Intelligent folding luggage trolley

Abstract

The utility model discloses an intelligent folding luggage trolley which comprises a folding box body and a driving chassis bearing the folding box body. The folding box body comprises a shell with one open end and a cover body used for sealing the shell. The cover body and the box body are connected through a plurality of telescopic rods; the telescopic rod comprises a first pipe arranged at the corner of the box body and a second pipe nested in the first pipe, a limiting groove is formed in the surface of the second pipe, and a limiting device matched with the limiting groove is arranged at the nested connection position and used for limiting the second pipe; the nylon cloth is arranged on the telescopic rods in a sleeving mode. The nylon cloth has the characteristics of foldability, tension resistance and wear resistance, and can be used as a soft shell luggage case material. Movement of the telescopic rod can be limited through the limiting device, and the function of fixing the telescopic length is achieved. Compared with a telescopic rod only with a fixed gear, the telescopic structure capable of being controlled can better meet the requirements of users under different conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of luggage carts, in particular to an intelligent folding luggage cart. Background Art

[0002] With the rapid development of modern society and the increasingly perfect transportation network, luggage has become an indispensable equipment in travel. The functions of current luggage on the market are relatively single, and it is difficult to solve various problems that users may encounter during travel, such as difficult towing due to overweight luggage, and loss of luggage. In the era of intelligentization, the intelligentization of luggage-related products has become an irresistible trend. Summary of the Utility Model

[0003] In view of this, the purpose of the present utility model is to propose an intelligent folding luggage cart, which aims at the problem of difficult towing caused by overweight luggage and proposes an intelligent folding luggage cart. Firstly, it can expand the capacity. Secondly, it can move through the driving wheel chassis. Thirdly, it can avoid obstacles and follow through the setting of sensors. The present utility model forms a multi-section box body by adding telescopic rods, increasing the available volume of the box body; designs a four-wheel drive chassis, and the luggage cart can complete actions such as turning in place by using this chassis, improving the flexibility of the luggage cart and providing mechanical support for the subsequent automatic following and obstacle avoidance of the luggage cart; reserves space for hardware integration on the cart chassis, and the intelligentization of the luggage cart can be updated by adding functional modules such as fingerprint unlocking, automatic weighing, remote alarm, and detachable lithium battery. It is hoped that the above improvements can meet the usage requirements of some users. It is expected to realize the intelligentization of the luggage.

[0004] According to one aspect of the present utility model, there is provided an intelligent folding luggage cart, comprising:

[0005] A folding box body, and a driving chassis for carrying the folding box body;

[0006] Wherein, the folding box body includes: a shell with one end open and a cover body for closing the shell; the cover body and the box body are connected by a plurality of telescopic rods; the telescopic rod includes a first tube arranged at the corner of the box body and a second tube nested in the first tube, a limiting groove is arranged on the surface of the second tube, and a limiting device cooperating with the limiting groove is arranged at the nested connection for limiting the second tube; and, a nylon cloth sleeved on each telescopic rod.

[0007] Wherein, the driving chassis adopts a four-wheel omnidirectional wheel chassis, and the area of the chassis is larger than the area of the contact surface between the box body and the chassis, and the omnidirectional wheels are arranged in an x shape.

[0008] In the above technical solution, the folding structure design is mainly to expand the available volume of the luggage. Compared with traditional luggage, the intelligent luggage requires a part of the box volume as the area for hardware integration, resulting in a reduction in the available volume. Therefore, it becomes necessary to add a folding structure. The omnidirectional wheels are arranged in an x shape, and after folding, the box is 250mm × 400mm × 600mm. Therefore, the chassis size is designed to be 400mm × 400mm. The larger chassis also provides sufficient support for the expanded box part, increasing the service life and load-bearing capacity of the folding part. The main body of the folding part of the box is a telescopic rod, and the telescopic rods are connected by nylon cloth. The nylon cloth has the characteristics of being foldable, tensile, and wear-resistant, and can be used as the material for a soft-shell luggage. The length of the telescopic rod is 200mm, and the movement of the telescopic rod can be restricted by a limiting device to achieve the function of fixing the telescopic length. Compared with the telescopic rod with only fixed gears, the controllable telescopic structure can better meet the needs of users in different situations. The thickness of the hollow rod is 2mm.

[0009] In some embodiments, the housing is made of nylon material; the cover body is made of ABS+PC material.

