Theoretical Research On Leg Mechanism Design Of Closed Chain Eight-bar Multi-legged Robot

At present,the ground mobile robot is continuously applied in industry,medical treatment,service,education,military and other important fields.Due to the different mobile devices,all kinds of mobile robots have their own advantages and disadvantages.The foot robot has strong terrain adaptability,and the leg mechanism is the key part of the foot robot.Its structure is mainly open chain and closed chain.Compared with the open chain mechanism,the closed chain mechanism has the advantages of less degrees of freedom and low control difficulty.It has great potential in the leg mechanism design of foot robot.In the design of closed chain mechanism,the mode of traditional design theory is usually "Structure?Trajectory",and then optimize the trajectory.Therefore,from the point of view of designing the closed chain mechanism base on the end trajectory,this paper puts forward a design theory of the closed chain linkage mechanism based on the end track,and carries out three aspects of the research on the construction of the kinematic model of the closed chain eight link mechanism,the extraction of the end track curve parameters,and the design of the regeneration homotopy solution program.Taking a closed chain eight bar mechanism as a model,combined with a typical end track curve,a model calculation program is designed,and a closed chain eight bar mechanism which can complete the end track is designed.Taking the closed chain eight link mechanism as the leg mechanism,the model design of the single leg and the whole machine of the multi legged robot is carried out,and the simulation test of the whole machine is carried out.At the same time,the single leg prototype and the small machine are developed,and the experimental verification of the actual terrain environment is carried out.The specific research content includes the following aspects:(1)The kinematic model of closed chain eight link mechanism is established.Using the number synthesis of advanced kinematics,the evolution direction of two kinds of closed chain kinematic chains is defined,and the evolution direction of eight bar closed chain mechanism corresponding to two kinds of closed chain kinematic chains is defined.The construction principle of kinematic equation of eight bar closed chain mechanism is proposed,and the kinematic model of eight bar closed chain mechanism in accordance with the evolution process is established,and the iterative elimination method is used to simplify all the kinematic model.(2)A method of feature extraction of end track curve is proposed.Abstract research on the typical robot leg mechanism is carried out,the end trajectory curve generated by the mechanism is obtained and classified,the characteristics of each trajectory curve are analyzed,three types of task points for all closed chain eight bar mechanisms are determined,and the change rule of parameters in each task point type is described.Taking the end track formed by a typical leg mechanism as the research object,the real value extraction steps of the track parameters are determined.(3)The eight-bar kinematic model is verified by an example.By using the basic theorem and lemma in the theory of regenerative homotopy,the general flow of solving the kinematic model of the closed chain eight bar mechanism is given,the calculation program of the kinematic model is designed,the function of each sentence segment in the program is described,and the stephenson-iii evolutionary mechanism is taken as an example to verify,all homotopy tracking results are listed,and the scale size of the closed chain eight bar mechanism is determined.(4)The simulation analysis and prototype development of the multi legged robot are carried out.Based on the scale size of the closed chain eight bar mechanism,the structural size scheme of the leg mechanism of the multi legged robot is determined,the single leg mechanism and the whole machine model of the multi legged robot are constructed,and the motion simulation of the whole machine on three terrain is carried out respectively,and the performance of the multi legged robot is judged from three angles.At the same time,the single leg experimental prototype and the small prototype of the eight-legged robot are developed,and the actual terrain environment experiment is completed.