Full working condition automatic control method of electric wheel all-terrain vehicle

Abstract

This invention relates to the field of electric drive control technology and discloses an automatic control method for an electric wheeled mountain vehicle under all working conditions. The method includes calculating and fusing the reference vehicle speed and transient slip ratio in pure wheeled mode; upon receiving reversing or uphill commands, constructing a state phase plane, controlling the deployment of auxiliary tracks, adjusting the target duty cycle, and calculating the target cavity pressure to generate normal support force when the slip ratio exceeds the limit, based on the Jacobian mapping relationship; controlling the shock-absorbing wheel system bracket to extend downwards and retract the auxiliary tracks to restore wheeled drive based on the slope crest pitch angle evaluation value; deploying the auxiliary tracks when the downhill trigger condition is met and combining regenerative braking with braking commands to form a composite braking state; calculating the stability margin and outputting an anti-rollover interruption command, or retracting the auxiliary tracks to execute differential drive actions when a steering signal is received. This invention improves the vehicle's traction stability, anti-rollover capability, and steering smoothness through terrain pre-control and electromechanical-hydraulic coordinated energy cascade redistribution.

Description

Technical Field

[0001] This invention relates to the field of electric drive control technology, specifically to an automatic control method for an electric wheeled mountain vehicle under all working conditions. Background Technology

[0002] Electric wheeled mountaineering vehicles have both wheeled and tracked off-road modes and are commonly used in mountainous terrain and complex obstacle courses. When traveling on such terrain, the vehicle needs to frequently switch between wheeled and tracked modes and cope with changes in attitude and load fluctuations caused by terrain undulations.

[0003] When encountering abrupt terrain changes, existing control systems often rely on sensors for passive triggering, resulting in a control response that lags behind the impact of the terrain. When a vehicle collides with an obstacle, the hydraulic mechanism cannot adjust the damping in time to buffer the impact, causing the vehicle body to suffer rigid impact and excessive pitch angle changes, which reduces vehicle ride comfort and exacerbates the load on chassis components.

[0004] Furthermore, when driving on low-traction road sections, the drive wheels are prone to spinning and slipping. Existing traction control strategies mostly suppress slippage by limiting the output torque of the drive motor. While this reduces spinning, it also causes a loss of drive power. The existing control mechanism fails to establish coordinated compensation between actuators and cannot utilize the reduced drive power to enhance the normal support force of the chassis, resulting in insufficient vehicle traction stability.

[0005] When the vehicle is turning or traveling on a side slope, the position of the vehicle's center of gravity changes dynamically. Existing control schemes lack real-time dynamic calculation of the vehicle's stability margin, making it difficult to coordinate the hydraulic system and drive motor to actively prevent rollover when the risk of rollover increases. At the same time, when the vehicle is safely performing a steering action, if the auxiliary track is continuously in contact with the ground, the friction between the track and the ground will cause steering interference, increase steering resistance, and affect the vehicle's motion stability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an automatic control method for electric wheeled mountain bikes under all working conditions. This method solves the problems of rigid impact caused by delayed response to sudden terrain changes, loss of traction due to anti-slip and torque limiting, and steering interference and rollover hazards caused by the lack of multi-mechanism coordination in existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for automatic control of an electric wheeled mountain vehicle under all working conditions, comprising the following steps:

[0009] In pure wheel mode, the longitudinal acceleration and encoder linear velocity are obtained, the reference vehicle speed formula is called to calculate the fused reference vehicle speed, and the transient slip ratio is calculated based on the fused reference vehicle speed.

[0010] Upon receiving a reversing or uphill command, the system acquires the torque change rate and pitch angular velocity to construct a state phase plane and calculates the phase plane characteristic values. Based on the phase plane characteristic values, it controls the auxiliary track deployment to switch to track working condition. The system obtains the target duty cycle based on the transient slip ratio and hydraulic damping formula, and adjusts the proportional hydraulic valve. When the transient slip ratio is greater than the preset slip safety boundary, a torque reduction command is generated. The system calculates the target cavity pressure based on the Jacobian mapping relationship and generates a pressurization command to make the actual cavity pressure converge to the target cavity pressure, thereby generating a normal support force.

[0011] Collect distance signals and vehicle pitch angle to determine the pitch angle evaluation value at the top of the slope, generate a transition request to retract the auxiliary track and restore wheel drive, deploy the auxiliary track and output regenerative braking status when the downhill trigger condition is met, and output braking command based on downhill speed and speed change to enter downhill working condition.

[0012] The vehicle body attitude parameters are collected to calculate the center of gravity projection coordinates to calculate the stability margin. Based on the stability margin, an anti-rollover interruption command is output to maintain a safe support state. The main drive motor is controlled to generate roll suppression torque. When a steering signal is obtained, the auxiliary track is retracted and the differential drive action is executed to enter the steering control state.

[0013] Furthermore, in pure wheeled mode, before the steps of obtaining longitudinal acceleration and encoder linear velocity, calling the reference vehicle speed formula to calculate the fused reference vehicle speed, and calculating the transient slip ratio based on the fused reference vehicle speed, the following initialization setup steps are included:

[0014] After the on-board controller performs power-on initialization, it reads the calibration parameters in the storage unit to establish the reference coordinates. It combines the distance signals collected by the front and rear distance sensors and the mechanical contact rod travel signal collected by the limit switch through a logical OR operation to form a trigger matrix. It obtains the hydraulic cylinder displacement signal collected by the hydraulic cylinder displacement sensor, calculates the auxiliary track reference angle by combining it with the geometric dimensions of the chassis mechanical linkage, and writes it into the reference coordinates. It sends a status polling request to the motor driver and hydraulic valve. When the trigger matrix and reference coordinates are successfully established, and the status of the motor driver and the hydraulic valve are equal to the self-test reference status, it outputs a release parking command to control the auxiliary track hydraulic cylinder to retract the auxiliary track and extend the shock-absorbing wheel system brackets of the front and rear wheels synchronously, so that the electric wheeled mountain vehicle enters the pure wheel mode.

[0015] Furthermore, in pure wheeled mode, the steps of obtaining longitudinal acceleration and encoder linear velocity, calculating the fused reference vehicle speed using the reference vehicle speed formula, and calculating the transient slip ratio based on the fused reference vehicle speed include:

[0016] The initial speed is established by acquiring the longitudinal acceleration collected by the inertial measurement unit and the encoder linear velocity collected by the wheel encoder. Based on the suspension pressure output by the pressure sensor and a preset suspension threshold, a fusion weighting coefficient is derived and smoothed using a low-pass filter. The reference vehicle speed formula is called to calculate the product of the fusion weighting coefficient and the sum of the time integrals of the initial speed and longitudinal acceleration. This product is then added to the product of the difference between the fusion weighting coefficient and the encoder linear velocity to obtain the fusion reference speed. The fusion reference speed is compared with the drive-side calculated linear velocity fed back from the main drive motor. The larger value is selected as the reference speed. When the reference speed is greater than zero, the difference between the drive-side calculated linear velocity and the fusion reference speed is divided by the reference speed to calculate the transient slip ratio, which is then written to the data bus. The transient slip ratio characterizes the slip state of the main track.

[0017] Furthermore, upon receiving a reversing or uphill command, the steps of acquiring the torque change rate and pitch angular velocity to construct a state phase plane and calculating phase plane characteristic values, and controlling the auxiliary track deployment to switch to tracked operation based on the phase plane characteristic values, include:

[0018] Upon receiving a reversing or uphill command, the system acquires the torque change rate corresponding to the torques of the left and right main drive motors, as well as the pitch angular velocity output by the inertial measurement unit, and uses these as the horizontal and vertical axes to construct the state phase planes. It then calls the step recognition formula to calculate the square of the product of the preset first phase plane normalization coefficient and the torque change rate, adds the square of the product of the preset second phase plane normalization coefficient and the pitch angular velocity, and takes the square root of the sum to calculate the phase plane characteristic value. When the phase plane characteristic value is greater than a preset trigger threshold, a step recognition result is generated, and an advance trigger command is issued. Based on the advance trigger command, an unfolding command is output to the hydraulic folding device, causing the auxiliary track to unfold and output the auxiliary track unfolded state. Simultaneously, a switching command is output to the motor driver, controlling the left and right main drive motors to enter a low-speed torque state, driving the main track to provide basic traction, thus switching to track operation.

[0019] Furthermore, the steps for adjusting the proportional hydraulic valve by obtaining the target duty cycle based on the transient slip ratio and hydraulic damping formula include:

[0020] The transient slip ratio, vehicle pitch acceleration, and torque reduction command generated in the previous control cycle are input into the adaptive filter. Frequency domain matching processing is performed based on the valve body response time constant, and the filtered slip ratio, filtered torque reduction, and filtered angular acceleration are output. The hydraulic cylinder displacement signal at the current sampling moment and the hydraulic cylinder displacement signal at the previous adjacent sampling moment are extracted and differentially calculated based on the time axis to obtain the displacement change. The trajectory vector in the state phase plane is extracted, and its geometric phase angle and amplitude are transformed by piecewise linear interpolation using an algebraic mapping function to calculate the basic duty cycle. The hydraulic damping formula is called, and the product of the preset slip ratio adjustment gain and the filtered slip ratio, the product of the preset angular acceleration adjustment gain and the filtered angular acceleration, and the product of the preset displacement adjustment gain and the displacement change are successively subtracted from the basic duty cycle to calculate the target duty cycle. The proportional hydraulic valve obtains the target duty cycle, adjusts the opening of the hydraulic valve, adjusts the position of the auxiliary track hydraulic cylinder to generate the extension state, and outputs the compliant control state.

[0021] Furthermore, when the transient slip ratio exceeds a preset slip safety boundary, a torque reduction command is generated. The target cavity pressure is calculated using the Jacobian mapping relationship, and a pressurization command is generated to converge the actual cavity pressure towards the target cavity pressure, thus producing a normal support force. The steps include:

[0022] When the transient slip ratio exceeds the preset slip safety boundary, the traction control algorithm generates a limiting torque command and calculates the corresponding torque reduction command. It acquires the track deployment angle and vehicle pitch angle derived from the hydraulic cylinder displacement signal, and uses the Jacobian function to calculate the Jacobian mapping relationship between the auxiliary track hydraulic cylinder and the chassis components. When the absolute value of the product of the drive wheel radius, cross-sectional area, and the Jacobian mapping relationship exceeds the set boundary reference amplitude, it uses the hydraulic compensation formula to divide the filtered torque reduction by the aforementioned absolute value of the product, adds the steady-state cavity pressure, and calculates the target cavity pressure. It acquires the actual cavity pressure collected by the hydraulic cavity pressure sensor, calculates the cavity pressure error between the target cavity pressure and the actual cavity pressure, and inputs it into the cavity pressure closed-loop control algorithm to generate a boost command, driving the actual cavity pressure to converge towards the target cavity pressure to form the adjusted cavity pressure. Under the thrust of the adjusted cavity pressure, the auxiliary track generates a normal support force that balances the normal support force compensation, and performs cascaded weight distribution.

