All-terrain vehicle leap soft landing control method

Abstract

The invention discloses a leap soft landing control method for an all-terrain vehicle. The leap soft landing control method comprises the steps that leap action of the all-terrain vehicle is divided into a plurality of action states, the action state of the vehicle is judged by detecting dynamic data of the current vehicle, and corresponding damping control is distributed based on the action state so as to adjust damping of a suspension. By detecting dynamic data such as the leap posture, the vehicle body speed and the vehicle speed of the vehicle in real time, damping is adjusted in real time, the UTV landing process is optimized, and the purpose of soft landing is achieved.

Description

Technical Field

[0001] The invention relates to the field of suspension control of off-road vehicles, and in particular to a flying soft landing control method for an all-terrain vehicle. Background Art

[0002] As an off-road vehicle designed for rugged terrain, the suspension system of an all-terrain vehicle (UTV) is a key component to ensure driving stability and comfort. With the development of electronically controlled suspension technology, suspension based on CDC (Continuously Adjustable Damping Control) technology has gradually become mainstream, which can adjust the damping in real time according to the road conditions and improve the dynamic performance of the vehicle.

[0003] When UTVs are flying or jumping, they usually encounter high impact forces, which cause great vibrations to the vehicle body and passengers, affecting the driving experience and possibly causing safety hazards. The existing suspension system fails to fully solve the soft landing control during the flying process, especially when the height and body posture are unstable. It is difficult to effectively absorb the impact through conventional damping adjustment control methods, and the vibration during landing cannot be effectively suppressed, affecting the safety of the vehicle.

[0004] Most UTV suspension systems on the market today are mainly divided into two categories:

[0005] First, the traditional passive suspension has slow response, lacks adaptability and flexibility, and cannot cope with leaps and extreme working conditions, resulting in excessive impact during landing, affecting safety and comfort.

[0006] Damping cannot be adjusted in real time: The damping of traditional suspension systems is generally fixed and cannot be adjusted in real time according to the driving environment or vehicle dynamics (such as speed, uneven road surface). Especially during the leap process, the suspension cannot adjust the damping in time to adapt to the sudden impact, resulting in greater vibration during landing.

[0007] Lack of adaptability: Traditional suspension cannot dynamically adjust suspension response according to different driving conditions (such as different terrains, vehicle leaps, etc.). In complex terrain or extreme conditions, fixed damping causes landing shock to fail to be reasonably attenuated, increasing damage to the vehicle. The vibration of the vehicle when jumping or landing may affect the comfort of the occupants and even cause safety hazards.

[0008] Second, electronically controlled suspension. Although it has high adjustability, the existing control algorithm is still not adaptable enough to soft landings. There is a lag phenomenon, and the damping cannot be adjusted in advance according to dynamic changes. The upper limit of the environmental scenario of UTV flying landing is low. The existing electronically controlled suspension has the following defects:

[0009] Lack of advance control: During a leap or jump, the existing control algorithm cannot predict the force condition of each suspension when it lands, resulting in a very "passive" damping adjustment of the suspension during landing. In this rapidly changing state, it is impossible to make instant adjustments, and sudden vibrations and impacts may occur during landing.

[0010] Complexity and instability: The electronically controlled suspension system needs to collect a large amount of sensor data in real time, perform real-time calculations, and make corresponding adjustments to the damping. However, under the flying condition, the advantages and disadvantages of the existing control algorithm are limited by the sensor configuration scheme.

[0011] Although the existing electronically controlled suspension system can adjust the damping under normal driving conditions (for example, to adapt to different road surfaces and vehicle speeds), the suspension control algorithm fails to optimize the leap and landing conditions during the leap. During the bounce and landing moments before the leap, the electronic control system may not be able to fully predict the vehicle's leap height, speed, and landing posture, resulting in untimely and inaccurate damping adjustments, affecting the vehicle's stability during landing. Summary of the invention

[0012] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an all-terrain vehicle (UTV) soft landing control method based on CDC suspension, aiming to solve the two major problems of suspension response lag and large landing impact under the condition of soft landing of the existing electronic control suspension. Its control strategy is to adjust the damping in real time and optimize the UTV landing process by real-time detection of the vehicle's flying posture, body speed, vehicle speed and other dynamic data.

[0013] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for controlling the soft landing of an all-terrain vehicle leap, comprising dividing the leaping action of the all-terrain vehicle into multiple action states, judging the action state of the vehicle by detecting the dynamic data of the current vehicle and allocating corresponding damping control based on the action state to adjust the damping of the suspension.

