Ball odometer and mileage calculation method

Abstract

The present invention discloses a ball bearing odometer and a mileage calculation method. The ball bearing odometer comprises a ball, a ball bearing bracket, a displacement sensor, and a bottom support plate. The ball bearing bracket is disposed on the bottom support plate, and the ball bearing is rotatably disposed in the ball bearing bracket. One side of the ball bearing passes through the ball bearing bracket and abuts against a contact surface. The displacement sensor is disposed on the ball bearing bracket to detect the rolling of the ball bearing. The ball bearing odometer of the present invention has a simple structure and is easy to produce. The ball bearing and a commonly used displacement sensor are combined to obtain rolling data of the ball bearing by detecting the rolling motion of the ball bearing. Through simple calculation, the precise mileage and even detailed walking trajectory of a mobile robot on a highly reflective or transparent smooth surface can be obtained. The mileage calculation method is simple, easy to use, and has a small error.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile robot navigation and positioning, and in particular to a ball odometer and a mileage calculation method. Background Art

[0002] The traditional method of calculating mileage by calculating the distance a roller rolls only provides mileage along one axis. To more accurately calculate mileage, new mobile robots generally use optical flow sensors. Optical flow sensors calculate mileage by measuring the movement of an image viewed by an optical lens. This solution can measure mileage along both the x and y axes of a plane and works well. However, it fails on highly reflective or transparent surfaces, making it unsuitable for mobile robots operating in challenging environments, such as window cleaning robots. Summary of the Invention

[0003] In response to the above-mentioned problem that the odometers in the prior art cannot be used on highly reflective or transparent surfaces, the present invention provides a ball odometer and a mileage calculation method using the ball odometer. A ball is set in the odometer, and then a displacement sensor is used to monitor the rolling mileage of the ball, and the displacement and direction of the robot on the contact plane are indirectly obtained. This can not only be used to calculate the moving mileage of the mobile robot, but also to obtain the moving trajectory of the mobile robot on the contact plane.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a ball odometer, provided with a ball, a ball bracket, a displacement sensor and a bottom support plate, the ball bracket is arranged on the bottom support plate, the ball is rollably arranged in the ball bracket, one side of the ball passes through the ball bracket and abuts against the contact plane, and the displacement sensor is arranged on the ball bracket to detect the rolling of the ball.

[0005] The technical solution adopted by the present invention to solve the technical problem further includes:

[0006] As described above, the ball odometer, the ball bracket includes a support shaft, a bearing and a base plate, the support shaft is provided with more than three and is arranged around the ball, the number of the bearings is twice the number of the support shafts, the bearings are respectively arranged at the ends of the support shafts and connected to the base plate, the diameter of the polygonal inscribed circle where the support shaft is located is smaller than the diameter of the ball, the support shaft abuts against the outer surface of the ball, so that the support shaft rotates as the ball rolls.

[0007] In the ball odometer as described above, the displacement sensor is an optical flow sensor, which is arranged on one side of the ball, and the camera of the optical flow sensor is arranged toward the ball.

[0008] In a ball odometer as described above, the ball bracket is provided with a ball cover plate, the ball is arranged between the support shaft and the ball cover plate, the ball cover plate is provided with a ball hole with a radius smaller than the ball, and the ball is rotatably installed in the ball hole.

[0009] In a ball odometer as described above, the displacement sensor is an encoder, and there are more than two encoders. The encoders are respectively arranged on two or more adjacent support shafts. The code disk of the encoder is connected to the support shaft and rotates with the support shaft, and the encoder is connected to a counter.

[0010] In the ball odometer as described above, the encoder is a photoelectric encoder or a magnetic encoder.

[0011] As described above, in a ball odometer, the bottom support plate and the ball bracket are connected by a connecting column, and the connecting columns are provided with more than two and are arranged parallel to each other, one end of the connecting column is fixedly connected to the bottom support plate, and the other end of the connecting column is movably connected to the ball bracket, so that the ball bracket can reciprocate along the connecting column; a reset spring is mounted on the connecting column, one end of the reset spring abuts against the bottom support plate, and the other end of the reset spring abuts against the ball bracket.

