Steering angle-based steering control method and cargo handling equipment

Abstract

The invention discloses a steering control method based on a steering angle and cargo handling equipment, relates to the technical field of steering control, and solves the technical problems that the flexibility of a chassis of the cargo handling equipment is insufficient, the safety of the turning process of the chassis is influenced, and the operation capacity in a narrow space is insufficient. The steering angle is collected in real time, and the speed parameters, namely the target speed and the acceleration, are calculated according to the steering angle and the basic parameters; the driving speed is adjusted through the acceleration, so that the driving speed follows the target speed; moreover, data collection and calculation are carried out again every other sampling period, and the acceleration and the driving speed are adjusted in time. According to the method, the calculation mode of the acceleration is determined by comparing the driving speed with the target speed, and then the driving speed is adjusted according to the acceleration, so that it is guaranteed that the driving speed follows the target speed, safety and stability of the adjusting process are guaranteed, rollover in the turning process can be avoided, and the overall safety of steering control is improved.

Description

Technical Field

[0001] The present application belongs to the field of steering control, and specifically to a steering control method and cargo handling equipment based on a steering angle. Background Art

[0002] The chassis of cargo handling equipment is very important, as it directly affects the stability, load-bearing capacity and movement performance of the handling equipment. The chassis usually includes key components such as the drive system, steering system, and braking system. The cooperation of each key component ensures that the cargo handling equipment can operate smoothly and safely.

[0003] Traditional cargo handling equipment is driven by internal combustion engines, which has problems with energy consumption, environmental pollution and noise. In recent years, some cargo handling equipment has changed its original drive mode to pure electric drive, but the chassis of the original cargo handling equipment has not been adapted. The traditional chassis is not flexible, which requires a very high level of control during turning and limits the ability of cargo handling equipment to operate in a small space.

[0004] The present application provides a steering control method based on a steering angle and a cargo handling device to solve the above-mentioned technical problems. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art; to this end, the present application proposes a steering control method and cargo handling equipment based on steering angle, which are used to solve the technical problems of insufficient chassis flexibility of cargo handling equipment, affecting its safety during turning and insufficient operation ability in a small space. The present application automatically matches the speed according to the steering curvature, combines differential steering technology to complete the turning, improves the chassis flexibility, and also improves the operation ability of the cargo handling equipment in a small space, solving the above-mentioned problems.

[0006] To achieve the above object, the first aspect of the present application provides a steering control method based on a steering angle, comprising:

[0007] The turning angle is collected in real time, and the speed parameter is calculated by combining the turning angle with basic parameters; wherein the speed parameter includes the target speed and acceleration, and the basic parameters include the basic acceleration, the turning angular velocity, the acceleration modulation ratio and the maximum set speed;

[0008] Steering control is performed based on the speed parameter.

[0009] Preferably, calculating the target speed according to the turning angle and the basic parameters includes:

[0010] The turning angle is normalized and marked as A;

[0011] The target speed V is calculated by the formula V=Vmax / 2×(A+1); wherein Vmax is the maximum set speed.

[0012] Preferably, calculating the acceleration according to the target speed includes:

[0013] The current driving speed is marked as V1; the acceleration a is determined by the following formula:

[0014]

[0015] Among them, Ja is the basic acceleration, We is the turning angular velocity, and K is the acceleration modulation ratio.

[0016] Preferably, the steering control based on the speed parameter includes:

[0017] The driving speed is collected according to the set sampling period; the sampling period can be 1s or 0.1s;

[0018] When the driving speed is less than or equal to the target speed, acceleration a is used for acceleration; otherwise, acceleration a is used for deceleration.

[0019] Preferably, the normalization process comprises:

[0020] The turning angle is normalized to [0, 1], wherein the value is 1 when driving in a straight line and the value is 0 when the maximum turning angle is reached.

[0021] Preferably, the acceleration modulation ratio is used to adjust the influence of the turning angular velocity on the acceleration.

[0022] A second aspect of the present application provides cargo handling equipment, which performs steering control based on a steering angle steering control method, including: a drive motor, a battery pack, a suspension module, a kinetic energy recovery module, a transmission module, a differential steering module and a control module;

[0023] Control module: It uses microprocessor technology to achieve precise control of each component of cargo handling equipment and has real-time monitoring function;

[0024] Differential steering module: Steering is achieved by distributing the wheel speeds on both sides through the differential;

[0025] Transmission module: drives the wheels through the differential and drive shaft.

