Low-power-consumption visual system for centimeter-level micro-robot

Abstract

The invention discloses a low-power-consumption visual system for a centimeter-level micro-robot, which comprises an image sensing unit, a control and communication unit and an information receiving unit, each unit adopts a PCB (Printed Circuit Board) multilayer board structure, and the image sensing unit and the control and communication unit are arranged on a robot body. A signal output port of the image sensing unit is connected with the control and communication unit, the control and communication unit transmits information to the information receiving unit in a Bluetooth wireless transmission mode, and the information receiving unit is connected with an upper computer and transmits image data information to the upper computer in a serial port mode for image data information restoration. The invention also provides an image processing method, which can perform information restoration on the acquired image data and improve the image definition. The low-power-consumption visual system has the advantages of being small in size, low in power consumption, low in cost, free of wires, good in maintainability, high in information transmission real-time performance and the like, and can be carried on a centimeter-level micro-robot to work in a complex environment.

Description

Technical Field

[0001] The present invention relates to the field of industrial vision measurement, and more particularly to a vision system for a micro robot. Background Art

[0002] Micro robots, with their advantages of small size, light weight, and high flexibility, are widely used in various fields, such as medical detection, military reconnaissance, equipment maintenance, etc. Micro robots can carry modules such as communication, control, and monitoring for operation, so as to meet different task requirements. When working in a complex environment, the vision system is an important means for the robot to obtain environmental information. Through the vision system, the micro robot can realize functions such as target recognition and self-positioning. Therefore, the vision system has been widely used in mobile robots.

[0003] Most of the existing vision systems for micro robots are in the gram level in terms of mass, have a large volume, low image resolution, and require wired transmission, which brings inconvenience to the task execution of micro robots and causes them unable to move flexibly in complex environments. Moreover, due to the limited load capacity of micro robots, it is difficult to achieve excellent motion performance after carrying the vision system.

[0004] For vision systems that can achieve wireless image acquisition and data information transmission, they are currently concentrated in the fields of micro aerial vehicles and micro capsule robots, with large mass and size, and there is also the problem of high power consumption (the power consumption is mostly higher than 100 mW), which makes the continuous working time of the robot unable to be guaranteed.

[0005] In summary, the existing vision systems applied to micro robots have problems such as large mass and size, low image resolution, high power consumption, and the need to carry data lines for work, resulting in the inability of micro robots to carry wireless vision modules to move flexibly in complex environments. Summary of the Invention

[0006] Aiming at the deficiencies of the existing vision systems for micro robots, such as large mass and size, high power consumption, and the need for wired work, the present invention proposes a low-power vision system for centimeter-level micro robots.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: A low-power vision system for centimeter-level micro-robots, including an image sensing unit, a control and communication unit, and an information receiving unit. All three units adopt a multi-layer PCB structure. Among them, the image sensing unit and the control and communication unit are the on-board parts, installed on the robot body. The signal output port of the image sensing unit is connected to the control and communication unit. The image sensing unit collects target image data information, and the control and communication unit transmits the image data information to the information receiving unit by wireless transmission. The information receiving unit is connected to the host computer (computer terminal) and transmits the signal to the host computer for restoring the image data information.

[0008] The image sensing unit (hereinafter referred to as the first PCB board) includes a micro camera module, a camera interface, a control and communication unit interface, and a first PCB driving circuit. Among them, the micro camera module includes a lens and a CMOS image sensor, which are used to obtain target optical information and convert it into an electrical signal and transmit it to the control and communication unit. The pins of the image sensor are directly led out as pads; the camera interface is used to connect the camera module to the PCB and is made of flexible circuit board material, which can realize the bending of the micro camera module; the control and communication unit interface is used to connect the image sensing unit and the control and communication unit; the first PCB driving circuit is used to supply power to the image sensing unit and convert the power supply voltage of 3.3V into a stable DC voltage of 2.8V.

