Balance car control method

Abstract

The invention provides a balance car control method, and relates to the technical field of balance cars. Comprising the following steps of: acquiring a slope value of a road surface and judging a road surface type and a slope grade in a grading manner to apply basic compensation; monitoring a slope variation to apply additional compensation; acquiring pressure data in front, back, left and right directions and calculating a pressure difference to apply load torque compensation; adjusting the load torque compensation on the left and right sides in combination with a vehicle speed during turning; the rate of change of pressure data is monitored to adjust load torque compensation. Through the multi-dimensional cooperative control means of graded gradient compensation, gravity center shift accurate compensation and load sudden change emergency compensation, accurate control over the balance car under complex working conditions such as gradient change, gravity center shift, turning driving and load sudden change is achieved, and the driving stability and safety are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of balance car, in particular to a balance car control method. BACKGROUND

[0002] With the continuous growth of short-distance travel demand, balance car has become the mainstream of travel tools due to its flexibility, convenience, energy saving and environmental protection. Its use scenarios have extended from flat urban roads to community paths, suburban slopes and other diversified road conditions. During driving, complex situations such as changes in road slope, dynamic shifts in passenger's center of gravity, fluctuations in turning speed and sudden changes in load often occur, which puts higher requirements on the dynamic control accuracy, attitude stability and safety redundancy of balance car. The traditional control scheme gradually fails to adapt to the precise control requirements under multiple working conditions.

[0003] The traditional balance car control method mostly adopts a single slope compensation strategy, without grading determination of road types and slope levels, which leads to insufficient motor power output on uphill and unbalanced brake force regulation on downhill, easily causing speed out of control. The judgment of front-to-back and left-to-right shifts in center of gravity lacks precise pressure data support, the compensation amount does not match the shift degree, and it is difficult to effectively offset the attitude imbalance risk. When turning, the load torque compensation is not adjusted dynamically combined with vehicle speed, which cannot respond to the centrifugal force generated by high-speed turning. There is no effective monitoring mechanism for the change rate of pressure data, and the response is lagged in the face of sudden load mutation scenes such as rapid movement of passengers and sudden increase and decrease of load, which easily causes the car body to shake or even lose control, seriously affecting the driving safety and riding experience.

[0004] Therefore, it is necessary to design a balance car control method to solve the problems of non-graded slope compensation, low precision of center of gravity shift compensation, insufficient response to centrifugal force during turning, and lag response to load mutation in the prior art. SUMMARY

[0005] In view of this, the present application provides a balance car control method to solve the problems of non-graded slope compensation, low precision of center of gravity shift compensation, insufficient response to centrifugal force during turning, and lag response to load mutation in the prior art.

[0006] In one aspect, the present application provides a balance car control method, comprising: obtaining a slope value of a road surface, determining a road surface type and a slope level based on the slope value, and applying a basic compensation to electric power torque and brake force based on the road surface type and the slope level; monitoring a slope change amount when the slope changes, and applying an additional compensation to the electric power torque and the brake force based on the slope change amount; obtaining front-to-back direction pressure data and calculating a front-to-back pressure difference, determining a front-to-back shift direction based on the front-to-back pressure difference, and applying a load torque compensation to the opposite side of the front-to-back shift direction; Obtain left and right direction pressure data and calculate left and right pressure difference, determine the direction of the center of gravity left and right deviation based on the left and right pressure difference, and apply a heavy torque compensation to the inner side wheels during turning in combination with vehicle speed; Monitor the rate of change of pressure data, and adjust the heavy torque compensation based on the rate of change of pressure data.

[0007] Further, when determining the road surface type and the slope grade based on the slope value, it includes: When the slope value is greater than zero and the slope value is greater than the slope threshold, the road surface type is uphill; When the slope value is less than zero and the slope value is less than the inverse of the slope threshold, the road surface type is downhill; When the absolute value of the slope value is less than or equal to the slope threshold, the road surface type is flat; When the absolute value of the slope value is in the first slope interval, the slope grade is gentle; When the absolute value of the slope value is in the second slope interval, the slope grade is medium; When the absolute value of the slope value is in the third slope interval, the slope grade is steep.

[0008] Further, when applying basic compensation to electric torque and braking force based on the road surface type and the slope grade, it includes: When the road surface type is uphill, the corresponding basic torque compensation ratio in the pre-set slope-torque compensation relationship is extracted according to the slope grade, and compensation is applied to the electric torque according to the basic torque compensation ratio; When the road surface type is downhill, the corresponding basic brake compensation ratio in the pre-set slope-brake compensation relationship is extracted according to the slope grade, and compensation is applied to the braking force according to the basic brake compensation ratio; When the road surface type is flat, the current electric torque and braking force remain unchanged.

[0009] Further, when applying additional compensation to electric torque and braking force based on the slope change amount, it includes: When the road surface type changes before and after the slope value changes, basic compensation is applied to electric torque and braking force based on the current road surface type and the current slope grade.

[0010] Further, when applying additional compensation to electric torque and braking force based on the slope change amount, it further includes: When the slope change amount is greater than the slope mutation threshold and the road surface type is always uphill, the electric torque compensation is added according to the pre-set additional torque compensation ratio based on the basic torque compensation ratio; When the slope change amount is greater than the slope mutation threshold and the road surface type is always downhill, then on the basis of the basic brake compensation ratio, add brake force compensation by a preset additional brake compensation ratio; When the slope change amount is less than or equal to the slope mutation threshold, then keep the current electric power torque and brake force unchanged.

[0011] Further, when the front-rear pressure difference is used to determine the front-rear shift direction of the center of gravity, and a load torque compensation is applied to the opposite side of the front-rear shift direction, it includes: The front-rear pressure difference is equal to the difference between the front side pressure value and the rear side pressure value; When the front-rear pressure difference is greater than zero, it is determined that the center of gravity shifts to the front side, and a load torque compensation is applied to the rear side; When the front-rear pressure difference is less than zero, it is determined that the center of gravity shifts to the rear side, and a load torque compensation is applied to the front side; When the front-rear pressure difference is equal to zero, no load torque compensation is applied; The compensation amount of the load torque compensation is proportional to the absolute value of the front-rear pressure difference.

