Steering wheel road feel simulation device and road feel simulation method for wire-controlled steering

Abstract

The present invention relates to a steering wheel road feel simulation device for wire-controlled steering, comprising a steering wheel, a motor connected to the steering wheel, an encoder rotating synchronously with the motor, a throttle pedal for acceleration, a brake pedal for deceleration, and a calculation module for controlling the torque output of the motor. Correspondingly, the present invention also provides a method for simulating the road feel of a steering wheel for wire-controlled steering. The steering wheel road feel simulation device for wire-controlled steering provided by the present invention can accurately collect steering wheel angle signals and speed signals in real time, calculate vehicle speed, match different steering wheel torque signals, and realize the simulation of the road feel of the steering wheel for wire-controlled steering, which is authentic and reliable, through the arrangement of a motor, an encoder, a throttle pedal, a brake pedal, and a calculation module.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile accessories, and in particular to a steering wheel road feel simulation device for wire-controlled steering. Accordingly, a method for simulating the road feel of a steering wheel for wire-controlled steering is also provided. Background Art

[0002] The automotive steer-by-wire technology disconnects the traditional mechanical connection between the steering wheel and the steering gear, and controls the movement of the power-assist motor through electrical signals, thereby controlling the rack travel of the steering gear, thus achieving the steering function of the vehicle. The steer-by-wire technology can improve the response speed of the vehicle's steering, eliminate the steering wheel vibration caused by road excitation, and provide a control basis for autonomous driving.

[0003] Since the steer-by-wire disconnects the mechanical connection between the steering wheel and the steering gear, the real road feel of the road cannot be fed back to the driver through the steering wheel, and the steering wheel load torque cannot change with the vehicle speed, steering wheel angle, and steering wheel speed. Therefore, it is necessary to connect a load motor to the steering wheel to simulate the real-time road feel of the car steering wheel.

[0004] However, the existing steering wheel road feel simulation test bench for wire control has the following shortcomings:

[0005] 1. It is impossible to accurately collect the steering wheel angle and speed signals. The system error is large and is only suitable for rough bench simulation. It is impossible to achieve a test drive application level signal system.

[0006] 2. It is impossible to simulate the acceleration and braking process of the car on the test bench. The steps do not have simulation components such as the accelerator pedal, brake pedal, and driver's seat. The wire-controlled steering simulation process is too abstract and there is a big gap between the actual installation and actual vehicle application.

[0007] 3. The existing road feel simulation platform for wire-controlled steering does not provide an installation structure and control method for a road feel simulation motor suitable for installation in a real vehicle, and cannot meet the requirements for bench simulation verification of real vehicle wire-controlled steering. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a steering wheel road feel simulation device for wire-controlled steering, which can accurately collect steering wheel angle signals and speed signals, calculate vehicle speed, match different steering wheel torque sizes, and realize road feel simulation of the steering wheel of wire-controlled steering.

[0009] The technical problem to be solved by the present invention is also to provide a method for simulating the road feel of a steering wheel for steer-by-wire, which realizes the simulation of the road feel of a steering wheel for steer-by-wire, and the simulation process and results are real and reliable.

[0010] In order to solve the above technical problems, the present invention provides a steering wheel road feel simulation device for wire-controlled steering, comprising a steering wheel, a motor connected to the steering wheel, an encoder rotating synchronously with the motor, an accelerator pedal for acceleration, a brake pedal for deceleration, and a calculation module for controlling the torque output of the motor: wherein,

[0011] The calculation module collects the acceleration signal of the accelerator pedal and the deceleration signal of the brake pedal, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal;

[0012] The motor shaft of the steering wheel driving motor rotates, and the motor shaft rotates synchronously with the encoder. The encoder collects the steering wheel angle signal and the speed signal in real time, and feeds the angle signal and the speed signal back to the calculation module;

[0013] The calculation module calculates the torque output signal of the motor according to the steering wheel angle signal, the speed signal and the actual vehicle speed signal, and feeds back the signal to the servo amplifier;

[0014] The servo amplifier controls the motor according to the torque output signal, and the motor acts on the steering wheel.

[0015] Preferably, the steering wheel is connected to the motor via a connecting mechanism, and the connecting mechanism comprises an electrically adjustable column connected to the steering wheel and a coupling connected to the electrically adjustable column.

[0016] Preferably, the electrically adjustable tube column comprises a tube shaft, a core shaft located inside the tube shaft, and a tube column mounting hole located on the tube shaft;

[0017] The steering wheel is sleeved on the core shaft via a spline, and the core shaft is fixedly connected to the motor shaft of the motor via a coupling.

[0018] Preferably, the synchronous rotation between the motor and the encoder is achieved through a synchronous belt set;

[0019] The motor comprises a body and a motor shaft connected to the body;

[0020] The synchronous belt set comprises a driving wheel fixed on the motor shaft, an idler wheel fixed on the encoder, and a synchronous belt.

[0021] Preferably, the motor and the encoder are installed by a motor bracket, wherein:

[0022] The motor bracket is in a U-shaped structure, comprising a bracket body, a motor mounting hole located on the bracket body, an encoder mounting hole located on the bracket body, and a connecting hole located on the bracket body;

[0023] The motor is located inside the motor mounting hole, the encoder is installed inside the encoder mounting hole, and the connecting hole is connected to the tube shaft.

