A platform-based inertial navigation wireless transmission system and method

Abstract

A platform-based inertial navigation wireless transmission system and method are disclosed. The wireless transmission system is divided into a power supply module and a communication module. The power supply module is further divided into a platform power supply module and a motor power supply module. The platform power supply module is used to introduce the external input voltage of the platform inertial navigation system, and after inter-stage wireless conversion, provide power to the relevant control board circuits inside the platform. The motor power supply module is used to provide power to the motor drive and control circuits in the base, outer frame, middle frame, and inner frame axis system, driving the motors so that the outer frame, middle frame, inner frame, and platform rotate around their respective axes. The wireless communication module is used to realize communication between the interface control circuit boards of the base, outer frame, middle frame, inner frame, and platform.

Description

Technical Field

[0001] This invention belongs to the fields of communication and power transmission and inertial navigation technology. Background Technology

[0002] Platform-type inertial navigation systems are used to measure the velocity, position, and attitude information of a carrier. They mainly consist of inertial instruments (gyroscopes and accelerometers), related circuits (including computers and power supplies), a platform, a frame system, and a stabilization loop. The inertial instruments are mounted on the platform, and bearings, torque motors, encoders, and conductive slip rings are installed at each frame axis. Platform-type inertial navigation systems include three-axis or four-axis systems, such as... Figure 2 Currently, conductive slip rings are commonly used for communication and power transmission between various frames in platform-based inertial navigation systems. A conductive slip ring assembly typically consists of a conductive slip ring body, brush assembly, combined support, and radial ball bearing assembly. Due to the mechanical friction of the conductive slip ring, poor contact and even electrical sparks can occur. Furthermore, prolonged wear can easily lead to the accumulation of foreign matter, significantly reducing system stability and reliability. Improving the performance of conductive slip rings or finding alternatives has always been a goal pursued in platform-based inertial navigation systems.

[0003] In recent years, a type of slip ring called a "hybrid optoelectronic slip ring" has emerged. This refers to a slip ring body that contains both a traditional conductive slip ring for transmitting electrical energy and a fiber optic slip ring for transmitting signals. Fiber optic slip rings have advantages such as large signal transmission capacity, long distance, and low loss, but they require a photoelectric conversion device, and their performance will degrade in strong radiation environments.

[0004] Wireless transmission includes wireless communication and wireless power transmission.

[0005] Common wireless communication methods include Bluetooth, Wi-Fi, Zigbee, RF, and NFC. These methods all have relatively complex protocols and have shortcomings in terms of real-time performance, reliability, and communication speed. However, due to their high carrier frequencies, they can achieve relatively long transmission distances and wide coverage. For platform-based inertial navigation systems, high real-time signal communication, high transmission speed, and high reliability are required, while the signal coverage is limited to a set range.

[0006] Wireless power transfer (WPT) technology is classified into microwave WPT, capacitive coupling WPT, and magnetic induction coupling WPT according to different energy coupling methods.

[0007] Microwave power transmission (WPT) technology utilizes high-frequency electromagnetic waves between 300MHz and 300GHz for power transmission. Due to the advantages of microwaves, such as good directionality and the ability to penetrate the ionosphere, long-distance power transmission is possible. Disadvantages include low efficiency and large size.

[0008] Capacitively coupled power transfer (WPT) technology uses an electric field as a medium to transmit electrical energy. Advantages: strong penetration through metal barriers and low electromagnetic interference. Disadvantages: low transmission capacity.

[0009] Magnetic induction coupling (WPT) technology is a technique that uses a magnetic field as a medium to transfer electrical energy. Its working principle is described in [link to WPT technology]. Figure 1 It converts electrical energy into a high-frequency magnetic field, and then couples the electrical energy to the receiving end through magnetic field coupling. This technology has been widely used in medical devices, electric vehicles, and home appliances. Magnetic induction coupling (WPT) has advantages such as high transmission efficiency, high power, no radiation during transmission, and low electromagnetic interference. However, as the air gap distance increases, the leakage flux of the primary and secondary coils increases, causing a sharp drop in the transmission efficiency of the WPT system. Therefore, magnetic induction WPT systems can only achieve high transmission efficiency over relatively short distances (approximately a few centimeters).

[0010] Due to the complexity and numerous constraints of platform-based inertial navigation systems, replacing conductive slip rings with wireless transmission technology is challenging. To enable the application of wireless transmission technology in platform-based inertial navigation systems, the following four requirements must be met for wireless signal transmission: a. Good real-time performance, high transmission rate, and high reliability; b. Maximum signal delay after multi-stage transmission not exceeding 5µs; c. No interference to the system's internal or external systems, meeting electromagnetic compatibility requirements; d. Sufficiently small structural size and weight to meet system requirements and facilitate maintenance. For wireless power transmission, the following four requirements must be met: a. Single-stage transmission efficiency not less than 90%, reducing the power consumption of the wireless transmission system itself; b. Meeting the power supply requirements of each stage of the system after multi-stage transmission; c. No interference to the system's internal or external systems, meeting electromagnetic compatibility requirements; d. Sufficiently small structural size and weight to meet system requirements and facilitate maintenance. Summary of the Invention

[0011] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a platform-type inertial navigation wireless transmission method to realize internal signal communication and power transmission, eliminate the hidden dangers of electrical interference and reliability reduction caused by conductive slip rings in platform-type inertial navigation, and improve the system's anti-interference capability and reliability.

[0012] The technical solution of this invention is: a platform-type inertial navigation wireless transmission system, wherein the platform-type inertial navigation is a four-axis system, including inertial instruments, a platform body, a frame system, and a stabilization loop; the inertial instruments are mounted on the platform body, the platform body is mounted inside the frame system, and the wireless transmission system is mounted within the rotation axis system of the frame system; the frame system consists of an O-shaped frame and corresponding rotation axis systems; a four-axis platform-type inertial navigation system consists of four levels of frames and rotation axis systems, from the outside to the inside, the four levels of O-shaped frames are a base, an outer frame, a middle frame, and an inner frame, and their corresponding... The shaft system comprises a base shaft system, an outer frame shaft system, a middle frame shaft system, and an inner frame shaft system. Each O-shaped frame and its rotation axis form a "Φ" shape, where "O" represents the frame, the vertical bar in the middle is the rotation axis of that frame, and the intersection of the O-shaped frame and the rotation axis is the rotation shaft system of that frame. The rotation shaft systems of each frame level serve the same function, providing support and transmitting motion; that is, the base provides support and transmits motion for the outer frame, the outer frame for the middle frame, the middle frame for the inner frame, and the inner frame for the platform body. The rotation shaft system includes: bearings, a torque motor, an encoder, and a wireless transmission system.

