A drive axle tilt adjustable suspension system, vehicle and control method

Abstract

This application relates to a suspension system, vehicle, and control method with adjustable drive axle tilt angle. The suspension system includes a frame, a tilt sensor, and a controller. A middle axle assembly and a rear axle assembly are spaced apart at the bottom of the frame. A crossbeam is provided between the middle axle assembly and the rear axle assembly, and the crossbeam is fixed to the frame. The middle axle assembly is connected to the bottom of the crossbeam via a first lower thrust rod, and the rear axle assembly is connected to the bottom of the crossbeam via a second lower thrust rod. The tilt sensor is disposed on the middle axle assembly and the rear axle assembly, and is used to measure the tilt angle of the middle axle and the tilt angle of the rear axle. The controller is signal-connected to the tilt sensor. A hydraulic unit is provided in both the first and second lower thrust rods, and the hydraulic unit is signal-connected to the controller. The controller is used to adjust the opening of the hydraulic unit according to changes in the tilt angle of the middle axle and the tilt angle of the rear axle, thereby changing the length of at least one of the first and second lower thrust rods.

Description

Technical Field

[0001] This application relates to the field of vehicle suspension, specifically to a suspension system, vehicle, and control method with adjustable drive axle tilt angle. Background Technology

[0002] Currently, commercial vehicles typically employ multi-axle drive to meet heavy load requirements. To balance the load distribution among the drive axles and ensure good wheel contact performance, the rear suspension system of commercial vehicles often uses a balanced suspension system. The axle is connected to the frame via leaf spring assembly and balance shaft bracket, and is connected to the frame via thrust rod assembly, thus forming a four-bar structure that constrains the axle's motion trajectory. The thrust rod plays a role in transmitting longitudinal and lateral forces between the axle and the frame, and in determining the position and attitude of the axle relative to the frame.

[0003] In related technologies, during actual vehicle operation, the axle will pitch due to changes in load, road surface undulations, and vehicle acceleration, causing changes in the drive axle tilt angle. Since the thrust rod is a rigid component of fixed length, the suspension system passively adapts to the changes in drive axle tilt angle, resulting in a mismatch in the working angle of the universal joints at both ends of the drive shaft. This causes the universal joints to exhibit non-uniform speed effects, generating periodic speed fluctuations and torsional vibrations. This not only increases the noise of the transmission system but also accelerates the wear of the universal joints and drive shaft, reducing the service life of the transmission system.

[0004] Therefore, it is necessary to design a suspension system with adjustable drive axle tilt angle to overcome the above problems. Summary of the Invention

[0005] This application provides a suspension system, vehicle, and control method with adjustable drive axle tilt angle, which can solve the technical problem in related technologies where the thrust rod is a rigid component of fixed length, and the suspension system passively adapts to changes in drive axle tilt angle, resulting in mismatch of the working angle of the universal joints at both ends of the drive shaft, causing non-uniform speed effect of the universal joints, and generating periodic speed fluctuations and torsional vibrations.

[0006] In a first aspect, embodiments of this application provide a suspension system with adjustable drive axle tilt angle, comprising: a frame, a tilt sensor, and a controller. The frame has a middle axle assembly and a rear axle assembly spaced apart at its bottom. A crossbeam is provided between the middle axle assembly and the rear axle assembly, and the crossbeam is fixed to the frame. Two first upper thrust rods are provided in the middle of the middle axle assembly, and the two first upper thrust rods are respectively connected to the top of the crossbeam. Two second upper thrust rods are provided in the middle of the rear axle assembly, and the two second upper thrust rods are respectively connected to the top of the crossbeam. The middle axle assembly is connected to the rear axle assembly via a first lower thrust rod. The bottom of the crossbeam is connected, and the rear axle assembly is connected to the bottom of the crossbeam via a second lower thrust rod; the tilt sensor is disposed in the middle axle assembly and the rear axle assembly, and the tilt sensor is used to measure the tilt angle of the middle axle and the tilt angle of the rear axle; the controller is signal-connected to the tilt sensor, and a hydraulic unit is provided in both the first lower thrust rod and the second lower thrust rod, and the hydraulic unit is signal-connected to the controller, and the controller is used to adjust the opening of the hydraulic unit according to the changes in the tilt angle of the middle axle and the tilt angle of the rear axle, so that the length of at least one of the first lower thrust rod and the second lower thrust rod changes.

