A wheelchair suitable for people with mild disabilities

Abstract

The present invention provides a wheelchair suitable for people with mild disabilities, comprising at least a first front wheel and a second front wheel, which are coaxial with each other and arranged along the body direction of the wheelchair, and a first rear wheel and a second rear wheel, which are coaxial with each other. The first front wheel and the second front wheel are Mecanum wheels. The first rear wheel and the second rear wheel are straight-running wheels. Independent dual motors are used to drive the straight-running wheels as rear wheels and driving wheels respectively, and Mecanum wheels are used as front wheels and driven wheels, which cooperate with the driving wheels of the straight-running wheels. Different from the differential steering control system of the prior art in which all wheels are straight-running wheels, the wheelchair can be adjusted in the direction of travel and the lateral speed only by regulating the speed and speed difference of the first motor and the second motor to drive the first rear wheel and the second rear wheel respectively. The control variables are few, and the control accuracy can also meet the general needs of wheelchairs for people with mild disabilities. The structure is simple and it is convenient for people with mild disabilities to be generally applicable.

Description

Technical Field

[0001] The present invention relates to the field of wheelchairs, and in particular to a wheelchair suitable for people with mild disabilities, and more specifically to an electric wheelchair and a control method thereof. Background Art

[0002] China is gradually entering an aging society. The seventh census data shows that China has a population of 264.02 million people aged 60 and above, accounting for 18.70%; among them, the population aged 65 and above is 190.64 million, accounting for 13.50%. Improving the quality of life of the elderly and caring for the elderly have become important social issues. As the elderly grow older, a considerable number of them have difficulty walking and walking, which affects their normal activities outside. Therefore, providing the elderly with a low-cost, easy-to-operate and stable means of transportation is an important part of implementing the policy of caring for the elderly. In addition, there are currently 24.72 million people with physical disabilities in my country. In addition to the elderly, people with lower limb disabilities or patients with temporary mobility difficulties also have the same needs.

[0003] Wheelchairs are an important aid for the disabled and an ideal means of transportation for the elderly with mobility problems. However, ordinary wheelchairs generally need to be driven by the upper limb strength of the rider or pushed by others. In developed countries such as Europe and the United States, manual wheelchairs have been gradually phased out and replaced by electric wheelchairs with superior performance, easy operation, safe and reliable operation. With the development of the economy and the improvement of people's living standards, my country has gradually developed a demand for electric wheelchairs. As a new type of transportation, electric wheelchairs have broad market prospects and social significance.

[0004] The electric wheelchair developed by Pride Company in the United States uses two brushed DC motors as its driving motors, and the controller installed in the joystick realizes the straight and turning of the wheelchair. The electric wheelchair is easy to operate and has a small radius, which is suitable for indoor use. The Technical University of Aachen, Germany has developed an intelligent electric wheelchair. The wheelchair is equipped with a small computer and a camera. The camera focuses on the user's facial movements, generates dozens of images per second and transmits them to the small computer. The computer processes the image, analyzes the feature points of the eyebrows, corners of the eyes, corners of the mouth and other parts, and tracks the position changes of these feature points at any time, determines the movements of each part, and then issues corresponding control instructions based on these movements, commanding the wheelchair to move forward, stop, turn left or right, etc. This wheelchair can not only help the elderly and mildly disabled people, but also help those severely paralyzed patients who cannot move below the cervical spine. The Industrial Science and Technology Agency of Japan has successfully developed an electric wheelchair equipped with a microcomputer. When a disabled person cannot use his or her hands and feet, this wheelchair uses a joystick and voice control system to make the wheelchair move in a straight line and turn horizontally through commands. At the same time, it can be raised to the height at which an average person stands, making it convenient for the disabled person's daily work and life.

[0005] Chinese patent CN102697609B discloses an electric wheelchair and its steering control device. The electric wheelchair includes a front bracket, a rear bracket, a main bracket and a seat bracket, a running device includes a pair of front wheels and a rear wheel, and a steering control device includes: a closed flexible connector with a certain strength and three pairs of guide wheels for supporting and guiding the flexible connector; the flexible connector is wrapped around and sleeved on the rotating shaft of the rear wheel to drive the rear wheel to turn; the flexible connector extending from the rotating shaft extends forward and outward to the first guide wheel, then forward to the second guide wheel; and then backward to the third guide wheel, and an operating handle is connected to the second guide wheel coaxially, so as to drive the flexible connector to wrap around the second guide wheel by operating the operating handle; the flexible connector extending from the third guide wheel extends horizontally to the third guide wheel on the opposite side.

