Electronic steering assembly and electric vehicle

Abstract

The present invention provides an electronic steering assembly, which relates to the field of automobile design technology. The electronic steering assembly includes: a rear axle, the rear axle is provided with a rear wheel shaft, and the rear wheel shaft is driven to rotate by the power system of the automobile; a front axle, the front axle is provided with a steering mechanism, a left shaft seat and a right shaft seat, and the left and right shaft seats are respectively provided on the left and right sides of the steering mechanism; the steering mechanism can drive the left and right shaft seats to turn at the same time, and the extension line of the shaft on the left shaft seat and the extension line of the shaft on the right shaft seat always intersect with the extension line of the rear wheel shaft. The electronic steering assembly of the present invention is provided with a steering mechanism on the front axle, and the rear axle is driven forward by the power system. The steering function components and the drive function components are separated and arranged, which can bring about the effects of greater steering torque, stronger load capacity and higher reliability. On this basis, the present invention also provides an electric vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile design, and in particular to an electronic steering assembly and an electric vehicle. Background Art

[0002] Currently, walking robots on the market are either wheel-driven or equipped with legs. Robots designed to stabilize loads typically have four wheels, with the two front wheels driving and steering, typically using two-wheel differential steering. This steering method suffers from low torque and insufficient steering power under heavy loads, limiting its application. Summary of the Invention

[0003] The purpose of the present invention is to provide an electronic steering assembly, which arranges the steering mechanism and drive system on the front axle and rear axle respectively, which can reliably improve the steering torque of the entire vehicle and improve the maximum load, steering power and carrying reliability of the walking electric robot.

[0004] Another object of the present invention is to provide an electric vehicle that can reduce the mass of the suspension and chassis as much as possible, thereby ensuring that the effective load of the electric vehicle is increased under the premise of sufficient torque.

[0005] The embodiment of the present invention is achieved as follows:

[0006] An electronic steering assembly comprises: a rear axle, the rear axle being provided with a rear wheel shaft, the rear wheel shaft being driven to rotate by the power system of the automobile; a front axle, the front axle being provided with a steering mechanism, a left shaft seat and a right shaft seat, the left shaft seat and the right shaft seat being provided on the left and right sides of the steering mechanism respectively; the steering mechanism being capable of driving the left and right shaft seats to steer simultaneously, and the extension lines of the shafts on the left and right shaft seats always intersecting with the extension lines of the rear wheel shafts.

[0007] In a preferred embodiment of the present invention, the steering mechanism includes a reduction gear unit, a steering swing arm, a first pull rod, and a second pull rod; the reduction gear unit is installed on the front axle, and the steering swing arm is arranged on the reduction gear unit; a first torque arm is arranged at the front end of the left-turn axle seat, and a second torque arm is arranged at the rear end; a third torque arm is arranged at the rear end of the right-turn axle seat; the left-turn axle seat, the steering swing arm, and the right-turn axle seat are all hinged to the front axle, one end of the first pull rod is hinged to the free end of the steering swing arm, and the other end of the first pull rod is hinged to the first torque arm; one end of the second pull rod is hinged to the second torque arm, and the other end of the second pull rod is hinged to the third torque arm. The technical effect is that by utilizing the hinged relationship and fixed connection relationship of multiple components, the reduction gear unit can drive the steering swing arm to realize the same-direction swing of the left-turn axle seat and the right-turn axle seat.

[0008] In a preferred embodiment of the present invention, the vertical distance from the intersection of the first torque arm and the left-turn axle seat to the mid-section of the front axle is greater than the vertical distance from the intersection of the second torque arm and the left-turn axle seat to the mid-section of the front axle. This provides the following technical advantages: by setting different intersection positions, the deflection angle of the left front wheel, driven by the steering arm, can be greater or less than the deflection angle of the right front wheel.

[0009] In a preferred embodiment of the present invention, the vertical distance between the intersection of the first torque arm and the left-hand axle seat and the mid-section of the front axle is greater than the vertical distance between the intersection of the third torque arm and the right-hand axle seat and the mid-section of the front axle. This provides the following technical advantages: by using different mounting distances, the entire steering mechanism forms a structural design similar to an Ackermann trapezoid, achieving different steering force arms for the left and right axle seats, and ensuring that during the swing of the steering arm, the extension lines of the left and right axles intersect with the extension line of the rear wheel axle.