[0012] Further, when the left-right pressure difference is used to determine the left-right shift direction of the center of gravity, and a load torque compensation is applied to the inner side wheels during turning combined with vehicle speed, it includes: The left-right pressure difference is equal to the difference between the left side pressure value and the right side pressure value; When the left-right pressure difference is greater than zero, it is determined that the center of gravity shifts to the left side, and a load torque compensation is applied to the right side; When the left-right pressure difference is less than zero, it is determined that the center of gravity shifts to the right side, and a load torque compensation is applied to the left side; When the left-right pressure difference is equal to zero, no load torque compensation is applied; The compensation amount of the load torque compensation is proportional to the absolute value of the front-rear pressure difference.

[0013] Further, when the left-right pressure difference is used to determine the left-right shift direction of the center of gravity, and a load torque compensation is applied to the inner side wheels during turning combined with vehicle speed, it further includes: When the vehicle speed is greater than the vehicle speed threshold, the left-right load torque compensation is increased by a proportion of the vehicle speed divided by the vehicle speed threshold.

[0014] Further, when the pressure data change rate is used to adjust the load torque compensation, it includes: When the pressure data change rate is greater than the load mutation threshold, the front-rear and left-right load torque compensations are increased by using an emergency compensation ratio.

[0015] Further, when the pressure data change rate is used to adjust the load torque compensation, it further includes: When the pressure data change rate is less than or equal to the load mutation threshold, the current load torque compensation is kept unchanged.

[0016] Compared with the prior art, the balance car control method has the beneficial effects that the balance car control method acquires a road slope value and judges a road type and a slope grade in stages, applies a basic torque or brake force compensation in a targeted manner, monitors a slope change amount, and applies an additional compensation when the road type or the slope changes suddenly, effectively solving the problems of insufficient power of the balance car on an uphill and out-of-control speed of the balance car on a downhill in different slope road conditions; the balance car control method collects front, rear, left and right pressure data, accurately judges a gravity center deviation direction, and applies a load torque compensation to an opposite side, and increases the load torque compensation of the left and right sides in proportion in combination with a vehicle speed threshold when turning, which can offset the attitude imbalance risk caused by the gravity center deviation and centrifugal force in high-speed turning; the balance car control method monitors a pressure data change rate, and when the pressure data change rate exceeds a load mutation threshold, the balance car control method increases the load torque compensation of the front and rear sides and the left and right sides in proportion by using an emergency compensation, which can quickly respond to a load mutation scene, avoid body shaking or out-of-control caused by sudden load change, and overall realize accurate control of the balance car in complex working conditions such as slope change, gravity center deviation, turning and load mutation, and significantly improve the driving stability and safety. BRIEF DESCRIPTION OF DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to limit the present application thereto. Moreover, the use of the same reference symbols in different drawings indicates similar or identical items. Figure 1 A balance car control method flow chart is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood and so that the scope of the present application can be conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0019] Referring to Figure 1 As shown in the drawings, in some embodiments of the present application, a balance car control method comprises: Obtaining a slope value of the road surface, determining a road surface type and a slope grade based on the slope value, and applying a basic compensation to the electric torque and the braking force based on the road surface type and the slope grade; Monitoring a slope change amount of a change in the slope, and applying an additional compensation to the electric torque and the braking force based on the slope change amount; Obtaining front-rear direction pressure data and calculating a front-rear pressure difference, determining a front-rear center of gravity shift direction based on the front-rear pressure difference, and applying a load shift torque compensation to an opposite side of the front-rear center of gravity shift direction; Obtaining left-right direction pressure data and calculating a left-right pressure difference, determining a left-right center of gravity shift direction based on the left-right pressure difference, and applying a load shift torque compensation to an inner side wheel during a turn in combination with a vehicle speed; Monitoring a pressure data change rate, and adjusting the load shift torque compensation based on the pressure data change rate.

[0020] Specifically, the self-balancing scooter uses an inertial measurement unit (IMU) consisting of a three-axis gyroscope, a three-axis accelerometer, and a three-axis magnetometer, installed at the center of gravity of the scooter. This IMU collects attitude data at a high frequency of over 100Hz. After eliminating sensor noise using a Kalman filter and correcting zero-drift errors using a temperature compensation algorithm, the angle between the road surface and the horizontal plane (i.e., the road slope) is calculated by combining the vertical component of gravitational acceleration with the pitch angle data output by the IMU. A fixed acquisition period of 10ms-20ms is set to continuously cache the slope values ​​collected each time. The slope value of the current period is subtracted from the slope value of the previous collection period to obtain the slope change in a single period. Simultaneously, slope changes from multiple consecutive periods are cached for continuous monitoring of slope changes. Abnormal data exceeding a reasonable range is discarded based on a threshold judgment to avoid misjudgment. At least one strain gauge pressure sensor is symmetrically placed at the front and rear positions on the underside of the foot pedal. The sensors are in close contact with the force-bearing surface of the foot pedal and connected to a signal amplification circuit. Pressure signals from the front and rear areas are collected at a frequency synchronized with the IMU. After filtering to remove electromagnetic interference from the motor, all pressure signals from the front are recorded. The average value collected by the sensors is taken as the front pressure data, and the average value collected by all pressure sensors on the rear side is taken as the rear pressure data. The front pressure data is then subtracted from the rear pressure data to obtain the front-to-back pressure difference. At least one strain gauge pressure sensor is placed symmetrically on each side of the lower surface of the foot pedal. The sensors are installed in a staggered manner with the front and rear pressure sensors to avoid force interference. After signal amplification and filtering, the average value collected by all pressure sensors on the left side is taken as the left pressure data, and the average value collected by all pressure sensors on the right side is taken as the right pressure data. The left pressure data is then subtracted from the right pressure data to obtain the left-to-right pressure difference. By setting a time interval of 5ms-10ms, the values ​​of the front-to-back pressure difference and the left-to-right pressure difference are extracted at the beginning and end of the time interval. The difference between the two values ​​is calculated (the value at the end time minus the value at the beginning time). This difference is then divided by the corresponding time interval to obtain the rate of change of the front-to-back pressure difference and the left-to-right pressure difference per unit time, which corresponds to the rate of change of pressure data in the front-to-back direction and the left-to-right direction, respectively, thus realizing real-time monitoring of the rate of change of pressure data.