[0023] Furthermore, the steps of acquiring distance signals and vehicle pitch angle to determine the hill crest pitch angle assessment value, in order to generate a transition request to retract the auxiliary tracks and restore wheel drive, include:

[0024] By combining the rear distance signal collected by the rear ranging sensor as a distance signal and the vehicle pitch angle collected by the inertial measurement unit, the pitch angle evaluation value at the top of the slope is determined. When the pitch angle evaluation value at the top of the slope is less than or equal to the preset safety setting value, a transition request is generated. Based on the transition request and the rear distance signal, when it is determined that the rear wheel has reached the top of the slope, a command is first sent to the wheel system support mechanism to drive the shock-absorbing wheel system support of the corresponding rear wheel to extend downward to support the ground. The left main drive motor and the right main drive motor continue to drive the main track and auxiliary track to continue to travel until the front distance signal collected by the front ranging sensor determines that the front wheel has reached the top of the slope. Then, a command is sent to the wheel system support mechanism to drive the shock-absorbing wheel system support of the corresponding front wheel to extend downward to support the ground to output the support extension state.

[0025] After confirming full wheel load, the output action command controls the auxiliary track hydraulic cylinder to retract and outputs the hydraulic cylinder retraction state; the combined limit sensor output closure signal and hydraulic cylinder displacement signal generate real-time status; when the real-time status is equal to the preset stroke threshold and the closure signal is valid, the position confirmation command is output and physical position confirmation is established; upon receiving the position confirmation command, the current track traction command is smoothly reduced to zero and the power disconnection state is output to the data bus, and the wheel drive control logic is activated to restore wheel drive.

[0026] Furthermore, when the downhill triggering conditions are met, the auxiliary tracks are deployed and regenerative braking is output. Combined with the downhill speed and speed change, a braking command is output. The steps to enter the downhill working condition include:

[0027] When the vehicle pitch angle is less than zero degrees and the forward distance signal collected by the front ranging sensor as a distance signal is less than the preset variable amplitude safety distance, and the mechanical contact rod stroke signal in the trigger matrix is ​​out of the trigger state, it is determined that the downhill trigger condition is met and a downhill trigger command is generated, entering the downhill working condition; according to the downhill trigger command, an unfolding command is output to the hydraulic folding device to unfold the auxiliary tracks, and the left main drive motor and the right main drive motor are instructed to output regenerative braking state; the downhill speed at the current sampling time is differentiated from the downhill speed at the previous adjacent sampling time to calculate the speed change; when the downhill speed is greater than the preset speed safety boundary and the speed change is greater than the preset step threshold, a braking command is output to the mechanical disc brake to execute the clamping action, forming a compound braking state together with the regenerative braking state;

[0028] When the downhill driving control is completed and the vehicle reaches the bottom of the slope, the vehicle determines that the front wheel has reached the flat ground at the bottom of the slope based on the forward distance signal and the vehicle's pitch angle. At this time, the vehicle drives the shock-absorbing wheel system bracket of the corresponding front wheel to extend downward to support the ground. The vehicle controls the left main drive motor and the right main drive motor to release the compound braking state and drive the main track to continue traveling until the vehicle determines that the rear wheel has reached the flat ground at the bottom of the slope based on the rear distance signal. At this time, the vehicle drives the shock-absorbing wheel system bracket of the corresponding rear wheel to extend downward to support the ground. After confirming that the entire wheel is under load, the vehicle controls the hydraulic folding device to retract the auxiliary track and restore the vehicle to a pure wheel state.

[0029] Furthermore, the steps for collecting vehicle attitude parameters and calculating the center of gravity projection coordinates to calculate the stability margin include:

[0030] The vehicle's pitch angle, roll angle, and roll angular velocity are collected as vehicle attitude parameters. These are combined with the track center distance, front and rear track wheel center distance, and initial center of gravity height as structural parameters to form attitude and structural parameters. Homogeneous coordinate projection transformation is invoked to construct a spatial homogeneous rotation matrix, and a three-dimensional translation matrix is ​​constructed using the initial center of gravity height for calculation. The resulting center of gravity projection coordinates are then calculated and output. Based on the topology of the extreme vertices of the actual ground contact area of ​​the electric wheeled mountain climbing vehicle, polygons are calculated as the boundaries of the supporting polygons. Geometric distance calculation is invoked to solve for the distances from the center of gravity projection coordinates to each side segment of the supporting polygon boundary, and the current stability margin is calculated and output.

[0031] Furthermore, the steps of maintaining a safe support state by outputting an anti-rollover interruption command based on the stability margin, controlling the main drive motor to generate roll suppression torque, retracting the auxiliary tracks when a steering signal is received, and executing differential drive action to enter the steering control state include:

[0032] Within a preset hysteresis filter range, the stability margin is compared with the lower limit of the distance in the preset safety setting. When the stability margin falls below the lower limit of the distance, an anti-rollover interruption command is output. Based on the anti-rollover interruption command, a pressure holding and limiting command is output to lock the hydraulic flow channel, so that the auxiliary track hydraulic cylinder maintains a safe support state. Based on the anti-rollover interruption command, a roll suppression differential command is output to the left main drive motor and the right main drive motor to execute asymmetrical torque output, forming a roll suppression torque. When the vehicle pitch angle and the stability margin are both within the preset safety setting range, and the steering signal output by the steering input device is obtained, the real-time vehicle pitch angle is compared with a preset severe slope angle threshold.

[0033] When the vehicle pitch angle is less than the severe slope angle threshold, a folding intervention command is output to fold the auxiliary track, and the differential control algorithm generates a steering differential command based on the steering signal to execute the differential drive action, thus entering the steering control state;

[0034] When the vehicle body pitch angle is greater than or equal to the severe slope angle threshold, the folding intervention command is blocked, so that the auxiliary track remains in an unfolded, grounded, unfolded state. The differential control algorithm generates a steering differential command based on the steering signal, and controls the left main drive motor and the right main drive motor to drive the main track to perform in-situ differential drive action.

[0035] This invention provides a fully automated control method for an electric wheeled mountain vehicle under all working conditions. It has the following beneficial effects:

[0036] 1. This invention constructs a state phase plane by acquiring the motor torque change rate and the vehicle pitch angular velocity. Before a physical collision occurs, the phase plane characteristic value is calculated and an advance trigger command is issued. This control logic overcomes the response hysteresis defect of traditional discrete sensors. By calculating the target duty cycle in advance and adjusting the proportional hydraulic valve, adaptive damping buffering is achieved when the vehicle faces sudden terrain impacts, reducing vehicle pitch angle overshoot and structural load.

[0037] 2. This invention limits the traction torque when the drive wheel slips by comparing the transient slip ratio with the slip safety boundary. It also converts the torque reduction into the target chamber pressure of the auxiliary track hydraulic cylinder by combining the Jacobian mapping relationship. Through closed-loop guidance of hydraulic flow channel pressurization, the output power of the main drive motor side, which is limited by suppressing idling, is converted into the normal support force of the chassis on the ground, thereby improving the traction stability of the vehicle on low-traction road sections.

[0038] 3. This invention collects vehicle body attitude parameters and structural parameters, and uses homogeneous coordinate projection transformation to solve the center of gravity projection coordinates and the boundary of the supporting polygon, thereby calculating the stability margin. When the stability margin is less than the safety set value, the auxiliary track hydraulic cylinder is controlled to lock the oil circuit to maintain the support state, and the main drive motor generates roll suppression torque to intervene in preventing rollover. When a steering signal is received within the safe attitude range, the auxiliary track is actively retracted, eliminating steering friction interference and improving the vehicle's anti-rollover ability and steering smoothness. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the automatic control system architecture for an electric wheeled mountain vehicle under all working conditions according to the present invention;

[0040] Figure 2 This is a flowchart of an automatic control method for an electric wheeled mountain vehicle under all working conditions according to the present invention;

[0041] Figure 3 This is a flowchart of the initialization calibration and flat-road multi-source fusion cruise control of the present invention;

[0042] Figure 4 This is a flowchart of the advanced control of complex terrain and electromechanical-hydraulic coordinated adaptive adjustment of the present invention;

[0043] Figure 5 This is a flowchart of the combined smooth transition at the top of the slope and the smooth flow control of the downhill slope according to the present invention;

[0044] Figure 6 This is a flowchart of the three-dimensional anti-rollover safety intervention and dynamic folding steering of the present invention;

[0045] Figure 7 This is a curve comparing the vehicle pitch angle under conventional control and control of the present invention.

[0046] Figure 8 This is a comparison diagram of the cascaded weight distribution effect of the drive wheel slip ratio and normal support force according to the present invention. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Please see the appendix Figure 1 This invention provides an automatic control system for an electric wheeled mountaineering vehicle under all working conditions. This system is installed in the onboard controller of the electric wheeled mountaineering vehicle and is used to control the vehicle.

[0049] The electric wheeled mountaineering vehicle includes a frame assembly, a semi-reclining seat, front wheels, rear wheels, main tracks, auxiliary tracks, a power drive mechanism (including a left main drive motor, a right main drive motor, and a dual-channel motor driver; the left and right main drive motors drive the main tracks), a hydraulic folding device (including auxiliary track hydraulic cylinders, proportional hydraulic valves, a hydraulic pump assembly, a hydraulic tank, a two-way hydraulic lock, a two-way balance valve, and a fluid accumulator), a wheel system support mechanism (including a shock-absorbing wheel system support), a mechanical disc brake equipped with a wire-controlled brake actuator, an electromagnetic parking module, and an onboard controller.

[0050] The chassis assembly is equipped with a front distance sensor, a rear distance sensor, and a limit switch with a mechanical contact rod; the auxiliary track hydraulic cylinder is equipped with a hydraulic cylinder displacement sensor and a hydraulic chamber pressure sensor; the wheel system support mechanism is equipped with a pressure sensor and a limit sensor; the chassis assembly is equipped with an inertial measurement unit; the axles of the electric wheeled mountain car are equipped with wheel encoders; the control panel of the electric wheeled mountain car is equipped with a steering input device.

[0051] The system includes a cruise calibration module, a terrain pre-control module, a transition smooth driving module, and an anti-rollover turning module.

[0052] The cruise calibration module is used to read calibration parameters and establish reference coordinates after the vehicle controller is powered on. It combines the acquired distance signal with the mechanical contact rod stroke signal into a trigger matrix and calculates the auxiliary track reference angle by combining the hydraulic cylinder displacement signal. When the state meets the self-test reference state, it outputs a parking release command to control the auxiliary track hydraulic cylinder to retract the auxiliary track and extend the shock-absorbing wheel system bracket downward, so that the electric wheeled mountain vehicle enters the pure wheel state.

