LoRa-based low-power-consumption roof pressure acquisition method

Abstract

The invention relates to a LoRa-based low-power-consumption roof pressure acquisition method, and belongs to the field of wireless communication. The problems that an existing coal mine underground roof pressure monitoring system is high in power consumption, prone to being interfered by the environment, low in data transmission reliability and the like are solved. According to the method, a LoRa wireless transmission technology is adopted, and a fixed data transmission time slot is distributed for each sensor through a time division multiplexing technology and a passive transmission technology, so that information collision is avoided, and the data transmission reliability is improved. The sensor adopts a low-power-consumption design, and further reduces the power consumption and prolongs the service life of a battery through hardware power supply partition control and a software sleep wake-up mechanism. The method has the advantages of being simple in algorithm logic, low in system cost, high in applicability and the like, the stability and reliability of the coal mine underground roof pressure monitoring system can be effectively improved, and a powerful guarantee is provided for safe production.

Description

Technical Field

[0001] The invention belongs to the field of wireless communications and relates to a low-power consumption roof pressure acquisition method based on LoRa. Background Art

[0002] In the fully-mechanized mining face of coal mines, hydraulic supports are prone to automatic lowering, dead support, and overturning. At present, hydraulic support pressure detection systems are mostly established. At the earliest, the monitoring system mostly used wired transmission, but in the process of advancing the working face, the monitoring line was easily destroyed, causing the system to be paralyzed, and was gradually replaced by a wireless system. At present, there are generally two implementation methods in the wireless roof pressure monitoring system. One is to use a repeater to build a network and receive and upload data to a switch or transmission substation; the other is to build a wireless routing node and build a star network to upload data to the transmission substation. There are problems such as inability to sleep and high power consumption when transmitting data through a repeater, as well as high system cost and easy damage to cables. By building a star network with wireless routing, the relay is easily interrupted, which can easily cause data loss during data transmission, reducing the possibility of data monitoring in the pressure monitoring system. At the same time, the relay power consumption is high, and the terminal equipment generally uses disposable batteries. If there is a failure in data transmission, it is easy to cause the sensor to be disconnected from the network and unable to enter sleep mode, resulting in a reduced battery life, which brings inconvenience to users in use and maintenance.

[0003] Based on the above problems, coal mine roof pressure monitoring requires a wireless low-power detection method. If a wireless method is used, a low-power pressure data acquisition method based on Lora can solve the current problem. It can realize wireless transmission and solve the current wired communication and wireless routing problems through passive network access based on time division multiplexing technology. At the same time, this method has low power consumption and improves CPU utilization.

[0004] In summary, in order to improve the stability and convenience of the pressure monitoring system and meet the ever-changing market demands, a wireless sensor low-power pressure acquisition method is urgently needed. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a low-power roof pressure acquisition method based on LoRa. This method requires the cooperation of a wireless transmission substation, which has one RS485 channel and one LoRa channel. LoRa is used to allocate data transmission time slots to the sensor and obtain the roof pressure data frame of the sensor, and RS485 is used to upload pressure data. The sensor has one LoRa channel for sensor registration and uploading of roof pressure data. The peripheral power partition control and time-sharing multiplexing working mode are adopted to reduce system power consumption. The technical design of the invention has the following advantages: simple algorithm logic, low system cost and strong applicability.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A low-power consumption roof pressure collection method based on LoRa, the method comprising the following steps:

[0008] Set up a server and a wireless transmission substation. The wireless transmission substation has one LoRa channel and one RS485 channel. The LoRa channel is used to allocate data transmission time slots to the sensor and obtain the top plate pressure data frame of the sensor. The RS485 channel is used to upload the top plate pressure data.

[0009] The sensor has a LoRa channel for uploading collected roof pressure data in coal mines;

[0010] Passive transmission is adopted. The wireless transmission substation sends a registration frame, the sensor is awakened from the dormant state, and sends a registration request frame. The wireless transmission substation receives the registration request frame, registers the sensor and allocates a transmission time slot to avoid information collision.