[0013] The wireless transmission system in the rotating axis system is used to transmit electrical energy and communication signals from the outside of the platform inertial navigation system to the platform body, providing electrical energy and control signals to the inertial instruments inside the platform body. The wireless transmission system is divided into a power supply module and a communication module. The power supply module is further divided into a platform body power supply module and a motor power supply module. The platform body power supply module is used to introduce the input voltage from the outside of the platform inertial navigation system, and after inter-stage wireless conversion, provide power to the relevant control board circuits inside the platform body. The motor power supply module is used to provide power to the motor drive and control circuits in the base, outer frame, middle frame, and inner frame axis system, driving the motors, thereby causing the outer frame, middle frame, inner frame, and platform body to rotate around their respective axes. The wireless communication module is used to realize communication between the interface control circuit boards of the base, outer frame, middle frame, inner frame, and platform body.

[0014] The platform power supply module consists of a coupler and a conversion circuit. The coupler is composed of a coupler stator and a coupler rotor. Electrical energy from an external power source is converted into magnetic energy by the conversion circuit on the base and the coupler stator mounted on the base. At the same time, the coupler stator couples the magnetic energy to the coupler rotor through space. The coupler rotor converts the magnetic energy into electrical energy and transmits the electrical energy to the coupler stator mounted on the outer frame. Then, the coupler stator on the outer frame transmits electrical energy to the middle frame in the same way as the base. This process is repeated from the middle frame to the inner frame, and from the inner frame to the platform, realizing the conversion of electrical energy to magnetic energy and magnetic energy to electrical energy step by step. Finally, the external power supply is transmitted to the platform wirelessly.

[0015] The motor power supply module consists of a coupler and a conversion circuit. The coupler is composed of a coupler stator and a coupler rotor. Electrical energy from an external power source is converted into magnetic energy by the conversion circuit on the base and the coupler stator mounted on the base. Simultaneously, the coupler stator couples the magnetic energy to the coupler rotor through space. The coupler rotor converts the magnetic energy into electrical energy. This electrical energy is transmitted to the coupler stator mounted on the outer frame on one hand, and converted into power supply for the outer frame equipment by the conversion circuit on the outer frame on the other hand, thus powering the motor drive and related control circuits of the outer frame. Similar to the wireless power transmission method from the base to the outer frame, electrical energy is converted into magnetic energy and then back to electrical energy step by step from the outer frame to the middle frame and from the middle frame to the inner frame, thus powering the motor drive and related control circuits of each frame.

[0016] The wireless communication module consists of a coupler and a conversion circuit. The coupler consists of a coupler stator and a coupler rotor. The wireless communication module enables communication between the platform interface control circuit board and the interface control circuit boards on the base, outer frame, middle frame, and inner frame. The main control node of the wireless communication system is the platform, and the other frames are the terminal nodes of the communication system.

[0017] The command-data interaction process of the wireless communication module is as follows:

[0018] 1) The platform sends the read action command to the platform's wireless communication conversion circuit board. The conversion circuit modulates the command and sends it to the coupler stator in the form of electromagnetic waves through the coupler rotor on the inner frame. The conversion circuit in the coupler stator demodulates the electromagnetic waves and restores them to the action command. This command is sent to the wireless communication conversion circuit in the middle frame for modulation and is sent to the coupler stator in the form of electromagnetic waves through the coupler rotor on the middle frame for step-by-step transmission. On the other hand, the command is sent to the interface control circuit board on the inner frame. After receiving the command, the interface control circuit board parses the data and determines whether the terminal node of the command is the inner frame. If it is the inner frame, it responds to the command request; otherwise, it does not perform any work.

[0019] 2) The command is transmitted to the base interface control circuit board in the manner described above. The interface control circuit board parses the data and determines that the command is an action command. Then, it sends the data corresponding to the command to the wireless communication conversion circuit board of the base. The conversion circuit modulates the data and sends it to the coupler rotor in the form of electromagnetic waves through the coupler stator on the base. The data is transmitted to the interface control circuit board of the platform in the opposite direction in the same manner as described in step 1).

[0020] 3) In summary, this completes one command and data interaction process between the platform and the base.

[0021] The communication module, platform power supply module, and motor power supply module in the wireless transmission system are all installed at the two ends of each frame shaft system. The shaft ends of each frame shaft system have been designed to be shaftless, that is, mounting flanges and mounting holes are designed on the stationary and moving rings of the bearings, which realizes the installation and fixation of the bearings without shaft parts. At the same time, the other components at the shaft ends of each frame, such as the torque motor, encoder, stator and rotor of each coupling body of the wireless transmission system, adopt a highly integrated and integrated design, which realizes the installation and fixation of all components at the shaft ends, and provides a guarantee for the overall compact design of the machine.

[0022] A platform-based inertial navigation wireless transmission method includes:

[0023] The platform sends the read action command to the platform's wireless communication conversion circuit board. The conversion circuit modulates the command and sends it to the coupler stator in the form of electromagnetic waves through the coupler rotor on the inner frame. The conversion circuit in the coupler stator demodulates the electromagnetic waves and restores them to the action command. This command is sent to the wireless communication conversion circuit in the middle frame for modulation and is then sent to the coupler stator in the form of electromagnetic waves through the coupler rotor on the middle frame for step-by-step transmission. On the other hand, the command is sent to the interface control circuit board on the inner frame. After receiving the command, the interface control circuit board parses the data and determines whether the command's terminal node is the inner frame. If it is the inner frame, it responds to the command request; otherwise, it does not perform any operation.