[0014] The vehicle's multiple action states include uphill state, flying state, and landing state; the damping force of the suspension system is adjusted according to the identified current action state to ensure a smooth leap and soft landing of the vehicle.

[0015] By collecting the vehicle body speed, pitch angle and angular velocity, it is determined whether the vehicle is in an uphill state, and the suspension damping is increased in the uphill state.

[0016] When going uphill, the vehicle body speed is detected and the suspension damping is adjusted and increased according to the vehicle body speed to suppress the vehicle body speed.

[0017] By collecting and calculating the vehicle body speed and acceleration, it is determined whether the vehicle is in a flying state. In the flying state, the suspension damping is quickly reduced to the set value.

[0018] In the flying state, whether the vehicle is in a flying falling state is determined based on the vehicle body speed and body acceleration. When in the flying falling state, the load damping force that each suspension needs to withstand when landing is calculated, and when the vehicle lands, the damping of each suspension is adjusted to the calculated load damping force that the suspension needs to withstand when landing.

[0019] Detect whether the vehicle is in the landing state. In the landing state, check whether the current vehicle has reached the damping action time threshold or whether the vehicle is in a stable state. If so, it will exit with a soft landing. Otherwise, continue to adjust the damping of each suspension to the calculated load damping force that the suspension needs to withstand when it lands.

[0020] When in a flying falling state, the load that each suspension needs to bear when landing is calculated based on the vertical speed of the vehicle body, the pitch angle of the vehicle body, and the tilt angle of the vehicle body.

[0021] The damping action time threshold is calculated based on the vehicle speed and the vertical velocity of the vehicle body collected at the moment of landing.

[0022] The advantages of the present invention are: improving landing stability: by adjusting the suspension damping in real time, the impact force is significantly reduced when the vehicle lands, thereby improving the landing stability.

[0023] Enhanced safety: Reduce the impact on the vehicle body and passengers during landing, reduce damage to the vehicle body structure, and improve the comfort and safety of passengers.

[0024] Improve suspension adaptability: The suspension response can be adjusted in real time according to the actual flying height, speed, landing status, etc., to improve the adaptability of the suspension system.

[0025] Extend the service life of the suspension: As the impact force is effectively absorbed, the probability of the shock absorber touching the limit block and buffer block is reduced. Therefore, the mechanical wear between the suspension components is effectively reduced, the fatigue damage of the material is reduced, the aging of the suspension components is delayed, and the service life of the suspension system is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0027] Figure 1 The present invention is a control flow chart of a method for controlling a flying and soft landing of an all-terrain vehicle. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0029] The present invention provides a UTV flying soft landing control method based on CDC suspension, aiming to solve the two major problems of suspension response lag and large landing impact in the existing electronic control suspension under flying soft landing conditions. Its control strategy is to adjust the damping in real time and optimize the UTV landing process by real-time detection of the vehicle's flying posture, body speed, vehicle speed and other dynamic data.

[0030] The soft landing control method provided by the scheme includes dividing the flying process of the all-terrain vehicle into multiple action states, and then designing different suspension damping adjustment strategies for different action states, so as to meet the soft landing requirements of the all-terrain vehicle when flying.

[0031] In this embodiment, the action states are divided into at least: uphill state, flying state, and landing state.

[0032] The flight state can be further divided into a flight ascending state and a flight descending state.

[0033] Various states can be defined from multiple perspectives, described from the perspective of vehicle body data:

[0034] Uphill state: the vehicle's center of mass speed is upward, and the center of mass acceleration is upward;

[0035] Flight state: The vehicle's center of mass speed is close to 0, and the center of mass acceleration is downward;

[0036] Landing state: the vehicle's center of mass velocity is downward, the center of mass acceleration is downward, and the suspension is in compression.

[0037] Describe from the perspective of body posture:

[0038] Uphill state: the vehicle leaves the ground and moves upward;

[0039] Flight state: the vehicle is off the ground and moving horizontally;

[0040] Landing state: the vehicle has landed.

[0041] Judgment can be made by obtaining relevant parameters through definitions from different angles.

[0042] like Figure 1 As shown, the soft landing control method of the all-terrain vehicle during leaping of the present scheme includes the following steps:

[0043] S1. Determine the state of the vehicle to detect whether the vehicle is in a flying state; the flying state is determined by collecting state data of the vehicle.

[0044] Signal acquisition includes: 6-axis IMU and suspension height sensor, which collect the acceleration and angular velocity of the vehicle in three directions, and then calculate the endpoint velocity of each suspension and the vehicle posture information.