[0010] In the above technical solution, there are two types of hard-shell and soft-shell suitcases on the market currently. Since the chassis of the luggage trolley needs to integrate electronic components, a hard outer shell that can prevent water and moisture is adopted to avoid problems such as component short circuits and improve the service life of the luggage trolley. The main materials for the outer shell of hard-sided suitcases are the following four: acrylonitrile butadiene styrene (ABS), polypropylene (pp), polycarbonate (PC), and aluminum. Since the metal outer shell will affect the positioning signal, resulting in a decrease in positioning accuracy and the luggage trolley being unable to follow the user, the aluminum outer shell is not used. The remaining common materials for hard outer shells are ABS, PC, and ABS+PC. Among them, the ABS material has a high impact strength and can effectively resist external impacts and collisions. This enables ABS suitcases to better protect the internal items from damage during the journey. Secondly, the ABS material has good processing performance and can manufacture suitcase outer shells of various shapes and sizes through processes such as injection molding and extrusion. Finally, the cost is relatively low compared to other materials. However, the ABS material will deform or soften at higher temperatures; in a low-temperature environment, the toughness will decrease and it will become more fragile, with a risk of damage when impacted. Pure PC material has high strength and toughness and can effectively resist external impacts and extrusion. It has a good buffering effect on parts such as the top cover and bottom cover of the suitcase, making the suitcase more durable and not easily deformed. Even when encountering collisions or falls during the journey, the PC suitcase can well protect the internal items and reduce the risk of damage. At the same time, the PC suitcase has good heat resistance and cold resistance and can remain stable under various climate conditions. It can meet long-term use in different environments, but the price of PC is relatively high and it is mostly used for high-end suitcases. The ABS+PC material combines the hardness of ABS and the toughness of PC, making the suitcase outer shell able to withstand strong impacts and have excellent anti-deformation ability. This combination provides better protection for the suitcase and reduces the risk of item damage during travel. The ABS+PC suitcase can remain stable under various climate conditions and is not easily affected by temperature changes. The price is also lower than that of a pure PC material suitcase.

[0011] In summary, the hard outer shell of the present utility model is made of ABS+PC material. For the foldable part of the box body, nylon material is used to meet the foldable requirements. It should be noted that the above materials are all commonly used materials in the prior art. This case only selects materials based on the existing ones and does not involve the improvement of materials.

[0012] In some embodiments, the drive chassis is further provided with an infrared sensor and a laser obstacle avoidance sensor.

[0013] In the above technical solution, to achieve the automatic following function of the luggage cart, the positioning technology needs to be solved first. Currently, there are a wide variety of positioning technologies in widespread use, which can be classified according to the positioning implementation methods into: wireless signal positioning technology, sound positioning technology, image recognition positioning technology, and geomagnetic positioning technology. The automatic following function of the luggage cart designed in this paper is mainly applied to indoor places with a large flow of people. Indoor positioning technologies can be roughly divided into: optical motion capture technology, lidar positioning technology, UWB positioning technology, Bluetooth positioning technology, WIFI positioning technology, ultrasonic positioning technology, etc. These technologies all have their own advantages and disadvantages. The following is an analysis of the main technologies.

[0014] (1) Optical motion capture technology

[0015] This technology captures and locates the motion postures of objects or humans through optical principles. Through high-speed shooting by a computer vision sensor, retroreflective markers are pasted on the object when it is being photographed to facilitate machine positioning. A monocular vision sensor can capture the motion state of an object in a two-dimensional plane and achieve the positioning of the object in the two-dimensional plane; multiple high-speed cameras shooting from different angles can capture the position changes of the object in three-dimensional space and achieve the positioning of the object in three-dimensional space.

[0016] This technology can achieve high-precision motion capture, convert the motion trajectory of the object into digital data, and facilitate subsequent adjustment and editing. However, this technology has high requirements for light conditions, cannot be used in environments with large light changes, and has a high cost, making it not suitable for large-scale deployment.

[0017] (2) Lidar positioning technology

[0018] This technology measures parameters such as the distance, azimuth, and speed between the target and the radar by emitting a laser beam towards the target and receiving the optical signal reflected from the target. After the laser beam is reflected by the target surface, part of the optical signal will return to the radar receiver. By analyzing these reflected optical signals, detailed information about the target can be obtained.

[0019] This technology can obtain very accurate distance and angle measurement data, so it has high precision. Also, because the laser beam has the characteristics of strong directivity and narrow beam width, lidar is less affected by external electromagnetic interference and has strong anti-interference ability. The disadvantage of this technology is that in extreme weather conditions, such as heavy rain, thick fog, or snow grains, the laser beam may be scattered or absorbed, resulting in a decrease or failure of the ranging accuracy. The cost is relatively high.

