CN116142292A - A control method suitable for man-machine co-driving steering system - Google Patents

Abstract

The invention discloses a control method suitable for a man-machine co-driving steering system. The control method includes an internal torque assist mode, an external angle execution mode and an external angle compensation mode; in the internal torque assist mode, the driver directly And completely control the steering action of the steering wheel, and according to different power calibration, the human-machine co-driving steering system gives the driver different steering feel and road feeling feedback; in the external angle execution mode, the human-machine co-driving The steering system independently executes the steering angle signal from ADAS or ADS to control the lateral direction of the vehicle; in the external angle compensation mode, the steering angle input by the driver is compensated based on the vehicle dynamics characteristics and vehicle handling stability constraints, and dynamically allocated The co-driving steering system and the driver's driving weights, the driver and the co-driving steering system control the vehicle in parallel. The invention can improve the operational performance of the vehicle and reduce the safety risk of the man-machine co-driving system.

Description

A control method suitable for man-machine co-driving steering system

technical field

The invention relates to the technical field of electric steering systems, in particular to a control method suitable for a man-machine co-driving steering system.

Background technique

The man-machine co-driving steering system is a new driving method using electric power assisted steering. The current electric power steering system mainly includes perception sensors, intelligent driving domain controllers, EPS controllers, steering motors, steering gears, angle sensors and torque sensors. wait. The system directly provides steering assistance by the electric power booster, eliminating the need for power steering oil pumps, hoses, hydraulic oil, conveyor belts and pulleys installed on the engine that are necessary for hydraulic power steering systems, which not only saves energy, but also protects the environment. In addition, it also has the characteristics of simple adjustment, flexible assembly and power steering under various conditions. However, the current human-machine co-driving steering system is difficult to accurately identify the driving state of the vehicle, and it is difficult to give the driver driving feedback, and in extreme cases, there will be interaction between the driver and ADAS (Advanced Driver Assistance System) or ADS (Automatic Driving). The confusion of the driving instructions between the vehicles leads to a decrease in the handling performance of the vehicle and increases the safety risk.

Contents of the invention

The purpose of the present invention is to provide a control method suitable for a man-machine co-driving steering system. The invention can improve the operational performance of the vehicle and reduce the safety risk of the man-machine co-driving system.

The technical solution of the present invention: a control method suitable for a man-machine co-driving steering system, the control method includes an internal torque assist mode, an external angle execution mode and an external angle compensation mode;

In the internal torque assist mode, the driver directly and completely controls the steering action of the steering wheel, and according to different power assist calibrations, the man-machine co-driving steering system gives the driver different steering feel and road feel feedback;

In the external angle execution mode, the human-machine co-driving steering system independently executes the steering angle signal from ADAS or ADS to control the lateral direction of the vehicle;

In the external angle compensation mode, the steering angle input by the driver is compensated based on vehicle dynamics characteristics and vehicle handling stability constraints, and the driving weights of the man-machine co-driving steering system and the driver are dynamically assigned, and the driver and human The machine-shared steering system controls the vehicle in parallel.

The above-mentioned control method applicable to the man-machine co-driving steering system, the man-machine co-driving steering system includes a steering wheel, a steering transmission shaft, a steering column, a tie rod, a C-EPS system installed on the steering column, and R-EPS system installed on the steering tie rod;

The C-EPS system includes a first motor, a first ECU and a first TAS sensor; the steering wheel is rigidly connected to the first motor through a column shaft in the steering column; the first motor is controlled by the first EUC and drive, the first motor and the first EUC together form an integrated motor assembly for torque transmission; the first TAS sensor is set between the steering wheel and the column shaft to measure the steering wheel angle and torque signal ;

The R-EPS system includes a driving motor, a second ECU and a second TAS sensor, the driving motor is controlled and driven by the second ECU, the driving motor and the second ECU together form an integrated motor assembly, and the drive cycle is driven by a belt The ball steering mechanism transmits the torque to the steering tie rod, and then drives the steering of the wheels; a second TAS sensor is arranged between the steering transmission shaft and the steering tie rod, and the second TAS sensor is used to measure the output rotation angle of the driving motor;

The first ECU and the second ECU are respectively connected to the public CAN, and the first ECU and the second ECU are also connected through a private CAN; the first ECU and the second ECU both use independent DC12V power supply and power supply harness power supply.

