A photoelectric cliff sensor and mobile robot

Abstract

This utility model discloses a photoelectric cliff sensor and a mobile robot, relating to the field of cliff sensor technology. The photoelectric cliff sensor includes a circuit board, a transmitter, a receiver, a transmitting lens, a receiving lens, a first convex lens, and a second convex lens. The transmitter is mounted on the circuit board; the receiver is mounted on the circuit board; a partition is provided between the transmitter and the receiver; the transmitting lens is located in the transmitting light path of the transmitter, and the transmitter has a first divergence angle; the receiving lens is located in the receiving light path of the receiver, and the receiver has a first field of view; the first convex lens is located on the back of the transmitting lens and near the partition, used to refract a portion of the infrared emitted light into the range of the first divergence angle; the second convex lens is located on the back of the receiving lens and near the partition on the other side, used to increase the range of the first field of view. This sensor can improve the near-field blind zone problem while maintaining long-distance detection performance.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to a photoelectric cliff sensor and a mobile robot. Background Technology

[0002] Photoelectric cliff sensors are sensors that detect whether there are cliffs (steps) in front of a machine. They are commonly used in robotic vacuum cleaners, transport robots, and some self-moving devices. For example, robots often encounter cliffs (steps, stairs, thresholds) during operation. To prevent them from falling, cliff sensors need to be installed on the machines to identify cliffs and thus avoid falls.

[0003] Ordinary photoelectric sensors have blind spots, which can cause them to fail to detect nearby black objects, such as black blankets. Furthermore, the current size of cliff sensors is limited, making it difficult to improve the near-field blind spot while maintaining long-range detection performance. Utility Model Content

[0004] This invention provides a photoelectric cliff sensor and a mobile robot to solve the technical problem that photoelectric cliff sensors in the prior art cannot identify objects at close range due to the large blind zone.

[0005] To address the aforementioned problems, the primary objective of this utility model is to provide a photoelectric cliff sensor, comprising:

[0006] Circuit board;

[0007] A transmitter is mounted on the circuit board and is used to emit infrared light signals with a preset horizontal field of view.

[0008] A receiver is mounted on the circuit board. The receiver is used to receive the reflected light signal after the infrared light signal is reflected by an obstacle, and to image the reflected light signal. A partition is provided between the transmitter and the receiver.

[0009] A transmitting lens is disposed in the transmitting optical path of the transmitter, and the transmitting lens enables the transmitter to have a first divergence angle;

[0010] A receiving lens is disposed in the receiving optical path of the receiver, and the receiving lens enables the receiver to have a first field of view.

[0011] A first convex lens is disposed on the back of the emitting lens and located on the side close to the partition. The first convex lens is used to refract a portion of the infrared emitted light into the first field of view.

[0012] A second convex lens is disposed on the back of the receiving lens and on the other side near the partition. The second convex lens is used to increase the first field of view range.

[0013] Preferred options also include:

[0014] A signal transmission terminal is disposed on the circuit board, and the signal transmission terminal is electrically connected to the receiver and the transmitter respectively, so as to enable signal transmission between the transmitter and the receiver; and / or,

[0015] The connector is electrically connected to the signal transmission terminal.

[0016] Preferably, the partition is a triangular structure, with the base of the triangular structure located between the transmitter and the receiver, and the apex of the triangular structure located between the first convex lens and the second convex lens.

[0017] Preferably, it also includes a housing, wherein the housing has a receiving cavity, and the transmitter, receiver and partition are all disposed within the receiving cavity;

[0018] The transmitting lens and the receiving lens are mounted on the supporting wall of the housing, and the supporting wall is a light-transmitting wall; wherein, the supporting wall is the wall of the housing through which the emitted light from the transmitter passes and the incident light from the receiver passes.

[0019] Preferably, the incident surface of the transmitting lens is a plane, and the exiting surface of the transmitting lens protrudes in a direction away from the transmitter; the incident surface of the receiving lens protrudes in a direction away from the receiver, and the exiting surface of the receiving lens is a plane.