[0026] Compared with the prior art, the beneficial effects of the present application are as follows: the present application collects the steering angle in real time, calculates the speed parameters, namely the target speed and acceleration, according to the steering angle and basic parameters; adjusts the driving speed by the acceleration so that the driving speed follows the target speed; moreover, the present application re-collects and calculates the data every other sampling period, and adjusts the acceleration and driving speed in time; the present application determines the calculation method of the acceleration by comparing the driving speed with the target speed, and then adjusts the driving speed according to the acceleration to ensure that the driving speed closely follows the target speed, which can ensure the safety and stability of the adjustment process, and can also avoid rollover during turning, thereby improving the overall safety of steering control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a flow chart of the steering control method of the present application;

[0029] Figure 2 This is a schematic diagram of the cargo handling equipment principle of this application. DETAILED DESCRIPTION

[0030] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0031] See also Figure 1 to Figure 2 The first embodiment of the present application provides a steering control method based on a steering angle, comprising:

[0032] Collect the turning angle in real time, and calculate the speed parameter by combining the turning angle with basic parameters; wherein the speed parameter includes the driving speed or the acceleration modulation ratio, and the basic parameters include the basic acceleration, the turning angular velocity, the acceleration modulation ratio and the maximum set speed;

[0033] Steering control is performed based on the speed parameter.

[0034] When cargo handling equipment is purely electric, the electric drive has lower latency and its performance is stronger. However, only the drive mode is adjusted, and the traditional chassis is not redesigned. Since the traditional chassis is not flexible, if it cannot be adjusted in time during the turn, it is easy to roll over due to excessive speed, which will cause great losses.

[0035] The present application calculates the driving speed and acceleration in real time by obtaining the steering angle without adjusting the chassis of the original cargo handling equipment, and realizes steering by distributing the wheel speeds on both sides through the differential. The steering control method can realize flexible steering through simple data processing, and can avoid the cargo handling equipment from losing control and causing losses during the turning process.

[0036] The turning angle of this embodiment can be obtained by various existing angle sensors, such as photoelectric angle sensors, Hall effect angle sensors, magnetoresistive effect angle sensors, etc. The steering angle is collected in real time during operation, and the driving speed and acceleration are adjusted according to the steering angle to avoid turning too fast and causing rollover. It should be noted that the steering angle in this embodiment is the steering angle of the wheels of the cargo handling equipment.

[0037] Before calculating the speed parameters, basic parameters need to be obtained, which specifically include the maximum set speed, turning angular velocity, acceleration modulation ratio and basic acceleration of the cargo transport equipment (or other equipment to which the steering control algorithm is applied).

[0038] After obtaining the steering angle, the steering angle needs to be normalized. Specifically, the steering angle is mapped to [0, 1] to facilitate the calculation of the driving speed. In the normalization process, the normalized result of the turning angle when driving in a straight line is 1, and the normalized result at the maximum turning angle is 0. The maximum turning angle here is set according to the device, and the maximum turning angle of different devices is different.

[0039] After normalization, the formula V=Vmax / 2×(A+1) can be used to calculate the driving speed, which is the safe driving speed in the current state. The cargo handling equipment will not roll over if it runs at this driving speed. After the driving speed is obtained, it is compared with the current driving speed of the cargo handling equipment to obtain the speed difference, which is the adjustment target.

[0040] Generally, the speed can be adjusted directly by means of sudden acceleration or sudden braking, and the driving speed can be quickly adjusted to the calculated driving speed, but this method is not safe enough. This embodiment adjusts the acceleration of the cargo transport equipment by adjusting the acceleration control ratio, thereby completing its speed adjustment. This method is safer and more reliable than the traditional speed adjustment method.

[0041] After the driving speed is obtained, it is compared with the target speed calculated above. When the driving speed is less than or equal to the target speed, acceleration is performed using the set basic acceleration, and calculations are performed again every sampling period to determine whether acceleration or deceleration is required. When the driving speed is greater than the target speed, acceleration is calculated based on the basic acceleration and the steering angular velocity, and deceleration is performed using this acceleration, and calculations are performed again every sampling period to determine whether acceleration or deceleration is required. The control reaction time in this embodiment is mainly a buffer time reserved to avoid sudden braking and acceleration. However, the adjustment time of the driving speed should also be considered during the setting, and the control reaction time should not be set too large.

