Four-wheel differential control system of overhead working truck and control method of four-wheel differential control system

Abstract

The invention discloses a four-wheel differential control system of an overhead working truck and a control method of the four-wheel differential control system, and relates to the technical field of overhead working trucks, and the four-wheel differential control system comprises a vehicle control unit, a steering angle sensor, a remote controller and a wheel side motor which are in communication connection, and the steering angle sensor is used for detecting the steering angle of a vehicle; the remote controller is used for receiving an operation instruction and generating a control signal; the wheel-side motors respectively drive wheels of the overhead working truck; the vehicle control unit receives a control signal from the remote controller and a steering angle signal from the steering angle sensor, processes the control signal and the steering angle signal based on an integer operation mode, and calculates a target rotating speed of a wheel according to a differential relational expression; and each target rotating speed instruction is respectively sent to the corresponding wheel-side motor through the control signal output interface, so that the high-altitude operation process is safer and more reliable.

Description

Technical Field

[0001] This invention relates to the field of aerial work platform technology, and more specifically, to a four-wheel differential control system and control method for an aerial work platform. Background Technology

[0002] Traditional control methods for aerial work platforms mostly rely on mechanical differentials to achieve wheel differential speed. However, mechanical differentials have obvious limitations. On the one hand, the transmission response speed of mechanical structures is relatively slow, making it difficult to adapt to the frequent steering and speed adjustment requirements in aerial work scenarios. When the work platform operates in narrow areas or complex terrain, the lag of mechanical differentials can easily lead to wheel slippage and inaccurate steering, affecting work efficiency and safety. On the other hand, the structure of mechanical differentials is fixed, and it is impossible to flexibly adjust the speed distribution of each wheel according to different steering angles and driving speeds, resulting in poor adaptability and making it difficult to meet the diverse working conditions of aerial work platforms. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a four-wheel differential control system and control method for aerial work platforms.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A four-wheel differential control system for an aerial work platform includes a vehicle control unit, a steering angle sensor, a remote controller, and wheel-side motors connected by communication. The steering angle sensor is used to detect the vehicle's steering angle; The remote control is used to receive operation commands and generate control signals; The wheel-side motors drive the wheels of the aerial work platform vehicle. The vehicle control unit receives control signals from the remote controller and steering angle signals from the steering angle sensor. It processes the control signals and steering angle signals using an integer arithmetic method, calculates the target rotational speed of the wheels according to the differential speed formula, and sends each target rotational speed command to the corresponding wheel-side motor through the control signal output interface.

[0005] Preferably, the differential speed formula is used to calculate the left front wheel speed V1, right front wheel speed V2, left rear wheel speed V3 and right rear wheel speed V4 based on the target speed V of the rear axle center, steering angle δ, wheelbase L, track width C and the distance B between the rear axle and the center of gravity.

[0006] Preferably, the differential speed relationship is as follows: ; ; ; .

[0007] Preferably, the vehicle control unit is connected to each wheel-side motor via a CAN bus.

[0008] Preferably, it also includes a hydraulic steering mechanism, wherein the vehicle control unit controls the hydraulic steering mechanism to achieve coordination between steering control and drive differential by driving a solenoid valve.

[0009] Preferably, the steering angle sensor detects a steering angle range of -40 degrees to 40 degrees.

[0010] A four-wheel differential speed control method for an aerial work platform vehicle, the method comprising the following steps: Communication between the vehicle control unit and the steering angle sensor, remote control, and wheel-side motors; Receive control signals from the remote controller and analyze them to obtain the target rotational speed V and steering direction of the rear axle center; Receive the steering angle signal δ from the steering angle sensor; The vehicle control unit calculates the target speeds of the left front wheel, right front wheel, left rear wheel, and right rear wheel based on the four-wheel differential relationship, the target speed V of the rear axle center, the steering angle δ, the wheelbase L, the track width C, and the distance B between the rear axle and the center of gravity. The vehicle control unit sends the calculated target speed commands to the corresponding wheel-side motors; Each wheel-side motor drives the corresponding wheel to rotate according to the received target speed command, so as to realize four-wheel differential control.

