Multi-chamber elastic pneumatic actuators are known. Festo has a long history in this area. Here's their mobile robot with a pneumatic hand.[1] They have ornithopters, fish, and other biologically-inspired forms. These are demos. Their business is selling pneumatic actuators.
They've advanced this technology considerably. It's been known for a long time that a good way to do actuators with variable compliance was with pneumatic actuators driven from both sides through proportional valves near the actuator. Festo has been able to do this with excellent non-clunky mechanical engineering.
To do this sort of thing, you need a serious mechanical design and build facility staffed by people who know how to build stuff. Universities cannot do this with grad students.