A wheelchair structure capable of going up and down stairs and its intelligent control method

Abstract

The present invention proposes an intelligent wheelchair and a control method for getting on and off the curb. The intelligent wheelchair includes the structure of the intelligent wheelchair and a measurement and control device. The intelligent wheelchair structure of the present invention is composed of a wheelchair body, a linear motor, a laser radar, a driving wheel, an auxiliary support wheel, an inclination sensor, etc. The method of the present invention is: by using a laser radar to measure the terrain around the wheelchair and the steps or similar obstacles to be passed, and by taking turns to accurately control the linear motor to raise and lower the body and driving wheel of the wheelchair so that it is suitable for the current terrain characteristics, thereby controlling the wheelchair to pass the steps smoothly. The role of the inclination sensor is to monitor the safety of the wheelchair in the above process and play a protective role. The present invention can assist the wheelchair to safely get on and off the curb, has a strong terrain passing ability, is an intelligent control device and method, and can meet the safety and comfort requirements of wheelchair occupants in the process of going up and down stairs when traveling in a wide area.

Description

Technical Field

[0001] The present invention relates to the field of intelligent device control and perception, and in particular to a wheelchair structure capable of ascending and descending stairs and an intelligent control method thereof. Background Art

[0002] The problem of population aging has become a global trend. At the same time, there are still a considerable number of disabled people due to diseases, disasters and other reasons, which has led to a rapid increase in the demand for wheelchairs. Due to the improvement of living standards, wide-area travel has become a basic need for the elderly and disabled. In order to realize the functions of wheelchairs such as climbing steps and stairs, scientific and technological workers and inventors have done a lot of work. For climbing stairs alone, nearly 200 patents have been applied for in China. Due to the lack of cost-effectiveness, coupled with the promotion of small high-rise elevators and the widespread installation of wheelchair ramps in public places, the demand for wheelchairs to climb stairs for the elderly and disabled has been greatly reduced.

[0003] However, in many cases, it is still necessary for the wheelchair to be able to smoothly go up and down the steps like curbs. At present, there are two main ways to solve this type of problem: one is to use a tracked wheelchair, such as the patent "An all-terrain walking wheelchair" (202310708467.0) proposes a tracked all-terrain walking wheelchair, which improves the terrain passability of the wheelchair. The second is to use high-power and large-diameter walking wheels to improve the passability of the wheelchair. Although these two types of wheelchairs can realize the function of going up and down stairs, there are still the following problems: First, the wheelchair will have a serious backward tilt when going up the stairs, which not only puts great psychological pressure on the occupants, but also there is indeed a possibility of rollover that the occupants cannot find and control; second, when going down the stairs, there will be a serious feeling of falling. Both types of problems will not only make the wheelchair occupants feel uncomfortable, but also damage the wheelchair structure. In response to this problem, the present invention proposes an effective and low-cost intelligent control solution. Summary of the invention

[0004] To solve the above problems, the present invention discloses a wheelchair structure that can go up and down stairs and an intelligent control method thereof: the intelligent wheelchair state perception and control system designed by the method can identify the curb and obtain the curb distance and height information, and then use the auxiliary support frame to achieve the purpose of going up and down the curb, which can effectively improve the accuracy and safety of the wheelchair going down the curb and has a strong terrain passing ability.

[0005] A wheelchair structure that can go up and down stairs, comprises a wheelchair body, walking wheels, and auxiliary support wheels, wherein the wheelchair body is composed of a seat plate, a foot pedal, and a backrest plate, and is characterized in that; it also includes linear motor one, linear motor two, linear motor three, linear motor four, linear motor five, a laser radar, and an inclination sensor; wherein linear motor one, linear motor two, linear motor three and linear motor four are exactly the same in structure, and the centers of the four linear motors are arranged in a rectangle, and the size of the rectangle is adapted to the seat plate; linear motor five is connected and adapted to the foot pedal; the inclination sensor is fixedly connected to the seat plate to measure the inclination angle of the seat plate relative to the horizontal plane; wherein the laser radar includes a left front radar and a right front radar.

[0006] Furthermore, the linear motor five comprises an electric cylinder five fixedly connected to the foot pedal and a telescopic rod five matched therewith. The movement direction of the telescopic rod five is parallel to the foot pedal, and the telescopic amount is recorded as L202.

[0007] Furthermore, the linear motor 1 includes an electric cylinder 1 fixedly connected to the seat plate and a telescopic rod 1 matched thereto, the movement direction of the telescopic rod 1 is perpendicular to the seat plate, and the telescopic amount is recorded as L212; the linear motor 2 includes an electric cylinder 2 fixedly connected to the seat plate and a telescopic rod 2 matched thereto, the movement direction of the telescopic rod 2 is perpendicular to the seat plate, and the telescopic amount is recorded as L222; the linear motor 3 includes an electric cylinder 3 fixedly connected to the seat plate and a telescopic rod 3 matched thereto, the movement direction of the telescopic rod 3 is perpendicular to the seat plate, and the telescopic amount is recorded as L232; the linear motor 4 includes an electric cylinder 4 fixedly connected to the seat plate and a telescopic rod 4 matched thereto, the movement direction of the telescopic rod 4 is perpendicular to the seat plate, and the telescopic amount is recorded as L242; linear array laser radars are fixedly installed on the electric cylinder 1 and the electric cylinder 2, respectively, and the corresponding numbers are left front radar and right front radar, respectively.

[0008] Furthermore, the telescopic rod includes a telescopic part and a mounting part; the telescopic part is a component that matches the electric cylinder and forms a linear motion; the mounting part is used to install the support wheel; the support wheel rotates freely around the mounting part, the center of the support wheel is at a height of h5 from the ground, and the height difference between the foot pedal and the ground is h12.

[0009] Furthermore, telescopic rod 1, telescopic rod 1, telescopic rod 1, and telescopic rod 1 are respectively equipped with an electrically driven left front drive wheel, right front drive wheel, left rear drive wheel, and right rear drive wheel; the radius of the four drive wheels is R; when the drive wheels are not powered, they can rotate freely around their own axes; after power is supplied, the speed and angle of the drive wheels can be controlled.

[0010] Furthermore, the fixing position of the inclination sensor is not limited to directly above the seat board or below the seat board or other positions.

[0011] An intelligent control method for a wheelchair that can go up and down steps. The control method for the wheelchair to go up steps includes a left front lidar and a right front lidar. The distance between the coordinate origins of the two is L14. Let: the distance from the left front lidar to the step measured by the wheelchair be d31, and the distance from the right front lidar to the step measured by the wheelchair be d32; it is set that the height of the step measured by both the left front lidar and the right front lidar is h; according to the above measurement values, the following describes the method of stably controlling the wheelchair to go up steps:

[0012] The first step: Normal walking on a flat road; when walking on a flat road, the linear motor of the wheelchair is in a retracted state, and the measurement values of the lidar meet the criteria for a flat road;

[0013] The second step: After discovering the step, if one lidar detects a step higher than the road surface while the other does not, it means that the forward direction of the wheelchair is not perpendicular to the step; the wheelchair decelerates and adjusts its traveling direction to ensure that both the left front lidar and the right front lidar detect the step, and the measured distances d31 and d32 are the same, and at the same time ensure that the distance is greater than L15 to prevent the footrest from hitting the step; the distance from the footrest 11 to the centers of the left front drive wheel 41 and the right front drive wheel 42 is L15

[0014] The third step: Lift the body; at an appropriate position where d31 = d and d > L15, such as: when d - L15 = 10 cm, the telescopic rod one of the linear motor one, the telescopic rod two of the linear motor two, the telescopic rod three of the linear motor three, and the telescopic rod four of the linear motor four extend simultaneously, and the extension amount is the step height h, so that the footrest is higher than the step; the wheelchair continues to move forward slowly; at this time, the vertical height of the left front lidar and the right front lidar relative to the ground is: L0 = hs + h, where hs is the vertical height of the left front lidar and the right front lidar relative to the ground in the initial state;

[0015] The fourth step: Directly go up the step; when the measured step height h < R / 3, the wheelchair can continue to move forward and directly go up the step; and jump to the eighth step;

[0016] The fifth step: The auxiliary support wheel extends; when d ≤ L54, it indicates that the auxiliary support wheel is already above the step, then control the telescopic rod five of the support linear motor five to extend, and the extension amount is h / cosα, where α is the angle between the telescopic rod five and the vertical direction; make the auxiliary support wheel contact the step, and it is also allowed that the auxiliary support wheel leaves the step surface a little, generally the distance is less than 10 mm; the wheelchair continues to move forward;