[0011] Compared with the prior art, the present invention has the following beneficial effects: This invention continuously monitors the vehicle's steering angle, capturing subtle changes in steering action in real time and promptly acquiring steering status. The remote control directly receives operation commands and generates control signals. Each wheel-side motor independently drives each wheel, meaning each wheel can adjust its speed as needed, no longer limited by traditional mechanical differential structures. Operators adjust steering via the remote control; the steering angle sensor captures small-angle steering signals, and the vehicle control unit can specifically adjust the speed of each wheel-side motor, allowing the wheels to maintain a differential state suitable for small steering angles. This makes vehicle steering more flexible and precise, reducing operational difficulties caused by limited working space. It also improves vehicle stability and operational safety. Based on the differential relationship, combined with steering angle, vehicle structural parameters, and other data, the vehicle control unit calculates the target wheel speed, ensuring that the speed of each wheel matches driving or steering needs, preventing wheel slippage. This avoids the risk of vehicle rollover due to slippage, making high-altitude operations safer and more reliable. Attached Figure Description

[0012] Figure 1This invention provides a schematic diagram of the steps of a four-wheel differential control method for an aerial work platform vehicle. Figure 2 This is a schematic diagram of steering proposed in an embodiment of the present invention. Detailed Implementation

[0013] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0015] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0016] Reference Figures 1-2 As shown.

[0017] The embodiments further illustrate the four-wheel differential speed control system and control method of the aerial work vehicle proposed in this invention.

[0018] A four-wheel differential control system for an aerial work platform includes a vehicle control unit, a steering angle sensor, a remote controller, and wheel-side motors connected by communication. Steering angle sensors are used to detect the vehicle's steering angle; The remote control is used to receive operating commands and generate control signals; The wheel-side motors drive the wheels of the aerial work platform vehicle. The vehicle control unit receives control signals from the remote controller and steering angle signals from the steering angle sensor. It processes the control signals and steering angle signals using an integer arithmetic method, calculates the target wheel speeds based on the differential speed formula, and sends each target speed command to the corresponding wheel-side motor through the control signal output interface.

[0019] The steering angle sensor is a component that acquires steering information. Its function is to continuously detect the vehicle's current steering angle. For example, when the operator turns the steering wheel to the left, the steering angle sensor captures the angle value corresponding to this steering action in real time. These values ​​will be transmitted as key signals to the subsequent control unit to provide basic steering data support for differential adjustment of the wheels.

[0020] The remote control receives operation commands and converts them into control signals. When the operator needs to adjust the vehicle's speed or steering direction during operation, they issue commands by operating the corresponding buttons or levers on the remote control. After receiving these operation commands, the remote control converts them into control signals that the system can recognize. For example, if the operator pushes the speed adjustment lever on the remote control to increase the vehicle's speed, the remote control generates a corresponding speed control signal and then transmits these signals to the vehicle control unit.

[0021] Wheel-side motors are actuators that directly drive the rotation of the wheels. Each wheel is equipped with an independent wheel-side motor, which means that each wheel can achieve individual speed adjustment under the drive of the motor. For example, when the vehicle needs to perform a steering operation, the wheel-side motors of different wheels can run at different speeds, thereby making the wheels present different rotation speeds, providing a hardware basis for differential control.

[0022] The vehicle control unit receives control signals from the remote controller and steering angle signals from the steering angle sensor. Upon receiving these signals, the control unit processes them using integer arithmetic, a method that enables efficient and accurate signal processing. Based on a preset differential speed formula and the received signal data, the control unit calculates the target speed for each wheel. For example, it combines the speed control signal from the remote controller, the steering angle from the steering angle sensor, and parameters such as the vehicle's wheelbase and track width to calculate the required speeds for the left front wheel, right front wheel, left rear wheel, and right rear wheel. After calculation, the vehicle control unit sends these different target speed commands to the corresponding wheel-side motors via the control signal output interface. Each wheel-side motor adjusts its operating speed accordingly upon receiving the command, thereby driving the corresponding wheel to rotate at the target speed. This ultimately achieves four-wheel differential control for the aerial work platform, making the vehicle more stable and precise during driving and turning.

[0023] The differential speed formula is used to calculate the left front wheel speed V1, right front wheel speed V2, left rear wheel speed V3, and right rear wheel speed V4 based on the target speed V of the rear axle center, steering angle δ, wheelbase L, track width C, and distance B between the rear axle and the center of gravity.