[0045] The corresponding judgment logic of the leap state:

[0046] L1-The absolute value of the vehicle speed is less than the set threshold speed

[0047] L2-the vehicle center of mass acceleration is less than the set threshold acceleration

[0048] L3-The absolute value of the suspension speed is less than the set suspension speed threshold

[0049] If L1 L2 L3 are satisfied at the same time, it is considered as a leap state.

[0050] The above logic must meet the Bounce Time set under this judgment (suppressing the impact of instantaneous interference or abnormal status on the system).

[0051] By identifying the leap state, it is determined whether the current state is in the leap state. If the current state is in the leap state, the process proceeds to step S2;

[0052] S2. The vehicle state is divided into different zones to determine the current state of the vehicle.

[0053] S3, if in state 1: uphill state, then appropriately increase the damping; if in state 2: flying up state, then significantly reduce the damping; if in state 3: flying down state, then calculate the damping force required for each suspension when landing;

[0054] S4, detecting whether the current vehicle is in a landing state, and if so, maintaining the suspension adjustment damping to the calculated damping force required for each suspension landing until the damping action time threshold corresponding to the landing is reached or the vehicle is in a stable state;

[0055] If the landing state reaches the calculated damping force action time threshold or the vehicle is in a stable state, the leap damping control strategy is terminated and the damping control is taken over by other control modules.

[0056] In this solution: the vehicle's speed, posture, and motion state are monitored in real time through IMU (inertial measurement unit) speed sensors, body posture sensors, and other sensors. The damping of the suspension is adjusted in real time using real-time adaptive damping of the body posture. The specific process is as follows:

[0057] Flying soft landing state 1 (uphill state): determine whether the current state is an uphill state based on the vehicle speed, pitch angle and angular velocity. If it is determined to be a flying soft landing state 1, increase the damping appropriately to suppress the vehicle speed based on the vehicle speed.

[0058] Based on the speed, pitch angle, and angular velocity, it is determined whether the vehicle is in an uphill state. The judgment logic includes:

[0059] L1 pitch angle is less than the preset pitch angle threshold;

[0060] L2 The absolute value of the pitch angular velocity is greater than the preset pitch angular velocity threshold;

[0061] When conditions L1 and L2 are satisfied at the same time, the judgment is true, that is, it is judged to be an uphill state.

[0062] The above logic must meet the Bounce Time set under this judgment (suppressing the impact of instantaneous interference or abnormal status on the system).

[0063] According to the vehicle body speed, appropriately increasing the damping to suppress the vehicle body speed means increasing the damping according to the pitch angular velocity and the suspension speed, and increasing the damping based on the damping at the moment before the uphill state. The relationship between the damping and the vehicle speed is obtained by looking up a table, and a comparison relationship table is set in advance. The comparison relationship table needs to be calibrated through the actual vehicle.

[0064] The flying soft landing state 2 (flying ascent state) determines whether the current state is the flying ascent state based on the vehicle body speed and the vehicle body acceleration. If it is determined to be the flying soft landing state 2, the restoring damping is quickly reduced so that the suspension can release the travel as soon as possible to cope with the landing impact.

[0065] The judgment logic for judging the rising state based on speed and acceleration includes:

[0066] L1-body speed is greater than the vehicle speed threshold;

[0067] L2-the vehicle body center of mass acceleration is greater than the center of mass acceleration threshold;

[0068] L3-the absolute value of the suspension speed is less than the suspension speed threshold;

[0069] When conditions L1, L2 and L3 are met at the same time, it is determined to be in the rising state.

[0070] The above logic must meet the Bounce Time set under this judgment (suppressing the impact of instantaneous interference or abnormal status on the system)

[0071] In the flight ascending state, the original damping is quickly reduced and restored. The restoration damping refers to the damping of the shock absorber during the suspension recovery process. The purpose of reducing the restoration damping is to allow the suspension to release the suspension stroke as quickly as possible during the ascending stage, so as to ensure the maximization of the suspension stroke when landing. The original damping refers to the damping before the vehicle is in the flight state or before the start of the flight.

[0072] The flying soft landing state 3 (flying falling state) determines whether the state is in the flying falling state based on the vehicle body speed and vehicle body acceleration.

[0073] The judgment logic for determining the flight falling state based on speed and acceleration includes:

[0074] L1-body speed is less than the threshold

[0075] L2-body center of mass acceleration is less than the threshold

[0076] L3-absolute value of suspension speed is less than the threshold

[0077] When conditions L1 L2 L3 are met at the same time, it is judged to be in the rising state;

[0078] The above logic must meet the Bounce Time set under this judgment (suppressing the impact of instantaneous interference or abnormal status on the system).