[0053] The initial speed is further determined by combining longitudinal acceleration and encoder linear velocity collected by wheel encoders. Based on suspension pressure and preset suspension threshold, a fusion weighting coefficient is output through a low-pass filter. Then, the fusion reference speed is calculated by calling the reference vehicle speed formula. The reference speed is determined by combining the linear velocity calculated on the drive side to calculate the transient slip ratio. This is then written into the data bus to form subsequent control data.

[0054] The terrain pre-control module, upon receiving a reversing or uphill command, acquires the torque change rate and pitch angular velocity to construct a state phase plane, and calls the step recognition formula to calculate the phase plane feature value. When the phase plane feature value is greater than a preset trigger threshold, it generates a step recognition result and issues an advance trigger command. Based on this advance trigger command, it controls the auxiliary track deployment, outputs the auxiliary track deployment state, and causes the left and right main drive motors to enter a low-speed, high-torque state to switch to track operation. The adaptive filter performs frequency domain matching processing on the transient slip rate, vehicle pitch angular acceleration, and torque reduction command from the previous control cycle, outputting the filtered slip rate, filtered torque reduction, and filtered vehicle pitch angular acceleration.

[0055] The onboard controller calculates the displacement change and uses an algebraic mapping function to calculate the basic duty cycle. It then calls the hydraulic damping formula to obtain the target duty cycle, which is adjusted by a proportional hydraulic valve to form a compliant control state. When the transient slip ratio exceeds the preset slip safety boundary, the traction control algorithm generates a torque reduction command. Combining the Jacobian mapping relationship, it calls the hydraulic compensation formula to calculate the target cavity pressure. The cavity pressure closed-loop control algorithm generates a pressure boosting command to make the actual cavity pressure converge to the target cavity pressure, forming the adjusted cavity pressure. This allows the auxiliary track to generate a normal support force that balances the normal support force compensation under the hydraulic thrust, thus completing the cascaded weight distribution.

[0056] The transition smoothing module is used to determine the hill crest pitch angle assessment value based on the rear distance signal and the vehicle pitch angle. When it is less than or equal to the safety set value, it generates a transition request, controls the auxiliary track hydraulic cylinder to retract, outputs the hydraulic cylinder retraction state, and controls the wheel system support mechanism to drive the shock-absorbing wheel system support to extend downward to output the support extension state. It combines the closing signal and the hydraulic cylinder displacement signal to generate a real-time status, and establishes physical positioning confirmation when the stroke threshold is met. It smoothly returns the current track traction command to zero, outputs the power disconnect state, and enables the wheel drive control logic to enter the wheel drive state.

[0057] Under wheel drive, the system combines forward distance signals, vehicle pitch angle, and trigger matrix to determine downhill trigger conditions. When these conditions are met, the system controls the hydraulic folding device to unfold the auxiliary tracks, putting them into a pre-deployed state facing the slope. The system also causes the left and right main drive motors to output regenerative braking. By calculating the downhill speed and speed change, the system outputs braking commands to the mechanical disc brakes when the speed exceeds the limit. The control line controls the actuator to perform a clamping action, which, together with the regenerative braking state, forms a compound braking state to complete the downhill smooth travel control.

[0058] The anti-rollover steering module collects the vehicle's pitch angle, roll angle, and roll velocity. These parameters, combined with the track center distance, the front and rear track wheel center distance, and the initial center of gravity height, form attitude and structural parameters. It then uses homogeneous coordinate projection transformation to calculate the center of gravity projection coordinates, solves for the support polygon boundary, and outputs the stability margin. When the stability margin is less than the safety setpoint, it outputs an anti-rollover interruption command to maintain the auxiliary track hydraulic cylinder in a safe support state and controls the main drive motor to generate roll suppression torque according to the roll suppression differential command. When all parameters are safe and a steering signal is detected, it outputs a folding intervention command to fold the auxiliary track. The differential control algorithm generates a steering differential command to execute the differential drive action and enter the steering control state.

[0059] See appendix Figure 2 The present invention also provides an automatic control method for an electric wheeled mountaineering vehicle under all working conditions, applied to the above-mentioned automatic control system for an electric wheeled mountaineering vehicle under all working conditions, comprising the following steps:

[0060] S1, Initialization Calibration and Multi-Source Fusion Cruise Control on Flat Road. After the onboard controller is powered on, the cruise calibration module reads calibration parameters to establish reference coordinates, combines the acquired distance signal and mechanical lever travel signal into a trigger matrix, and calculates the auxiliary track reference angle based on the hydraulic cylinder displacement signal. When the status meets the self-test reference state, the cruise calibration module outputs a release parking command to control the auxiliary track hydraulic cylinder to retract the auxiliary track and extend the shock-absorbing wheel system support downwards, putting the electric wheeled mountain vehicle into pure wheel mode.

[0061] The trigger matrix contains a two-row, two-column Boolean matrix. The first row corresponds to the state of the front and rear ranging sensors, respectively, and the second row corresponds to the state of the two limit switches. When the signal of the corresponding sensor is valid, its corresponding matrix element is set to 1, otherwise it is set to 0. The logical OR operation is to perform a parallel logical AND calculation on the Boolean values ​​of the aforementioned rows.

[0062] The cruise calibration module further combines longitudinal acceleration and encoder linear velocity to establish the initial speed, and outputs fusion weighting coefficients through a low-pass filter based on suspension pressure and a preset suspension threshold. The cruise calibration module calls the reference vehicle speed formula to calculate the fusion reference vehicle speed, and combines it with the linear velocity calculated on the drive side to determine the base speed to calculate the transient slip ratio, which is then written into the data bus to form subsequent control data.

[0063] S2 features advanced terrain control and electromechanical-hydraulic adaptive adjustment. Upon receiving a reversing or uphill command, the terrain control module acquires the torque change rate and pitch angular velocity to construct a state phase plane, and calculates the phase plane characteristic value using a step recognition formula. When the phase plane characteristic value exceeds a preset trigger threshold, the terrain control module generates a step recognition result, controls the auxiliary track deployment, outputs the auxiliary track deployment status, and causes the main drive motor to enter a low-speed torque state to switch to track operation.

[0064] The terrain pre-control module performs frequency domain matching processing on transient slip rate, vehicle pitch acceleration, and torque reduction commands through an adaptive filter, outputting filtered slip rate, filtered torque reduction, and filtered angular acceleration. The onboard controller calculates the displacement change and uses an algebraic mapping function to calculate the base duty cycle, calls the hydraulic damping formula to obtain the target duty cycle, and adjusts it by a proportional hydraulic valve to form a compliant control state. When the transient slip rate is greater than the preset slip safety boundary, the traction control algorithm in the terrain pre-control module generates a torque reduction command, calls the hydraulic compensation formula based on the Jacobian mapping relationship to calculate the target cavity pressure, and the cavity pressure closed-loop control algorithm generates a pressure boosting command to converge the actual cavity pressure to the target cavity pressure to form a pressure-adjusted cavity pressure. This causes the auxiliary track to generate a normal support force that balances the normal support force compensation under the action of hydraulic thrust, thus completing the cascaded weight distribution.

[0065] S3, Slope crest smooth transition and downhill combined smooth travel control. The smooth transition module determines the slope crest pitch angle assessment value based on the rear distance signal and the vehicle pitch angle. When it is less than or equal to the safety set value, it generates a transition request, controls the auxiliary track hydraulic cylinder to retract, outputs the hydraulic cylinder retraction state, and controls the wheel system support mechanism to sink and outputs the support extension state. The smooth transition module combines the closing signal and the hydraulic cylinder displacement signal to generate a real-time status, and completes the physical positioning confirmation when the stroke threshold is met.

[0066] The transition smoothing module smoothly returns the track traction command to zero and disconnects the power output, then activates the wheel drive control logic to enter wheel drive mode. Under wheel drive, it combines the forward distance signal, vehicle pitch angle, and trigger matrix to determine the downhill trigger conditions. When these conditions are met, it controls the hydraulic folding device to unfold the auxiliary tracks and causes the main drive motor to output regenerative braking. By calculating the downhill speed and speed change, it outputs a braking command to the mechanical disc brake to perform a clamping action when the limit is exceeded. Together with the regenerative braking state, it forms a compound braking state to complete the downhill smoothing control.

[0067] S4, 3D anti-rollover safety intervention and dynamic folding steering. The anti-rollover steering module collects the vehicle's pitch angle, roll angle, and roll velocity, and combines them with the track center distance, the front and rear track wheel center distance, and the initial center of gravity height to form attitude and structural parameters. It calls the homogeneous coordinate projection transformation to calculate the center of gravity projection coordinates, solves the support polygon boundary, and outputs the stability margin.

[0068] When the stability margin is less than the safety set value, the anti-rollover steering module outputs an anti-rollover interruption command to keep the auxiliary track hydraulic cylinder in a safe support state and controls the main drive motor to generate roll suppression torque according to the roll suppression differential command. When all parameters are within the safe range and a steering signal is detected, the anti-rollover steering module outputs a folding intervention command to fold the auxiliary track, and the differential control algorithm generates a steering differential command to execute the differential drive action to enter the steering control state.

[0069] See appendix Figure 3 In step S1 of this embodiment, the cruise calibration module is responsible for performing the technical actions of the initialization calibration and flat road multi-source fusion cruise control phase.

[0070] S101, after the vehicle controller is powered on, the cruise calibration module controls the vehicle controller to read the calibration parameters in the storage unit. The calibration parameters include the preset self-test reference state, the initially preset fusion weight coefficient, the preset first phase plane normalization coefficient, the preset second phase plane normalization coefficient, and the preset trigger threshold. The preset self-test reference state is a communication bus no-abnormality status flag bit that is predetermined based on the communication level characteristics of the motor driver and hydraulic valve under normal operating voltage and no fault code state. The initially preset fusion weight coefficient is set according to the default confidence level when the system starts, and its value ranges from 0.3 to 0.7, thereby establishing the reference coordinates.

[0071] Furthermore, the cruise calibration module controls the front and rear ranging sensors to acquire and output distance signals, while simultaneously controlling the limit switch to acquire and output the mechanical contact rod travel signal generated by the mechanical contact rod's movement. The onboard controller acquires the distance signal and the mechanical contact rod travel signal, and combines them into a trigger matrix through logical OR operations, thereby establishing input redundancy to achieve physical redundancy triggering through mechanical contacts when the non-contact sensors fail. The process of calculating distance based on the pulse emission and echo time difference of the ranging sensors can be implemented using standard time-of-flight ranging principles by those skilled in the art; its underlying driving and ranging calculation are well-known technologies in the field and will not be elaborated upon here.