[0042] It is worth noting that the safe speed of the cargo handling equipment is calculated by the steering angle (similar to the rotation angle of the steering wheel) during the turning process, that is, the target speed calculated by the formula. If a fixed acceleration is used to control the driving speed, there will be a risk of rollover if the deceleration is too slow during the deceleration process, and the driving experience will be affected if the deceleration is too fast. Therefore, the acceleration during the deceleration process changes dynamically according to the speed of the turning handle.

[0043] The above steering control method is described in detail with examples:

[0044] Assume that the turning angle collected in real time is the maximum turning angle, that is, A=0 after normalization, and the maximum set speed is 2m / s; substitute it into the formula V=Vmax / 2×(A+1) to get V=1m / s, that is, the driving speed of the cargo handling equipment should be below 1m / s at the current turning angle to avoid rollover;

[0045] The speed of the cargo handling equipment at this time is 2m / s, that is, the speed is greater than the target speed, and deceleration is required. The acceleration calculation formula a=Ja+We*K in this scenario can be used to calculate the acceleration a, and the cargo handling equipment is decelerated by the acceleration a.

[0046] Specifically, set the acceleration modulation ratio K = 1, and the basic acceleration Ja = 0.3;

[0047] Assuming that the angular velocity of the first steering is We = 0.2 rad / s, the acceleration a = 0.5 m / s2. It takes 2 seconds to reduce the driving speed from 2 m / s to 1.0 m / s with this acceleration a. That is, at least 2 seconds of deceleration with this acceleration can ensure the turning safety of the cargo handling equipment.

[0048] Assuming the angular velocity of the second steering is We = 0.7 rad / s, the acceleration a = 1.0 m / s2. It takes 1 second to reduce the driving speed from 2 m / s to 1.0 m / s with this acceleration a. That is, at least 1 second of deceleration with this acceleration can ensure the safety of the cargo handling equipment in turning. In this way, the deceleration time can be automatically adjusted by the speed of the steering handle to avoid rollover.

[0049] It should be explained that the acceleration modulation ratio of this embodiment is pre-set, and the factors affecting its size are mainly the type of cargo handling equipment, such as the structure or load-bearing capacity of the cargo handling equipment. In order to ensure that the left and right dimensions of the acceleration calculation formula are the same, the unit of the acceleration modulation ratio K is set to m / (rad*s), that is, the conversion of linear velocity and angular velocity.

[0050] In the process of adjusting the driving speed by acceleration, the calculation is re-collected every sampling period. Assuming the sampling period is 1s, the driving speed of the previous second is V1 (V1>V), then the driving speed of the next second is V2=V1-a×T, where T is the sampling period, so V2=V1-a×1. If V2 is still greater than V at this time, it is still adjusted by the calculated acceleration a.

[0051] In some other preferred embodiments, if directly adjusting the speed will not affect the safety of the cargo handling equipment, the travel speed can be adjusted directly without adjusting the acceleration modulation ratio.

[0052] A second aspect of the present application provides cargo handling equipment, which performs steering control based on a steering angle steering control method, including: a drive motor, a battery pack, a suspension module, a kinetic energy recovery module, a transmission module, a differential steering module and a control module;

[0053] Driving motor: adopts high-efficiency, low-noise design, has high torque output, and can adapt to various complex road conditions. The DC motor has good starting and speed regulation performance, a wide and smooth speed regulation range, strong overload capacity, and is less affected by electromagnetic interference; it has good starting and speed regulation characteristics; the torque is relatively large; the maintenance is relatively cheap; the DC motor's DC is more energy-saving and environmentally friendly than the AC; it is not sensitive to ambient temperature and can operate normally in a high temperature environment. Due to the front-wheel drive design, the chassis of the present invention can better provide power during driving and improve anti-skid performance.

[0054] Differential steering module: Steering is achieved by distributing the speed of the wheels on both sides through the differential, saving drive motors, simplifying control requirements, and significantly improving steering flexibility. The differential steering module has a high degree of accuracy and can achieve a very small turning radius. The system monitors the force of the left and right wheels and the chassis status in real time through the differential, accurately controls the speed of the wheels on both sides, and achieves smooth and flexible steering operations. When the chassis needs to turn, the differential system will adjust the speed of the drive motors on both sides according to the force. Compared with traditional chassis, this steering method has higher flexibility and accuracy.