In the aforementioned control method applicable to the man-machine co-driving steering system, the internal torque assist mode is to jointly input the vehicle speed signal v _can output by the public CAN and the torque signal T _Tas output by the second TAS sensor to the software of the first ECU In the application layer, the power assist curve module is preset in the software application layer, and the power assist curve module is used to obtain the driver input various torques and the power assist torque T _a at various vehicle speeds;

At the same time, the second TAS sensor outputs the rotation angle signal θ _{Tas_A} , the rotation angle signal θ _{Tas_A} is passed through a high-pass filter with a filter constant T _s in the software application layer to obtain the filtered steering angular velocity ω _{Tas_A} , and damped in the software application layer The damping torque T _d is obtained after the moment calculation module;

Finally, the assisting torque T _a and the damping torque T _d are superimposed to form the required torque T _cmd of the second motor, and the output torque T _cmd of the second motor acts on the steering wheel.

In the aforementioned control method applicable to the man-machine co-driving steering system, the external angle execution mode is to jointly input the angle command θ _Ref,can from the public CAN and the angle signal θ _{Tas_B} from the first TAS sensor to the first ECU In the software application layer of the first ECU, the angle command θ _{Ref, can} and the angle signal θ _{Tas_B} in the software application layer of the first ECU perform PID closed-loop calculation and angular velocity limit value, and obtain the angular velocity instruction ω _Ref ;

At the same time, the angle signal θ _{Tas_B} of the first TAS sensor passes through a high-pass filter with a filter constant of T _s in the software application layer to obtain the filtered steering angular velocity ω _{Tas_B} , the steering angular velocity ω _{Tas_B} and the angular velocity command ω _Ref pass through the PID closed loop together Calculate, and then obtain the first motor demand torque T _Ext,cmd in the external angle execution mode after the torque limit and the torque rate limit, and act on the steering wheel through the first motor output torque T _Ext,cmd .

In the aforementioned control method applicable to the man-machine co-driving steering system, the external angle compensation mode is to superimpose the output torque T _cmd in the external angle execution mode and the output torque T _{Ext, cmd} in the internal torque assist mode, and finally promote steering wheel steering;

When the human-machine co-driving steering system performs the driving weight distribution function, the driver directly applies the torque T _Driver to the steering wheel, which forms a superimposed torque with the output torque T _cmd generated by the C-EPS system in the external angle execution mode and then inputs it to the R-EPS system, the R-EPS system in the internal torque assist mode performs torque gain and finally pushes the wheels to achieve steering.

The above-mentioned control method applicable to the man-machine co-driving steering system, under emergency conditions, if the output torque T _cmd conflicts with the applied torque T _Driver , the torque weight distribution module is used, and C is assigned according to the scoring mechanism of driver reliability. -The angle control performance of the EPS system is adjusted in real time to complete the dynamic redistribution of the superposition torque input by the R-EPS system, and finally realize the distribution of driving weights between man and machine.

In the aforementioned control method applicable to the man-machine co-driving steering system, when the man-machine co-driving steering system is operating normally, the C-EPS system plays the role of angle closed-loop control, and the R-EPS system is used to control the C-EPS The torque obtained from the closed-loop calculation of the system is used for gain amplification;

When the R-EPS system fails to generate boost torque, the double-closed-loop PID controller and angular velocity limit of the C-EPS system immediately switch to the control parameters in the fault state, increasing the output of the C-EPS system torque, so that the steering system can ensure the execution of the external angle command, and prevent accidents caused by the inability to execute the angle command when the vehicle is under ADS; The C-EPS system immediately exits the external angle execution mode and returns to the internal torque assist mode to realize the driver takeover function;

When the C-EPS system fails to output torque, the R-EPS system immediately enters the external angle execution mode to replace the angle execution function of the C-EPS system to generate steering torque independently to prevent the vehicle from being unable to perform during automatic driving In this state, when the human-machine co-driving steering system detects the driver’s intervention according to the second TAS sensor, the R-EPS system immediately exits the external angle execution mode and returns to the internal torque assist mode to realize The driver takes over the function.