[0021] Understandably, by acquiring road slope values ​​and classifying road types and slope levels, targeted basic torque or braking force compensation is applied. Simultaneously, by monitoring slope changes and applying additional compensation when road types or slopes change abruptly, the problem of insufficient power uphill and loss of speed downhill for the self-balancing scooter under different slope conditions is effectively solved. By collecting front, rear, left, and right pressure data and calculating pressure differences, the direction of center of gravity shift is accurately determined, and load torque compensation is applied to the opposite side. Furthermore, when turning, the load torque compensation on the left and right sides is increased proportionally based on the vehicle speed threshold, which can offset the risk of posture imbalance caused by center of gravity shift and centrifugal force during high-speed turns. By monitoring the rate of change of pressure data, when the load change threshold is exceeded, the load torque compensation in the front, rear, left, and right directions is increased using an emergency compensation ratio. This allows for rapid response to load change scenarios, avoiding vehicle swaying or loss of control caused by sudden load changes. Overall, the self-balancing scooter achieves precise control under complex conditions such as slope changes, center of gravity shifts, turning, and load changes, significantly improving driving stability and safety.

[0022] In some embodiments of this application, determining the road surface type and slope grade based on the slope value includes: When the slope value is greater than zero and the slope value is greater than the slope threshold, the road surface type is uphill. When the slope value is less than zero and the slope value is less than the negative of the slope threshold, the road surface type is downhill. When the absolute value of the slope is less than or equal to the slope threshold, the road surface type is flat. When the absolute value of the slope is within the first slope range, the slope grade is gentle slope; When the absolute value of the slope is within the second slope range, the slope grade is medium slope. When the absolute value of the slope is in the third slope range, the slope level is steep.

[0023] Specifically, the slope threshold is a critical slope value used by the self-balancing scooter to distinguish between flat roads and uphill / downhill roads. Its setting requires comprehensive consideration of core parameters such as the scooter's body structure, motor output capacity, and center of gravity distribution. It is determined through numerous stable driving tests under various road conditions to ensure that the scooter can travel stably without additional slope compensation when the slope value does not exceed this threshold; if the threshold is exceeded, the corresponding slope compensation strategy must be activated. The first slope range is the absolute value range of slopes defined by the self-balancing scooter for gentle slopes. The value range of this range needs to match the scooter's low-load slope compensation logic and is determined based on test data such as motor torque output efficiency and vehicle posture stability range under gentle slope conditions. The compensation amount for slopes within the first range must meet the balance requirements without causing overcompensation. The second slope range is the absolute value range of the slope defined by the self-balancing scooter for medium-slope conditions. Its value range lies between the first and third slope ranges. It needs to be set based on test data such as motor load capacity and braking force adjustment range under medium-slope conditions to ensure that the corresponding compensation strategy can adapt to the force changes brought about by medium slopes. The third slope range is the absolute value range of the slope defined by the self-balancing scooter for steep slopes. Its value is higher than the first and second slope ranges. It needs to be determined based on extreme working condition test data such as maximum motor torque output and braking force limit under steep slope conditions to ensure that the corresponding compensation strategy can cope with steep slopes. The significant force changes caused by the scooter's instability are addressed by maintaining vehicle stability. The slope value is obtained by high-frequency acquisition of the scooter's pitch angle data using an inertial measurement unit (IMU) mounted on the scooter, combined with the gravitational acceleration component. During data acquisition, filtering algorithms are used to eliminate sensor noise, and temperature compensation algorithms correct for zero-drift errors to ensure data accuracy. The slope threshold is determined through multiple stable driving tests at test sites with varying slopes, recording the maximum slope at which the scooter can maintain stable driving without slope compensation. This is then combined with statistical analysis to remove outliers and determine the final critical value. The first slope range involves conducting gentle slope tests with different slope gradients, recording the scooter's performance. By analyzing attitude stability data and motor load data at various gradient slopes, the absolute value range of slopes that allow for stable driving without significant adjustments to compensation parameters is selected as the first slope range. The second slope range involves conducting medium-slope tests within the slope range between gentle and steep slopes to analyze changes in the compensation requirements and motor output efficiency of the self-balancing vehicle under different slopes, determining the absolute value range of slopes requiring moderate-intensity compensation, which is also selected as the second slope range. The third slope range involves conducting steep-slope tests at high gradient slopes to test the stable driving limit of the self-balancing vehicle at extreme slopes, recording the absolute value range of slopes requiring maximum-intensity compensation to maintain stability, which is also selected as the third slope range.

[0024] Specifically, a slope threshold of 2° is set. The first slope range is greater than 0° and less than or equal to 5°, the second slope range is greater than 5° and less than or equal to 15°, and the third slope range is greater than 15°. When the slope value collected by the self-balancing scooter is 3° (greater than zero and greater than 2°), the road surface type is determined to be uphill, and its absolute slope value of 3° falls within the first slope range, so the slope level is gentle. When the collected slope value is -8° (less than zero and less than -2°), the road surface type is determined to be downhill, and its absolute slope value of 8° falls within the second slope range, so the slope level is medium. When the collected slope value is... When the slope value is 1° (absolute value less than or equal to 2°), the road surface type is determined to be flat. Its absolute slope value of 1° is in the first slope range, but since the road surface type is flat, it only needs to be processed according to the logic corresponding to flat road surfaces. When the collected slope value is 18° (greater than zero and greater than 2°), the road surface type is determined to be uphill. Its absolute slope value of 18° is in the third slope range, so the slope level is steep. When the collected slope value is -3° (less than zero and less than -2°), the road surface type is determined to be downhill. Its absolute slope value of 3° is in the first slope range, so the slope level is gentle.

[0025] Understandably, by differentiating flat, uphill, and downhill road surface types through slope thresholds, and further subdividing them into gentle, medium, and steep slope levels through three slope intervals, a clear and quantifiable basis for subsequent targeted slope compensation strategies is provided. This avoids the drawbacks of using a uniform compensation strategy for different road conditions, enabling slope compensation to accurately match the actual working conditions of the current road surface and improving the targeting and rationality of slope compensation.

