Mecanum wheel and air cushion combined transport vehicle and motion control method

Abstract

According to the Mecanum wheel and air cushion combined transport vehicle and the motion control method, the air cushion is used as a main load bearing mode, the Mecanum wheels are used as a main driving mode, omni-directional movement under the large-load condition is achieved, high-precision butt joint of sections is achieved, and the transport vehicle is convenient to use. The advantage of large bearing capacity of the air cushion transport vehicle and the advantages of omni-directional movement and high-precision positioning of the Mecanum wheels are brought into full play, the flexibility of the air cushion transport vehicle is improved, and the application scene of the air cushion transport vehicle is widened.

Description

A transport vehicle combining Mecanum wheels and air cushions and its motion control method Technical Field

[0001] This invention relates to the field of automatic control technology, and in particular to a transport vehicle combining Mecanum wheels and air cushions, and a motion control method thereof. Background Technology

[0002] Air cushion transport vehicles have a wide range of applications in many heavy-duty fields due to their large load capacity. However, in fields such as wind tunnels, large wind tunnel sections not only require high loads but also high motion precision. Traditional pneumatic wheel sets cannot meet the requirements for real-time omnidirectional movement and high-precision motion range. Summary of the Invention

[0003] The present invention aims to provide a transport vehicle and motion control method that overcomes or at least partially solves the above-mentioned problems by combining Mecanum wheels and air cushions.

[0004] To achieve the above objectives, the technical solution of the present invention is specifically implemented as follows:

[0005] One aspect of the present invention provides a transport vehicle combining Mecanum wheels and air cushions, comprising: a vehicle body and an air cushion module disposed at the bottom of the vehicle body, and further comprising: a Mecanum wheel assembly and an elastic hydraulic module;

[0006] The Mecanum wheelset is connected to the vehicle body via the elastic hydraulic module;

[0007] The elastic hydraulic module is configured to drive the Mecanum wheel assembly to descend and contact the ground after the air cushion module is activated to form air buoyancy, and maintain the pressure between the Mecanum wheel assembly and the ground within a preset range.

[0008] Optionally, the flexible hydraulic module includes: a hydraulic cylinder, a hydraulic pump station, and a relief valve;

[0009] The hydraulic cylinder is a bidirectional push cylinder, with its cylinder body hinged to the vehicle body and its piston rod end hinged to the Mecanum wheel set;

[0010] The overflow valve is located on the hydraulic cylinder that controls the lifting of the entire vehicle.

[0011] Optionally, the elastic hydraulic module further includes a pressure sensor, which is mounted on the hydraulic cylinder on the side controlling the lifting of the vehicle, and is used to detect the oil pressure of the hydraulic cylinder.

[0012] Optionally, the flexible hydraulic module further includes: a directional valve, a check valve, and a solenoid valve;

[0013] The reversing valve is located between the oil inlet and the oil outlet;

[0014] The solenoid valve is located between the oil inlet of the directional valve and the hydraulic cylinder;

[0015] The one-way valve is located between the oil outlet of the reversing valve and the hydraulic cylinder.

[0016] Optionally, the set pressure value P of the relief valve satisfies the following relationship:

[0017] 1.2F n / πr 2 ≤P≤F max / πr 2

[0018] Wherein, Fn is the target positive pressure that the Mecanum wheel assembly needs to maintain with the ground, Fmax is the maximum positive pressure that the Mecanum wheel assembly can withstand, and r is the radius of the hydraulic cylinder.

[0019] Optionally, the Mecanum wheel assembly includes a Mecanum wheel, a servo motor driving the Mecanum wheel, and a speed reducer disposed between the servo motor and the Mecanum wheel.

[0020] Another aspect of the present invention provides a motion control method for a transport vehicle as described above, comprising:

[0021] S1: Activate the air cushion module to lift the vehicle body using air buoyancy;

[0022] S2: When the vehicle body is detected to be lifted off the ground, the elastic hydraulic module is controlled to move, driving the Mecanum wheel set to descend until it contacts and compacts the ground.

[0023] S3: Control the movement of the Mecanum wheel set to achieve omnidirectional movement of the transport vehicle;

[0024] During movement, the pressure between the Mecanum wheel assembly and the ground is maintained within a preset range through the dynamic adjustment of the elastic hydraulic module.

[0025] Optionally, in step S2, the lifting status of the vehicle body off the ground is detected by a height sensor.

