## 1 Introduction
An interesting area of future applications is tensegrity-based metamaterials with unusual mechanical properties [21; 26; 27]. Examples of the analyses presented in this paper prove that tensegrity modules and lattices have all four key elements of inherent smartness, that is: self-control, self-diagnosis, self-repair and self-adjustment (active control). Self-control of tensegrity systems consists of self-stiffening of the structures under the applied load that causes displacements consistent with the infinitesimal mechanism mode. External loading acts similarly to the self-stress: it eliminates the singularity of the problem, additionally prestresses the structure and stiffens it. Self-diagnosis refers to the possibility of damage detection and identification by measuring internal forces in active members. Damage of one structural element affects the distribution and level of self-stress in the whole structure. Self-repair of tensegrity structures is realized by adjusting self-stress forces. A proper change of pre-stressing level can compensate the damaged element and restore the values of structural displacements from before damage. Self-adjustment (active control) in regard to tensegrity systems is related to the ability of self-adjustment through self-stress forces. Both the pre-stressing of the whole structure and its part causes stiffening of the system and reduction of its displacements. Therefore, active control of tensegrities can be realized by adjusting the level of self-stress in only one selected part of the structure. The above properties are especially found in tensegrity structures because of the infinitesimal mechanisms stabilized by the self-equilibrated forces. The presence of infinitesimal mechanisms makes tensegrities more sensitive for the control of their mechanical properties. This is the unique feature of tensegrities that distinguishes them from other structures under pre-stress. The present paper discusses variable aspects of the structural control of smart systems with the focus on tensegrity structures. Analyses performed for this study prove that tensegrities have all of the above-mentioned properties, which they owe to infinitesimal mechanisms balanced with self-stress states. The presented examples of the analyses of different tensegrity modules and multi-module structures show that it is possible to control their properties by adjusting the pre-stressing forces. After the above introduction, the second section of this paper is dedicated to the description of self-control of structures, from a simple two pin-joined cables, through a three-strut simplex single module to a plate-like multi-module tensegrity lattice. The influence of self-equilibrated forces, as well as additional self-stress due to geometrically non-linear properties on the response of the structures is analyzed. The possibility of self-diagnosis by monitoring of normal forces is presented in Section 3. The analysis of the self-repair of plate-like tensegrity is described in detail in Section 4. The aim of Section 4 is to show how the self-stress of one module in the plate-like tensegrity can help in the active control of the response of the structure. The paper is summarized in Section 5 with some potential technical/engineering applications proposed.