[0017] Step 6: Lift the left front drive wheel and the right front drive wheel; control the telescopic rod 1 of linear motor 1 and the telescopic rod 2 of linear motor 2 to retract, and the retraction amount is the step height h; at this time, the left front drive wheel and the right front drive wheel are lifted off the ground; the wheelchair实质上relies on the left rear drive wheel and the right rear drive wheel to continue moving forward; at this time, the vertical height of the left front lidar and the right front lidar relative to the ground is: L0 = hs + h;

[0018] Step 7: The left front drive wheel and the right front drive wheel climb onto the step; the wheelchair moves forward intermittently and slowly. When L0 = hs, it indicates that the left front drive wheel and the right front drive wheel just touch the road surface on the step; Step 8: The left rear drive wheel and the right rear drive wheel start to retract; when the measured values of the left front lidar and the right front lidar are d31 = d32 = L13 - R, it indicates that the rear drive wheels are very close to the step; assume the forward speed of the wheelchair is v1, and the retraction speeds of the telescopic rod 3 of linear motor 3 and the telescopic rod 4 of linear motor 4 242 are v2, and the retraction amount is L234:

[0019] When L234 + R - h < R / 2, V2 = 2V1

[0020] When R / 2 < L234 + R - h < 1.7R, V2 = V1

[0021] When L234 + R - h > 1.7R, V2 = V1 / 2

[0022] Step 9: Reset the wheelchair; when the measured values d31 = d32 of the left front lidar and the right front lidar are greater than L13, it indicates that the wheelchair has climbed onto the step; linear motor 1, linear motor 2, linear motor 3, linear motor 4, and linear motor 5 retract all the telescopic rods to restore the wheelchair to its initial state; return to Step 1.

[0023] A further improvement of the present invention lies in: the method for the wheelchair to go down the step specifically includes:

[0024] Step 1: Walk normally on a flat road surface; when walking on a flat road surface, the linear motors of the wheelchair are in the retracted state, and the measured values of the lidar meet the criteria for a flat road surface;

[0025] Step 2: Detect the step and adjust the walking posture of the wheelchair; assume that one lidar has detected a step lower than the road surface in the forward direction, while the other has not detected it, indicating that the forward direction of the wheelchair is not perpendicular to the step; then the wheelchair decelerates and approaches the step until both lidars can detect the step; adjust the direction of the wheelchair so that the measured values d31 = d32 of the left front lidar 31 and the right front lidar 32, and d31 > R;

[0026] Step 3: Go down the step directly; when the measured step height h < 0.3R, the wheelchair moves forward directly and makes all the drive wheels go down the step, entering Step 11.

[0027] Step 4: The auxiliary support wheel 5 extends; the wheelchair moves forward intermittently and slowly. When d31 = R, it indicates that the front walking wheel is approaching the step. Then, control the telescopic rod 202 of the support linear motor five 20 to extend, and the extension amount is h / cosα, where α is the angle between the telescopic rod 202 and the vertical direction, so that the auxiliary support wheel 5 contacts the road surface under the step. It is also allowed that the auxiliary support wheel 5 leaves the step surface slightly, generally with a distance less than 10 mm; the wheelchair continues to move forward and makes d31 = d32;

[0028] Step 5: The front walking wheel exceeds the step; the wheelchair moves forward intermittently and slowly. When d31 = 0 and L0 = hs + h, it indicates that the center line of the front walking wheel has reached the edge of the step; prepare to lower the front walking wheel;

[0029] Step 6: The front walking wheel starts to lower; assume the forward speed of the wheelchair is v1, and the speeds of the telescopic rod 212 of the linear motor one 21 and the telescopic rod 222 of the linear motor two 22 extending are v2, and the extension amounts L212 = L222 ≈ h - 10. Control the telescopic rod 212 of the linear motor one 21 and the telescopic rod 222 of the linear motor two 22 according to the following rules to make the front walking wheel close to the ground but not land:

[0030] When L212 < 0.3R, V2 = V1 / 2

[0031] When 0.3R < L212 < 0.7R, V2 = V1

[0032] When L212 > 0.7R, V2 = 2V1

[0033] During this process, the wheelchair is driven forward by the left rear drive wheel 43 and the right rear drive wheel 44; after this process, the front walking wheel is only very close to the road surface but has not fully landed. Therefore, it will not affect the movement of the rear wheels during the subsequent process due to the friction between the front wheels and the ground, but it can prevent the wheelchair from tipping over;

[0034] Step 7: Adjust the direction of the wheelchair and lower the front wheel; to keep the wheelchair balanced when the next walking wheel goes down the step, it is necessary to adjust the direction of the wheelchair; control the differential speed of the left rear drive wheel and the right rear drive wheel of the wheelchair to make the wheelchair rotate around the left front drive wheel; and use the left front lidar 31 and the right front lidar 32 to measure the distances d31 and d32 of the step;

[0035] When 0.9R < d31 < 1.1R and 0.9L13 < d32 < 1.1L13 are satisfied, the right front wheel of the wheelchair is equivalent to staying still but will not contact the rear step. Make d32 ≈ L13 to form an angle between the forward direction of the wheelchair and the step The preferred theoretical value of is: In this way, the left rear drive wheel is already at the edge of the step and ready to step down the step;

[0036] Similarly, the wheelchair can also be rotated around the right front drive wheel, and the process is exactly the same as above, so that the right rear wheel is ready to step down the step; Subsequently, control the linear motor one 21 to extend the telescopic rod one 212 and the linear motor two to extend the telescopic rod two 222, and the telescopic amount L212 = L222 = h, so that the front wheels of the wheelchair land and can provide forward power;

[0037] Eighth step: One rear drive wheel exceeds the step and touches the ground; Control the wheelchair to move forward slowly. The left front drive wheel 41 and the right front drive wheel 42 have completely landed and provide the main walking power. One of the two rear drive wheels close to the step is about to exceed the step and is ready to land; The left rear drive wheel 43 is close to the step. When the wheelchair moves forward, the left rear drive wheel 43 will first exceed the step and land. During this process, it is necessary to control the linear motor three 23 to extend the telescopic rod three 232, so as to drive the left rear drive wheel 43 to descend, and record the telescopic amount as L232; Let the forward speed of the wheelchair be v1, and the speed of the linear motor three 23 to extend the telescopic rod three 232 be v2. Control v2 according to the following rules:

[0038] When L232 < 0.3R, V2 = V1 / 2

[0039] When 0.3R < L232 < 0.7R, V2 = V1

[0040] When L232 > 0.7R, V2 = 2V1

[0041] Until the extension amount L232 = h, so that the left rear drive wheel 43 lands;

[0042] Similarly, the right rear drive wheel 44 is close to the step. When the wheelchair moves forward, the right rear drive wheel 44 will first exceed the step. During this process, it is necessary to control the linear motor four 24 to extend the telescopic rod four 242, so as to drive the right rear wheel to descend, and record the telescopic amount as L242; Let the forward speed of the wheelchair be v1, and the speed of the linear motor four 24 to extend the telescopic rod four 242 be v2; Control v2 according to the following rules:

[0043] When L242 < 0.3R, V2 = V1 / 2

[0044] When 0.3R < L242 < 0.7R, V2 = V1

[0045] When L242 > 0.7R, V2 = 2V1

[0046] Until the extension amount L242 = h, so that the right rear drive wheel lands;

[0047] Step 9: The other rear drive wheel approaches the step and is ready to fall and touch the ground. At this time, you need to move the last drive wheel on the step to the vicinity of the step. Continue to control the wheelchair to move forward slowly at the same speed until the last drive wheel approaches the step;

[0048] Step 10: The last rear drive wheel falls and touches the ground; continue to control the wheelchair to move forward slowly until the last drive wheel touches the ground.

[0049] Step 11: The wheelchair returns to the initial state. When all the driving wheels have finished descending the steps, the extended telescopic rods 5 202, 1 212, 222, 3 232 and 4 242 need to be retracted at the same time to make the wheelchair seat fall and return the wheelchair to the initial state.