Compared with the prior art, the present invention combines the characteristics of the control structure of the human-machine co-driving technology, and designs three working modes of the man-machine co-driving steering system; through the internal torque assist mode, the driver directly and completely controls the movement of the steering wheel. Steering action, and according to different power assist calibration, can give the driver different steering feel and road feeling feedback, that is, a variety of driving style options. Through the external angle execution mode, the steering angle signal from ADAS or ADS can be independently executed for vehicle lateral control, with driver intervention function and driver's hands-off detection function; through the external angle compensation mode, it can be based on vehicle dynamics characteristics and vehicle handling stability constraints conditions, it can compensate the steering angle input by the driver, and dynamically distribute the driving weight of the CDS system and the driver. The driver and the man-machine co-driving steering system control the vehicle in parallel, which can prevent the instability of the vehicle under extreme working conditions. And improve the handling performance of the vehicle and reduce the safety risk of the human-machine co-driving system.

Description of drawings

Fig. 1 is a schematic structural view of the man-machine co-driving steering system of the present invention;

Fig. 2 is a schematic flow chart of the internal torque assist mode of the present invention;

Fig. 3 is a schematic flow chart of the external angle execution mode of the present invention;

Fig. 4 is a schematic flow chart of the external angle compensation mode of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the examples, but not as a basis for limiting the present invention.

Embodiment: a control method suitable for a man-machine co-driving steering system, as shown in FIG. , Steering tie rod, C-EPS system installed on the steering column and R-EPS system installed on the steering rod;

The C-EPS system includes a first motor (Comuln motor, C-motor), a first ECU (represented as ECUB in the figure, and the ECU is an electronic control unit) and a first TAS sensor (represented as TAS_B, Torque and angle sensor); the steering wheel and the first motor are rigidly connected through the column shaft in the steering column; the first motor is controlled and driven by the first EUC, and the first motor and the first EUC together form an integrated The electric power pack (EPP_B) is used to transmit torque; the first TAS sensor is arranged between the steering wheel and the column shaft to measure the rotation angle and torque signal of the steering wheel;

The R-EPS system includes a drive motor (Rack motor, R-motor), a second ECU (represented as ECUA in the figure, and the ECU is an electronic control unit) and a second TAS sensor (represented as TAS_A in the figure, Torque and angle sensor ), the driving motor is controlled and driven by the second ECU, and the driving motor and the second ECU together form an integrated motor assembly, which drives the recirculating ball steering mechanism through the belt transmission to transmit the torque to the steering tie rod, and then drives the steering of the wheels A second TAS sensor is set between the steering drive shaft and the tie rod, and the second TAS sensor is used to measure the output angle of the drive motor, and then calculate the left and right steering wheel angles according to the Ackerman angle. All the above motor torque and driver torque will eventually be superimposed and output to the steering tie rod to drive the wheels to turn.

The first ECU and the second ECU are respectively connected to the public CAN, and the first ECU and the second ECU are also connected through a private CAN to receive and send necessary message information to realize man-machine co-driving steering The internal and/or external communication of the upper and lower ends of the system; the first ECU and the second ECU are powered by independent DC12V power supply and power supply harness.

In this embodiment, it is known that the steering wheel and the steering wheel of the CDS system can correct the steering wheel input angle of the driver according to its own control algorithm, so as to enhance the steering stability and convenience of the vehicle. Therefore, combined with the control structure characteristics of the man-machine co-driving technology, three working modes of the CDS system are designed:

Including internal torque auxiliary mode (Internal torque auxiliary mode, ITA), external angle execution mode (External angle execution mode, EAE) and external angle compensation mode (External angle compensation mode, EAC);

The internal torque assist mode is the basic function of the CDS system, the driver directly and completely controls the steering action of the steering wheel, and according to different power assist calibrations, the man-machine co-driving steering system can give the driver different steering feel and Road feel feedback, that is, options for various driving styles;

In the external angle execution mode, the man-machine co-driving steering system independently executes the steering angle signal from ADAS or ADS for lateral control of the vehicle, and has driver intervention functions and driver hands-off detection functions;

In the external angle compensation mode, the steering angle input by the driver is compensated based on vehicle dynamics characteristics and vehicle handling stability constraints, and the driving weights of the man-machine co-driving steering system and the driver are dynamically assigned, and the driver and human The machine-co-driving steering system controls the vehicle in parallel, which can prevent the instability of the vehicle under extreme working conditions, improve the handling performance of the vehicle, and reduce the safety risks of the man-machine co-driving system.

