A new method for erecting equipment trajectory planning

A new trajectory planning method using spline interpolation was proposed to lessen the duration and discontinuous impact in current erection equipment containing two-stage electric cylinder. By analyzing the kinematic and dynamical models for erection equipment, actuating constrains and boundary conditions are obtained. To Conduct trajectory planning, five order Bspline interpolation method was employed, and penalty function was introduced to process constrains. To conduct multi-objective optimization for B-spline trajectory, an NSGA-II algorithm was used. The intervals between adjacent control points of splines were taken as the designed variations. The calculation result was a Pareto optimal aggregate, from which the optimal solution is chosen for being the smoothest and the fastest. The simulation results show that five order B spline interpolation could achieve approximate optimal time consumption while the polynomial interpolation couldn't. And five order B spline interpolation leads to more continuous jerk than cubic B spline. That stabilizes the erection process and lessens the tracking error.