A novel design of Movable Gripper for non-enclosable truss climbing

In this paper, we present a novel Movable Gripper (MovGrip) which targets on climbing non-enclosable rectangular trusses such as bridges and space stations. It is designed with a transformation mechanism which provides the features of parallel grippers, rotatory grippers, and active wheels. For truss climbing, MovGrip acts as a parallel gripper which allows the change in gripping width according to different size of trusses. Since MovGrip is equipped with active wheels, fast climbing motion can therefore be realized. Moreover, MovGrip can be transformed into a mobile platform which is suitable for the navigation on ground. It weighs only 500 grams with a climbing speed of 3 cm/s. To maintain the climbing stability, we steer the rotation axis of wheels. By this, a directional pulling force (from MovGrip to truss surface) can be distributed from the drive force of wheels which pulls MovGrip towards the truss while climbing. Experimental results show that tilting of MovGrip can be auto-adjusted based on the proposed design. Also, it is shown that the load carrying capability of MovGrip is approximately 1 kg which is 2 times of its weight.