[0026] In some embodiments of this application, when applying basic compensation to the electric torque and braking force based on the road surface type and the slope grade, the following are included: When the road surface type is uphill, the basic torque compensation ratio corresponding to the slope level is extracted from the preset slope-torque compensation relationship, and compensation is applied to the electric torque according to the basic torque compensation ratio. When the road surface is downhill, the basic braking compensation ratio corresponding to the slope level is extracted from the preset slope-braking force compensation relationship, and the braking force is compensated according to the basic braking compensation ratio. When the road surface is flat, the current electric torque and braking force remain unchanged.

[0027] Specifically, the preset slope-torque compensation relationship is the corresponding association data stored in the controller of the self-balancing scooter, showing the slope level and the required torque compensation parameters for uphill conditions. It includes torque compensation rules for each level of gentle, medium, and steep slopes, used to quickly match an appropriate torque compensation scheme based on the determined slope level, ensuring that the motor's output torque can adapt to the slope resistance when going uphill. The basic torque compensation ratio is a specific ratio value in the preset slope-torque compensation relationship that uniquely corresponds to a specific slope level. This ratio directly determines the percentage of additional torque that the motor needs to add on top of the basic output torque when going uphill. Different slope levels correspond to different ratio values, with higher slope levels generally having a larger ratio. The preset slope-torque compensation ratio... The power compensation relationship is the corresponding data stored in the controller of the self-balancing scooter regarding the slope level and the required braking force compensation parameters on downhill roads. It includes braking force compensation rules for each level of gentle, medium, and steep slopes, used to quickly match an appropriate braking force compensation scheme based on the determined slope level, preventing excessive speed when going downhill. The basic braking compensation ratio is a specific ratio value in the preset slope-braking force compensation relationship that uniquely corresponds to a specific slope level. This ratio directly determines the proportion of additional braking force required on top of the basic braking force when going downhill. Different slope levels correspond to different ratio values, with higher slope levels generally having larger ratios. The electric torque is the output of the self-balancing scooter's motor to drive the wheels after power is applied. The torque is the core power that propels the self-balancing scooter uphill or maintains its movement. Its magnitude can be adjusted by the controller according to the compensation ratio. The braking force is the force used by the self-balancing scooter to resist wheel rotation and reduce speed. It can be achieved through the reverse torque output of the motor or a dedicated braking mechanism. Its magnitude can be adjusted by the controller according to the compensation ratio and is used to control the speed and prevent loss of control when going downhill. The preset slope-torque compensation relationship is obtained through the following operations: Select uphill test sites with different gradients, let the self-balancing scooter drive at different stable speeds at each gradient, collect the additional torque data required to maintain the balance of the scooter in real time through the torque sensor, remove abnormal data, and establish a correlation table or function between each slope level and the corresponding required torque compensation. The system is stored in the balance scooter controller; the basic torque compensation ratio is obtained through the following operations: extract the specific torque compensation ratio values ​​corresponding to each slope level (gentle, medium, and steep) from the established preset slope-torque compensation relationship, with each slope level corresponding to a unique basic torque compensation ratio; the preset slope-braking force compensation relationship is obtained through the following operations: select downhill test sites with different gradients, let the balance scooter travel at different initial speeds at each gradient, collect the additional braking force data required to maintain vehicle stability and control speed in real time through the braking force sensor, remove abnormal data, establish a correlation table or function relationship between each slope level and the corresponding required braking force compensation, and store it in the balance scooter controller;The basic braking compensation ratio is obtained through the following operations: From the established preset slope-braking force compensation relationship, the specific braking force compensation ratio values ​​corresponding to each slope level (gentle, medium, and steep) are extracted. Each slope level corresponds to a unique basic braking compensation ratio. The electric torque is obtained through the following operations: The balance scooter controller calculates the basic output torque based on the current driving state, and then, combined with the extracted basic torque compensation ratio, calculates the total output torque using a torque adjustment algorithm. A control command is sent to the motor, which then powers on and outputs the corresponding electric torque. The braking force is obtained through the following operations: The balance scooter controller calculates the basic braking force based on the current driving state, and then, combined with the extracted basic braking compensation ratio, calculates the total braking force using a braking force adjustment algorithm. A control command is sent to the braking actuator (motor reverse drive or dedicated braking device), which then generates the corresponding braking force.

[0028] Specifically, the preset slope-torque compensation relationship is set as follows: 10% for gentle slopes, 25% for medium slopes, and 40% for steep slopes. The preset slope-braking force compensation relationship is set as follows: 15% for gentle slopes, 30% for medium slopes, and 50% for steep slopes. When the balance scooter determines that the road surface type is uphill and the slope level is medium, 25% of the basic torque compensation ratio is extracted from the preset slope-torque compensation relationship and applied to the current basic electric torque of the motor. The motor output electric torque is controlled according to the calculation result of basic electric torque × (1 + 25%). When the road surface type is determined to be downhill and the slope level is steep, 50% of the basic braking compensation ratio is extracted from the preset slope-braking force compensation relationship and applied to the current basic braking force. The braking force generated by the braking actuator is controlled according to the calculation result of basic braking force × (1 + 50%). When the road surface type is determined to be flat, the current electric torque output by the motor and the braking force generated by the braking actuator remain unchanged.

[0029] Understandably, by applying targeted compensation to the base torque or braking force, the electric torque is increased by matching the base torque compensation ratio according to the slope level when going uphill, and the braking force is increased by matching the base braking compensation ratio according to the slope level when going downhill. On flat roads, the power braking remains unchanged. This effectively solves the common problems of insufficient power when going uphill and loss of speed when going downhill in traditional self-balancing vehicles under different slope conditions, and significantly improves the driving stability of self-balancing vehicles under various basic slope conditions.

[0030] In some embodiments of this application, when applying additional compensation to the electric torque and braking force based on the slope change amount, the following are included: When the road surface type changes before and after the slope value changes, basic compensation is applied to the electric torque and braking force based on the current road surface type and the current slope level.