[0009] Furthermore, the first PCB board adopts a multi-layer board design with 4 layers or more. Taking the 4-layer solution as an example, components and signal lines are arranged on the first layer and the fourth layer, corresponding to the front and back of the PCB board. The second layer and the third layer are the ground layer and the power layer respectively, and all 4 layers are conductive layers.

[0010] The control and communication unit (hereinafter referred to as the second PCB board) includes a Bluetooth module and a second PCB driving circuit. Among them, the Bluetooth module includes a high-speed crystal oscillator component, a Bluetooth chip, and an antenna, which are used to obtain the image data information from the image sensing unit and transmit it, and receive the information transmitted from the control end and control the movement of the robot; the second PCB driving circuit is used to supply power to the Bluetooth chip.

[0011] Furthermore, the high-speed crystal oscillator component provides a clock signal to ensure the normal operation of the Bluetooth chip. The crystal oscillator clock signal pins are connected to two groups of capacitors to form an oscillation circuit; the Bluetooth chip is used to receive the image data information of the image sensing unit and communicate with the control end and the information receiving unit (the third PCB board); the antenna is used to broadcast the obtained image data in Bluetooth mode and transmit the image data.

[0012] Further, the control and communication unit interface uses pin headers to connect the image sensing unit and the control and communication unit. The connection at one end of the image sensing unit is a pad led out from the pins of the image sensor, and the connection at one end of the control and communication unit is a pad led out from the pins of the Bluetooth chip.

[0013] Further, the second PCB board adopts a multi-layer board design with 4 layers or more. Components and signal lines are arranged on the first layer and the fourth layer. Preferably, the Bluetooth chip, the high-speed crystal oscillator module, and the antenna are arranged on the first layer, and capacitors and inductors are arranged on the fourth layer. The capacitors and inductors are connected to the Bluetooth chip through vias.

[0014] The information receiving unit (hereinafter referred to as the third PCB board) includes a Bluetooth module, an LED module, a USB to serial port module, and a third PCB driving circuit. Among them, the Bluetooth module is used to receive the image data information of the control and communication unit and transmit it to the host computer through the serial port; the LED module is used to display the communication status of the Bluetooth chip; the USB to serial port module includes a USB to serial port chip and a USB female socket, which realizes the conversion from the computer USB interface to the physical serial port and is used to connect to the USB serial port of the host computer to realize the transmission and power supply of image data; the third PCB driving circuit reduces the 5V voltage provided by the USB to a stable DC voltage of 3.3V to supply power to the information receiving unit.

[0015] Further, the third PCB board adopts a multi-layer board design with 4 layers or more, and all 4 layers are conductive layers. Preferably, the Bluetooth module and the LED module are arranged on the first layer, and the USB to serial port module and the driving circuit are arranged on the fourth layer; the USB female socket and the USB to serial port chip are connected by serpentine traces.

[0016] Even further, the line width of the signal lines set on the first PCB board, the second PCB board, and the third PCB board is 6 mil (0.152 mm), and the line width of the power supply line and the ground line is 12 mil (0.305 mm).

[0017] The present invention also provides an image processing method for the above visual system, which can restore the information of the acquired image data and improve the image clarity, including two processes: image preprocessing and image postprocessing.

[0018] Image preprocessing refers to performing image correction in the image sensor by using the configuration register, including bad pixel correction, black level correction, and automatic exposure setting. Bad pixel correction is used to remove defective pixel points in the image acquired by the image sensor; black level correction is used to prevent the picture from color cast and ensure consistent image effects; automatic exposure setting is used to prevent the image from flickering in brightness or the texture from jumping.