[0020] Preferably, the first divergence angle is 5-35° and the first field of view is 40-80°.

[0021] Preferably, the housing has a first opening at the position corresponding to the insertion end of the connector, the connector is located at the first opening, and the outer edge of the connector is flush with the edge of the first opening.

[0022] Preferably, both the first convex lens and the second convex lens are spherical or polygonal structures.

[0023] Preferably, both the transmitter and the receiver are surface-mount infrared emitting LEDs or laser emitting components.

[0024] The second objective of this invention is to provide a mobile robot, including a body and a photoelectric cliff sensor as described above, wherein the photoelectric cliff sensor is disposed at the bottom of the body.

[0025] Compared with the prior art, this utility model has significant advantages and beneficial effects, specifically reflected in the following aspects:

[0026] The photoelectric cliff sensor of this invention uses a first convex lens to refract a portion of the emitted infrared light into a first divergence angle range. This allows the emitted light to cover areas that might otherwise be blind spots at close range, giving more reflected light a chance to be received by the receiver, thus improving the near-range blind spot situation. Simultaneously, by using a second convex lens, the receiver's first field of view is increased. This means that in the near-range area, the receiver can receive signals reflected from a wider angle. Even if obstacles are located at different positions near the sensor, as long as they are within the expanded field of view, their reflected light can be captured, further compensating for near-range detection blind spots and improving the sensitivity and reliability of near-range detection. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the changes in the laser emission and reception field of view of the photoelectric cliff sensor in this embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the photoelectric cliff sensor in an embodiment of the present invention;

[0029] Figure 3 A schematic diagram illustrating the structure used to improve the blind zone formed at the intersection of the forward divergence angle and the edge of the field of view.

[0030] Figure 4 This is a schematic diagram of the optical path to reduce the blind zone by increasing the distance between the transmitter and receiver;

[0031] Figure 5 This is a schematic diagram illustrating the working principle of the photoelectric cliff sensor in this embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Circuit board; 2-Transmitter; 3-Receiver; 4-Transmitting lens; 5-Receiving lens; 6-First convex lens; 7-Second convex lens; 8-Separator; 9-Outer shell. Detailed Implementation

[0034] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0035] Currently, the working principle of existing photoelectric cliff sensors is as follows: The sensor is generally installed at the bottom of the robot. The infrared emitting device emits an infrared light with a certain divergence angle. After being collimated and focused by an optical convex lens, the light is directed towards the ground at a certain angle. When the sensor is within a safe distance from the ground, the infrared light will hit the field of view of the receiving lens and be received by the infrared receiving device, outputting a signal value. If the sensor is too far from the ground, exceeding the height that the robot can cross, the infrared light will hit outside the field of view of the receiving lens, and no signal value will be output.

[0036] Please see Figure 3 , 4 As shown, since a blind zone is formed at the intersection of the divergence angle and the edge of the field of view of the lens, when the sensor is very close to the object being measured, the infrared light will not be able to hit the field of view of the receiving lens, which will lead to false alarms.

[0037] To address the aforementioned issues, the common solution is to increase the distance between the infrared transmitter and receiver to reduce the near-range blind spot. However, this forces a reduction in the safe height at long ranges, leading to a decrease in the robot's obstacle-crossing ability. Figure 4 As shown.

[0038] To solve the above problems, such as Figure 1-2 As shown, an embodiment of this utility model provides a photoelectric cliff sensor, which includes a circuit board 1, a transmitter 2, a receiver 3, a transmitting lens 4, a receiving lens 5, a first convex lens 6, and a second convex lens 7, wherein:

[0039] The circuit board 1 serves as the foundation for support and circuit connections. A partition 8 is provided between the transmitter 2 and the receiver 3. This effectively prevents the emitted light from directly entering the receiver 3, avoiding self-interference at close range and ensuring the accuracy and stability of the signal during long-distance detection. The transmitter 2 is mounted on the circuit board 1 and is used to emit infrared light signals with a preset horizontal field of view. The emitting lens 4 is located in the emission light path of the transmitter 2, giving the transmitter 2 a first divergence angle. The infrared light signal emitted by the transmitter 2 is collimated or focused by the emitting lens 4 to form a specific first divergence angle. A first convex lens 6 is located on the back of the emitting lens 4 and near the partition 8. It refracts a portion of the infrared emitted light that would otherwise have a near-distance blind zone due to direct propagation, allowing it to enter the first field of view range, thereby expanding the effective coverage range of the emitted light at close range.

[0040] Receiver 3 is mounted on circuit board 1. Receiver 3 is used to receive the reflected light signal after the infrared light signal is reflected by the obstacle, and to image the reflected light signal. Receiver lens 5 is disposed in the receiving optical path of receiver 3 to collect and focus the reflected light signal. Receiver lens 5 enables receiver 3 to have a first field of view. Second convex lens 7 is disposed on the back of receiver lens 5 and on the other side near the partition 8. Second convex lens 7 is used to increase the range of the first field of view, so that reflected light signals from a wider angle can be received at close range, avoiding the loss of reflected light in the close range due to a narrow field of view, thereby solving the problem of blind spots at close range.

[0041] Traditional photoelectric cliff sensors may have a near-range blind zone, meaning they cannot effectively detect obstacles within a certain distance near the sensor. The transmitter 2's original design, with its emitting lens 4 and preset horizontal divergence angle, was intended to ensure that the emitted light could propagate at an appropriate angle and energy to a greater distance during long-range detection, guaranteeing that distant obstacles would reflect back a signal of sufficient strength for the receiver 3 to receive. This solution, however, uses a first convex lens 6 to refract a portion of the infrared emitted light into the first field of view, allowing the emitted light to cover the previously existing blind zone at close range. This gives more of the reflected light a chance to be received by the receiver 3, thus improving the near-range blind zone. Simultaneously, the second convex lens 7 at the receiver end increases the first field of view of the receiver 3. This means that in the near-range area, the receiver 3 can receive signals reflected from a wider angle. Even if an obstacle is located at different positions near the sensor, as long as it is within the expanded field of view, its reflected light can be captured, further compensating for the near-range detection blind zone and improving the sensitivity and reliability of near-range detection.

[0042] Specifically, in one embodiment of this utility model, the photoelectric cliff sensor further includes a signal transmission terminal and a connector (not shown in the figure), wherein:

[0043] Signal transmission terminals are located on the circuit board 1 and are electrically connected to the receiver 3 and transmitter 2, respectively, for signal transmission between the transmitter 2 and receiver 3. Connectors are electrically connected to the signal transmission terminals. The signal transmission terminals serve to converge and guide signals, ensuring that signals from different sources are effectively guided to subsequent processing stages or external connections. When the photoelectric cliff sensor needs to be connected to an external system or device, a reliable connection to the external circuit is achieved through the connector. The signal transmission terminals transmit signals from inside the sensor to the connector, which then transmits the signals to the external control unit, processing equipment, or other related components, thus completing the complete signal transmission link from inside the sensor to the outside.

[0044] Preferably, please refer to Figure 1, 2 As shown, the partition 8 has a triangular structure, with the base of the triangular structure located between the transmitter 2 and the receiver 3, and the apex of the triangular structure located between the first convex lens 6 and the second convex lens 7.

[0045] Therefore, by designing the partition 8 as a triangular structure and placing its base between the transmitter 2 and the receiver 3, the emitted light is effectively blocked from directly entering the receiver 3, reducing optical crosstalk at close range. At the same time, the apex is located between the first convex lens 6 and the second convex lens 7, so that the light path after the emitted light is refracted by the first convex lens 6 can better cover the close-range area, increasing the probability of receiving reflected light from close-range obstacles, thereby facilitating the improvement of the close-range blind spot problem.