[0006] Chinese patent CN103735375B discloses a universal movement conversion mechanism for an electric wheelchair, including a rotating shaft fixing plate, a universal load-bearing wheel mounting member, a universal load-bearing wheel, a mounting cylinder, a support rod, a footboard, a top block, and a rotating shaft. Two rotating shaft fixing plates and two mounting cylinders are respectively fixedly connected to the base of the electric wheelchair, the rotating shaft passes through the rotating shaft fixing plate, and the two ends of the rotating shaft are respectively fixedly connected to the footboard, a top block is provided at the upper end of the mounting cylinder, and the top block is fixedly connected to the rotating shaft, the mounting cylinder is connected to the support rod through a spring, the lower end of the support rod passes through the mounting cylinder and is fixedly connected to the universal load-bearing wheel mounting member, the upper end surface of the support rod is in contact with the top block, and the universal load-bearing wheel is installed below the universal load-bearing wheel mounting member.

[0007] The above-mentioned prior art wheelchairs have relatively complex and imperfect control of travel direction, speed and steering. The real-time, accuracy and convenience of the control need to be improved, especially independent direction control components and speed control components are required, and the control algorithm is relatively complex. At the same time, the obstacle crossing performance of the wheel body and the overall anti-vibration performance of the wheelchair in the prior art are also relatively lacking. There is a need for a wheelchair that can meet the needs of people with mild disabilities in an economically effective way, with a simple structure and control method, easy to operate, and with improved obstacle crossing and shock absorption performance.

[0008] In addition, on the one hand, the technical personnel understood by the applicant and the examination department are bound to be different; on the other hand, the inventor studied a large number of documents and patents when making the present invention, but due to space limitations, not all details and contents are listed in detail. However, this does not mean that the present invention does not have the characteristics of these prior arts. On the contrary, the present invention already has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art to the background technology at any time in accordance with the relevant provisions of the examination guidelines. Summary of the invention

[0009] The present invention provides a wheelchair, which may be a manual wheelchair, an electric wheelchair, or a wheelchair with manual and electric switch control.

[0010] In a first aspect, the present invention provides a wheelchair suitable for people with mild disabilities, comprising at least a first front wheel and a second front wheel coaxially arranged along the body direction of the wheelchair, and a first rear wheel and a second rear wheel coaxially arranged along the body direction of the wheelchair. The first front wheel and the second front wheel are Mecanum wheels. The first rear wheel and the second rear wheel are straight-running wheels.

[0011] According to a preferred embodiment, the first front wheel and the second front wheel are driven wheels, and the first rear wheel and the second rear wheel are driving wheels.

[0012] According to a preferred embodiment, the first rear wheel and the second rear wheel are controlled by a first motor and a second motor respectively which are independent of each other.

[0013] According to a preferred embodiment, during the movement, the speed of the first rear wheel is v1, the speed of the second rear wheel is v2, and when v1=v2, the wheelchair moves forward or backward along the direction of the vehicle body.

[0014] According to a preferred embodiment, when v1<v2, the wheelchair moves toward one side of the first rear wheel. When v1>v2, the wheelchair moves toward one side of the second rear wheel.

[0015] According to a preferred embodiment, the greater the difference between v1 and v2, the greater the speed of the wheelchair moving toward the first rear wheel or the second rear wheel. The smaller the difference between v1 and v2, the smaller the speed of the wheelchair moving toward the first rear wheel or the second rear wheel.

[0016] According to a preferred embodiment, the radii of the first front wheel and the second front wheel are both r1, and the radii of the first rear wheel and the second rear wheel are both r2, wherein r1≤r2.

[0017] According to a preferred embodiment, the distance between the first front wheel and the second front wheel is d1, and the distance between the first rear wheel and the second rear wheel is d2, wherein d1≤d2.

[0018] A second aspect of the present invention provides a wheelchair, comprising at least a first front wheel and a second front wheel, and a first rear wheel and a second rear wheel, which are coaxial with each other and arranged along the body direction of the wheelchair. The wheelchair changes the direction of travel of the wheelchair by the speed difference between the first rear wheel and the second rear wheel.