[0024] Preferably, it also includes a fixing mechanism and a seat, wherein the fixing mechanism includes a bottom support frame, a bracket mounted on the bottom support frame, a mounting cover mounted on the bracket, a cover plate mounted on the bottom support frame, a pedal seat mounted on the cover plate, and a seat mounting seat mounted on the bottom support frame;

[0025] The column mounting hole is connected to the mounting cover, and the accelerator pedal and the brake pedal are mounted on the pedal seat.

[0026] Preferably, the bottom support frame comprises a front longitudinal bar, a rear longitudinal bar and a transverse bar connecting adjacent front longitudinal bars or adjacent rear longitudinal bars;

[0027] The cover plate is fixed on the front longitudinal rod, the cover plate is located and fixed on the front longitudinal rod, and the mounting cover is fixed on the cover plate through the bracket;

[0028] The seat mounting seat is fixed on the rear longitudinal rod and can slide along the rear longitudinal rod, and the seat is fixed on the seat mounting seat.

[0029] Preferably, the encoder is an incremental encoder.

[0030] A method for simulating road feel of a steering wheel for steer-by-wire comprises the following steps:

[0031] The calculation module collects the acceleration signal of the accelerator pedal and the deceleration signal of the brake pedal, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal;

[0032] The calculation module receives the steering wheel angle signal and speed signal collected by the encoder;

[0033] The calculation module calculates the torque output signal of the motor according to the steering wheel angle signal, the rotation speed signal and the actual vehicle speed signal, and feeds back the torque output signal to the servo amplifier, and the servo amplifier controls the motor according to the torque output signal.

[0034] Preferably, the method for the calculation module to calculate the torque output signal includes:

[0035] Calculate a basic steering torque signal according to the steering angle signal and the actual vehicle speed signal;

[0036] Calculating a steering damping signal according to a rotation speed signal and an actual vehicle speed signal;

[0037] Calculate the friction signal during the steering process according to the rotation speed signal and the actual vehicle speed signal;

[0038] The sum of the basic steering torque signal, the steering damping signal and the friction signal is the torque output signal T.

[0039] Preferably, the step of the calculation module controlling the motor according to the torque output signal comprises:

[0040] The calculation module converts the torque output signal T into an analog voltage signal u and sends it to the servo amplifier. The servo amplifier transmits the analog voltage signal u to the motor. The motor completes the required torque output under the control of the analog voltage signal u.

[0041] Preferably, the torque output signal T and the analog voltage signal u satisfy:

[0042] T=u / u max *T max , where: T max is the peak torque limit of the motor forward and reverse rotation, u max is the corresponding control voltage peak value.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The steering wheel road feel simulation device for wire-controlled steering provided by the present invention can accurately collect steering wheel angle signals and speed signals in real time, calculate vehicle speed, and match different steering wheel torque signals through the settings of motors, encoders, accelerator pedals, brake pedals and computing modules, thereby realizing the simulation of steering wheel road feel for wire-controlled steering, which is authentic and reliable.

[0045] 2. The method for simulating the road feel of a steering wheel for steer-by-wire provided by the present invention collects acceleration signals, deceleration signals, angle signals and speed signals, calculates the actual vehicle speed based on the collected signals, and matches the corresponding torque output signals, thereby realizing the simulation of the road feel of a steering wheel for steer-by-wire. The simulation process and results are authentic and reliable.

[0046] 3. The steering wheel road feel simulation device for wire-controlled steering provided by the present invention ensures the synchronous rotation of the encoder and the motor through the arrangement of a synchronous belt group and a motor bracket, so that the encoder can obtain the steering wheel angle signal and speed signal in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of a steering wheel road feel simulation device for wire-controlled steering according to the present invention;

[0048] Figure 2 It is a schematic diagram of the principle structure of the steering wheel road feel simulation device for wire-controlled steering of the present invention;

[0049] Figure 3It is a schematic structural diagram of the synchronous rotation of the motor and the encoder of the steering wheel road feel simulation device for wire-controlled steering of the present invention;

[0050] Figure 4 A schematic diagram of the transmission structure of the steering wheel angle and speed of the steering wheel road feel simulation device for steer-by-wire according to the present invention;

[0051] Figure 5 It is a schematic structural diagram of a motor bracket of a steering wheel road feel simulation device for steer-by-wire according to the present invention;

[0052] Figure 6 It is a structural schematic diagram of a fixing mechanism of a steering wheel road feel simulation device for steer-by-wire according to the present invention;

[0053] Figure 7 It is a structural schematic diagram of a mounting cover of a steering wheel road feel simulation device for steer-by-wire according to the present invention;

[0054] Figure 8 It is a flow chart of the method for simulating road feel of a steering wheel for steer-by-wire according to the present invention;

[0055] Fig. 9 The figure is a relationship diagram of the basic steering torque signal and the steering angle signal calculated according to the piecewise function under the simulated working condition of (100 kph, ±25°, 0.2 Hz) of the present invention;