[0031] Understandably, for scenarios involving abrupt changes in road surface type, it is clarified that when a change in slope value leads to a change in road surface type, basic compensation must be reapplied based on the new road surface type and slope level. This ensures that the compensation strategy of the self-balancing vehicle can be switched in a timely manner during the transition phase of road surface type (such as from flat to uphill, or from uphill to downhill), avoiding the problem of power or braking mismatch during the transition phase caused by the lag in compensation strategy, and improving the adaptability of the self-balancing vehicle to the working conditions of abrupt changes in road surface type.

[0032] In some embodiments of this application, when applying additional compensation to the electric torque and braking force based on the slope change amount, the method further includes: When the slope change exceeds the slope abrupt change threshold and the road surface type is always uphill, then based on the basic torque compensation ratio, additional electric torque compensation is added according to a preset extra torque compensation ratio. When the slope change is greater than the slope change threshold and the road surface type is always downhill, braking force compensation is added according to the preset additional braking compensation ratio based on the basic braking compensation ratio. When the slope change is less than or equal to the slope change threshold, the current electric torque and braking force remain unchanged.

[0033] Specifically, the slope change is the difference between the road slope values ​​acquired by the self-balancing scooter over two consecutive data collection periods. This value can be positive or negative; a positive value indicates an increase in slope, and a negative value indicates a decrease. It directly reflects the magnitude and trend of the slope change and is the core basis for determining whether additional slope compensation is needed. The slope abrupt change threshold is a pre-set critical slope change value used by the self-balancing scooter to distinguish between normal slope changes and abrupt changes. When the actual slope change exceeds this threshold, it is determined to be a sudden slope change, requiring the activation of additional compensation strategies; otherwise, it is treated as a normal slope change. The preset additional torque compensation ratio is a pre-set ratio for the self-balancing scooter to handle abrupt slope changes on uphill roads. The system stores an additional torque compensation ratio on top of the base torque compensation ratio. Different uphill slope levels correspond to different ratios to compensate for the additional resistance caused by sudden slope changes. The preset additional braking compensation ratio is a pre-stored braking force compensation ratio on top of the base braking compensation ratio, designed for downhill slopes with sudden slope changes. Different downhill slope levels correspond to different ratios to address the risk of increased speed due to sudden slope changes. Slope changes are obtained through the following operation: the system continuously acquires road slope values ​​according to a set collection cycle, and subtracts the slope value of the previous collection cycle from the current collection cycle's slope value. The slope value is calculated by taking the slope difference between two data collections; this difference is the slope change. The sign of the slope change is recorded to clarify the slope change trend. The slope abrupt change threshold is obtained through the following steps: Select uphill and downhill test sites with different slope levels to simulate slope abrupt change scenarios of varying magnitudes. Allow the self-balancing scooter to drive in each scenario, recording the minimum slope change threshold required for the scooter to maintain stable driving. After removing abnormal test data, the statistical analysis results of the threshold values ​​for each scenario are used as the slope abrupt change threshold. The preset additional torque compensation ratio is obtained through the following steps: In the uphill slope abrupt change test, for each slope level (gentle, medium, and steep), the following steps are performed: Test the stability of the self-balancing scooter under different additional torque compensation ratios, and record the ratio values ​​that enable the scooter to quickly recover stability without overcompensation at each level. Storing these values ​​in association with the corresponding slope level forms a preset additional torque compensation ratio. The preset additional braking compensation ratio is obtained through the following operation: In the downhill gradient change test, for each slope level (gentle, medium, and steep), test the speed control effect of the self-balancing scooter under different additional braking compensation ratios, and record the ratio values ​​that enable the self-balancing scooter to effectively control its speed without the risk of excessive braking at each level. Storing these values ​​in association with the corresponding slope level forms a preset additional braking compensation ratio.

[0034] Specifically, the slope change threshold is set to 5°, the preset additional torque compensation ratio is 10% for gentle slopes, 15% for medium slopes, and 20% for steep slopes, and the preset additional braking compensation ratio is 12% for gentle slopes, 18% for medium slopes, and 25% for steep slopes. When the self-balancing vehicle determines that the road surface type before and after the change is uphill, the slope change is 6° (greater than the slope change threshold of 5°), and the current slope level is medium slope, an additional 15% of the preset additional torque compensation ratio is added to the already applied 25% basic torque compensation ratio, resulting in a total torque compensation ratio of 40%. When the road surface type changes and both the slope is downhill, the slope change is 7° (greater than the 5° slope change threshold), and the current slope level is steep, an additional 25% of the preset extra braking compensation is added on top of the already applied 50% basic braking compensation ratio, for a total braking compensation ratio of 75%. When the slope change is 3° (less than or equal to the 5° slope change threshold), no additional torque compensation or extra braking compensation is applied, regardless of whether the current road surface type is uphill, downhill, or flat, and the current electric torque and braking force remain unchanged.

[0035] Understandably, in addition to basic slope compensation, an extra compensation strategy is designed for scenarios with sudden slope changes. When the slope change exceeds the sudden change threshold and the road surface type remains unchanged, extra torque compensation is added for uphill conditions and extra braking compensation is added for downhill conditions. This further enhances the ability to cope with extreme conditions with sudden slope changes, effectively solving the problem of sudden drop in uphill power and sudden increase in downhill speed caused by insufficient basic compensation when the slope changes. This significantly improves the driving safety of the self-balancing vehicle under conditions of drastic slope changes.

[0036] In some embodiments of this application, when determining the forward / backward offset direction of the center of gravity based on the forward / backward pressure difference and applying a heavy load torque compensation to the opposite side of the forward / backward offset direction, the method includes: The pressure difference between the front and rear sides is equal to the difference between the pressure value on the front side and the pressure value on the rear side. When the pressure difference between the front and rear is greater than zero, it is determined that the center of gravity has shifted to the front and a heavy load torque compensation is applied to the rear. When the pressure difference between the front and rear is less than zero, it is determined that the center of gravity has shifted to the rear and a heavy load torque compensation is applied to the front. When the pressure difference between the front and rear is zero, no heavy load torque compensation is applied. The amount of load torque compensation is proportional to the absolute value of the pressure difference between the front and rear.

