CN107901979A - A kind of electro-hydraulic active steering road feel control system of automobile and its control method - Google Patents

Abstract

The invention discloses a kind of electro-hydraulic active steering road feel control system of automobile and its control method, including machine driving module, electric boosted module, hydraulic module, sensor assembly and control module.Electric boosted module is according to road surface actual conditions, suitable assist torque is applied by arc linear motor, give driver feedback really and accurately information of road surface, and propose a kind of road feel control method, by estimating vehicle states information, respectively perform intervene with not performing active steering when, correct preferable power-assisted gain and go forward side by side walking along the street sensing control system, system rejection to disturbance ability is enhanced, ensures riding stability.

Description

A vehicle electro-hydraulic active steering road feel control system and control method thereof

technical field

The invention relates to an automobile technology, in particular to an automobile steering system technology, in particular to an automobile electro-hydraulic active steering road feel control system and a control method thereof.

Background technique

A car is a complex closed-loop system composed of "people-vehicle-road". The driver feels the feedback information from the road surface through the steering system, which is called steering sense. When the car is turning, the righting torque generated by the tires is transmitted to the driver through the steering system, and the information transmitted to the driver also includes information such as road surface roughness, road surface adhesion, steering degree, tire load and air pressure. In order to reduce the driver's burden, the existing automobile steering system adopts power steering, that is, assists steering through an additional power source. However, the assist torque and steering feel are a pair of contradictions. When the road surface straightening torque remains constant, the greater the assist torque, the worse the steering feel the driver will get.

The steering system not only transmits the torque, but also transmits the angle of rotation. The emerging electro-hydraulic active steering system can control the force and angle separately, adjust the steering ratio in real time, and obtain good steering performance. When the electro-hydraulic active steering system uses a hydraulic module to adjust the angle of the additional front wheels, it will inevitably affect the force transmission characteristics of the system, making the driver's road feeling deviate from the actual road conditions, which is not conducive to the driver's grasp of vehicle conditions and road conditions, and affects driving. Safety.

At present, domestic and foreign researches on road feel control focus on Electric Power Steering (EPS) Steering by Wire (SBW) system. CN101081626B adopts booster control, centering control and damping control to directly control road feel of EPS. CN102923185B passes The single-chip microcomputer carries out the road feeling control to the electro-hydraulic power steering system, and CN105083373A provides the steering-by-wire simulated road feel through the parameter estimation method; but for the electro-hydraulic active steering system, there is no public report on its road feel control, because the electro-hydraulic active steering system Due to the structural complexity and coupling relationship, the above existing road feeling control methods cannot be directly applied to the electro-hydraulic active steering system. Therefore, for the electro-hydraulic active steering system, a road feeling control strategy is proposed to give full play to the advantages of its variable transmission ratio, so that the driver can get a better road feel, which is of great significance for the actual product development.

Contents of the invention

The purpose of the present invention is to provide an electro-hydraulic active steering sense control system and a control method thereof to overcome the problems existing in the prior art. The electro-hydraulic active steering road feel control system proposed by the present invention can apply an appropriate boost torque according to the actual road surface conditions when performing active steering, and feed back real and accurate road surface information to the driver; the matched road feel control method can enhance System anti-interference ability, improve system robustness.

One of technical solutions of the present invention is:

An electro-hydraulic active steering road feel control system, comprising: a mechanical transmission module, an electric power assist module, a hydraulic module, a sensor module and a control module;

The mechanical transmission module includes a steering wheel, a steering column, a recirculating ball steering gear, a steering rocker arm, a steering straight rod, a steering trapezoid and wheels connected in sequence;

The steering straight rod includes a hydraulic cylinder, a piston, and a straight rod;

The casing of the hydraulic cylinder is fixedly connected to the output end of the recirculating ball steering gear through the steering rocker arm, and the casing is provided with an oil inlet and an oil outlet; the piston is assembled in the above hydraulic cylinder, and straight rods are fixedly installed at both ends of the piston. The rear end of the straight tie rod is connected to the steering trapezoid and the wheels;