[0020] (3) UWB positioning technology

[0021] This technology mainly consists of tags and base stations. Communication is carried out by transmitting ultra-short pulse signals. The system calculates the distance between the target and the receiver by measuring the propagation time difference of the transmitted signal from the transmitter to the receiver. The pulse width of this technology is extremely narrow and the signal bandwidth is large, making it easy for the receiving end to distinguish the direct path signal and simultaneously suppress or ignore multipath signals. This feature enables this technology to have a lower multipath fading in a multipath environment. Compared with other positioning technologies, it can still achieve centimeter-level positioning accuracy in the face of complex indoor environments.

[0022] (4) Bluetooth positioning technology

[0023] This technology mainly relies on RSSI (Received Signal Strength Indicator) values for positioning. By measuring the signal strength of the Bluetooth device and using signal strength positioning algorithms such as triangulation, etc., the distance between the device and the receiver can be deduced, and the specific position of the positioning device in space can be determined.

[0024] This technology has the advantages of low cost, high precision, and low power consumption. However, since Bluetooth signals are easily affected by signals of other wireless communication technologies during propagation in the 2.4GHz frequency band, it may lead to a decrease in positioning accuracy or positioning failure.

[0025] (5) Infrared positioning technology

[0026] The basic principle of infrared positioning technology includes three processes: transmitting, propagating, and receiving infrared rays. First, the infrared transmitter emits infrared signals with fixed frequencies and wavelengths. These signals propagate in the environment and are reflected or absorbed when they encounter the target object. When the receiver receives special infrared signals, they are converted into electrical signals for processing. By analyzing the processed electrical signals, the position and distance of the target object can be determined.

[0027] Since infrared signals propagate in a straight line, the positioning accuracy will decrease when the target object is blocked. The propagation of infrared signals is also easily affected by other light sources such as indoor lights and outdoor sunlight, and it is more suitable for positioning in a dark environment. This positioning technology has the advantages of small device volume and low power consumption.

[0028] By comparing the above technologies in terms of positioning accuracy, cost, anti-interference ability, device volume, and device power consumption, it can be seen that the advantages and disadvantages of different positioning technologies are not the same, and selection should be based on product requirements. Since the luggage cart is mostly used in areas with a large indoor population flow, a technology with high positioning accuracy is required; in order to reduce the self-weight of the luggage cart and load more luggage, a technology with low power consumption and small device volume needs to be used. In summary, infrared technology is selected for following positioning. The obstacle avoidance part is implemented using a laser obstacle avoidance sensor with relatively mature existing technology. This technology is an existing technology and will not be elaborated here.

[0029] In some embodiments, the motion model of the drive chassis is as follows:

[0030]

[0031] Wherein, v1 - v4 are the speeds of the four omnidirectional wheels in the four-wheel omnidirectional wheel chassis; L is the distance from the center origin of the four-wheel omnidirectional wheel chassis to the wheel center of the omnidirectional wheel; u is the speed in the X direction in the coordinate system with the luggage cart itself as the reference; v is the speed in the Y direction in the coordinate system with the luggage cart itself as the reference; ω is the rotation angle of the luggage cart itself.

[0032] In the above technical solution, by establishing a kinematic model system, the overall movement can be controlled more accurately, and the movement accuracy of the cart in space can be improved. After calculating the motion model of the luggage cart, the linear velocity v, the angular velocity ω, and the angle θ between the coordinate system of the luggage cart itself and the absolute coordinate system can be input, and then the motor speeds of the four omnidirectional wheels can be controlled, so that the luggage cart can complete actions such as turning in place and parallel movement.

[0033] In some embodiments, the drive chassis includes a bottom plate covering the surface of the chassis for receiving the box body, and the thickness of the bottom plate ≥ 5 mm.

[0034] In the above technical solution, the load-bearing capacity of a general common luggage is 20 - 30 kg, but when checked or in special situations, the bearing pressure is far greater than 30 kg. Therefore, the preset load of the intelligent folding luggage cart designed in this article is 130 kg.

[0035] In this article, the Ansys software is used to perform finite element analysis on the chassis of the luggage cart. First, the model of the luggage cart chassis is meshed, and the precise meshing should be square cells. Subsequently, the situation of applying a pressure of 1300 N on the chassis is simulated, and through this simulation process, the maximum stress value and the maximum deformation amount of the chassis under this pressure are measured. The purpose of these data is to evaluate whether the mechanical structure of the luggage cart can meet the requirements in actual applications. Based on the deformation amount nephogram of the chassis model with a load of 1300 N, it can be obtained from the analysis results that when the luggage cart chassis bears a load of 130 kg, its maximum deformation amount is 1.723 mm. Therefore, in the design of this utility model, the thickness of the cart bottom plate ≥ 5 mm. By comparing, the thickness of the luggage cart chassis is much larger than the deformation amount, so the chassis can meet the usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic structural diagram of an embodiment of an intelligent folding luggage trolley of the present utility model;