[0050] Beneficial effects of the present invention:

[0051] The intelligent wheelchair state perception and control system designed by this method can identify the curb, obtain the distance and height information of the curb, and then use the auxiliary support frame to achieve the purpose of getting on and off the curb, which can effectively improve the accuracy and safety of the wheelchair going off the curb and has a strong terrain passing ability; at the same time, compared with the tracked wheelchair, the structure is simpler, making the wheelchair cost lower, while meeting the safety and comfort requirements of the wheelchair going on and off the curb, providing a more convenient travel method for the disabled. In addition, the method proposed by the present invention is related to the structural parameters of the wheelchair, but is not affected by the size of the wheelchair drive wheel. In fact, it also provides a universal design solution, which is conducive to expanding the design ideas of wheelchairs and improving the design level of wheelchairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is the wheelchair structure diagram and the overall sensor installation diagram;

[0053] Figure 2 is a schematic diagram of a telescopic rod;

[0054] Figure 3 This is a projection diagram of the wheelchair structure (left: main view, right: left view);

[0055] Figure 4 This is a schematic diagram of the laser radar road condition measurement principle;

[0056] Figure 5 Schematic diagram of steps discovered by LiDAR;

[0057] Figure 6 Schematic diagram for accurate measurement of step parameters;

[0058] Figure 7 This is a schematic diagram of the measurement of steps below the road surface;

[0059] Figure 8 This is a schematic diagram of backward measurement;

[0060] Fig. 9 Diagram of adjusting posture for wheelchair to find steps;

[0061] Fig.10 A schematic diagram of the walking direction to approach the steps;

[0062] Fig.11 This is a diagram of a wheelchair approaching the steps;

[0063] Fig.12 Schematic diagram of lifting the body for a wheelchair;

[0064] Fig.13 This is a schematic diagram of the support wheel contact step;

[0065] Fig.14 Schematic diagram of the front drive wheels climbing up the steps;

[0066] Fig.15 This is a schematic diagram of the rear drive wheel approaching the step;

[0067] Fig.16 Diagram for wheelchair climbing stairs;

[0068] Fig.17 Schematic diagram for finding steps below the road surface;

[0069] Fig.18 Schematic diagram for adjusting the walking direction of the wheelchair;

[0070] Fig.19 This is a schematic diagram showing the pedal reaching the vicinity of the steps;

[0071] Fig. 20 This is a schematic diagram of the support wheel landing;

[0072] Fig.21 This is a schematic diagram of the front driving wheel reaching the edge of the step;

[0073] Fig. 22 It is a schematic diagram of the front driving wheel being dropped;

[0074] Fig.23 Prepare the step-down diagram for the left rear wheel;

[0075] Fig.24 Schematic diagram of preparing the step down for the right rear wheel;

[0076] Fig.25 This is a schematic diagram of the front drive wheel landing;

[0077] Fig.26 This is a schematic diagram of the left rear wheel reaching the edge of the step;

[0078] Fig. 27This is a schematic diagram of the right rear wheel reaching the edge of the step;

[0079] Fig.28 This is a schematic diagram of the right rear wheel reaching the edge of the step;

[0080] Fig.29 This is a schematic diagram of the left rear wheel reaching the edge of the step;

[0081] Fig.30 This is a schematic diagram of the right rear wheel falling down the step;

[0082] Fig.31 This is a schematic diagram of the left rear wheel falling down the step;

[0083] Fig.32 Diagram of adjusting posture for wheelchair to find steps;

[0084] Fig.33 A schematic diagram of the walking direction to approach the steps;

[0085] Fig.34 This is a diagram of a wheelchair approaching the steps;

[0086] Fig.35 A schematic diagram of lifting the wheelchair body;

[0087] Fig.36 This is a schematic diagram of the support wheel contact step;

[0088] Fig.37 Schematic diagram of the front drive wheels climbing up the steps;

[0089] Fig.38 Angle between wheelchair and steps Schematic diagram;

[0090] Fig.39 Prepare the step-up diagram for the right rear wheel;

[0091] Fig.40 Schematic diagram of the left rear drive wheel climbing up the steps;

[0092] Fig.41 Schematic diagram of the right rear drive wheel climbing up the steps;

[0093] Fig.42 This is a schematic diagram of the right rear wheel approaching the step;

[0094] Fig.43 This is a schematic diagram of the left rear wheel approaching the step;

[0095] Fig.44 This is a schematic diagram of the wheelchair state perception and control process. DETAILED DESCRIPTION

[0096] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0097] Figure 1 Schematic diagram of the structure of the intelligent wheelchair of the present invention. It consists of a wheelchair body, a linear motor, a laser radar, a running wheel, an auxiliary support wheel 5, an inclination sensor 6, etc. The wheelchair body consists of a seat plate 11, a footrest 12, and a backrest plate 13.

[0098] The linear motor of the present invention generally refers to various types of electric telescopic devices that can achieve linear motion, and their telescopic motion is like the motion of a piston cylinder and a piston, such as an electric push rod and a servo electric cylinder. In the present invention, such devices are abstracted as an electric cylinder and a telescopic rod that can perform linear motion relative to the electric cylinder, such as Figure 2 As shown:

[0099] The linear motor 5 20 comprises an electric cylinder 5 201 fixedly connected to the foot pedal 12 and a telescopic rod 5 202 matched therewith. The movement direction of the telescopic rod 5 202 is parallel to the foot pedal 12, and the telescopic amount is recorded as L202.

[0100] The linear motor 21 comprises an electric cylinder 211 fixedly connected to the seat plate 11 and a telescopic rod 212 matched therewith. The movement direction of the telescopic rod 212 is perpendicular to the seat plate, and the telescopic amount is recorded as L212.

[0101] The linear motor 22 includes an electric cylinder 221 fixedly connected to the seat plate 11 and a matching telescopic rod 222. The movement direction of the telescopic rod 222 is perpendicular to the seat plate, and the telescopic amount is recorded as L222.

[0102] The linear motor 3 23 comprises an electric cylinder 3 231 fixedly connected to the seat plate 11 and a telescopic rod 3 232 matched therewith. The movement direction of the telescopic rod 3 232 is perpendicular to the seat plate, and the telescopic amount is recorded as L232.

[0103] The linear motor 24 comprises an electric cylinder 241 fixedly connected to the seat plate 11 and a telescopic rod 242 matched therewith. The movement direction of the telescopic rod 242 is perpendicular to the seat plate, and the telescopic amount is recorded as L242.

[0104] The structures of linear motor 21, linear motor 22, linear motor 23 and linear motor 24 are exactly the same. The centers of the four linear motors are arranged in a rectangular shape, and the size of the rectangle is adapted to the seat plate.

[0105] The structure of the telescopic rod 5 202 is shown in the figure, which includes a telescopic part 2021 and a mounting part 2022. Its main features are: the telescopic part 2021 is a component that matches the electric cylinder and forms a linear motion, and 2021 itself can also rotate freely around its own axis; the mounting part 2022 is used to install the support wheel 5. The support wheel 5 can rotate freely around the mounting part 2022. It has no power and only plays an auxiliary supporting role. It can be seen that a universal wheel is formed by the support wheel and the telescopic rod 2021, and its function is equivalent to a universal caster. In fact, the support wheel 5 itself can also be replaced with a universal caster. Therefore, when the support wheel 5 contacts the ground and plays a supporting role, it does not affect the control of the walking direction of the wheelchair by other walking wheels. Figure 3 As shown, the height of the center of the support wheel 5 from the ground is h5, and the height difference between the foot pedal and the ground is h12.

[0106] The structures of telescopic rod 1 212, telescopic rod 2 222, telescopic rod 3 232, and telescopic rod 4 242 are similar to the structure of telescopic rod 5 202, and are respectively equipped with electrically driven left front driving wheel 41, right front driving wheel 42, left rear driving wheel 43, and right rear driving wheel 44. The radius of the four driving wheels is R. When the driving wheel is not powered, it can rotate freely around its own axis, which is equivalent to a follower wheel; after power is powered, the speed and angle of the driving wheel can be controlled. Therefore, when the left front driving wheel 41 and the right front driving wheel 42 are powered at the same time, the power for the wheelchair to move straight can be generated to drive the wheelchair to move; when the left rear driving wheel 43 and the right rear driving wheel 44 are powered at the same time, the power for the wheelchair to move straight can also be generated to drive the wheelchair to move; when the four driving wheels 41, 42, 43, and 44 are powered at the same time, a stronger power can be generated to complete the power required for climbing a slope, crossing obstacles, etc.; when the driving wheels on different sides move at different speeds, the wheelchair can be made to turn while walking.

[0107] The inclination sensor 6 is fixedly connected to the seat board to measure the inclination angle of the seat board relative to the horizontal plane. In the figure, the inclination sensor 6 is fixedly installed just above the seat board, but is not limited to just above the seat board. It can also be installed below the seat board or other positions. The inclination sensor is a MESM acceleration sensor, which can measure the acceleration of the wheelchair in addition to the inclination angle of the wheelchair seat.

[0108] Figure 1 The middle telescopic rod 5 202, the telescopic rod 1 212, the telescopic rod 2 222, the telescopic rod 3 232, and the telescopic rod 4 242 are all in the extended position. When the wheelchair is moving normally horizontally, all these telescopic rods should be retracted to put the wheelchair in the initial state;

[0109] like Figure 3As shown in the figure, they are the front view and the left view of the initial state of the wheelchair, respectively. In this initial state, the height of the seat board 11 of the wheelchair from the ground is the lowest, and the center of gravity of the combination of the occupant and the wheelchair is also the lowest. This is the default state of the wheelchair and the normal walking state. At the same time, the distance between the footrest and the ground is also the lowest, which is convenient for the occupant to leave the wheelchair.