[0012] The ball odometer as described above, the ball bracket includes a support shaft, a bearing, a base plate and a ball cover plate, the ball cover plate is arranged on the front side of the ball, and a ball hole with a radius smaller than the ball is provided on the ball cover plate, the ball can be rotatably embedded in the ball hole and contacts the contact plane through the ball hole, the support shaft is arranged on the rear side of the ball, the support shaft is provided with three and arranged in a triangle around the ball, the bearings are provided with six, the bearings are respectively arranged at both ends of the support shaft and connected to the base plate, the inscribed circle diameter of the triangle formed by the support shaft is smaller than the diameter of the ball, the support shaft abuts against the outer surface of the ball, so that the ball is confined in the ball hole; the bottom support plate and the ball cover plate are connected by four parallel connecting columns, the bottom plate is provided with a through hole for the connecting column to pass through, and the connecting column is provided with a reset spring, one end of the reset spring abuts against the bottom support plate, and the other end of the reset spring abuts against the ball bracket.

[0013] In the ball odometer as described above, the displacement sensor is an optical flow sensor, which is arranged on the bottom plate behind the ball, with the camera of the optical flow sensor facing the ball, and a lens is provided between the optical flow sensor and the ball.

[0014] A method for calculating mileage using a ball odometer as described above, characterized in that it comprises the following steps:

[0015] S10, establishing a plane rectangular coordinate system with the intersection of two adjacent support shafts, axis a and axis b, provided with encoders, as the origin, wherein the angle between the rotation direction of axis a and the x-axis is α, and the angle between the rotation direction of axis b and the x-axis is β;

[0016] S20, the ball odometer moves, the ball rolls and drives shaft a and shaft b to rotate, and the displacement sensor obtains the displacement L1 of shaft a and the displacement L2 of shaft b per unit time of the ball odometer;

[0017] S30, calculating the endpoint coordinates (x, y) of the ball odometer within a unit time, x = L1*cos(α) = L2*cos(β), y = L2*sin(α) = L2*sin(β);

[0018] S40, calculate the distance L between the end point and the origin,

[0019] S50, it takes n units of time for the ball bearing odometer to move from the initial starting point to the final destination, calculate L1, L2...Ln corresponding to n units, add L1 to Ln to obtain the total mileage of the ball bearing odometer.

[0020] The beneficial effects of the present invention are: the ball odometer of the present invention has a simple structure and is easy to produce. It combines the ball with a commonly used displacement sensor, and obtains the rolling data of the ball by detecting the rolling action of the ball. After simple calculation, the precise mileage and even detailed walking trajectory of the mobile robot on a highly reflective or transparent smooth surface can be obtained. It is also minimally affected by the use environment and has a very long service life. The corresponding mileage calculation method is simple, easy to use, and has a small error. It can not only obtain accurate mileage data, but also is very convenient for measuring the walking path of the mobile robot, which is convenient for later path planning and control.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the vertical cross-section structure of the first embodiment of the ball odometer of the present invention;

[0023] Figure 2 A schematic horizontal cross-sectional view of a first embodiment of a ball odometer according to the present invention;

[0024] Figure 3 A schematic horizontal cross-sectional view of a second embodiment of a ball odometer according to the present invention;

[0025] Figure 4 This is a schematic diagram of the horizontal cross-section structure of the third embodiment of the ball odometer of the present invention;

[0026] In the figure, 1, ball bearing, 21, support shaft, 22, bearing, 23, bottom plate, 24, ball bearing cover plate, 241, ball bearing hole, 31, optical flow sensor, 311, lens, 321, grating code disk, 322, photoelectric detection device, 331, Hall effect disk, 332, Hall effect sensing device, 4, bottom support plate, 41, connecting column, 42, return spring. DETAILED DESCRIPTION

[0027] This embodiment is a preferred implementation manner of the present invention. Other embodiments whose principles and basic structures are the same or similar to those of this embodiment are within the scope of protection of the present invention.

[0028] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0030] The first embodiment of the ball odometer of the present invention refers to Figure 1 and 2 As shown, there are provided a ball 1, a ball bracket, a displacement sensor and a bottom support plate 4. The ball bracket is arranged on the bottom support plate 4. The ball 1 is rotatably arranged in the ball bracket. One side of the ball 1 passes through the ball bracket and abuts against the contact plane. The displacement sensor is arranged on the ball bracket to detect the rolling of the ball 1.