[0038] Figure 2 It is a schematic diagram of the box structure of an embodiment of an intelligent folding luggage trolley of the present utility model;

[0039] Figure 3 It is a schematic structural diagram of the telescopic rod of an embodiment of an intelligent folding luggage trolley of the present utility model;

[0040] Figure 4 It is a three-view drawing of the telescopic rod of an embodiment of an intelligent folding luggage trolley of the present utility model, where Figure ① is the front view, Figure ② is the top view, and Figure ③ is the side view;

[0041] Figure 5 It is a schematic structural diagram of the chassis of an embodiment of an intelligent folding luggage trolley of the present utility model;

[0042] Figure 6 It is a schematic diagram of the omnidirectional wheels arranged in an x shape of an embodiment of an intelligent folding luggage trolley of the present utility model;

[0043] Figure 7 It is a schematic diagram of the self-coordinates and absolute coordinates of an intelligent folding luggage trolley of an embodiment of the present utility model. Specific embodiments

[0044] The following will further describe the present utility model in detail in conjunction with the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present utility model, but do not limit the scope of the present utility model. Similarly, the following embodiments are only partial embodiments of the present utility model rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

[0045] The purpose of the present utility model is to provide an intelligent folding luggage trolley. In view of the problem of difficult towing caused by overweight luggage, an intelligent folding luggage trolley is proposed. Firstly, it can expand the capacity. Secondly, it can move through the driving wheel chassis. Thirdly, it can avoid obstacles and follow by setting sensors. The present utility model increases the telescopic rod to form a multi-section box body, increasing the available volume of the box body; designs a four-wheel drive chassis, and with this chassis, the luggage trolley can complete actions such as turning in place, improving the flexibility of the luggage trolley and providing mechanical support for the subsequent automatic following and obstacle avoidance of the luggage trolley; reserves space for hardware integration on the trolley chassis, and can update the intelligence of the luggage trolley by adding functional modules such as fingerprint unlocking, automatic weighing, long-distance alarm, and detachable lithium battery. It is hoped that the above improvements can meet the usage needs of some users and achieve the intelligence of the luggage trolley.

[0046] One of the embodiments

[0047] Please refer to Figure 1 , an intelligent folding luggage trolley, comprising: a folding box body 1 and a driving chassis 2 carrying the folding box body 1;

[0048] Among them, please refer to Figure 2 , the folding box body 1 includes: a shell 11 with one end open and a cover body 12 for closing the shell; the cover body 12 and the box body 11 are connected by a plurality of telescopic rods 13;

[0049] Please refer to Figure 2 , Figure 3 , the telescopic rod 13 includes a first tube 131 arranged at the corner of the box body 11 and a second tube 132 nested in the first tube 131. A limiting groove 1321 is arranged on the surface of the second tube 132, and a limiting device 133 matching the limiting groove 1321 is arranged at the nested connection for limiting the second tube 132; and, a nylon cloth (not shown in the figure) sleeved on each telescopic rod;

[0050] Among them, for the specific structure of the telescopic rod, please refer to Figure 4, In the figure, 131 is the first tube, which is an air tube; 132 is the second tube, which is a solid tube; 1331 is a limiting ring sleeved on the second tube 132; 1332 is a wrench; 1333 is a pin, and 1334 is a limiting block. Specifically, the limiting ring 1332 is sleeved on the second tube 132, and one side is fixed at the connection of the first tube 131 and the second tube 132. Inside the limiting ring 1332, a wrench 1332 is rotatably arranged, and a limiting block 1334 that abuts against the wrench 1332. By rotating the wrench to press the limiting block 1332 downward into the limiting groove 132, the friction force is increased to limit the movement of the second tube 132. Since only limiting is required in this case and not excessive load, it can be achieved by simple friction force limiting and cannot have a too complex structure. The length of the telescopic rod is 200 mm. By pressing the wrench, the lower elliptical part of the wrench rotates to squeeze the limiting block. Under the combined action of the limiting block and the limiting ring, the movement of the telescopic rod is restricted, achieving the function of fixing the telescopic length. Compared with a telescopic rod with only fixed gears, a controllable telescopic structure can better meet the needs of users in different situations. The thickness of the hollow rod is 2 mm.