[0019] Image post - processing refers to post - processing the images obtained by the host computer (computer side) to improve clarity. Specific post - processing methods include, but are not limited to, image denoising and image enhancement. Image denoising is completed on the Python - OpenCV platform and is performed by median filtering and mean filtering; image enhancement is used to highlight the useful information in the image, facilitating the extraction of image features.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] (1) Small size, low power consumption, and easy integration. The present invention realizes the acquisition and transmission of image information through the first PCB board with an image acquisition device, the second PCB board carrying a Bluetooth module, and the third PCB board connected to the computer. Since the image sensing unit, the control and communication unit, and the information receiving unit all adopt the PCB board structure, and each PCB has at least 4 conductive layers, the functional components of the system of the present invention are highly integrated and combine software and hardware, having the remarkable advantages of small size, light weight, low power consumption, and no need for trailing wires, and can be carried on a centimeter - level micro - robot for work.

[0022] (2) Low cost and good maintainability. The present invention adopts a unitized design, with each unit arranged on a PCB board. Each unit can be used as an independent spare part, and faults can be easily and quickly eliminated and repaired by replacing the PCB board, with good maintainability and low product cost.

[0023] (3) High real - time information transmission and strong human - machine interaction. The present invention uses Bluetooth technology for wireless transmission of image data, and the software on the host computer can display the collected images in real time, with high real - time transmission. The Bluetooth module can be shared by the control and communication unit and the robot control end, and flexible motion control of the robot can be realized through the host computer software while collecting image information, with good human - machine interaction. Brief Description of the Drawings

[0024] Figure 1 It is the overall schematic diagram of the vision system of the present invention.

[0025] Figure 2 is the schematic diagram of the structure of each unit PCB board of the present invention, where Figure 2a and Figure 2b are the on - board parts of the vision system, Figure 2c is the front side of the PCB board of the information receiving unit, Figure 2d is the back side of the PCB board of the information receiving unit.

[0026] Figure 3 is the circuit schematic diagram of the image sensing unit of the present invention, including the circuit schematic diagram of the image sensing unit ( Figure 3a ), the schematic diagram of the first PCB drive circuit ( Figure 3b ).

[0027] Figure 4 is the circuit schematic diagram of the control and communication unit of the present invention, including the circuit schematic diagram of the oscillation circuit ( Figure 4a ), and the circuit schematic diagram of the Bluetooth module interface ( Figure 4b ).

[0028] Figure 5 is the circuit schematic diagram of the information receiving unit of the present invention, including the circuit schematic diagram of the Bluetooth module ( Figure 5a ), the circuit schematic diagram of the LED module ( Figure 5b ), the circuit schematic diagram of the USB to serial port module ( Figure 5c ), and the circuit schematic diagram of the third PCB driving circuit ( Figure 5d ).

[0029] Figure 6 is the flow schematic diagram of the image processing method of the present invention. Specific embodiments

[0030] The present invention will be further described below through a preferred embodiment in conjunction with the accompanying drawings.

[0031] As Figure 1 and shown in Figure 2, the vision system for centimeter-scale micro-robots of the present invention includes an image sensing unit 5, a control and communication unit 8 plugged on the image sensing unit 5, and an information receiving unit 13 connected to the host computer. The image sensing unit 5, the control and communication unit 8, and the information receiving unit 13 are all of PCB board structure and each has at least 4 conductive layers.

[0032] The image sensing unit 5 is provided with a micro camera module 1, a camera interface 2, a control and communication unit interface 3, and a first PCB driving circuit 4, which is used to obtain the target optical information, convert it into an electrical signal, and then transmit it to the control and communication unit 8. The control and communication unit 8 includes a Bluetooth module 6 and a second PCB driving circuit 7, which can transmit the information from the image sensing unit 5 to the information receiving unit 13 in the form of a wireless signal. The information receiving unit 13 is provided with an LED module 9, a Bluetooth module 10, a USB to serial port module 11, and a third PCB driving circuit 12. The information receiving unit 13 is connected to the host computer (computer) and transmits the image data information to the host computer in the form of a serial port.