The electric booster module includes a booster motor and a coupling sleeve mechanism; the steering assist part of the booster motor is installed on the steering column, and the coupling sleeve mechanism is used to connect the steering column and the booster motor;

The booster motor adopts an arc-shaped linear motor. The primary stage of the arc-shaped linear motor is electrically connected to the control module, and the secondary is arranged side by side on the steering column of the mechanical transmission module. The mechanism is connected with the upper and lower ends of the arc linear motor secondary;

The hydraulic module includes an oil storage tank, a drive motor, a hydraulic pump, and a proportional reversing valve;

The hydraulic pump drive motor is connected to the hydraulic pump, and the low-pressure oil in the oil storage tank is converted into high-pressure oil after the action of the hydraulic pump and flows to the proportional reversing valve;

The proportional reversing valve distributes the direction and flow of high-pressure oil, communicates with the hydraulic cylinder through the oil pipe, changes the pressure on both sides of the piston, and drives the piston to move relative to the hydraulic cylinder

The sensor module includes a rotation angle sensor, a torque sensor, a vehicle speed sensor, a wheel speed sensor, a yaw rate sensor, and a lateral acceleration sensor;

The rotation angle sensor is installed on the steering wheel and is electrically connected with the control module to provide a rotation angle signal input by the driver;

The torque sensor is installed on the steering column and electrically connected with the control module to provide the actual torque signal of the steering column;

The vehicle speed sensor, wheel speed sensor, yaw rate sensor, and lateral acceleration sensor are installed on the vehicle, and are respectively electrically connected to the control module to provide vehicle speed, wheel speed, yaw rate, and lateral acceleration signals;

The control module includes a variable transmission module, a vehicle state estimation module, a return torque estimation module, an additional displacement control module, a torque-displacement correction module, a booster gain module, and a booster gain correction module; each module coordinates and controls the booster motor and the piston According to the road surface information and vehicle status, it provides power-assist torque to improve driving comfort.

The second technical scheme of the present invention is:

A control method for an automotive electro-hydraulic active steering road feel control system, comprising the following steps:

1. The control module acquires vehicle status information, including:

1.1 The state estimation module 31 receives the lateral acceleration signal 25 and the wheel speed signal 35, uses the Kalman filter method to estimate the longitudinal force and lateral force on the wheel according to the vehicle load and tire parameters, and calculates the influence coefficient of the lateral force 36. The righting moment estimation module 33 calculates the righting moment 37 according to the lateral force influence coefficient;

1.2 The booster gain module 29 receives the vehicle speed signal 23 and the torque signal 22, and calculates the ideal booster gain 38 in combination with the normalizing torque 37;

1.3 The variable transmission module 34 receives the vehicle speed signal 23, the yaw rate 24 and the rotation angle signal 21, calculates the ideal transmission ratio 39, and judges whether to execute the active steering intervention operation according to the active steering control strategy;

2. Road feel control when active steering intervention is not performed

2.1. Let T _r be the centering torque, T _f the friction torque, T _a the assist torque, and T _p the torque felt by the driver, then T _r = T _f +T _a +T _p . Control, processed with a fixed value, the booster gain calculation module calculates the ideal torque felt by the driver according to the input vehicle speed and torque signals;

2.2 The assist gain calculation module combines the return torque input by the return torque estimation module to calculate the required assist torque. According to the actual current signal of the arc-shaped linear motor fed back, the PID control algorithm based on BP neural network is adopted to dynamically adjust the ideal Boost gain; when the current increases, the torque output by the arc-shaped linear motor increases, and through the action of the steering column, the torque felt by the driver decreases, and the opposite happens when the current decreases;

3. Road feel control when performing active steering intervention

3.1 The additional displacement control module 32 sends out the driving motor control signal and the proportional reversing valve control signal to control the driving motor to drive the hydraulic pump to generate high-pressure oil, which enters the hydraulic cylinder through the flow distribution of the proportional reversing valve, and changes the pressure difference on both sides of the piston so that The straight tie rod connected to the piston outputs an additional displacement of 40 relative to the hydraulic cylinder, and the additional displacement of the straight tie rod is converted into an additional front wheel angle through the steering trapezoidal mechanism to complete active steering intervention;