[0051] Among them, please refer to Figure 5 、 Figure 6 , The driving chassis 2 adopts a four-wheel omnidirectional wheel chassis, and the chassis area is larger than the contact area between the box body and the chassis, and the omnidirectional wheels are arranged in an x shape. The trolley chassis needs to store a micro motor for driving the omnidirectional wheels to facilitate the automatic following of the suitcase; an MCU with an ultra-distance alarm function; a strain pressure sensor with a fingerprint function and a pressure sensor signal conversion module. The trolley chassis mainly consists of a bottom plate 21, a cavity 22, four omnidirectional wheels 23, and a driving motor 24 connected to the four omnidirectional wheels. Among them, the thickness of the trolley bottom plate and the bottom plate cover is 5 mm; the motor is connected to the trolley chassis through a bending part and an inner hexagon socket head cap screw; the motor is connected to the omnidirectional wheel through a motor shaft so that the motor can control the rotation of the omnidirectional wheel. It should be noted that the driving program, driving circuit, and method are prior arts and will not be described in this embodiment. Those skilled in the art can select models according to actual needs.

[0052] In this embodiment, the load-bearing capacity of a general common suitcase is 20 - 30 kg, but when checked or in special situations, the bearing pressure is far greater than 30 kg. Therefore, the intelligent folding luggage trolley designed in this article has a preset load of 130 kg.

[0053] In this article, the Ansys software is used to perform finite element analysis on the chassis of the luggage cart. First, the model of the luggage cart chassis is meshed, and the precise mesh should be square cells. Subsequently, the situation of applying a pressure of 1300 N on the chassis is simulated, and through this simulation process, the maximum stress value and the maximum deformation amount of the chassis under this pressure are measured. The purpose of these data is to evaluate whether the mechanical structure of the luggage cart can meet the requirements in actual applications. Based on the deformation amount nephogram of the chassis model with a load of 1300 N, it can be obtained from the analysis results that when the luggage cart chassis bears a weight of 130 kg, its maximum deformation amount is 1.723 mm. Therefore, in the design of this utility model, the thickness of the cart bottom plate ≥ 5 mm. By comparing, the thickness of the luggage cart chassis is much larger than the deformation amount, so the chassis can meet the usage requirements.

[0054] In this embodiment, to achieve the automatic following function of the luggage cart, first, the universal wheels of the luggage are replaced with a driving device that can provide forward power through motor drive. For example, a four-wheel Ackermann chassis, a four-wheel skid chassis, a four-wheel Mecanum wheel chassis, a four-wheel omnidirectional wheel chassis, etc. can be used.

[0055] Since the usage scenarios of the luggage cart are mostly crowded places, when following the user's movement, it is easy to encounter situations where pedestrians in front stop or the space is small. It takes a long time to bypass or wait in place, and it is easy to lose the following target. Therefore, there is a high demand for the sensitivity of the luggage cart's movement.

[0056] The Ackermann chassis is similar to an automobile chassis. The front wheels control the movement direction of the cart, and the rear wheels are responsible for providing power. Steering is completed through the differential of the rear wheels. This chassis requires a large steering space, so the Ackermann chassis is excluded.

[0057] The skid chassis, usually also known as a four-wheel differential chassis, its working principle is to achieve the steering function through the speed difference between the left and right wheels. In this chassis design, the positions of the four wheels are fixed. When the vehicle performs differential steering in place, since the axle does not pass through the rotation center, it will be significantly affected by external friction factors. This design makes the wheels prone to lateral sliding during operation, especially under rough ground conditions, and the tire wear will be more serious. Therefore, the four-wheel differential chassis is excluded.

[0058] Both the Mecanum wheel chassis and the omnidirectional wheel chassis can enable the cart to move in all directions, with very high flexibility and can meet the luggage cart to follow the user in a narrow space. However, there are also some differences between them. Among them, the Mecanum wheels are mostly made of metal, with high manufacturing process and cost, short service life, and require regular maintenance, etc. In contrast, the omnidirectional wheel chassis can be made of plastic, with low cost and long service life. In summary, the four-wheel omnidirectional wheel chassis is adopted.

[0059] In this embodiment, the folding structure is designed mainly to expand the available volume of the luggage. Compared with traditional luggage, the intelligent luggage requires a part of the box volume as the area for hardware integration, resulting in a reduction in the available volume. Therefore, it becomes necessary to add a folding structure. The omnidirectional wheels are arranged in an x shape. After folding, the box is 250mm×400mm×600mm. Therefore, the chassis size is designed to be 400mm×400mm. The larger chassis also provides sufficient support for the expanded box part, increasing the service life and load-bearing capacity of the folding part. The main body of the folding part of the box is a telescopic rod, and the telescopic rods are connected by nylon cloth. The nylon cloth has the characteristics of being foldable, tensile, wear-resistant, and can be used as the material for a soft-shell luggage. The length of the telescopic rod is 200mm, and the movement of the telescopic rod can be restricted by a limiting device to achieve the function of fixing the telescopic length. Compared with the telescopic rod with only fixed gears, the controllable telescopic structure can better meet the needs of users in different situations. The thickness of the hollow rod is 2mm.