[0033] The micro camera module 1 includes a lens and a CMOS image sensor, which is used to capture information, convert the captured information into digital image data and transmit it to the control and communication unit (the second PCB board); the micro camera module 1 selects the HM01B0 module, which has only 4mW power consumption and can realize the acquisition of video stream black and white images with a maximum image resolution of 320×320. The signal transmission pins of the image sensor are led out to pads to realize the export of image data.

[0034] The miniature camera module 1 is connected to the PCB board of the image sensing unit 5 through the camera interface 2. In this embodiment, the camera interface 2 uses a 24-pin flexible flat cable connector (SFV24R-1STE1HLF), which can achieve a small bend of the camera module. This connection method facilitates the replacement of the camera module.

[0035] The control and communication unit interface 3 is set as a pin header. The image sensing unit 5 is plugged into the control and communication module 8 through the pin header to achieve electrical connection. Among them, the connection at one end of the image sensing unit 5 is a pad led out by the pins of the image sensor, and the connection at one end of the control and communication unit 8 is a pad led out by the pins of the Bluetooth chip.

[0036] The first PCB driving circuit 4 is used to supply power to the image sensing unit 5. The first PCB driving circuit is connected to the first power supply terminal and the second power supply terminal, and integrates a PAM3101DAB280 linear voltage regulator to achieve the conversion from the first voltage of 3.3V to the second voltage of 2.8V.

[0037] The circuit of the image sensing unit is shown in Figure 3. The signal transmission pins of the image sensor are led out as pads ( Figure 3a P1 in the figure, a total of 9 pins) for connecting to the control and communication unit interface. In the circuit of the image sensing unit, a 0-ohm resistor R3 is used to isolate the analog ground AGND and the digital ground GND to suppress noise.

[0038] The Bluetooth module 6 of the control and communication unit includes a high-speed crystal oscillator component, a Bluetooth chip, and an antenna. Its circuit principle is shown in Figure 4. In this embodiment, the Bluetooth chip selected for receiving and transmitting information is the NRF52832 Bluetooth chip, and the package is QFN48. The high-speed crystal oscillator module is a 32MHz crystal oscillator that provides a clock signal; the clock signal pins of the high-speed crystal oscillator are respectively connected to the clock signal input pins XC1 and XC2 of the Bluetooth chip, and are also connected to capacitors at the same time to form an oscillation circuit. The antenna selects the AN3216 small ceramic Bluetooth antenna as the transmitting antenna, with an impedance matching of 50 ohms, which is used to enhance the signal and facilitate data transmission.

[0039] The second PCB driving circuit 7 for supplying power to the Bluetooth chip is powered by a DC / DC voltage regulator as the core, and the voltage is changed through an LC filter circuit. The output pin of the voltage regulator is connected to the DCC pin of the Bluetooth chip, and the input pin is connected to the DEC4 pin to obtain a pure DC power supply through the filter circuit.

[0040] Preferably, the control and communication unit can share the Bluetooth module with the robot control terminal to simultaneously collect image information during the robot motion control process.

[0041] The signal ports SWDIO and clock port SWDCLK of the Bluetooth chip are led out, and data burning is realized through pin headers or copper wires. Pin D0 and pin PCLK are used to receive the data signal and clock signal of the image sensor, receive the image data information, and the horizontal synchronization signal HSYNC and vertical synchronization signal VSYNC jointly judge the transmission situation of pixel data to realize the communication between the Bluetooth chip and the image sensor. The serial communication pins TXD and RXD are used to connect to the host computer in the form of a serial port for convenient program debugging.

[0042] The information receiving unit 13 includes an LED module 9, a Bluetooth module 10, a USB to serial port module 11, and a third PCB driving circuit 12. It is connected to the host computer and is used to receive the image data transmitted by Bluetooth and realize the transmission of image data to the host computer through the serial port. Fig. 5 shows the circuit schematic diagram of the information receiving unit 13.

