Motivation. Robots are usually divided into land, underwater and aerial vehicles all of them having their specific research and engineering challenges. In few cases all-terrain robots can adjust to different environments or amphibian robots are built to move from water to land. The challenge almost unexplored so far is locomotion in the mixture of those environments. Problem definition. This PhD topic explores new locomotion mechanisms for exploring flooded abandoned mines. It involves the design, prototyping and verification of robots, with focus on actuation, for locomotion in fluids with different properties. The robots will move on solid ground, in water, as well as in the environments between them; in mud of different consistencies, clay, oil, wet snow, loose gravel, etc. Expected results. The expected results of this topic are physical robot prototypes which are demonstrated in real environments together with modelling and control of locomotion. Requirements. The successful applicant should have a M.Sc. or equivalent in Mechanical Engineering, Mechatronics or other related areas with hands on experience. Apart from a strong theoretical background and practical skills in robotics and physics, this assignment requires independent thinking and creative problem solving. The work will be conducted in European Union project ROBOMINERS in an multinational team. We therefore are looking for people who are good at working with others. You will need to be prepared for field tests in unique and challenging environments, such as stone caves, ice caves and quarries underwater, including possibly unpleasant weather conditions.