3.2 The torque-displacement correction module 30 receives the additional displacement 40 output by the additional displacement control module, uses the Hinf robust control method to correct the booster gain, and outputs a current correction signal 41;

3.3 The booster gain correction module 44 receives the current correction signal 41 and the ideal booster gain 38 respectively, and linearly superimposes the two, and outputs the control signal 26 of the arc-shaped linear motor; the primary arc-shaped linear motor is under the action of the corrected control signal 26 , the output power steering torque is 42, through the arc-shaped linear motor secondary and the steering column, it acts on the recirculating ball steering gear and transmits it to the wheels;

Preferably, the method for calculating the ideal boost gain in step 1.2 and the ideal torque felt by the driver in step 2.1 is:

T _pbest =k _a *(T _d -T ₀ )

In the formula: T _pbest is the ideal torque felt by the driver, T _d is the input torque of the driver, T ₀ is the torque at the beginning of assisting, k _a is the ideal boosting gain, T _max is the maximum boosting input torque, T _f is the maximum torque, k _b is the slope of the assist characteristic curve;

Preferably, the PID control algorithm based on BP neural network tuning in said step 2.2, the specific steps are as follows:

2.2.1. Determine the initial structural parameters of the BP neural network, including: the number of hidden layers m, the number of hidden nodes, the inertia coefficient λ, the learning rate α, the number of input nodes n, the number of output nodes q, and initialize the weighting coefficients of each layer w _i i = 1,2,3, set the sampling number k=1

2.2.2. Sampling to obtain the given boost gain R(t) and actual boost gain Q(t) respectively, calculate the current time deviation as E(t)=R(t)-Q(t) and each layer of BP neural network The input and output of neurons, the output parameters are the proportional, integral and differential parameters of PID control;

2.2.3. The BP neural network performs online learning and adjustment, and performs adaptive adjustment to the weight coefficients w _i i = 1, 2, 3 of each layer; set k = k+1, and repeat the above step 2.2.2.

Beneficial effects of the present invention:

The electro-hydraulic active steering road feel control system proposed by the present invention can change the transmission ratio of the steering system according to different driving conditions of the car, and at the same time of performing active steering, it can overcome the impact of the torque transfer characteristic change caused by the variable transmission ratio module on the steering road feel. According to the actual situation of the road surface and the state of the vehicle, an appropriate boost torque is applied to feed back real and accurate road surface information to the driver.

The road feeling control method provided by the invention greatly enhances the anti-interference ability of the system, ensures driving stability, obtains better steering road feel, and has better system robustness.

The present invention uses an arc-shaped linear motor to assist and directly drives the steering column to provide steering assist, which reduces the friction loss caused by the use of a common motor that needs to be matched with a deceleration mechanism. The structure is simple, easy to control, and has good starting stability;

The present invention adopts the method of assisting the steering column in front of the recirculating ball steering gear. The power assist torque output by the arc-shaped linear motor is transmitted to the wheels through the recirculating ball steering gear. The volume and mass of the motor can be reduced, which is convenient for arrangement in the cab.

Description of drawings

Fig. 1 is a schematic structural block diagram of the electro-hydraulic active steering road feel control system of the present invention.

Fig. 2 is a control schematic diagram of the present invention.

In the figure, 1-steering wheel, 2-rotation angle sensor, 3-torque sensor, 4-steering column, 5-secondary arc linear motor, 6-coupling sleeve mechanism, 7-recirculating ball steering unit, 8-steering straight line Tie rod, 9-steering trapezoid, 10-wheel, 11-proportional reversing valve, 12-hydraulic pump, 13-drive motor, 14-fuel tank, 15-straight pull rod, 16-hydraulic cylinder, 17-piston, 18-steering rocker Arm, 19-control module, 20-arc linear motor primary, 21-angle signal, 22-torque signal, 23-vehicle speed signal, 24-yaw rate signal, 25-lateral acceleration signal, 26-arc linear Motor control signal, 27-proportional reversing valve control signal, 28-drive motor control signal, 29-assist gain calculation module, 30-torque-displacement correction module, 31-state estimation module, 32-additional displacement module, 33- Alignment torque estimation module, 34-variable transmission module, 35-wheel speed signal, 36-lateral force influence coefficient, 37-alignment torque, 38-ideal power boost gain, 39-ideal transmission ratio, 40-additional displacement, 41 - current correction signal, 42 - assist torque;

Detailed ways

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the embodiments and accompanying drawings, and the contents mentioned in the embodiments are not intended to limit the present invention.