Specifically, as shown in FIG. 2, the main function of the internal torque assist mode is to provide the driver with auxiliary steering torque, reduce the steering torque required by the driver, and improve the handling convenience of the vehicle. The basic calculation method The vehicle speed signal _vcan output by the public CAN and the torque signal T _Tas output by the second TAS sensor are jointly input to the software application layer of the first ECU, and the assist curve module is preset in the software application layer, and the assist curve module is used to Obtain driver input torques and assist torque T _a under various vehicle speeds, and realize various steering characteristics of the CDS system in which steering torque increases with vehicle speed and input torque.

At the same time, the second TAS sensor outputs the rotation angle signal θ _{Tas_A} , the rotation angle signal θ _{Tas_A} is passed through a high-pass filter with a filter constant T _s in the software application layer to obtain the filtered steering angular velocity ω _{Tas_A} , and damped in the software application layer The damping torque T _d is obtained after the torque calculation module, so as to realize the control effect of the steering feeling agile and stable. It should be noted that the calculation of the damping torque can be calculated from relevant parameters such as the steering wheel angle, steering angular velocity, and vehicle speed based on kinematics knowledge, and it is only necessary to set the corresponding program in the damping torque calculation module.

Finally, the assisting torque T _a and the damping torque T _d are superimposed to form the required torque T _cmd of the second motor, and the output torque T _cmd of the second motor acts on the steering wheel.

As shown in Figure 3, the external angle execution mode is to execute the angle command from the CAN line, that is, the advanced driver assistance system (Advanced driver assistance system, ADAS) or the automatic driving system (Automatic driving system, ADS) to the steering system Directly send the rotation angle command to realize the steering in ADAS or ADS mode. The basic algorithm is to input the angle command θ _Ref,can from the public CAN and the angle signal θ _{Tas_B} from the first TAS sensor to the software of the first ECU In the application layer, in the software application layer of the first ECU, the angle command θ _{Ref, can} and the angle signal θ _{Tas_B} are executed PID closed-loop calculation (the PID closed-loop calculation is carried out by the PID controller) and the angular velocity limit value to obtain the angular velocity instruction ω _Ref ;

At the same time, the angle signal θ _{Tas_B} of the first TAS sensor passes through a high-pass filter with a filter constant of T _s in the software application layer to obtain the filtered steering angular velocity ω _{Tas_B} , the steering angular velocity ω _{Tas_B} and the angular velocity command ω _Ref pass through the PID closed loop together Calculate, and then obtain the first motor demand torque T _Ext,cmd in the external angle execution mode after the torque limit and the torque rate limit, and act on the steering wheel through the first motor output torque T _Ext,cmd .

As shown in Figure 4, the external angle compensation mode is when the redundant steering system composed of the C-EPS system and the R-EPS system is in the ADAS or ADS state, the C-EPS system is generally in the EAE state, and the R-EPS system is generally in the EAE state. Under ITA, the external angle compensation mode is to superimpose the output torque T _cmd in the external angle execution mode and the output torque T _{Ext, cmd} in the internal torque assist mode, and finally push the steering wheel to turn;

Specifically, when the CDS system is working normally and the C-EPS system is in EAE, the double closed-loop PID algorithm _{described above} is used to convert the external angle command into the first motor The output torque T _{Ext, cmd} on the steering column of the steering column, T _{Ext, cmd} is transmitted to the R-EPS system through the intermediate shaft. At this time, the R-EPS system is under ITA, and the T _cmd generated by the C-EPS system acts on the TAS_A sensor in the R-EPS system to output the steering angle θ _{Tas_A} and the torque T _{Tas_A} , and then through the assist curve and the damping calculation module The steering assist torque T _cmd is obtained and superimposed with T _{Ext, cmd} to finally push the wheels to turn, and realize the closed-loop control of the external angle command, and realize the execution of the EAE control command of the redundant system.