[0079] The damping during the falling process begins to prepare for landing. According to the formula F i (x) Calculate the damping when landing. Before landing, follow F i (x) to adjust the damping size.

[0080] Based on the vertical speed of the vehicle body, the pitch angle of the vehicle body, and the tilt angle of the vehicle body, calculate the load that each suspension needs to bear when it lands. The calculation formula is as follows:

[0081]

[0082] F i (x): Damping force of each suspension at the relative position x of the suspension

[0083] m i : Total mass at each suspension

[0084] v CG : The vehicle's center of mass velocity

[0085] ρ: Pitch angular velocity gain coefficient

[0086] σ: Roll angular velocity gain coefficient

[0087] k i : Spring stiffness of each suspension

[0088] x 0 : Initial position of the suspension before landing

[0089] x 1 : Expected compression position of the suspension, determined by the suspension mode

[0090] n: nonlinear index, determines the nonlinear relationship between damping force and displacement, which is determined by the suspension mode. The calculated load damping force F of each suspension i (x), adjust the damping force of each suspension to F in the falling state i (x) The required damping force is calculated in advance based on the posture of the vehicle before landing, and the corresponding damping is adjusted in advance to cope with the fall.

[0091] In the soft landing state 4 (landing state), the damping action time during the soft landing is determined according to the vehicle speed and the vertical speed of the vehicle body.

[0092] Landing status judgment includes:

[0093] L1-Any suspension speed is greater than the threshold

[0094] L2-Body acceleration is greater than the threshold

[0095] When conditions L1 and L2 are met at the same time, the judgment is true, and the vehicle is judged to be in the landing state.

[0096] The above logics must all satisfy the Bounce Time (suppressing the impact of instantaneous interference or abnormal conditions on the system) set under this judgment. Calculating the damping action time based on the vehicle speed and the vertical speed of the vehicle body refers to calculating the damping action time by looking up a table. The preset comparison table can be obtained through test calibration.

[0097] In the soft landing state 5 (steady state), it is detected that the vehicle is in a stable state or the damping action time. The soft landing is exited and the damping control is taken over by other control modules.

[0098] The steady state judgment includes:

[0099] L1- Four suspension speeds are less than the threshold

[0100] L2-Body acceleration is less than the threshold

[0101] L3-The absolute value of the vehicle body pitch and roll angular velocity is less than the threshold

[0102] When conditions L1 L2 L3 are met at the same time, the judgment is true and the system is in a stable state.

[0103] The above logic must meet the Bounce Time set under this judgment (suppressing the impact of instantaneous interference or abnormal status on the system).

[0104] After the calculated damping action time is reached, the soft landing is exited. The damping action start time is triggered after landing, and the end time is determined by the action time obtained by looking up the table based on the vehicle speed at the time of triggering when the vehicle is detected to be in a relatively stable state (body speed and acceleration are less than the threshold). If one of the two is met, the function is exited.

[0105] Through the damping adjustment and control logic in the above leap process, the following technical effects and advantages can be achieved:

[0106] 1. Improve landing stability: By adjusting the suspension damping in real time, the impact force is significantly reduced when the vehicle lands, thereby improving the landing stability.

[0107] 2. Enhanced safety: Reduce the impact on the vehicle body and passengers during landing, reduce damage to the vehicle body structure, and improve the comfort and safety of passengers.

[0108] 3. Improve suspension adaptability: The suspension response can be adjusted in real time according to the actual flying height, speed, landing status, etc., to improve the adaptability of the suspension system.

[0109] 4. Extend the service life of the suspension: As the impact force is effectively absorbed, the probability of the shock absorber touching the limit block and buffer block is reduced. Therefore, the mechanical wear between the suspension components is effectively reduced, the fatigue damage of the material is reduced, the aging of the suspension components is delayed, and the service life of the suspension system is extended.

[0110] In this embodiment, the specific technical details of this solution include:

[0111] 1. Automatic recognition algorithm for soft landing:

[0112] The protection point of the present invention includes an automatic recognition algorithm for the leap state. The vehicle dynamic data is collected in real time through a variety of sensors (such as IMU, acceleration sensor, body posture sensor), and the leap state (take-off, flight, landing) of the vehicle is automatically identified according to the preset algorithm, and the damping force of the suspension system is automatically adjusted to ensure the smooth leap and soft landing of the vehicle.