[0010] In a preferred embodiment of the present invention, the reduction gear assembly includes a spur gear reducer; the spur gear reducer is connected to the steering arm and is capable of driving the steering arm to swing. The technical effect is that the spur gear reducer has direct transmission, can reduce torque loss, and can compress the installation space of the equipment.

[0011] In a preferred embodiment of the present invention, the reduction ratio of the spur gear reducer is 15:1 to 25:1. The technical effect is that the reduction ratio can be set between 15:1 and 25:1, preferably 20:1, according to the operating characteristics of electric vehicles and robots.

[0012] In a preferred embodiment of the present invention, the reduction gear assembly further includes a brushless DC drive connected to the spur-tooth reducer and capable of driving the spur-tooth reducer. This technical advantage is that, because brushed motors utilize mechanical commutation, they suffer from short lifespans, high noise levels, low efficiency, and the tendency to generate sparks. Carbon brushes wear out severely over time and are prone to damage. Furthermore, wear generates large amounts of carbon dust, which can accelerate the drying of bearing oil and further increase motor noise. Brushless DC drives, however, avoid these drawbacks.

[0013] In a preferred embodiment of the present invention, the system further includes a controller and an angle sensor; both are mounted on the front axle, and the angle sensor, controller, and reduction gear assembly are electrically connected in sequence. The angle sensor is used to detect the rotation angles of the left and right axle seats. The technical effect is that the controller changes the front wheel's deflection angle or sets the desired rotation angle of the front wheels based on real-time steering angle data monitored by the angle sensor.

[0014] In a preferred embodiment of the present invention, the angle sensor is a rotary potentiometer. The technical effect is that the rotary potentiometer is preferably used as the angle sensor, and the deflection angle of the front wheel is calculated by collecting the resistance value, and the obtained value is accurate and fast.

[0015] An electric vehicle comprises wheels, a suspension, a power system, a frame and the above-mentioned electronic steering assembly; the wheels are arranged on the rear wheel shaft, the left shaft seat and the right shaft seat, the front axle and the rear axle are connected to the frame through the suspension, and the power system is arranged on the rear axle for driving the rear wheel shaft to rotate.

[0016] The beneficial effects of the embodiments of the present invention are:

[0017] 1. The electronic steering assembly sets the steering mechanism on the front axle, while the rear axle is driven by the power system. The steering function components and the drive function components are split and arranged, which can bring greater steering torque, stronger load capacity and higher reliability.

[0018] 2. The electric vehicle is equipped with the above-mentioned electronic steering assembly, which reduces the mass of the suspension and chassis as much as possible while ensuring sufficient torque, thereby increasing the effective load of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A first top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention;

[0021] Figure 2 A top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention when turning left;

[0022] Figure 3 A top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention when turning right;

[0023] Figure 4 A three-dimensional diagram of the front axle of the electronic steering assembly provided in embodiments 1 and 2 of the present invention;

[0024] Figure 5 A top view of the front axle of the electronic steering assembly provided in embodiments 1 and 2 of the present invention;

[0025] Figure 6A top view of the steering mechanism in the electronic steering assembly provided in embodiments 1 and 2 of the present invention;

[0026] Figure 7 This is the angle acquisition circuit of the electronic steering assembly provided in the second embodiment of the present invention.

[0027] In the figure: 100 - rear axle; 110 - rear wheel shaft; 200 - front axle; 210 - steering mechanism; 211 - reduction gear unit; 212 - steering swing arm; 213 - first tie rod; 214 - second tie rod; 220 - left axle seat; 230 - right axle seat; 300 - wheel. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0031] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0033] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0035] Figure 1 A first top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention;

[0036] Figure 2 A top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention when turning left;

[0037] Figure 3 A top view of the electronic steering assembly provided in embodiments 1 and 2 of the present invention when turning right;

[0038] Figure 4 A three-dimensional diagram of the front axle 200 in the electronic steering assembly provided in the first and second embodiments of the present invention;

[0039] Figure 5 A top view of the front axle 200 in the electronic steering assembly provided in Embodiments 1 and 2 of the present invention;

[0040] Figure 6 This is a top view of the steering mechanism 210 in the electronic steering assembly provided in embodiments 1 and 2 of the present invention.

