Research On Trajectory Optimization Algorithm Of Small Industrial Robot Based On Dynamics

As the level of automation and intelligence of industrial production lines continues to increase,the trajectory planning capabilities of industrial robots are facing more stringent requirements.The time-optimal trajectory planning of industrial robots is an important technology to improve production efficiency,and has attracted the research interest of many researchers at home and abroad in the past few decades.How to make the end effector of an industrial robot move along a predetermined Cartesian space path in the shortest time while satisfying kinematic constraints and dynamic constraints is still a difficult and important problem.Therefore,this paper takes the trajectory optimization algorithm of small six-axis robot as the research object,and plans the optimal trajectory to meet the requirements of industrial application for different constraints and objective functions.The specific research contents are as follows:First,the kinematics modeling is performed according to the improved DH parameters of the small six-axis robot,the forward kinematics is analyzed and the homogeneous transformation matrix between the links is calculated.In order to avoid excessive matrix inversion operation by algebraic solution,the combination of geometric projection method and Euler angle solution is chosen to solve the inverse kinematics of small six-axis robot.The dynamics of small six-axis robots were modeled by Newton's Euler iteration method and Lagrange equation method.The dynamics algorithm was verified by writing MATLAB program,and the computational efficiency and calculation error of the two dynamic algorithms were compared.Secondly,the time-optimal trajectory planning algorithm for small six-axis robots along a predetermined path is introduced.Based on the complete nonlinear dynamics of the robot,the algorithm uses the path parameterization method to establish a mathematical model of time optimal trajectory planning.The convex relaxation method is used to transform the non-convex constraints introduced by the viscous friction into convex constraints,and the nonlinear objective functions and constraints are transformed into second-order cone constraints.Develop an appropriate discretization scheme to transform the trajectory optimization problem into a finite-dimensional second-order cone programming problem.Write the MATLAB program of the time optimal trajectory planning algorithm,and call the convex optimization solver SDPT3 to obtain the numerical solution of the time optimal trajectory.Thirdly,for the shortcomings of the time-optimal trajectory planning algorithm,the time-optimal trajectory planning algorithm is improved through principle analysis,model derivation,program realization: more kinematic constraints are applied to meet the actual demand;the energy consumption and the total jerk limit,thereby reducing the energy consumption of the optimal trajectory of the running time,limiting the sudden change of the joint acceleration,improving the tracking performance of the trajectory;introducing the speed-dependent torque constraint to further reduce the running time of the time optimal trajectory.Finally,in order to verify the feasibility of the time-optimal trajectory,a Simulink-ADAMS electromechanical joint simulation platform for small six-axis robots was built,and the optimal trajectory generated by the trajectory optimization algorithm was simulated and tested.The trajectory runs on a small six-axis robot experimental platform to verify the effectiveness of the algorithm and the feasibility of the optimal trajectory.