Artificial motor-muscles (suggestion: Mokels) are actuators out of an active diamondoid metamaterial that can perform pull but also push action with high energy densities beyond the ones seen in biological muscles tissue and even beyond combustion engines like it's typical [add ref] for all AP technologies of technology level III. On the small scale they resemble some form of motors but on the large scale they seem sort of like a crystalline muscle thus the term motor-muscle.
The material consists out of many minimal sized active units. Each of them contains one or more electromechanical or chemomechanical motors that extend or shrink the units length. For fault tolerance a the units must be connected parallel and serial in a hierarchical fractal fashion [TODO add info-graphic].
When a mokel metamaterial is actuated a volume changing extension or shrinkage takes place. This is in contrast to interfacial drives (which are essentially infinitesimal bearings with motor/generator cells included) where only a shear deformation is present which does not change the actuators volume.
With motor-muscles built out of modular microcomponents beside electromechanical converters or chemomechanical converters other microcomponents like energy storage cells could directly be incorporated (possibly in a choosable ratio) instead of feeding the energy in from an external source. This way one can trade efficiency (through lowering of power transport distance) for maximal force and power density.
All the power-supply infrastructure for the motors must be incorporated making the design quite complex. Combining mokel with metamaterial elasticity in the directions normal to the pulling action (transversal directions) and making the mokel long and thin one gains some kind of active rope.
Mokel would undoubtedly provide a boost for robotic engineering.
Due to their high power density mokel can be distributed sparsely into active materials. Chemical energy storage in contrast has high volume but can be located far off sight since with AP technology energy transmission is easy.