[0031] In this embodiment, the ball bearing bracket is used to fix the ball 1. The ball bearing bracket includes a support shaft 21, a bearing 22, a base plate 23, and a ball bearing cover plate 24. The ball 1 is arranged between the support shaft 21 and the ball bearing cover plate 24. The ball bearing cover plate 24 is arranged in front of the ball 1 and is provided with a ball bearing hole 241 having a radius smaller than that of the ball 1. The ball 1 is rotatably embedded in the ball bearing hole 241 and contacts the contact surface through the ball bearing hole 241. The support shaft 21 is arranged on the rear side of the ball 1. There are three support shafts 21 and they are arranged in a triangle around the ball 1. The diameter of the inscribed circle of the triangle formed by the support shafts 21 is smaller than the diameter of the ball 1, so that the support shaft 21 abuts against the outer surface of the ball 1. The ball 1 can drive the support shaft 21, and the support shaft 21 can limit the ball 1 in the ball hole 241; there are six bearings 22, and the bearings 22 are respectively arranged at both ends of the support shaft 21 and connected to the base plate 23, so that the support shaft 21 is installed on the base plate 23, and when the ball 1 rolls, the support shaft 21 can roll smoothly with the ball 21. The bottom support plate 4 is arranged behind the ball bracket. The bottom support plate 4 and the ball cover plate 24 are connected by four parallel connecting columns 41. A through hole is provided on the bottom plate 23 for the connecting column 41 to pass through. A return spring 42 is provided on the connecting column 41. One end of the return spring 42 abuts against the bottom support plate 4, and the other end of the return spring 42 abuts against the ball bracket, so that the ball bracket is pressed toward the contact plane, and the ball 1 arranged in the ball bracket keeps in contact with the contact plane.

[0032] In this embodiment, the displacement sensor is an optical flow sensor 31. The optical flow sensor 31 is arranged on the bottom plate 23 on the rear side of the ball 1. The camera of the optical flow sensor 31 is facing the ball 1. Due to the obstruction of the ball 1 and the ball cover 24, light will not directly enter the camera of the optical flow sensor, making the optical flow sensor 31 ineffective. In order to make the optical flow sensor 31 monitor the rolling action of the ball 1 more accurately, a lens 311 is provided between the optical flow sensor 31 and the ball 1 to magnify the surface of the ball 1. When the mobile robot moves, the optical flow sensor 31 can establish a plane rectangular coordinate system by analyzing the surface image of the ball 1, calculate the displacement of the ball 1 in the x and y directions, and then calculate the movement distance of the mobile robot. By analyzing the movement distance and direction per unit time, an accurate walking route can also be obtained.

[0033] The second embodiment of the ball odometer of the present invention refers to Figure 3As shown, there are a ball 1, a ball holder, a displacement sensor and a bottom support plate 4. The ball holder is set on the bottom support plate 4. The ball 1 is rotatably set in the ball holder. One side of the ball 1 passes through the ball holder and abuts the contact plane. The displacement sensor is set on the ball holder to detect the rolling of the ball 1. The ball holder includes a support shaft 21, a bearing 22 and a bottom plate 23. The support shaft 21 is provided with three and is arranged in a triangular shape around the ball 1. The diameter of the inscribed circle of the triangle formed by the support shaft 21 is smaller than the diameter of the ball 1, so that the support shaft 21 abuts the outer surface of the ball 1, the ball 1 can drive the support shaft 21, and the support shaft 21 can confine the ball 1 in the ball hole 241. There are six bearings 22, which are respectively provided at both ends of the support shaft 21 and connected to the bottom plate 23, so that the support shaft 21 is installed on the bottom plate 23. When the ball 1 rolls, the support shaft 21 can roll smoothly with the ball 21.

[0034] The displacement sensor in this embodiment is a photoelectric encoder. Two photoelectric encoders are provided, each disposed at one end of two adjacent support shafts 21. The photoelectric encoders are equipped with a grating code disk 321 and a photoelectric detection device 322. The two grating code disks 321 are respectively connected to corresponding support shafts 21 and rotate with the support shafts 21. The photoelectric detection device 322 of the photoelectric encoder monitors the rotation of the grating code disks 321 and sends a pulse signal to a counter connected to the encoder. Based on the received pulse signal, the counter calculates the displacement of the mobile robot in the rotation direction of the corresponding support shaft 21, calculates the coordinates of the end point in a plane rectangular coordinate system established with the intersection of the two support shafts 21 as the origin, and further calculates the movement distance and trajectory of the mobile robot.