[0007] In conjunction with the first aspect, in one embodiment, two first upper thrust rods are arranged crosswise and are respectively connected to the end of the crossbeam, and two second upper thrust rods are arranged crosswise and are respectively connected to the end of the crossbeam.

[0008] In conjunction with the first aspect, in one embodiment, the middle axle assembly and the rear axle assembly are connected by a drive shaft, the drive shaft is equipped with a speed sensor, the speed sensor is signal-connected to the controller, and the controller is used to calculate the current equivalent angle of the drive shaft based on the speed signal.

[0009] In conjunction with the first aspect, in one embodiment, the rear axle assembly is provided with a load sensor, the load sensor being signal-connected to the controller, and the controller being used to correct the target equivalent angle of the drive shaft in real time based on the load signal. Secondly, embodiments of this application provide a vehicle including a vehicle body, the vehicle body being provided with the aforementioned suspension system with adjustable drive axle tilt angle.

[0010] Thirdly, embodiments of this application provide a control method for a suspension system with an adjustable drive axle tilt angle, comprising the following steps: Calculate the equivalent included angle of the drive shaft based on the inclination angle of the middle axle and the inclination angle of the rear axle; If the equivalent angle of the drive shaft is greater than the set fluctuation threshold, then the length of at least one of the first and second lower thrust rods is changed until the equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

[0011] In conjunction with the third aspect, in one embodiment, calculating the equivalent included angle of the driveshaft based on the camber angle of the middle axle and the camber angle of the rear axle includes: Calculate the universal joint angle of the drive shaft based on the tilt angle of the middle axle and the tilt angle of the rear axle; Calculate the equivalent included angle of the drive shaft based on the universal joint angle of the drive shaft.

[0012] In conjunction with the third aspect, in one embodiment, controlling the length change of at least one of the first and second lower thrust rods until the equivalent included angle of the drive shaft is less than or equal to a set fluctuation threshold includes: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, the adjustment amount of at least one of the first lower thrust rod and the second lower thrust rod is calculated; The length of at least one of the first and second lower thrust rods is changed according to the calculated adjustment amount until the current equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

[0013] In conjunction with the third aspect, in one embodiment, calculating the adjustment amount of at least one of the first and second lower thrust rods based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft includes: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, the change in at least one of the middle axle tilt angle and the rear axle tilt angle that needs to be adjusted is calculated using PID parameters. By using the calculated change in at least one of the middle axle tilt angle and the rear axle tilt angle, the adjustment amount of at least one of the first and second lower thrust rods can be calculated.

[0014] In conjunction with the third aspect, in one embodiment, before calculating the equivalent included angle of the driveshaft based on the middle axle camber angle and the rear axle camber angle, the following steps are included: Perform Fast Fourier Transform or waveform analysis on rotational speed data over a continuous time period to extract the amplitude of rotational speed fluctuations; Based on the kinematic model of the drive shaft, the equivalent angle of the current drive shaft can be deduced by using the amplitude of the speed fluctuation.

[0015] The beneficial effects of the technical solutions provided in this application include: By incorporating hydraulic units within the first and second lower thrust rods, the lengths of these rods can be adjusted according to changes in the tilt angles of the middle and rear axles. This enables active correction of the drive axle tilt angle, resolving the technical problem in related technologies where the thrust rods are rigid components of fixed length. This results in the suspension system passively adapting to changes in the drive axle tilt angle, leading to a mismatch in the working angles of the universal joints at both ends of the drive shaft, causing non-uniform speed effects in the universal joints, and generating periodic speed fluctuations and torsional vibrations. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of a suspension system with adjustable drive axle tilt angle provided in an embodiment of this application; Figure 2 A top view of a suspension system with adjustable drive axle tilt angle provided in an embodiment of this application; Figure 3 A side view of a suspension system with adjustable drive axle tilt angle provided in an embodiment of this application; Figure 4 A schematic diagram of the rear axle assembly, the second upper thrust rod, and the second lower thrust rod provided in the embodiments of this application; Figure 5 The schematic diagram shows the camber angle of the middle axle and the camber angle of the rear axle provided in the embodiments of this application.