[0056] Fig.10 The simulink model diagram of the steering damping signal under the simulated working conditions of (100kph, ±25°, 0.2Hz);

[0057] Fig.11 is the relationship diagram between the steering damping signal and the steering angle signal;

[0058] Fig.12 This is the relationship diagram between the steering damping signal and the speed signal;

[0059] Fig.13 The simulink model diagram of the friction signal under the simulated working condition of (100kph, ±25°, 0.2Hz);

[0060] Fig.14 This is the relationship diagram between the friction signal and the rotation angle signal;

[0061] Fig.15 This is the relationship diagram of the friction signal changing with the speed signal. DETAILED DESCRIPTION

[0062] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0063] like Figure 1-2 As shown, a steering wheel road feel simulation device for wire-controlled steering includes a steering wheel 1, a motor 2 connected to the steering wheel 1, an encoder 3 rotating synchronously with the motor 2, an accelerator pedal 4 for acceleration, a brake pedal 5 for deceleration, a calculation module 10 for calculating the torque output of the motor 2, and a servo amplifier 20 for controlling the motor 2: wherein,

[0064] The calculation module collects the acceleration signal of the accelerator pedal 4 and the deceleration signal of the brake pedal 5, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal;

[0065] The steering wheel 1 drives the motor shaft of the motor 2 to rotate, and the encoder 3 rotates synchronously with the motor shaft, and collects the angle signal and the speed signal of the steering wheel 1 in real time, and feeds the angle signal and the speed signal back to the calculation module 10;

[0066] The calculation module 10 calculates the torque output signal of the motor 2 according to the steering wheel 1 angle signal, the speed signal and the actual vehicle speed signal, and feeds back to the servo amplifier 20;

[0067] The servo amplifier 20 controls the motor 2 according to the torque output signal, and the motor 2 acts on the steering wheel 1 .

[0068] Specifically, the steering wheel 1 is used to simulate the steering wheel of an actual vehicle, and is connected to the motor 2 to drive the motor shaft of the motor 2 to rotate.

[0069] like Figure 3 As shown, the motor 2 includes a body 21 and a motor shaft 22 connected to the body 21. The motor shaft 22 is connected to the steering wheel 1. Therefore, when the steering wheel 1 rotates, the motor shaft 22 of the motor 2 rotates together, and transmits the steering wheel 1 angle signal and speed signal in real time, and outputs the corresponding torque to act on the steering wheel 1, so as to realize the road feel simulation of the steering wheel 1.

[0070] The accelerator pedal 4 is used to simulate the acceleration process of the car and generate an acceleration signal; the brake pedal 5 is used to simulate the deceleration process of the car and generate a deceleration signal. The computer collects the acceleration signal of the accelerator pedal and the deceleration signal of the brake pedal to calculate the actual vehicle speed signal.

[0071] The calculation module 10 is used to collect the acceleration signal of the accelerator pedal 4 and the deceleration signal of the brake pedal 5, and calculate the actual vehicle speed signal according to the acceleration signal and the deceleration signal;

[0072] At the same time, the steering wheel 1 drives the motor shaft of the motor 2 to rotate, the encoder 3 rotates synchronously with the motor shaft, and collects the steering wheel 1's angle signal and speed signal in real time, and feeds the angle signal and speed signal back to the calculation module 10; the calculation module 10 calculates the torque output signal of the motor 2 according to the steering wheel 1's angle signal, speed signal and actual vehicle speed signal, and feeds it back to the servo amplifier 20. Therefore, the present invention can accurately collect the steering wheel angle signal and speed signal in real time, calculate the vehicle speed, match different steering wheel torque signals, and realize the simulation of the steering wheel road feel of the wire control steering, which is real and reliable.

[0073] As a preferred embodiment of the present invention, the computing module 10 includes an acquisition terminal 101 and a PC terminal 102 (personal computer). The acquisition terminal 101 acquires the acceleration signal of the accelerator pedal 4 and the deceleration signal of the brake pedal 5, wherein the acceleration signal and the deceleration signal are both voltage analog signals. The acquisition terminal 101 converts the acquired voltage analog signals into digital signals and transmits them to the PC terminal 102. The PC terminal 102 is provided with the Dspace Contral Desk software used in conjunction with the acquisition terminal 101, which runs the compiled simulink model online in real time, and calculates and simulates the actual vehicle speed signal based on the digital signal transmitted from the acquisition terminal 101.

[0074] The acquisition terminal 101 may be a device such as AUTOBOX, but is not limited thereto.

[0075] It should be noted that during actual vehicle operation, when the accelerator pedal is working, the brake pedal is not working, so the actual vehicle speed signal is controlled by the accelerator pedal, that is, the actual vehicle speed signal can be obtained only based on the acceleration signal of the accelerator pedal; similarly, when the brake pedal is working, the accelerator pedal is not working, and the actual vehicle speed signal can be obtained only based on the deceleration signal of the brake pedal.

[0076] The following uses the accelerator pedal to simulate the acceleration and deceleration process of an actual car as an example to further explain:

[0077] (I) The accelerator pedal simulates the acceleration process of an actual car, as follows:

[0078] The acquisition end collects the acceleration signal, including the analog voltage signal u", the signal action time △t, and the accelerator pedal angle

[0079] Formula (1):

[0080] Where P is the output power, C1 is the proportional constant, Kv is the proportionality constant.