[0026] Optionally, during the movement in step S3, when load fluctuations cause the ground pressure of the Mecanum wheel set to increase, the overflow valve in the elastic hydraulic module opens to overflow, so as to prevent the pressure from exceeding the preset maximum value; when load fluctuations cause the ground pressure to decrease, the hydraulic pump station of the elastic hydraulic module replenishes oil to the hydraulic cylinder to maintain the positive pressure.

[0027] Optionally, before step S1, the overflow pressure of the elastic hydraulic module is adjusted.

[0028] Therefore, the transport vehicle and motion control method combining Mecanum wheels and air cushions provided by this invention, with air cushions as the main load-bearing structure and Mecanum wheels as the main driving mechanism, achieves omnidirectional movement under heavy load conditions and high-precision docking of sections. It fully leverages the advantages of the air cushion transport vehicle in terms of heavy load-bearing capacity and the advantages of the Mecanum wheels in terms of omnidirectional movement and high-precision positioning, thereby improving the flexibility and application scenarios of the air cushion transport vehicle. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is a schematic diagram of the structure of the transport vehicle combining Mecanum wheels and air cushions provided in an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the passive lifting hydraulic suspension principle provided in an embodiment of the present invention;

[0032] Figure 3 is a flowchart of the motion control method provided in an embodiment of the present invention;

[0033] Figure 4 is a flowchart of a specific example of the motion control method provided in the embodiment of the present invention. Detailed Implementation

[0034] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0035] Figure 1 shows a schematic diagram of the structure of the transport vehicle with Mecanum wheel and air cushion combination provided in the embodiment of the present invention. Referring to Figure 1, the transport vehicle with Mecanum wheel and air cushion combination provided in the embodiment of the present invention includes: a vehicle body and an air cushion module disposed at the bottom of the vehicle body, and also includes: a Mecanum wheel set and an elastic hydraulic module.

[0036] The Mecanum wheelset is connected to the vehicle body via the elastic hydraulic module;

[0037] The elastic hydraulic module is configured to drive the Mecanum wheel assembly to descend and contact the ground after the air cushion module is activated to form air buoyancy, and maintain the pressure between the Mecanum wheel assembly and the ground within a preset range.

[0038] Specifically, the transport vehicle combining Mecanum wheels and air cushions provided by the present invention uses air cushions as the main load-bearing structure and Mecanum wheels as the main driving mechanism to achieve omnidirectional movement under heavy load conditions and to achieve high-precision docking of sections.

[0039] The Mecanum wheelset of this invention is connected to the air cushion transport vehicle through an elastic hydraulic module. The elastic hydraulic module enables the passive elastic lifting and lowering of the Mecanum wheelset. During the air buoyancy movement, the Mecanum wheelset maintains a constant pressure with the ground, thereby protecting the wheelset while ensuring sufficient friction between the wheelset and the ground, thus achieving precise movement.

[0040] This invention combines Mecanum wheels with air cushions to design a brand-new air cushion transport vehicle. At the same time, the passive hydraulic springs ensure the driving force of the Mecanum wheel set, making it convenient and quick to combine heavy loads and high-precision motion.

[0041] Specifically, the transport vehicle of the present invention mainly comprises three parts: an air cushion module, a Mecanum wheel set, and an elastic hydraulic module.

[0042] The air cushion module mainly consists of a pneumatic control valve group, an air inlet pipe, and an air cushion, which can control the air buoyancy force and complete the lifting of heavy-duty products.

[0043] The flexible hydraulic module mainly realizes the lifting and lowering of the Mecanum wheel set, and can achieve the passive lifting and lowering function according to the load through hydraulic control.

[0044] As an optional embodiment of the present invention, the Mecanum wheel set includes a Mecanum wheel, a servo motor driving the Mecanum wheel, and a reducer disposed between the servo motor and the Mecanum wheel. Specifically, the Mecanum wheel set comprises a Mecanum wheel, a high-precision servo motor, and a precision reducer, enabling omnidirectional movement and precise motion control of the air cushion transport vehicle.

[0045] As an optional embodiment of the present invention, the flexible hydraulic module includes: a hydraulic cylinder, a hydraulic pump station, and an overflow valve; the hydraulic cylinder is a bidirectional push cylinder, its cylinder body is hinged to the vehicle body, and its piston rod end is hinged to the Mecanum wheel set; the overflow valve is disposed on the hydraulic cylinder controlling the lifting of the entire vehicle. The flexible hydraulic module also includes a pressure sensor, which is disposed on the hydraulic cylinder controlling the lifting of the entire vehicle and is used to detect the oil pressure of the hydraulic cylinder.

