Design And Research Of Wireless Power Supply System For Capsule Diagnostic Robot

When the capsule diagnostic robot is used for the diagnosis of the human gastrointestinal tract,the battery power supply has the disadvantage of limited capacity and unable to diagnose for a long time.With the capsule diagnostic robot equipped with high frame rate and highresolution cameras and the addition of diagnosis and treatment function modules,the problem of power supply has become a bottleneck restricting the application of capsule diagnostic robots.The weakly coupled wireless power supply technology provides a feasible way to solve this bottleneck problem.Based on this,this study was funded by the National Natural Science Foundation of China（No.61803347）.The design and research of the wireless power supply system for the capsule diagnostic robot was carried out.In order to realize the wireless power supply of the capsule diagnostic robot and the miniaturization of the diagnostic robot,a new wireless power supply method is proposed in this paper.According to the real-time detection results of the attitude for the one-dimensional receiving coil installed in the capsule,the intensity and direction of the alternating magnetic field excited by the external transmitting coil are regulated to keep the output power of the onedimensional receiving coil stable.A wireless power supply system based on "rotating twodimensional transmitting coil + one-dimensional receiving coil + airborne attitude detection" was developed.In the capsule,STM32F103TBU6 is used as the main control chip to realize the data collection,processing and transmission of the electromotive force of the receiving coil and the movement attitude of the capsule.The motion attitude detection of the capsule is realized by the six-axis motion sensor MPU6050.The real-time attitude detection calculation model of the one-dimensional receiving coil in the alternating magnetic field environment is established.And the motion attitude of the capsule is obtained based on the fusion calculation of the motion sensor data and the receiving coil electromotive force.The CC1101 is used to realize the wireless transmission of data with the external receiving system,and the communication between the data receiving system and the main control platform is realized through the serial port,to realize the real-time processing and display of the data.In terms of receiving coil design,the design optimization is carried out under the condition of limited space constraints and power transmission efficiency,including the design of the receiving coil structure and magnetic core.In the design of the external transmitting coil system,the theoretical system of wireless power transmission has been improved,the resonant coupling circuit model of the wireless power transmission has been determined,and the calculation model of the magnetic induction intensity of the magnetic field for the two-dimensional transmission coil has been completed.A technology for controlling the intensity and direction of the alternating magnetic field excited by the transmitting coil is proposed.The full-bridge inverter circuit is used to invert and control the frequency of the DC power supply.Combined with the movement attitude of the capsule,a two-dimensional orthogonal coil and the stepper motor drive device are used to control the intensity and direction of the alternating magnetic field excited by the transmitting coil.In this paper,an attitude detection capsule and the wireless power supply system are developed.The size of the attitude detection capsule is Φ27mm×12mm.Experiments have been developed for capsule position detection and wireless power supply,and the operation and stability of the system has been verified.The experimental results show that the system can accurately realize the expected functions,the deviation of the attitude angle is less than 5degrees,and the received power exceeds 500 m W during the whole working process,which meets the working requirements of the capsule diagnostic robot.When the attitude of the receiving coil changes suddenly,the load working voltage of the receiving coil produces the voltage drop of about 0.3V at the maximum,and returns to a stable value after about 0.6s.The steady-state deviation of the induced electromotive force before and after the attitude mutation is about 10%.