[0055] Battery pack: High energy density materials are used to provide a longer driving range. The battery pack is designed with a complete management module to ensure good performance in various working environments. The management module includes a temperature sensor, a current sensor and a control unit, which can monitor the battery temperature and current in real time and provide protection to prevent overheating and short circuiting of the battery.

[0056] Suspension module: Adopt independent suspension design to improve comfort and handling stability. The suspension module has good shock absorption performance and can adapt to driving conditions on different roads. The independent suspension system supports each wheel through independent springs and shock absorbers, which can better absorb the impact caused by uneven roads and improve the driving stability of the chassis.

[0057] Kinetic energy recovery module: Uses brake energy recovery technology to improve energy utilization. During braking, kinetic energy is converted into electrical energy and stored in the battery pack to extend the driving range. The kinetic energy recovery module monitors the braking force and vehicle speed through sensors, adjusts the motor's power generation in real time, and converts braking energy into electrical energy for storage.

[0058] Transmission module: The present invention drives the wheels through a differential and a drive shaft to achieve a speed difference between the left and right wheels. Assuming that the vehicle turns right, the distance traveled by the right (inside) wheel must be smaller than that of the left (outside) wheel. If the speed output by the motor to the left and right wheels is the same, the distance traveled by the left and right wheels should also be the same, and the vehicle cannot turn at all. The role of the differential is to reduce the speed of the right (inside) wheel and increase the speed of the left (outside) wheel, thereby ensuring normal steering of the vehicle. The vehicle's passability is improved, the vehicle's ability to travel under complex road conditions is increased, the vehicle's service life is extended, and the wear of the tires and mechanical damage to the vehicle are reduced.

[0059] Control module: Using advanced microprocessor technology to achieve precise control of each component. The control module has a real-time monitoring function and can automatically adjust the drive motor speed and other parameters according to the driving environment and chassis status to ensure that the chassis can maintain optimal performance under various working conditions.

[0060] The above embodiments are only used to illustrate the technical method of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical method of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present application.

Claims

1. A steering control method based on a steering angle, characterized in that: include: The turning angle is collected in real time, and the speed parameter is calculated by combining the turning angle with basic parameters; wherein the speed parameter includes the target speed and acceleration, and the basic parameters include the basic acceleration, the turning angular velocity, the acceleration modulation ratio and the maximum set speed; Steering control is performed based on the speed parameter.

2. The steering control method based on steering angle according to claim 1, characterized in that: Calculating the target speed according to the turning angle and the basic parameters includes: The turning angle is normalized and marked as A; The target speed is calculated by the formula V=Vmax / 2×(A+1) and is marked as V; wherein Vmax is the maximum set speed.

3. The steering control method based on steering angle according to claim 2, characterized in that: The acceleration is calculated according to the target speed, including: The current driving speed is marked as V1; the acceleration a is determined by the following formula: Among them, Ja is the basic acceleration, We is the turning angular velocity, and K is the acceleration modulation ratio.

4. The steering control method based on steering angle according to claim 3, characterized in that: The steering control based on the speed parameter comprises: The driving speed is collected according to the set sampling period; the sampling period can be 1s or 0.1s; When the driving speed is less than or equal to the target speed, acceleration a is used for acceleration; otherwise, acceleration a is used for deceleration.

5. The steering control method based on steering angle according to claim 2, characterized in that: The standardization process includes: The turning angle is normalized to [0, 1], wherein the value is 1 when driving in a straight line and the value is 0 when the maximum turning angle is reached.

6. The steering control method based on steering angle according to claim 2, characterized in that: The acceleration modulation ratio is used to adjust the influence of the turning angular velocity on the acceleration.

7. Cargo handling equipment, wherein steering control is performed according to the steering control method based on steering angle according to any one of claims 1 to 6, characterized in that: Includes: drive motor, battery pack, suspension module, kinetic energy recovery module, transmission module, differential steering module and control module; Control module: It uses microprocessor technology to achieve precise control of each component of cargo handling equipment and has real-time monitoring function; Differential steering module: Steering is achieved by distributing the wheel speeds on both sides through the differential; Transmission module: drives the wheels through the differential and drive shaft.

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