Embodiment one.

As shown in Figure 1.

An automotive electro-hydraulic active steering road feel control system, which mainly consists of a steering wheel 1, a steering column 4, an arc-shaped linear motor, a coupling sleeve mechanism 6, a recirculating ball steering device 7, a steering straight rod 8, a steering trapezoid 9 and a control module 19 components, the steering wheel is installed on the upper end of the steering column 4, the secondary 5 of the arc-shaped linear motor is installed on the steering column 4, the secondary 5 of the arc-shaped linear motor is controlled by the primary 20 of the arc-shaped linear motor, and the arc-shaped linear motor The primary 20 of the linear motor is controlled by the control module 19, and the control module 19 generates an assist torque driving signal according to the signals received from the vehicle and steering sensors. The steering column 4 is connected to the upper and lower ends of the arc-shaped linear motor through two upper and lower coupling sleeve mechanisms 6, and the recirculating ball steering gear 7 is connected to the housing of the hydraulic cylinder 16 through the steering rocker arm 18, and the hydraulic cylinder 16 is equipped with a piston 17, Both sides of the piston 17 are respectively connected to the steering trapezoid 9 through a direct rod 15, the steering trapezoid 9 is connected to the wheel 10, the hydraulic cylinder 16 is controlled by the proportional reversing valve 11, and the proportional reversing valve 11 is controlled by the control module 19, The control module 19 controls the oil inlet channel of the proportional reversing valve 11 to move the piston to the left or right to realize left or right hydraulic steering power boost. The hydraulic oil of the proportional reversing valve 11 is drawn from the oil tank 14 by the hydraulic pump 12 Pumping in, the hydraulic pump 12 is driven by the driving motor 13, and the driving motor 13 is also controlled by the control module 19. The control module 19 makes one of the arc direct motor and the hydraulic cylinder to increase the force alone or both simultaneously according to the signals obtained by the sensors. Judgment of boost and output control signal.

Embodiment two.

Refer to Figure 1.

An automotive electro-hydraulic active steering road feel control system, including: a mechanical transmission module, an electric power assist module, a hydraulic module, a sensor module and a control module; wherein:

The mechanical transmission module includes the steering wheel, steering column, recirculating ball steering gear, steering rocker arm, steering straight rod, steering trapezoid and wheels connected in sequence; the steering straight rod includes hydraulic cylinders, pistons, and straight rods; the shell of the hydraulic cylinder passes through the steering rocker. The arm is fixedly connected to the output end of the recirculating ball steering gear, and the casing is provided with an oil inlet and an oil outlet; the piston is assembled in the above-mentioned hydraulic cylinder, and the two ends of the piston are fixedly installed with a straight rod, and the rear end of the straight rod is connected to the steering trapezoid and the wheel; The booster module includes a booster motor and a coupling sleeve mechanism; the booster motor adopts an arc-shaped linear motor, and the primary side of the arc-shaped linear motor is electrically connected to the control module, and the secondary side is arranged on the steering column of the mechanical transmission module. The steering column is divided into The upper and lower sections are respectively connected to the upper and lower ends of the arc-shaped linear motor secondary through the coupling sleeve mechanism;

The hydraulic module includes an oil storage tank, a drive motor, a hydraulic pump, and a proportional reversing valve; the driving motor of the hydraulic pump is connected to the hydraulic pump, and the low-pressure oil in the oil storage tank is converted into high-pressure oil by the hydraulic pump and flows to the proportional reversing valve; The reversing valve distributes the direction and flow of high-pressure oil, communicates with the hydraulic cylinder through the oil pipe, changes the pressure on both sides of the piston, and drives the piston to move relative to the hydraulic cylinder