[0110] See also Figure 1 Linear array laser radars are fixedly installed on the electric cylinder 1 211 and the electric cylinder 2 221, and the corresponding numbers are left front laser radar 31 and right front laser radar 32. Considering that all four electric cylinders are fixedly connected to the seat plate 11, the two laser radars 31 and 32 are also fixedly connected to the wheelchair body. The installation position includes but is not limited to the position shown in the figure. The function of the laser radar is to measure and identify the road conditions in the direction of the wheelchair.

[0111] Linear array laser radar is a multi-point distance measuring instrument that can control the laser line to deflect at a certain angle in the same plane and measure the distance of each laser line from the target. According to the deflection angle and ranging value, the shape, distance and other information of the target can be measured. Since the deflection angle is known, partial measurement values ​​of the linear array laser radar can also be used intentionally to obtain information about the target.

[0112] like Figure 4 As shown, the laser radar measurement center is directed directly below the wheelchair. To facilitate the explanation of the principle of the present invention, L0 is taken as the plumb laser line, and 7 laser lines in the direction of the wheel forward are selected at equal intervals, which are called forward measurement values. Their ranging values ​​Li are recorded as L0, L1...L6, L7 respectively, and the angle between every two laser lines is Therefore, the deflection angle of the 8th laser line L7 is Obviously, L0 can directly measure the installation height hs of the laser radar, hs=L0.

[0113] At the same time, R0 can also be taken as the plumb laser line, and then 7 laser lines emitted by the laser radar in the direction behind the wheelchair are selected at equal intervals, which are called backward measurement values. The ranging values ​​are R0, R1...R6, R7 respectively, and the angle between each two laser lines is Therefore, the deflection angle of the 8th laser line R7 is Obviously, R0 can directly measure the installation height hs of the laser radar, hs=R0.

[0114] From the above description, it can be seen that L0 and R0 are the same laser line, that is, L0=R0.

[0115] The following combination Figure 4 Explain the principle of road condition measurement based on lidar.

[0116] 1. How to determine whether the wheelchair is moving in a flat road:

[0117] When the road surface is flat, there are:

[0118] Li×cosΦLi=L0=hs and Ri×cosφRi=R0=hs (i=1,2,…7) (1)

[0119] 2. Determine whether there are steps above the ground in the direction of the wheelchair, and measure the step parameters:

[0120] like Figure 5 As shown in the figure, when there is a step in front of the wheelchair, the forward measurement value of the laser line measures the vertical plane of the step in the order of large number first and small number later. The laser line irradiated on the vertical plane of the step satisfies:

[0121] Li×cosΦLi <hs (i=7,6,n) (2)

[0122] d=Li×sinΦLi (i=7, 6, n) (3)

[0123] n is the smallest number of all laser lines irradiated on the vertical plane of the step, and the remaining laser lines satisfy equation 1. d is the distance from the vertical plane of the step to the origin of the laser radar coordinate system.

[0124] As the wheelchair moves forward, the value of d gradually decreases. Figure 5 In this case, n=6, and we have:

[0125] L7×cosΦL7 <hs(hs=L0)

[0126] L6×cosΦL6 <hs(hs=L0)

[0127] L5×cosφL5=L4×cosφL4=L3×cosφL3=L2×cosφL2=L1×cosφL1=hs=L0

[0128] L7×sinΦL7=L6×sinΦL6=d

[0129] Therefore, the criterion for whether there is a step in the direction of the wheelchair's forward movement is: starting from the laser line with a large number, at least one laser line measurement value satisfies Formula 2.

[0130] 3. Determine the measured value of the step parameters in the direction of the wheelchair:

[0131] like Figure 6 As shown in the figure, when there is a step in front of the wheelchair, the laser line measures the horizontal plane of the step above the ground in the order of large number first and small number later. The laser line irradiated on the horizontal plane of the step meets the following requirements:

[0132] Li×cosΦLi <hs (i=7,6,n) (4)

[0133] The laser line shining on the plumb plane of the step can be used to measure the distance d:

[0134] Li×sinΦLi=d,(i=n-1,n-2…m)

[0135] The laser line irradiated on the horizontal surface under the step meets

[0136] Li×cosΦLi=hs,(i=m-1,m-2…0) (5)

[0137] At this time, the step height h can be measured:

[0138] h=L0-L7×cosΦLi (6)

[0139] As an illustrative example, Figure 6 In the present invention, n=6, m=4. In the subsequent control of the wheelchair, the step height h and the distance d need to be known. As can be seen from the above description, each parameter can be measured by multiple laser lines, and its optimal estimated value can be obtained by a certain method, so there is a high measurement accuracy.

[0140] 4. When judging whether there are steps below the ground in the direction of the wheelchair, the measured value of the step parameters:

[0141] like Figure 7 As shown in the figure, when there is a step in front of the wheelchair, the laser line illuminates the ground below the step in the order of large number first and small number later, and the measurement value is:

[0142] Li×cosΦLi>hs (i=7, 6, n) (7)

[0143] Li×cosΦLi=hs=L0,(i=n-1,n-2…1) (8)

[0144] h=L7×cosΦLi-L0 (9)

[0145] d=Ln×sinΦLn-L n-1 ×sinΦL n-1 (10)

[0146] By Example Figure 7 , in the above formulas, n=4.

[0147] 5. Backward measurement of the parameters of the step behind the lidar,

[0148] In the same way, the step parameters behind the laser radar can be obtained using the backward measurement value, such as Figure 8 As shown:

[0149] Ri×cosΦRi <hs (i=7,6,n) (11)

[0150] Ri×cosΦRi <hs (i=n-1,m、n-2...m) (12)

[0151] Ri×cosΦRi=hs (i=m-1,m-2…0) (13)

[0152] d=Ri×sinΦRi (i=n-1,m,n-2...m) (14)

[0153] h=hs-R7×cosΦR7=hs-R6×cosΦR6=……=hs-Rn×cosΦRn (15)

[0154] n is the minimum number of laser lines irradiating the upper surface of the step, and m is the minimum number of laser lines irradiating the vertical surface of the step. As an example, in the above formulas, n = 6, m = 4

[0155] 6. Control method of wheelchair climbing stairs

[0156] According to the above, the device of the present invention has two laser radars 31 and 32, and the distance between the coordinate origins of the two is L14.

[0157] Assume that the distance between the wheelchair and the steps measured by the left front laser radar 31 is d31, and the distance between the wheelchair and the steps measured by the right front laser radar 32 is d32. In real life, the height of the steps in a small range will not vary much, so the height of the steps measured by the two laser radars 31 and 32 is set to h. Based on the above measurement values, the method of the present invention for smoothly controlling the wheelchair to go up the steps is described below:

[0158] Step 1: Walk normally on a level surface.

[0159] When walking on a normal flat road, the linear motors of the wheelchair are in the retracted state, and the measurement values ​​of the lidar meet the criteria for a flat road.

[0160] Step 2: Find the steps and adjust the walking posture of the wheelchair.

[0161] Combination Figure 3 , and refer to Fig. 9 . Fig. 9 The figure shows a top view of a wheelchair moving. Assume that one laser radar has detected a step above the road surface in the direction of travel. The other laser radar has not detected it, indicating that the wheelchair is not moving perpendicular to the step. The wheelchair slows down and continues to approach the step, and adjusts the direction of travel so that both laser radars can detect the step and have the same distance measurement value, even if d31 = d32. Fig.10As shown. At the same time, ensure that d31 is greater than L15 to prevent the footrest of the wheelchair from hitting the steps.

[0162] Step 3: Lift the vehicle body

[0163] As Fig.11 shown, at the appropriate position where d31 = d and d > L15, for example, when d - L15 = 10 cm, the telescopic rods 212, 222, 232, and 242 of the linear motors 21, 22, 23, and 24 extend simultaneously, and the telescopic amount is the step height h. As a result, the seat plate 11, footrest 12, backrest 13, etc. of the wheelchair are all lifted, making the footrest higher than the steps. The wheelchair continues to move forward slowly and makes d31 = d32. At this time, the detection value of the lidar L0 is: L0 = hs + h. As Fig.12 shown.

[0164] Step 4: Directly climb the steps

[0165] When the measured step height h < R / 3, the wheelchair can continue to move forward and directly climb the steps. Then jump to Step 8.

[0166] Step 5: The auxiliary support wheel 5 extends

[0167] Combined with Figure 3 , when d ≤ L54, it indicates that the support wheel 5 is already above the steps. Then control the telescopic rod 202 of the support linear motor 201 to extend, and control its extension amount to be h / cosα, where α is the angle between the telescopic rod 202 and the vertical direction. As Fig.13 shown, make the support wheel 5 contact the steps, and it is also allowed for the support wheel 5 to leave the step surface slightly, generally with a distance less than 10 mm. The wheelchair continues to move forward and makes d31 = d32.