[0081] Formula (2): F = P / v;

[0082] Among them, F is the vehicle traction, v is the actual vehicle speed signal, and P is the output power.

[0083] Formula (3): F max =f*G*55%;

[0084] Among them, F max is the maximum adhesion of the wheel, f is the ground adhesion coefficient, G is the vehicle weight, and 55% is the load on the front wheel of the device provided by the present invention, which simulates a front-wheel drive car.

[0085] The acceleration process has the following two states:

[0086] State 1: When the vehicle is in a state of force balance: F<F max According to formula (4), the traction force on the car is calculated

[0087] Formula (4): F = F f +F j +F a +F w , where F f is the rolling resistance of the vehicle, F j is the inertial resistance of the vehicle, F a is the slope resistance, F w is the air resistance,

[0088] Formula (5): F f =G*f, where f is the ground adhesion coefficient and G is the vehicle weight;

[0089] Formula (6): F j =C2*Q*a, where C2 is the proportional constant; Q is the equivalent mass of the vehicle; a is the vehicle acceleration;

[0090] Formula (7): F w =1 / 16·A·C w v^2, where A is the cross-sectional area of ​​the car, C w is the drag coefficient, and v is the actual vehicle speed signal.

[0091] In addition, F a is the slope resistance, which is calculated based on the actual road. It is a conventional calculation method and will not be described here;

[0092] Formula (8): The calculation formula of the actual vehicle speed signal is; v = v1 + a*△t, where v1 is the initial vehicle speed, the signal action time △t, and a is the vehicle body acceleration.

[0093] Substitute equations (1), (2), (5), (6), (7) and (8) into equation (4) respectively, and a calculation formula containing a single unknown v can be obtained, so as to obtain the actual vehicle speed signal v.

[0094] State 2: When the traction force is greater than the maximum adhesion of the wheels, the wheels slip and F = Fmax.

[0095] Substitute equations (1) and (3) into equation (2) respectively, and a calculation formula containing a single unknown v can be obtained, so as to obtain the actual vehicle speed signal v.

[0096] Note: Parameter selection is carried out according to the vehicle models to be simulated. There are certain differences in the data of A, B, and C-level sedans and SUV models, and they need to be input separately.

[0097] (2) The brake pedal simulates the deceleration process of an actual vehicle as follows:

[0098] The acquisition end acquires deceleration signals, including the analog voltage signal u’, the signal action time △t’, and the brake pedal rotation angle .

[0099] Formula (1’): a b = T’ / k, where a b is the braking deceleration, T’ is the braking torque, and k is a constant.

[0100] Formula (2’): v’ = v1’ + a b *△t’, where v’ is the actual vehicle speed signal, v1’ is the vehicle speed at the start of braking, and a b is the vehicle body acceleration.

[0101] The deceleration process is divided into three stages:

[0102] Stage 1: When 0 < u’ < u1’, the brake pedal does not brake, that is, the vehicle does not decelerate, v’ = v1’, where u’ is the analog voltage signal, v1’ is the vehicle speed at the start of braking, and u1’ is input according to the calibration value of different brake pedal voltage characteristics.

[0103] Stage 2: When u1’ < u’ < u2’, there is formula (3’): the braking torque T’ = K b1 *(u’ - u1’), where u’ is the analog voltage signal, T’ is the braking torque, and K b1 is the proportional constant input according to the calibration value of different vehicle models, and u1’ is input according to the calibration value of different brake pedal voltage characteristics.

[0104] Substitute equations (1’) and (3’) into equation (2’), and the actual vehicle speed signal v’ at this stage can be obtained.

[0105] Stage 3: When u'>u2', it is the stage of rapid establishment of braking torque T':

[0106] Formula (4'): T' = K b2 *u'^2+K b3 u'+b, where u' is the analog voltage signal, T' is the braking torque, b is a constant, K b2 and K b3 The proportional constant is input according to the calibration value of different vehicle models.

[0107] Substituting equations (1') and (4') into equation (2'), the actual vehicle speed signal v' at this stage can be obtained.

[0108] Among them, K b1 , K b2 , K b3 The proportional constant is input according to the calibration value of different vehicle models, and u1' and u2' are input according to the calibration values ​​of different brake pedal voltage characteristics.

[0109] It should be noted that the braking torque T' should meet the tire adhesion limit, that is When T'>T max When Where G is the vehicle weight, is the brake pedal angle.

[0110] The servo amplifier 20 controls the motor 2 according to the torque output signal, and the motor 2 acts on the steering wheel 1 .

[0111] The structural details of each component are described in detail below:

[0112] like Figure 1 and 4 As shown, the connection between the steering wheel 1 and the motor 2 is achieved through a connecting mechanism 6 , and the connecting mechanism 6 includes an electric adjustment column 61 connected to the steering wheel 1 and a coupling 62 connected to the electric adjustment column.