[0024] The differential speed relationship is as follows: ; ; ; .

[0025] Achieving precise matching of four-wheel speeds makes vehicle driving more stable. The differential speed formula calculates the speed of each wheel based on core parameters such as the target speed of the rear axle center, steering angle, and the vehicle's wheelbase, track width, and distance between the rear axle and the center of gravity. These parameters encompass key information about the vehicle's structure and driving status, ensuring that the target speed of each wheel matches actual driving needs. For example, when an aerial work platform needs to turn at a certain target speed of the rear axle center, the steering angle will change. At this time, the differential speed formula, combined with fixed parameters such as wheelbase and track width, can calculate the speeds of the left front wheel, right front wheel, left rear wheel, and right rear wheel separately. For instance, the speed of the left front wheel is calculated by integrating the geometric relationship corresponding to the steering angle with vehicle structural parameters, while the speed of the right front wheel takes into account the difference in turning radius caused by the track width. In this way, the speeds of different wheels are adapted to the trajectory requirements during steering, avoiding unnecessary friction between the wheels and the ground, and making the vehicle more stable during steering.

[0026] This allows for a more accurate adaptation of the four-wheel differential control to the vehicle's actual structure, enhancing its control effectiveness. The differential formula incorporates the distance between the rear axle and the center of gravity. The center of gravity is where the vehicle's weight is concentrated; this parameter ensures that the calculated rotational speed more closely reflects the vehicle's weight distribution. For example, even though the distance between the center of gravity and the rear axle remains constant under different load conditions, calculating the wheel speeds using this parameter allows for a more rational distribution of driving force to each wheel. This prevents any wheel from experiencing excessive wear due to uneven force distribution. Furthermore, it ensures that the vehicle's stability in driving and steering is unaffected by the load when carrying work equipment, guaranteeing safety during operations.

[0027] This facilitates efficient signal processing by the vehicle control unit. The derivation of the differential relationship formula is based on the correlation between geometric trajectory and vehicle structure. Whether it's the calculation of the rotational speed of the left and right front wheels or the left and right rear wheels, it relies on the same basic parameter system, only adjusting the combination of parameters according to the differences in wheel position. For example, the calculation of the rotational speed of the left and right rear wheels is derived by combining the geometric relationship of parameters such as steering angle, wheelbase, and track width. In this way, when the vehicle control unit processes signals using integer arithmetic, it can quickly complete the calculation of the rotational speed of each wheel based on a unified logical framework, reducing computational complexity, improving the timeliness of command issuance, allowing the wheels to respond quickly to control signals, and ensuring the smoothness of the aerial work platform vehicle's driving and steering during operation.

[0028] The vehicle control unit communicates with each wheel-side motor via a CAN bus.

[0029] It also includes a hydraulic steering mechanism, in which the vehicle control unit controls the hydraulic steering mechanism by driving solenoid valves to achieve coordination between steering control and drive differential.

[0030] First, let's discuss the communication connection between the vehicle control unit and the wheel-side motors. The CAN bus is used for communication. The CAN bus offers stable and efficient signal transmission, allowing simultaneous connection of multiple devices and rapid data exchange. Once the vehicle control unit calculates the target speed for each wheel, it synchronously sends the corresponding speed command to each wheel-side motor via the CAN bus. Each wheel-side motor can independently receive and recognize its own command. For example, when the vehicle needs to turn, the control unit calculates different target speeds for the left front wheel, right front wheel, etc. These speed commands are transmitted to the corresponding wheel-side motors via the CAN bus. Each wheel-side motor adjusts its own speed according to the command, thereby driving the wheels to achieve differential rotation and ensuring vehicle stability during steering.