[0046] For more details, please refer to Figure 1 , 2 As shown, the photoelectric cliff sensor also includes a housing 9, which has a cavity inside. The transmitter 2, receiver 3 and partition 8 are all disposed inside the cavity.

[0047] The transmitting lens 4 and the receiving lens 5 are mounted on the supporting wall of the housing 9, and the supporting wall is a light-transmitting wall; wherein the supporting wall is the wall of the housing 9 facing the emitted light from the transmitter 2 and through which the incident light from the receiver 3 passes.

[0048] Therefore, the outer shell 9 provides a relatively closed and stable internal environment for core components such as transmitter 2, receiver 3 and partition 8, which can effectively block the entry of external dust, moisture, debris and other contaminants, avoid these factors from causing pollution or damage to the internal components, improve the reliability and service life of the sensor in harsh environments, and enable it to better adapt to various practical application environments, such as outdoor and industrial sites.

[0049] For more details, please refer to Figure 1 , 2 As shown, the incident surface of the transmitting lens 4 is a plane, and the exiting surface of the transmitting lens 4 protrudes away from the transmitter 2; the incident surface of the receiving lens 5 protrudes away from the receiver 3, and the exiting surface of the receiving lens 5 is a plane.

[0050] The incident surface of the emitting lens 4 is a plane, which receives the infrared light signal from the transmitter 2. The exit surface of the emitting lens 4 protrudes away from the transmitter 2, forming a convex surface. When the infrared light signal enters the emitting lens 4 from the plane incident surface, it undergoes internal optical transmission and reaches the convex exit surface. According to optical principles, the light will be refracted at the exit surface, thereby forming a specific first divergence angle. This collimates or focuses the light before it is emitted, meeting the light intensity and coverage requirements for long-distance detection.

[0051] The incident surface of the receiving lens 5 protrudes away from the receiver 3, forming a convex surface. When the reflected light signal enters the receiving lens 5 from the outside, it first comes into contact with this convex incident surface, where the light is refracted and begins to be collected and focused, causing the diverging reflected light to gradually converge. The light then propagates in the direction adjusted inside the receiving lens 5, eventually focusing the reflected light onto the receiver 3 so that the receiver 3 can accurately receive and image the light.

[0052] Preferably, the first divergence angle is 5-35°. This range of field of view can effectively balance the coverage and intensity of the emitted light. The smaller field of view allows the emitted light to maintain high intensity and good collimation at long distances, ensuring that obstacles at a distance can reflect back a signal of sufficient strength for the receiver 3 to receive, which helps maintain the sensitivity and reliability of long-distance detection.

[0053] The first field of view is 40-80°, which significantly improves the receiver 3's ability to receive near-field reflected light. The wide field of view can cover a wider area, so that light reflected from near-field obstacles, even if it comes from different angles, can be effectively collected by the receiving lens 5 and focused onto the receiver 3, thereby effectively improving the near-field blind spot problem and increasing the sensitivity of near-field detection.

[0054] For more details, please refer to Figure 1 , 2 As shown, the housing 9 has a first opening corresponding to the insertion end of the connector. The connector is located at the first opening, and the outer edge of the connector is flush with the edge of the first opening. This design makes the insertion and removal of the connector more convenient, allowing users to easily install and remove the connector, facilitating sensor maintenance and debugging.

[0055] For more details, please refer to Figure 1 , 2 As shown, both the first convex lens 6 and the second convex lens 7 are spherical or polygonal structures. The spherical convex lens has a smooth curved surface, which can uniformly refract and converge light; the regular polygonal convex lens produces a specific refraction effect through the combination of multiple planes.

[0056] In another embodiment of this utility model, both the transmitter 2 and the receiver 3 are surface-mount infrared emitting LEDs or laser emitting components.