[0024] The command is transmitted to the base interface control circuit board in the manner described above. The interface control circuit board parses the data and determines that the command is an action command. Then, it sends the data corresponding to the command to the wireless communication conversion circuit board of the base. The conversion circuit modulates the data and sends it to the coupler rotor in the form of electromagnetic waves through the coupler stator on the base. The data is transmitted to the interface control circuit board of the platform in the opposite direction in the same manner as described in step 1).

[0025] In summary, this completes one command and data exchange process between the platform and the base.

[0026] The platform-type inertial navigation system is a four-axis system, including inertial instruments, a platform body, a frame system, and a stabilization loop. The inertial instruments are mounted on the platform body, which is installed within the frame system. The wireless transmission system is installed within the rotational axis system of the frame system. The frame system consists of an O-shaped frame and corresponding rotational axis systems. A complete four-axis platform-type inertial navigation system consists of four levels of frames and rotational axis systems. From the outside to the inside, the four levels of O-shaped frames are the base, outer frame, middle frame, and inner frame, with corresponding axis systems being the base axis system and the outer frame axis system. The system comprises a middle frame axis system and an inner frame axis system. Each O-shaped frame and its rotation axis form a "Φ" shape, where "O" represents the frame, the vertical bar in the middle is the rotation axis of that frame, and the intersection of the O-shaped frame and the rotation axis is the rotation axis system of that frame. The rotation axis systems of each frame level have the same function: to provide support and transmit motion. That is, the base serves as the outer frame, the outer frame as the middle frame, the middle frame as the inner frame, and the inner frame as the platform body, providing support and transmitting motion. The rotation axis system includes: bearings, a torque motor, an encoder, and a wireless transmission system.

[0027] The wireless transmission system in the rotating axis system is used to transmit electrical energy and communication signals from the outside of the platform inertial navigation system to the platform body, providing electrical energy and control signals to the inertial instruments inside the platform body. The wireless transmission system is divided into a power supply module and a communication module. The power supply module is further divided into a platform body power supply module and a motor power supply module. The platform body power supply module is used to introduce the input voltage from the outside of the platform inertial navigation system, and after inter-stage wireless conversion, provide power to the relevant control board circuits inside the platform body. The motor power supply module is used to provide power to the motor drive and control circuits in the base, outer frame, middle frame, and inner frame axis system, driving the motors, thereby causing the outer frame, middle frame, inner frame, and platform body to rotate around their respective axes. The wireless communication module is used to realize communication between the interface control circuit boards of the base, outer frame, middle frame, inner frame, and platform body.

[0028] The platform power supply module consists of a coupler and a conversion circuit. The coupler is composed of a coupler stator and a coupler rotor. Electrical energy from an external power source is converted into magnetic energy by the conversion circuit on the base and the coupler stator mounted on the base. At the same time, the coupler stator couples the magnetic energy to the coupler rotor through space. The coupler rotor converts the magnetic energy into electrical energy and transmits the electrical energy to the coupler stator mounted on the outer frame. Then, the coupler stator on the outer frame transmits electrical energy to the middle frame in the same way as the base. This process is repeated from the middle frame to the inner frame, and from the inner frame to the platform, realizing the conversion of electrical energy to magnetic energy and magnetic energy to electrical energy step by step. Finally, the external power supply is transmitted to the platform wirelessly.

[0029] The motor power supply module consists of a coupler and a conversion circuit. The coupler is composed of a coupler stator and a coupler rotor. Electrical energy from an external power source is converted into magnetic energy by the conversion circuit on the base and the coupler stator mounted on the base. Simultaneously, the coupler stator couples the magnetic energy to the coupler rotor through space. The coupler rotor converts the magnetic energy into electrical energy. This electrical energy is transmitted to the coupler stator mounted on the outer frame on one hand, and converted into power supply for the outer frame equipment by the conversion circuit on the outer frame on the other hand, thus powering the motor drive and related control circuits of the outer frame. Similar to the wireless power transmission method from the base to the outer frame, electrical energy is converted into magnetic energy and then back to electrical energy step by step from the outer frame to the middle frame and from the middle frame to the inner frame, thus powering the motor drive and related control circuits of each frame.

[0030] The wireless communication module consists of a coupler and a conversion circuit. The coupler consists of a coupler stator and a coupler rotor. The wireless communication module enables communication between the platform interface control circuit board and the interface control circuit boards on the base, outer frame, middle frame, and inner frame. The main control node of the wireless communication system is the platform, and the other frames are the terminal nodes of the communication system.

[0031] The advantages of this invention compared to the prior art are:

[0032] 1) Replacing conductive slip rings with wireless transmission technology can significantly improve the electrical performance and reliability of the system, as the mechanical friction of conductive slip rings may result in poor contact, foreign matter, or even electrical sparks.

[0033] 2) Compared to conductive slip rings, wireless power supply and communication are used. The entire system is designed based on the architecture of wireless communication bus. The interconnection between each frame is only wireless power supply and communication. The devices inside each frame are interconnected by cables, thus reducing the complexity of the internal interconnection of the system. Attached Figure Description

[0034] Figure 1 This is a basic schematic diagram of magnetic induction coupling wireless power transfer.

[0035] Figure 2 This is a simplified diagram of a four-axis platform-type inertial navigation system.

[0036] Figure 3 This is a schematic diagram of the wireless transmission connection relationship of a four-axis platform inertial navigation system. Detailed Implementation

[0037] This invention discloses a platform-type inertial navigation wireless transmission system. The platform-type inertial navigation is a four-axis system, including inertial instruments, a platform body, a frame system, and a stabilization loop. The inertial instruments are mounted on the platform body, which is installed within the frame system. The wireless transmission system is installed within the rotational axis system of the frame system. The frame system consists of an O-shaped frame and corresponding rotational axis systems. A complete four-axis platform-type inertial navigation system consists of four levels of frames and rotational axis systems. From the outside to the inside, the four levels of O-shaped frames are a base, an outer frame, a middle frame, and an inner frame, with their corresponding axis systems being the base... The platform comprises a base shaft system, an outer frame shaft system, a middle frame shaft system, and an inner frame shaft system. Each O-shaped frame and its rotation axis form a "Φ" shape, where "O" represents the frame, the vertical bar in the middle is the rotation axis of that frame, and the intersection of the O-shaped frame and the rotation axis is the rotation shaft system of that frame. The rotation shaft systems of each frame level serve the same function, providing support and transmitting motion. Specifically, the base provides support and transmits motion for the outer frame, the outer frame for the middle frame, the middle frame for the inner frame, and the inner frame for the platform body. The rotation shaft system includes bearings, a torque motor, an encoder, and a wireless transmission system.