[0019] According to a preferred embodiment, the wheelchair adjusts the lateral movement speed of the wheelchair by adjusting the speed difference between the first rear wheel and the second rear wheel.

[0020] The beneficial technical effects of the present invention include:

[0021] Independent dual motors are used to drive the straight-running wheels as rear wheels and driving wheels respectively, and Mecanum wheels are used as front wheels and driven wheels, which cooperate with the driving wheels of the straight-running wheels. Different from the differential steering control system in the prior art in which all the wheels are straight-running wheels, it is only necessary to regulate the speeds and speed difference of the first motor and the second motor to drive the first rear wheel and the second rear wheel respectively, so as to adjust the travel direction and lateral speed of the wheelchair. There are few control variables, and the control accuracy can also meet the general needs of wheelchairs for people with mild disabilities. The structure is simple, and it is convenient for people with mild disabilities to generally apply it. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a preferred embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of a preferred embodiment of the first convex portion and the first concave portion of the present invention.

[0024] Reference numerals list

[0025] 101: First front wheel 102: Second front wheel

[0026] 103: First rear wheel 104: Second rear wheel

[0027] 105: First concave portion 106: First convex portion DETAILED DESCRIPTION

[0028] The following is combined with Figure 1 and attached Figure 2 Provide detailed explanation.

[0029] Example 1

[0030] The present embodiment discloses a wheelchair suitable for people with mild disabilities, which can also be a transport device or a mobile device. The wheelchair of the present embodiment includes a support part for supporting the entire wheelchair, a seat part that can directly contact the user's body and support his body parts, a moving part for realizing the movement and stop of the wheelchair, and a control part for realizing the start, stop and steering of the wheelchair.

[0031] Preferably, the moving part includes a first front wheel 101 and a second front wheel 102 coaxially arranged along the body direction of the wheelchair, a first rear wheel 103 and a second rear wheel 104 coaxially arranged along the body direction of the wheelchair, and a braking device. Preferably, the seat part includes a seat cushion, a backrest, an armrest and a pedal. Preferably, the supporting part includes a front frame body connected to and accommodating the first front wheel 101 and the second front wheel 102, a rear frame body connected to and accommodating the first rear wheel 103 and the second rear wheel 104, a main frame body supporting the seat part and a bottom plate. The control part includes an operating unit, an actuating unit, a flexible connector and a guide wheel supporting or winding the flexible connector.

[0032] Preferably, the first front wheel 101 and the second front wheel 102 are Mecanum wheels. The first rear wheel 103 and the second rear wheel 104 are straight-running wheels. The first front wheel 101 and the second front wheel 102 are driven wheels. The first rear wheel 103 and the second rear wheel 104 are driving wheels. A Mecanum wheel is a component of a central wheel having a plurality of axles located around the wheel. The angled peripheral axles convert a portion of the wheel steering force into the wheel normal force. Depending on the direction and speed of each wheel, the final synthesis of these forces produces a resultant force vector in any desired direction, thereby ensuring that the platform can move freely in the direction of the final resultant force vector without changing the direction of the wheel itself. Many small rollers are obliquely distributed on its wheel rim, so the wheel can slide laterally. The generatrix of the small rollers is special. When the wheel rotates around the fixed wheel axle, the envelope of each small roller is a cylindrical surface, so the wheel can roll forward continuously.

[0033] Preferably, the actuating unit includes a first motor and a second motor. The first motor and the second motor are arranged on the bottom plate. The first rear wheel 103 and the second rear wheel 104 are driven and controlled by the first motor and the second motor, respectively, which are independent of each other. In the turning process of ordinary straight-running wheels, the contradiction between the equal rotation speeds and different strokes of the left and right driving wheels causes a certain driving wheel to slip or slide, which causes the tire to wear prematurely and consumes power unnecessarily. In this embodiment, the wheelchair can move forward, backward and turn by arranging straight-running wheels as driving wheels and Mecanum wheels as driven wheels, which are independently driven by motors, to cooperate with each other. During the turning process, the Mecanum wheels themselves do not deflect.

[0034] Preferably, during the travel, the speed of the first rear wheel 103 is v1, and the speed of the second rear wheel 104 is v2. When v1=v2, the wheelchair moves forward or backward along the direction of the vehicle body. Preferably, when v1<v2, the wheelchair moves toward one side of the first rear wheel 103. When v1>v2, the wheelchair moves toward one side of the second rear wheel 104. Preferably, the greater the difference between v1 and v2, the greater the travel speed of the wheelchair toward the first rear wheel or the second rear wheel. The smaller the difference between v1 and v2, the smaller the travel speed of the wheelchair toward the first rear wheel or the second rear wheel.

