| In the field of measurement,unmanned aerial vehicles(UAVs)are increasingly used as vehicles for measurement sensors because of their strong mobility to achieve more flexible measurement.In order to increase the measurement dimension and reduce the measurement dead Angle,the UAV equipped with a robotic arm can increase the degree of freedom of its measurement and achieve a more comprehensive measurement effect.UAVs carrying sensors can achieve a better local measurement function,but for large components,conventional measurement methods are difficult to achieve.Laser tracking measuring system is a kind of high-precision large-size measuring instrument in industrial measuring system.It has the characteristics of high precision,high efficiency,real-time tracking measurement,quick installation,easy operation and so on.It is suitable for large size workpiece assembly measurement,but for the target placement,if the manual touch,for large component measurement will be very inconvenient.If the robot is equipped with the laser tracker target,the advantages of the two can be combined,and the geometric precision measurement of large components can be realized in the manufacturing and assembly production line of large equipment,such as aircraft and ships,etc.According to the above background,this paper designs an aerial measurement robot system based on laser tracker.Set up four rotor carrying more degrees of freedom mechanical arm at the end of the UAV model,in order to reduce the effects of mechanical arm move for unmanned aerial vehicle,set the uav attitude control system design,after the completion of uav attitude control based on the building indoor environment GPS the effect not beautiful,studied the UAV indoor navigation.Finally,a laser tracker target is mounted at the end of the manipulator to realize the measurement function of the aerial manipulator with multiple degrees of freedom.Firstly,the kinematics and dynamics model of the four-rotor UAV with four inputs and six outputs and the measurement model of the manipulator with two degrees of freedom are established.Due to the coupling between the robot arm and the UAV body,it will bring extra interference to the UAV.For the traditional PID control depends on the problem of control model,based on the PID control to compensate,design the intelligent control based on fuzzy neural network compensator,through self setting adaptive neural network parameters for mechanical arm shaking interference to realize compensation for UAV,improve the stability and robustness of the drones.After the attitude control of UAV,aiming at the poor GPS signal in indoor measurement environment,a combination of inertial positioning and visual positioning VIO is proposed to realize the indoor positioning function of UAV.Simple inertial navigation IMU data generates a large amount of summary drift over time,which can be corrected by infrequent updates of visual odometers.The integration of visual and inertial components will greatly improve the accuracy and stability of positioning.The hardware T265 camera is used to realize the indoor stable fixed-point positioning flight of the UAV based on Raspberry Pi as the onboard computer and Pixhawk 2.4.8 as the flight control.Using Raspberry Pi as the control center of aerial robot measurement system,the hardware system of aerial robot based on laser tracker is built.The Raspberry Pi acts as an onboard computer to control the drone and a robotic arm.The UAV adopts Pixhawk 2.4.8 as the flight control hardware,and uses the T265 tracking camera to achieve indoor positioning of the UAV.In the manipulator,bus steering gear and STM32 chip drive are adopted,and TTL is converted to USB through CH340 chip,so that it can connect with Raspberry Pi to realize data communication.Both the drone and the robotic arm operate under the Raspberry Pi’s Robot Operating System.A laser tracker target is mounted at the end of the manipulator to realize the end position data transmission and the measurement function of high degree of freedom. |
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