When the human-machine co-driving steering system performs the driving weight distribution function, the driver directly applies the torque T _Driver to the steering wheel, which forms a superimposed torque with the output torque T _cmd generated by the C-EPS system in the external angle execution mode and then inputs it to the R-EPS system, the R-EPS system in the internal torque assist mode performs torque gain and finally pushes the wheels to achieve steering. In emergency conditions, if the output torque T _cmd conflicts with the applied torque T _Driver , the torque weight distribution module is used to adjust the angle control performance of the C-EPS system in real time according to the driver reliability scoring mechanism to complete the R-EPS system. The dynamic redistribution of the superimposed torque input by the EPS system finally realizes the distribution of driving weight between man and machine.

In this embodiment, when the human-machine co-driving steering system is operating normally, the C-EPS system plays the role of angle closed-loop control, and the R-EPS system is used to gain the torque obtained by the closed-loop calculation of the C-EPS system the effect of amplification;

2. When the R-EPS system breaks down and cannot generate boost torque, the double-closed-loop PID controller and angular velocity limit of the C-EPS system immediately switch to the control parameters in the fault state, increasing the C-EPS system Output torque, so that the steering system can ensure the execution of the external angle command, and prevent accidents caused by the inability to execute the angle command when the vehicle is under ADS; , the C-EPS system immediately exits the external angle execution mode and returns to the internal torque assist mode to realize the driver takeover function;

When the C-EPS system fails to output torque, the R-EPS system immediately enters the external angle execution mode to replace the angle execution function of the C-EPS system to generate steering torque independently to prevent the vehicle from being unable to perform during automatic driving In this state, when the human-machine co-driving steering system detects the driver’s intervention according to the second TAS sensor, the R-EPS system immediately exits the external angle execution mode and returns to the internal torque assist mode to realize The driver takes over the function.

To sum up, the present invention combines the characteristics of the control structure of the man-machine co-driving technology, and designs three working modes of the man-machine co-driving steering system, thereby improving the operability of the vehicle and reducing the cost of the man-machine co-driving system. Security Risk.

Claims (7)

1. A control method suitable for a man-machine co-driving steering system is characterized by comprising the following steps of: the control method comprises an internal torque auxiliary mode, an external angle execution mode and an external angle compensation mode;

in the internal torque auxiliary mode, a driver directly and completely controls the steering action of the steering wheel and calibrates according to different power aids, and the man-machine co-driving steering system gives different steering handfeel and road feel feedback to the driver;

in the external angle execution mode, the man-machine co-driving steering system independently executes steering angle signals from ADAS or ADS to carry out vehicle transverse control;

in the external angle compensation mode, the rotation angle input by the driver is compensated based on the vehicle dynamics characteristic and the vehicle operation stability constraint condition, the driving weight of the man-machine co-driving steering system and the driver is dynamically distributed, and the driver and the man-machine co-driving steering system control the vehicle in parallel.

2. The control method for a co-driving steering system for a man-machine according to claim 1, wherein: the man-machine co-driving steering system comprises a steering wheel, a steering transmission shaft, a steering column, a steering tie rod, a C-EPS system arranged on the steering column and an R-EPS system arranged on the steering tie rod;

the C-EPS system comprises a first motor, a first ECU and a first TAS sensor; the steering wheel is rigidly connected with the first motor through a pipe column shaft in the steering pipe column; the first motor is controlled and driven by the first EUC, and the first motor and the first EUC form an integrated motor assembly together for transmitting torque; a first TAS sensor is arranged between the steering wheel and the tubular column shaft and used for measuring the rotation angle and torque signals of the steering wheel;

the R-EPS system comprises a driving motor, a second ECU and a second TAS sensor, wherein the driving motor is controlled and driven by the second ECU, the driving motor and the second ECU jointly form an integrated motor assembly, and torque is transmitted to a steering transverse pull rod through a belt transmission driving recirculating ball steering mechanism, so that steering of wheels is driven; a second TAS sensor is arranged between the steering transmission shaft and the steering tie rod and is used for measuring and obtaining the output rotation angle of the driving motor;

the first ECU and the second ECU are respectively connected with the public CAN, and the first ECU and the second ECU are also connected through the private CAN; the first ECU and the second ECU are powered by independent DC12V power supply and power supply line bundles.