[0038] The wireless transmission system in the rotating axis system is used to transmit electrical energy and communication signals from the outside of the platform inertial navigation system to the platform body, providing electrical energy and control signals to the inertial instruments inside the platform body. The wireless transmission system is divided into a power supply module and a communication module. The power supply module is further divided into a platform body power supply module and a motor power supply module. The platform body power supply module is used to introduce the input voltage from the outside of the platform inertial navigation system, and after inter-stage wireless conversion, provide power to the relevant control board circuits inside the platform body. The motor power supply module is used to provide power to the motor drive and control circuits in the base, outer frame, middle frame, and inner frame axis system, driving the motors, thereby causing the outer frame, middle frame, inner frame, and platform body to rotate around their respective axes. The wireless communication module is used to realize communication between the interface control circuit boards of the base, outer frame, middle frame, inner frame, and platform body.

[0039] The electrical characteristics are as follows:

[0040] refer to Figure 3 The entire wireless transmission system is divided into three subsystems. The first part is the wireless power supply path for the platform; the second part is the wireless motor power supply path; and the third part is the wireless communication path. Figure 3 In this system, the input voltage for the "platform wireless power supply path" is introduced from outside the system and, after multi-stage transmission through the wireless power supply coupler, powers the relevant circuits on the platform. The "motor wireless power supply path" transmits the external power supply through the wireless power supply coupler in a hierarchical coupling process, powering the drive motors on the inner, middle, and outer frame axes of the platform-type inertial navigation system, and also providing the necessary power to the interface control circuits on the inner, middle, and outer frames. The "wireless communication path," through multi-stage transmission through the wireless communication coupler, enables communication between the interface control circuit boards located on the platform, inner frame, middle frame, outer frame, and base.

[0041] The wireless transmission method, comprising a wireless communication method and a wireless power supply method, is characterized by comprising:

[0042] Wireless communication methods:

[0043] 1) It adopts near-field wireless communication technology based on amplitude shift keying (ASK), with a carrier frequency band of 100MHz and a pass-through mode for signal transmission to reduce intermediate signal processing steps and thus reduce signal transmission delay. The most representative example is the four-axis platform inertial navigation system (…). Figure 2 For example, refer to Figure 3 The entire wireless communication transmission consists of four levels, namely the base station. Outer frame Mid-frame The transmission process is explained using the inner frame as an example of wireless signal transmission within it. (Appendix) Figure 3 The inner frame interface control circuit board transmits data simultaneously to the inner frame shaft-end circuit and the FPGA on the middle frame shaft-end circuit board via a 485 serial communication bus. The FPGAs on both circuit boards modulate the transmitted data. The inner frame shaft-end antenna transmits the modulated data to the platform, and the middle frame shaft-end antenna transmits the modulated data to the middle frame. The platform and the middle frame shaft-end antenna receive the data. The FPGA on the platform's wireless communication processing circuit board demodulates and restores the received data, and the FPGA on the middle frame shaft-end circuit demodulates and restores the received data. The FPGA on the platform's wireless communication processing circuit board sends the restored data to the platform's interface control board via a 485 bus, and the FPGA on the middle frame shaft-end circuit sends the restored data to the middle frame's interface control board via a 485 bus, while simultaneously sending corresponding data to the outer frame, thus transmitting data step by step.

[0044] 2) Design two-stage filters, high-pass and band-pass, in each stage of the signal transmission channel.

[0045] Wireless power supply method:

[0046] This system employs a four-level wireless power supply transmission method, the transmission principle of each level is as follows: Figure 1 As shown, the externally input DC power supply is converted into an AC signal by a high-frequency inverter. This AC signal is transmitted to the secondary side of the transformer through a loosely coupled transformer (using air as the coupling medium), and then through high-frequency rectification and filtering to restore it to a DC power supply voltage for the load. Simultaneously, this DC voltage serves as the input DC power supply for the next stage of wireless power transmission, continuing to be transmitted internally using the same principle. The most representative example is a four-axis platform inertial navigation system (...). Figure 2 For example, refer to Figure 3The input voltage of the "platform wireless power supply path" is introduced from outside the system and, after being transmitted through multiple stages by the wireless power supply coupler, powers the relevant circuits of the platform. The "motor wireless power supply path" transmits the external power supply through the wireless power supply coupler in stages, powering the drive motors on the shaft ends of the inner, middle, and outer frames of the platform-type inertial navigation system, and also providing the necessary power to the interface control circuits on the inner, middle, and outer frames. To improve the wireless power transmission efficiency, a comprehensive design is required, considering factors such as the selection of magnetic materials, excitation wire diameter, and ampere-turn ratio of the coupler. A multi-objective optimization algorithm is then used to iteratively optimize key parameters such as the self-inductance, mutual inductance, and current of the coupler.

[0047] The technologies involved in the platform-based inertial navigation wireless transmission system and method can be applied to devices or systems with rotation mechanisms, as well as various single-axis, dual-axis, three-axis or multi-axis turntables.