[0035] Preferably, when the wheelchair of this embodiment needs to move forward during driving, the operating unit can be moved forward. At this time, the first motor and the second motor provide the same driving force for rolling forward to the first rear wheel 103 and the second rear wheel 104 respectively, and the first rear wheel 103 and the second rear wheel 104 thereby drive the first front wheel 101 and the second front wheel 102, and the wheelchair as a whole moves forward. When the wheelchair needs to move backward during driving, the operating unit can be moved backward. At this time, the first motor and the second motor provide the same driving force for rolling backward to the first rear wheel 103 and the second rear wheel 104 respectively, and the first rear wheel 103 and the second rear wheel 104 thereby drive the first front wheel 101 and the second front wheel 102, and the wheelchair as a whole moves backward.

[0036] Preferably, when the wheelchair needs to move to the left during travel, the operating unit can be moved to the left. At this time, the first motor drives the first rear wheel 103 to have a speed v1, and the second motor drives the second rear wheel 104 to have a speed v2, where v1 is less than v2, so that the wheelchair moves to the left. When the wheelchair needs to move to the right during travel, the operating unit can be moved to the right. The first motor drives the first rear wheel 103 to have a speed v1, and the second motor drives the second rear wheel 104 to have a speed v2, where v1 is greater than v2, so that the wheelchair moves to the right. When braking is required, the operating unit is returned to its original position, and the first motor and the second motor gradually reduce the driving force of the first rear wheel and the second rear wheel to zero. At the same time, the braking device is activated to achieve braking of the wheelchair in a way that avoids sudden stops, thereby improving the comfort of the user and reducing the risk of the occupant flying out of the wheelchair when the wheelchair decelerates, thereby protecting the personal safety of the occupant.

[0037] Preferably, the brake device of the moving part of the wheelchair controls the wheelchair to decelerate in the following control method to avoid the wheelchair from stopping suddenly:

[0038] When a braking command is received, the moving speed of the wheelchair is detected;

[0039] When the moving speed of the wheelchair is greater than the first threshold, the control performs intermittent braking at a set braking frequency to maintain the acceleration difference between the passenger and the wheelchair, so as to avoid the speed difference between the passenger and the wheelchair being too large and causing the user to have a relative displacement with the wheelchair during the braking process, that is, to slide out of the wheelchair; wherein the braking frequency and the duration of each braking are determined by the acceleration difference between the passenger and the wheelchair within the second detection period T; when the acceleration of the wheelchair is greater than the acceleration of the passenger, the duration of each braking is shortened to reduce the speed change difference between the passenger and the wheelchair, so as to avoid the passenger having a relative displacement with respect to the wheelchair and flying out from the front of the wheelchair;

[0040] When the moving speed of the wheelchair is less than the first threshold, the braking is controlled to continue.

[0041] Preferably, the second detection period T is at most 1 / 2 of the braking period.

[0042] The advantage of this arrangement is that it can ensure the safety of the wheelchair occupant and the deceleration efficiency of the wheelchair. The intermittent braking method can ensure that the wheels of the wheelchair will not lock, avoiding the risk of the wheelchair slipping; and this method can control the acceleration difference between the occupant and the wheelchair within a safe range by controlling the braking frequency and the duration of each braking. Since the speed of the occupant is transmitted by the wheelchair, the speed of the occupant and the wheelchair is the same when braking. Therefore, controlling the difference in acceleration can control the relative speed of the occupant and the wheelchair, preventing the occupant from flying out of the wheelchair. However, this method takes too long to decelerate, especially when the wheelchair is moving at a high speed. Since the occupant of the wheelchair will fly forward at the speed of braking due to inertia when the wheelchair brakes, the risk of the occupant flying out is greater when the speed is high, and the risk of the user flying out is smaller when the wheelchair is moving at a low speed. Therefore, in order to ensure the deceleration efficiency, a segmented deceleration method is adopted. When the speed is faster, intermittent deceleration is adopted to reduce the difference between the acceleration of the wheelchair and the acceleration of the passenger. When the speed is reduced to a certain threshold (the threshold is the speed at which the user will not fly out of the wheelchair. According to the size of the static friction between different users and the wheelchair seat cushion, the threshold is adjustable for users of different weights.), since the user will not be at risk of falling out of the wheelchair if the wheelchair is braked quickly at this time, the rapid braking method can be controlled at this time to save braking time.