[0046] Specifically, the hydraulic cylinder corresponding to each Mecanum wheelset is designed as a bidirectional push cylinder, which can meet the independent lifting function of each Mecanum wheelset. At the same time, each Mecanum wheelset is equipped with an overflow valve and a pressure sensor at the cylinder on the side that controls the lifting of the whole vehicle.

[0047] During the air-cushion transport vehicle's air-bearing movement, the air cushion may experience slight swaying due to varying ground conditions and load. Without an overflow valve, under heavy loads, the wheelset could deform or be completely damaged due to excessive pressure. By adding an overflow valve, when the load sways and the pressure on a particular wheelset becomes too high, the hydraulic cylinder pressure increases instantaneously, and the oil in the cylinder is discharged through the overflow valve, thus protecting the wheelset from damage due to excessive pressure.

[0048] As an optional embodiment of the present invention, the elastic hydraulic module further includes: a reversing valve, a check valve, and a solenoid valve;

[0049] The reversing valve is located between the oil inlet and the oil outlet;

[0050] The solenoid valve is located between the oil inlet of the directional valve and the hydraulic cylinder;

[0051] The one-way valve is located between the oil outlet of the reversing valve and the hydraulic cylinder.

[0052] Specifically, the solenoid valve can control the oil intake of the hydraulic cylinder, the check valve prevents oil from entering the hydraulic cylinder outlet line, and the directional valve can switch the oil inlet and outlet.

[0053] As an optional embodiment of the present invention, the set pressure value P of the relief valve satisfies the following relationship:

[0054] 1.2F n / πr 2 ≤P≤F max / πr 2

[0055] Wherein, Fn is the target positive pressure that the Mecanum wheel assembly needs to maintain with the ground, Fmax is the maximum positive pressure that the Mecanum wheel assembly can withstand, and r is the radius of the hydraulic cylinder.

[0056] Specifically, assuming the required normal force between the wheel assembly and the ground during air buoyancy is Fn, and the maximum normal force the wheel assembly can withstand is Fmax, under normal design, Fmax > 2Fn. Therefore, the value of the hydraulic cylinder overflow valve of the hydraulic suspension should be adjusted as follows:

[0057] 1.2F n / πr 2 ≤P≤F max / πr 2

[0058] Where r is the radius of the hydraulic suspension cylinder.

[0059] Specifically, when the load swings in the opposite direction, the hydraulic cylinder pressure decreases, and the transport wheel assembly separates from the ground. Therefore, in order to ensure that the wheel assembly is in contact with the ground, the pump station needs to be turned on and oil needs to be continuously supplied to the pump station.

[0060] Before controlling the movement of the transport vehicle, the present invention can set the overflow pressure of the overflow valve to ensure that the pressure between the Mecanum wheel set and the ground is maintained within a preset range when the Mecanum wheel set descends and contacts the ground.

[0061] Specifically, the control of transport vehicles can be achieved in the following way:

[0062] Before system operation, adjust the overflow pressure of the hydraulic module. The hydraulic module will not start if the transport vehicle is not in air-float mode. When air-float is activated, the height sensor detects that the load has lifted off the ground. At this time, the oil pump and inlet valve group open, the Mecanum wheels descend and compact with the ground, and oil continues to be added to the cylinders. Simultaneously, the air float rises continuously. During this time, the Mecanum wheels remain in contact with the ground. When the oil pressure in the cylinder reaches the pressure of the overflow valve, the Mecanum wheel pressure stops increasing, and the oil returns to the cylinder through the overflow valve. Activate the Mecanum wheel travel control. During travel, if the load decreases, excess oil in the cylinder and oil supplied by the pump station return to the cylinder through the overflow valve, maintaining a constant Mecanum wheel pressure. If the air float rises, the overflow valve stops overflowing, and the pump station supplies oil to the cylinder, continuing to maintain a constant cylinder pressure. This ensures that the Mecanum wheels maintain the same pressure with the ground throughout the entire process.