[0057] When transmitter 2 is a patch-type infrared emitting LED, it emits a modulated infrared light signal, which is collimated or focused by the emitting lens 4 to form a parallel beam or a specific light cone with a preset field of view. The emitted infrared light signal is reflected when it encounters an obstacle. Receiver 3 is a patch-type infrared receiving LED, which receives the reflected light signal and converts the light signal into an electrical signal. The signal processing circuit amplifies and filters the signal to extract effective information and determine the position and distance of the obstacle.

[0058] If transmitter 2 is a laser emitting device, it emits a laser beam. After the laser beam is collimated by the emitting optical system, it is directed toward the target area. The laser signal reflected back after encountering an obstacle is received by receiver 3. Receiver 3 is also a dedicated receiving module for laser emitting devices, which can accurately detect the laser signal and work with the signal processing unit to perform high-precision distance measurement and environmental perception.

[0059] Another embodiment of this utility model provides a mobile robot, which includes a body and the aforementioned photoelectric cliff sensor, wherein the photoelectric cliff sensor is disposed at the bottom of the body.

[0060] Since this mobile robot adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0061] Although the present invention has been disclosed above, its protection scope is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. An optical cliff sensor, characterized in that include: Circuit board; A transmitter is mounted on the circuit board and is used to emit infrared light signals with a preset horizontal field of view. A receiver is mounted on the circuit board. The receiver is used to receive the reflected light signal after the infrared light signal is reflected by an obstacle, and to image the reflected light signal. A partition is provided between the transmitter and the receiver. A transmitting lens is disposed in the transmitting optical path of the transmitter, and the transmitting lens enables the transmitter to have a first divergence angle; A receiving lens is disposed in the receiving optical path of the receiver, and the receiving lens enables the receiver to have a first field of view. A first convex lens is disposed on the back of the emitting lens and located on the side close to the partition. The first convex lens is used to refract a portion of the infrared emitted light into the first field of view. A second convex lens is disposed on the back of the receiving lens and on the other side near the partition. The second convex lens is used to increase the first field of view range.

2. The photoelectric cliff sensor according to claim 1, characterized in that Also includes: A signal transmission terminal is disposed on the circuit board, and the signal transmission terminal is electrically connected to the receiver and the transmitter respectively, so as to enable signal transmission between the transmitter and the receiver; And / or, The connector is electrically connected to the signal transmission terminal.

3. The photoelectric cliff sensor of claim 1, wherein, The partition is a triangular structure, with the base of the triangle located between the transmitter and the receiver, and the apex of the triangle located between the first convex lens and the second convex lens.

4. The photoelectric cliff sensor according to claim 2, characterized in that, It also includes a housing, which has a receiving cavity inside, and the transmitter, receiver and partition are all disposed in the receiving cavity; The transmitting lens and the receiving lens are mounted on the supporting wall of the housing, and the supporting wall is a light-transmitting wall; wherein, the supporting wall is the wall of the housing through which the emitted light from the transmitter passes and the incident light from the receiver passes.

5. The photoelectric cliff sensor according to claim 4, characterized in that, The incident surface of the transmitting lens is a plane, and the exiting surface of the transmitting lens protrudes away from the transmitter; the incident surface of the receiving lens protrudes away from the receiver, and the exiting surface of the receiving lens is a plane.

6. The photoelectric cliff sensor according to claim 1, characterized in that, The first divergence angle is 5-35°, and the first field of view is 40-80°.

7. The photoelectric cliff sensor according to claim 4, characterized in that, The housing has a first opening at the position corresponding to the insertion end of the connector, the connector is located at the first opening, and the outer edge of the connector is flush with the edge of the first opening.

8. The photoelectric cliff sensor according to claim 1, characterized in that, Both the first convex lens and the second convex lens are spherical or polygonal structures.

9. The photoelectric cliff sensor according to claim 2, characterized in that, Both the transmitter and the receiver are surface-mount infrared emitting LEDs or laser emitting components.

10. A mobile robot, characterized in that, It includes a fuselage and a photoelectric cliff sensor as described in any one of claims 1-9, wherein the photoelectric cliff sensor is disposed at the bottom of the fuselage.

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