[0043] The LED module 9 is used to judge the serial port status of the Bluetooth chip. When in the communication state, the LED light is bright, and the negative electrode of the LED is connected to the Bluetooth chip pins TXD and RXD.

[0044] The Bluetooth module 10 is used to realize the information transmission between the control and communication unit. In this embodiment, the Bluetooth module RF-BM-ND08 is used to realize communication and data transmission. The TXD pin is used as the transmitting pin, and the RXD pin is used as the receiving pin, and it is connected to the USB to serial port module and the LED module. The VCC, GND, SWDCLK, and SWDIO pins of the Bluetooth module need to be led out and connected to the emulator through pin headers for program burning. It should be noted that the Bluetooth modules of the present invention are all burned with image data acquisition and image data transmission programs to realize image data information acquisition and wireless transmission.

[0045] The USB to serial port module 11 is used to realize the conversion between the USB interface of the host computer and the physical serial port. With the CH340 chip as the core, the TXD pin of the CH340 chip is connected to the RXD pin of the Bluetooth module, and the RXD pin of the CH340 chip is connected to the TXD pin of the Bluetooth module to realize communication. The information receiving unit is connected to the host computer through a data line and a micro USB female socket. The differential signals D- and D+ of the micro USB female socket are differentially connected to the CH340 chip, and serpentine traces are used to ensure equal length and proximity.

[0046] The third PCB driving circuit 12 is connected to the micro USB female socket, the Bluetooth chip, and the CH340 chip. The voltage is converted from 5.5V to 3.3V through a voltage stabilizing circuit. The AMS1084CD chip is selected for the voltage stabilizing circuit, and filter capacitors are added at the input voltage port and the output voltage port for voltage stabilization.

[0047] The above-mentioned first, second, and third PCB drive circuits are all used to change the voltage and provide a stable DC voltage for other components.

[0048] The image processing method provided by the present invention is as Figure 6 shown. This method is used to improve the clarity of the acquired image, and its process includes image preprocessing and image postprocessing. Image preprocessing refers to performing dead pixel correction, black level correction, and automatic exposure setting in the image sensor by configuring registers. Image postprocessing refers to processing the acquired image on the host computer, including image denoising, image enhancement, etc. Image postprocessing is based on the Python-OpenCV platform, selects the method of image filtering for image denoising, and uses histogram equalization for image enhancement.

[0049] Preferably, for the scenario of large equipment maintenance applications of centimeter-scale micro-robots, the image processing method of the present invention can extract the crack feature information of the captured picture through image edge detection, and at the same time provide an evaluation of the picture clarity.

[0050] In this example, the on-board PCB board of the vision system on the centimeter-scale micro-robot part is as Figure 2a and Figure 2b shown. The overall mass is about 800 mg, the overall size is 15 mm × 22 mm, and the surface area is 330 mm 2 , in the data transmission state, the maximum power consumption is 67 mW. The camera module can be bent. When moving on the centimeter-scale micro-robot, it can achieve a black-and-white video stream transmission of 2.5 frames per second. When using the Tenengrad function to evaluate the image clarity, the image clarity obtained by the host computer is far higher than that of the reference image.

[0051] What is not elaborated in detail in the present invention belongs to the well-known technology in the art.

[0052] The above are only examples of the present invention, and do not impose any form of limitation on the present invention. Any simple modification, equivalent change, and modification made to the above examples based on the principle and technical essence of the present invention still fall within the scope of the technical solution of the present invention. Therefore, the protection scope of the present invention shall be subject to the claims.

