Distributed motor differential control device and automobile

Abstract

The utility model relates to a distributed motor differential control device and an automobile. The control device comprises a first motor, a second motor and two first rotating speed rheostats, wherein the first motor and the second motor drive the first wheel and the second wheel to rotate respectively, and the two first rotating speed rheostats are correspondingly connected with the first motor and the second motor respectively. The first rotating speed rheostat comprises an inner side slide piece area corresponding to an inner side wheel and an outer side slide piece area corresponding to an outer side wheel, and the curve shapes of the inner side slide piece area and the outer side slide piece area are determined according to the Akammann formula. The steering mechanism is connected with and drives the first rotating speed rheostat to adjust the output resistance value according to the steering angle and output a speed regulation control signal according to the resistance value. The first motor and the second motor adjust the rotating speed according to the speed regulation control voltage signal of the first rotating speed rheostat connected with the first motor and the second motor. According to the utility model, real-time, efficient and reliable differential control can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile differential speed control, in particular to a distributed motor differential speed control device and an automobile. Background Art

[0002] New energy vehicles can achieve enhanced functions by using distributed motors. The current technical solutions face a difficult problem to solve: the power distribution of distributed motors under turns or complex road conditions. Traditional differentials fail. Currently, intelligent program control is generally used. The system is complex, costly, and has reliability issues. Traditional differentials are not suitable for distributed motor scenarios. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a distributed motor differential speed control device and a vehicle.

[0004] The utility model solves the technical problem by adopting the following technical solution: a distributed motor differential speed control device, used for steering control of a vehicle, wherein the vehicle comprises a first wheel, a second wheel, and a steering mechanism for driving the first wheel and the second wheel to steer, and the distributed motor differential speed control device comprises a first motor and a second motor for driving the first wheel and the second wheel to rotate respectively, and two first speed rheostats respectively connected to the first motor and the second motor;

[0005] The first speed rheostat comprises an inner sliding vane area corresponding to the inner wheel and an outer sliding vane area corresponding to the outer wheel, wherein the curve shapes of the inner sliding vane area and the outer sliding vane area are determined according to the Ackerman formula;

[0006] The steering mechanism is connected to and drives the first speed rheostat to adjust the output resistance value according to the steering angle and output a speed control signal according to the resistance value;

[0007] The first motor and the second motor adjust their rotation speeds respectively according to the speed control signal of the first rotation speed rheostat connected thereto.

[0008] In some embodiments, the first speed rheostat includes a linear resistor / coil and a contact slider;

[0009] One end of the initial position of the resistor / coil is fixed at the rotation center, and the other end is initially located at a polar angle of 0. The maximum effective variable resistance area length R max ≥ Maximum pole diameter, the rotation center end is connected to the negative pole of the power supply, and the other end of the resistor / coil is connected to the positive pole of the power supply;

[0010] If the contact slide is fixed, the resistor / coil rotates synchronously with the steering mechanism; or, if the resistor / coil is fixed, the contact slide rotates synchronously with the steering mechanism in the opposite direction.

[0011] In some embodiments, the curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the polar coordinate equation (I) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the polar coordinate equation (II) or its equivalent equation;

[0012] The polar coordinate equation (I) is: R1 = R0*f(α);

[0013] The polar coordinate equation (II) is: R2 = R0*g(β);

[0014] in, c=a / b, a is the wheelbase of the left and right wheels on the same horizontal line, b is the wheelbase of the front and rear wheels on the same horizontal line, α is the inner steering angle when the car turns, β is the outer steering angle when the car turns, and R0 is the maximum effective length of the resistor / coil of the speed rheostat; or

[0015] The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the polar coordinate equation (III) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the polar coordinate equation (IV) or its equivalent equation;

[0016] The polar coordinate equation (III) is: R1 = R0 / f(α);

[0017] The polar coordinate equation (IV) is: R2 = R0 / g(β);

[0018] At this time, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor.

[0019] In some embodiments, the distributed motor differential speed control device further includes a second speed rheostat, which is connected in series with the first speed rheostat to reduce system errors, and the first motor and the second motor respectively adjust their speeds according to the voltage difference between corresponding contacts of the first speed rheostat and the second speed rheostat connected thereto;

[0020] Among them, the curve shape of the inner sliding area of ​​the first speed rheostat satisfies the polar coordinate equation (1), and the curve shape of the outer sliding area of ​​the first speed rheostat satisfies the polar coordinate equation (2); the curve shape of the inner sliding area of ​​the second speed rheostat satisfies the polar coordinate equation (3), and the curve shape of the outer sliding area of ​​the second speed rheostat satisfies the polar coordinate equation (4).

[0021] In some embodiments, the distributed motor differential control device further comprises a power supply, wherein the positive pole of the power supply is connected to the outer vane end of the first speed rheostat connected to the first motor and the inner vane end of the first speed rheostat connected to the second motor, and the negative pole of the power supply is connected to the inner vane end of the first speed rheostat connected to the first motor and the outer vane end of the first speed rheostat connected to the second motor; or

[0022] The speed control signal includes a speed voltage control signal or a speed current control signal output according to the resistance value conversion; the first motor and the second motor adjust their speeds according to the corresponding speed voltage control signal or speed current control signal.