[0113] 2. Damping force calculation and adjustment algorithm:

[0114] The present invention provides a damping force calculation and adjustment algorithm based on vehicle body posture, acceleration, and leap state judgment. The algorithm accurately calculates the damping force required for different leap states by real-time feedback of vehicle dynamic data, and adjusts it through the suspension system. In particular, the algorithm can dynamically estimate according to the pitch angle, acceleration changes, and wheel load changes, and finely control the damping of the suspension when it lands, ensuring that the optimal damping force adjustment can be achieved in each state.

[0115] 3. Precise transition control of suspension damping force during the leap process:

[0116] The protection point of the present invention also includes precise transition control of the suspension damping force during the leap process. The control method accurately adjusts the transition of the damping force according to the dynamic changes of the vehicle body and the requirements of different leap states to ensure that the vehicle's suspension can always transition smoothly from takeoff, flight to landing, avoiding adverse consequences caused by excessive rebound or instability of posture.

[0117] The soft landing of the leap is based on the adaptive control algorithm to calculate the damping force required for each suspension in real time. The suspension controller collects the signals of various sensors of the vehicle body (including the acceleration of the left front wheel, the acceleration of the right front wheel and the 6-axis IMU) in real time to judge the current leap state (take-off, flight, landing). At the beginning of the flight state, the shock absorber recovery damping is reduced to the minimum. When the vehicle body speed is downward, the recovery damping returns to the normal level, and the flight enters the falling period. The damping required for landing is calculated based on the curb weight, pitch angle, roll angle, vertical speed, pitch angular velocity and roll angular velocity of the vehicle body, so that the damping force required for each suspension of the vehicle before landing is updated in real time. The damping force required for each suspension is adjusted to the calculated load damping force at or before landing.

[0118] After landing, the timing of exiting the soft landing control is determined based on whether the vehicle body is in a stable state or the duration of the damping force.

[0119] All innovations in technical solutions involving multi-state recognition of leaps, damping force adjustment, and prediction of the damping force required for landing are within the scope of protection of the present invention.

[0120] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for controlling a soft landing of an all-terrain vehicle, characterized in that: The method includes dividing the flying action of the all-terrain vehicle into a plurality of action states, determining the action state of the vehicle by detecting the dynamic data of the current vehicle, and allocating corresponding damping control based on the action state to adjust the damping of the suspension.

2. The method for controlling a soft landing of an all-terrain vehicle according to claim 1, characterized in that: The vehicle's multiple action states include uphill state, flying state, and landing state; the damping force of the suspension system is adjusted according to the identified current action state to ensure a smooth leap and soft landing of the vehicle.

3. The method for controlling a soft landing of an all-terrain vehicle according to claim 2, characterized in that: By collecting the vehicle body speed, pitch angle and angular velocity, it is determined whether the vehicle is in an uphill state, and the suspension damping is increased in the uphill state.

4. The method for controlling a soft landing of an all-terrain vehicle according to claim 3, characterized in that: When going uphill, the vehicle body speed is detected and the suspension damping is adjusted and increased according to the vehicle body speed to suppress the vehicle body speed.

5. The method for controlling a soft landing of an all-terrain vehicle according to claim 2, characterized in that: By collecting and calculating the vehicle body speed and acceleration, it is determined whether the vehicle is in a flying state. In the flying state, the suspension damping is quickly reduced to the set value.

6. The method for controlling a soft landing of an all-terrain vehicle according to claim 5, characterized in that: In the flying state, whether the vehicle is in a flying falling state is determined based on the vehicle body speed and body acceleration. When in the flying falling state, the load damping force that each suspension needs to withstand when landing is calculated, and when the vehicle lands, the damping of each suspension is adjusted to the calculated load damping force that the suspension needs to withstand when landing.

7. A method for controlling a soft landing of an all-terrain vehicle according to any one of claims 1 to 6, characterized in that: Detect whether the vehicle is in the landing state. In the landing state, check whether the current vehicle has reached the damping action time threshold or whether the vehicle is in a stable state. If so, it will exit with a soft landing. Otherwise, continue to adjust the damping of each suspension to the calculated load damping force that the suspension needs to withstand when it lands.

8. A method for controlling a soft landing of an all-terrain vehicle according to any one of claims 1 to 6, characterized in that: When in a flying falling state, the load that each suspension needs to bear when landing is calculated based on the vertical speed of the vehicle body, the pitch angle of the vehicle body, and the tilt angle of the vehicle body.

9. The method for controlling a soft landing of an all-terrain vehicle according to claim 7, characterized in that: The damping action time threshold is calculated based on the vehicle speed and the vertical velocity of the vehicle body collected at the moment of landing.

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