[0018] In the diagram: 1. Chassis; 2. Middle axle assembly; 3. Rear axle assembly; 4. Crossbeam; 5. First upper thrust rod; 6. Second upper thrust rod; 7. First lower thrust rod; 8. Second lower thrust rod; 9. Drive shaft. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] This application provides a suspension system, vehicle, and control method with adjustable drive axle tilt angle. It can solve the technical problem that, due to the fixed length of the thrust rod as a rigid component, the suspension system passively adapts to changes in drive axle tilt angle, resulting in mismatch of the working angles of the universal joints at both ends of the drive shaft, causing non-uniform speed effects in the universal joints, and generating periodic speed fluctuations and torsional vibrations.

[0021] See Figures 1-4As shown, this application embodiment provides a suspension system with adjustable drive axle tilt angle, comprising: a frame 1, a tilt sensor, and a controller. A middle axle assembly 2 and a rear axle assembly 3 are spaced apart at the bottom of the frame 1. A crossbeam 4 is provided between the middle axle assembly 2 and the rear axle assembly 3, and the crossbeam 4 is fixed to the frame 1. Two first upper thrust rods 5 are provided in the middle of the middle axle assembly 2, and the two first upper thrust rods 5 are respectively connected to the top of the crossbeam 4. Two second upper thrust rods 6 are provided in the middle of the rear axle assembly 3, and the two second upper thrust rods 6 are respectively connected to the top of the crossbeam 4. The middle axle assembly 2 is connected by a first lower thrust rod. Rod 7 is connected to the bottom of the crossbeam 4, and the rear axle assembly 3 is connected to the bottom of the crossbeam 4 via the second lower thrust rod 8; the tilt sensor is installed in the middle axle assembly 2 and the rear axle assembly 3, and the tilt sensor is used to measure the tilt angle of the middle axle and the tilt angle of the rear axle; the controller is signal-connected to the tilt sensor, and both the first lower thrust rod 7 and the second lower thrust rod 8 are provided with hydraulic units, and the hydraulic units are signal-connected to the controller, and the controller is used to adjust the opening of the hydraulic units according to the changes in the tilt angle of the middle axle and the tilt angle of the rear axle, so that the length of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 changes.

[0022] In this embodiment, a balance shaft bracket is connected to the bottom of the crossbeam 4. Both the first lower thrust rod 7 and the second lower thrust rod 8 are connected to the balance shaft bracket. The middle axle housing, the first upper thrust rod 5, the crossbeam 4, and the first lower thrust rod 7 form a quadrilateral. The rear axle housing, the second upper thrust rod 6, the crossbeam 4, and the second lower thrust rod 8 also form a quadrilateral. In the four-bar linkage, changing the length of the first upper thrust rod 5 or the first lower thrust rod 7 changes the tilt angle of the middle axle. Changing the length of the second upper thrust rod 6 or the second lower thrust rod 8 changes the tilt angle of the rear axle. Both the first lower thrust rod 7 and the second lower thrust rod 8 have hydraulic chambers. The tilt sensor is located in the non-rotating parts of the middle axle housing and the rear axle housing. The tilt sensor collects signals of the center axle tilt angle and the rear axle tilt angle in real time. The hydraulic unit is installed in the hydraulic chamber. The hydraulic unit includes an electro-hydraulic proportional valve. Regardless of whether the vehicle is stationary or in motion, the controller adjusts the opening of the electro-hydraulic proportional valve according to the changes in the center axle tilt angle and the rear axle tilt angle, thereby adjusting the amount of oil entering the hydraulic chamber. This drives at least one of the first lower thrust rod 7 and the second lower thrust rod 8 to extend or retract, thereby controlling the axle tilt angle in real time and dynamically, suppressing vehicle body roll or pitch, and optimizing tire contact patch. This enables the vehicle to actively adjust the rear axle tilt angle when turning, generating a roll resistance torque opposite to the steering trend. On slippery roads, it adjusts the tire contact angle, improves tire grip, and enhances the active safety of commercial vehicles.