[0023] In some embodiments, the curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the rectangular coordinate equation (5) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the rectangular coordinate equation (6) or its equivalent equation;

[0024] The rectangular coordinate equation (V) is: Y1 = R0*f(α), X1 = D0*α;

[0025] The rectangular coordinate equation (VI) is: Y2 = R0*g(β), X2 = -D0*β;

[0026] Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the ratio of the circumference of a circle to the radius of the circle; D0 is the radius of the unfolded circle, which is equivalent to the pitch radius of the steering gear; the maximum turning angle of the outer area is less than 90 degrees; R0 is the maximum effective length of the resistor / coil; or

[0027] The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the rectangular coordinate equation (VII) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the rectangular coordinate equation (VIII) or its equivalent equation;

[0028] The rectangular coordinate equation (VII) is: Y1 = R0 / f(α), X1 = D0*α;

[0029] The rectangular coordinate equation (VIII) is: Y2=R0 / g(β), X2=-D0*β;

[0030] At this time, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor.

[0031] In some embodiments, the automobile further includes a third wheel and a fourth wheel, the steering mechanism drives the third wheel and the fourth wheel to rotate, and the distributed motor differential control device further includes a third motor and a fourth motor respectively driving the third wheel and the fourth wheel to rotate, and two third speed rheostats respectively connected to the third motor and the fourth motor;

[0032] The curve shape of the inner sliding plate area of ​​the third speed rheostat satisfies the rectangular coordinate equation (I) or its equivalent equation, and the curve shape of the outer sliding plate area satisfies the rectangular coordinate equation (II) or its equivalent equation;

[0033] The rectangular coordinate equation (I) is: Y3 = R0*cos(α)*f(α), X3 = D0*α;

[0034] The rectangular coordinate equation (II) is: Y4 = R0*cos(β)*g(β), X4 = -D0*β;

[0035] Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the circumference of a circle; the maximum angle of the outer side satisfies ctg(β)=c; D0 is the radius of the unfolded circle, which is equivalent to the pitch radius of the steering gear; or

[0036] The curve shape of the inner sliding plate area of ​​the third speed rheostat satisfies the rectangular coordinate equation (three) or its equivalent equation, and the curve shape of the outer sliding plate area satisfies the rectangular coordinate equation (four) or its equivalent equation;

[0037] The rectangular coordinate equation (III) is:

[0038]

[0039] The rectangular coordinate equation (IV) is:

[0040]

[0041] At this time, the output resistance values ​​of the two third speed rheostats cross-control the third motor and the fourth motor.

[0042] In some embodiments, the distributed motor differential speed control device further includes a fourth speed rheostat, which is connected in series with the third speed rheostat to reduce system errors, and the third motor and the fourth motor respectively adjust their speeds according to the voltage difference output by the corresponding contacts of the third speed rheostat and the fourth speed rheostat connected thereto;

[0043] Among them, the curve shape of the inner sliding area of ​​the third speed rheostat satisfies the rectangular coordinate equation (one), and the curve shape of the outer sliding area of ​​the third speed rheostat satisfies the rectangular coordinate equation (two); the curve shape of the inner sliding area of ​​the fourth speed rheostat satisfies the rectangular coordinate equation (three), and the curve shape of the outer sliding area of ​​the fourth speed rheostat satisfies the rectangular coordinate equation (four).

[0044] In some embodiments, in a four-wheel turning mode of a four-motor vehicle model, the control device further comprises two four-wheel resistors respectively connected in parallel with the first speed resistor;

[0045] The equation satisfied by the curve shape of the inner and outer sliding vane areas of the four-wheel rheostat is the same as that of the first speed rheostat, and at this time, the parameter c=a / 2b.

[0046] In addition, the utility model also provides a car, including the distributed motor differential control device as described above.

[0047] The distributed motor differential control device and automobile implementing the utility model have the following beneficial effects: the utility model utilizes the curve equation that meets the needs to construct a control rheostat, adjusts the resistance value by different steering angles, and automatically obtains the corresponding motor speed control signal when turning, which can realize real-time, efficient and reliable differential control. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0049] Figure 1 This is a schematic diagram of the relationship between the turning radii of the front wheels of a car provided by the utility model;

[0050] Figure 2 It is a schematic diagram of the slider shape of the front wheel rheostat using f,g based on the polar coordinate equation of some embodiments of the utility model;

[0051] Figure 3 is a schematic diagram of the shape of the slider of the front wheel rheostat using 1 / f, 1 / g based on the polar coordinate equation of some embodiments of the utility model;

[0052] Figure 4 It is a schematic diagram of the shape of the slider using f, g based on the rectangular coordinate equation of the front wheel speed rheostat of some embodiments of the utility model;