[0063] Therefore, the Mecanum wheel and air cushion combination transport vehicle provided in this embodiment of the invention combines Mecanum wheels with an air cushion transport vehicle, possessing both high load-bearing capacity and omnidirectional high-precision movement capabilities. Automatic lifting and constant pressure control of the wheel assembly according to the load is achieved through hydraulic cylinders and overflow valves. During air-bearing movement, the contact pressure between the wheel assembly and the ground is adjusted in real time through the hydraulic system to ensure driving force and wheel assembly protection. Based on height sensors and hydraulic feedback, the entire process of air-bearing start-up, wheel assembly compaction, and travel control is automated. Therefore, this invention enables omnidirectional movement and high-precision positioning under heavy load conditions; improves the adaptability and stability of the transport vehicle under complex ground conditions; effectively protects the wheel assembly and extends equipment lifespan; and expands the application of air cushion transport vehicles in high-requirement scenarios such as wind tunnels and heavy equipment docking.

[0064] Figure 3 shows a flowchart of the motion control method for a transport vehicle provided in an embodiment of the present invention. This motion control method is applied to the aforementioned transport vehicle. The following is only a brief description of the motion control method for the transport vehicle. For other matters not covered herein, please refer to the relevant descriptions in the above-mentioned transport section. Referring to Figure 3, the motion control method for the aforementioned transport vehicle provided in an embodiment of the present invention includes:

[0065] S1: Activate the air cushion module to lift the vehicle body using air buoyancy;

[0066] S2: When the vehicle body is detected to be lifted off the ground, the elastic hydraulic module is controlled to move, driving the Mecanum wheel set to descend until it contacts and compacts the ground.

[0067] S3: Control the movement of the Mecanum wheel set to achieve omnidirectional movement of the transport vehicle;

[0068] During movement, the pressure between the Mecanum wheel assembly and the ground is maintained within a preset range through the dynamic adjustment of the elastic hydraulic module.

[0069] As an optional implementation of this invention, in step S2, the lifting status of the vehicle body off the ground is detected by a height sensor.

[0070] As an optional embodiment of the present invention, during the movement in step S3, when load fluctuations cause the ground pressure of the Mecanum wheel set to increase, the overflow valve in the elastic hydraulic module opens to overflow, so as to prevent the pressure from exceeding the preset maximum value; when load fluctuations cause the ground pressure to decrease, the hydraulic pump station of the elastic hydraulic module replenishes oil to the hydraulic cylinder to maintain the positive pressure.

[0071] As an optional embodiment of the present invention, before step S1, the overflow pressure of the elastic hydraulic module is adjusted.

[0072] The following description uses Figure 4 as an example to illustrate the motion control of the transport vehicle, but the present invention is not limited thereto. Referring to Figure 4, the motion control method for the transport vehicle of the present invention includes:

[0073] Adjust the overflow pressure of the overflow valve in the elastic hydraulic module;

[0074] Determining if air flotation is enabled: If the transport vehicle is not in air flotation mode, the hydraulic module will not start. When air flotation is enabled, the height sensor detects that the load is off the ground, thus determining if air flotation is enabled.

[0075] If air flotation is detected, determine if the load is off the ground; if air flotation is not detected, shut down the pump station.

[0076] If the load is off the ground, the oil pump and inlet valve group will open, the Mecanum wheel will descend and compact with the ground, and continue to add oil to the cylinder. At the same time, the air float will rise continuously. At this time, the Mecanum wheel group will always be in contact with the ground. When the oil pressure in the cylinder reaches the pressure of the relief valve, the pressure of the Mecanum wheel group will no longer increase, and the oil will return to the cylinder from the relief valve.

[0077] Determine if the cylinder pressure exceeds the threshold.

[0078] If the threshold is not exceeded, the Mecanum wheel travel control is activated. During travel, if the load decreases, excess oil in the cylinder and oil supplied by the pump station to the cylinder return to the cylinder through the overflow valve, and the Mecanum wheel set pressure remains constant. If the air float rises, the overflow valve stops overflowing, and the pump station supplies oil to the cylinder, continuing to maintain a constant cylinder pressure. This ensures that the Mecanum wheel set maintains the same pressure as the ground throughout the entire process.

[0079] If the threshold is exceeded, movement stops and pressure is actively released.

