A principle for designing self-adjusting mechanisms by insert additional degrees of freedom into the machine is described. In these mechanisms, interaction of the working tool with the material being worked upon automatically sets its unique velocity, and if the external resistance is velocity-dependent the machine attains a stable operation. One of these principles is a type of servomechanisms, the advantage of it is a direct mechanical control without conversion of input into any control signals. These devices are less complex than traditional controllers, and are much easier to design. Another one is a self-adjusting elevator with one and half degrees of freedom. It contains two linked parts, each capable of working only in strictly unidirectional mode - a cable and a rod connected to a piston-cylinder assembly; their alternate action switches spatial structure of the mechanism at a required time. The third one is a portable device for lowering loads, proposed, in particular, as self-rescue gear. Finally, the book describes a "mechanical rectifier" that allows effectively utilize energy of any chaotic motion, such as surf waves, detrimental machine vibrations, etc.