[0113] Specifically, the electrically adjustable tube column 61 includes a tube shaft 611, a core shaft 612 located inside the tube shaft 611, and a tube column mounting hole 613 located on the tube shaft 611, wherein the tube shaft 611 is used to achieve fixed installation of the electrically adjustable tube column 61, and the core shaft is used to achieve transmission of the steering wheel 1 angle and rotation speed.

[0114] The steering wheel 1 is connected to the core shaft through a spline, and the core shaft is fixedly connected to the motor shaft 22 of the motor 2 through a coupling 62. The spline setting realizes the transmission of the rotation of the steering wheel 1; the setting of the coupling 62 is used to ensure that there is no slippage when the maximum torque of the motor is transmitted.

[0115] The encoder 3 rotates synchronously with the motor 2 to facilitate real-time acquisition of the steering wheel angle signal and speed signal, and feeds the acquired angle signal and speed signal back to the calculation module. It can be an incremental encoder or other encoder that can achieve this function, and is not limited to this embodiment.

[0116] like Figure 3-5 As shown, in this embodiment, the synchronous rotation of the encoder 3 and the motor 2 is achieved through a synchronous belt group 7a, and the motor 2 and the encoder 3 are fixed by a motor bracket 7b, wherein the synchronous belt group 7a includes a driving wheel 71a fixed on the motor shaft 22, an idler wheel 72a fixed on the encoder 3, and a synchronous belt 73a. Therefore, through the action of the synchronous belt group 7a, the synchronous rotation of the encoder 3 and the motor 2 is achieved, which makes it convenient for the encoder 3 to obtain the steering angle signal and the speed signal of the steering wheel 1 in real time, and feed the signal back to the calculation module to realize the road feel simulation of the steering wheel 1.

[0117] The motor bracket 7b has a U-shaped structure, which includes a bracket body 71b, a motor mounting hole 72b located on the bracket body 71b, an encoder mounting hole 73b located on the bracket body 71b, and a connecting hole 74b located on the bracket body 71b. The motor 2 is located inside the motor mounting hole 72b, the encoder 3 is installed inside the encoder mounting hole 73b, and the connecting hole 74b is connected to the pipe axis. The arrangement of the motor bracket 7b is used to ensure that the motor 2 and the encoder 3 can be rotated and adjusted together with the electric adjustment column 61.

[0118] In order to ensure that the motor bracket 7b has sufficient strength to support the motor 2 and the encoder 3, the motor bracket 7b is further provided with a bracket reinforcement rib 75b.

[0119] like Figure 1 and 6 As shown, in order to achieve the simulation of a real car and ensure the authenticity of the simulation process, the steering wheel road feel simulation device for wire-controlled steering of the present invention also includes a fixing mechanism 8 and a seat 9, and the fixing mechanism 8 is used to install the steering wheel 1, the motor 2, the encoder 3, the accelerator pedal 4, the brake pedal 5 and the seat 9.

[0120] Specifically, the fixing mechanism 8 includes a bottom support frame 81, a bracket 82 installed on the bottom support frame 81, a mounting cover 83 installed on the bracket 82, a cover plate 84 installed on the bottom support frame 81, a pedal seat 85 installed on the cover plate 84, and a seat mounting seat 86 installed on the bottom support frame 81, wherein the column mounting hole 613 of the electric adjustment column 61 is connected to the mounting cover 83, and the accelerator pedal 4 and the brake pedal 5 are installed on the pedal seat 85.

[0121] In order to increase the strength of the installation cover 83 , installation cover reinforcement ribs are provided thereon to ensure that it has sufficient strength to be made into the electric adjustment column 61 .

[0122] The bottom support frame 81 includes a front longitudinal bar 811, a rear longitudinal bar 812, and a transverse bar 813 connecting the adjacent front longitudinal bars 811 or the adjacent rear longitudinal bars 812, wherein the cover plate 84 is fixed on the front longitudinal bar 811, the cover plate 84 is located and fixed on the front longitudinal bar 811, and the mounting cover 83 is fixed on the cover plate 84 through the bracket 82. The cover plate 84 is detachably connected to the front longitudinal bar 811, which facilitates the installation and disassembly of the front half of the fixing mechanism 8, and is convenient for installation and transportation.

[0123] The seat mounting seat 86 is fixed on the rear longitudinal rod 812 , wherein the seat mounting seat 86 can slide along the rear longitudinal rod 812 to adjust the position of the seat 9 .

[0124] By providing the front longitudinal rod 811 and the rear longitudinal rod 812 , the front and rear halves of the stand can be detachably installed, which is convenient for transportation and disassembly.

[0125] like Figure 7 As shown, the mounting cover 83 is provided with reinforcing ribs 831, an upper mounting hole 832, a lower mounting hole 833 and a pad 834. The electrically adjustable column 61 is installed through the upper mounting hole 832 and the lower mounting hole 833. Since the mounting position structure on the electrically adjustable column 61 is concave, it is filled with the pad 834. The pad 834 and the mounting cover 83 are welded into an integrated structure.

[0126] The seat 9 is fixed on the seat mounting base 86, and the position of the seat 9 is adjusted by sliding the seat mounting base 86 forward and backward to match the operation of different experimenters and achieve simulation of a real car.