[0072] The cruise calibration module collects the displacement state of the auxiliary track hydraulic cylinder through the hydraulic cylinder displacement sensor and outputs the hydraulic cylinder displacement signal. The vehicle controller obtains the hydraulic cylinder displacement signal and calculates the auxiliary track reference angle by combining it with the geometric dimensions of the chassis mechanical linkage. Then, the auxiliary track reference angle is written into the reference coordinate.

[0073] The vehicle controller sends a status polling request to the motor driver to obtain and output the motor driver status, and sends a status polling request to the hydraulic valve to obtain and output the hydraulic valve status. When the trigger matrix and reference coordinates are successfully established and the motor driver status and hydraulic valve status both meet the self-test reference status, the cruise calibration module outputs a release parking command to the electromagnetic parking module.

[0074] S102, the vehicle controller outputs a track retraction drive command to the hydraulic folding device according to the release parking command. The hydraulic folding device drives the auxiliary track hydraulic cylinder to retract the auxiliary track according to the track retraction drive command and generates a driving preparation state.

[0075] In the driving preparation state, the on-board controller outputs a wheel extension drive command to the wheel system support mechanism. The wheel system support mechanism extends the shock-absorbing wheel system support downward according to the wheel system extension drive command (the shock-absorbing wheel system support of the front wheel extends downward synchronously with the shock-absorbing wheel system support of the rear wheel), so that the electric wheeled mountain vehicle enters a pure wheel state. At this time, the vehicle load is borne by the wheels and the auxiliary track is kept off the ground.

[0076] In pure wheeled mode, the electric wheeled mountain scooter uses an inertial measurement unit to collect and output longitudinal acceleration, and wheel encoders to collect and output encoder linear velocity. The onboard controller reads the encoder linear velocity at the initial moment of power-on to establish the initial speed.

[0077] Before using the reference vehicle speed formula to calculate the vehicle speed, its core physical principle lies in using complementary filters to overcome the limitations of a single sensor. Since the inertial measurement unit has a high dynamic response capability in a short time, it is prone to cumulative drift error under long-term integration. The wheel encoder can accurately convert the physical linear velocity when it is not slipping, but the signal will be distorted when the wheel is suspended or slipping. The control system dynamically adjusts the weight of the two in the integrated navigation by introducing pressure sensors to monitor the load status of the wheels in real time.

[0078] In the actual control chain, the pressure sensor collects the load at the wheel system support mechanism and outputs the suspension pressure. The cruise calibration module reads the preset suspension threshold from the storage unit. The preset suspension threshold is set based on the reference pressure caused by the inherent weight of the shock absorber wheel system support and the spring preload when the vehicle is unloaded, and its value ranges from 150N to 300N. The on-board controller re-derives the initially preset fusion weight coefficient based on the suspension pressure. When the suspension pressure is less than the preset suspension threshold, it indicates that the wheel is off the ground or lacks traction. The on-board controller inputs the derived value into a low-pass filter, which smoothly outputs a fusion weight coefficient with longitudinal acceleration as the main reference. At this time, the value of the fusion weight coefficient tends to be 1. When the suspension pressure is greater than or equal to the preset suspension threshold, it indicates that the wheel is under normal load. The on-board controller inputs the derived value into a low-pass filter, which smoothly outputs a fusion weight coefficient with encoder linear velocity as the main reference. At this time, the value of the fusion weight coefficient tends to be 0.

[0079] The cruise calibration module obtains the fusion weighting coefficients, calls the reference vehicle speed formula to perform fusion calculations on the longitudinal acceleration, initial velocity, and encoder linear velocity, and calculates the fused reference vehicle speed.

[0080] ;

[0081] In the formula: To integrate reference vehicle speed; For fusion weighting coefficients; The initial velocity; The integral symbol is used. It is longitudinal acceleration; The time differential term; This refers to the encoder linear velocity; Represents time.

[0082] S103, the main drive motor runs and feeds back the calculated linear velocity on the drive side. The on-board controller obtains the calculated linear velocity on the drive side and reads the fused reference vehicle speed from the data bus.

[0083] The cruise calibration module compares the fusion reference vehicle speed with the drive-side calculated linear speed. When the drive-side calculated linear speed is greater than the fusion reference vehicle speed, the drive-side calculated linear speed is selected as the reference speed. When the drive-side calculated linear speed is less than or equal to the fusion reference vehicle speed, the fusion reference vehicle speed is selected as the reference speed.

[0084] To avoid a calculation dead zone when the vehicle is stationary, the onboard controller performs boundary judgment on the amplitude of the reference speed. When the reference speed is greater than 0, the difference between the calculated linear velocity on the drive side and the fused reference vehicle speed is divided by the reference speed to calculate the transient slip ratio. When the reference speed is equal to 0, the transient slip ratio is directly set to 0. The transient slip ratio is physically used to characterize the relative slip between the drive wheel and the contact surface. The onboard controller writes the transient slip ratio into the data bus to form subsequent control data.

[0085] See appendix Figure 4 In step S2 of this embodiment, the terrain pre-control module is responsible for specifically executing the technical actions of the advanced pre-control of complex terrain and the electromechanical-hydraulic coordinated adaptive adjustment stage.

[0086] In obstacle crossing or reversing situations, traditional non-contact sensors or mechanical contacts typically only generate a posteriori discrete trigger signal after the vehicle has already made physical contact, which cannot provide sufficient response time for the nonlinear and drastic hydraulic damping adjustment system. Therefore, this invention constructs a multi-dimensional state space trajectory that includes transmission load and attitude change rate, and uses a feedforward active recognition mechanism to accurately predict the impact energy caused by terrain changes before the vehicle fully collides with the step, thereby achieving active coordinated adjustment between the power source and the hydraulic actuator.

[0087] S201, when the terrain pre-control module receives a reversing command or an uphill command, it obtains the torque change rate of the main drive motor and the pitch angular velocity output by the inertial measurement unit, and uses the torque change rate and pitch angular velocity as the horizontal and vertical axes to construct the state phase plane.

[0088] The vehicle controller reads the preset first phase plane normalization coefficient, the preset second phase plane normalization coefficient, and the preset trigger threshold from the storage unit;

[0089] The preset first phase plane normalization coefficient and the preset second phase plane normalization coefficient are dimension harmonic coefficients predetermined based on the ratio between the rated torque change rate range of the main drive motor and the maximum dynamic range of the vehicle pitch angular velocity. The preset trigger threshold is a characteristic value determined based on the critical impact energy generated when the electric wheeled mountain vehicle hits a preset height step at standard cruising speed, and its value ranges from 1.5 to 3.0.

[0090] The terrain pre-control module extracts the torque change rate and pitch angular velocity from the state phase plane, calls the step recognition formula to process the torque change rate, pitch angular velocity, and the normalization coefficients of the first and second phase planes, and calculates the phase plane feature value characterizing the magnitude of the trajectory vector in the state phase plane:

[0091] ;

[0092] In the formula: These are the eigenvalues ​​of the phase plane; This is the symbol for the square root. The normalization coefficient for the first phase plane; This represents the rate of change of torque. Main motor torque; The normalization coefficient for the second phase plane; The pitch rate of the vehicle body.

[0093] The onboard controller compares the calculated phase plane feature value with a preset trigger threshold. When the phase plane feature value is greater than the preset trigger threshold, a step recognition result is generated, and an unfolding command is output to the hydraulic folding device, while a switching command is output to the motor driver. The onboard controller compares the calculated phase plane feature value with a preset trigger threshold. When the phase plane feature value is greater than the preset trigger threshold, a step recognition result is generated, and the terrain pre-control module issues an advance triggering command. Based on the advance triggering command, an unfolding command is output to the hydraulic folding device, while a switching command is output to the motor driver. The hydraulic folding device drives the auxiliary track hydraulic cylinder to push open according to the unfolding command, so that the auxiliary track outputs the auxiliary track unfolding state to cope with heavy load impacts. The motor driver controls the left main drive motor and the right main drive motor to enter a low-speed, high-torque state according to the switching command, driving the main track to provide basic traction and controlling the whole vehicle to switch to tracked operation.

[0094] In S202, under the conditions of auxiliary track deployment and low-speed torque, the terrain pre-control module reads the transient slip rate, vehicle pitch acceleration, and torque reduction command written to the data bus from the data bus in step S203 of the previous control cycle; wherein the torque reduction command is preset to zero in the initial control cycle; the vehicle pitch acceleration is synchronously calculated by the inertial measurement unit when collecting pitch velocity and written to the data bus.

[0095] The vehicle controller inputs the transient slip ratio, torque reduction command, and vehicle pitch acceleration into the adaptive filter. The adaptive filter sets the valve body response time constant according to the hydraulic valve state and performs frequency domain matching processing on the input data according to the valve body response time constant. After filtering out high-frequency vibration noise from the structure, it outputs the filtered slip ratio, filtered torque reduction, and filtered angular acceleration.

[0096] Furthermore, the terrain pre-control module acquires the hydraulic cylinder displacement signal at the current sampling moment output by the hydraulic cylinder displacement sensor. It then performs a difference calculation based on the time axis difference between the current sampling moment's hydraulic cylinder displacement signal and the hydraulic cylinder displacement signal at the previous adjacent sampling moment to obtain the displacement change. Simultaneously, the vehicle controller extracts the trajectory vector in the state phase plane and calls an algebraic mapping function to calculate the basic duty cycle. The algebraic mapping function employs a piecewise linear interpolation mapping mechanism to convert the geometric phase angle and amplitude of the trajectory vector into the static duty cycle of the pulse width modulation signal. Specifically, the piecewise linear interpolation mapping mechanism is implemented as follows: multiple sets of two-dimensional lookup tables corresponding to different geometric phase angles (ranging from 0° to 360°) and amplitudes are pre-established. After inputting the phase plane trajectory vector, the basic duty cycle of the target pulse width modulation signal is calculated through linear interpolation, and the output basic duty cycle is subjected to amplitude limiting saturation processing from 0% to 100%.

[0097] The onboard controller reads preset slip ratio adjustment gain, preset angular acceleration adjustment gain, and preset displacement adjustment gain from the storage unit. These adjustment gains are feedback coefficients determined based on the inherent stiffness of the hydraulic piping system and the desired fluid damping coefficient set for the chassis assembly. The onboard controller then uses the hydraulic damping formula to process the base duty cycle, filtered slip ratio, filtered angular acceleration, displacement change, and the aforementioned adjustment gains to obtain the target duty cycle.

[0098] ;

[0099] In the formula: Target duty cycle; Basic duty cycle; Adjust the gain for slip ratio; The filtered slip ratio; Adjust the gain for angular acceleration; This is the angular acceleration after filtering; Adjust the gain for displacement; This represents the change in displacement.