Claims

1. A low-power vision system for centimeter-level microrobots, characterized in that: The robot comprises an image sensing unit (5), a control and communication unit (8) and an information receiving unit (13), wherein the image sensing unit (5) and the control and communication unit (8) are mounted on a robot body, a signal output port of the image sensing unit (5) is connected to the control and communication unit (8), the image sensing unit (5) collects target image data information, the control and communication unit (8) transmits the image data information to the information receiving unit (13) by wireless transmission, and the information receiving unit (13) is connected to a host computer and transmits the image data information to the host computer in the form of a serial port to restore the image data information; The image sensing unit (5) comprises a micro camera module (1) for acquiring target optical information and converting it into electrical signals to be transmitted to the control and communication unit (8); The control and communication unit (8) comprises a Bluetooth module (6) for transmitting the image data information from the image sensing unit (5) to the information receiving unit via Bluetooth technology; The information receiving unit (13) comprises a Bluetooth module (10) and a USB to serial port module (11); wherein the Bluetooth module (10) is programmed with an image data acquisition program and an image data transmission program, receives image data information from the control and communication unit (8), and transmits the information to a host computer via a serial port; the USB to serial port module (11) comprises a USB to serial port chip and a USB female socket, realizes the conversion from a computer USB interface to a physical serial port, and is used to connect to the USB serial port of the host computer to realize image data transmission and power supply; The image sensing unit (5), the control and communication unit (8) and the information receiving unit (13) all adopt a PCB multilayer structure; each is provided with a PCB drive circuit for changing the voltage to provide a stable DC voltage for other components on the PCB.

2. The low-power vision system for centimeter-level microrobots according to claim 1, characterized in that: The image sensing unit (5) also includes a camera interface (2), and the micro camera module (1) is connected to a PCB board via the camera interface (2). The camera interface (2) is made of a flexible circuit board material, and the micro camera module can be bent.

3. The low-power vision system for centimeter-level microrobots as claimed in claim 2, characterized in that: The flexible circuit board material is a 24-pin flexible flat cable connector.

4. The low-power vision system for centimeter-level microrobots according to claim 1, characterized in that: The micro camera module (1) comprises a lens and a CMOS image sensor, and the pins of the image sensor are directly led out to form pads, thereby realizing image data export.

5. The low-power vision system for centimeter-level microrobots according to claim 1, characterized in that: The Bluetooth module (6) comprises a high-speed crystal oscillator component, a Bluetooth chip and an antenna. The high-speed crystal oscillator component provides a clock signal. The crystal oscillator clock signal pin is connected to two groups of capacitors to form an oscillation circuit. The Bluetooth chip is used to receive image data information from the image sensing unit (5) and communicate with the information receiving unit (13). The antenna is used to broadcast the acquired image data in a Bluetooth manner and transmit the image data.

6. The low-power vision system for centimeter-level microrobots according to claim 1, characterized in that: The control and communication unit (8) is plugged into the image sensor unit (5) via a pin header, wherein the connection point at one end of the image sensor unit (5) is a pad from which the image sensor pins are led out, and the connection point at one end of the control and communication unit (8) is a pad from which the Bluetooth chip pins are led out.

7. The low-power vision system for centimeter-level microrobots according to any one of claims 1 to 6, characterized in that: The PCB multilayer board structure is a 4-layer board design, all of which are conductive layers. The first and fourth layers are used to arrange components and signal lines, corresponding to the front and back sides of the PCB board, and the second and third layers are ground and power layers, respectively.

8. The low-power vision system for centimeter-level microrobots as claimed in claim 7, characterized in that: In the image sensing unit circuit, the analog ground AGND and the digital ground GND are isolated by a 0 ohm resistor R3 to suppress noise.

9. The low-power vision system for centimeter-level microrobots according to claim 7, characterized in that: The Bluetooth module (6) can be used by the control and communication unit (8) and the robot control terminal, thereby realizing image information collection and robot motion process control at the same time.

10. An image processing method, characterized in that: Used to restore information on image data acquired by the low-power vision system described in claim 1 and improve image clarity, including two processes: image preprocessing and image postprocessing; image preprocessing is to perform image correction in the image sensor by configuring registers, including bad pixel correction, black level correction and automatic exposure setting; image postprocessing includes image noise reduction and image enhancement.

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