[0023] This embodiment incorporates the hydraulic unit within the first lower thrust rod 7 and the second lower thrust rod 8, allowing the lengths of the first lower thrust rod 7 and the second lower thrust rod 8 to change according to variations in the middle axle tilt angle and the rear axle tilt angle. This enables active correction of the drive axle tilt angle, solving the technical problem in related technologies where, due to the thrust rod being a rigid component of fixed length, the suspension system passively adapts to changes in the drive axle tilt angle, leading to a mismatch in the working angles of the universal joints at both ends of the drive shaft, resulting in non-uniform speed effects in the universal joints and causing periodic speed fluctuations and torsional vibrations.

[0024] Further, see Figures 1-4 As shown, in some embodiments, the two first upper thrust rods 5 are arranged crosswise, and the two first upper thrust rods 5 are respectively connected to the ends of the crossbeam 4; the two second upper thrust rods 6 are arranged crosswise, and the two second upper thrust rods 6 are respectively connected to the ends of the crossbeam 4.

[0025] In this embodiment, one end of each of the two first upper thrust rods 5 converges at the middle axle assembly 2, and the other ends of each of the two second upper thrust rods 6 are respectively connected to the end of the crossbeam 4. One end of each of the two second upper thrust rods 6 converges at the rear axle assembly 3, and the other ends of each of the two second upper thrust rods 6 are respectively connected to the end of the crossbeam 4. The lengths of the first upper thrust rods 5 and the second upper thrust rods 6 do not change.

[0026] Further, see Figures 1-3 As shown, in some embodiments, the middle axle assembly 2 and the rear axle assembly 3 are connected by a drive shaft 9. The drive shaft 9 is equipped with a speed sensor, which is signal-connected to the controller. The controller is used to calculate the current equivalent angle of the drive shaft based on the speed signal.

[0027] In this embodiment, the middle axle is connected to the rear axle via the drive shaft 9. The tilt angle of the middle axle and the tilt angle of the rear axle directly affect the angle of the drive shaft 9. The speed sensor collects the speed signal in real time. The controller receives the speed signal and performs fast Fourier transform or waveform analysis on the speed data over a continuous time period to extract speed fluctuation characteristics, such as speed fluctuation amplitude, speed fluctuation frequency, and speed fluctuation phase.

[0028] Further, see Figures 1-3 As shown, in some embodiments, the rear axle assembly 3 is provided with a load sensor, which is signal-connected to the controller, and the controller is used to correct the target equivalent angle of the drive shaft in real time based on the load signal.

[0029] In this embodiment, when the vehicle is heavily loaded, the universal joint angles at both ends of the drive shaft 9 will change, and the initial installation phase of the universal joint will change. The controller receives the signal from the load sensor and corrects the target equivalent angle of the drive shaft and the PID parameters in real time, so that the vehicle can maintain a good balance.

[0030] Further, see Figures 1-4 As shown, in some embodiments, a vehicle includes a body equipped with the aforementioned drive axle tilt-adjustable suspension system.

[0031] In this embodiment, the vehicle body is equipped with a suspension system with adjustable drive axle tilt angle. Regardless of whether the vehicle is stationary or in motion, the controller adjusts the opening of the electro-hydraulic proportional valve according to the changes in the tilt angle of the middle axle and the rear axle, thereby adjusting the amount of oil entering the hydraulic chamber and driving at least one of the first lower thrust rod 7 and the second lower thrust rod 8 to extend or retract, thereby controlling the axle tilt angle in real time and dynamically. The suspension system with adjustable drive axle tilt angle is suitable for urban sanitation vehicles that require frequent starts and stops and cement mixer trucks with large loads.

[0032] This application provides a control method for a suspension system with adjustable drive axle tilt angle, which includes the following steps: S1: Calculate the equivalent included angle of the drive shaft based on the tilt angle of the middle axle and the tilt angle of the rear axle.

