Fig. 7. The integration of a bistable valve with the autonomous robot.
(A) The working mechanism of the mechanical bistable valve. When the membrane bends upward, it blocks the pneumatic tube inside the top chamber. As a result, the pressurized air flows into the actuator, inflating the pneumatic actuator. Once the pressure of the top chamber reaches a critical pressure Pc, the membrane snaps, the air tube in the top chamber is no longer blocked, and the pressurized air can flow out to the atmosphere, deflating the pneumatic actuator. (B) The bistable valve translates a constant pressure input to a periodically varying pressure output (supplied to the pneumatic actuator). (C) Demonstration of autonomous motion in response to various light and heat sources. Scale bar (C), 5 cm.