[0168] Step 6: The left front drive wheel 41 and the right front drive wheel 42 are lifted

[0169] As Fig.13 shown, since the auxiliary support wheel 5 has already contacted the road surface on the steps. At this time, control the telescopic rods 212 and 222 of the linear motor one 21 and the linear motor two 22 to retract, and the retraction distance is the step height h. At this time, the left front drive wheel 41 and the right front drive wheel 42 are lifted and leave the ground. The wheelchair实质上 relies on the left rear drive wheel 43 and the right rear drive wheel 44 to continue moving forward and makes d31 = d32. At this time, since the front walking wheels have been at a distance of h from the ground, the detection value of the lidar L0 is: L0 = hs + h.

[0170] Step 7: The left front drive wheel 41 and the right front drive wheel 42 climb onto the steps

[0171] The wheelchair moves forward intermittently at a slow speed. When L0 = hs, it indicates that the left front drive wheel 41 and the right front drive wheel 42 just come into contact with the road surface on the step. Continue to move forward and make d31 = d32, keeping the walking direction perpendicular to the vertical plane of the step.

[0172] Step 8, the left rear drive wheel 43 and the right rear drive wheel 44 start to retract

[0173] Combined with Figure 3 and Fig.15 , when the left front lidar 31 and the right front lidar 32 detect that the distance between the wheelchair and the step is d31 = d32 = L13 - R, it indicates that the rear drive wheels are already very close to the step. The wheelchair continues to move forward slowly, and at the same time, control the linear motor three 23 and the linear motor four 24 to retract the telescopic rods 232 and 242 according to the following rules. Let the forward speed of the wheelchair be v1, the retraction speed of the linear motor three 23 and the linear motor four 24 for the telescopic rods 232 and 242 be v2, and the retraction amount be L234:

[0174] When L234 + R - h < R / 2, V2 = 2V1

[0175] When R / 2 < L234 + R - h < 1.7R, V2 = V1

[0176] When L234 + R - h > 1.7R, V2 = V1 / 2

[0177] Step 9: The wheelchair returns to the starting state

[0178] When the left front lidar 31 and the right front lidar 32 detect that the distance between the wheelchair and the step is d31 = d32 > L13, it indicates that the left front drive wheel 41, the right front drive wheel 42, the left rear drive wheel 43, and the right rear drive wheel 44 of the wheelchair have all climbed onto the step. The linear motor one 21, the linear motor two 22, the linear motor three 23, the linear motor four 24, and the linear motor five 20 continue to retract all the telescopic rods to make the wheelchair return to the starting state. Go back to step 1.

[0179] 7. Method for the wheelchair to go down the step

[0180] Based on the above measurement values, the method for the present invention to stably control the wheelchair to go down the step is described as follows: Step 1: Normal walking on a flat road

[0181] When walking on a normal flat road, the linear motors of the wheelchair are all in the retracted state, and the measurement values of the lidar meet the criteria for a flat road.

[0182] Step 2: Discover the step and adjust the walking posture of the wheelchair

[0183] Such as Fig.17As shown in the figure, it is a top view of the wheelchair when it is moving. Assume that a lidar has detected a step lower than the road surface in the forward direction, while the other one has not detected it, indicating that the forward direction of the wheelchair is not perpendicular to the step. Then the wheelchair moves forward slowly and approaches the step until both lidars can detect the wheelchair step. Adjust the walking direction of the vehicle so that the lidar 31 and 32 have the same distance measurement value, that is, d31 = d32, and d31 > R, as Fig.18 and Fig.19 shown.

[0184] Fig.17 Detect a step lower than the road surface; Fig.18 Adjust the walking direction of the wheelchair; Fig.19 The footrest reaches near the step;

[0185] Step 3: Go down the step directly

[0186] As Fig.19 shown, when the wheelchair moves forward intermittently and slowly, and the measured height h of the step < 0.3R, the wheelchair moves forward directly and makes all the driving wheels go down the step and enter step 11.

[0187] Step 4: The auxiliary support extends

[0188] When the wheelchair moves forward intermittently and slowly and makes d31 = R, it indicates that the front walking wheel has approached the vertical plane of the step. The telescopic rod 202 of the linear motor five of the auxiliary support extends, and the extension amount is controlled to be h / cosα, where α is the angle between the telescopic rod 202 and the vertical direction. As a result, the support wheel 5 touches the road surface under the step, and the support wheel 5 is also allowed to leave the step surface slightly. The wheelchair continues to move forward and makes d31 = d32.

[0189] Step 5: The front walking wheel starts to exceed the step

[0190] When the wheelchair moves forward intermittently and slowly and makes d31 = 0, and L0 = hs + h, it indicates that the center line of the front walking wheel has reached the edge of the step. Then prepare to lower the front walking wheel, as Fig.21 shown.

[0191] Step 6: The front walking wheel starts to fall

[0192] As Fig. 22 shown, let the forward speed of the wheelchair be v1, and the speeds of 212 and 222 be v2. Control the linear motor one 21 and the linear motor two 22 to retract the telescopic rod according to the following rules until the extension amount L212 = L222 ≈ h - 10, so that the front walking wheel approaches the ground but does not land:

[0193] When L212 < 0.3R, V2 = V1 / 2

[0194] When 0.3R < L212 < 0.7R, V2 = V1

[0195] When L212 > 0.7R, V2 = 2V1

[0196] During this process, the wheelchair is substantially driven forward by the left rear drive wheel 43 and the right rear drive wheel 44. After this process ends, the front traveling wheels are only very close to the road surface but have not fully landed yet. Therefore, it will not affect the movement of the rear wheels during the subsequent process due to the frictional force between the front wheels and the ground, but it can prevent the wheelchair from tipping over and rolling over.

[0197] Step 7: Adjust the traveling direction of the wheelchair and lower the front wheels

[0198] To enable the wheelchair to maintain balance when the next traveling wheel descends the step, the traveling direction of the wheelchair needs to be adjusted. As Fig.23 shown, control the differential speed of the left rear wheel and the right rear wheel of the wheelchair to make the wheelchair rotate around the left front wheel. And measure the distances d31 and d32 of the step using the backward measurement values of the left front lidar 31 and the right front lidar 32.

[0199] As Fig.23 shown, when 0.9R < d31 < 1.1R and 0.9L13 < d32 < 1.1L13 are satisfied, during this process, the right front wheel of the wheelchair is equivalent to staying still in place, making 0.9R < d31 < 1.1R, but the right front wheel will not touch the rear step. Make d32 ≈ L13, and as a result, an included angle is formed between the advancing direction of the wheelchair and the step The preferred theoretical value of is: In this way, the left rear wheel has reached the edge of the step and is ready to step down the step.

[0200] By the same token, the wheelchair can also be made to rotate around the right front wheel, and the process is exactly the same as the above. As Fig.24 shown, make the right rear wheel ready to step down the step. The specific process will not be elaborated here.

[0201] Immediately afterwards, control the telescopic rods 212 and 222 so that their telescopic amounts L212 = L222 = h. As a result, the front wheels of the wheelchair fully land and can provide forward power, as Fig.25 shown.

[0202] Step 8: One of the rear drive wheels exceeds the step and touches the ground.

[0203] Control the left front drive wheel 41, the right front drive wheel 42, the left rear drive wheel 43, and the right rear drive wheel 44 of the wheelchair to move forward slowly at the same speed. At this time, the left front drive wheel 41 and the right front drive wheel 42 have fully landed and provide the main traveling power. One of the rear two drive wheels close to the step is about to exceed the step and is ready to land.

[0204] Therefore, in Fig.23In it, the left rear drive wheel 43 is close to the step. When the wheelchair moves forward, the left rear drive wheel 43 will first exceed the step and land, as Fig.26 shown. During this process, it is necessary to control the telescopic rod 232 of the linear motor three 23 to extend, so as to drive the left rear drive wheel 43 to descend, and record the telescopic amount as L232. Suppose the forward speed of the wheelchair is v1, and the speed of the telescopic rod 232 of the linear motor three 23 extending is v2. Control v2 according to the following rules:

[0205] When L232 < 0.3R, V2 = V1 / 2

[0206] When 0.3R < L232 < 0.7R, V2 = V1

[0207] When L232 > 0.7R, V2 = 2V1

[0208] Until the extension amount L232 = h, so that the rear left drive wheel 43 lands.