[0127] The steering wheel road feel simulation device for wire-controlled steering provided by the present invention can accurately collect steering wheel angle signals and speed signals in real time, calculate vehicle speed, and match different steering wheel torque signals through the settings of motor 2, encoder 3, accelerator pedal 4, brake pedal 5 and calculation module, thereby realizing the simulation of steering wheel road feel of wire-controlled steering, which is real and reliable.

[0128] Correspondingly, such as Figure 2 and 8 As shown, the present invention also provides a method for simulating road feel of a steering wheel for wire-controlled steering, comprising the following steps:

[0129] The calculation module 10 collects the acceleration signal of the accelerator pedal 4 and the deceleration signal of the brake pedal, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal;

[0130] The calculation module includes a collection terminal 101 and a PC terminal 102 (personal computer). The collection terminal 101 collects the acceleration signal of the accelerator pedal 4 and the deceleration signal of the brake pedal 5, and records the action time of each signal, wherein the acceleration signal and the deceleration signal are both voltage analog signals. The collection terminal 101 converts the collected voltage analog signals into digital signals and transmits them to the PC terminal 102. The PC terminal 102 is equipped with the Dspace Control Desk software used in conjunction with the collection terminal to run the compiled simulink model online in real time, and calculates and simulates the actual vehicle speed signal according to the digital signal transmitted from the collection terminal.

[0131] It should be noted that during actual vehicle operation, when the accelerator pedal is working, the brake pedal is not working, so the actual vehicle speed signal is controlled by the accelerator pedal, that is, the actual vehicle speed signal can be obtained only based on the acceleration signal of the accelerator pedal; similarly, when the brake pedal is working, the accelerator pedal is not working, and the actual vehicle speed signal can be obtained only based on the deceleration signal of the brake pedal.

[0132] The following uses the accelerator pedal to simulate the acceleration and deceleration process of an actual car as an example to further explain:

[0133] (I) The accelerator pedal simulates the acceleration process of an actual car, as follows:

[0134] The acquisition end collects the acceleration signal, including the analog voltage signal u", the signal action time △t, and the accelerator pedal angle

[0135] Formula (1):

[0136] Where P is the output power, C1 is the proportional constant, K v is the proportionality constant.

[0137] Formula (2): F = P / v;

[0138] Among them, F is the vehicle traction, v is the actual vehicle speed signal, and P is the output power.

[0139] Formula (3): F max =f*G*55%;

[0140] Among them, F maxis the maximum adhesion of the wheel, f is the ground adhesion coefficient, G is the vehicle weight, and 55% is the load on the front wheel of the device provided by the present invention, which simulates a front-wheel drive car.

[0141] The acceleration process has the following two states:

[0142] State 1: When the vehicle is in a state of force balance: F<F max According to formula (4), the traction force on the car is calculated

[0143] Formula (4): F = F f +F j +F a +F w , where F f is the rolling resistance of the vehicle, F j is the inertial resistance of the vehicle, F a is the slope resistance, F w is the air resistance,

[0144] Formula (5): F f =G*f, where f is the ground adhesion coefficient and G is the vehicle weight;

[0145] Formula (6): F j =C2*Q*a, where C2 is the proportional constant; Q is the equivalent mass of the vehicle; a is the vehicle acceleration;

[0146] Formula (7): F w =1 / 16·A·C w v^2, where A is the cross-sectional area of ​​the car, C w is the drag coefficient, and v is the actual vehicle speed signal.

[0147] In addition, F a is the slope resistance, which is calculated based on the actual road. It is a conventional calculation method and will not be described here.

[0148] Formula (8): The calculation formula of the actual vehicle speed signal is; v = v1 + a*△t, where v1 is the initial vehicle speed, the signal action time △t, and a is the vehicle body acceleration.

[0149] Substituting equations (1), (2), (5), (6), (7) and (8) into equation (4) respectively, we can obtain the calculation formula containing a single unknown quantity v, thereby obtaining the actual vehicle speed signal v.

[0150] State 2: When the traction force is greater than the maximum adhesion of the wheel, the wheel slips, F=Fmax.

[0151] Substituting equations (1) and (3) into equation (2) respectively, we can obtain a calculation formula containing a single unknown quantity v, thereby obtaining the actual vehicle speed signal v.

[0152] Note: Select parameters according to the vehicle models to be simulated. There are certain differences in the data of A, B, and C-class sedans and SUV models, which need to be input separately.

[0153] (2) The brake pedal simulates the deceleration process of an actual vehicle, specifically as follows:

[0154] The acquisition end acquires deceleration signals, including analog voltage signal u’, signal action time △t’, and brake pedal rotation angle .

[0155] Formula (1’): a b = T’ / k, where a b is the braking deceleration, T’ is the braking torque, and k is a constant.

[0156] Formula (2’): v’ = v1’ + a b *△t’, where v’ is the actual vehicle speed signal, v1’ is the vehicle speed at the start of braking, and a b is the vehicle body acceleration.

[0157] The deceleration process is divided into three stages:

[0158] First stage: When 0 < u’ < u1’, the brake pedal does not brake, that is, the vehicle does not decelerate, v’ = v1’, where u’ is the analog voltage signal, v1’ is the vehicle speed at the start of braking, and u1’ is input according to the calibration value of different brake pedal voltage characteristics.