[0053] Figure 5 It is a schematic diagram of the shape of the slider of the front wheel speed rheostat using 1 / f, 1 / g based on the rectangular coordinate equation of some embodiments of the utility model;

[0054] Figure 6 is a schematic diagram of the shape of the slider using f, g based on the polar coordinate equation for the rear wheel speed rheostat of some embodiments of the utility model;

[0055] Figure 7 is a schematic diagram of the shape of the slider of the rear wheel speed rheostat using 1 / f, 1 / g based on the polar coordinate equation in some embodiments of the utility model;

[0056] Figure 8is a schematic diagram of the shape of the slider using f, g based on the rectangular coordinate equation of the rear wheel speed rheostat of some embodiments of the utility model;

[0057] Fig. 9 is a schematic diagram of the shape of the slider of the rear wheel speed rheostat using 1 / f, 1 / g based on the rectangular coordinate equation of some embodiments of the utility model;

[0058] Fig.10 This is a schematic diagram of the relationship between the turning radii of the four wheels of a car provided by the utility model;

[0059] Fig.11 is a schematic diagram of a differential control voltage signal circuit of some embodiments of the utility model;

[0060] Fig.12 Schematic diagram of error reduction circuits in some embodiments of the utility model. DETAILED DESCRIPTION

[0061] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0062] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0063] It should be noted that when an element is described as being "fixed to" another element, it may be directly on the other element, or one or more centered elements may exist therebetween. When an element is described as being "connected to" another element, it may be directly connected to the other element, or one or more centered elements may exist therebetween. When the terms "vertical", "horizontal", "left", "right", "upper", "lower", "inner", "outer", "bottom" and the like are used to indicate an orientation or positional relationship, it is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0064] It should be understood that although the words "first", "second" and the like may be used to limit components in the embodiments of the present utility model, this is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of the present application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0066] In one of the embodiments disclosed in the present utility model, the distributed motor differential control device of this embodiment is used for automobile steering control. The automobile includes a first wheel, a second wheel, and a steering mechanism that drives the first wheel and the second wheel to steer. The distributed motor differential control device of this embodiment includes a first motor and a second motor that respectively drive the first wheel and the second wheel, and two first speed resistors that are respectively connected to the first motor and the second motor.

[0067] The first speed rheostat includes an inner sliding plate area corresponding to the inner wheel and an outer sliding plate area corresponding to the outer wheel, wherein the curve shapes of the inner sliding plate area and the outer sliding plate area are determined according to the Ackerman formula. The steering mechanism is connected to and drives the first speed rheostat to adjust the output resistance according to the steering angle of the vehicle, and converts the resistance into a speed control signal of the corresponding motor. The first motor and the second motor adjust their speeds respectively according to the speed control voltage signal corresponding to the first speed rheostat connected thereto.

[0068] Specifically, the steering mechanism drives the first speed rheostat to adjust the effective differential resistance of the access circuit according to the turning angle of the car, and converts the effective differential resistance into a speed regulating voltage control signal or a speed regulating current control signal of the corresponding motor according to the resistance voltage division principle. The following mainly describes the working principle of this solution based on voltage control.

[0069] In this embodiment, a variable resistor for controlling the motor speed is constructed by using a curve equation that meets the requirements, and the resistance value is adjusted by different steering angles, so that the corresponding motor speed regulation voltage signal is automatically obtained when turning, realizing real-time, efficient and reliable differential control. It can effectively solve the problem of dual-motor models and four-motor models.

[0070] The following embodiments mainly take the first wheel as the left front wheel, the second wheel as the right front wheel, the first motor as the left front wheel motor, the second motor as the right front wheel motor, the third wheel as the left rear wheel, the fourth wheel as the right rear wheel, the third motor as the left rear wheel motor, and the fourth motor as the right rear wheel motor as an example to further explain the technical solution in detail.

[0071] like Figure 1The figure shows the relationship analysis of the turning radius when the front wheels of a car turn. In a left turn, the inner steering angle is α, the outer steering angle is β, the left front wheel turning radius is r1, the right front wheel turning radius is r2, the four wheels are in pure rolling, and the overall turning angle of the car body is δ. The moving arc lengths of each wheel are r1δ, r2δ, r3δ, and r4δ respectively. Assuming that the radius of the four wheels is equal, the speed ratio of the left front wheel and the right front wheel is: ω1 / ω2=r1δ / r2δ=r1 / r2. The transmission ratio of the distributed motor and the wheel is consistent, so it is obvious that the speed ratio of the left front wheel motor and the right front wheel motor is also equal to ω1 / ω2. Assuming that the motor speed control signal is the control voltage value U (the subscripts 1, 2, 3, and 4 correspond to the inner front wheel, outer front wheel, inner rear wheel, and outer rear wheel respectively throughout the text), and is proportional to the speed, that is, U1 / U2=ω1 / ω2. According to the Ackerman formula, ctg(β)=ctg(α)+c; where c=a / b, a is the wheelbase of the left and right wheels on the same horizontal line, and b is the wheelbase of the front and rear wheels on the same horizontal line. It is easy to get:

[0072] The inner steering angle is used as a parameter;

[0073] The outer steering angle is used as a parameter;

[0074] Therefore, the steering signal needs to be converted into a voltage signal. According to the principle of resistor voltage division, the steering signal can be converted into a resistance change to obtain the corresponding voltage signal. To meet the corresponding voltage ratio relationship, it needs to be converted into a resistance ratio relationship. Resistance is proportional to length, so the angle is converted into a change in polar diameter through the polar coordinate equation to obtain the correct voltage ratio.