[0100] The proportional hydraulic valve obtains the target duty cycle and adjusts the opening of the hydraulic valve. The hydraulic folding device adjusts the position and posture of the auxiliary track hydraulic cylinder according to the opening of the hydraulic valve, generating a telescopic state and forming a compliant control state. Thus, the controlled hydraulic stiffness is used to adaptively reduce drag and damp the impact of the external step.

[0101] S203, the traction control algorithm reads the transient slip ratio, which represents the slip state of the main track, from the data bus, and reads the preset slip safety boundary from the storage unit. The preset slip safety boundary is a characteristic value determined based on the vehicle's adhesion limit, and its value ranges from 0.15 to 0.25. When the transient slip ratio corresponding to the main track is greater than the preset slip safety boundary, the traction control algorithm generates a limiting torque command and calculates a torque reduction command based on the limiting torque command, which is then written into the data bus.

[0102] The vehicle controller acquires the torque reduction command and the filtered torque reduction amount, and reads the preset steady-state cavity pressure, preset drive wheel radius, and preset cross-sectional area from the storage unit. The preset steady-state cavity pressure is a balanced pressure determined based on the pre-charge pressure of the fluid accumulator. The preset drive wheel radius and preset cross-sectional area are determined by the physical geometric dimensions of the drive shaft and hydraulic cylinder, respectively. At the same time, the vehicle controller acquires the track deployment angle converted from the hydraulic cylinder displacement signal and acquires the vehicle pitch angle from the inertial measurement unit.

[0103] The vehicle controller calls the Jacobian function to process the track deployment angle and vehicle pitch angle, calculating the Jacobian mapping relationship between the auxiliary track hydraulic cylinder and the chassis components. The specific Jacobian calculation process combines the spatial coordinates of the hinge points at both ends of the auxiliary track hydraulic cylinder, the coordinates of the mechanical axis center of the auxiliary track, the actual physical length of the connecting rod, and the theoretical contact position between the auxiliary track and the ground, obtaining the result by cascading the geometric lever arm transformation matrix and the structural stiffness matrix. Subsequently, the vehicle controller calls the hydraulic compensation formula to calculate the target cavity pressure based on the steady-state cavity pressure, the filtered torque reduction, the drive wheel radius, the cross-sectional area, and the Jacobian mapping relationship.

[0104] To avoid the abnormal division-to-zero value caused by the Jacobian mapping component approaching zero when the linkage mechanism reaches its geometric dead point in the digital control system, the vehicle controller performs a boundary safety judgment on the denominator before performing the division operation. A boundary reference amplitude is preset to prevent division to zero. When the absolute value of the product of the drive wheel radius, cross-sectional area, and Jacobian mapping is greater than this boundary reference amplitude, the vehicle controller directly calculates the target cavity pressure using the following hydraulic compensation formula:

[0105] ;

[0106] In the formula: The target cavity pressure; This is the steady-state cavity pressure; This represents the torque reduction amount after filtering. The radius of the drive wheel; It is the cross-sectional area; This is a Jacobian mapping relation; The track deployment angle; The vehicle body pitch angle.

[0107] When the absolute value of the product of the drive wheel radius, cross-sectional area and Jacobian mapping relationship is less than or equal to the boundary reference amplitude, the system directly blocks the pressure compensation term and outputs the steady-state cavity pressure directly as the target cavity pressure.

[0108] The hydraulic chamber pressure sensor collects the chamber pressure of the auxiliary track hydraulic cylinder and outputs the actual chamber pressure. The on-board controller calculates the difference between the target chamber pressure and the actual chamber pressure to obtain the chamber pressure error, and inputs the chamber pressure error into the chamber pressure closed-loop control algorithm.

[0109] The cavity pressure closed-loop control algorithm utilizes a conventional proportional-integral-derivative (PID) control strategy. It multiplies the current cavity pressure error by a preset proportional feedback coefficient to establish the proportional control component. Simultaneously, it accumulates the cavity pressure errors within historical sampling periods along the discrete time axis and multiplies them by a preset integral feedback coefficient to establish the integral control component. It then calculates the difference between the cavity pressure error at the current sampling moment and the cavity pressure error at the previous adjacent sampling moment to obtain the error rate of change. This rate of change is then multiplied by a preset derivative feedback coefficient to establish the derivative control component. Finally, the proportional control component, integral control component, and derivative control component are algebraically superimposed to generate a pressure boosting command. The proportional hydraulic valve adjusts the hydraulic flow path according to the pressure boosting command, controlling the hydraulic electric pump assembly to boost the fluid accumulator and release oil, driving the actual cavity pressure to converge towards the target cavity pressure to form the regulated cavity pressure.

[0110] The onboard controller generates a normal support force compensation amount based on the torque reduction command. Under the hydraulic thrust of the pressure-adjusted chamber, the auxiliary track generates a normal support force that balances the normal support force compensation amount. This effectively converts the electric drive energy lost by the left and right main drive motors in suppressing slippage when driving the main track into the normal bearing force of the auxiliary track on the ground. This also effectively converts the electric drive energy lost by the left and right main drive motors in suppressing slippage into the normal bearing force of the chassis on the ground, ultimately completing the cascaded weight distribution of the entire vehicle across multiple domains.

[0111] See appendix Figure 5 In step S3 of this embodiment, the transition and smoothing module is responsible for the specific execution of the technical actions of the smooth transition at the top of the slope and the combined smoothing control of the downhill slope.

[0112] As an optional embodiment of the present invention, in the control link of the electric wheeled mountain vehicle traveling to the peak of the slope and transitioning to the slope working condition, the chassis is prone to nonlinear impact or mechanical interference bottoming out due to the instantaneous unloading of the physical support track; the present invention establishes a dual state machine handshake mechanism of non-contact distance estimation and structural stroke calibration at the execution end, and performs a smooth switch of slope unloading on the track side traction force after confirming that each mechanism is in physical position, so as to eliminate the sudden change of mechanical stress and smoothly transition the working condition.

[0113] S301, the rear distance sensor collects and outputs the rear distance signal during the uphill movement of the electric wheeled mountain vehicle. At the same time, the inertial measurement unit collects and outputs the vehicle pitch angle. The on-board controller obtains the rear distance signal and the vehicle pitch angle, and determines the pitch angle evaluation value at the top of the slope by combining the projection space coordinate transformation from the geometric center of the vehicle to the ground. The on-board controller reads the preset safety setting value from the storage unit. The preset safety setting value is a critical characteristic angle determined in advance based on the safety turning pitch angle to avoid bottoming out interference of the rear chassis when the whole vehicle passes through the peak. Its value range is between 2° and 6°.

[0114] When the pitch angle assessment value at the top of the slope is less than or equal to the preset safety setting value, the transition traverse module confirms that the electric wheeled mountain car has the crossing conditions and generates a transition request. Then, based on the transition request and combined with the rear distance signal, it determines that the walking rear wheel has reached the top of the slope and prioritizes outputting a support extension command to the wheel system support mechanism, driving the shock-absorbing wheel system support of the corresponding walking rear wheel to extend downward to support the ground. During this period, the main drive motor continues to drive the walking main track and auxiliary track to continue traveling until it determines that the walking front wheel has reached the top of the slope based on the forward distance signal collected by the front ranging sensor. At this time, it outputs a support extension command to the wheel system support mechanism, driving the shock-absorbing wheel system support of the corresponding walking front wheel to extend downward to support the ground, and outputs the support extension status.

[0115] After confirming full wheel load-bearing capacity, the transition smoothing module outputs an action command to the hydraulic folding device. The hydraulic folding device controls the auxiliary track hydraulic cylinder to retract according to the action command, so that the auxiliary track folds towards the center line of the vehicle body. The output hydraulic cylinder retraction state relies on the wheel structure as the gravity load-bearing entity for the whole vehicle to cross the top of the slope.

[0116] In the retracted state of the hydraulic cylinder and the extended state of the support, the limit sensor outputs a closing signal when the contact is closed, the hydraulic cylinder displacement sensor collects and outputs the hydraulic cylinder displacement signal, the vehicle controller obtains the closing signal and the hydraulic cylinder displacement signal and combines them to generate a real-time status; the vehicle controller reads the preset stroke threshold from the storage unit. The preset stroke threshold is set based on the mechanical residual displacement of the hydraulic rod when the auxiliary track hydraulic cylinder retracts and locks in the absolute limit position, and its value ranges from 0mm to 5mm.

[0117] The vehicle controller compares the real-time status with the preset travel threshold. When the real-time status is equal to the preset travel threshold and the closed signal is valid, it outputs a position confirmation command and establishes physical position confirmation.

[0118] S302, the transition module reads the limiting torque command output by the traction control algorithm from the data bus in the previous control cycle. This limiting torque command is preset to zero in the initial control cycle of the system. The vehicle controller subtracts the limiting torque command from the reference torque of the main drive motor to correct the current drive output and obtain the track traction command. The vehicle controller obtains the positioning confirmation command. When the positioning confirmation command is received, in order to eliminate the sudden change in mechanical stress caused by the main drive components being forcibly disconnected under load, the vehicle controller smoothly returns the track traction command to zero and outputs the power disconnection status to the data bus.

[0119] For the constraint process of the change rate of control command torque during the switching of working conditions, those skilled in the art can use a conventional slope limiter to implement it. The specific construction of the control unit is a well-known technology in the field and will not be described in detail here. The vehicle controller activates the wheel drive control logic according to the power disconnection state and controls the whole vehicle to enter the wheel drive state.

[0120] In wheel drive mode, in order to enable the system to accurately detect sudden changes in slope before entering a downhill section without relying on physical switches, the vehicle controller introduces a multi-source parallel feedforward discrimination matrix. When the vehicle pitch angle is less than zero degrees, which is manifested as the front of the vehicle tilting forward, the forward distance signal collected by the front ranging sensor is less than the preset variable amplitude safety distance, and the auxiliary track retracts due to the aforementioned auxiliary track retraction, causing the auxiliary track to leave the original slope surface, thereby causing the mechanical contact rod to disengage from physical contact and the mechanical contact rod stroke signal to leave the trigger state, the vehicle controller jointly judges from multiple sources that the downhill trigger condition is met and generates a downhill trigger command.

[0121] The vehicle controller outputs an unfolding command to the hydraulic folding device according to the downhill trigger command, and at the same time outputs a regenerative braking command to the main drive motor. The hydraulic folding device unfolds the auxiliary track according to the unfolding command and keeps it in the uphill pre-unfolded state. The main drive motor sets its internal generator mode according to the regenerative braking command to output reverse electromagnetic torque, generating and outputting regenerative braking state.