[0033] S2: If the equivalent angle of the drive shaft is greater than the set fluctuation threshold, then control the length of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 to change until the equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

[0034] In this embodiment, as an example, the tilt angles of the middle and rear axles are monitored in real time during vehicle operation, and the tilt angle of the drive axle is actively adjusted to make the universal joint angle of the drive shaft tend to be balanced, thereby eliminating speed fluctuations and vibrations caused by mismatched angles, eliminating noise in the transmission system and improving the life of the transmission system. In an ideal state, the target equivalent angle of the drive shaft is equal to zero, the angles of the front and rear universal joints are completely balanced, and there is no speed fluctuation. Due to the suspension travel limitation, a fluctuation threshold is allowed. If the equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold, the controller does not act. If the equivalent angle of the drive shaft is greater than the set fluctuation threshold, the length of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 is changed. When the length of the second lower thrust rod 8 is extended, the lower connection point of the axle housing moves backward, the entire axle housing rotates counterclockwise, the input axis of the main reducer tilts upward, and the rear axle tilt angle increases. When the length of the second lower thrust rod 8 is shortened, the lower connection point of the axle housing moves forward, the entire axle housing rotates clockwise, the input axis of the main reducer tilts downward, and the rear axle tilt angle decreases.

[0035] Furthermore, in some embodiments, calculating the equivalent included angle of the driveshaft based on the camber angle of the middle axle and the camber angle of the rear axle includes: S101: Calculate the universal joint angle of the drive shaft based on the tilt angle of the middle axle and the tilt angle of the rear axle.

[0036] S102: Calculate the equivalent included angle of the drive shaft based on the universal joint angle of the drive shaft.

[0037] In this embodiment, as Figure 5 As shown, the middle axle tilt angle is related to the first lower thrust rod 7, the frame vertical line, and the middle axle center vertical line; the rear axle tilt angle is related to the second lower thrust rod 8, the frame vertical line, and the rear axle center vertical line. The middle axle tilt angle satisfies the following formula: In the formula For the inclination angle of the middle bridge, The angle between the line connecting the ends and the perpendicular bisector of the middle bridge. The rear axle camber angle is the angle between the line connecting the ends and the perpendicular line of the frame. The rear axle camber angle satisfies the following formula: In the formula For the rear axle tilt angle, The angle between the line connecting the ends and the perpendicular bisector of the rear axle. The angle between the end connection line and the vertical line of the frame is the angle between the end connection line and the outer ball joint connection line of the thrust rod. The inclination angle of the middle axle and the inclination angle of the rear axle are directly related to the universal joint angle. The equivalent angle of the drive shaft is an equivalent value, which reflects the degree of imbalance between the front and rear universal joint angles, the severity of speed fluctuations, and the additional load and vibration excitation level of the transmission system.

[0038] The equivalent included angle of the drive shaft satisfies the following formula: In the formula The equivalent included angle of the drive shaft. Let i be the angle of the i-th gimbal. The number of universal joints in a multi-universal joint configuration. Let be the leading angle of the rotation direction of the (j+1)th gimbal angle plane relative to the jth gimbal plane. Let be the phase angle of the universal joint forks at both ends of the j-th drive shaft 9. The universal joint angle of the drive shaft is the universal joint angle between the middle axle and the drive shaft 9, and the universal joint angle between the rear axle and the drive shaft 9. The tilt angle of the middle axle and the tilt angle of the rear axle affect the universal joint angle of the drive shaft, thereby affecting the equivalent angle of the drive shaft.

[0039] Furthermore, in some embodiments, controlling the length change of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 until the equivalent included angle of the drive shaft is less than or equal to a set fluctuation threshold includes: S21: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, calculate the adjustment amount of at least one of the first lower thrust rod 7 and the second lower thrust rod 8.

[0040] S22: Change the length of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 according to the calculated adjustment amount until the current equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

[0041] In this embodiment, the change in bridge tilt angle satisfies the following formula: In the formula This is the vertical distance between the upper constraint point and the lower connection point of the thrust rod. This is the adjustment amount for the thrust rod. The change in the bridge's inclination angle, that is... Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, the adjustment amount of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 is calculated. The controller controls at least one of the first lower thrust rod 7 and the second lower thrust rod 8 to extend or shorten, and finely adjusts the middle axle tilt angle or the rear axle tilt angle until the current equivalent angle of the drive shaft converges to the set fluctuation threshold range.

[0042] Furthermore, in some embodiments, calculating the adjustment amount of at least one of the first lower thrust rod 7 and the second lower thrust rod 8 based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft includes: S211: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, use PID parameters to calculate the change in at least one of the middle axle tilt angle and the rear axle tilt angle that needs to be adjusted.

