| With the accelerating automation process of modern industry and rapid development of social economy,the service level requirements of robots have been increasing.People urgently hope that robots can better serve and assist humans to complete complex tasks.As a human-like upper limb system with two arms,the humanoid dual-arm robot is a combination of bionic,intelligent and other engineering technologies,and has received more and more attention from researchers because of its high flexibility and reliability.At present,one of the core problems of humanoid dual-arm robotics is its trajectory planning,including dual-arm coordination planning,dual-arm collision avoidance,and other problems.In this paper,the trajectory planning of redundant humanoid arms is studied by analyzing the theoretical basis,building the simulation environment,and performing simulation verification for the coordinated operation of humanoid dual-arm.Firstly,the positive kinematics of the humanoid dual-arm is analyzed,and the geometric method is adopted to solve the inverse kinematics of the dual-arm because the numerical iterative method will cause the problem that the inverse kinematics solution has iterative error;meanwhile,the working space of the dual-arm is analyzed by the Monte Carlo method;additionally,the numerical verification of the right arm inverse solution expressions is conducted to illustrate the accuracy of the inverse solution expressions,which provides the basis for the research of the trajectory planning method of the dual-arm.Secondly,taking the right arm of the redundant humanoid dual-arm as an example,a trajectory planning method based on singularity optimization under multiple constraints is proposed.This method determines the point-to-point trajectory planning strategy by describing the mathematical model of the redundant humanoid arm.Considering the obstacle constraints and kinematic physical constraints in the operation of the humanoid arm,the method converts the trajectory planning problem into the trajectory parameterization optimization problem.Then,an "operability" is defined to constitute the fitness function and optimization goal and the trajectory selection scheme of the humanoid arm based on the particle swarm optimization algorithm is established.The method is applied to the trajectory planning of the humanoid right arm through simulation experiments to achieve static obstacle avoidance,kinematic physical constraint avoidance,and singularity avoidance requirements.Thirdly,based on the trajectory planning method of the humanoid right arm,the coordinated planning method of the humanoid dual-arm is studied.Taking the point-to-point planning tasks as the research objects,a coordinated planning method for the humanoid dualarm based on the master-slaver strategy is proposed.In this method,the master arm and slave arm operation trajectories are planned separately by cubic polynomials in the joint space.Based on the parameterization description,the trajectory planning problem of the master arm and the slaver arm is transformed into the trajectory parameterization optimization problem,and the motion trajectory optimization schemes based on the particle swarm algorithm for the master arm and the slaver arm are established respectively.Finally,a three-dimensional model of the humanoid double-arm is drawn,and the simulation environment and simulation platform of the humanoid dual-arm are built.Based on the master arm simulation platform,another trajectory planning method,Gradient Projection Method(GPM),is used to compare with the proposed method.The experimental results and data illustrate that the proposed method has less searching variables and smaller position deviation,which can also achieve the effect of collision avoidance.In addition,the simulation experiments of the coordinated trajectory planning based on master-slaver strategy for dual-arm are conducted,and the experimental results show that the method not only avoids the interference between dual-arm and obstacles as well as between two arms,but also ensures that the physical constraints of kinematics are not exceeded during the operation of dual-arm and their configurations do not produce singularities,which verifies the effectiveness of the method. |