[0041] First embodiment:

[0042] Please refer to Figures 1 to 6 , this embodiment provides an electronic steering assembly, which includes:

[0043] The rear axle 100 is provided with a rear wheel axle 110, which is driven to rotate by the vehicle's power system. The front axle 200 is provided with a steering mechanism 210, a left axle seat 220, and a right axle seat 230. When viewed from the rear axle 100 toward the front axle 200, the left axle seat 220 and the right axle seat 230 are respectively provided on the left and right sides of the steering mechanism 210. The steering mechanism 210 can drive the left and right axle seats 220 and 230 to steer simultaneously, and the extension lines of the rotation axes on the left and right axle seats 220 and 230 always intersect with the extension lines of the rear wheel axle 110.

[0044] Please refer to Figure 6 The steering mechanism 210 includes a reduction gear unit 211, a steering swing arm 212, a first pull rod 213, and a second pull rod 214; the reduction gear unit 211 is installed on the front axle 200, and the steering swing arm 212 is arranged on the reduction gear unit 211; a first torque arm is arranged at the front end of the left rotating axle seat 220, and a second torque arm is arranged at the rear end; a third torque arm is arranged at the rear end of the right rotating axle seat 230; the left rotating axle seat 220, the steering swing arm 212 and the right rotating axle seat 230 are all hinged to the front axle 200, one end of the first pull rod 213 is hinged to the free end of the steering swing arm 212, and the other end of the first pull rod 213 is hinged to the first torque arm; one end of the second pull rod 214 is hinged to the second torque arm, and the other end of the second pull rod 214 is hinged to the third torque arm. By utilizing the hinged relationship and fixed connection relationship of multiple components, the reduction gear unit 211 can drive the steering swing arm 212 to realize the same-direction swing of the left-hand shaft seat 220 and the right-hand shaft seat 230 .

[0045] Please refer to Figures 1 to 6 The vertical distance between the intersection of the first torque arm and the left shaft seat 220 and the middle section of the front axle 200 is greater than the vertical distance between the intersection of the second torque arm and the left shaft seat 220 and the middle section of the front axle 200. Figure 3 The vertical distance between the intersection of the first torque arm and the left axle seat 220 and the mid-section of the front axle 200 is greater than the vertical distance between the intersection of the third torque arm and the right axle seat 230 and the mid-section of the front axle 200. By adopting different installation distances, the entire steering mechanism 210 forms a structural design similar to an Ackermann trapezoid, achieving different steering force arms for the left and right axle seats 220 and 230, ensuring that the extension lines of the left and right axles intersect with the extension line of the rear wheel axle 110 during the swinging of the steering swing arm 212.

[0046] The electronic steering assembly of the above embodiment has a steering mechanism 210 disposed on the front axle 200, while the rear axle 100 is driven forward by the power system. The separation of the steering and drive functional components can achieve greater steering torque, stronger load capacity, and higher reliability. As needed, the maximum steering angle range of the left-hand axle seat 220 and the right-hand axle seat 230 is set to -40° to 40°, where 0° is directly forward, negative angles are for turning left, and positive angles are for turning right. When the steering angle of the left-hand axle seat 220 is -40°, the steering angle of the right-hand axle seat 230 is -31.5°. When the steering angle of the right-hand axle seat 230 is 40°, the steering angle of the right-hand axle seat 230 is 31.5°.

[0047] Please refer to Figure 4 On the basis of the above embodiment, the reduction gear unit 211 includes a spur gear reducer; the spur gear reducer is connected to the steering swing arm 212 and can drive the steering swing arm 212 to swing.

[0048] Please refer to Figure 4 , based on the above embodiment, the reduction ratio of the spur gear reducer is 15:1 to 25:1, preferably set to 20:1.

[0049] Please refer to Figure 4 On the basis of the above embodiment, the speed reducer assembly 211 further includes a brushless DC driver; the brushless DC driver is connected to the spur gear reducer and can drive the spur gear reducer to operate.