[0075] Assuming that the resistance is proportional to the polar diameter, the polar coordinate equation of the inner wheel steering resistance is:

[0076] R1=R0*f(α), which is the polar coordinate equation (I); then U1=U0*f(α); where U0 is the control voltage during forward driving.

[0077] Assume that the polar coordinate equation of the steering resistance of the outer wheel is:

[0078] R2=R0*g(β), which is the polar coordinate equation (II); then U2=U0*g(β);

[0079]

[0080] Easy to launch:

[0081]

[0082] When ctg(α)+c=ctg(β), it is easy to know that f=1 / g;

[0083] therefore, Meet design needs.

[0084] In another embodiment, since f and g are inversely related to each other when the Ackerman relationship is satisfied, it is obvious that the voltage ratio can also be obtained by using R1=R0 / f (polar coordinate equation (three)) and R2=R0 / g (polar coordinate equation (four)). In this embodiment, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor. In other words, the left wheel rheostat voltage controls the speed of the right wheel motor, and the right wheel rheostat voltage controls the speed of the left wheel motor. That is, U1=U0 / g, U2=U0 / f, at this time U1 / U2=f / g, and the voltage ratio effect is the same. Optionally, if the measurement signal voltage is fixed and the current is used as the signal, the current is inversely proportional to the resistance. Obviously, the current can also be used to control the motor speed.

[0085] In some embodiments, the resistance of the speed rheostat is proportional to the pole diameter. Specifically, the speed rheostat mainly consists of two parts:

[0086] Resistor: Use a linear resistor, such as a resistor sheet or coil. Initially, one end is always fixed at the center of rotation, and the other end is initially located at a polar angle of 0. The maximum effective variable resistance area length R is required. max Greater than or equal to the maximum polar diameter.

[0087] Contact slider part: the left half of the slider (i.e. the inner slider area) satisfies the curve R1 = R0*f(α), and the right half of the slider (i.e. the outer slider area) satisfies the curve R2 = R0*g(β);

[0088] Optionally, the slider can be fixedly arranged, or the linear resistor can be fixedly arranged. When the fixed contact slider method is adopted, the resistor / coil rotates synchronously with the wheel steering (or steering mechanism). When the fixed resistor / coil method is adopted, the contact slider rotates synchronously with the wheel steering (or steering mechanism) in the opposite direction.

[0089] Working voltage U max Applied across the resistor / coil, it is obvious that the forward driving control voltage U0 = U max *R0 / R max The positive pole of the power supply is connected to the upper end, the negative pole is connected to the rotating center end, and the voltage signal takes the voltage difference from the metal conductive slider end to the negative pole.

[0090] like Figure 2 As shown, this is a schematic diagram of the slider shape of the front wheel speed resistor using f,g. In this scheme, the voltage control signal does not require cross control.

[0091] like Figure 3 As shown, it is a schematic diagram of the front wheel speed rheostat using a 1 / f, 1 / g slider shape. In this scheme, the voltage control signal requires cross control.

[0092] In this embodiment, the above sliders are all given polar coordinate curves with the resistor rotation angle equal to the wheel rotation angle. If the resistor rotation angle is n times the wheel rotation angle, it is only necessary to change the polar angle in the curve equation to 1 / n, that is, the polar angle in the curve equation is always equal to the wheel rotation angle, that is, the inner slider curve is R1 = R0*f(α / n); the outer slider curve is R2 = R0*g(β / n), which is the corresponding equivalent equation. The same reason will not be repeated in the following text.

[0093] In some embodiments, in addition to the polar coordinate curve, the curve can also be expanded into a rectangular coordinate parametric equation in a linear manner in polar angles. The variable resistor structure can achieve the same variable resistance effect by means of gears driving racks, and its production and manufacturing are simpler. The disadvantage is that for electrical appliances, the rack activity space is not compact enough and reliability will be reduced.

[0094] Specifically, the curve shape of the inner sliding area of ​​the first speed rheostat satisfies the rectangular coordinate equation (5) or its equivalent equation, and the curve shape of the outer sliding area satisfies the rectangular coordinate equation (6) or its equivalent equation. There are also two schemes of non-cross control and cross control.

[0095] Combination Figure 4 , is a schematic diagram of the slider shape using f, g when the first speed rheostat adopts the rectangular coordinate equation, and the non-crossing parameter equation is as follows:

[0096] Medial area: Y1=R0*f(α), X1=D0*α.

[0097] Outer region: Y2=R0*g(β), X2=-D0*β.