[0209] Therefore, in Fig.24 it, the right rear drive wheel 44 is close to the step. When the wheelchair moves forward, the right rear drive wheel 44 will first exceed the step, as Fig. 27 shown. During this process, it is necessary to control the linear motor four 24 to make the telescopic rod 242 extend, so as to drive the right rear drive wheel 44 to descend, and record the telescopic amount as L242. Suppose the forward speed of the wheelchair is v1, and the speed of the telescopic rod 242 of the linear motor 24 extending is v2. Control v2 according to the following rules:

[0210] When L242 < 0.3R, V2 = V1 / 2

[0211] When 0.3R < L242 < 0.7R, V2 = V1

[0212] When L242 > 0.7R, V2 = 2V1

[0213] Until the extension amount L242 = h, so that the rear right drive wheel lands.

[0214] Step 9: Another rear drive wheel approaches the step and is ready to fall and touch the ground

[0215] At this time, three drives have landed, and it is necessary to move the last drive wheel on the step near the step. Therefore, continue to control the left front drive wheel 41, right front drive wheel 42, left rear drive wheel 43, and right rear drive wheel 44 of the wheelchair to move forward slowly at the same speed for a short distance until the last drive wheel is close to the vertical surface of the step.

[0216] For Fig.26 , the termination condition of this step is: the backward measurement value of the right lidar 32 measures d32 = L13, as a result Fig.28 shown

[0217] For Fig. 27 , the termination condition of this step is that the backward measurement value of the left lidar 31 measures d31 = L13, and the result is as Fig.29 shown;

[0218] At this time, the center of the last driving wheel is at the edge of the step.

[0219] Tenth step: The last rear driving wheel descends and touches the ground

[0220] Continue to control the left front driving wheel 41, right front driving wheel 42, left rear driving wheel 43, and right rear driving wheel 44 of the wheelchair to move forward slowly at the same speed until the last driving wheel lands.

[0221] For Fig.28 , the action process is as follows: The right rear driving wheel 44 has approached the step. When the wheelchair moves forward, control the electric cylinder four 241 to extend the telescopic rod four 242, thereby driving the right rear driving wheel 44 to descend. Denote the telescopic amount as L242. Assume the forward speed of the wheelchair is v1, and the speed at which the electric cylinder four 241 extends the telescopic rod four 242 is v2. Control v2 according to the following rules:

[0222] When L242 < 0.3R, V2 = V1 / 2

[0223] When 0.3R < L242 < 0.7R, V2 = V1

[0224] When L242 > 0.7R, V2 = 2V1

[0225] Until the extension amount L242 = h, causing the right rear driving wheel 44 to land, as Fig.30 shown.

[0226] Fig.29 In

[0227] When L232 < 0.3R, V2 = V1 / 2

[0228] When 0.3R < L232 < 0.7R, V2 = V1

[0229] When L232 > 0.7R, V2 = 2V1

[0230] Until the extension amount L232 = h, causing the left rear driving wheel to land, as Fig.31 shown.

[0231] Fig.30 The right rear wheel dropped down the step; Fig.31 The left rear wheel falls off the platform; Step 11: The wheelchair returns to its initial state

[0232] When all the driving wheels have finished going down the steps, it is also necessary to move the extended telescopic rods 5 202 and 1

[0233] The telescopic rod 212, the second telescopic rod 222, the third telescopic rod 232, and the fourth telescopic rod 242 are retracted simultaneously, so that the wheelchair seat falls, and finally the wheelchair is restored to the initial state of walking along a flat road.

[0234] 8. How to use small diameter drive wheels on steps

[0235] When the radius R of the driving wheel is greater than the step height h, Fig.15 As shown, the above method can make the wheelchair go over the step. However, if the radius R of the driving wheel is significantly smaller than the step height h, the method in the sixth embodiment of the present invention may cause the wheelchair to vibrate violently or fail to climb the step at all. Therefore, the present invention provides a method for a wheelchair to smoothly go over the step using a small-diameter driving wheel. Figure 3 illustrate.

[0236] Step 1: Walk normally on a level surface.

[0237] When walking on a normal flat road, the linear motors of the wheelchair are in the retracted state, and the measurement values ​​of the lidar meet the criteria for a flat road.

[0238] Step 2: Find the steps and adjust the walking posture of the wheelchair.

[0239] Combination Figure 3 , and refer to Fig.32 . Fig.32 The figure shows a top view of a wheelchair moving. Assume that one laser radar has detected a step above the road surface in the forward direction. The other laser radar has not detected it, indicating that the wheelchair is not moving perpendicular to the step. The wheelchair slows down and continues to approach the step, and adjusts the direction of travel so that both laser radars can detect the wheelchair step and have the same distance measurement value, even if d31 = d32, as Fig.33 At the same time, ensure that d31 is greater than L15 to ensure that the wheelchair pedal will not hit the steps.

[0240] Step 3: Lift the car body

[0241] like Fig.35As shown, at the appropriate position where d31=d and d>L15, such as: d-L15=10cm, at this time, the footrest of the wheelchair is close to the step. The linear motor 1 21, the linear motor 22, the linear motor 3 23, and the linear motor 4 24 are controlled to extend the corresponding telescopic rods 1 212, 222, 332, and 4 242 at the same time, and the extension amount is the step height h+10mm. As a result, the seat plate 11, footrest 12, backrest 13, etc. of the wheelchair are all lifted up, so that the footrest is higher than the step. The wheelchair continues to move forward slowly, and makes d31=d32. At this time, the detection value of the laser radar L0 is: L0=hs+h. As Fig.35 shown.

[0242] Step 4: Auxiliary support wheel 5 extends

[0243] Combination Figure 3 and Fig.36 When the wheelchair moves forward to d≤L54, it indicates that the support wheel 5 is already above the step, and the telescopic rod 5 202 of the electric cylinder 5 201 is controlled to extend, and its extension amount is controlled to be h / cosα, where α is the angle between the telescopic rod 202 and the vertical direction. Fig.36 As shown, the support wheel 5 is brought into contact with the step.

[0244] Step 6: Lift the left front drive wheel 41 and the right front drive wheel 42

[0245] like Fig.36 As shown, the auxiliary support wheel 5 has already contacted the road surface on the step. At this time, the telescopic rod 1 212 of the linear motor 1 21 and the telescopic rod 2 222 of the linear motor 22 are controlled to retract, and the retracted distance is the step height h+Δh, where 5<Δh<20. In this way, the running wheels 41 and 42 leave the ground. The wheelchair actually continues to move forward by relying on the running wheels 43 and 44, and makes d31=d32. At this time, since the front running wheel is already at a distance h from the ground, the detection value of the laser radar L0 is: L0=hs+h+Δh.

[0246] Step 7: The left front driving wheel 41 and the right front driving wheel 42 climb up the steps

[0247] The wheelchair moves forward intermittently and slowly. When L0=hs, it indicates that the left front driving wheel 41 and the right front driving wheel 42 are just above the step, but not in contact with the road surface. Fig.37 shown.

[0248] Step 8: Adjust the direction of the wheelchair

[0249] In order to make the small-diameter rear left driving wheel 43 or the rear right driving wheel 44 at the back climb up the steps steadily, the wheelchair needs to adjust the walking direction. Fig.37The front drive wheels in the front do not contact the ground, so the differential speed of the left and right rear wheels of the wheelchair can be controlled, and the distances d31 and d32 of the steps are measured using the rearward measurement values of the lidar sensors 31 and 32. When d31 = L13 - R is satisfied, the left rear wheel has approached the vertical surface of the step and is ready to go up the step. At this time, it should also be ensured that d32 = 0 - 50, so that the right front drive wheel 32 is on the road surface side of the step edge on the step and is 0 - 50 away from the vertical surface of the step. This forms an angle between the wheelchair and the step. The preferred theoretical values are: As Fig.38 shown.

[0250] By the same token, it is also possible to have the right rear wheel already at the step edge and ready to go up the step. As Fig.39 shown, get the right rear wheel ready to go down the step. The specific process will not be elaborated here.

[0251] Immediately afterwards, control the telescopic rods 212 and 222 to extend by Δh so that their total telescopic amount is L212 = L222 = h. As a result, the front wheels of the wheelchair fully touch the ground and can provide forward power.