[0122] During regenerative braking, the on-board controller obtains the encoder linear velocity from the wheel encoder and uses it as the downhill velocity. Simultaneously, it performs a differential operation between the downhill velocity at the current sampling moment and the downhill velocity at the previous adjacent sampling moment to calculate the velocity change. The specific calculation process is as follows:

[0123] The vehicle controller obtains the downhill speed at the current sampling moment and retrieves the downhill speed at the previous adjacent sampling moment from the storage unit. It subtracts the downhill speed at the previous adjacent sampling moment from the downhill speed at the current sampling moment to calculate the vehicle speed change increment. Then, it divides the vehicle speed change increment by the system's fixed control sampling period time to calculate the real-time acceleration amplitude as the speed change.

[0124] The vehicle controller reads the preset speed safety boundary and preset step threshold from the storage unit. The preset speed safety boundary is set based on the safe linear velocity characteristic value corresponding to the maximum adhesion limit of the steering wheels when the vehicle is coasting on a steep slope, and its value ranges from 1.0 m / s to 2.5 m / s. The preset step threshold is set based on the upper limit of dynamic acceleration that the vehicle can tolerate when encountering a sudden drop in terrain or inertial dive, and its value ranges from 0.5 m / s. 2 Up to 1.2 m / s 2 Between, for example, 0.8 m / s 2 .

[0125] To ensure that the digital control system does not have a control blind spot under both constant speed descent and sudden descent conditions on long slopes, the transitional driving module performs step-by-step safety defense actions. When the downhill speed is greater than the speed safety boundary and the speed change is less than or equal to the step threshold, the on-board controller determines that a long-distance coasting has occurred on a gentle slope. At this time, the regenerative braking state of the main drive motor is maintained to perform electromagnetic energy absorption and speed limiting.

[0126] When the current downhill speed exceeds the preset speed safety boundary and the speed change exceeds the preset step threshold, the vehicle controller determines that the vehicle has deviated from the expected damping and is experiencing inertial acceleration and falling. It then outputs a braking command to the mechanical disc brake. The mechanical disc brake performs a clamping action according to the braking command and outputs physical friction torque. The high braking deceleration redundancy of mechanical friction and the electromagnetic braking reverse torque of the left and right main drive motors are algebraically superimposed on the shaft system to form a composite braking state and finally complete the downhill smooth control.

[0127] Upon completing downhill traverse control and reaching the bottom of the slope, the onboard controller, combining the forward distance signal collected by the front ranging sensor with the vehicle's pitch angle, determines that the front traveling wheels have reached the flat ground at the bottom of the slope. It then prioritizes sending a command to the wheel system support mechanism, driving the corresponding front traveling wheel's shock-absorbing wheel system support to extend downwards to support the ground. Subsequently, the onboard controller controls the main drive motor to release the compound braking or regenerative braking state, driving the main traveling track to continue traveling until, based on the rear distance signal collected by the rear ranging sensor, it determines that the rear traveling wheels have reached the flat ground at the bottom of the slope. At this point, it sends a command to the wheel system support mechanism, driving the corresponding rear traveling wheel's shock-absorbing wheel system support to extend downwards to support the ground. After confirming full wheel load, the onboard controller sends an action command to the hydraulic folding device, controlling the auxiliary track hydraulic cylinder to retract and fold up the auxiliary track, fully restoring the vehicle to a pure wheeled state.

[0128] See appendix Figure 6 In step S4 of this embodiment, the anti-rollover steering module is responsible for specifically executing the technical actions of the three-dimensional anti-rollover safety intervention and dynamic folding steering stage.

[0129] When an electric wheeled mountain vehicle travels on unstructured mountain terrain such as slopes and side slopes or performs large-angle obstacle crossing turns, its center of gravity will dynamically shift in multiple axes in space as the terrain slope changes. If the auxiliary tracks on both sides of the chassis are blindly grounded or lack asymmetric torque intervention, the vehicle is prone to rollover due to outward tilting caused by gravity. This invention dynamically calculates the Euclidean distance of the spatial center of gravity of the chassis assembly within the ground support polygon, and implements hydraulic hard locking and power-side differential correction cascade intervention at the instability critical point, which can improve the anti-rollover safety performance of the vehicle without affecting the normal steering of the vehicle.

[0130] S401, the anti-rollover module controls the vehicle controller to collect and output the vehicle pitch angle, roll angle and roll rate in real time from the inertial measurement unit. At the same time, it controls the vehicle controller to read the pre-stored track center distance, front and rear track wheel center distance and initial center of gravity height from the storage unit. The vehicle controller obtains the above dynamic attitude data and fixed geometric dimensions and combines them into attitude and structural parameters.

[0131] To fully map the anomalies in the vehicle's center of mass projection point caused by dynamic swaying or sloping terrain, the onboard controller invokes homogeneous coordinate projection transformation to perform spatial coordinate mapping of attitude and structural parameters; its clearly defined homogeneous solution process is as follows:

[0132] First, a three-dimensional spatial vector of the vehicle's center of gravity in the following local coordinate system is established. Then, a spatial homogeneous rotation matrix around the vehicle's longitudinal and transverse axes is constructed based on the real-time vehicle pitch and roll angles. At the same time, a three-dimensional translation matrix is ​​constructed in conjunction with the initial center of gravity height. The spatial three-dimensional vector is then concatenated and multiplied by the homogeneous rotation matrix and the three-dimensional translation matrix to complete the spatial homogeneous coordinate transformation. The resulting coordinates of the center of gravity projection in the absolute ground two-dimensional coordinate system are then calculated and output.

[0133] Furthermore, based on the physical contour extreme values ​​of the track center distance and the front and rear track wheel center distances, the vehicle controller calculates a closed convex polygon formed by the topological topology of the four extreme vertices of the actual ground contact area corresponding to the current deployment positions of the front and rear tracks, the main track, and the auxiliary track, and establishes this as the boundary of the supporting polygon. When calculating the center of gravity projection coordinates, the initial center of gravity height is determined in advance through a static weighing load calibration test, and the rated personnel weight and the frame load variation coefficient are included. If the center of gravity projection point is located inside the supporting polygon, the output stability margin distance is positive; if it falls outside, it is negative. The vehicle controller calls the geometric distance calculation to process the center of gravity projection coordinates and the supporting polygon boundary, and calculates and outputs the current stability margin by solving the shortest Euclidean distance from the center of gravity projection point to each side segment of the supporting polygon boundary.

[0134] S402, the anti-rollover module controls the vehicle controller to read preset safety settings from the storage unit. The preset safety settings are a set of boundary characteristic values ​​that are predetermined based on the critical geometric overturning boundary of the vehicle's roll instability and the upper limit of the pitch angle that allows dynamic steering. The value range includes a lower limit of distance from 50mm to 150mm and an upper limit of pitch angle from 10° to 20°. For example, a lower limit of geometric distance of 100mm and an upper limit of pitch angle of 15° can be selected.

[0135] The on-board controller compares the calculated stability margin with the lower limit of the preset safety setting. To prevent the control signal from experiencing high-frequency sudden oscillations at the geometric critical boundary, which could lead to a control dead zone caused by frequent pressure adjustments of the proportional hydraulic valve, the on-board controller introduces a preset hysteresis filter interval during the comparison process. The preset hysteresis filter interval has a hysteresis width of 20mm. That is, when the stability margin falls below 100mm, an anti-rollover interruption command is triggered, and the interruption is only lifted when the stability margin rises back to above 120mm. When the stability margin is less than the lower limit of the preset safety setting, the on-board controller determines that the electric wheeled mountain vehicle is in an unstable and over-limit state, immediately triggers the anti-rollover interruption, and outputs an anti-rollover interruption command.

[0136] The vehicle controller outputs pressure holding and limiting commands to the proportional hydraulic valve according to the anti-rollover interruption command, controls the two-way hydraulic lock and the two-way balance valve to forcibly lock the hydraulic oil circuit, and at the same time closes the oil supply and return channels inside the proportional hydraulic valve to lock the hydraulic oil circuit, so that the auxiliary track hydraulic cylinder maintains a safe support state, thereby relying on the rigid hydraulic strut to bear the lateral rollover moment.

[0137] Simultaneously, the vehicle controller outputs roll suppression differential commands to the left and right main drive motors respectively according to the roll suppression differential command. The left and right main drive motors execute asymmetrical torque output on both sides according to the roll suppression differential command, so that the camber motor increases torque and the camber motor decreases torque, forming a roll suppression torque on the vehicle axle system. The dynamic shear torque of the main drive wheels on the ground is used to actively correct the vehicle's roll posture.

[0138] In addition, when the electric wheeled mountain vehicle is in a safe and stable range, that is, when the current stability margin is detected to be within the preset safety setting value range (in this embodiment, the stability margin is greater than or equal to 100mm), and the vehicle controller detects the steering signal output by the steering input device, the system automatically switches to the dynamic folding steering control chain.

[0139] In the dynamic folding steering control chain, the on-board controller obtains the real-time vehicle pitch angle and compares it with the preset severe slope angle threshold, which is preset to 30°.

[0140] When the vehicle pitch angle is less than the severe slope angle threshold (less than 30°), the on-board controller outputs a folding intervention command to the hydraulic folding device. The hydraulic folding device controls the auxiliary track hydraulic cylinder to retract according to the folding intervention command to fold the auxiliary track and lift it completely off the ground, thereby eliminating the mechanical interference of the steering friction resistance torque generated by the auxiliary track grounding on the steering action.

[0141] While the auxiliary tracks retract, the differential control algorithm generates a steering differential command based on the steering signal through a two-wheel differential kinematic transformation model. The left and right main drive motors execute differential drive actions on the dual axle systems according to the steering differential command. By controlling the speed difference between the two walking wheels to generate a preset offset ratio, the lateral yaw resistance is overcome, and the electric wheeled mountaineering vehicle is safely controlled to enter the steering control state.

[0142] When the vehicle's pitch angle is greater than or equal to the severe slope angle threshold (greater than or equal to 30°), the onboard controller directly blocks the folding intervention command in the underlying logic, forcing the auxiliary track to remain in an unfolded, grounded, unfolded state to maintain the maximum area supporting the polygon boundary. At the same time, the differential control algorithm directly generates a steering differential command based on the steering signal, controlling the left and right main drive motors to drive the main track, in order to overcome the additional steering friction resistance generated by the auxiliary track grounding and obtain a rollover safety margin at the cost of the additional steering friction resistance.

[0143] To further aid in understanding the technical solution of this invention, a specific application embodiment is given below, taking into account the actual operating conditions of a heavy-duty electric wheeled mountaineering vehicle.