[0098] Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the ratio of the circle to the circumference of the circle. D0 is the radius of the unfolded circle, which is equivalent to the pitch radius of the steering gear. The maximum turning angle of the outer area is less than 90 degrees. R0 is the maximum effective length of the resistor / coil.

[0099] It should be noted that the steering gear rotation angle is assumed to be 1:1 with the wheel steering angle; if it is not 1:1, but n:1, that is, the wheel steering angle is α, the gear rotation is nα, then D0 needs to be adjusted to D0 / n. This article uses n=1 to illustrate the solution. The rheostat needs to be marked with parameters R0 and D0 for easy assembly.

[0100] Combination Figure 5 , is a schematic diagram of the shape of the slider using 1 / f, 1 / g when the first speed rheostat adopts the rectangular coordinate equation. The cross parameter equation is as follows:

[0101] Medial area: Y1=R0 / f(α), X1=D0*α.

[0102] Outer region: Y2=R0 / g(β), X2=-D0*β.

[0103] Due to cross control, that is, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor, U1 corresponds to Y2, that is, U1=U0 / g; U2=U0 / f; then U1 / U2=f / g meets the requirements.

[0104] In some embodiments, the steering mechanism also drives the third wheel and the fourth wheel to rotate, and the distributed motor differential control device also includes a third motor and a fourth motor that respectively drive the third wheel and the fourth wheel to rotate, and two third speed resistors respectively connected to the third motor and the fourth motor.

[0105] For four-motor models, r3 / r1=cos(α), r4 / r2=cos(β); that is, U3=U1*cos(α), U4=U2*cos(β);

[0106] refer to Figure 6 , is a schematic diagram of the slider shape of the rear wheel resistor based on the polar coordinate equation using f, g, non-crossing scheme: U3 = U0*cos(α)*f(α); U4 = U0*cos(β)*g(β);

[0107] That is, R3 = R0*cos(α)*f(α); R4 = R0*cos(β)*g(β); Obviously, the resistance is 0 at 90 degrees. To avoid signal failure, a breakpoint needs to be set near 90 degrees so that the breakpoint of the slider does not contact the resistor within the effective turning range.

[0108] Combination Figure 7 , for the rear wheel rheostat based on polar coordinate equations using 1 / f, 1 / g of the slider shape diagram, for the crossover scheme:

[0109] at this time,

[0110] and

[0111] That is, there is an outer slide:

[0112]

[0113] Similarly,

[0114]

[0115] That is, there is an inner slide:

[0116]

[0117] In the crossover mode, the outer region R3 is 0 when ctg(β)=c, and a breakpoint needs to be set to prevent the wiper voltage from always being 0.

[0118] The cosine function relationship can be used in many ways. This solution uses a consistent curve solution. The solution that depends on the front wheel also has two types of cross control or not. The same method can also be used. For example, if R = R0*f(α), the curve h = cos(α)*f(α) is also used. R = R0*h is used to control the rear wheels at the same time.

[0119] Obviously, because the cosine value is 0 when the inner steering angle is 90 degrees, that is, r3 = 0, the inner rear wheel does not move, and the vehicle body rotates around the inner rear wheel. Directly using the polar coordinate curve slider will lead to a limited maximum steering angle. To overcome this problem, it is recommended to use a straight coordinate parametric equation for rear wheel control, which can solve this problem. Parametric equations also have two solutions: crossed and non-crossed.

[0120] like Figure 8 As shown, it is a schematic diagram of the shape of the slider of the rear wheel rheostat (third speed rheostat) based on the rectangular coordinate equation using f, g, and the non-crossing parameter equation is as follows:

[0121] Inner area: Y3 = R0*cos(α)*f(α); X3 = D0*α. That is, the rectangular coordinate equation (I).

[0122] Outer area: Y4 = R0*cos(β)*g(β); X4 = -D0*β. This is the rectangular coordinate equation (II).

[0123] Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the circumference of a circle. The maximum angle of the outer side satisfies ctg(β)=c. D0 is the radius of the development circle, which is equivalent to the pitch circle radius of the steering gear.

[0124] like Fig. 9 As shown, it is a schematic diagram of the slider shape of the rear wheel resistor based on the rectangular coordinate equation using 1 / f, 1 / g. The cross parameter equation is as follows:

[0125] Medial area:

[0126]

[0127] X3=D0*α;Obviously, U4=U0*cos(β) / f(α)=U2*cos(β). This is the rectangular coordinate equation (III).

[0128] Outer area:

[0129]

[0130] X4=-D0*β;Obviously, U3=U0*cos(α) / g(β)=U1*cos(α). This is the rectangular coordinate equation (IV).

[0131] Because when ctg(β)≤c, Y4<=0, in order to avoid negative values ​​and facilitate manufacturing and control, Y4 is translated in the positive direction, and the resistor is translated synchronously at the same time to keep the effective resistance value unchanged.