[0043] S212: Using the calculated change in at least one of the middle axle tilt angle and the rear axle tilt angle, calculate the adjustment amount of at least one of the first lower thrust rod 7 and the second lower thrust rod 8.

[0044] In this embodiment, the adjustment amount of the thrust rod satisfies the following formula: In the formula This is the adjustment amount for the thrust rod. This is the current equivalent included angle of the drive shaft. The target equivalent included angle of the drive shaft. For proportional gain, For integral gain, This is the differential gain.

[0045] Furthermore, in some embodiments, before calculating the equivalent included angle of the driveshaft based on the middle axle camber angle and the rear axle camber angle, the following steps are included: Step 1: Perform Fast Fourier Transform or waveform analysis on the rotational speed data over a continuous time period to extract the amplitude of rotational speed fluctuations.

[0046] Step 2: Based on the kinematic model of the drive shaft, the equivalent angle of the current drive shaft is deduced by using the amplitude of the speed fluctuation.

[0047] In this embodiment, the controller receives signals from the speed sensor and performs Fourier transform or waveform analysis on the speed data over a continuous time period to extract the speed fluctuation amplitude, speed fluctuation frequency, and speed fluctuation phase. The universal joint angle of the drive shaft can be determined based on the speed fluctuation amplitude, reflecting the severity of the imbalance between the front and rear universal joint angles. Based on the drive shaft kinematic model, the equivalent angle of the current drive shaft is calculated using the speed fluctuation amplitude. The universal joint angle of the drive shaft satisfies the following formula: In the formula The universal joint angle of the drive shaft. The average rotational speed, This is the load correction factor. This represents the amplitude of the rotational speed fluctuation.

[0048] The amplitude of speed fluctuation satisfies the following formula: , In the formula This is the maximum output speed. This is the minimum output speed. Input speed, The universal joint angle of the drive shaft. This represents the amplitude of the rotational speed fluctuation. To calculate the average rotational speed, the universal joint angle of the drive shaft is substituted into the formula for calculating the equivalent angle of the drive shaft to calculate the current equivalent angle of the drive shaft. The fundamental frequency fluctuation or harmonic frequency fluctuation can be determined based on the frequency fluctuation. The deviation from the reference position can be determined based on the phase of the speed fluctuation, such as the phase of the front universal joint fork. During the adjustment of the first lower thrust rod 7 or the second lower thrust rod 8, the speed sensor monitors the change in the amplitude of the rotational fluctuation in real time until the current equivalent angle of the drive shaft converges to the set fluctuation threshold range.

[0049] Under constant speed driving conditions, the driveshaft speed is relatively stable, which is conducive to extracting accurate fluctuation characteristics. The controller continuously and actively fine-tunes in real time, and the driveshaft 9 works in the optimal angle state for a long time. Under acceleration or deceleration conditions, the sudden change in driveshaft torque will cause transient torsion. The speed signal contains fluctuation components caused by non-angle factors. The controller reduces the weight coefficient of the driveshaft optimizer and pauses active adjustment to ensure that the current position of the thrust rod remains unchanged. Active adjustment is resumed after the vehicle speed stabilizes. Under heavy load conditions, the universal joint angles at both ends of the driveshaft 9 will change, changing the initial installation phase of the universal joint. According to the load signal, the controller corrects the target equivalent angle and PID coefficient of the driveshaft in real time, and the vehicle maintains a good balance.

[0050] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0051] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0052] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A suspension system with adjustable drive axle tilt angle, characterized in that, It includes: The vehicle frame has a middle axle assembly and a rear axle assembly spaced apart at its bottom. A crossbeam is provided between the middle axle assembly and the rear axle assembly, and the crossbeam is fixed to the vehicle frame. The middle axle assembly has two first upper thrust rods in its middle section, and the two first upper thrust rods are respectively connected to the top of the crossbeam. The rear axle assembly has two second upper thrust rods in its middle section, and the two second upper thrust rods are respectively connected to the top of the crossbeam. The middle axle assembly is connected to the bottom of the crossbeam through a first lower thrust rod, and the rear axle assembly is connected to the bottom of the crossbeam through a second lower thrust rod. A tilt sensor is disposed on the middle axle assembly and the rear axle assembly, and the tilt sensor is used to measure the tilt angle of the middle axle and the tilt angle of the rear axle. The controller is connected to the tilt sensor. Both the first and second lower thrust rods are equipped with hydraulic units, which are connected to the controller. The controller adjusts the opening of the hydraulic units according to the changes in the tilt angle of the middle axle and the tilt angle of the rear axle, so that the length of at least one of the first and second lower thrust rods changes.

