Design of a type of deployable/retractable mechanism using friction self-locking joint units

Abstract To develop a new type of deployable/retractable mechanism, the joint friction effect is considered in this paper. Several types of mechanisms with self-lock and unlock functions are presented as design units. These units can be constructed in parallel, in series, or in both ways to form a type of large deployable mechanisms. The self-locking and unlocking conditions of the designed units are analysed, and a new type of deployable mechanism, which can be extended and retracted along a straight line, is designed with the proposed unit constructing method. The relationship between the unit constraint matrices at various configurations is presented. During the moving process, the topology structure of the deployable mechanism is variable, including changes of the joint direction and the joint number. A cable driving prototype with only one motor is built, and relevant simulations are conducted to verify the design method. The results demonstrate that the joint units perform perfectly and that a larger dimension deployable mechanism can be established.