Abstract
The present paper discusses the possible existence of elastic dynamic instabilities appearing during non-linear dynamic response of tensegrity systems such as tripod simplex and Geiger dome. A geometric non-linear dynamic procedure had been implemented to solve the equations of motion using a step by step numerical integration method and a modified Newton-Raphson scheme. A criterion in the form of a degree of stability derived as a function of the time evolution of the variation in strain energy and complementary strain energy is used for the investigation. The effect of active control on the stability of the structure is also studied. Active damping is successfully added to the structure using collocated displacement actuator-force sensor pairs located on the lower end of each cable and a robust control strategy based on decentralised collocated integral force feedback. It has been shown that the instability problem of tensegrity systems may be solved using active control.