[0048] The following description, in conjunction with the accompanying drawings, provides a more detailed account of a platform-based inertial navigation wireless transmission system and method provided in this application. Specific implementation methods may include (e.g.) Figures 1-3 As shown):

[0049] Due to the complexity and numerous constraints of platform-based inertial navigation systems, replacing conductive slip rings with wireless transmission technology is challenging. To enable the application of wireless transmission technology in platform-based inertial navigation systems, the following four requirements must be met for wireless communication: a. Good real-time signal transmission, high transmission rate, and high reliability; b. Maximum signal delay after multi-stage transmission not exceeding 5µs; c. No interference to the system's internal or external systems, meeting electromagnetic compatibility requirements; d. Sufficiently small structural size and weight to meet system requirements and facilitate maintenance. For wireless power supply transmission, the following four requirements must be met: a. Single-stage transmission efficiency not less than 90%, reducing the power consumption of the wireless transmission system itself; b. After multi-stage transmission, the power supply requirements for each stage of the system must be met; c. No interference to the system's internal or external systems, meeting electromagnetic compatibility requirements; d. Sufficiently small structural size and weight to meet system requirements and facilitate maintenance.

[0050] In order to use wireless transmission technology in platform-based inertial navigation and meet the above requirements, it is necessary to comprehensively consider the selection of wireless transmission scheme, system electrical function design and system structure design.

[0051] Wireless transmission solution selection:

[0052] For wireless communication, to meet the requirements of platform-based inertial navigation for signal transmission delay and structural size, near-field wireless communication technology based on amplitude shift keying (ASK) was adopted. ASK-based communication technology has fewer intermediate links and smaller structural units, effectively balancing low latency and structural requirements. The ASK transmission distance is almost entirely confined within the coupling body, unaffected by external interference, resulting in higher security and anti-interference capabilities. For wireless power transmission, a magnetic field near-field coupling method is used, ensuring that power transmission is limited to the coupling space and preventing outward leakage.

[0053] For wireless power supply, a loosely coupled solution based on air medium was adopted. At the same time, measures such as canned magnetic cores and reducing the transmission distance of the coupling mechanism were used to optimize the magnetic circuit design, reduce magnetic field loss, increase mutual inductance, and improve the efficiency of wireless power supply transmission at each stage.

[0054] System electrical function design:

[0055] Because the wireless power transmission coil and wireless communication coil are coaxially integrated, energy is coupled into the communication coil during power transmission, interfering with the communication signal and thus limiting the increase in wireless communication speed. To reduce the interference of the power transmission channel on the signal channel and achieve a wireless communication speed of 5Mbps, this solution comprehensively designs the spatial location of the wireless power transmission coil and communication coil, the carrier frequency band, the filtering structure, and the detection circuit. Specific details are as follows:

[0056] 1) By reducing the distance between the receiving (coupler rotor) and transmitting (coupler stator) coils used for signal transmission to between 0.4mm and 0.5mm, the influence of the magnetic field energy of the power coil on the signal coil is reduced, while ensuring a certain reliable movement gap between the transmitting and receiving coils.

[0057] 2) By increasing the carrier frequency band for wireless signal transmission to 100MHz, the frequency rejection ratio is increased, thereby improving the communication rate.

[0058] 3) By designing a two-stage filter structure of high-pass and band-pass filters in the signal transmission channel, low-frequency electrical noise can be further filtered out.

[0059] 4) Improve the detection circuit to adapt to the 5Mbps transmission rate and further enhance the demodulation capability of high-speed signals.

[0060] To achieve a signal delay of no more than 5μs, a transparent transmission mode is selected for wireless communication. This is exemplified by the most representative quadcopter platform inertial navigation system (PCI). Figure 2 For example, refer to Figure 3 The entire wireless communication transmission consists of four levels, namely... The transmission process is explained using the wireless signal transmission within the inner frame as an example. Figure 3 The inner frame interface control circuit board transmits data simultaneously to the inner frame shaft-end circuit and the FPGA on the middle frame shaft-end circuit board via a 485 serial communication bus. The FPGAs on both circuit boards modulate the transmitted data. The inner frame shaft-end antenna transmits the modulated data to the platform, and the middle frame shaft-end antenna transmits the modulated data to the middle frame. The platform and the middle frame shaft-end antenna receive the data. The FPGA on the platform's wireless communication processing circuit board demodulates and restores the received data, and the FPGA on the middle frame shaft-end circuit demodulates and restores the received data. The FPGA on the platform's wireless communication processing circuit board sends the restored data to the platform's interface control board via a 485 bus, and the FPGA on the middle frame shaft-end circuit sends the restored data to the middle frame's interface control board via a 485 bus, while simultaneously sending corresponding data to the outer frame, thus transmitting data step by step.

[0061] The entire data transmission process described above does not involve any auxiliary verification or automatic retransmission mechanisms, reducing the latency overhead caused by intermediate processing such as framing, deframing, verification, and retransmission in other wireless communication methods. The latency of the entire data transmission only comes from the signal modulation and demodulation process, thus ensuring the minimization of signal transmission latency.

[0062] like Figure 3 The entire wireless transmission system is divided into three subsystems. The first part is the wireless power supply path for the platform; the second part is the wireless motor power supply path; and the third part is the wireless communication path. Figure 3 In the system, the input voltage of the "platform wireless power supply path" is introduced from outside the system and, after multi-stage transmission through wireless power couplers, powers the relevant circuits of the platform. The "motor wireless power supply path" transmits the external power supply through a series of wireless power couplers to power the drive motors on the shaft ends of the inner frame 4, middle frame 3, and outer frame 2 in the platform-type inertial navigation system, and also provides the necessary power to the interface control circuits on the inner frame 4, middle frame 3, and outer frame 2. The "wireless communication path" enables communication between the interface control circuit boards located in the platform 5, inner frame 4, middle frame 3, outer frame 2, and base 1 through multi-stage transmission through wireless communication couplers.