[0060] In this embodiment, the housing is made of nylon material; the cover is made of ABS+PC material. Currently, there are two types of hard-shell and soft-shell luggage on the market. Since the chassis of the luggage cart needs to integrate electronic components, a hard shell that can prevent water and moisture is used to avoid problems such as component short circuits and improve the service life of the luggage cart. The main materials for the hard shell of the luggage cart are the following four: acrylonitrile butadiene styrene (ABS), polypropylene (pp), polycarbonate (PC), and aluminum. Since the metal shell will affect the positioning signal, resulting in a decrease in positioning accuracy and the luggage cart being unable to follow the user, an aluminum shell is not used. The common materials for the remaining hard shells are ABS, PC, and ABS+PC. Among them, the ABS material has a high impact strength and can effectively resist external impacts and collisions. This enables the ABS luggage to better protect the internal items from damage during the journey. Secondly, the ABS material has good processing performance and can be used to manufacture luggage shells of various shapes and sizes through processes such as injection molding and extrusion. Finally, the cost is relatively low compared to other materials. However, the ABS material will deform or soften at higher temperatures; in a low-temperature environment, the toughness will decrease and it will become more fragile, with a risk of damage when impacted. The pure PC material has high strength and toughness and can effectively resist external impacts and extrusion. It has a good buffering effect on parts such as the top cover and bottom cover of the luggage, making the luggage more durable and not easily deformed. Even when encountering collisions or falls during the journey, the PC luggage can well protect the internal items and reduce the risk of damage. At the same time, the PC luggage has good heat resistance and cold resistance and can remain stable under various climate conditions. It can meet long-term use in different environments, but the price of PC is relatively high and it is mostly used for high-end luggage. The ABS+PC material combines the hardness of ABS and the toughness of PC, making the luggage shell able to withstand strong impacts and have excellent anti-deformation ability. This combination provides better protection for the luggage and reduces the risk of item damage during travel. The ABS+PC luggage can remain stable under various climate conditions and is not easily affected by temperature changes. The price is also lower than that of the pure PC material box.

[0061] In summary, the hard case shell of the present utility model is made of ABS+PC material. For the foldable part of the case, nylon material is used to meet the folding requirements. It should be noted that the above materials are all commonly used materials in the prior art. This case only selects materials based on the existing ones and does not involve the improvement of materials. At the same time, in this case, a mechanical simulation of the chassis is carried out. From the simulation results, the maximum stress value of the chassis is 12.31 MPa. By referring to the data, the yield strength of nylon PA66 is about 54.88 MPa. By comparison, the maximum stress value is still less than the yield strength, so the chassis has sufficient strength. After in-depth analysis and testing, it is found that even when the chassis needs to bear a load of up to 130 kg under extreme conditions, its stiffness and strength can be maintained within the design standards. Whether in the event of a sudden accident or during daily use, the chassis can stably and reliably support the required load without worrying about deformation or damage to its structure.

[0062] In this embodiment, the driving chassis is further provided with an infrared sensor and a laser obstacle avoidance sensor (not shown in the figure, and those skilled in the art can design the layout position of the sensors according to actual needs, which is not limited in this embodiment). In this embodiment, to achieve the automatic following function of the luggage cart, the positioning technology needs to be solved first. Currently, there are a wide variety of positioning technologies in wide use, which can be classified according to the positioning implementation methods into: wireless signal positioning technology, sound positioning technology, image recognition positioning technology, and geomagnetic positioning technology. The automatic following function of the luggage cart designed in this article is mainly applied to indoor places with a large number of people. Indoor positioning technologies can be roughly divided into: optical motion capture technology, lidar positioning technology, UWB positioning technology, Bluetooth positioning technology, WIFI positioning technology, ultrasonic positioning technology, etc. These technologies all have their own advantages and disadvantages. The following is an analysis of the main technologies.

[0063] (1) Optical motion capture technology

[0064] This technology captures and locates the motion postures of objects or humans through optical principles. Through a computer vision sensor for high-speed shooting, a reflective marker is pasted on the object when it is being photographed for the machine to locate. A monocular vision sensor can capture the motion state of an object in a two-dimensional plane and achieve the positioning of the object in the two-dimensional plane; multiple high-speed cameras shooting from different angles can capture the position changes of an object in a three-dimensional space and achieve the positioning of the object in the three-dimensional space.