The sensor module includes a rotation angle sensor, a torque sensor, a vehicle speed sensor, a wheel speed sensor, a yaw rate sensor, and a lateral acceleration sensor; the rotation angle sensor is installed on the steering wheel and is electrically connected with the control module to provide a rotation angle signal input by the driver The torque sensor is installed on the steering column and electrically connected with the control module to provide the actual torque signal of the steering column; the vehicle speed sensor, wheel speed sensor, yaw rate sensor, and lateral acceleration sensor are installed on the vehicle, They are electrically connected with the control module respectively and provide signals of vehicle speed, wheel speed, yaw rate and lateral acceleration;

The control module includes a variable transmission module, a vehicle state estimation module, a return torque estimation module, a variable transmission module, an additional displacement control module, a torque-displacement correction module, a booster gain module, and a booster gain correction module; the coordination of each part of the control module See embodiment three for the action process and rules.

Embodiment three.

as shown in picture 2.

A vehicle electro-hydraulic active steering road feeling control method, comprising the following steps:

1. The control module acquires vehicle status information, including:

1.1 The state estimation module 31 receives the lateral acceleration signal 25 and the wheel speed signal 35, uses the Kalman filter method to estimate the longitudinal force and lateral force on the wheel according to the vehicle load and tire parameters, and calculates the influence coefficient of the lateral force 36. The righting moment estimation module 33 calculates the righting moment 37 according to the lateral force influence coefficient;

1.2 The booster gain module 29 receives the vehicle speed signal 23 and the torque signal 22, and calculates the ideal booster gain 38 in combination with the normalizing torque 37;

1.3 The variable transmission module 34 receives the vehicle speed signal 23, the yaw rate 24 and the rotation angle signal 21, calculates the ideal transmission ratio 39, and judges whether to execute the active steering intervention operation according to the active steering control strategy;

2. Road feel control when active steering intervention is not performed

2.1. Let T _r be the centering torque, T _f the friction torque, T _a the assist torque, and T _p the torque felt by the driver, then T _r = T _f +T _a +T _p . Control, processed with a fixed value, the booster gain calculation module calculates the ideal torque felt by the driver according to the input vehicle speed and torque signals;

2.2 The assist gain calculation module combines the return torque input by the return torque estimation module to calculate the required assist torque. According to the actual current signal of the arc-shaped linear motor fed back, the PID control algorithm based on BP neural network is adopted to dynamically adjust the ideal Boost gain; when the current increases, the torque output by the arc-shaped linear motor increases, and through the action of the steering column, the torque felt by the driver decreases, and the opposite happens when the current decreases;

3. Road feel control when performing active steering intervention

3.1 The additional displacement control module 32 sends out the driving motor control signal and the proportional reversing valve control signal to control the driving motor to drive the hydraulic pump to generate high-pressure oil, which enters the hydraulic cylinder through the flow distribution of the proportional reversing valve, and changes the pressure difference on both sides of the piston so that The straight tie rod connected to the piston outputs an additional displacement of 40 relative to the hydraulic cylinder, and the additional displacement of the straight tie rod is converted into an additional front wheel angle through the steering trapezoidal mechanism to complete active steering intervention;

3.2 The torque-displacement correction module 30 receives the additional displacement 40 output by the additional displacement control module, uses the Hinf robust control method to correct the booster gain, and outputs a current correction signal 41;

3.3 The booster gain correction module 44 receives the current correction signal 41 and the ideal booster gain 38 respectively, and linearly superimposes the two, and outputs the control signal 26 of the arc-shaped linear motor; the primary arc-shaped linear motor is under the action of the corrected control signal 26 , the output power steering torque is 42, through the arc-shaped linear motor secondary and the steering column, it acts on the recirculating ball steering gear and transmits it to the wheels;

Wherein, the method for calculating the ideal power boost gain in step 1.2 and the ideal torque felt by the driver in step 2.1 is:

In the formula: T _pbest is the ideal torque, T _d is the driver input torque, T ₀ is the torque at the beginning of assisting, k _a is the ideal assisting gain, T _max is the maximum assisting input torque, T _f is the maximum torque , k _b is the slope of the boost characteristic curve;

Wherein, the PID control algorithm based on BP neural network tuning in step 2.2, the specific steps are as follows:

2.2.1. Determine the initial structural parameters of the BP neural network, including: the number of hidden layers m, the number of hidden nodes, the inertia coefficient λ, the learning rate α, the number of input nodes n, the number of output nodes q, and initialize the weighting coefficients of each layer w _i i = 1,2,3, set the sampling number k=1

2.2.2. Sampling to obtain the given boost gain R(t) and actual boost gain Q(t) respectively, calculate the current time deviation as E(t)=R(t)-Q(t) and each layer of BP neural network The input and output of neurons, the output parameters are the proportional, integral and differential parameters of PID control;

2.2.3. The BP neural network performs online learning and adjustment, and performs adaptive adjustment to the weight coefficients w _i i = 1, 2, 3 of each layer; set k = k+1, and repeat the above step 2.2.2.

There are many specific application approaches of the present invention, and the above description is only a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principles of the present invention. Improvements should also be regarded as the protection scope of the present invention.

The parts not involved in the present invention, such as the specific structure and installation and use of the hydraulic booster part and the arc-shaped linear motor, the steering mechanism, the steering wheel steering column, the installation of various sensors and signal acquisition, etc. are the same as the prior art or can adopt the prior art to achieve.

Claims (5)

1. A kind of 1. electro-hydraulic active steering road feel control system of automobile, it is characterised in that including：It is machine driving module, electric boosted Module, hydraulic module, sensor assembly and control module；

   The machine driving module include sequentially connected steering wheel, steering column, ball-and-nut steering gear, pitman arm, turn To Drag link, steering trapezium and wheel；The steering drag link includes hydraulic cylinder, piston, Drag link, the shell of the hydraulic cylinder It is fixedly connected by pitman arm with ball-and-nut steering gear output terminal, oil inlet and oil outlet is offered on shell；The piston It is assemblied in above-mentioned hydraulic cylinder, Drag link, vertical pulling rod rear end connection steering trapezium and wheel is fixedly mounted in piston both ends；

   The electric boosted module includes assist motor, coupling sleeve mechanism；The power steering of assist motor, which is partially installed on, to be turned To on tubing string, coupling sleeve mechanism is used to connect steering column and assist motor；

   The hydraulic module includes oil storage tank, driving motor, hydraulic pump, proportional reversing valve, and the hydraulic pump drive motor connects Connect hydraulic pump, the low pressure oil in oil storage tank is converted to high pressure oil after hydraulic pressure pumping action and flows to proportional reversing valve；The ratio Reversal valve distributes high pressure oil direction and uninterrupted, is communicated by oil pipe and above-mentioned hydraulic cylinder, and the pressure for changing piston both sides is big It is small, the cylinder movement of driving piston opposing hydraulic；

   The sensor assembly includes rotary angle transmitter, torque sensor, vehicle speed sensor, wheel speed sensors, yaw angle speed Spend sensor, lateral acceleration sensor；The rotary angle transmitter is installed on the steering wheel and electrically connected with the control module Connect, there is provided the angular signal of driver's input；The torque sensor is on steering column and electric with the control module Gas connects, there is provided steering column actual torque signal；The vehicle speed sensor, wheel speed sensors, yaw-rate sensor, side It is installed on to acceleration transducer on vehicle, is electrically connected respectively with the control module and speed is provided, wheel speed, yaw angle speed Degree, lateral acceleration signal；

   The control module includes becoming transmission module, whole vehicle state estimation module, aligning torque estimation module, additional displacement control Module, torque-displacement correction module, power-assisted gain module and power-assisted gain-boosted op amp module；Each module coordination controls assist motor And piston action, assist torque is provided according to information of road surface and vehicle-state, improves the comfort of driving.
2. 2. the electro-hydraulic active steering road feel control system of automobile according to claim 1, it is characterised in that the assist motor Using arc linear motor, arc linear motor is primary to be electrically connected with control module, and secondary is power steering output par, c, and Row are arranged on the steering column of the machine driving module, and steering column is secondary by coupling sleeve mechanism and arc linear motor Both ends connect.
3. 3. a kind of steering response control method of the electro-hydraulic active steering road feel control system of automobile based on described in claim 1, It is characterized in that it is as follows including step：