[0063] The specific implementation method of this invention is as follows:

[0064] A platform-type inertial navigation system (INS) mainly consists of inertial instruments (gyroscopes and accelerometers), related circuits (including a computer, power supply, etc.), a platform body, a frame system, and a stabilization loop. The inertial instruments are mounted on the platform body, and bearings, torque motors, encoders, and conductive slip rings are installed at the ends of each frame axis. The conductive slip rings are used to achieve communication and power transmission between the frames. For a platform-type INS operating in inertial space stabilization mode, its working principle is to use the gyroscopes mounted on the platform body to sense the angular motion information of the carrier relative to inertial space as feedback signals to the platform servo controller. The controller receives the gyroscope feedback signals and generates control outputs, driving the frame axes to produce motion opposite to the angular motion direction of the carrier, thereby maintaining the platform's orientation relative to inertial space (maintaining inertial space stability). Using the encoder outputs at the ends of each frame axis, the carrier's attitude angle information relative to inertial space can be obtained after a certain coordinate transformation. By integrating the accelerometer measurements after considering the effects of gravity, the carrier's real-time velocity and position information can be obtained.

[0065] Platform-based inertial navigation systems include three-axis or four-axis systems. A four-axis system is simply a three-axis system with an additional frame added outside the outer frame. (See reference for a four-axis platform-based inertial navigation system.) Figure 2 As shown, the system structure mainly consists of a platform body 5, an inner frame 4, a middle frame 3, an outer frame 2, and a base 1. Divided by the frame axis, the entire system is divided into five parts from the inside out: platform body 5, inner frame 4, middle frame 3, outer frame 2, and base 1. Platform body 5 houses inertial instruments (gyroscope and accelerometer) and their conversion circuits, a DSP signal processing board, a secondary power supply board, and a temperature control circuit board. The inner frame 4, middle frame 3, outer frame 2, and base 1 are similarly composed, each housing an interface control circuit board, a motor control board, a wireless communication processing board, and a wireless motor power supply interface circuit board. Each rotating frame's shaft end is equipped with four components: a bearing, a brushless torque motor, an encoder, and a shaft-end coupling circuit for wireless power transmission and communication.

[0066] Taking the most representative quadcopter platform inertial navigation system as an example, refer to Figure 3 The wireless transmission system for platform-type inertial navigation involved in this invention consists of three parts: a wireless communication path, a wireless power supply path for the platform, and a wireless power supply path for the motor.

[0067] 1) Wireless communication path: It consists of four similar wireless communication circuits. Taking the wireless communication in the inner frame as an example, the composition of each wireless communication circuit is explained.

[0068] a. Wireless communication processing circuit board: used for forwarding digital communication signals;

[0069] b. Stator shaft end circuit: It consists of an FPGA signal modulation and demodulation circuit and a communication signal coupler, and is used to send wireless communication data to the stage or receive wireless communication data from the stage;

[0070] c. Rotor shaft end circuit: Composed of FPGA signal modulation and demodulation circuit and communication signal coupler, used to send wireless communication data to the middle frame or receive wireless communication data from the middle frame.

[0071] 2) Wireless power supply path of the platform: It consists of a wireless power supply processing circuit board located on the base, four-level power couplers located in each frame, and a wireless power supply circuit board located on the platform; the function of the whole device is to provide power to the equipment on the platform through wireless coupling.

[0072] 3) Wireless power supply path for motors: It consists of a wireless motor power supply processing circuit board located on the base, and power couplers and their wireless motor power supply processing circuit boards located in each frame; the function of the whole device is to provide power to the devices located in the inner frame, middle frame and outer frame in a wireless coupling manner.

[0073] For wireless communication, to meet the requirements of platform-based inertial navigation for signal transmission delay and structural size, near-field wireless communication technology based on amplitude shift keying (ASK) was adopted. ASK-based communication technology has fewer intermediate links and smaller structural units, effectively balancing low latency and structural requirements. The ASK transmission distance can be almost entirely confined within the coupling body, unaffected by external interference, resulting in higher security and anti-interference capabilities. For wireless power transmission, a magnetic field near-field coupling method is used, ensuring that power transmission is limited to the coupling space and preventing outward leakage.

[0074] Because the wireless power transmission coil and wireless communication coil are coaxially integrated, energy is coupled into the communication coil during power transmission, interfering with the communication signal and thus limiting the increase in wireless communication speed. To reduce the interference of the power transmission channel on the signal channel and achieve a wireless communication speed of 5Mbps, this solution comprehensively designs the spatial location of the wireless power transmission coil and communication coil, the carrier frequency band, the filtering structure, and the detection circuit. Specific details are as follows:

[0075] 1) By reducing the distance between the receiving and transmitting coils used for signal transmission to

[0076] The gap is between 0.4mm and 0.5mm, which reduces the influence of the magnetic field energy of the power coil on the signal coil, while ensuring a certain reliable movement gap between the transmitting and receiving coils.

[0077] 2) By increasing the carrier frequency band for wireless signal transmission to 100MHz, the frequency rejection ratio is increased, thereby improving the communication rate.

[0078] 3) By designing a two-stage filter structure of high-pass and band-pass filters in the signal transmission channel, low-frequency electrical noise can be further filtered out.

[0079] 4) Improve the detection circuit to adapt to the 5Mbps transmission rate and further enhance the demodulation capability of high-speed signals.

[0080] To ensure a signal delay of no more than 5μs, transparent transmission mode is selected for wireless communication. (See attached reference.) Figure 3 The entire wireless communication transmission consists of four levels, namely... The transmission process is explained using the wireless signal transmission within the inner frame as an example. (See attached image.) Figure 3 The inner frame interface control circuit board transmits data simultaneously to the inner frame shaft-end circuit and the FPGA on the middle frame shaft-end circuit board via a 485 serial communication bus. The FPGAs on both circuit boards modulate the transmitted data. The inner frame shaft-end antenna transmits the modulated data to the platform, and the middle frame shaft-end antenna transmits the modulated data to the middle frame. The platform and the middle frame shaft-end antenna receive the data. The FPGA on the platform's wireless communication processing circuit board demodulates and restores the received data, and the FPGA on the middle frame shaft-end circuit demodulates and restores the received data. The FPGA on the platform's wireless communication processing circuit board sends the restored data to the platform's interface control board via a 485 bus, and the FPGA on the middle frame shaft-end circuit sends the restored data to the middle frame's interface control board via a 485 bus, while simultaneously sending corresponding data to the outer frame, thus transmitting data step by step.

