Resonance-driven dynamic manipulation: Dribbling and juggling with elastic beam

This paper presents a new device and a method for dynamic manipulation. The device consists of a planar robotic arm and an elastic beam as an end-effector. Using it the elastic end-effector will tend to increase performance and energy efficiency while executing dynamic and repetitive tasks. Through the control of the beam vibration and resonant modes, we modify the state of manipulated objects. For lightweight objects the control is provided through the intermittent contacts without changing dynamics of the beam. However, we show that by using proper synchronization technique continuous-phase contacts are also possible. Juggling and dribbling of a ball are considered to be an alternating non-prehensile catching and throwing task. Such alternating decelerating and accelerating impacts on the ball and the curvature of the beam at the time of impact will stabilize the cyclic orbit of the ball. By proper analysis of continuous-time contact and dynamics of the beam we establish a rhythmic movement of the system. With the variation of frequency and amplitude of the beam it is possible to switch between different dynamic actions such as juggling, dribbling, throwing, catching and balancing.