[0037] Specifically, load torque compensation is the torque output to the opposite side of the center of gravity shift on the self-balancing scooter to counteract the impact of the center of gravity shift on driving stability. It is applied only when a center of gravity shift is detected, and not when there is no shift. The amount of compensation is positively correlated with the absolute value of the front-to-rear pressure difference corresponding to the center of gravity shift. It directly acts on the wheel drive system, correcting the vehicle's posture by precisely adjusting the torque output on the corresponding side, thus preventing vehicle tilting or loss of control due to center of gravity shift. Load torque compensation is achieved through the following steps: First, pressure sensors placed in the front and rear areas of the foot pedals collect the front and rear pressure values ​​respectively. The collected pressure... The force signal is filtered to eliminate electromagnetic interference from the motor and environmental noise. The front-to-rear pressure difference is obtained by calculating the difference between the front and rear pressure values. The direction of the center of gravity shift is determined by the sign of the front-to-rear pressure difference. Based on the preset correspondence between the absolute value of the pressure difference and the torque compensation amount (this relationship is established through test data of different degrees of center of gravity shift to clarify the torque compensation amount corresponding to different absolute values ​​of pressure difference), the torque compensation amount corresponding to the current absolute value of the front-to-rear pressure difference is matched. Finally, the balance vehicle controller sends a torque control command to the motor on the opposite side of the shift direction, and the motor outputs the corresponding load torque compensation according to the command.

[0038] Specifically, when the front pressure value is set to 60N and the rear pressure value to 40N, the front-to-rear pressure difference = 60N - 40N = 20N (greater than zero). The center of gravity is determined to be shifted forward. Based on the preset correspondence of "load torque compensation = absolute value of front-to-rear pressure difference × 0.4N・m / N", load torque compensation is applied to the rear, with a compensation amount of 20N × 0.4N・m / N = 8N・m. When the front pressure value is set to 30N and the rear pressure value to 55N, the front-to-rear pressure difference = 30N - 55N = -25N (less than zero). The center of gravity is determined to be shifted backward, and load torque compensation is applied to the front, with a compensation amount of |-25N| × 0.4N・m / N = 10N・m. When the front pressure value is set to 45N and the rear pressure value to 45N, the front-to-rear pressure difference = 0N, and no load torque compensation is applied.

[0039] Understandably, by collecting pressure data in the front and rear directions and calculating the pressure difference, the direction of the center of gravity shift can be accurately determined. Furthermore, by applying a heavy load torque to the opposite side of the shift in a manner proportional to the absolute value of the pressure difference, accurate perception and reverse compensation of the occupant's center of gravity shift can be achieved. This effectively counteracts the risk of the vehicle tilting forward or backward due to the shift of the center of gravity, solves the problem of posture imbalance caused by the forward and backward movement of the center of gravity in traditional self-balancing vehicles, and improves the driving stability of the self-balancing vehicle when the occupant's center of gravity changes dynamically.

[0040] In some embodiments of this application, when determining the left-right offset direction of the center of gravity based on the left-right pressure difference, and applying a heavy torque compensation to the inner wheel during turning in combination with vehicle speed, the following steps are included: The pressure difference between the left and right sides is equal to the difference between the pressure value on the left side and the pressure value on the right side. When the pressure difference between the left and right sides is greater than zero, it is determined that the center of gravity has shifted to the left, and a heavy load torque compensation is applied to the right. When the pressure difference between the left and right sides is less than zero, it is determined that the center of gravity has shifted to the right, and a heavy load torque compensation is applied to the left side. When the pressure difference between the left and right sides is zero, no additional torque compensation is applied. The amount of load torque compensation is proportional to the absolute value of the pressure difference between the front and rear.

[0041] Specifically, when the left pressure value is set to 50N and the right pressure value to 30N, the left-right pressure difference = 50N - 30N = 20N (greater than zero), indicating a shift of the center of gravity to the left. Based on the preset correspondence of "load torque compensation = absolute value of front-rear pressure difference × 0.3N・m / N", load torque compensation is applied to the right, with a compensation amount of 20N × 0.3N・m / N = 6N・m. When the left pressure value is set to 25N and the right pressure value to 55N, the left-right pressure difference = 25N - 55N = -30N (less than zero), indicating a shift of the center of gravity to the right. Load torque compensation is applied to the left, with a compensation amount of |-30N| × 0.3N・m / N = 9N・m. When the left pressure value is set to 40N and the right pressure value to 40N, the left-right pressure difference = 0N, and no load torque compensation is applied.

[0042] Understandably, by collecting pressure data in the left and right directions and calculating the pressure difference, the direction of the center of gravity shifts to the left and right is accurately determined. Similarly, in a manner proportional to the absolute value of the pressure difference, a heavy load torque is applied to the opposite side of the shift, thereby achieving accurate perception and reverse compensation of the occupant's left and right center of gravity shift. This effectively offsets the risk of vehicle tilt caused by the left and right center of gravity shift, providing a foundation for compensation strategies under subsequent turning conditions and improving the driving stability of the self-balancing vehicle when the occupant's left and right center of gravity shifts.

[0043] In some embodiments of this application, when determining the left-right offset direction of the center of gravity based on the left-right pressure difference, and applying a heavy torque compensation to the inner wheel in combination with the vehicle speed during turning, the method further includes: When the vehicle speed exceeds the vehicle speed threshold, the load torque compensation on the left and right sides is increased according to the ratio of the vehicle speed divided by the vehicle speed threshold.

[0044] Specifically, the speed threshold is a preset critical speed value for the self-balancing scooter to determine whether to increase the load torque compensation on the left and right sides when turning. Its setting needs to be combined with parameters such as the wheelbase, center of gravity height, and turning stability limit of the self-balancing scooter. When the actual speed during turning does not exceed the threshold, the existing load torque compensation on the left and right sides can meet the balance requirements of the scooter. When the actual speed exceeds the threshold, the compensation amount needs to be increased proportionally to offset the centrifugal force caused by the higher speed, so as to avoid rollover or loss of control during turning. The speed threshold is obtained through the following specific operations: Select test sites with different curve radii (such as 3m, 5m, 8m), and let the self-balancing scooter turn at an increasing speed at each curve radius. The body tilt angle is monitored in real time by the attitude sensor, and the force distribution on the left and right wheels is monitored by the pressure sensor. Record the maximum speed at which the self-balancing scooter can maintain stable turning without increasing the load torque compensation at each curve radius. Statistical analysis is performed on the test data at different curve radii, and abnormal data caused by differences in road friction coefficient and sensor errors are eliminated. Finally, the critical speed that is suitable for most common turning scenarios is determined as the speed threshold.