[0043] According to a preferred embodiment, the seat cushion, backrest and armrest of the seat part are combined with each other at an angle less than 90 degrees to lower the center of gravity of the occupant when the occupant sits in the wheelchair, and the armrest can surround the occupant to protect the occupant from flying out of the wheelchair due to inertia when braking. That is, the seat cushion and the backrest are connected to each other and form an angle slightly less than 90 degrees; preferably, the seat cushion is set to have a certain angle with the horizontal plane, and the end of the seat cushion close to the forward direction of the wheelchair is set to be higher than the end of the seat cushion away from the forward direction. The user's center of gravity can be lowered when the user's buttocks touch the end of the seat cushion away from the forward direction, and when the user flies forward relative to the wheelchair due to inertia, the friction between the seat cushion and the occupant can be increased to reduce the risk of the occupant flying out of the wheelchair. Preferably, the armrests include at least a first armrest and a second armrest located on the left and right sides of the passenger when the passenger sits in the wheelchair. The first armrest and the second armrest are arranged on both sides of the seat cushion, and are arranged to be inclined toward the user with one end away from the ground, so that when the user flies out of the wheelchair due to inertia, the armrests can contact the user's waist and abdomen, increase the contact area between the user and the wheelchair, and provide the user with a certain resistance to prevent the passenger from flying out.

[0044] The above-mentioned operation modes of moving forward, backward, turning left and right, and braking are consistent with people's operating habits, and are simple to operate. They can flexibly adjust and control the direction of travel without producing a sense of discontinuity, thereby improving riding comfort. In addition, the steering control device of this embodiment has the advantages of low cost, easy implementation, and easy maintenance. In this way, only two variables v1 and v2 need to be adjusted to control the direction of travel of the wheelchair and the corresponding travel speed. The user can operate easily, and the electronic control system can also be significantly simplified.

[0045] Preferably, the operating unit includes a first operating unit for controlling forward, backward, braking and traveling direction and a second operating unit for controlling traveling speed. The second operating unit can be set to operate in a speed interval.

[0046] The research on the electric wheelchair drive control system, especially the differential steering system, is helpful to improve the electronic and intelligent level of the product. There are two main directions in the research of the differential steering technology of the electric wheelchair drive control system in the prior art. One is to realize it by developing a motor with a special structure, but this method has the disadvantages of complex structure, high development cost and poor versatility; the other is to use a dual controller to realize it through relatively independent control variables and control models, but there are problems such as low control accuracy, difficulty in eliminating control blind spots, large controller volume and complex structure. This embodiment uses independent dual motors to drive the straight-running wheels as rear wheels and driving wheels respectively, and the Mecanum wheels as front wheels and driven wheels, which cooperate with the driving wheels of the straight-running wheels. Different from the differential steering control system of the prior art that is all straight-running wheels, it only needs to regulate the speed and speed difference of the first motor and the second motor to drive the first rear wheel 103 and the second rear wheel 104 respectively, so as to realize the adjustment of the travel direction and lateral speed of the wheelchair. There are few control variables, and the control accuracy can also meet the general needs of wheelchairs for people with mild disabilities. The structure is simple and it is easy to be generally applicable to people with mild disabilities.

[0047] Preferably, the radius of the first front wheel 101 and the second front wheel 102 are both r1, and the radius of the first rear wheel 103 and the second rear wheel 104 are both r2, wherein r1≤r2. Preferably, the distance between the first front wheel 101 and the second front wheel 102 is d1, and the distance between the first rear wheel 103 and the second rear wheel 104 is d2, wherein d1≤d2. With this arrangement, the first front wheel 101 and the second front wheel 102 have a smaller radius than the first rear wheel 103 and the second rear wheel 104, and the wheelchair can have higher stability during movement, especially when there are obstacles on the ground. By making the distance between the first front wheel 101 and the second front wheel 102 smaller than the distance between the first rear wheel 103 and the second rear wheel 104, on the one hand, the wheelchair is more stable during travel, and on the other hand, the accuracy of differential steering control is higher.

