A small-scale actuator with passive-compliance for a fine-manipulation deep-sea manipulator

Underwater handling of objects as much as any manipulation tasks on land are dependent on sensory feedback to close the control loop between performed action and achieved result. In state-of-the-art underwater manipulation systems this feedback is mainly provided by vision that reaches its limits in hazy water conditions, often caused by the manipulation procedure itself. Tactile sensors that provide the additional modality of haptic feedback, are therefore an interesting topic for underwater robotic research. The main goal of the SeeGrip project at the DFKI Robotics Innovation Center in Bremen, Germany, is to develop a multi-limb manipulation system with tactile force-feedback that enables operators to work under these ambient conditions. In this paper, we describe the hydraulic actuation-system of this manipulator.