Multi-Objective Optimization of Torsion Springs for Solar Array Deployment

For solar array deployment,most existing studies mainly focus on modeling method of deployment dynamics,characteristics of hinges,and synchronization mechanisms.However,torsion springs,which work as the drive mechanisms,have hardly attracted people's attention.In this study,the influence of the parameters of torsion springs on the deployment behavior of a solar array system with clearance joint is investigated by simulation experiments.The experimental results indicate that the deployment performances are very sensitive to the parameter values of the torsion spring.Suitable torsion springs are highly needed to improve the deployment dynamics of solar array system.Therefore,a multi-objective optimization method for the design of torsion springs is proposed.The objective of the optimization is to make the contact-impact force in revolute joint and the mass of the torsion spring minimum under the constraints of deployment time and structure strength.Finally,the effectiveness of the multi-objective optimization method is verified by an optimization example of solar array system.

Parameter optimization for torsion spring of deployable solar array system with multiple clearance joints considering rigid–flexible coupling dynamics

In this paper,four novel evaluation indices and corresponding hierarchical optimization strategies are proposed for a deployable solar array system considering panel flexibility and joint clearance.The deployable solar array model consists of a rigid main-body,two panels and four key mechanisms,containing torsion spring mechanism,closed cable loop mechanism,latch mechanism and attitude adjustment mechanism.Rigid and flexible components are established by Nodal Coordinate Formulation and Absolute Nodal Coordinate Formulation,respectively.The clearance joint model is described by nonlinear contact force model and amendatory Coulomb friction model.The latch time,stabilization time,maximum contact force and impulse sum of the contact force of the solar array system are selected as the four novel evaluation indices to represent the complex dynamic responses of a deployable solar array with clearance joints instead of the lock torque widely used in conventional works.To eliminate the gross errors caused by the nonlinear and nonsmooth mechanical properties,a hierarchical optimization strategy based on an adaptive simulated annealing algorithm and a nondominated sorting genetic algorithm is adopted for the solar array system with clearance joints.Results indicate that the effects of panel flexibility on the evaluation index responses and design optimization of the solar array system cannot be neglected.Besides,increasing the weight factor of the stabilization time index of the rigid system may compensate for the differences in optimal results of the rigid–flexible coupling system.That may provide some references for optimization design of deployable space mechanisms considering clearance joints.