[0065] This technology can achieve high-precision motion capture, convert the motion trajectory of an object into digital data, and facilitate subsequent adjustment and editing. However, this technology has high requirements for light conditions, cannot be used in an environment with large light changes, and has a high cost, so it is not suitable for large-scale layout.

[0066] (2) Lidar positioning technology

[0067] This technology measures parameters such as the distance, azimuth, and speed between the target and the radar by emitting a laser beam towards the target and receiving the optical signal reflected from the target. After the laser beam is reflected by the target surface, part of the optical signal will return to the radar receiver. By analyzing these reflected optical signals, detailed information about the target can be obtained.

[0068] This technology can obtain very accurate distance and angle measurement data, so it has high precision. Also, because the laser beam has the characteristics of strong directivity and narrow beam width, lidar is less affected by external electromagnetic interference and has strong anti-interference ability. The disadvantages of this technology are that in extreme weather conditions, such as heavy rain, thick fog, or snow grains, the laser beam may be scattered or absorbed, resulting in a decrease or failure of the ranging accuracy. The cost is relatively high.

[0069] (3) UWB positioning technology

[0070] This technology mainly consists of tags and base stations. It communicates by transmitting ultra-short pulse signals. The system calculates the distance between the target and the receiver by measuring the propagation time difference of the transmitted signal from the transmitter to the receiver. The pulse width of this technology is extremely narrow and the signal bandwidth is large. The receiving end can easily distinguish the direct path signal and simultaneously suppress or ignore the multipath signals, which makes this technology have lower multipath fading in a multipath environment. Compared with other positioning technologies, it can still achieve centimeter-level positioning accuracy in the face of complex indoor environments.

[0071] (4) Bluetooth positioning technology

[0072] This technology mainly relies on the RSSI (Received Signal Strength Indicator) value for positioning. By measuring the signal strength of the Bluetooth device and using signal strength positioning algorithms such as triangulation method, etc., the distance between the device and the receiver can be deduced, and the specific position of the positioning device in space can be determined.

[0073] This technology has the advantages of low cost, high precision, and low power consumption. However, since Bluetooth signals are easily affected by signals of other wireless communication technologies during propagation in the 2.4GHz frequency band, it may lead to a decrease in positioning accuracy or positioning failure.

[0074] (5) Infrared positioning technology

[0075] The basic principle of infrared positioning technology includes three processes: emitting, propagating, and receiving infrared rays. First, the infrared emitter emits infrared signals with fixed frequencies and wavelengths. These signals propagate in the environment and are reflected or absorbed when encountering the target object. When the receiver receives special infrared signals, it converts them into electrical signals for processing. By analyzing the processed electrical signals, the position and distance of the target object can be determined.

[0076] Since infrared signals propagate in a straight line, the positioning accuracy will decrease when the target object is blocked. The propagation of infrared signals is also easily affected by other light sources, such as indoor lights and outdoor sunlight, and is more suitable for positioning in a dark environment. This positioning technology has the advantages of small device size and low power consumption.

[0077] Comparing the above technologies in terms of positioning accuracy, cost, anti-interference ability, device size, and device power consumption, it can be seen that the advantages and disadvantages of different positioning technologies are not the same, and should be selected according to product requirements. Since the luggage trolley is mostly used in indoor areas with a large flow of people, a technology with high positioning accuracy is required; in order to reduce the self-weight of the luggage trolley and load more luggage, a technology with low power consumption and small device size needs to be used. To sum up, infrared technology is selected for follow-up positioning. The obstacle avoidance part is realized by using a laser obstacle avoidance sensor with relatively mature existing technology. This technology is an existing technology and will not be elaborated here.

[0078] In this embodiment, the motion model of the driving chassis is as follows:

[0079]

[0080] In the formula, v1 - v4 are the speeds of the four omnidirectional wheels in the four-wheel omnidirectional wheel chassis; L is the distance from the center origin of the four-wheel omnidirectional wheel chassis to the center of the omnidirectional wheel; u is the speed in the X direction in the coordinate system with the luggage trolley itself as the origin; v is the speed in the Y direction in the coordinate system with the luggage trolley itself as the origin; ω is the rotation angle of the luggage trolley.