[0031] Secondly, there's the coordinated control logic of the hydraulic steering mechanism. The system is equipped with a hydraulic steering mechanism, and the vehicle control unit controls its movement by driving solenoid valves. When the operator issues a steering command, the vehicle control unit not only calculates the differential speed of each wheel but also simultaneously sends a control signal to the solenoid valve. Upon receiving the signal, the solenoid valve adjusts the pressure and flow of the hydraulic system, thereby controlling the hydraulic steering mechanism to complete the steering action. Simultaneously, the steering angle sensor feeds back the actual steering angle to the control unit. The control unit combines this angle data to optimize the differential speed commands for the wheels, ensuring that the steering action and the differential drive of the wheels are coordinated. For example, when the vehicle's steering angle increases, the control unit adjusts the amplitude of the hydraulic steering mechanism's movement through the solenoid valve, while simultaneously adjusting the speed difference between the motors at each wheel, matching the change in steering angle with the change in wheel speed. This avoids asynchrony between steering and drive, ultimately achieving coordinated operation of steering control and differential drive, improving the vehicle's handling stability during driving and operation.

[0032] The steering angle sensor detects steering angles ranging from -40 degrees to 40 degrees.

[0033] The steering angle sensor is a key component in the four-wheel differential control system of aerial work platforms, acquiring steering information. Its core operating characteristic is that its detection range is set from -40 degrees to 40 degrees. The angle range corresponds to the actual steering operation range of the vehicle, where a negative angle usually represents one steering direction, and a positive angle represents the opposite steering direction. For example, when the operator turns the steering wheel to the right, the steering angle sensor will detect a negative angle value, while turning to the left will detect a positive angle value.

[0034] During actual operation, when the vehicle needs to turn, the operator's steering action drives the steering mechanism. The steering angle sensor captures the angle value corresponding to this action in real time, and this angle value is always within the range of -40 degrees to 40 degrees. For example, if the operator slightly turns the steering wheel to turn the vehicle at a small angle, the angle detected by the sensor is -10 degrees or 8 degrees; if the operator makes a larger steering operation, the angle detected by the sensor is close to -40 degrees or 40 degrees, but will not exceed this range. This setting not only adapts to the common steering needs of aerial work platforms in operating scenarios, but also avoids the operational risks caused by oversteering.

[0035] The signal from the detection range is transmitted to the vehicle control unit. The control unit combines this angle data with the differential speed formula to calculate the target speed of each wheel. For example, when the sensor detects a steering angle of 30 degrees, the control unit uses this angle value to match parameters such as wheelbase and track width to calculate the corresponding speeds of the left front wheel, right front wheel, etc., thereby achieving precise differential speed control. This ensures that the vehicle's steering action matches the wheel speed adjustment, guaranteeing stability during driving and operation.

[0036] A four-wheel differential speed control method for an aerial work platform vehicle, the method comprising the following steps: Communication between the vehicle control unit and the steering angle sensor, remote control, and wheel-side motors; Receive control signals from the remote controller and analyze them to obtain the target rotational speed V and steering direction of the rear axle center; Receive the steering angle signal δ from the steering angle sensor; The vehicle control unit calculates the target speeds of the left front wheel, right front wheel, left rear wheel, and right rear wheel based on the four-wheel differential relationship, the target speed V of the rear axle center, the steering angle δ, the wheelbase L, the track width C, and the distance B between the rear axle and the center of gravity. The vehicle control unit sends the calculated target speed commands to the corresponding wheel-side motors; Each wheel-side motor drives the corresponding wheel to rotate according to the received target speed command, so as to realize four-wheel differential control.

[0037] First, communication connections between the vehicle control unit and each component need to be established. The vehicle control unit must establish a stable communication link with the steering angle sensor remote controller and the wheel-side motors to ensure smooth signal transmission between the components. For example, during the device startup phase, communication pairing between these components and the control unit can be automatically completed, allowing the control unit to receive signals from the sensors and remote controller, and also send commands to the wheel-side motors.

[0038] The system receives and analyzes control signals from the remote control. When an operator operates the vehicle via the remote control, the remote control generates a corresponding control signal and transmits it to the vehicle control unit. The control unit receives and analyzes the signal, extracting the target speed at the rear axle center and the steering direction. For example, if the operator pushes the speed adjustment lever on the remote control, the control unit can analyze the target speed the rear axle center needs to achieve; similarly, if the operator moves the steering lever, the control unit can analyze the corresponding steering direction.

[0039] The control unit receives steering angle signals from the steering angle sensor. The steering angle sensor detects the vehicle's steering angle in real time and continuously transmits this angle signal to the control unit. The control unit synchronously acquires this signal to provide data support for subsequent speed calculations. For example, if the sensor detects a steering angle of 20 degrees when the vehicle is actually turning, this 20-degree signal is received and recorded by the control unit.