[0252] Step 9: Raise the rear drive wheel closest to the step

[0253] The wheelchair continues to move forward slowly while raising the rear wheel closest to the step. For Fig.38 , the left rear drive wheel 43 is the closest to the step and needs to be raised and climb up the step first. Let the forward speed of the wheelchair be v1, and the speed of the linear motor 231 telescoping back into the telescopic rod 232 be v2. Control v2 according to the following rules:

[0254] When L232 - R > 10 - 40 mm, V2 = max(V2). During this process, due to the symmetrical structure of the wheelchair, the center of gravity of the wheelchair and the occupant is near the diagonal of the centers of the four drive wheels. Since the center of the left rear drive 43 is lower than the upper surface of the step, the wheelchair is in a critical equilibrium state. However, due to the forward power of the drive wheels 41, 42, and 44 at this time, the raised left rear drive wheel 43 is close to the vertical surface of the step and will keep the wheelchair balanced by relying on friction. For safety, V2 should be made to reach the maximum speed of the linear motor as much as possible in order to raise the left rear drive wheel 43 as soon as possible. After this process ends, the center of the left rear drive 43 is 10 - 40 mm higher than the upper surface of the step. After that, control v2 according to the following rules:

[0255] When R - L232 > 0.7R, V2 = 2V1

[0256] When 0.3R < R - L232 < 0.7R, V2 = V1

[0257] When R - L232 < 0.3R, V2 = V1 / 2

[0258] After the above process is completed, the left rear driving wheel is lifted onto the step surface. Fig.40 A similar method can be used to Fig.39 The right rear drive wheel 44 in the embodiment climbs up the steps, as shown in FIG. Fig.41 In this way, there are already three driving wheels on the upper surface of the step that can provide power for the wheelchair to move forward, and the remaining driving wheel is still a certain distance away from the step.

[0259] Step 10: The last drive wheel is close to the step

[0260] The wheelchair continues to move forward slowly, so that the drive wheels under the steps are close to the vertical surface of the steps. Fig.40 When the rearward measurement value of the laser radar 32 is d32=L13-R, it indicates that the right rear drive wheel 44 has approached the vertical surface of the step. Fig.42 As shown; for Fig.41 When the rearward measurement value of the left front laser radar 31 is d31=L13-R, it indicates that the left rear drive wheel 43 has approached the vertical surface of the step. Fig.43 shown.

[0261] Step 11: Raise the last drive wheel

[0262] Raise the last drive wheel as in step 9.

[0263] Step 12: Return the wheelchair to its original state

[0264] When all the driving wheels have finished going down the steps, the extended telescopic rods 202, 212, 222, 232, 242 need to be retracted at the same time to make the wheelchair seat fall down, and finally restore the wheelchair to the initial state of walking along a flat road.

[0265] 9. Safety measurement and control of wheelchairs going up and down stairs

[0266] The present invention provides an independent safety protection mechanism to avoid errors in various wheelchair movements. Fig.44 shown.

[0267] Fig.44 The control electronics of the wheelchair mainly refers to the computer processing unit and its corresponding communication bus required to complete the aforementioned various actions. The mechanical structure of the wheelchair and the corresponding measuring device include the aforementioned wheelchair body 1, linear motor 2, laser radar 3, drive wheel 4, auxiliary support wheel 5, etc. The software part includes the control of the intelligent wheelchair, the use of laser radar 3 for curb recognition, and the use of inclination sensor 6 to measure the balance state of the wheelchair in real time. Fig.44It can be seen that the inclination sensor 6 is independent of the movement of the wheelchair and can measure the balance and vibration of the wheelchair in real time. Therefore, the measurement of the inclination sensor 6 is not affected by the above method and steps, and the balance state of the wheelchair can be obtained at any time in the above method and steps. When it is found that the wheelchair is in a serious imbalance state or violent vibration occurs, other fault handling processes in the intelligent wheelchair are immediately implemented: possible process actions include: terminating the current action, giving an alarm signal, and other actions designed to ensure safety.

[0268] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. An intelligent control method for a wheelchair structure capable of ascending and descending stairs, characterized in that: A wheelchair structure capable of ascending and descending stairs comprises a wheelchair body, walking wheels, and auxiliary support wheels (5), wherein the wheelchair body is composed of a seat plate (11), a footrest (12), and a backrest plate (13), and is characterized in that it also comprises a linear motor 1 (21), a linear motor 2 (22), a linear motor 3 (23), a linear motor 4 (24), a linear motor 5 (20), a laser radar (3), and an inclination sensor (6); wherein the linear motor 1 (21), the linear motor 2 (22), the linear motor 3 (23), and the linear motor 4 (24) are completely identical in structure, the centers of the four linear motors are arranged in a rectangular shape, and the size of the rectangle is adapted to the seat plate; the linear motor 5 (20) is connected and adapted to the footrest (12); the inclination sensor ( 6) is fixedly connected to the seat plate (11) to measure the inclination angle of the seat plate relative to the horizontal plane; wherein the laser radar includes a left front laser radar (31), a right front laser radar (32), a left rear laser radar (33) and a right rear laser radar (34); the linear motor five (20) includes an electric cylinder five (201) fixedly connected to the foot pedal (12) and a telescopic rod five (202) matched therewith, the movement direction of the telescopic rod five (202) is parallel to the foot pedal (12), and the telescopic amount is recorded as L202; the linear motor one (21) includes an electric cylinder one (211) fixedly connected to the seat plate (11) and a telescopic rod one (212) matched therewith, the movement direction of the telescopic rod one (212) is perpendicular to the seat plate (11), and the telescopic amount is L202. The telescopic rod 1 (212) is connected to the left front driving wheel (41); the linear motor 2 (22) comprises an electric cylinder 2 (221) fixedly connected to the seat plate (11) and a telescopic rod 2 (222) matched thereto, the movement direction of the telescopic rod 2 (222) is perpendicular to the seat plate (11), and the telescopic amount is recorded as L222; the telescopic rod 2 (222) is connected to the right front driving wheel (42); the linear motor 3 (23) comprises an electric cylinder 3 (231) fixedly connected to the seat plate (11) and a telescopic rod 3 (232) matched thereto, the movement direction of the telescopic rod 3 (232) is perpendicular to the seat plate, and the telescopic amount is recorded as L232; the telescopic rod 3 (232) is connected to the left rear driving wheel (43); the linear motor 4 (24) comprises an electric cylinder 3 (231) fixedly connected to the seat plate (11) and a telescopic rod 3 (232) matched thereto, the movement direction of the telescopic rod 3 (232) is perpendicular to the seat plate, and the telescopic amount is recorded as L232; the telescopic rod 3 (232) is connected to the left rear driving wheel (43); The electric cylinder 4 (241) fixedly connected to the seat plate (11) is matched with the telescopic rod 4 (242), the movement direction of the telescopic rod 4 (242) is perpendicular to the seat plate, and the telescopic amount is recorded as L242; the telescopic rod 4 (242) is connected to the right rear drive wheel (44); linear array laser radars are fixedly installed on the electric cylinder 1 (211), the electric cylinder 2 (221), the electric cylinder 3 (231) and the electric cylinder 4 (241), respectively, and the corresponding numbers are the left front laser radar (31), the right front laser radar (32); the left rear laser radar (33) and the right rear laser radar (34); the telescopic rod 5 (202) includes a telescopic part (2021) and a mounting part (2022); the telescopic part (2021) is a part matched with the electric cylinder and forms a linear motion;The mounting portion (222) is used to mount the auxiliary support wheel (5); the auxiliary support wheel (5) rotates freely around the mounting portion (222); the height of the center of the auxiliary support wheel (5) from the ground is h5; the height difference between the footrest (12) and the ground is h12; wherein the control method for a wheelchair to go up a step comprises: a left front laser radar (31) and a right front laser radar (32); the distance between the coordinate origins of the two is L14; assuming that the distance from the wheelchair to the step measured by the left front laser radar (31) is d31, and the distance from the wheelchair to the step measured by the right front laser radar (32) is d32; assuming that the heights of the steps measured by the left front laser radar (31) and the right front laser radar (32) are both h; a method for smoothly controlling a wheelchair to go up a step:; Step 1: Normal walking on a flat road; when walking on a flat road, the linear motor of the wheelchair is in the retracted state, and the measured value of the lidar meets the criterion for a flat road; Step 2: After detecting a step, if one lidar detects a step higher than the road surface while the other does not, it means that the forward direction of the wheelchair is not perpendicular to the step; the wheelchair decelerates and adjusts its traveling direction to ensure that both the left front lidar (31) and the right front lidar (32) detect the step, and the measured distances d31 and d32 are the same, while ensuring that the distance is greater than L15 to prevent the footrest from hitting the step; where the distance from the footrest (12) to the centers of the left front drive wheel (41) and the right front drive wheel (42) is L15; Step 3: Lift the body; when d31 = d, and d > L15, d - L15 = 10 cm, the telescopic rod one (212) on the linear motor one (21), the telescopic rod two (222) on the linear motor two (22), the telescopic rod three (232) on the linear motor three (23), and the telescopic rod four (242) of the linear motor four (24) extend simultaneously, and the extension amount is the step height h, so that the footrest is higher than the step; the wheelchair continues to move forward slowly; at this time, the vertical height of the left front lidar (31) and the right front lidar (32) relative to the ground is: L0 = hs + h, where hs is the vertical height of the left front lidar (31) and the right front lidar (32) relative to the ground in the initial state; Step 4: Directly climb the step; when the measured step height h < R / 3, the wheelchair can continue to move forward and directly climb the step; and jump to Step 8; Step 5: The auxiliary support wheel (5) extends; when d ≤ L54, it indicates that the auxiliary support wheel (5) is already above the step, then control the telescopic rod five (202) of the support linear motor five (20) to extend, and the extension amount is h / cosa, where a is the angle between the telescopic rod five (202) and the vertical direction; make the auxiliary support wheel (5) contact the step, and it is also allowed that the auxiliary support wheel (5) leaves the step surface with a distance less than 10 mm; the wheelchair continues to move forward; Step 6: Lift the left front drive wheel (41) and the right front drive wheel (42); control the telescopic rod one (212) of the linear motor one (21) and the telescopic rod two (222) of the linear motor two (22) to retract, and the retraction amount is the step height h; at this time, the left front drive wheel (41) and the right front drive wheel (42) are lifted and leave the ground; the wheelchair实质上relies on the left rear drive wheel (43) and the right rear drive wheel (44) to continue moving forward; at this time, the vertical height of the left front lidar (31) and the right front lidar (32) relative to the ground is: L0 = hs + h; Step 7: The left front drive wheel (41) and the right front drive wheel (42) climb onto the step; the wheelchair continues to move forward slowly, and when L0 = hs, it indicates that the left front drive wheel (41) and the right front drive wheel (42) just touch the road surface on the step; Step 8: The left rear drive wheel (43) and the right rear drive wheel (44) start to retract; when the measured values of the left front lidar (31) and the right front lidar (32) are d31 = d32 = L13 - R, it indicates that the rear drive wheels are very close to the step; let the forward speed of the wheelchair be v1, and the speeds of the retracting telescopic rod three (232) of the linear motor three (23) and the retracting telescopic rod four (242) of the linear motor four (24) be v2, and the retracting amount be L234: When L234 + R - h < R / 2, V2 = 2V1 When R / 2 < L234 + R - h < 1.7R, V2 = V1 When L234 + R - h > 1.7R, V2 = V1 / 2 Step 9: The wheelchair resets; when the measured values of the left front lidar (31) and the right front lidar (32) are d31 = d32 > L13, it indicates that the wheelchair has climbed onto the step; the linear motor one (21), the linear motor two (22), the linear motor three (23), the linear motor four (24), and the linear motor five (20) retract all the telescopic rods to restore the wheelchair to its starting state; go back to Step 1.