[0048] Preferably, the Mecanum wheel is composed of a hub and a roller. The hub constitutes the support of the wheel body, and the roller is installed on the hub in a manner that its rotating shaft is at a 45-degree angle to the hub shaft. Preferably, the surface of the roller is formed as a non-smooth surface. Preferably, the surface of the roller forms a plurality of closely arranged protrusions made of elastic material. Through this arrangement, on the one hand, it can provide shock absorption and buffering for the wheelchair, on the second hand, it can prevent the uneven ground from affecting the direction and speed of the wheelchair, on the third hand, it can prevent obstacles of smaller size on the ground from getting stuck in the gap between the rollers and hindering the normal movement of the wheelchair, and on the fourth hand, when the wheelchair is moving on the ground, the ground contacted by the left and right wheels may have different friction coefficients, resulting in deviations in the differential control of the wheelchair. This arrangement can effectively reduce the influence of the difference in the ground friction coefficient on the differential control of the wheelchair, making the direction and speed of the wheelchair more accurate. Preferably, the densely arranged protrusions made of elastic material on the surface of the roller are formed into roller sleeves that can be detachably connected to the roller. In this way, when the roller sleeve is worn and deformed after use, affecting the movement of the wheelchair, the roller sleeve can be replaced quickly and easily without replacing the entire Mecanum wheel, thus reducing the cost of use.

[0049] According to a preferred embodiment, the protrusion on the roller sleeve includes at least a first friction point and a second friction point, the first friction point and the second friction point are at different heights, the first friction point is arranged in a manner to buffer when encountering small particle obstacles to form a plurality of buffer spaces, wherein the second friction point is arranged in the buffer space in a manner to prevent particles from getting stuck in the buffer space. The advantages of such a setting are: the first friction point and the second friction point can increase the friction coefficient with the ground, and the buffer space formed by the first friction point can accommodate a part of obstacles with smaller particle sizes, thereby avoiding the influence of such obstacles on the travel of the steering wheel; and the influence of larger obstacles on the travel direction will also be reduced due to the existence of the buffer space. The setting of the second friction point allows larger obstacles entering the buffer space to be supported by the second friction point, and there are also gaps between the second friction points. Through such irregular gap setting, the point pressure on the irregular obstacles in the buffer space can be reduced, so that the irregular obstacles will not get stuck in the buffer space.

[0050] According to a preferred embodiment, the first front wheel 101 and the second front wheel 102 are provided with a non-flat undulating first contact surface for contacting the ground in a manner that can reduce the local pressure when contacting the rugged ground. Preferably, the first rear wheel 103 and the second rear wheel 104 are also provided with a first contact surface. Preferably, the first contact surface includes a first concave portion 105 and a first convex portion 106 surrounding the outer periphery of the first concave portion 105, wherein the curvature of the first concave portion 105 is greater than the curvature of the first convex portion 106. Preferably, a non-sudden curved surface with a hyperbolic curvature formed by a smooth curve is formed between the first convex portion 106 and the first concave portion 105. This allows the adhesion between the stone particles and the roller sleeve to undergo a nonlinear dynamic change when touching the uneven ground or encountering obstacles such as stones on the road surface, so that during the rotation of the wheel, the contact force between the stone and the wheel will not undergo a sudden change, and the stone is not easy to sink into the roller sleeve and get stuck. Such a setting can, on the one hand, increase the friction between the first front wheel 101 and the second front wheel 102 and the ground, thereby increasing the stability of the transfer device during its movement. On the other hand, when the first front wheel 101 and the second front wheel 102 move on the rough ground, the first convex portion 106 and the first concave portion 105 form a shape complementary to the rough ground, which can reduce the occurrence of point contact scenes during the movement of the roller, and ensure that most of the contact between the roller and the ground is line contact during the bumpy process, and in the case of line contact, the first convex portion 106 and the first concave portion 105 can form more structural contact with the rough ground to ensure that the roller can have sufficient friction contact with the ground, so that through the push of the first rear wheel 103 and the second rear wheel 104, the roller can still generate rolling friction with the ground to push the roller to move in the direction to be turned. In this case, the roller will not produce a movement different from the direction to be turned due to the short-term point contact with the ground, which will hinder the turning of the transfer device, and can protect the transfer device from being stuck when turning on the uneven ground. In addition, the setting of the first contact surface with hyperbolic curvature can reduce the probability of adhesion of adhesive substances. Adhesive substances adhere to the surface of the steering wheel and hinder the rotation of the steering wheel. Especially for a Mecanum wheel with multiple sub-wheels, there are gaps between adjacent sub-wheels. When a sticky substance adheres to the surface of a sub-wheel, the adhesive substance will enter between adjacent sub-wheels as the sub-wheel rotates, increasing the rotation resistance of the adjacent sub-wheels, or even directly getting stuck and difficult to rotate, affecting the use of the Mecanum wheel. The setting of the first contact surface can prevent substances from adhering to the sub-wheels, so even when walking on a clay ground on a rainy day, it can prevent clay from adhering to the steering wheel, so that the transfer device can be used in more scenarios.