   First, control module obtains car status information：

   1.1 state estimation modules (31) receive lateral acceleration signal (25) and wheel speed signal (35), according to car load and wheel Tire parameter, the longitudinal force and lateral force suffered by wheel are estimated using kalman filter method, and calculate lateral force influence system Number (36), aligning torque estimation module 33 influence coefficient according to lateral force and calculate aligning torque 37；

   1.2 power-assisted gain modules (29) receive speed signal (23) and dtc signal (22), with reference to aligning torque (37), calculate Preferable power-assisted gain (38)；

   1.3, which become transmission module (34), receives speed signal (23), yaw velocity (24) and angular signal (21), calculates preferable pass Move than (39), and according to active steering control strategy, judge whether to perform active steering intervention operation；

   Wherein：Road feel control method when not performing active steering intervention operation is：

   2.1. T is set_rFor aligning torque, T_fFor moment of friction, T_aFor assist torque, T_pThe torque experienced for driver, then T_r= T_f+T_a+T_p, due to moment of friction with it is unmanageable, handled with fixed value, power-assisted gain calculation module according to the speed of input and Dtc signal, calculates the preferable torque that driver experiences；

   The reason that the aligning torque and step 2.1 of 2.2 power-assisted gain calculation module combination aligning torque estimation modules input calculate Think torque, calculate required assist torque size, according to the arc linear motor actual current signal of feedback, using based on The pid control algorithm that BP neural network is adjusted, dynamic adjust preferable power-assisted gain；When electric current increases, arc linear motor output Torque increase, acted on by steering column, torque that driver experiences reduces, and electric current is then opposite when reducing；

   Perform active steering intervention operation when road feel control method be：

   3.1 additional displacement control modules (32) send driving motor control signal and proportional reversing valve control signal, control driving Motor-driven hydraulic pumps produce high pressure oil, enter hydraulic cylinder by proportional reversing valve assignment of traffic, and it is big to change piston both sides pressure difference It is small, the Drag link opposing hydraulic cylinder that is connected with piston is exported additional displacement (40), and by tie rod linkage by Drag link Additional displacement is converted into additional front wheel angle, completes active steering intervention；

   3.2 torques-displacement correction module (30) receives the additional displacement (40) exported after the effect of additional displacement control module, Power-assisted gain is modified using Hinf robust control methods, output current revise signal (41)；

   3.3 power-assisted gain-boosted op amp modules (44) receive electric current revise signal (41) and preferable power-assisted gain (38) respectively, and to two Person carries out linear superposition, output arc linear motor control signal (26)；Arc linear motor primary is straight in revised arc Under the action of line motor control signal (26), power steering torque (42) is exported, through arc linear motor is secondary and steering column, Act on ball-and-nut steering gear and to wheel transmission.
4. 4. steering response control method according to claim 3, it is characterised in that set T_pbestThe reason experienced for driver Think torque, T_dFor driver's input torque, T₀Torque during to start to provide power-assisted, k_aFor preferable power-assisted gain, T_maxHelped for maximum Power input torque, T_fFor torque capacity, k_bFor the assist characteristic slope of curve；

   Calculate preferable power-assisted gain and the method for desired torque that driver experiences is：
5. 5. steering response control method according to claim 3, it is characterised in that described to be adjusted based on BP neural network Pid control algorithm, comprises the following steps that：

   (1) BP neural network initial structure parameter is determined, including：Hide number of layers m, concealed nodes number, inertia coeffeicent λ, study Rate α, input node number n, output node number q, initializes each layer weighting coefficient w_iI=1,2,3, setting sampling Ordinal number k=1

   (2) carry out sampling and respectively obtain given power-assisted gain R (t) and actual power-assisted gain Q (t), it is E to calculate current time deviation (t) input and output of=R (t)-Q (t) and each layer neuron of BP neural network, the parameter of output is the ratio of PID control, product Point and differential parameter；

   (3) BP neural network progress on-line study is adjusted, to each layer weighting coefficient w_iI=1,2,3 is adaptively adjusted Section；K=k+1 is made, is repeated the above steps (2).