[0132] When the inner and outer sliding areas of the rear wheel speed rheostat adopt corresponding cross-parameter equations (the rheostat constructed according to the cross-parameter equation is called a cross-rheostat), the output resistance values ​​of the two third speed rheostats cross-control the third motor and the fourth motor, that is, the left wheel motor is controlled by the right resistor, and the right wheel motor is controlled by the left resistor.

[0133] In this embodiment, a rear wheel rheostat that controls the motor speed is constructed using a curve equation that meets the requirements. The resistance value is adjusted by different steering angles, so that the corresponding motor speed regulation voltage signal is automatically obtained when turning, and real-time, efficient and reliable differential control can be achieved for four-motor vehicles.

[0134] like Fig.10 As shown, it is a schematic diagram of the relationship between the turning radii of four-wheel turning. In four-wheel turning, due to symmetry, r1=r3, r2=r4. Compared with two-wheel turning, the rotation center is moved from the rear wheel axle to the center line of the front and rear axles. Therefore, only one set of front wheel differential resistors needs to be added. The control equation is the same. It is only necessary to change the parameter c=a / b to 2c=2a / b. It is named as a four-wheel rheostat. When switching the mode, U3=U1, U4=U2, that is, switching the signal voltage source, which will not be repeated.

[0135] like Fig.11 As shown, it is a schematic diagram of the differential control voltage signal circuit. In this embodiment, the distributed motor differential control device also includes a power supply, and two first speed rheostats are arranged in parallel and connected to the power supply. That is to say, when the power supply is shared, the speed rheostats between the left and right wheels are arranged in parallel. Therefore, the two third speed rheostats of the rear wheel are also arranged in parallel.

[0136] Specifically, the positive pole of the power supply is connected to the outer slider end of the first speed rheostat connected to the first motor and the inner slider end of the first speed rheostat connected to the second motor, and the negative pole of the power supply is connected to the inner slider end of the first speed rheostat connected to the first motor and the outer slider end of the first speed rheostat connected to the second motor. Fig.11 In the protection resistor R 10 Connected in series with the speed rheostat, the power supply working voltage is V, and the maximum resistance of the differential resistor is R max , effective differential resistance R(α); motor speed control signal voltage U:

[0137]

[0138] In this embodiment, increasing the operating voltage V can effectively improve the sensitivity, but will increase power consumption.

[0139] The left and right front wheels use the same front wheel resistor; the left and right rear wheels use the same rear wheel resistor;

[0140] Understandably, in the four-wheel turning mode, the left and right front wheels need to be equipped with the same four-wheel rheostat; because it is circuit controlled, only a common power supply is needed and the rheostat is connected in parallel. For dual-motor front-wheel drive models, only two front-wheel rheostats are needed in parallel. For four-motor four-wheel drive models, there are two situations. If only front-wheel steering is supported, two front-wheel rheostats and two rear-wheel rheostats are connected in parallel; if four-wheel turning is supported, two four-wheel rheostats need to be added. When switching modes, the inner front and rear wheels use the same inner voltage signal, and the outer front and rear wheels use the same outer voltage signal.

[0141] In the present invention, from the maximum steering angle of the inner side of the support to the required angle of 90 degrees, it is recommended that the front wheel use the polar coordinate equation solution to minimize the space occupation, while the rear wheel is recommended to use the rectangular coordinate system parameter equation solution. This solution can theoretically accurately meet the differential ratio requirements.

[0142] In some embodiments, since the inner and outer steering angles caused by the traditional steering controller do not satisfy the Ackerman formula, a system error will be introduced. Therefore, two groups of signals can be averaged to reduce the error, one group using non-cross signals and the other group using cross signals.

[0143] Specifically, for the control of the front wheel motor, the distributed motor differential control device also includes a second speed rheostat. The distributed motor differential control device can eliminate system errors by organizing a circuit by connecting the second speed rheostat in series with the first speed rheostat. The first motor and the second motor respectively adjust their speeds according to the voltage difference between the corresponding contacts of the first speed rheostat and the second speed rheostat connected thereto.

[0144] For the control of the rear wheel motor, the distributed motor differential control device also includes a fourth speed rheostat. The distributed motor differential control device can reduce the system error by organizing the circuit by connecting the fourth speed rheostat in series with the third speed rheostat. The third motor and the fourth motor respectively adjust their speeds according to the voltage difference output by the corresponding contacts of the third speed rheostat and the fourth speed rheostat connected thereto.

[0145] For the first speed rheostat and the second speed rheostat, the inner and outer sliding areas of the first speed rheostat satisfy the polar coordinate equation (1) and the polar coordinate equation (2), while the inner and outer sliding areas of the second speed rheostat satisfy the polar coordinate equation (3) and the polar coordinate equation (4).

[0146] Similarly, for the third speed rheostat and the fourth speed rheostat, the inner and outer sliding areas of the third speed rheostat satisfy the rectangular coordinate equation (1) and the rectangular coordinate equation (2), while the inner and outer sliding areas of the fourth speed rheostat need to satisfy the rectangular coordinate equation (3) and the rectangular coordinate equation (4).