[0051] Example 2

[0052] A second aspect of the present invention provides a wheelchair, comprising at least a first front wheel 101 and a second front wheel 102, which are coaxial with each other and a first rear wheel 103 and a second rear wheel 104, which are coaxial with each other and are arranged along the body direction of the wheelchair. The wheelchair changes the direction of travel of the wheelchair by the speed difference between the first rear wheel 103 and the second rear wheel 104.

[0053] Preferably, the wheelchair adjusts the lateral speed of the wheelchair by the speed difference between the first rear wheel 103 and the second rear wheel 104. Preferably, the first front wheel 101 and the second front wheel 102 are Mecanum wheels. The first rear wheel 103 and the second rear wheel 104 are straight-moving wheels. The first front wheel 101 and the second front wheel 102 are driven wheels. The first rear wheel 103 and the second rear wheel 104 are driving wheels.

[0054] In this embodiment, the first rear wheel 103 and the second rear wheel 104 are driving wheels, and the first front wheel 101 and the second front wheel 102 have no source power and are driven wheels. The rear wheels are driven, the differential steering is used, and the front wheels cooperate to provide speeds in all directions. The main body of the Mecanum wheel does not rotate, but can provide kinetic energy for the vehicle body to move in all directions.

[0055] The first rear wheel 103 and the second rear wheel 104 are controlled by their own independent motors. When the left and right speeds are different, the left and right rear wheels rotate differentially, which will cause the whole machine to have a turning trend. The main axis of the front wheel Mecanum wheel does not need to be changed relative to the direction of the machine body, and it can cooperate with the rotation of the wheelchair to provide the speed in the required direction. The advantage of the front wheel Mecanum wheel is that it can avoid the two wheel axles turning and forming an angle with each other on bumpy roads like traditional wheelchair universal wheels, making the wheelchair unable to move or even dangerous.

[0056] Preferably, the first motor and the second motor, and the corresponding first rear wheel 103 and second rear wheel 104 are controlled by a hand joystick, and the change of the electrical signal obtained by the joystick is converted into a mechanical change of the motor rotation, thereby controlling the movement of the wheelchair. The direction of the joystick represents the direction of travel of the vehicle, the amplitude of the joystick controls the speed of travel, and releasing the joystick to return to the center controls the brake. Through hand control, actions such as moving forward, turning, reversing, braking, and rotating in place can be achieved.

[0057] The Mecanum wheels used in this embodiment can effectively improve its obstacle-crossing ability. Whether in the process of moving forward or turning, the rear wheel only needs a speed along the direction of the wheelchair body, and does not need a speed perpendicular to the wheelchair, thereby avoiding unnecessary burden and danger. The radius of the rear wheel is larger than the radius of the front wheel, which improves the braking performance and the stability of the wheelchair when it is stationary.

[0058] Example 3

[0059] The third aspect of the present invention discloses an anti-drift wheelchair, which can correct the deviation in time when the wheelchair is traveling due to uneven ground, so as to reduce the risk of rollover during the travel or braking of the wheelchair and ensure the controllability of the wheelchair's route. Since Mecanum wheels have high requirements for the flatness of the ground, route correction is particularly important during the movement.

[0060] Preferably, inertial measurement devices are respectively arranged in the left and right directions perpendicular to the forward direction of the wheelchair, and the inertial measurement devices are arranged to detect the magnitude of acceleration of the wheelchair in the left and right directions.

[0061] The actuation unit of the wheelchair control unit controls the wheelchair to correct the deviation in the following control method:

[0062] Generate the ideal acceleration value in the ideal left and right directions at this time according to the current control instruction;

[0063] Compare the actual acceleration value with the ideal acceleration value.