[0035] The third embodiment of the ball odometer of the present invention refers to Figure 4 As shown, there are a ball 1, a ball holder, a displacement sensor and a bottom support plate 4. The ball holder is set on the bottom support plate 4. The ball 1 is rotatably set in the ball holder. One side of the ball 1 passes through the ball holder and abuts the contact plane. The displacement sensor is set on the ball holder to detect the rolling of the ball 1. The ball holder includes a support shaft 21, a bearing 22 and a bottom plate 23. The support shaft 21 is provided with three and is arranged in a triangular shape around the ball 1. The diameter of the inscribed circle of the triangle formed by the support shaft 21 is smaller than the diameter of the ball 1, so that the support shaft 21 abuts the outer surface of the ball 1, the ball 1 can drive the support shaft 21, and the support shaft 21 can confine the ball 1 in the ball hole 241. There are six bearings 22, which are respectively provided at both ends of the support shaft 21 and connected to the bottom plate 23, so that the support shaft 21 is installed on the bottom plate 23. When the ball 1 rolls, the support shaft 21 can roll smoothly with the ball 21.

[0036] The displacement sensor in this embodiment is a magnetic encoder, which includes a Hall disk 331 and a Hall sensor 332. The magnetic encoders are respectively arranged at one end of two adjacent support shafts 21. The Hall disks 331 are respectively connected to the corresponding support shafts 21 and rotate with the support shafts 21. The Hall sensing device 332 monitors the rotation of the Hall disk 331 and sends a pulse signal to the counter connected to the encoder. The counter calculates the displacement of the mobile robot in the rotation direction of the corresponding support shaft 21 based on the received pulse signal, calculates the coordinates of the end position in the plane rectangular coordinate system established with the intersection of the two support shafts 21 as the origin, and then calculates the moving mileage and trajectory of the mobile robot.

[0037] In the actual production process, the number of support shafts 21 can be increased as needed and set to four mutually perpendicular ones. The encoders are set on two adjacent support shafts 21. Then, the straight line where the two support shafts 21 are located can be directly used to establish a plane rectangular coordinate system as the x-axis and y-axis. The rotational displacement of the two support shafts 21 per unit time is the coordinate of the end point. The distance formula between the two points can be used to calculate the mileage of the mobile robot per unit time.

[0038] The present invention further provides a method for calculating mileage using the ball odometer of the second or third embodiment, comprising the following steps:

[0039] S10, establishing a plane rectangular coordinate system with the intersection of two adjacent support shafts, axis a and axis b, provided with encoders, as the origin, wherein the angle between the rotation direction of axis a and the x-axis is α, and the angle between the rotation direction of axis b and the x-axis is β;

[0040] S20, the ball odometer moves, the ball rolls and drives shaft a and shaft b to rotate, and the displacement sensor obtains the displacement La of shaft a and the displacement Lb of shaft b per unit time of the ball odometer;

[0041] S30, calculating the endpoint coordinates (x, y) of the ball odometer within a unit time, x = La*cos(α) = Lb*cos(β), y = La*sin(α) = Lb*sin(β);

[0042] S40, calculate the distance L between the end point and the origin,

[0043] S50, it takes n units of time for the ball bearing odometer to move from the initial starting point to the final destination, calculate L1, L2...Ln corresponding to n units, add L1 to Ln to obtain the total mileage of the ball bearing odometer.

[0044] The ball odometer of the present invention has a simple structure and is easy to produce. It combines a ball with a commonly used displacement sensor, and obtains the rolling data of the ball by detecting the rolling action of the ball. After simple calculation, the precise mileage and even detailed walking trajectory of the mobile robot on a highly reflective or transparent smooth surface can be obtained. It is also minimally affected by the use environment and has a very long service life. The corresponding mileage calculation method is simple, easy to use, and has a small error. It can not only obtain accurate mileage data, but also is very convenient for measuring the walking path of the mobile robot, which is convenient for subsequent path planning and control.

Claims

1. A ball odometer, characterized in that: A ball (1), a ball bracket, a displacement sensor and a bottom support plate (4) are provided, wherein the ball bracket is arranged on the bottom support plate (4), the ball (1) is arranged in a rollable manner in the ball bracket, one side of the ball (1) passes through the ball bracket and abuts against a contact plane, and the displacement sensor is arranged on the ball bracket to detect the rolling of the ball (1); The ball support comprises a support shaft (21), a bearing (22) and a base plate (23), wherein the support shaft (21) is provided with more than three and is arranged around the ball (1), the number of the bearings (22) is twice the number of the support shaft (21), the bearings (22) are respectively arranged at the ends of the support shaft (21) and connected to the base plate (23), the diameter of the polygonal inscribed circle where the support shaft (21) is located is smaller than the diameter of the ball (1), the support shaft (21) abuts against the outer surface of the ball (1), so that the support shaft (21) rotates as the ball (1) rolls; The displacement sensor is an optical flow sensor (31), and the optical flow sensor (31) is arranged on one side of the ball (1), and a camera of the optical flow sensor (31) is arranged toward the ball (1).