[0147] Specifically, combined Fig.12 , the principle of system error reduction is as follows:

[0148] First, assume that the crossover and non-crossover basic parameters U max , R max , R0 is equal. In the non-crossing case, it is assumed that the outer steering angle is smaller, that is, the inner steering angle has no error, such as Figure 4 As shown, the inner wheel control voltage U1 has no deviation, while the outer wheel voltage U2 has deviation. On the right side of the highest point in the outer area (decreasing area), U2 is smaller due to the smaller steering angle, and on the left side of the highest point (increasing area), U2 is larger due to the smaller steering angle. Figure 5 As shown, a smaller outer steering angle is equivalent to a larger inner steering angle. Similarly, on the left side of the highest point in the inner area (increasing area), U2 is larger due to the larger inner steering angle, and on the right side of the highest point (decreasing area), U2 is smaller due to the larger steering angle. Obviously, according to the corresponding relationship between the inner and outer angles, it is easy to know that the U2 error is exactly opposite in the cross and non-cross modes. Therefore, the average of the two sets of signals can reduce the error. Similarly, it is also true for the rear wheels.

[0149] Fig.12 In the protection resistor R 10 Connected in series with the cross resistor and the non-cross resistor, the power supply working voltage is V; the maximum resistance of the differential resistor is R max ; Left effective differential resistance R L (α); right effective differential resistance R R (β); Motor speed control signal voltage U:

[0150]

[0151] Due to the characteristics of the system error introduced by the speed rheostat, R L With R R If one is too large, the other must be too small, so this simple circuit can reduce the system error.

[0152] In another preferred embodiment, the automobile of this embodiment includes a first wheel, a second wheel, and a steering mechanism for driving the first wheel and the second wheel to steer, and also includes the Braun motor differential control device of the above embodiment.

[0153] This embodiment uses a curve equation that meets the requirements to construct a control rheostat, and adjusts the resistance value by different steering angles, so that the corresponding motor speed control signal is automatically obtained when the car turns, and can achieve real-time, efficient and reliable differential control.

[0154] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0155] It can be understood that the above embodiments only express the preferred implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the utility model. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the utility model, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the utility model. Therefore, all equivalent changes and modifications made to the scope of the claims of the utility model should belong to the scope covered by the claims of the utility model.

Claims

1. A distributed motor differential control device for automobile steering control, wherein the automobile comprises a first wheel, a second wheel, and a steering mechanism for driving the first wheel and the second wheel to steer, characterized in that: The distributed motor differential control device comprises a first motor and a second motor that respectively drive the first wheel and the second wheel to rotate, and two first speed rheostats that are respectively connected to the first motor and the second motor; The first speed rheostat comprises an inner sliding vane area corresponding to the inner wheel and an outer sliding vane area corresponding to the outer wheel, wherein the curve shapes of the inner sliding vane area and the outer sliding vane area are determined according to the Ackerman formula; The steering mechanism is connected to and drives the first speed rheostat to adjust the output resistance value according to the steering angle and output a speed control signal according to the resistance value; The first motor and the second motor adjust their rotation speeds respectively according to the speed control signal of the first rotation speed rheostat connected thereto.

2. The distributed motor differential speed control device according to claim 1, characterized in that: The first speed rheostat comprises a linear resistor / coil and a contact slider; One end of the initial position of the resistor / coil is fixed at the rotation center, and the other end is initially located at a polar angle of 0. The maximum effective variable resistance area length R max ≥ Maximum pole diameter, the rotation center end is connected to the negative pole of the power supply, and the other end of the resistor / coil is connected to the positive pole of the power supply; If the contact slide is fixed, the resistor / coil rotates synchronously with the steering mechanism; or, if the resistor / coil is fixed, the contact slide rotates synchronously with the steering mechanism in the opposite direction.

3. The distributed motor differential speed control device according to claim 1, characterized in that: The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the polar coordinate equation (I) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the polar coordinate equation (II) or its equivalent equation; The polar coordinate equation (I) is: R1 = R0*f(α); The polar coordinate equation (II) is: R2 = R0*g(β); in, c=a / b, a is the wheelbase of the left and right wheels on the same horizontal line, b is the wheelbase of the front and rear wheels on the same horizontal line, α is the inner steering angle when the car turns, β is the outer steering angle when the car turns, and R0 is the maximum effective length of the resistor / coil of the speed rheostat; or The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the polar coordinate equation (III) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the polar coordinate equation (IV) or its equivalent equation; The polar coordinate equation (III) is: R1 = R0 / f(α); The polar coordinate equation (IV) is: R2 = R0 / g(β); At this time, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor.

4. The distributed motor differential speed control device according to claim 3, characterized in that: The distributed motor differential speed control device further includes a second speed rheostat, which is connected in series with the first speed rheostat to reduce system errors, and the first motor and the second motor respectively adjust their speeds according to the voltage difference between corresponding contacts of the first speed rheostat and the second speed rheostat connected thereto; Among them, the curve shape of the inner sliding area of ​​the first speed rheostat satisfies the polar coordinate equation (1), and the curve shape of the outer sliding area of ​​the first speed rheostat satisfies the polar coordinate equation (2); the curve shape of the inner sliding area of ​​the second speed rheostat satisfies the polar coordinate equation (3), and the curve shape of the outer sliding area of ​​the second speed rheostat satisfies the polar coordinate equation (4).