[0040] The vehicle control unit calculates the target speed of each wheel using integer arithmetic. The control unit calls upon a preset four-wheel differential relationship, combining the analytically obtained target speed and steering angle at the rear axle center, as well as fixed parameters such as the vehicle's wheelbase, track width, and distance between the rear axle and center of gravity, to perform the calculation using integer arithmetic. This calculation method can efficiently and accurately determine the target speeds for the left front wheel, right front wheel, left rear wheel, and right rear wheel. For example, combining a target rear axle center speed of 1000 rpm and a steering angle of 20 degrees, along with parameters such as wheelbase and track width, the control unit calculates that the required speed for the left front wheel is 1050 rpm, and for the right front wheel, it is 1200 rpm.

[0041] The vehicle control unit sends target speed commands to the corresponding wheel-side motors. The control unit transmits the speed commands for each wheel to the corresponding wheel-side motors via a communication link, ensuring that each wheel-side motor receives its own speed command.

[0042] Each wheel-side motor drives the corresponding wheel to rotate according to the received target speed command. Each wheel-side motor adjusts its own operating speed according to the command, thereby driving the corresponding wheel to rotate at the target speed. The difference in speed between different wheels realizes four-wheel differential control. For example, after receiving a command of 1050 revolutions per minute, the wheel-side motor of the left front wheel drives the left front wheel to rotate at that speed, while the wheel-side motor of the right front wheel drives the right front wheel to rotate at 1200 revolutions per minute, ultimately keeping the vehicle stable when driving or turning.

[0043] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0044] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A four-wheel differential control system of an aerial work platform, characterized in that, The vehicle control unit, the steering angle sensor, the remote controller and the wheel motor are connected by communication connection: The steering angle sensor is used to detect the steering angle of the vehicle; The remote controller is used to receive operation instructions and generate control signals; The wheel motor drives the wheels of the aerial work platform respectively; The vehicle control unit receives the control signals from the remote controller and the steering angle signals from the steering angle sensor, processes the control signals and the steering angle signals based on the integer operation mode, calculates the target rotating speed of the wheels according to the differential relationship, and sends each target rotating speed instruction to the corresponding wheel motor through the control signal output interface.

2. The four-wheel differential control system of the aerial work platform according to claim 1, characterized in that, The differential relationship is used to calculate the left front wheel rotating speed V1, the right front wheel rotating speed V2, the left rear wheel rotating speed V3 and the right rear wheel rotating speed V4 according to the rear axle center target rotating speed V, the steering angle δ, the wheelbase L, the track C and the distance B between the rear axle and the center of mass.

3. The four-wheel differential control system of the aerial work platform according to claim 2, characterized in that, The differential relationship is specifically: ; ; ; 。 4. The four-wheel differential control system of the aerial work platform according to claim 1, characterized in that, The vehicle control unit is connected with each wheel motor by CAN bus.

5. The four-wheel differential control system of the aerial work platform according to claim 1, characterized in that, It also includes a hydraulic steering mechanism, and the vehicle control unit controls the action of the hydraulic steering mechanism by driving the electromagnetic valve to realize the coordination of steering control and drive differential.

6. The four-wheel differential control system of the aerial work platform according to claim 1, characterized in that, The steering angle detected by the steering angle sensor ranges from -40 degrees to 40 degrees.

7. A four-wheel differential control method of a high-altitude operation vehicle, applied to the four-wheel differential control system of any one of claims 1 to 6, characterized in that, The method comprises the following steps: The communication between the vehicle control unit, the steering angle sensor, the remote controller and the wheel motor; Receiving the control signal from the remote controller and analyzing to obtain the rear axle center target rotating speed V and the steering direction; Receiving the steering angle signal δ from the steering angle sensor; The vehicle control unit calculates the target rotating speed of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel based on the integer operation according to the four-wheel differential relationship, the rear axle center target rotating speed V, the steering angle δ, the wheelbase L, the track C and the distance B between the rear axle and the center of mass; The vehicle control unit sends each target rotating speed instruction calculated to the corresponding wheel motor; Each wheel motor drives the corresponding wheel to rotate according to the received target rotating speed instruction to realize four-wheel differential control.

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