[0064] When the actual acceleration value is greater than the ideal acceleration value, the direction of the acceleration difference is determined, and the deviation direction of the vehicle route is determined;

[0065] The control motor of the wheel on the side of the deviation direction increases the speed of the wheel, or,

[0066] The control motor controlling the wheel on the side opposite to the deviation direction reduces the speed of the wheel.

[0067] For example, when the instruction controls the wheelchair to move forward, the ideal acceleration values ​​of the wheelchair in the left and right directions perpendicular to the forward direction are both zero. When the actual acceleration value on the left side is greater than zero, the vehicle route is judged to be deviating to the left, and the speed of the left wheel is increased or the speed of the right wheel is reduced to correct the vehicle route.

[0068] Preferably, the acceleration is detected in real time with a first detection period T1, the size of the first detection period T1 is determined according to the actual speed of the wheelchair, and when the actual speed of the wheelchair is greater than the first threshold, the first detection period T1 is shortened.

[0069] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention description and its drawings are illustrative and do not constitute a limitation of the claims. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A wheelchair suitable for people with mild disabilities, comprising at least a support part for supporting the entire wheelchair, a seat part capable of directly contacting the user's body and supporting the user's body parts, a moving part for realizing the movement and stop of the wheelchair, and a control part for realizing the start, stop and steering of the wheelchair, wherein the moving part comprises a first front wheel (101) and a second front wheel (102) coaxial with each other, and a first rear wheel (103) and a second rear wheel (104) coaxial with each other, and a braking device, It is characterized in that The braking device of the moving part controls the wheelchair to decelerate in the following control method to avoid the wheelchair from stopping suddenly: When a braking command is received, the moving speed of the wheelchair is detected; When the moving speed of the wheelchair is greater than the first threshold, the control performs intermittent braking at a set braking frequency; wherein the braking frequency and the duration of each braking are determined by the acceleration difference between the occupant and the wheelchair within the second detection period T, and when the acceleration of the wheelchair is greater than the acceleration of the occupant, the duration of each braking is shortened; When the moving speed of the wheelchair is less than a first threshold, the braking is controlled to continue, and the second detection period T is at most 1 / 2 of the braking period, and the first threshold is a speed at which the user will not fly out of the wheelchair based on the moving speed; The first front wheel (101) and the second front wheel (102) are Mecanum wheels, and the first front wheel (101) and the second front wheel (102) are provided with a non-flat undulating first contact surface for contacting the ground in a manner capable of reducing local pressure when contacting a rough ground; The first contact surface comprises a first concave portion (105) and a first convex portion (106) surrounding the outer periphery of the first concave portion (105), wherein the curvature of the first concave portion (105) is greater than the curvature of the first convex portion (106), and a non-abrupt curved surface with a double curvature formed by a smooth curve is formed between the first convex portion (106) and the first concave portion (105); The first rear wheel (103) and the second rear wheel (104) are straight-moving wheels, wherein the distance between the first front wheel (101) and the second front wheel (102) is smaller than the distance between the first rear wheel (103) and the second rear wheel (104).

2. The wheelchair according to claim 1, characterized in that: The first front wheel (101) and the second front wheel (102) are driven wheels; The first rear wheel (103) and the second rear wheel (104) are driving wheels.

3. The wheelchair according to claim 1 or 2, characterized in that: The first rear wheel (103) and the second rear wheel (104) are respectively controlled by a first motor and a second motor that are independent of each other.

4. The wheelchair according to claim 1, characterized in that: During the moving process, the speed of the first rear wheel (103) is v1, and the speed of the second rear wheel (104) is v2. When v1=v2, the wheelchair moves forward or backward along the direction of the vehicle body.

5. The wheelchair according to claim 4, characterized in that: When v1<v2, the wheelchair moves toward one side of the first rear wheel (103); When v1>v2, the wheelchair moves toward one side of the second rear wheel (104).

6. The wheelchair according to claim 5, characterized in that: The greater the difference between v1 and v2, the greater the speed at which the wheelchair moves toward the first rear wheel (103) or the second rear wheel (104); The smaller the difference between v1 and v2, the smaller the speed at which the wheelchair moves toward the first rear wheel (103) or the second rear wheel (104).

7. The wheelchair according to claim 6, characterized in that: The radii of the first front wheel (101) and the second front wheel (102) are both r1, and the radii of the first rear wheel (103) and the second rear wheel (104) are both r2, wherein r1≤r2.

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