5. The distributed motor differential speed control device according to claim 1, characterized in that: The distributed motor differential control device further comprises a power supply, wherein the positive electrode of the power supply is connected to the outer sliding end of the first speed rheostat connected to the first motor and the inner sliding end of the first speed rheostat connected to the second motor, and the negative electrode of the power supply is connected to the inner sliding end of the first speed rheostat connected to the first motor and the outer sliding end of the first speed rheostat connected to the second motor; or The speed control signal includes a speed voltage control signal or a speed current control signal output according to the resistance value conversion; the first motor and the second motor adjust their speeds according to the corresponding speed voltage control signal or speed current control signal.

6. The distributed motor differential speed control device according to claim 1, characterized in that: The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the rectangular coordinate equation (5) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the rectangular coordinate equation (6) or its equivalent equation; The rectangular coordinate equation (V) is: Y1 = R0*f(α), X1 = D0*α; The rectangular coordinate equation (VI) is: Y2 = R0*g(β), X2 = -D0*β; Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the ratio of the circumference of a circle to the radius of the circle; D0 is the radius of the unfolded circle, which is equivalent to the pitch radius of the steering gear; the maximum turning angle of the outer area is less than 90 degrees; R0 is the maximum effective length of the resistor / coil; or The curve shape of the inner sliding vane area of ​​the first speed rheostat satisfies the rectangular coordinate equation (VII) or its equivalent equation, and the curve shape of the outer sliding vane area satisfies the rectangular coordinate equation (VIII) or its equivalent equation; The rectangular coordinate equation (VII) is: Y1 = R0 / f(α), X1 = D0*α; The rectangular coordinate equation (VIII) is: Y2=R0 / g(β), X2=-D0*β; At this time, the output resistance values ​​of the two first speed rheostats cross-control the first motor and the second motor.

7. The distributed motor differential speed control device according to any one of claims 1 to 6, characterized in that: The automobile further comprises a third wheel and a fourth wheel, the steering mechanism drives the third wheel and the fourth wheel to rotate, and the distributed motor differential control device further comprises a third motor and a fourth motor respectively driving the third wheel and the fourth wheel to rotate, and two third speed rheostats respectively connected to the third motor and the fourth motor; The curve shape of the inner sliding plate area of ​​the third speed rheostat satisfies the rectangular coordinate equation (I) or its equivalent equation, and the curve shape of the outer sliding plate area satisfies the rectangular coordinate equation (II) or its equivalent equation; The rectangular coordinate equation (I) is: Y3 = R0*cos(α)*f(α), X3 = D0*α; The rectangular coordinate equation (II) is: Y4 = R0*cos(β)*g(β), X4 = -D0*β; Where, 0≤α≤pi / 2, 0≤β≤pi / 2, pi is the circumference of a circle; the maximum angle of the outer side satisfies ctg(β)=c; D0 is the radius of the unfolded circle, which is equivalent to the pitch radius of the steering gear; or The curve shape of the inner sliding plate area of ​​the third speed rheostat satisfies the rectangular coordinate equation (three) or its equivalent equation, and the curve shape of the outer sliding plate area satisfies the rectangular coordinate equation (four) or its equivalent equation; The rectangular coordinate equation (III) is: X3=D0*α; The rectangular coordinate equation (IV) is: X4 = -D0*β; At this time, the output resistance values ​​of the two third speed rheostats cross-control the third motor and the fourth motor.

8. The distributed motor differential speed control device according to claim 7, characterized in that: The distributed motor differential speed control device further includes a fourth speed rheostat, which is connected in series with the third speed rheostat to reduce system errors, and the third motor and the fourth motor respectively adjust their speeds according to the voltage difference output by the corresponding contacts of the third speed rheostat and the fourth speed rheostat connected thereto; Among them, the curve shape of the inner sliding area of ​​the third speed rheostat satisfies the rectangular coordinate equation (one), and the curve shape of the outer sliding area of ​​the third speed rheostat satisfies the rectangular coordinate equation (two); the curve shape of the inner sliding area of ​​the fourth speed rheostat satisfies the rectangular coordinate equation (three), and the curve shape of the outer sliding area of ​​the fourth speed rheostat satisfies the rectangular coordinate equation (four).

9. The distributed motor differential speed control device according to claim 7, characterized in that: In the four-wheel turning mode of the four-motor vehicle model, the control device further includes two four-wheel resistors respectively connected in parallel with the first speed resistor; The equation satisfied by the curve shape of the inner and outer sliding vane areas of the four-wheel rheostat is the same as that of the first speed rheostat, and at this time the parameter c=a / 2b.

10. An automobile, characterized in that: It includes the distributed motor differential speed control device as described in any one of claims 1 to 9.

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