[0159] Second stage: When u1’ < u’ < u2’, there is formula (3’): braking torque T’ = K b1 *(u’ - u1’), where u’ is the analog voltage signal, T’ is the braking torque, K b1 is the proportional constant input according to the calibration value of different vehicle models, and u1’ is input according to the calibration value of different brake pedal voltage characteristics.

[0160] Substitute formulas (1’) and (3’) into formula (2’), and the actual vehicle speed signal v’ of this stage can be obtained.

[0161] Third stage: When u’ > u2’, it is the stage where the braking torque T’ is quickly established:

[0162] Formula (4’): T’ = K b2 *u’^2 + K b3 u’ + b, where u’ is the analog voltage signal, T’ is the braking torque, b is a constant, and K b2 and K b3 are the proportional constants input according to the calibration value of different vehicle models.

[0163] Substituting equations (1') and (4') into equation (2'), the actual vehicle speed signal v' at this stage can be obtained.

[0164] Among them, K b1 , K b2 , K b3 The proportional constant is input according to the calibration value of different vehicle models, and u1' and u2' are input according to the calibration values ​​of different brake pedal voltage characteristics.

[0165] It should be noted that the braking torque T' should meet the tire adhesion limit, that is When T'>T max When Where G is the vehicle weight, is the brake pedal angle.

[0166] The steering wheel 1 drives the motor shaft of the motor 2 to rotate, and the encoder 3 rotates synchronously with the motor shaft, and collects the angle signal and the speed signal of the steering wheel 1 in real time, and feeds the angle signal and the speed signal back to the calculation module 10;

[0167] The calculation module 10 calculates the torque output signal of the motor 2 according to the steering angle signal, the rotation speed signal and the actual vehicle speed signal of the steering wheel 1 , and feeds back the torque output signal to the servo amplifier 20 .

[0168] Specifically, a basic steering torque signal is calculated according to the steering angle signal and the actual vehicle speed signal;

[0169] Calculating a steering damping signal according to a rotation speed signal and an actual vehicle speed signal;

[0170] Calculate the friction signal during the steering process according to the rotation speed signal and the actual vehicle speed signal;

[0171] The sum of the basic steering torque signal, the steering damping signal and the friction signal is the torque output signal T.

[0172] Among them, the torque output signal T and the analog voltage signal u satisfy the following relationship:

[0173] T=u / u max *T max (Nm), where: T max is the peak torque limit of the motor forward and reverse rotation, u max is the corresponding control voltage peak value, so the analog voltage signal u can be calculated according to the torque output signal T. The motor completes the required torque output under the control of the analog voltage signal u, thereby realizing the simulation of the steering wheel road feel.

[0174] The following simulates the specific calculation process with a simulated vehicle speed of 100km / h, a ±25° steering angle signal and a 0.2Hz speed signal:

[0175] 1) Basic steering torque signal:

[0176] The torque of the steering wheel road feel simulation is mainly provided by the basic steering torque signal.

[0177] like Fig. 9 As shown, under the simulated working condition of (100kph, ±25°, 0.2Hz), the relationship between the basic steering torque signal and the steering angle signal calculated by the piecewise function is shown.

[0178] 2) Steering damping signal:

[0179] like Fig.10 The simulink model diagram of the steering damping signal under the simulated working condition of (100kph, ±25°, 0.2Hz). The steering damping signal is related to the steering angle signal and the speed signal, such as Figure 11-12 As shown in FIG. 1 , the steering damping signal decreases as the angle signal increases, but increases as the speed signal increases. In addition, the steering damping signal needs to look up the table according to the torque target to obtain the damping gain, which is multiplied by the original damping to obtain the final output.

[0180] 3) Friction signal:

[0181] like Fig.13 The following is the simulink model diagram of the friction signal under the simulated working condition of (100kph, ±25°, 0.2Hz). According to the speed signal input, the LuGre friction force is calculated as the friction signal simulation quantity. It is also necessary to look up the friction simulation gain according to the torque target, multiply it by the friction simulation quantity, and get the final output.

[0182] Fig.14 This is the relationship diagram between the friction signal and the rotation angle signal; Fig.15 This is the relationship diagram of the friction signal changing with the speed signal.

[0183] Finally, the torque output signal T is the sum of the basic steering torque signal, the steering damping signal and the friction signal.

[0184] According to the formula T = u / u max *T max (Nm) Calculate the analog voltage signal u, where: T max is the peak torque limit of the motor forward and reverse rotation, u max is the corresponding control voltage peak value.

[0185] The motor completes the required torque output under the control of the analog voltage signal u, thereby simulating the steering wheel road feel.

[0186] The analog voltage corresponding to the torque target is calculated and sent to the motor, thereby controlling the output torque of the motor.

[0187] The servo amplifier 20 controls the motor 2 according to the torque output signal, and the motor 2 acts on the steering wheel 1 .

[0188] The simulation method of the steering wheel road feel simulation device for wire-controlled steering provided by the present invention realizes the simulation of the steering wheel road feel of wire-controlled steering by collecting acceleration signals, deceleration signals, angle signals and speed signals, and calculating the actual vehicle speed signal based on the collected signals and matching the corresponding torque output signals. The simulation process and results are true and reliable.

