Design Of Nuclear Power Inspection Robot And Research On Its Vibration Reduction Characteristics

Human beings have created various power generation methods in order to obtain electric energy.Using the huge energy generated by nuclear fusion and nuclear fission to generate electricity is the main power generation method in countries around the world today.However,this method of power generation is very dangerous.The nuclear power plant has strong radiation,which is extremely harmful to the human body.Nuclear power plants have a large amount of inspection work to complete to ensure the normal operation of the instrument and clean the environment.Therefore,inspection robots are widely and extensively used to replace humans to perform inspections in nuclear power plants.This project was sourced from the Development Fund of Harbin Engineering University School of Mechanical and Electrical Engineering(Code: 002070300147).This paper mainly develops an inspection robot for nuclear power plant buildings to detect the temperature、humidity and other indicators in nuclear power plants,as well as manipulator operations and analyzes the vibration reduction characteristics of inspection robots.Firstly,according to the design index,this paper constructs the overall design scheme of the inspection robot.Under the guidance of the overall plan,combined with the existing technology,the walking mechanism 、 vibration-damping suspension mechanism 、 lifting mechanism、operating mechanism and box of the inspection robot were designed respectively.Then,the characteristics of the displacement and acceleration amplitude of the longitudinal vibration caused by the walking process of the inspection robot are analyzed theoretically,which mainly includes:1)The excitation model of vibration caused by walking of the inspection robot was established by using Hertz theory and the roller machining error curve theory of the Mecanum wheel.2)The single degree of freedom vibration model of the inspection robot was established and the natural frequency and stiffness of the single degree of freedom vibration model were derived by using the wave theory,and the change law of the displacement and acceleration response of the model under the above excitation was deduced.3)The specific response forms of the beat vibration and resonance of the single degree of freedom vibration are analyzed,which proves that the inspection robot will not have resonance and beat vibration,which provides a good structural basis for the subsequent motion control of the inspection robot.Secondly,through the static analysis module and modal analysis module of ANSYS Workbench,the structure static analysis and modal analysis of the inspection robot’s box、lower bearing plate、motor bracket、spring and other structures are carried out;The motion of the inspection robot is simulated using ADAMS,and the maximum amplitude of the longitudinal acceleration during the walking of the inspection robot is studied.Then the result of vibration acceleration response derived in Chapter 2 were compared with each other and the reasons for the errors were analyzed.At the same time,the magnitude of the longitudinal acceleration amplitude caused by the load at different positions of the inspection robot was simulated using ADAMS,and the law of the influence of the load on the longitudinal acceleration amplitude of the inspection robot were obtained,which has laid a foundation for the smooth operation of the inspection robot.Thirdly,a three-layer control system with the upper computer control layer、the main control layer and the execution layer is built,and the main hardware is selected,in the meantime the communication method、power supply method and control method of the upper computer are determined;The transfer function model of the stepping motor is deduced,and the relationship between the position error of the lifting lead screw,the motor speed and the encoder is analyzed;The step response of stepping motor under the common PID、BP-PID and fuzzy PID control algorithm is analyzed,and the anti-interference ability of several algorithms is tested by random interference function;The fuzzy PID control strategy is adopted in the walking mechanism and the speed loop of the lifting mechanism,while the common open-loop PID control strategy is adopted in the operating mechanism.Finally,the fuzzy PID algorithm is used to control the stepping motor by MDK keil programming,and then the Lab VIEW is used as the upper computer to carry out the end positioning experiment of the manipulator control strategy,which verifies that the positioning control accuracy of the operating mechanism meets the requirements;The acceleration amplitude of the inspection robot was measured by using the control box to control the movement of the robot,which verified the effectiveness of the damping suspension mechanism and was compared with the result of theoretical and simulation analysis,then analyzed the cause of error.