[0081] The entire data transmission process described above does not involve any auxiliary verification or automatic retransmission mechanisms, reducing the latency overhead caused by intermediate processing such as framing, deframing, verification, and retransmission in other wireless communication methods. The latency of the entire data transmission only comes from the signal modulation and demodulation process, thus ensuring the minimization of signal transmission latency.

[0082] The input voltage for the "platform wireless power supply path" is introduced from outside the system and, after multi-stage transmission via wireless power couplers, powers the relevant circuits of the platform. The "motor wireless power supply path" transmits the external power supply through a hierarchical coupling process via wireless power couplers to power the drive motors on the inner, middle, and outer frame axes of the platform-type inertial navigation system, and also provides the necessary power to the interface control circuits on the inner, middle, and outer frames. The "wireless communication path," through multi-stage transmission via wireless communication couplers, enables communication between the interface control circuit boards located on the platform, inner frame, middle frame, outer frame, and base.

[0083] To achieve a single-stage conversion efficiency of at least 90% for wireless power transmission, a comprehensive design is required, considering factors such as the selection of magnetic materials for the coupler, the excitation wire diameter, and the ampere-turn ratio. A multi-objective optimization algorithm is employed to iteratively optimize key parameters of the coupler, including self-inductance, mutual inductance, and current. This increases the mutual inductance while reducing self-inductance and current, thereby improving the coupler's transmission efficiency and reducing heat generation while meeting power transmission requirements, significantly enhancing the coupler's energy efficiency characteristics. To reduce the system temperature gradient, heat dissipation metal plates are used to conduct the heat loss from the power modules and high-power transistors on the circuit board to the equipment housing for heat dissipation.

[0084] In terms of structural design, to enable the application of wireless transmission technology in platform-type inertial navigation, the following design requirements must be met: a. The shaft-end components, bearings, torque motors, encoders, and wireless transmission systems in each frame axis system consist of two parts: a stator and a rotor. The stator and rotor are respectively installed at the shaft ends of two adjacent frames. That is, if the stator is installed on the base, its rotor is installed on the outer frame; if the stator is installed on the outer frame, its rotor is installed on the middle frame; if the stator is installed on the middle frame, its rotor is installed on the inner frame; and if the stator is installed on the inner frame, its rotor is installed inside the platform body; b. The coupling induction surfaces of the stator and rotor must be installed relative to each other, maintaining a gap of 0.2–0.5 mm; c. There is relative motion between the rotor and stator, and the rotor can rotate around the rotation axis of the rotating frame axis system; d. Under the premise of meeting performance requirements, the size, inertia, and weight should be small; e. Electromagnetic interference between the shaft-end components should be small.

[0085] To meet the aforementioned structural design requirements, the following methods were adopted: a. Shaft-free design: The shaft ends of each frame shaft system for installing the wireless transmission system were designed to be shaft-free. Currently, in the platform-type inertial navigation system, the rotors of each component in the frame shaft system are installed and fixed on shaft parts, and each rotor is fixed on the shaft with parts such as pressure plates and shaft end nuts. After shaft-free design, not only is the installation and fixation of the wireless transmission system coupler solved, but also provides a guarantee for the lightweight and compact design of the platform inertial navigation system; b. Bearing with built-in mounting flange: Flanges are extended on the static and dynamic end faces of the bearing. The bearing flanges replace the traditional shaft parts and accessories to realize the installation and fixation of all components in the shaft system, thus realizing the shaft-free design mentioned above; c. Threaded holes are opened on the end faces of the static and dynamic rings of the bearing to realize the installation and fixation of all shaft end components, including the wireless transmission system coupler; d. The method of integrating parts into one is adopted to integrate the platform power supply coupling module, communication module coupler, and communication path circuit board (referred to as "two parts and one board") into one unit, which solves the problem of installing three wireless transmission system modules on two shaft ends of each shaft system.

[0086] Furthermore, the wireless power transmission coupler employs a can-shaped magnetic core to enclose the coil, except for the energy transmission surface, thereby focusing the magnetic field lines along the transmission path. This significantly reduces leakage into the surrounding space, thus minimizing absorption of the magnetic field lines by surrounding metal and achieving decoupling between the coupler and the surrounding metal. Simultaneously, techniques such as reducing the coupler's transmission distance are used to optimize the magnetic circuit design. With these measures, the wireless power coupler can concentrate most of the magnetic field lines on the power transmission channel, effectively reducing electromagnetic radiation from the coupler's magnetic field to surrounding equipment and suppressing the influence of surrounding metal on energy and signal transmission modules.

[0087] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A platform inertial navigation wireless transmission system, characterized in that, The platform type inertial navigation system is a four-axis system, comprising an inertial instrument, a platform body, a frame system and a stable loop; the inertial instrument is installed on the platform body, and the platform body is installed in the frame system; the wireless transmission system is installed in the rotating shaft system of the frame system; the frame system is composed of an Ο-shaped frame and a corresponding rotating shaft system; a set of four-axis platform type inertial navigation system is composed of a four-stage frame and a rotating shaft system; from the outside to the inside, the four-stage Ο-shaped frame is a base, an outer frame, a middle frame and an inner frame, and the corresponding shaft system is a base shaft system, an outer frame shaft system, a middle frame shaft system and an inner frame shaft system; each stage of the Ο-shaped frame and its rotating shaft line form a "Φ" character, wherein the "Ο" is the frame, the vertical bar in the middle is the rotating shaft line of the frame, and the intersection of the Ο-shaped frame and the rotating shaft line is the rotating shaft system of the frame; the rotating shaft systems of the frames at all stages have the same effect and are used to provide support and transfer motion, i.e. the base, the outer frame, the middle frame and the inner frame provide support and transfer motion for the platform body; the rotating shaft system comprises a bearing, a torque motor, a code disc and a wireless transmission system; The wireless transmission system in the rotating shaft system is used to transmit electric energy and communication signals from the outside of the platform inertial navigation system to the platform body, so as to provide electric energy and control signals for the inertial instrument inside the platform body; the wireless transmission system is divided into a power supply module and a communication module, wherein the power supply module is further divided into a body power supply module and a motor power supply module; the body power supply module is used to introduce the input voltage from the outside of the platform inertial navigation system, and convert the voltage wirelessly between stages to provide electric energy for the related control board circuit inside the platform body; the motor power supply module is used to provide electric energy for the motor driving and control circuit in the shaft system of the base, the outer frame, the middle frame and the inner frame, drive the motor, and thus make the outer frame, the middle frame, the inner frame and the platform body rotate around their respective shaft lines; the wireless communication module is used to realize communication between the interface control circuit boards of the base, the outer frame, the middle frame, the inner frame and the platform body.

