Form-finding of tensegrity structures based on IAFSA

To solve the form-finding problem of large-scale and nonregular tensegrity structures, an improved artificial fish swarm algorithm (IAFSA) is proposed on the basis of the force density formation of a tensegrity structure. First, the equilibrium equations for a tensegrity structure are developed based on the force density method. Then, a set of appropriate values of force density is found by the IAFSA in the force density space to make the rank of the equilibrium matrix satisfy the required conditions. As a consequence, the equilibrium configurations of the tensegrity structure can be derived. Furthermore, by employing the position information of the current global best artificial fish and the behaviors of swallowing and leaping of the artificial fish, the IAFSA has a higher search efficiency. Moreover, the use of leaping behaviors of the artificial fish makes the IAFSA have the ability to find global extremums. With the expandable octahedron as an example, its form-finding problem is conducted by using the IAFSA. Experimental results indicate that the form-finding results of the IAFSA are reliable. Compared with the conventional artificial fish swarm algorithm, the IAFSA has a higher convergence precision and a better average optimum value.