[0050] Second embodiment:

[0051] Figure 7 This is the angle acquisition circuit of the electronic steering assembly provided in the second embodiment of the present invention. Figures 1 to 7 This embodiment provides an electronic steering assembly, which is substantially the same as the electronic steering assembly of the first embodiment. The difference between the two is that the electronic steering assembly of this embodiment further includes a controller and an angle sensor; the controller and the angle sensor are both arranged on the front axle 200, and the angle sensor, the controller and the reducer unit 211 are electrically connected in sequence. The angle sensor is used to detect the rotation angles of the left rotating shaft seat 220 and the right rotating shaft seat 230.

[0052] Please refer to Figure 7 The angle sensor is a rotary potentiometer. The rotary potentiometer calculates the angle by collecting resistance values. In the figure, R1 is a series current-limiting resistor, R2 is a rotary potentiometer, V1 collects the voltage input to the potentiometer, and V2 collects the voltage after the knob is adjusted. The angle is linearly related to the potentiometer resistance value, so the potentiometer angle is:

[0053]

[0054] Where θ is the mechanical angle, R2' is the resistance from the potentiometer brush to GND, according to Ohm's law:

[0055]

[0056]

[0057] Where I is the branch current, then

[0058]

[0059] θ is the current angle.

[0060] In the electronic steering assembly of the above embodiment, the controller can change the deflection angle of the front wheels or set the required rotation angle of the front wheels according to the real-time steering angle data monitored by the angle sensor.

[0061] Furthermore, to improve angle control accuracy, the electronic steering assembly incorporates angle compensation into its angle control. This approach first estimates the current motor speed, then uses the current speed to calculate the angle after the motor stops, and then uses this angle for control. This addresses the issue of motor response lag.

[0062] Angle changes are achieved by the motor driving the reducer. When controlling the angle, the steering assembly must rotate a small distance in a relatively short time. However, when controlling the motor's speed, acceleration and deceleration are a process. If the motor is rotating rapidly and then suddenly set to zero, it will still rotate a certain distance. If not addressed, this can cause severe overshoot during control. On the other hand, the motor's acceleration and deceleration times are configurable values. The actual motor speed can be estimated by combining the motor's set speed with the acceleration and deceleration rates set by the motor controller. This speed is then compensated for the currently acquired angle before control is executed.

[0063] Estimate the motor speed by following these steps:

[0064] 1. Set the initial speed to 0. If the motor direction changes, the speed will also be set to 0.

[0065] 2. Determine the current state by comparing the previously set motor speed (pwm_out) with the calculated real speed (speed_real).

[0066] 3. If the speed set at the last moment is greater than the actual speed (pwm_out>speed_real), the motor accelerates, but the speed will not be greater than the set speed, so the real speed is updated:

[0067] speed real =speed real+Acc×Dt,speed real <speed set (0.5)

[0068] If the set rotational speed at the previous moment is less than the actual rotational speed (pwm_out < speed_real), the motor decelerates, but the speed will not be less than the set speed, then update the real speed:

[0069] speed real =speed real -Acc×Dt,speed real >speed set (0.6)

[0070] When the difference between the set speed and the current speed is relatively large, the motor needs an acceleration process to reach it. speed_real is the current speed estimated according to the acceleration. From this value, the angle that the motor will continue to rotate after the controller stops output can be calculated, and then this angle is compensated into the current angle to participate in the control, which can reduce the overshoot phenomenon.

[0071] The angle compensation is: the current angle position + the angle rotated during the deceleration process after the current speed stops,

[0072] [[ID=2,7]]The following is the process of adding the compensation angle:

[0073] deg est =deg cur +speed real ×dt×0.5 (0.7)

[0074] PID control

[0075] The PID controller consists of a proportional unit (P), an integral unit (I), and a derivative unit (D). The relationship between its input e(t) and output u(t) is:

[0076]

[0077] In the formula, the upper and lower limits of the integral are 0 and t respectively, so its transfer function is:

[0078]

[0079] Where kp is the proportional coefficient; TI is the integral time constant; and TD is the differential time constant. PID control is based on proportional control. Integral control eliminates steady-state error but may increase overshoot. Differential control accelerates the response of systems with high inertia and reduces overshoot. Since the steering system stops outputting after reaching the desired position, there is no steady-state error. However, it is significantly affected by response speed and inertia. To address these issues, a PD controller is used.