2. The ball odometer according to claim 1, wherein: The ball support is provided with a ball cover plate (24), the ball (1) is arranged between the support shaft (21) and the ball cover plate (24), the ball cover plate (24) is provided with a ball hole (241) having a radius smaller than that of the ball (1), and the ball (1) is rotatably mounted in the ball hole (241).

3. The ball odometer according to claim 1, wherein: The displacement sensor is replaced by an encoder, and more than two encoders are provided. The encoders are respectively arranged on more than two adjacent support shafts (21). The code disk of the encoder is connected to the support shaft (21) and rotates with the support shaft (21), and the encoder is connected to a counter.

4. The ball odometer according to claim 3, wherein: The encoder is a photoelectric encoder or a magnetic encoder.

5. The ball odometer according to claim 1, wherein: The bottom support plate (4) and the ball support bracket are connected via a connecting column (41). The connecting column (41) is provided with two or more connecting columns that are arranged parallel to each other. One end of the connecting column (41) is fixedly connected to the bottom support plate (4), and the other end of the connecting column (41) is movably connected to the ball support bracket, so that the ball support bracket can reciprocate along the connecting column (41). A return spring (42) is sleeved on the connecting column (41), one end of the return spring (42) abuts against the bottom support plate (4), and the other end of the return spring (42) abuts against the ball support bracket.

6. The ball odometer according to claim 1, wherein: The ball support comprises a support shaft (21), a bearing (22), a bottom plate (23) and a ball cover plate (24), wherein the ball cover plate (24) is arranged at the front side of the ball (1), and a ball hole (241) having a radius smaller than that of the ball (1) is provided on the ball cover plate (24), and the ball (1) is rotatably embedded in the ball hole (241) and contacts the contact plane through the ball hole (241), and the support shaft (21) is arranged at the rear side of the ball (1), and the support shaft (21) is provided with three and arranged in a triangular shape around the ball (1), and the bearings (22) are provided with six, and the bearings (22) are respectively arranged at both ends of the support shaft (21). The bottom support plate (4) and the ball cover plate (24) are connected to the bottom plate (23), the diameter of the inscribed circle of the triangle formed by the support shaft (21) is smaller than the diameter of the ball (1), and the support shaft (21) abuts against the outer surface of the ball (1), so that the ball (1) is confined in the ball hole (241); the bottom support plate (4) and the ball cover plate (24) are connected by four parallel connecting columns (41), the bottom plate (23) is provided with a through hole for the connecting column (41) to pass through, and the connecting column (41) is provided with a return spring (42), one end of the return spring (42) abuts against the bottom support plate (4), and the other end of the return spring (42) abuts against the ball bracket.

7. The ball odometer according to claim 6, wherein: The displacement sensor is an optical flow sensor (31), which is arranged on the bottom plate (23) on the rear side of the ball (1), with a camera of the optical flow sensor (31) facing the ball (1), and a lens is provided between the optical flow sensor (31) and the ball (1).

8. A method for calculating mileage using the ball odometer according to any one of claims 3 or 4, characterized in that: The following steps are involved: S10, establish a plane rectangular coordinate system with the intersection of two adjacent support shafts (21) with encoders, axis a and axis b, as the origin. The angle between the rotation direction of axis a and the x-axis is α, and the rotation direction of axis b is The angle between the direction and the x-axis is β; S20, the ball odometer moves, the ball (1) rolls and drives the axis a and axis b to rotate, and the displacement sensor obtains the displacement L1 of the axis a and the displacement L2 of the axis b per unit time of the ball odometer; S30, calculate the end point coordinates (x, y) of the ball odometer per unit time, x = L1 * cos (α) = L2 * cos (β), y = L2 * sin (α) = L2 * sin (β); S40, calculate the distance L between the end point and the origin, L= ; S50, the ball bearing odometer moves from the initial starting point to the final destination after n units of time, and L1, L2, ..., Ln corresponding to the n units are calculated. L1 to Ln are added together to obtain the total mileage of the ball bearing odometer.

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