[0144] An electric tracked mountain vehicle is set to perform an uphill task on an unstructured mountain terrain with a slope of 15°. The initial fusion reference speed is set to 1.2 m / s. A 100 mm high rock step obstacle is present ahead. When the wheels initially touch the leading edge of the rock step, the onboard controller acquires the operating data of the left and right main drive motors. The torque change rate of the main motors is set to 45.0 N·m / s, and the real-time pitch velocity of the vehicle body output by the inertial measurement unit is 1.8 rad / s. The onboard controller reads the preset first phase plane normalization coefficient (0.04) and the preset second phase plane normalization coefficient (1.2) from the storage unit, substitutes them into the step recognition formula, and calculates the phase plane characteristic values:

[0145] ;

[0146] Since the calculated phase plane eigenvalue of 2.81 is greater than the preset trigger threshold of 2.0, the terrain pre-control module determines that a high-intensity sudden step impact has occurred ahead. It immediately generates a step identification result and issues an advance trigger command. Based on the advance trigger command, it controls the auxiliary track to deploy to output the auxiliary track deployment state, and causes the left main drive motor and the right main drive motor to enter the low-speed, high-torque state in advance to switch to track working condition.

[0147] With the auxiliary tracks deployed and in low-speed, high-torque mode, the filtered slip ratio of the adaptive filter is 0.25, and the filtered vehicle pitch acceleration is 1.2 rad / s². 2 By differentially calculating the sensor signals within the reference coordinate system, the displacement change was determined to be 0.02m. Simultaneously, the vehicle controller, through an algebraic mapping function, calculated a base duty cycle of 60%. The system further reads preset gain parameters from the storage unit, including a slip ratio adjustment gain of 15, an angular acceleration adjustment gain of 8, and a displacement adjustment gain of 50. The system then uses the hydraulic damping formula to process the base duty cycle, filtered slip ratio, filtered angular acceleration, displacement change, and the aforementioned adjustment gains to calculate the target duty cycle.

[0148] ;

[0149] The proportional hydraulic valve obtains the target duty cycle of 45.65% and adjusts the opening of the hydraulic valve. The hydraulic folding device adjusts the position of the auxiliary track hydraulic cylinder according to the opening of the hydraulic valve, generating a telescopic state and forming a compliant control state, thus completing the adaptive drag reduction and damping adjustment.

[0150] As the obstacle-crossing process progresses, the traction control algorithm reads the transient slip rate from the data bus and detects that it exceeds the set slip safety boundary of 0.20. It then issues a torque limiting command and calculates a torque reduction command, writing it into the data bus, resulting in a filtered torque reduction of 120 N·m. To compensate for the electric drive energy lost due to slip suppression, the system reads the steady-state chamber pressure of the fluid accumulator as 8.0 MPa (i.e., 8.0 × 10⁻⁶). 6 (Pa), the current chassis structure has a drive wheel radius of 0.3m and a hydraulic cylinder cross-sectional area of ​​0.005m³. 2 Meanwhile, the system obtains the Jacobian mapping relationship through real-time kinematics calculation. The value is 0.8. After confirming that the absolute value of the product of all parameters is much greater than the boundary reference amplitude, the target cavity pressure is calculated using the hydraulic compensation formula:

[0151] ;

[0152] The calculated target chamber pressure is 8.1 MPa. The hydraulic chamber pressure sensor collects the chamber pressure of the auxiliary track hydraulic cylinder and outputs the actual chamber pressure. The on-board controller calculates the difference between the target chamber pressure and the actual chamber pressure to obtain the chamber pressure error, and inputs it into the chamber pressure closed-loop control algorithm to generate a boost command. The proportional hydraulic valve adjusts the hydraulic flow channel according to the boost command and controls the hydraulic electric pump assembly to boost the fluid accumulator, driving the actual chamber pressure to converge towards the target chamber pressure to form the adjusted chamber pressure. Under the hydraulic thrust of the adjusted chamber pressure, the auxiliary track generates a normal support force that balances the normal support force compensation amount, ultimately completing the cascaded weight distribution of the entire vehicle across multiple domains.

[0153] To verify the effectiveness of the above technical solution, experiments and effect comparisons were conducted at a standard off-road test track.

[0154] The experiment selected a rough rocky road section with an average slope of 20° and multiple discrete protruding steps evenly distributed on the surface. Multiple benchmark tests were conducted using both the traditional control strategy without activating the present invention and the vehicle with the full-condition automatic control system of the present invention activated. During the experiment, the on-board sensor array synchronously recorded various dynamic physical quantities at a fixed sampling frequency.

[0155] Experimental results show that when faced with continuous steps of the same height, vehicles using traditional control strategies cannot anticipate sudden terrain changes and can only passively adjust after the tracks experience a physical impact, resulting in severe rearward tilting and deteriorated vehicle attitude control performance. Furthermore, during the transient process of traversing the steps, the drive wheels experience freewheeling and slippage. In contrast, the control system equipped with this invention effectively identifies sudden impacts through a state phase plane feedforward algorithm and proactively adjusts the damping of the proportional hydraulic valve, substantially improving the vehicle's maneuverability and anti-roll safety in complex terrain.

[0156] See appendix Figure 7 , Figure 7 The evolution of vehicle attitude over the same obstacle-crossing timeline is shown. The vehicle pitch angle corresponding to the traditional control strategy is represented by a dashed line with a triangle mark. Due to the lag in the system's adjustment, it exhibits severe lag fluctuations with large-amplitude overshoot after touching the step obstacle, with the peak value of the vehicle pitch angle reaching 21.8°.

[0157] The vehicle pitch angle corresponding to the control strategy of this invention is represented by a solid line with a circular mark. Due to the introduction of the feedforward active recognition mechanism, its peak exhibits obvious advance suppression characteristics. The maximum value of the vehicle pitch angle is stably controlled at around 16.0°, and the fluctuation slope is more gentle, reflecting the safety gain effect of low amplitude and smooth transition.

[0158] See appendix Figure 8 , Figure 8The transient slip ratio control curve is depicted using a dashed line, recording the upward surge of the transient slip ratio when it abruptly slips upon touching the step, followed by a rapid reduction of the peak under active control intervention, with the highest value only rising to 0.125 before quickly converging to the baseline of 0.05.

[0159] Meanwhile, the dynamic response curve of the normal support force is depicted with a wide solid line, showing that while the driving torque on the motor side is reduced, the normal support force is raised in reverse synchronous compensation from the default base value of 3.0kN due to the active drive of the hydraulic compensation formula, and finally stabilizes at around 5.8kN. This demonstrates the effect of the energy cascading redistribution technology that converts the electric drive energy lost on the drive side due to the suppression of slippage into the energy cascading redistribution of the chassis's normal bearing capacity on the ground.

[0160] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for automatic control of an electric wheeled mountain vehicle under all working conditions, characterized in that, Includes the following steps: In pure wheel mode, the reference vehicle speed is calculated by combining the longitudinal acceleration and the encoder linear velocity with the reference vehicle speed formula, and the transient slip ratio is calculated based on the fused reference vehicle speed. When receiving a reversing or uphill command, the system acquires the torque change rate and pitch angular velocity to construct a state phase plane and calculates the phase plane characteristic value. Based on the phase plane characteristic value, it controls the auxiliary track to deploy and switch to track working condition. Based on the transient slip rate and hydraulic damping formula, it obtains the target duty cycle adjustment proportional hydraulic valve. When the transient slip rate is greater than the slip safety boundary, it generates a torque reduction command. It calculates the target cavity pressure by combining the Jacobian mapping relationship, so as to drive the actual cavity pressure to converge to the target cavity pressure to generate a normal support force. Collect distance signals and vehicle pitch angle to determine the pitch angle evaluation value at the top of the slope, generate a transition request to retract the auxiliary track and restore wheel drive, deploy the auxiliary track and output regenerative braking state when the downhill trigger condition is met, combine downhill speed and speed change to output braking command to enter downhill working condition, and restore the pure wheel state when reaching the flat ground at the bottom of the slope. The vehicle body attitude parameters are collected to calculate the center of gravity projection coordinates and stability margin. Based on the stability margin, an anti-rollover interruption command is output to maintain a safe support state. The main drive motor is controlled to generate roll suppression torque. When a steering signal is obtained, the folding state of the auxiliary track is controlled based on the vehicle body pitch angle. Differential drive action is executed to enter the steering control state.

2. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 1, characterized in that, Before the step of combining longitudinal acceleration and encoder linear velocity to call the reference vehicle speed formula to calculate the fused reference vehicle speed, an initialization step is also included: After the vehicle controller performs power-on initialization, it reads the calibration parameters in the storage unit to establish the reference coordinates, and combines the distance signals collected by the front and rear distance sensors, as well as the mechanical contact rod travel signal collected by the mechanical contact rod of the limit switch, into a trigger matrix through logical OR operation. The hydraulic cylinder displacement signal collected by the hydraulic cylinder displacement sensor is obtained, and the auxiliary track reference angle is calculated by combining the geometric dimensions of the chassis mechanical linkage and written into the reference coordinates. A status polling request is sent to the motor driver and hydraulic valve. When the trigger matrix and the reference coordinates are successfully established, and the status of the motor driver and the hydraulic valve meet the preset self-test reference status, a parking release command is output to control the auxiliary track hydraulic cylinder to retract the auxiliary track, and simultaneously extend the shock-absorbing wheel system brackets of the front wheel and the rear wheel downwards, so that the electric wheel-tracked mountain vehicle enters the pure wheel state. The calibration parameters include the self-test reference state, the initial preset fusion weight coefficient, the preset first phase plane normalization coefficient, the preset second phase plane normalization coefficient, and the preset trigger threshold. The self-test reference state is preset based on the communication level characteristics between the motor driver and the hydraulic valve in a fault-code-free state.

3. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 2, characterized in that, In pure wheel mode, the steps of calculating the fused reference vehicle speed by combining longitudinal acceleration and encoder linear velocity using the reference vehicle speed formula, and calculating the transient slip ratio based on the fused reference vehicle speed, include: The initial velocity is established by acquiring the longitudinal acceleration collected by the inertial measurement unit and the encoder linear velocity collected by the wheel encoder. Based on the suspension pressure output by the pressure sensor and the preset suspension threshold, the fusion weighting coefficient is derived and smoothed by a low-pass filter. The reference vehicle speed formula is called to calculate the product of the fusion weight coefficient and the sum of the time integrals of the initial speed and the longitudinal acceleration. The product of the difference between the fusion weight coefficient and the encoder linear speed is added to obtain the fusion reference vehicle speed. The reference speed is compared with the fused reference speed and the drive-side calculated linear speed fed back by the main drive motor. The larger value is selected to determine the reference speed. When the reference speed is greater than zero, the difference between the drive-side calculated linear speed and the fused reference speed is divided by the reference speed to calculate the transient slip ratio. The transient slip ratio is then written into the data bus. The transient slip ratio characterizes the slipping state of the main track, and the suspension threshold is preset based on the reference pressure caused by the inherent weight of the shock-absorbing wheel system bracket and the spring preload when the vehicle is unloaded.

4. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 1, characterized in that, When receiving a reversing or uphill command, the steps of acquiring the torque change rate and pitch angular velocity to construct a state phase plane and calculating phase plane characteristic values, and controlling the auxiliary track deployment to switch to track working mode based on the phase plane characteristic values ​​include: When the reversing command or the uphill command is received, the torque change rate corresponding to the torque of the left main drive motor and the right main drive motor, and the pitch angular velocity output by the inertial measurement unit are obtained, and used as the horizontal axis and the vertical axis to construct the state phase plane respectively. The step recognition formula is called to calculate the square of the product of the preset first phase plane normalization coefficient and the torque change rate, and then the square of the product of the preset second phase plane normalization coefficient and the pitch angular velocity is added. The square root operation is performed on the sum to calculate the phase plane characteristic value. When the phase plane feature value is greater than the preset trigger threshold, a step recognition result is generated, an advance trigger command is issued, and an unfolding command is output to the hydraulic folding device according to the advance trigger command, so that the auxiliary track unfolds and outputs the auxiliary track unfolding state. At the same time, a switching command is output to the motor driver to control the left main drive motor and the right main drive motor to enter the low speed torque state, drive the main track to provide basic traction force, so as to switch to the track working condition. The first phase plane normalization coefficient and the second phase plane normalization coefficient are preset based on the ratio between the rated torque change rate range of the left main drive motor and the right main drive motor and the maximum dynamic range of the pitch angular velocity. The trigger threshold is preset based on the critical impact energy generated when the electric wheeled mountain vehicle hits the step.

5. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 4, characterized in that, The steps for obtaining the target duty cycle adjusting proportional hydraulic valve based on the transient slip ratio and hydraulic damping formula include: The transient slip ratio, vehicle pitch angle acceleration, and torque reduction command generated in the previous control cycle are input into the adaptive filter. Frequency domain matching processing is performed based on the valve body response time constant, and the filtered slip ratio, filtered torque reduction, and filtered angular acceleration are output. Extract the hydraulic cylinder displacement signal at the current sampling time and the hydraulic cylinder displacement signal at the previous adjacent sampling time, and perform differential calculation based on the time axis to obtain the displacement change. The trajectory vector in the state phase plane is extracted, and its geometric phase angle and magnitude are transformed by piecewise linear interpolation using an algebraic mapping function to calculate the basic duty cycle. The target duty cycle is calculated by successively subtracting the product of the preset slip ratio adjustment gain and the filtered slip ratio, the product of the preset angular acceleration adjustment gain and the filtered angular acceleration, and the product of the preset displacement adjustment gain and the displacement change from the base duty cycle using the hydraulic damping formula. The proportional hydraulic valve obtains the opening of the target duty cycle regulating hydraulic valve, adjusts the position of the auxiliary track hydraulic cylinder to generate a telescopic state and outputs a compliant control state. The preset slip ratio adjustment gain, the preset angular acceleration adjustment gain, and the preset displacement adjustment gain are preset based on the inherent stiffness of the hydraulic flow channel and the desired fluid damping coefficient set in the frame assembly.

6. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 5, characterized in that, The steps of generating a torque reduction command when the transient slip ratio is greater than the slip safety boundary, calculating the target cavity pressure in conjunction with the Jacobian mapping relationship, and driving the actual cavity pressure to converge towards the target cavity pressure to generate a normal support force include: When the transient slip ratio exceeds the preset slip safety boundary, the traction control algorithm generates a limiting torque command and calculates the corresponding torque reduction command. The track deployment angle and vehicle pitch angle, derived from the displacement signal of the hydraulic cylinder, are obtained, and the Jacobian function is called to calculate the Jacobian mapping relationship between the auxiliary track hydraulic cylinder and the chassis component. When the absolute value of the product of the drive wheel radius, cross-sectional area and the Jacobian mapping relationship is greater than the set boundary reference amplitude, the hydraulic compensation formula is invoked to divide the filtered torque reduction by the aforementioned absolute value of the product, and then add the steady-state cavity pressure to calculate the target cavity pressure. The actual cavity pressure collected by the hydraulic cavity pressure sensor is obtained, the cavity pressure error between the target cavity pressure and the actual cavity pressure is calculated and input into the cavity pressure closed-loop control algorithm, a pressure boosting command is generated, and the actual cavity pressure is driven to converge towards the target cavity pressure to form the adjusted cavity pressure; The auxiliary track, under the thrust of the pressure-adjusted cavity, generates a normal support force that balances the normal support force compensation amount, and performs cascaded weight distribution; The slip safety boundary is preset based on the vehicle adhesion limit, and the steady-state cavity pressure is preset based on the pre-charge pressure of the fluid accumulator.

7. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 1, characterized in that, The steps for acquiring distance signals and vehicle pitch angle to determine the hill crest pitch angle assessment value, generating a transition request to retract auxiliary tracks and restore wheel drive include: By combining the rear distance signal collected by the rear ranging sensor as the distance signal and the vehicle pitch angle collected by the inertial measurement unit, the evaluation value of the hill crest pitch angle is determined; When the slope crest pitch angle assessment value is less than or equal to the preset safety setting value, the transition request is generated. Based on the transition request and combined with the rear distance signal, when it is determined that the walking rear wheel has reached the top of the slope, the wheel system support mechanism is given priority to output a command to drive the shock-absorbing wheel system support of the corresponding walking rear wheel to extend downward to support the ground. The left main drive motor and the right main drive motor continue to drive the walking main track and auxiliary track to continue traveling until the forward distance signal collected by the front ranging sensor determines that the walking front wheel has reached the top of the slope. Then, the wheel system support mechanism is output to drive the shock-absorbing wheel system support of the corresponding walking front wheel to extend downward to support the ground to output the support extension state. After confirming the full wheel load, the output action command controls the auxiliary track hydraulic cylinder to retract and outputs the hydraulic cylinder to retract state; The combination of the closing signal output by the limit sensor and the displacement signal of the hydraulic cylinder generates a real-time status. When the real-time status is equal to the preset stroke threshold and the closing signal is valid, a position confirmation command is output and physical position confirmation is established. Upon receiving the positioning confirmation command, the current track traction command is smoothly reduced to zero and a power disconnection state is output to the data bus, and the wheel drive control logic is activated to restore the wheel drive. The safety setting value is preset based on the safety turning angle to avoid chassis bottoming interference, and the stroke threshold is preset based on the mechanical residual displacement of the auxiliary track hydraulic cylinder.

8. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 7, characterized in that, The steps of deploying auxiliary tracks and outputting regenerative braking when the downhill trigger condition is met, outputting braking commands based on downhill speed and speed change to enter downhill working condition, and restoring the pure wheeled state upon reaching the flat ground at the bottom of the slope include: When the vehicle pitch angle is less than zero degrees and the forward distance signal collected by the front ranging sensor as the distance signal is less than the preset variable amplitude safety distance, and the mechanical contact rod stroke signal in the trigger matrix is ​​out of the trigger state, it is determined that the downhill trigger condition is met and a downhill trigger command is generated to enter the downhill working condition. According to the downhill trigger command, the hydraulic folding device is output a unfolding command to unfold the auxiliary track, and the left main drive motor and the right main drive motor are instructed to output the regenerative braking state. The change in speed is calculated by differentiating the downhill speed at the current sampling time with the downhill speed at the previous adjacent sampling time. When the downhill speed is greater than the preset speed safety boundary and the speed change is greater than the preset step threshold, the braking command is output to the mechanical disc brake to perform a clamping action, which together with the regenerative braking state forms a compound braking state. When the downhill driving control is completed and the vehicle reaches the bottom of the slope, the front wheel is driven to extend downward to support the ground when the forward distance signal and the vehicle pitch angle are used to determine that the front wheel has reached the bottom of the slope. The left and right main drive motors are then controlled to release the compound braking state and drive the main track to continue driving until the rear wheel is driven to extend downward to support the ground when the rear distance signal is used to determine that the rear wheel has reached the bottom of the slope. The rear wheel shock absorber is then driven to extend downward to support the ground. After confirming that the entire wheel is under load, the hydraulic folding device is controlled to retract the auxiliary track and restore the vehicle to a pure wheel state. The speed safety boundary is preset based on the safety linear velocity characteristic value corresponding to the maximum adhesion limit, and the step threshold is preset based on the allowable upper limit of dynamic acceleration.

9. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 1, characterized in that, The steps for collecting vehicle attitude parameters and calculating the center of gravity projection coordinates and stability margin include: The vehicle pitch angle, roll angle and roll rate are collected and combined to form the vehicle attitude parameters. The track center distance, the front and rear track wheel center distance and the initial center of gravity height are combined as structural parameters to form attitude and structural parameters. Call the homogeneous coordinate projection transformation to construct a spatial homogeneous rotation matrix and combine it with the initial centroid height to construct a three-dimensional translation matrix for calculation, and output the centroid projection coordinates; Based on the topology of the extreme vertices of the actual grounding area of ​​the electric wheeled mountain vehicle, the polygon is calculated as the boundary of the supporting polygon; The geometric distance calculation is invoked to solve for the distance from the centroid projection coordinates to each side segment of the supporting polygon boundary, and the current stability margin is calculated and output.

10. The automatic control method for an electric wheeled mountain vehicle under all working conditions according to claim 9, characterized in that, The steps of maintaining a safe support state by outputting an anti-rollover interruption command based on the stability margin, controlling the main drive motor to generate roll suppression torque, controlling the folding state of the auxiliary tracks based on the vehicle pitch angle when a steering signal is obtained, and executing differential drive action to enter the steering control state include: Within a preset hysteresis filter range, the stability margin is compared with the distance lower limit in the preset safety setting. When the stability margin falls below the distance lower limit, the anti-rollover interruption command is output. According to the anti-rollover interruption command, a pressure holding and pressure limiting command is output to lock the hydraulic flow channel, so that the auxiliary track hydraulic cylinder maintains the safe support state; According to the anti-rollover interruption command, roll suppression differential command is output to the left main drive motor and the right main drive motor to execute asymmetrical torque output, forming the roll suppression torque; When the vehicle pitch angle and the stability margin are both within the preset safety setting range, and the steering signal output by the steering input device is obtained, the real-time vehicle pitch angle is compared with the preset severe slope angle threshold. When the vehicle pitch angle is less than the severe slope angle threshold, a folding intervention command is output to fold the auxiliary track, and the differential control algorithm generates a steering differential command based on the steering signal to execute the differential drive action, thus entering the steering control state; When the vehicle body pitch angle is greater than or equal to the severe slope angle threshold, the folding intervention command is blocked, so that the auxiliary track remains in an unfolded, grounded, unfolded state. The differential control algorithm generates a steering differential command based on the steering signal, and controls the left main drive motor and the right main drive motor to drive the main track to perform in-situ differential drive action.

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