To increase the compression between the dominoes discussed above and here: Tensioned soft shaft, but now made semi-rigid with dominoes for example, you could use motors with gearboxes at various points, or in limited cases you could maybe only use gearboxes, if I understand the physics of that correctly.
You’d have your slack structure sitting atop the ground station. If it keeps sitting atop the ground station even in operation, you can just use motors in the ground station to tension the lines in the structure. The ends of the arms of the ground station act as the stoppers. If not, and the structure is meant to go airborne, you’d need a stopper on each line to prevent the structure from going slack again from the unreeling of the lines.
That stopper could be [1] a clamp in the bottom dominoes, clamping the domino to the line, [2] a motor with a drum in selected dominoes, keeping the tension in the lines that the motor acts on, or, I think, [3] a gearbox in the bottom dominoes, multiplying the tension in the line coming from the ground station to the gearbox by the gear reduction of the gearbox, and dividing it by the number of lines coming from the gearbox going into the structure.