Research On The Multi-mode Jumping Actuator Design And Attitude Control Of High-efficiency Jumping Robot

Jumping robot has simple and reliable structure,good maneuverability,and can easily cross obstacles several times larger than itself.Therefore,jumping robot has a wider range of activities and better environmental adaptability,thus it is more suitable for applications such as investigation,detection,and rescue.Most research on jumping robots at home and abroad mainly focused on terrestrial jumping robots,while the research on multi-mode and high-efficiency jumping robot which has both aquatic and terrestrial jumping abilities are still research blank in the current international field of mobile robots.Therefore,the research work in this thesis includes the terresitrial jumping actuator design,aquatic water jet thruster design,aerial attitude control,jumping trajectory optimization for obstacle-crossing tasks,multi-mode jumping actuator design,amphibious jumping robot design and experimental verification of the amphibious jumping robot.Based on the current situation of poor payload capability,low energy density and low reliability of the existing terrestrial jumping acutators,an explosive terrestrial jumping scheme was proposed.The propane/nitrous oxide mixed gas was selected as the propellant by comparative analysis,and the chemical characteristics of the selected mixed gas,such as the stoichiometric concentration and limit concentration,were discussed.The structure design of the terrestrial jumping actuator and its typical working process were demonstrated,and the mathematical model of jumping height was established.The jumping actuator’s high-effciency jumping ability was verified through the jumping experiment of jumping actuator with payload and the free jumping experiment of the jumping robot.In order to enable the jumping robot to perform aquatic jumping tasks,a high-pressure water jet thruster scheme using liquid nitrogen/water as propellant combination was proposed.The structure design and typical working process of the water jet thruster were explained.A general mathematical model of jumping height of the water jet thruster was established,and the working parameter of the thruster was optimized according to this model.For the liquid nitrogen self-pressurization process and the high-pressure water-jetting process of the water jet thruster,the respective pressure nephogram and phase nephogram were analyzed through CFD simulation.The aquatic free jumping experiment and terrestrial free jumping experiment of the water jet thruster verified its amphibious characteristic and high-efficiency jumping ability.In terms of the problem of jumping robot’s landing safety,a motion capture system was used to track and photograph the jumping process of biological frog,so as to analyze the mechanism and characteristics of the adjustment of the body posture by swing of its hind legs.Two different attitude control strategies for jumping robot in the flight phase of the jumping process were proposed,and the corresponding mathematical model of the aerial attitude control strategies were established.By result comparisons of UG motion simulation and theoretical model,the accuracy of the first attitude control mathematical model and the effectiveness of the aerial attitude control strategy that robot swings its left and right legs twice in order were verified.For improving the performance of jumping robot’s general obstacle-crossing ability,an optimization method for jumping and obstacle-crossing trajectory was proposed.The theoretical judgment conditions that the robot can overcome different types of obstacles were analyzed,then the theoretical set of jumping trajectories for overcoming obstacles according to the judgment conditions can be generated.An improved whale optimization algorithm(MWOA)was proposed based on the standard whale optimization algorithm,and the optimization performance of the improved algorithm was verified through comparison and analysis.An objective function which evaluates the performace of robot’s jumping and obstacle-crossing trajectorty was proposed,and the jumping trajectory was optimized by the improved whale optimization algorithm,so as to obtain the theoretical jumping trajectory that makes the robot’s obstacle-crossing performance optimal.On the basis of the explosive terrestrial jumping actuator and the water jet thruster,the high-pressure water jet amphibious jumping actuator and composite amphibious jumping actuator were proposed,and the system development of amphibious jumping robot design was completed.Then a series of jumping robot’s experiments were carried out,including the aerial attitude control experiment,the outdoor experiments of terrestrial advance,aquatic propulsion,aquatic jumping,terrestrial obstacle-crossing jumping and amphibious jumping experiments.The experimental results showed that the amphibious jumping robot had high-efficiency amphibious jumping ability and good aerial attitude control ability,which can provide theoretical and engineering foundation for the subsequent in-depth study of high-efficiency jumping robot.