[0011] Furthermore, the sensor achieves low power consumption through hardware power partition control and software sleep and wake-up collaboration.

[0012] Furthermore, the sensor has four modes: standby mode, data collection mode, wireless transceiver mode and debugging mode. The CPU works in sleep / standby mode. After being awakened by the wireless transmission substation to register with the network, it wakes up in the transmission time slot to upload pressure information. At other times, it is awakened by the timer to collect pressure.

[0013] Furthermore, the sensor adopts time division multiplexing technology. Through passive network access, the pressure acquisition substation sends a registration broadcast frame to wake up the sensor from a sleep state, and then sends a broadcast frame to allocate a working time slot for each sensor. The pressure sensor can only upload within the specified working time slot, that is, there is only one sensor communicating with the substation in each working time slot, avoiding information collision problems caused by multiple sensors uploading information at the same time.

[0014] The beneficial effects of the present invention are:

[0015] (1) The wireless transmission substation uses the LoRa channel to broadcast the registration frame data packet. The LoRa channel of the sensor receives the registration frame. If it is not registered, it sends a registration request frame. It only needs to passively receive the data collection time slot frame. Otherwise, it enters the dormant state and is awakened by the timer during the life cycle to collect the roof pressure.

[0016] (2) The invention adopts wireless transmission, and there is no need to establish a wired cable transmission system, which saves manpower and resources and avoids line damage during construction. It adopts time division multiplexing technology and passive transmission technology to allocate a fixed data transmission time slot for each sensor, without the need to add gateways or routing devices, which not only avoids information collision during pressure collection and improves system reliability, but also reduces the waste of resources and power caused by adding gateways or laying routes;

[0017] (3) During the pressure collection process, it is only necessary to lay a wireless transmission substation to complete the roof pressure collection work, without laying lines or setting gateway parameters.

[0018] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is the architecture diagram of the sensor top plate pressure acquisition system;

[0021] Figure 2 Design block diagram for positioning card hardware;

[0022] Figure 3 Design a block diagram for the pressure acquisition sensor software;

[0023] Figure 4 It is the working mode conversion relationship diagram of the pressure acquisition sensor;

[0024] Figure 5 Assign time slots to data collection;

[0025] Figure 6 This is the flow chart of the anti-collision algorithm. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0027] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0028] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0029] (1) System architecture

[0030] During the process of sensor collecting pressure, it is necessary to set up a server and a wireless transmission substation. The wireless transmission substation has one LoRa channel and one RS485 channel. The LoRa channel allocates data transmission time slots to the sensor to obtain the sensor's roof pressure data frame. RS485 is used to upload the roof pressure data. The sensor has a LoRa channel, which is used to upload the collected coal mine roof pressure data. In the process of the sensor collecting roof pressure, a passive transmission method is first adopted. The wireless transmission substation sends a registration frame, the sensor is awakened from the sleep state, and a registration request frame is sent. The wireless transmission substation receives the registration request frame, registers the sensor and allocates a transmission time slot to avoid information collision. The system architecture diagram is shown below. Figure 1 shown.

[0031] In the process of collecting roof pressure data by the sensor, the wireless transmission base station uses a broadcast mechanism to send registration frames, and the sensor can only passively receive and wake up. The sensor transmits data in the time slot specified by the protocol. The data transmission time is extremely short, and the data transmission lasts only 6ms. This method has low power consumption, improves CPU utilization, and solves the current wired communication and wireless routing problems.

[0032] (2) Sensor hardware design

[0033] In order to improve the sensor's low power consumption and high performance, the sensor design includes four parts: Lora wireless acquisition, power control, display module and FLASH. The hardware design block diagram is as follows Figure 2 As shown in the figure, the sensor contains one LoRa channel and one external FLASH.