[0080] Therefore, the motion control method of the Mecanum wheel and air cushion combination transport vehicle provided in this embodiment of the invention combines the Mecanum wheel and air cushion transport vehicle, possessing both high load-bearing capacity and omnidirectional high-precision motion capability; the automatic lifting and lowering of the wheel assembly according to the load and constant pressure control are achieved through hydraulic cylinders and overflow valves; during air buoyancy movement, the contact pressure between the wheel assembly and the ground is adjusted in real time through the hydraulic system to ensure driving force and wheel assembly protection; based on height sensors and hydraulic feedback, the entire process of air buoyancy start-up, wheel assembly compaction, and travel control is automated. Therefore, this invention can achieve omnidirectional movement and high-precision positioning under heavy load conditions; improve the adaptability and stability of the transport vehicle under complex ground conditions; effectively protect the wheel assembly and extend the service life of the equipment; and expand the application of air cushion transport vehicles in high-requirement scenarios such as wind tunnels and heavy equipment docking.

[0081] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0082] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A transport vehicle combining Mecanum wheels and air cushions, comprising: The vehicle body and the air cushion module disposed at the bottom of the vehicle body are characterized in that they further include: a Mecanum wheel assembly and an elastic hydraulic module; the Mecanum wheel assembly is connected to the vehicle body through the elastic hydraulic module; the elastic hydraulic module is configured to: after the air cushion module is activated to form air buoyancy, drive the Mecanum wheel assembly to descend and contact the ground, and maintain the pressure between the Mecanum wheel assembly and the ground within a preset range.

2. The transport vehicle with Mecanum wheels and air cushion combination according to claim 1, characterized in that, The elastic hydraulic module includes: a hydraulic cylinder, a hydraulic pump station, and an overflow valve; the hydraulic cylinder is a bidirectional push cylinder, its cylinder body is hinged to the vehicle body, and its piston rod end is hinged to the Mecanum wheel set; the overflow valve is located on the hydraulic cylinder on the side that controls the lifting of the entire vehicle.

3. The transport vehicle with Mecanum wheels and air cushion combination according to claim 2, characterized in that, The elastic hydraulic module also includes a pressure sensor, which is installed on the hydraulic cylinder on the side controlling the lifting of the vehicle, and is used to detect the oil pressure of the hydraulic cylinder.

4. The transport vehicle with Mecanum wheels and air cushion combination according to claim 3, characterized in that, The flexible hydraulic module further includes: a directional valve, a check valve, and a solenoid valve; the directional valve is disposed between the oil inlet and the oil outlet; the solenoid valve is disposed between the oil inlet of the directional valve and the hydraulic cylinder; and the check valve is disposed between the oil outlet of the directional valve and the hydraulic cylinder.

5. The transport vehicle with Mecanum wheels and air cushion combination according to claim 2, characterized in that, The set pressure value P of the relief valve satisfies the following relationship: 1.2F n / πr 2 ≤P≤F max / πr 2 in, Fn is the target positive pressure that the Mecanum wheel assembly needs to maintain with the ground, Fmax is the maximum positive pressure that the Mecanum wheel assembly can withstand, and r is the radius of the hydraulic cylinder.

6. The transport vehicle with Mecanum wheels and air cushion combination according to claim 1, characterized in that, The Mecanum wheel assembly includes a Mecanum wheel, a servo motor that drives the Mecanum wheel, and a speed reducer disposed between the servo motor and the Mecanum wheel.

7. A motion control method for a transport vehicle as described in any one of claims 1-6, characterized in that, include: S1: Activate the air cushion module to lift the vehicle body using air buoyancy; S2: When the vehicle body is detected to be lifted off the ground, the elastic hydraulic module is controlled to move, driving the Mecanum wheel set to descend until it contacts and compacts the ground. S3: Control the movement of the Mecanum wheelset to achieve omnidirectional movement of the transport vehicle; wherein, during the movement, the pressure between the Mecanum wheelset and the ground is maintained within a preset range through the dynamic adjustment of the elastic hydraulic module.

8. The motion control method according to claim 7, characterized in that, In step S2, the lifting status of the vehicle body off the ground is detected by a height sensor.

9. The motion control method according to claim 7, characterized in that, During the movement in step S3, when load fluctuations cause the ground pressure of the Mecanum wheel set to increase, the overflow valve in the elastic hydraulic module opens to overflow, so as to prevent the pressure from exceeding the preset maximum value; when load fluctuations cause the ground pressure to decrease, the hydraulic pump station of the elastic hydraulic module replenishes oil to the hydraulic cylinder to maintain the positive pressure.

10. The motion control method according to claim 7, characterized in that, Before step S1, adjust the overflow pressure of the elastic hydraulic module.

Images