2. The platform inertial navigation wireless transmission system according to claim 1, wherein, The body power supply module is composed of a coupling body and a conversion circuit, and the coupling body is composed of a coupling body stator and a coupling body rotor; the electric energy from the external power source is converted into magnetic energy by the conversion circuit on the base and the coupling body stator installed on the base, at the same time, the coupling body stator couples the magnetic energy to the coupling body rotor through space, the coupling body rotor converts the magnetic energy into electric energy, and transmits the electric energy to the coupling body stator installed on the outer frame; then the coupling body stator on the outer frame transmits electric energy to the middle frame in the same way as the base, and the conversion of electric energy to magnetic energy and magnetic energy to electric energy is realized step by step from the outer frame to the middle frame, the middle frame to the inner frame and the inner frame to the platform body, and finally the external power supply is transmitted to the platform body by a wireless method.

3. The platform inertial navigation wireless transmission system according to claim 1, wherein, The motor power supply module is composed of a coupling body and a conversion circuit, and the coupling body is composed of a coupling body stator and a coupling body rotor. The electric energy from an external power source is converted into magnetic energy by the conversion circuit on the base and the coupling body stator installed on the base, and the coupling body stator couples the magnetic energy to the coupling body rotor through space, and the coupling body rotor converts the magnetic energy into electric energy, which is transmitted to the coupling body stator installed on the outer frame, and the conversion circuit on the outer frame converts the electric energy into a power supply for the outer frame motor drive and related control circuit; the wireless power transmission mode from the base to the outer frame is the same, and the electric energy is transmitted from the outer frame to the middle frame, and the middle frame to the inner frame, to realize the conversion of electric energy to magnetic energy and magnetic energy to electric energy, and to realize the power supply for the motor drive and related control circuit of each frame.

4. The platform inertial navigation wireless transmission system according to claim 1, wherein, The wireless communication module is composed of a coupling body and a conversion circuit, and the coupling body is composed of a coupling body stator and a coupling body rotor. The wireless communication module realizes the communication between the interface control circuit board of the base, the outer frame, the middle frame and the inner frame. The main control node of the wireless communication system is the base, and the other frames are terminal nodes of the communication system.

5. The platform inertial navigation wireless transmission system according to claim 4, characterized in that, The command data interaction process of the wireless communication module is as follows: 1) The base sends the read action instruction command to the wireless communication conversion circuit board of the base, the conversion circuit modulates the command, and sends it to the coupling body stator in the form of electromagnetic wave through the coupling body rotor on the inner frame, and the conversion circuit of the coupling body stator part demodulates the electromagnetic wave to restore the action instruction command, which is sent to the wireless communication conversion circuit of the middle frame, modulated and sent to the coupling body stator in the form of electromagnetic wave through the coupling body rotor on the middle frame, and transmitted step by step; on the other hand, the command is sent to the interface control circuit board on the inner frame, and the interface control circuit board analyzes the data after receiving the command, judges whether the terminal node of the command is the inner frame, and if it is the inner frame, it responds to the command requirement, if it is not the inner frame, it does not work; 2) The command is transmitted to the interface control circuit board of the base in the above manner, the interface control circuit board analyzes the data, judges that the command is an action instruction command, and sends the corresponding data of the command to the wireless communication conversion circuit board of the base, the conversion circuit modulates the data, and sends it to the coupling body rotor in the form of electromagnetic wave through the coupling body stator on the base, and the data is transmitted to the interface control circuit board of the base in the same way as described in step 1) in the opposite direction; 3) The above completes the command data interaction process between the base and the base.

6. A platform inertial navigation wireless transmission system according to any one of claims 1-5, characterized in that, The communication module, the table body power supply module and the motor power supply module in the wireless transmission system are installed in two shaft ends of each frame shafting, and the shaft ends of each frame shafting are de-axled, that is, mounting flanges and mounting holes are designed on the static ring and the dynamic ring of the bearing, and the mounting and fixing of the bearing are realized without shaft parts; meanwhile, the torque motor, the code disc, the stator and the rotor of each coupling of the wireless transmission system are designed in a high integration and integration, and the mounting and fixing of all parts of the shaft end are realized, and the light and small design of the whole machine is ensured.

7. A platform inertial navigation wireless transmission method based on the system of any one of claims 1-6, characterized in that, Comprise: 1) The table body sends the read action instruction command to the wireless communication conversion circuit board of the table body, the conversion circuit modulates the command, sends the command to the coupling stator in the form of electromagnetic wave through the coupling rotor on the inner frame, the conversion circuit of the coupling stator part demodulates the electromagnetic wave and restores it to the action instruction command, the command is sent to the wireless communication conversion circuit of the middle frame, the command is modulated, and is sent to the coupling stator in the form of electromagnetic wave through the coupling rotor on the middle frame, and is transmitted step by step; on the other hand, the command is sent to the interface control circuit board on the inner frame, the interface control circuit board analyzes the data after receiving the command, judges whether the terminal node of the command is the inner frame, if it is the inner frame, it responds to the command requirement, if it is not the inner frame, it does not work; 2) The command is transmitted to the base interface control circuit board in the above manner, the interface control circuit board analyzes the data, judges that the command is an action instruction command, and sends the data corresponding to the command to the wireless communication conversion circuit board of the base, the conversion circuit modulates the data, sends the data to the coupling rotor through the coupling stator on the base in the form of electromagnetic wave, and the data is transmitted to the interface control circuit board of the table body in the reverse direction of step 1); 3) The above completes the command data interaction process between the table body and the base.

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