[0034] The LED display circuit includes light-sensitive wake-up, power drive, scanning control and LED display; the data acquisition unit is based on the ASR6505 spread spectrum low-power chip design to achieve data interaction; the microcontroller is in low-power mode and is controlled by the I / O pin to achieve low-power control of the peripheral circuit. The wireless pressure monitoring sensor power design block diagram is as follows Figure 3 As shown in the figure, the software uses external power partitioning to further reduce the power consumption of the sensor. The battery voltage is stabilized and divided into three power supply routes. The CPU and wireless transceiver module are stably powered. The CPU adopts two modes: sleep and normal operation. It is awakened by peripherals when there is a task. Light-sensitive wake-up, over-limit alarm, and breakpoint resume use interrupt wake-up, and the power supply is controlled by the CPU. The power detection and pressure collection are controlled by the timer to turn on the power at a fixed time to start the corresponding task.

[0035] (3) Low power consumption mechanism

[0036] The low power consumption of the sensor is achieved through the collaboration of hardware power partition control and software sleep and wake-up. The sensor mainly consists of three modules: the main control center, the LED display module, and the LoRa wireless transmission. The CPU mainly works in sleep / standby mode. After being awakened by the wireless transmission substation to register with the network, it wakes up in the transmission time slot to upload pressure information. At other times, it is awakened by the timer to collect pressure. The LED display module is controlled by the CPU for power supply. In order to reduce power consumption, it is only turned on in debugging mode; the LoRa module is only awakened in the transmission state. The sensor has four modes: standby mode, data acquisition mode, wireless transceiver mode, and debugging mode. The working mode conversion relationship diagram is shown below. Figure 4 As shown in the figure, 1 indicates external signal triggering, 2 indicates timer triggering, 3 indicates receiving wireless transceiver instructions, 4 indicates receiving wireless transceiver instructions, 5 indicates the end of data collection, 6 indicates the end of debugging, and 7 indicates the end of wireless transceiver (see Figure 4 ).

[0037] The sensor power supply is partitioned and supplied by three power supplies respectively. The main control CPU and wireless transceiver module are constantly powered, and the peripheral debugging circuit is powered by the CPU. When the sensor parameters need to be set or adjusted, the CPU is woken up by the peripheral interrupt, and the CPU controls the I / O to turn on the peripheral voltage. When not needed, the peripherals and clock are turned off. The data acquisition circuit is awakened by the CPU internal timer interrupt to periodically monitor the top plate pressure.

[0038] (4) Data collection and transmission

[0039] When there are many sensors, if the sensors upload the collected pressure data at the same time, it will inevitably cause information collision, resulting in pressure data information loss, affecting the system detection accuracy and success rate. Using time division multiplexing technology, the pressure collection substation sends a registration broadcast frame through the passive access of the sensor to wake up the sensor from the sleep state, and then sends a broadcast frame to allocate a working time slot for each sensor. The pressure sensor can only upload in the specified working time slot, that is, there is only one sensor communicating with the substation in each working time slot, avoiding the information collision problem caused by multiple sensors uploading information at the same time. The data collection time slot allocation is as follows: Figure 5 shown.

[0040] The sensor starts the data collection task when the timer is interrupted. When the substation receives the registration information packet of the sensor in the registration time slot, it analyzes the sensor ID, allocates the positioning time slot for the sensor, and sends the time slot broadcast frame to the sensor. After receiving the data packet, the sensor sends online information to the substation regularly. If the sensor does not respond for a long time, the substation removes the data of the card in the registration data packet, and the sensor can re-apply for registration. The anti-collision algorithm flow chart is as follows Figure 6 shown.

[0041] In the present invention, the wireless transmission substation has one LoRa channel and one RS485 channel.

[0042] The LoRa channel of the wireless transmission substation is used to broadcast registration frame data packets.

[0043] The RS485 channel of the wireless transmission substation is used to collect the top plate pressure data detected by the sensor.

