Mechanism Design And Analysis Of A Single Actuator Continuous Hopping Robot

In the unstructured and complex terrain,the locomotivity,climbing obstacle capability and mobility of the robot is facing great challenges.Compared with wheeled robot,caterpillar track robot and legged robot,hopping robot can overcome obstacles of several times or even dozens of their own size.It can pass through various complex terrains efficiently and has obvious advantages in obstacles crossing and miniaturization.Hopping robots are favored by researchers from all over the world.Currently,most of the existing continuous hopping robots are driven by hydraulic and pneumatic,and the electric driven hopping robots are mostly intermittent hops.This paper is taken the new electric driven continuous hopping robot as the entry point and combined with the requirements of low power consumption,less actuator,compact structure,high energy utilization and rapid response,a fast-response and small-scale continuous hopping robot driven by a single low-power motor with the conversion of energy storage and release state is simple and reliable is proposed.Using the theory of mechanism,optimization design methodology,computer simulations and other theoretical tools synthetically,adopting theoretical analysis and simulation combining with prototype experimental verification,the key problems of continuous hopping robot are researched in-depth.(1)Based on the analysis and research of the existing electric driven hopping robot,taken the single-degree-of-freedom eight-bar closed-chain mechanism as the starting point of design,utilized the mechanical evolution and the characteristics of isomeric mechanisms with same kinematics,and used the method of structural exploration and institutional synthesis,a novel bilateral and symmetrical double-gear-pair ten-bar closed-chain mechanism with a single-degree-of-freedom is proposed as the hopping mechanism.And the energy mechanism is designed according to its motion characteristics.By introducing a clockwork spring with angular energy,an energy-stored actuator that meets the hopping requirements of the robot is designed.(2)The kinematics analysis of the hopping mechanism is carried out by using the Denavit-Hartenberg method,and the position vector formula of each joint point relative to the fixed coordinate system is solved.To maximize the energy stored of the robot and make the structure more compact as the optimization objective,the dimension optimization mathematical model of the hopping mechanism is established.The optimal dimension of the hopping mechanism that satisfies the optimization objectives and constraints is obtained by using the TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution)for global search algorithm.It provides theoretical data for robotic materialization.(3)The dynamic analysis and solution of the energy storage phase of the robot are carried out by using the analysis method of nonholonomic system dynamics for reference with adding the Lagrange multiplier based on the Lagrange equation of the second kind.The maximum driving torque required for the driving component of the hopping mechanism in the energy storage phase is obtained.Taking this as the design goal,the parameters of the clockwork spring in the energy-stored actuator are designed by analyzing the working characteristics of the clockwork spring.(4)The simulation model and experimental prototype of the robot are established,and the experimental platform of electric driven continuous hopping robot is designed and built.The foot trajectory tracking comparison experiment,the performance analysis experiment of the energy-stored actuator and the continuous hopping experiment were completed.And the result verifies the feasibility of the design of the hopping mechanism,energy mechanism and actuator.It proves that the hopping robot has excellent energy storage speed,stable hopping ability and good hopping performance.Its design and analysis provide an effective theoretical reference for the research of electric driven continuous hopping robots.