[0081] The above model is derived as follows:

[0082] Please refer to Figure 7 , and conduct a motion model analysis based on the designed luggage trolley chassis. As shown in the figure, taking the midpoint of the luggage trolley chassis as the coordinate origin, a rectangular coordinate system XOY is established, where X1: the speed of the luggage trolley in the X direction in the absolute coordinate system; Y1: the speed of the luggage trolley in the Y direction in the absolute coordinate system; u: the speed in the X direction in the coordinate system with the luggage trolley itself as the origin; v: the speed in the Y direction in the coordinate system with the luggage trolley itself as the origin; θ: the angle between the coordinate system of the luggage trolley itself and the absolute coordinate system; ω: the rotation angle of the luggage trolley; L: the distance from the origin of the luggage trolley's own coordinate to the omnidirectional wheel; v1 - v4: the speeds of the four wheels.

[0083] Orthogonally decompose the coordinates u and v of the luggage trolley into the absolute coordinates to obtain the following formula

[0084] u = X1cosθ + Y1sinθ

[0085] v = X1cosθ - Y1sinθ

[0086] It is convenient to calculate and convert the above formula into matrix form as follows

[0087]

[0088] According to the omnidirectional wheel chassis form, the geometric relationship between the four omnidirectional wheels and the chassis can be obtained, and the kinematic equation of the motor-driven luggage cart is as follows

[0089]

[0090] Convert the above formula into matrix form, and the motion model of the luggage cart is obtained as follows

[0091]

[0092] By establishing a kinematic model system, the overall movement can be controlled more accurately, and the movement accuracy of the cart in space can be improved. After calculating the motion model of the luggage cart, the linear velocity v, angular velocity ω, and the angle θ between the self-coordinate system of the luggage cart and the absolute coordinate system can be input, and then the motor speeds of the four omnidirectional wheels can be controlled, so that the luggage cart can complete actions such as turning in place and parallel movement. The movement of the four-wheel omnidirectional wheel cart requires four motors to control the movement directions and speeds of the independent omnidirectional wheels respectively to achieve the movement of the omnidirectional wheel cart in any direction. Since each omnidirectional wheel needs to be controlled, a kinematic model is established for the omnidirectional wheel chassis. This model can help establish the relationship between the overall space of the luggage cart and the motor-controlled omnidirectional wheels, which is convenient for converting the spatial position information received by the infrared sensor into the output signal of the motor to control the rotation direction and speed of the omnidirectional wheels, and better control accuracy can be obtained. In this embodiment, by establishing a kinematic model system, the overall movement can be controlled more accurately, and the movement accuracy of the cart in space can be improved. After calculating the motion model of the luggage cart, the linear velocity v, angular velocity ω, and the angle θ between the self-coordinate system of the luggage cart and the absolute coordinate system can be input, and then the motor speeds of the four omnidirectional wheels can be controlled, so that the luggage cart can complete actions such as turning in place and parallel movement. The obstacle avoidance part is implemented by using a relatively mature laser obstacle avoidance sensor in the existing technology. This technology is the existing technology, and the principle and implementation method of obstacle avoidance will not be elaborated here too much.

[0093] The above are only some embodiments of the present invention, and thus do not limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An intelligent folding luggage trolley, characterized in that, Comprising: A folding box body, and a driving chassis for carrying the folding box body; Wherein, the folding box body includes: a housing with one end open and a cover body for closing the housing; the cover body and the box body are connected by a number of telescopic rods; the telescopic rod includes a first tube disposed at the corner of the box body and a second tube nested in the first tube, a limiting groove is provided on the surface of the second tube, and a limiting device cooperating with the limiting groove is provided at the nested connection for limiting the second tube; and, a nylon cloth sleeved on each telescopic rod; Wherein, the driving chassis adopts a four-wheel omnidirectional wheel chassis, and the chassis area is larger than the area of the contact surface between the box body and the chassis, and the omnidirectional wheels are arranged in an x shape.

2. The intelligent folding luggage trolley according to claim 1, wherein The housing is made of nylon material; The cover body is made of ABS+PC material.

3. The intelligent folding luggage trolley according to claim 1, wherein The driving chassis is further provided with an infrared sensor and a laser obstacle avoidance sensor.

4. The intelligent folding luggage trolley according to claim 1, wherein The motion model of the driving chassis is as follows: In the formula, v1-v4 are the speeds of the four omnidirectional wheels in the four-wheel omnidirectional wheel chassis; L is the distance from the center origin of the four-wheel omnidirectional wheel chassis to the wheel center of the omnidirectional wheel; u is the speed in the X direction in the coordinate system with the luggage trolley itself as the reference; v is the speed in the Y direction in the coordinate system with the luggage trolley itself as the reference; ω is the rotation angle of the luggage trolley.

5. The intelligent folding luggage trolley according to claim 1, wherein The driving chassis includes a bottom plate covering the surface of the chassis for receiving the box body, and the thickness of the bottom plate ≥5mm.

Images