[0044] The sensor has a LoRa channel for uploading the collected roof pressure data in the coal mine. In the process of collecting roof pressure, the sensor first adopts the passive transmission mode to receive the registration frame sent by the wireless transmission substation.

[0045] The sensor adopts a power partition design, is awakened by a timer interrupt to collect top plate pressure, and is awakened by LoRa information to receive registration frame data packets.

[0046] Embodiment 1:

[0047] Wireless transmission substation: Using LoRa technology, equipped with one LoRa channel and one RS485 channel. The LoRa channel is used to broadcast registration frame data packets and allocate data transmission time slots for each sensor. The RS485 channel is used to receive the roof pressure data uploaded by the sensor and transmit it to the monitoring center.

[0048] Sensor: Equipped with a LoRa channel for receiving registration frames and uploading top plate pressure data. The sensor contains a pressure sensor, a microcontroller, a power management module, and a memory. The sensor adopts a low-power design, and the power consumption is extremely low in standby mode. It only wakes up to work when data is collected and transmitted.

[0049] Embodiment 2:

[0050] Wireless transmission substation: Using LoRa technology, equipped with one LoRa channel and one RS485 channel. The LoRa channel is used to broadcast registration frame data packets and allocate data transmission time slots for each sensor. The RS485 channel is used to receive the roof pressure data uploaded by the sensor and transmit it to the monitoring center.

[0051] Sensor: Equipped with a LoRa channel for receiving registration frames and uploading top plate pressure data. The sensor contains a pressure sensor, a microcontroller, a power management module, a display module, and a memory. The sensor adopts a low-power design, and the power consumption is extremely low in standby mode. It only wakes up to work when data is collected and transmitted. The display module is used to display the sensor status and collected data, which is convenient for on-site personnel to monitor and maintain.

[0052] The main difference between the two embodiments is whether the sensor is equipped with a display module. A sensor equipped with a display module can facilitate on-site personnel to monitor and maintain, but the power consumption will increase slightly.

[0053] Both embodiments use LoRa technology and time division multiplexing technology to achieve low-power, high-reliability roof pressure collection and transmission.

[0054] Wireless transmission substations and sensors can adopt different hardware platforms and software designs, but they need to meet the requirements of the LoRa protocol and implement time division multiplexing and data transmission functions.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A low-power roof pressure acquisition method based on LoRa, characterized in that: The method comprises the following steps: Set up a server and a wireless transmission substation. The wireless transmission substation has one LoRa channel and one RS485 channel. The LoRa channel is used to allocate data transmission time slots to the sensor and obtain the top plate pressure data frame of the sensor. The RS485 channel is used to upload the top plate pressure data. The sensor has a LoRa channel for uploading collected roof pressure data in coal mines; Passive transmission is adopted. The wireless transmission substation sends a registration frame, the sensor is awakened from the dormant state, and sends a registration request frame. The wireless transmission substation receives the registration request frame, registers the sensor and allocates a transmission time slot to avoid information collision.

2. The low-power consumption roof pressure acquisition method based on LoRa according to claim 1, characterized in that: The sensor achieves low power consumption through hardware power partition control and software sleep and wake-up collaboration.

3. The low-power consumption roof pressure acquisition method based on LoRa according to claim 2 is characterized in that: The sensor has four modes: standby mode, data collection mode, wireless transceiver mode and debugging mode. The CPU works in sleep / standby mode. After being awakened by the wireless transmission substation to register with the network, it wakes up in the transmission time slot to upload pressure information. At other times, it is awakened by the timer to collect pressure.

4. The low-power consumption roof pressure acquisition method based on LoRa according to claim 1, characterized in that: The sensor adopts time division multiplexing technology. Through passive network access, the pressure acquisition substation sends a registration broadcast frame to wake up the sensor from a dormant state, and then sends a broadcast frame to allocate a working time slot for each sensor. The pressure sensor can only upload within the specified working time slot, that is, there is only one sensor communicating with the substation in each working time slot, avoiding information collision problems caused by multiple sensors uploading information at the same time.

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