液压控制机构，用于例如通过步进电机来控制诸如液压马达或液压缸的操作元件，其使用预设的设定点和实际值的机械反馈。 功能元件以旋转活塞的形式提供，该旋转活塞彼此相配合地相对于彼此旋转，并且用于敏感地调节从压力介质源向操作元件供应的压力介质流的方向和数量 并从其流回到罐中。 一个旋转活塞与设定点的预置点正确连接，另一个旋转活塞与用于机械实际值反馈的操作元件正确连接。 以这种方式，与通过纵向移动来驱动滑动或座阀的已知控制机构相反，设定点的旋转运动和实际值被直接相互比较。 这导致静态（定位精度，同心度）以及动态（序列真实性，路径偏差）相当大的精度。 控制机构是更好的过载安全装置，结构更简单，更经济。

For the construction of control circuits for controlling hydraulic working elements such as a hydraulic motor, hydraulic cylinder or the like, a novel hydraulic control device is described, which operates with nominal value setting, eg by stepping motor, and mechanical actual value feedback. The functional parts which serve to regulate from a pressure medium source to the working element fed and back to the tank flowing from this pressure medium flow regarding the direction and amount of sensitive, are configured as nested, mutually rotatable rotors (4, 6). Here, the rotary piston (6) is connected rotationally with the nominal value specification (2) and the other rotary piston (4) with the working element (3) for mechanical actual value feedback. In this way, the rotational movement of target and actual value can be compared directly with each other, unlike in the known control devices are operated in which a longitudinal movement slide or poppet valves. This is a considerably higher accuracy of both static (positioning accuracy, concentricity) and dynamic (episode loyalty, path deviation) accessible. In addition, the control device is overload-proof, constructed simpler and cheaper feasible.