[0080] out=Kp×err+kd×err d (0.10)

[0081] err=deg set -deg est (0.11)

[0082]

[0083] Third embodiment:

[0084] This embodiment provides an electric vehicle, which includes wheels 300, a suspension, a power system, a frame, and the electronic steering assembly as described above; the wheels 300 are arranged on the rear wheel shaft 110, the left shaft seat 220 and the right shaft seat 230, the front axle 200 and the rear axle 100 are connected to the frame through the suspension, and the power system is arranged on the rear axle 100 for driving the rear wheel shaft 110 to rotate.

[0085] The electric vehicle of the above embodiment is provided with the above electronic steering assembly, which reduces the mass of the suspension and chassis as much as possible while ensuring sufficient torque, thereby increasing the effective load of the electric vehicle.

[0086] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An electronic steering assembly, characterized in that: include: A rear axle, wherein the rear axle is provided with a rear wheel shaft, and the rear wheel shaft is driven to rotate by the power system of the vehicle; The front axle is provided with a steering mechanism, a left-hand axle seat and a right-hand axle seat, wherein the left-hand axle seat and the right-hand axle seat are respectively provided on the left and right sides of the steering mechanism; The steering mechanism can drive the left-hand shaft seat and the right-hand shaft seat to turn simultaneously, and the extension line of the rotating shaft on the left-hand shaft seat and the extension line of the rotating shaft on the right-hand shaft seat always intersect the extension line of the rear wheel rotating shaft; The steering mechanism includes a reduction gear unit, a steering swing arm, a first pull rod, and a second pull rod; The reduction gear unit is installed on the front axle, and the steering swing arm is arranged on the reduction gear unit; The front end of the left-hand shaft seat is provided with a first torque arm, and the rear end is provided with a second torque arm; the rear end of the right-hand shaft seat is provided with a third torque arm; The left-hand shaft seat, the steering swing arm, and the right-hand shaft seat are all hinged to the front axle, one end of the first tie rod is hinged to the free end of the steering swing arm, and the other end of the first tie rod is hinged to the first torque arm; One end of the second pull rod is hinged to the second torque arm, and the other end of the second pull rod is hinged to the third torque arm; A vertical distance from the intersection of the first torque arm and the left rotating shaft seat to the mid-section of the front axle is greater than a vertical distance from the intersection of the second torque arm and the left rotating shaft seat to the mid-section of the front axle, and is greater than a vertical distance from the intersection of the third torque arm and the right rotating shaft seat to the mid-section of the front axle.

2. The electronic steering assembly according to claim 1, characterized in that: The speed reducer assembly includes a spur gear reducer; the spur gear reducer is connected to the steering swing arm and can drive the steering swing arm to swing.

3. The electronic steering assembly according to claim 2, characterized in that: The reduction ratio of the spur gear reducer is 15:1 to 25:

1.

4. The electronic steering assembly according to claim 2, characterized in that: The reduction gear unit further includes a brushless DC driver; the brushless DC driver is connected to the spur gear reducer and can drive the spur gear reducer to operate.

5. The electronic steering assembly according to claim 1, characterized in that: It also includes a controller and an angle sensor; the controller and the angle sensor are both arranged on the front axle, the angle sensor, the controller and the reducer group are electrically connected in sequence, and the angle sensor is used to detect the rotation angles of the left-turning shaft seat and the right-turning shaft seat.

6. The electronic steering assembly according to claim 5, characterized in that: The angle sensor is a rotary potentiometer.

7. An electric vehicle, characterized in that: It includes wheels, a suspension, a power system, a frame and the electronic steering assembly according to any one of claims 1 to 6; the wheels are arranged on the rear wheel shaft, the left shaft seat and the right shaft seat, the front axle and the rear axle are connected to the frame through the suspension, and the power system is arranged on the rear axle for driving the rear wheel shaft to rotate.

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