3. The control method for a co-driving steering system for a man-machine according to claim 2, wherein: the internal torque auxiliary dieBy outputting a vehicle speed signal v from a common CAN _can And a torque signal T output by a second TAS sensor _Tas The method comprises the steps of commonly inputting the power-assisted curve module into a software application layer of a first ECU, presetting the power-assisted curve module in the software application layer, and obtaining the power-assisted moment T of a driver inputting various moments and various vehicle speeds by using the power-assisted curve module _a ；

At the same time, the second TAS sensor outputs a rotation angle signal theta _{Tas_A} The rotation angle signal theta _{Tas_A} Through a filtering constant T in the software application layer _s To obtain the filtered steering angular velocity omega _{Tas_A} And obtaining the damping moment T through a damping moment calculation module in the software application layer _d ；

Finally, the power-assisted moment T _a And damping moment T _d Superposition of the required torque T of the second motor _cmd And outputs torque T through the second motor _cmd Acting on the steering wheel.

4. The control method for a co-driving steering system for a man-machine according to claim 2, wherein: the external angle execution mode is implemented by an angle command theta from a common CAN _Ref，can And an angle signal θ from the first TAS sensor _{Tas_B} Commonly input to the software application layer of the first ECU, the angle command theta in the software application layer of the first ECU _Ref，can And an angle signal theta _{Tas_B} Executing PID closed loop calculation and angular velocity limit value to obtain angular velocity command omega _Ref ；

At the same time the angle signal theta of the first TAS sensor _{Tas_B} In the software application layer, a filtering constant is T _s To obtain the filtered steering angular velocity omega _{Tas_B} Steering angular velocity omega _{Tas_B} And angular velocity command ω _Ref Then the first motor required torque T under the external angle execution mode is obtained after PID closed loop calculation and then the torque limit value and the torque rate limit value _Ext，cmd And outputs torque T through the first motor _Ext，cmd Acting on the steering wheel.

5. The control method for a co-driving steering system for a man-machine according to claim 2, wherein: the external angle compensation mode is to output torque T in an external angle execution mode _cmd Output torque T in internal torque assist mode _Ext，cmd Superposing, and finally pushing the steering wheel to steer;

when the man-machine co-driving steering system executes the driving weight distribution function, the driver directly applies the torque T to the steering wheel _Driver Output torque T generated in external angle execution mode with C-EPS system _cmd And after forming the superimposed moment, the superimposed moment is input into the R-EPS system, and the R-EPS system in the internal moment auxiliary mode performs moment gain and finally pushes the wheels to realize steering.

6. The control method for a co-driving steering system for a man-machine according to claim 5, wherein: in emergency condition, if the torque T is output _cmd And applying a moment T _Driver And if the conflict occurs, adopting a moment weight distribution module, and adjusting the angle control performance of the C-EPS system in real time according to a scoring mechanism of the reliability of the driver to finish the dynamic redistribution of the superposition moment input by the R-EPS system, thereby finally realizing the distribution of the driving weight between the human and the machine.

7. The control method for a co-driving steering system for a man-machine according to claim 2, wherein: when the man-machine co-driving steering system normally operates, the C-EPS system plays a role in angle closed-loop control, and the R-EPS system is used for performing gain amplification on the torque obtained by closed-loop calculation of the C-EPS system;

when the R-EPS system fails and cannot generate a torque, the double closed-loop PID controller and the angular speed limit of the C-EPS system are immediately switched to control parameters under a failure state, so that the output torque of the C-EPS system is increased, the steering system ensures the execution of external angle instructions, and accidents caused by the fact that the vehicle cannot execute the angle instructions under the ADS are prevented; in this state, when the man-machine co-driving steering system detects the intervention of the driver according to the first TAS sensor, the C-EPS system immediately exits the external angle execution mode and returns to the internal torque auxiliary mode to realize the driver take over function;

when the C-EPS system fails and cannot output torque, the R-EPS system immediately enters an external angle execution mode to replace an angle execution function of the C-EPS system, and steering torque is generated independently, so that accidents caused by incapability of executing an angle instruction when a vehicle is driven automatically are prevented; in this state, when the man-machine co-driving steering system detects the intervention of the driver according to the second TAS sensor, the R-EPS system immediately exits the external angle execution mode and returns to the internal torque assist mode to realize the driver takeover function.

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