[0045] Specifically, the vehicle speed threshold is set to 10 km / h, and the established base amount of load torque compensation on the left and right sides is 6 N·m (applied to the right side when the center of gravity shifts to the left). When the actual vehicle speed during a turn is 15 km / h (greater than the 10 km / h speed threshold), the load torque compensation on the left and right sides is increased by the ratio of the vehicle speed divided by the speed threshold (15 km / h ÷ 10 km / h = 1.5), and the adjusted load torque compensation is 6 N·m × 1.5 = 9 N·m. When the actual vehicle speed during a turn is 8 km / h (less than the 10 km / h speed threshold) or 10 km / h (equal to the 10 km / h speed threshold), the load torque compensation on the left and right sides is not adjusted, and the base compensation amount of 6 N·m remains unchanged.

[0046] Understandably, increasing the load torque compensation on the left and right sides according to the ratio of vehicle speed to threshold effectively offsets the additional tilt risk caused by centrifugal force when turning at high speed, solves the risk of rollover caused by centrifugal force when traditional self-balancing scooters turn at high speed, and significantly improves the driving safety of self-balancing scooters in turning conditions, especially in high-speed turning conditions.

[0047] In some embodiments of this application, adjusting the load torque compensation based on the rate of change of the pressure data includes: When the rate of change of the pressure data exceeds the load mutation threshold, the load torque compensation in the front-to-back and left-to-right directions is increased by using the emergency compensation ratio.

[0048] Specifically, the pressure data change rate is the amount of change in the front-to-back or left-to-right pressure data of the self-balancing scooter per unit time. Its unit is pressure units / time units, directly reflecting how fast the pressure data changes. It is a core indicator for determining whether the self-balancing scooter has experienced a sudden load change (such as rapid movement of the rider's body or sudden increase / decrease in load). The faster the change rate, the more severe the load change. The load change threshold is a preset critical pressure data change rate value used by the self-balancing scooter to distinguish between normal pressure changes and load changes. When the actual pressure data change rate exceeds this threshold, it is determined that a load change has occurred, and an emergency compensation strategy needs to be activated. If it does not exceed the threshold, it is processed according to the normal load torque compensation logic. The emergency compensation ratio is a fixed ratio value preset by the self-balancing scooter for load change scenarios, used to increase the load torque compensation in the front-to-back and left-to-right directions. Its magnitude must match the vehicle stability requirements during a load change to ensure that the risk of posture imbalance caused by the change is offset by rapidly increasing the compensation amount. The pressure data change rate is obtained through the following specific operations: The self-balancing scooter continuously collects front-to-back and left-to-right pressure data at set fixed time intervals (e.g., 5ms-10ms), and calculates the difference between the front and rear pressure data in each time interval (current...). The pressure change rate is obtained by subtracting the previous value from the current value and the difference between the left and right pressure data (current value minus previous value), and then dividing each difference by the corresponding time interval. The load change threshold is obtained through the following specific operations: simulating different types of load change scenarios (such as rapid forward / backward tilting of the occupant, rapid left / right displacement, and sudden application of additional load), allowing the self-balancing scooter to drive in each scenario, monitoring whether the scooter is unbalanced through attitude sensors, and recording the maximum pressure change rate in each scenario where the scooter can just maintain stability without emergency compensation. The data from multiple tests is then analyzed. Statistical analysis was conducted to eliminate outliers caused by sensor errors and environmental interference, and the critical value was finally determined as the load change threshold. The emergency compensation ratio was obtained through the following specific operations: In the determined load change scenario, for different pressure data change rates (exceeding the load change threshold), the attitude recovery effect of the self-balancing scooter under different emergency compensation ratios was tested. The ratio values ​​that allowed the scooter to quickly recover stability without overcompensation (such as violent shaking or reverse tilting) in each scenario were recorded. After multiple verifications, a unified emergency compensation ratio or graded emergency compensation ratios were determined and stored in the self-balancing scooter controller.

[0049] Specifically, the load change threshold is set to 5 N / s, the emergency compensation ratio is 20%, and the determined load torque compensation amounts in the front-rear direction are 10 N·m and in the left-right direction are 9 N·m. When the rate of change of the pressure data in the front-rear direction is detected to be 7 N / s (greater than the load change threshold of 5 N / s), the load torque compensation in the front-rear and left-right directions is increased by 20% using the emergency compensation ratio. The adjusted load torque compensation amount in the front-rear direction is 10 N·m × (1 + 20%) = 12 N·m, and the adjusted load torque compensation amount in the left-right direction is 9 N·m × (1 + 20%) = 10.8 N·m. When the rate of change of the pressure data in the left-right direction is detected to be 4 N / s (less than or equal to the load change threshold of 5 N / s), the emergency compensation is not activated, and the load torque compensation amounts in the front-rear direction of 10 N·m and in the left-right direction of 9 N·m remain unchanged.

[0050] Understandably, in response to sudden load changes, by monitoring the rate of change of pressure data, when the rate exceeds the load change threshold, the load torque compensation in the front-to-back and left-to-right directions is increased simultaneously using the emergency compensation ratio. This enables a rapid response to sudden load changes such as rapid movement of passengers and sudden increases or decreases in load, effectively offsetting the risk of instantaneous shaking or loss of control of the vehicle caused by sudden load changes. It solves the problem of delayed response of traditional self-balancing vehicles to sudden load changes and improves the attitude control capability of self-balancing vehicles under dynamic load change conditions.

[0051] In some embodiments of this application, when adjusting the load torque compensation based on the rate of change of the pressure data, the method further includes: When the rate of change of the pressure data is less than or equal to the load change threshold, the current load torque compensation remains unchanged.