[0189] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for simulating road feel of a steering wheel for steer-by-wire, characterized in that: The following steps are involved: The calculation module collects the acceleration signal of the accelerator pedal and the deceleration signal of the brake pedal, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal; The calculation module receives the steering wheel angle signal and speed signal collected by the encoder; The calculation module calculates the torque output signal of the motor according to the steering wheel angle signal, the speed signal and the actual vehicle speed signal, and feeds back the signal to the servo amplifier, and the servo amplifier controls the motor according to the torque output signal; The method for calculating the torque output signal by the calculation module includes: calculating a basic steering torque signal according to the rotation angle signal and the actual vehicle speed signal; calculating a steering damping signal according to the rotation speed signal and the actual vehicle speed signal; calculating a friction signal during the steering process according to the rotation speed signal and the actual vehicle speed signal; the sum of the basic steering torque signal, the steering damping signal and the friction signal is the torque output signal T; The step of the calculation module controlling the motor according to the torque output signal includes: the calculation module converts the torque output signal T into an analog voltage signal u and sends it to the servo amplifier, the servo amplifier transmits the analog voltage signal u to the motor, and the motor completes the required torque output under the control of the analog voltage signal u; the torque output signal T and the analog voltage signal u satisfy: T=u / u max *T max , where: T max is the peak torque limit of the motor forward and reverse rotation, u max is the corresponding control voltage peak value.

2. A steering wheel road feel simulation device for steer-by-wire based on the method for simulating the road feel of a steering wheel for steer-by-wire according to claim 1, characterized in that: The system comprises a steering wheel, a motor connected to the steering wheel, an encoder rotating synchronously with the motor, an accelerator pedal for acceleration, a brake pedal for deceleration, and a calculation module for controlling the torque output of the motor: wherein, The calculation module collects the acceleration signal of the accelerator pedal and the deceleration signal of the brake pedal, and calculates the actual vehicle speed signal according to the acceleration signal and the deceleration signal; The motor shaft of the steering wheel driving motor rotates, and the motor shaft rotates synchronously with the encoder. The encoder collects the steering wheel angle signal and the speed signal in real time, and feeds the angle signal and the speed signal back to the calculation module; The calculation module calculates the torque output signal of the motor according to the steering wheel angle signal, the speed signal and the actual vehicle speed signal, and feeds back the signal to the servo amplifier; The servo amplifier controls the motor according to the torque output signal, and the motor acts on the steering wheel.

3. The steering wheel road feel simulation device for steer-by-wire according to claim 2, characterized in that: The steering wheel is connected to the motor via a connecting mechanism, and the connecting mechanism comprises an electric adjustment column connected to the steering wheel and a coupling connected to the electric adjustment column.

4. The steering wheel road feel simulation device for steer-by-wire according to claim 3, characterized in that: The electric adjustment pipe column includes a pipe shaft, a core shaft located inside the pipe shaft, and a pipe column installation hole located on the pipe shaft; The steering wheel is sleeved on the core shaft via a spline, and the core shaft is fixedly connected to the motor shaft of the motor via a coupling.

5. The steering wheel road feel simulation device for steer-by-wire according to claim 2, characterized in that: A synchronous belt group is used to realize the synchronous rotation between the motor and the encoder; The motor comprises a body and a motor shaft connected to the body; The synchronous belt set comprises a driving wheel fixed on the motor shaft, an idler wheel fixed on the encoder, and a synchronous belt.

6. The steering wheel road feel simulation device for steer-by-wire according to claim 4, characterized in that: The motor and the encoder are installed by a motor bracket, wherein: The motor bracket is in a U-shaped structure, comprising a bracket body, a motor mounting hole located on the bracket body, an encoder mounting hole located on the bracket body, and a connecting hole located on the bracket body; The motor is located inside the motor mounting hole, the encoder is installed inside the encoder mounting hole, and the connecting hole is connected to the tube shaft.

7. The steering wheel road feel simulation device for steer-by-wire according to claim 4, characterized in that: It also includes a fixing mechanism and a seat, wherein the fixing mechanism includes a bottom support frame, a bracket mounted on the bottom support frame, a mounting cover mounted on the bracket, a cover plate mounted on the bottom support frame, a pedal seat mounted on the cover plate, and a seat mounting seat mounted on the bottom support frame; The column mounting hole is connected to the mounting cover, and the accelerator pedal and the brake pedal are mounted on the pedal seat.

8. The steering wheel road feel simulation device for steer-by-wire according to claim 7, characterized in that: The bottom support frame includes a front longitudinal rod, a rear longitudinal rod, and a transverse rod connecting adjacent front longitudinal rods or adjacent rear longitudinal rods; The cover plate is fixed on the front longitudinal rod, and the mounting cover is fixed on the cover plate through the bracket; The seat mounting seat is fixed on the rear longitudinal rod and can slide along the rear longitudinal rod, and the seat is fixed on the seat mounting seat.

9. The steering wheel road feel simulation device for steer-by-wire according to claim 2, characterized in that: The encoder is an incremental encoder.

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