2. The suspension system as described in claim 1, characterized in that, Two first upper thrust rods are arranged in a cross configuration, and each of the two first upper thrust rods is connected to the end of the crossbeam. Two second upper thrust rods are also arranged in a cross configuration, and each of the two second upper thrust rods is connected to the end of the crossbeam.

3. The suspension system as described in claim 1, characterized in that, The middle axle assembly and the rear axle assembly are connected by a drive shaft. The drive shaft is equipped with a speed sensor, which is connected to the controller. The controller is used to calculate the current equivalent angle of the drive shaft based on the speed signal.

4. The suspension system as described in claim 1, characterized in that, The rear axle assembly is equipped with a load sensor, which is signal-connected to the controller. The controller is used to correct the target equivalent angle of the drive shaft in real time based on the load signal.

5. A vehicle, characterized in that, It includes a vehicle body, the vehicle body being equipped with a suspension system with adjustable drive axle tilt as described in claim 1.

6. A control method for a suspension system with adjustable drive axle tilt angle, the suspension system comprising a vehicle frame, a middle axle assembly and a rear axle assembly spaced apart at the bottom of the vehicle frame, a crossbeam between the middle axle assembly and the rear axle assembly, two first upper thrust rods at the center of the middle axle assembly, two second upper thrust rods at the center of the rear axle assembly, the middle axle assembly being connected to the bottom of the crossbeam via first lower thrust rods, and the rear axle assembly being connected to the bottom of the crossbeam via second lower thrust rods, characterized in that... It includes the following steps: Calculate the equivalent included angle of the drive shaft based on the inclination angle of the middle axle and the inclination angle of the rear axle; If the equivalent angle of the drive shaft is greater than the set fluctuation threshold, then the length of at least one of the first and second lower thrust rods is changed until the equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

7. The control method as described in claim 6, characterized in that, The calculation of the equivalent included angle of the drive shaft based on the tilt angle of the middle axle and the tilt angle of the rear axle includes: Calculate the universal joint angle of the drive shaft based on the tilt angle of the middle axle and the tilt angle of the rear axle; Calculate the equivalent included angle of the drive shaft based on the universal joint angle of the drive shaft.

8. The control method as described in claim 6, characterized in that, The control of changing the length of at least one of the first and second lower thrust rods until the equivalent included angle of the drive shaft is less than or equal to a set fluctuation threshold includes: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, the adjustment amount of at least one of the first lower thrust rod and the second lower thrust rod is calculated; The length of at least one of the first and second lower thrust rods is changed according to the calculated adjustment amount until the current equivalent angle of the drive shaft is less than or equal to the set fluctuation threshold.

9. The control method as described in claim 8, characterized in that, The calculation of the adjustment amount for at least one of the first and second lower thrust rods based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft includes: Based on the deviation between the current equivalent angle of the drive shaft and the target equivalent angle of the drive shaft, the change in at least one of the middle axle tilt angle and the rear axle tilt angle that needs to be adjusted is calculated using PID parameters. By using the calculated change in at least one of the middle axle tilt angle and the rear axle tilt angle, the adjustment amount of at least one of the first and second lower thrust rods can be calculated.

10. The control method as described in claim 6, characterized in that, Before calculating the equivalent included angle of the driveshaft based on the middle axle tilt angle and the rear axle tilt angle, the following steps are included: Perform Fast Fourier Transform or waveform analysis on rotational speed data over a continuous time period to extract the amplitude of rotational speed fluctuations; Based on the kinematic model of the drive shaft, the equivalent angle of the current drive shaft can be deduced by using the amplitude of the speed fluctuation.

Images