[0052] Understandably, it was clarified that when the rate of change of pressure data recovers to below the load mutation threshold, the current load torque compensation should remain unchanged. This avoids secondary attitude imbalance caused by blindly adjusting the compensation strategy during the load mutation recovery phase, ensuring the integrity and closed-loop nature of the load mutation compensation strategy, and further improving the stability and reliability of the attitude control of the self-balancing vehicle under load mutation conditions.

[0053] It should be noted that: Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0054] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of this application and form different embodiments.

[0055] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling a self-balancing scooter, characterized in that, include: Obtain the slope value of the road surface, determine the road surface type and slope grade based on the slope value, and apply basic compensation to the electric torque and braking force based on the road surface type and the slope grade; Monitor the amount of slope change when the slope changes, and apply additional compensation to the electric torque and braking force based on the amount of slope change; Acquire front-to-back pressure data and calculate the front-to-back pressure difference. Based on the front-to-back pressure difference, determine the front-to-back offset direction of the center of gravity and apply a load torque compensation to the opposite side of the front-to-back offset direction. Acquire left and right pressure data and calculate the left and right pressure difference. Based on the left and right pressure difference, determine the left and right offset direction of the center of gravity. When turning, apply heavy load torque compensation to the inner wheel in combination with the vehicle speed. Monitor the rate of change of pressure data and adjust the load torque compensation based on the rate of change of pressure data.

2. The self-balancing scooter control method according to claim 1, characterized in that, When determining the road surface type and slope grade based on the slope value, the following are included: When the slope value is greater than zero and the slope value is greater than the slope threshold, the road surface type is uphill. When the slope value is less than zero and the slope value is less than the negative of the slope threshold, the road surface type is downhill. When the absolute value of the slope is less than or equal to the slope threshold, the road surface type is flat. When the absolute value of the slope is within the first slope range, the slope grade is gentle slope; When the absolute value of the slope is within the second slope range, the slope grade is medium slope. When the absolute value of the slope is in the third slope range, the slope level is steep.

3. The self-balancing scooter control method according to claim 2, characterized in that, When applying basic compensation to electric torque and braking force based on the road surface type and the slope grade, it includes: When the road surface type is uphill, the basic torque compensation ratio corresponding to the slope level is extracted from the preset slope-torque compensation relationship, and compensation is applied to the electric torque according to the basic torque compensation ratio. When the road surface is downhill, the basic braking compensation ratio corresponding to the slope level is extracted from the preset slope-braking force compensation relationship, and the braking force is compensated according to the basic braking compensation ratio. When the road surface is flat, the current electric torque and braking force remain unchanged.

4. The self-balancing scooter control method according to claim 3, characterized in that, When applying additional compensation to the electric torque and braking force based on the slope change, it includes: When the road surface type changes before and after the slope value changes, basic compensation is applied to the electric torque and braking force based on the current road surface type and the current slope level.

5. The self-balancing scooter control method according to claim 4, characterized in that, When applying additional compensation to the electric torque and braking force based on the slope transformation amount, it also includes: When the slope change exceeds the slope abrupt change threshold and the road surface type is always uphill, then based on the basic torque compensation ratio, additional electric torque compensation is added according to a preset extra torque compensation ratio. When the slope change is greater than the slope change threshold and the road surface type is always downhill, braking force compensation is added according to the preset additional braking compensation ratio based on the basic braking compensation ratio. When the slope change is less than or equal to the slope change threshold, the current electric torque and braking force remain unchanged.

6. The self-balancing scooter control method according to claim 5, characterized in that, When determining the direction of the center of gravity shift based on the front-to-back pressure difference, and applying a heavy load torque compensation to the opposite side of the front-to-back shift direction, the following steps are included: The pressure difference between the front and rear sides is equal to the difference between the pressure value on the front side and the pressure value on the rear side. When the pressure difference between the front and rear is greater than zero, it is determined that the center of gravity has shifted to the front and a heavy load torque compensation is applied to the rear. When the pressure difference between the front and rear is less than zero, it is determined that the center of gravity has shifted to the rear and a heavy load torque compensation is applied to the front. When the pressure difference between the front and rear is zero, no heavy load torque compensation is applied. The amount of load torque compensation is proportional to the absolute value of the pressure difference between the front and rear.

7. The self-balancing scooter control method according to claim 6, characterized in that, Based on the left and right pressure difference, the direction of the center of gravity shifts left and right. When turning, and in conjunction with the vehicle speed, when applying a heavy load torque compensation to the inner wheel, the following is included: The pressure difference between the left and right sides is equal to the difference between the pressure value on the left side and the pressure value on the right side. When the pressure difference between the left and right sides is greater than zero, it is determined that the center of gravity has shifted to the left, and a heavy load torque compensation is applied to the right. When the pressure difference between the left and right sides is less than zero, it is determined that the center of gravity has shifted to the right, and a heavy load torque compensation is applied to the left side. When the pressure difference between the left and right sides is zero, no additional torque compensation is applied. The amount of load torque compensation is proportional to the absolute value of the pressure difference between the front and rear.

8. A self-balancing scooter control method according to claim 7, characterized in that, Based on the left and right pressure difference, the direction of the center of gravity shifts left and right. When applying a heavy load torque to the inner wheel during a turn, combined with the vehicle speed, the following additional steps are included: When the vehicle speed exceeds the vehicle speed threshold, the load torque compensation on the left and right sides is increased according to the ratio of the vehicle speed divided by the vehicle speed threshold.

9. A self-balancing scooter control method according to claim 8, characterized in that, When adjusting the load torque compensation based on the rate of change of the pressure data, the following steps are included: When the rate of change of the pressure data exceeds the load mutation threshold, the load torque compensation in the front-to-back and left-to-right directions is increased by using the emergency compensation ratio.

10. A self-balancing scooter control method according to claim 9, characterized in that, When adjusting the load torque compensation based on the rate of change of the pressure data, the following methods are also included: When the rate of change of the pressure data is less than or equal to the load change threshold, the current load torque compensation remains unchanged.

Images