2. The intelligent control method for a wheelchair structure capable of ascending and descending stairs according to claim 1, characterized in that: The method for the wheelchair to go down the step specifically includes: Step 1: Normal walking on a flat road; when walking on a flat road, the linear motors of the wheelchair are in the retracted state, and the measured values of the lidar meet the criteria for a flat road; Step 2: Detect the step and adjust the walking posture of the wheelchair; assume that one lidar has detected a step lower than the road surface in the forward direction, while the other has not, indicating that the forward direction of the wheelchair is not perpendicular to the step; then the wheelchair decelerates and approaches the step until both lidars can detect the step; adjust the direction of the wheelchair so that the measured values of the left front lidar (31) and the right front lidar (32) are d31 = d32, and d31 > R; Step 3: Go down the step directly; when the measured height of the step h < 0.3R, the wheelchair moves forward directly and makes all the drive wheels go down the step, entering Step 11; Step 4: The auxiliary support wheel (5) extends; the wheelchair moves forward intermittently and slowly. When d31 = R, it indicates that the front walking wheels are close to the step. Then control the telescopic rod five (202) of the support linear motor five (20) to extend, and the extension amount is h / cosa, where a is the angle between the telescopic rod five (202) and the vertical direction, so that the auxiliary support wheel (5) touches the road surface under the step. It is also allowed that the auxiliary support wheel (5) leaves the step surface by a distance less than 10 mm; the wheelchair continues to move forward and makes d31 = d32; Step 5: The front walking wheels exceed the step; the wheelchair moves forward intermittently and slowly. When d31 = 0 and L0 = hs + h, it indicates that the center line of the front walking wheels has reached the edge of the step; prepare to lower the front walking wheels; Step 6: The front walking wheels start to lower; assume the forward speed of the wheelchair is v1, and the speeds of the telescopic rod one (212) of linear motor one (21) and the telescopic rod two (222) of linear motor two (22) extending are v2, and the extension amounts L212 = L222 ≈ h - 10. Control the telescopic rod one (212) of linear motor one (21) and the telescopic rod two (222) of linear motor two (22) according to the following rules to make the front walking wheels approach the ground but not touch it: When L212 < 0.3R, V2 = V1 / 2 When 0.3R < L212 < 0.7R, V2 = V1 When L212 > 0.7R, V2 = 2V1 During this process, the wheelchair is driven forward by the left rear drive wheel (43) and the right rear drive wheel (44); after this process, the front walking wheels are only very close to the road surface but not fully on the ground, so the movement of the rear wheels in the subsequent process will not be affected by the friction between the front wheels and the ground, but it can prevent the wheelchair from tipping over; Step 7: Adjust the direction of the wheelchair and lower the front wheels; to keep the wheelchair balanced when the next walking wheel goes down the step, the direction of the wheelchair needs to be adjusted; control the differential speed of the left rear drive wheel and the right rear drive wheel of the wheelchair to make the wheelchair rotate around the left front drive wheel; and use the left front lidar (31) and the right front lidar (32) to measure the distances d31 and d32 of the step; When 0.9R < d31 < 1.1R and 0.9L13 < d32 < 1.1L13 are satisfied, the right front wheel of the wheelchair is equivalent to staying still but not touching the rear step; make d32 ≈ L13, and make the forward direction of the wheelchair form an angle j with the step, and the theoretical value of j is: j = artg (L13 / L12); in this way, the left rear drive wheel has been at the edge of the step and is ready to go down the step; Meanwhile, make the wheelchair rotate around the right front drive wheel to make the right rear wheel ready to go down the step; then, control linear motor one (21) to extend the telescopic rod one (212) and linear motor two to extend the telescopic rod two (222), and the extension amounts L212 = L222 = h, so that the front wheels of the wheelchair land and provide forward power; Step 8: One of the rear drive wheels exceeds the step and touches the ground; control the wheelchair to move forward slowly. The left front drive wheel (41) and the right front drive wheel (42) have completely landed and provide the main walking power. One of the two rear drive wheels close to the step is about to exceed the step and is ready to land; the left rear drive wheel (43) is close to the step. When the wheelchair moves forward, it will make the left rear drive wheel (43) exceed the step and land first. During this process, it is necessary to control linear motor three (23) to make the telescopic rod three (232) extend, thereby driving the left rear drive wheel (43) to descend, and record the extension amount as L232; assume the forward speed of the wheelchair is v1, and the speed of the telescopic rod three (232) of linear motor three (23) extending is v2; control v2 according to the following rules: When L232 < 0.3R, V2 = V1 / 2 When 0.3R < L232 < 0.7R, V2 = V1 When L232 > 0.7R, V2 = 2V1 Until the extension amount L232 = h, make the left rear drive wheel (43) land; Similarly, the right rear drive wheel (44) is close to the step. When the wheelchair moves forward, the right rear drive wheel (44) will first exceed the step. During this process, it is necessary to control the linear motor four (24) to extend the telescopic rod four (242), thereby driving the right rear wheel to descend. Denote the telescopic amount as L242. Assume the forward speed of the wheelchair is v1, and the speed of the linear motor four (24) extending the telescopic rod four (242) is v2. Control v2 according to the following rules: When L242 < 0.3R, V2 = V1 / 2 When 0.3R < L242 < 0.7R, V2 = V1 When L242 > 0.7R, V2 = 2V1 Until the extension amount L242 = h, causing the right rear drive wheel to land; Step 9: The other rear drive wheel approaches the step and is ready to descend and contact the ground At this time, it is necessary to move the last drive wheel on the step near the step; continue to control the wheelchair to move forward slowly at the same speed until the last drive wheel approaches the step; Step 10: The last rear drive wheel descends and contacts the ground; continue to control the wheelchair to move forward slowly until the last drive wheel lands; Step 11: The wheelchair returns to the initial state. When all drive wheels have completed descending the step, it is necessary to simultaneously retract the extended telescopic rod five (202), telescopic rod one (212), telescopic rod two (222), telescopic rod three (232), and telescopic rod four (242), causing the wheelchair seat to descend and the wheelchair to return to the initial state.

3. The intelligent control method for a wheelchair structure capable of ascending and descending stairs according to claim 1, characterized in that: The fixed position of the inclination sensor (6) is not limited to directly above the seat plate, below the seat plate where it is installed, or other positions.

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