greater than the smaller threshold mintorq, and it is judged that

추천 기사
Dalian Pinjia Group Promotes Infineon Intelligent Vehicle Motor Drive and Motor Control Solutions
On February 18, 2016, Dalian United holdings, a leading distributor of semiconductor components committed to the Asia Pacific market, announced that its Pinjia launched an on-board intelligent motor drive and control solution based on Infineon drive chips tle986x and tle987x.With the development of automotive electronics, intelligent motor is more and more widely used in automotive electronic system, and its advantages are very obvious. At present, there are an average of 28 motors per vehicle, which is expected to rise to 30 in two years. The motor is inseparable from the drive and control device. Infineon intelligent vehicle motor driver chip has been developed to the third generation tle986x and tle987x, which can cover DC motor and DC brushless motor.Figure 1 - photo of Infineon tle987x drive and control solution development board represented by Dalian PinjiaThe series chips of Infineon launched by Dalian Pinjia this time are integrated with cortex â„¢- M3 core MCU, NMOS driver (with chargpump), PWM / Lin transceiver and 10bit ADC current sampling; Wide range of working voltage, vs = 5.4v to 28V, suitable for automotive 12V system.Figure 2 - system framework diagram of Infineon tle986x and tle987x drive and control solutions of Dalian Pinjia agencyThe main devices in the drive and control solution launched by Dalian Pinjia include tle9877qxa40, tle9867qxa40 and ipd25n06s4l-30. Its product applications are HVAC, waterpump, FUELPUMP, window lift, BLDC motor and DC motor. It can provide technical support such as specifications, development platforms, development tools, schematic diagrams, demo boards, software routines, etc.Figure 3 - photos of Infineon tle986x and tle987x drive and control solutions represented by Dalian PinjiaAbout general United Holdings:As the world's largest distributor of semiconductor components and parts with a leading market share in the Asia Pacific region, Dagu holdings is headquartered in Taipei (TSE: 3702). It has Shiping, Pinjia, Quanding and Youshang, with nearly 6000 employees, more than 250 agent product suppliers, more than 120 distribution sites around the world (about 70 in the Asia Pacific region), with a turnover of US $14.9 billion (self settled) in 2014. (* market ranking based on Gartner data)Da Lianda holdings creates an industrial holding platform, continuously optimizes the front-end marketing and logistics support team, acts as a professional partner in the industrial supply chain, and provides value-added services such as demand creation, turnkey solution, technical support, warehousing logistics and IC e-commerce to meet the needs of original equipment manufacturers (OEMs) and original design manufacturers (ODMs) , electronic manufacturing service providers (EMS) and small and medium-sized enterprises. With international business scale and localized sales channels, it has been deeply rooted in the Asia Pacific market for a long time, and has been selected as the "best IC distributor in Asia" by professional media for many years.In order to improve the localization service quality of the general assembly and meet the differentiated needs of regional customers in Greater China, the six service areas of the general assembly (China) include China based manufacturers, Taiwan based manufacturers, electronic manufacturing service, Japanese based manufacturers and Korean based manufacturers And Hong Kong based manufacturers. In addition to providing customers with the best turnkey solution, the general assembly has specially established a dedicated small batch service team (SQS) to meet customers' procurement needs of small batch devices. The general assembly has established the General Assembly commerce and trade, the General Assembly commerce and trade (Shenzhen) and the General Assembly Electronics (Hong Kong) in the mainland and Hong Kong respectively. Taking "industry first choice. Channel benchmark" as the corporate vision, the general assembly has fully implemented the core values of "team, integrity, professionalism and efficiency", and achieved mutual benefit and win-win results for suppliers, customers and shareholders with professional services.
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