Abstract: A system for active compensation of undesired relative movement particularly during loading of cargo comprising a long-periodic acting system for compensation of static loading caused by the load and a short-periodic acting system for active compensation of undesired relative movement of the load relative to a reference value. The long-periodic system includes a compensating cylinder provided with two pistons acting in opposite directions, the cylinder being connected to one or more pressure loaded reservoirs operating pneumatically. The short-periodic system includes at least one hydraulic cylinder and the position of the short-periodic system is determined by measurement of acceleration of the end of the loading crane beam by accelerometers.