Electronics-free pneumatic circuits for controlling soft-legged robots

Abstract

Pneumatically actuated soft robots have recently shown promise for their ability to adapt to their environment. Previously, these robots have been controlled with electromechanical components, such as valves and pumps, that are typically bulky and expensive. Here, we present an approach for controlling the gaits of soft-legged robots using simple pneumatic circuits without any electronic components. This approach produces locomotive gaits using ring oscillators composed of soft valves that generate oscillating signals analogous to biological central pattern generator neural circuits, which are acted upon by pneumatic logic components in response to sensor inputs. Our robot requires only a constant source of pressurized air to power both control and actuation systems. We demonstrate this approach by designing pneumatic control circuits to generate walking gaits for a soft-legged quadruped with three degrees of freedom per leg and to switch between gaits to control the direction of locomotion. In experiments, we controlled a basic walking gait using only three pneumatic memory elements (valves). With two oscillator circuits (seven valves), we were able to improve locomotion speed by 270%. Furthermore, with a pneumatic memory element we designed to mimic a double-pole double-throw switch, we demonstrated a control circuit that allowed the robot to select between gaits for omnidirectional locomotion and to respond to sensor input. This work represents a step toward fully autonomous, electronics-free walking robots for applications including low-cost robotics for entertainment and systems for operation in environments where electronics may not be suitable.

Massive Pressure Amplification by Stimulated Contraction of Mesoporous Frameworks**

“…Carbon dioxide is a non‐flammable, non‐toxic, and inexpensive gas, the molecule of which shows a quadrupolar moment and high adsorption enthalpy [18] . It is an ideal fluid for the operation of pneumatic devices and machines such as dampers, fire extinguishers, or life jackets, [19] and more recently is gaining attention in the field of pneumatic logic circuits for electronics‐free control of soft‐legged pneumatic robots [20] . This motivated us to assess the value of carbon dioxide for high‐pressure amplification by NGA materials.…”

A mechanical metamaterial with reprogrammable logical functions

“…Although the subsequent electronic transistor 2 and magnetic storage 3 -based computation approach is advantageous in terms of calculation speed and data density, the robustness of mechanical logic is beneficial for applications under extreme conditions 4 , 5 , such as high temperature and radiation exposure, while maintaining their designed logical functions. Moreover, potential applications of mechanical computation for constructing intelligent mechanical systems have renewed the interest in mechanical computation in the last decade 6 – 8 . The intelligence of mechanical systems including soft robotics 9 , 10 , microelectromechanical systems (MEMS) 11 , 12 , and robotic materials 13 , 14 , depends upon their embedded logical functions.…”

Modelling and implementation of soft bio-mimetic turtle using echo state network and soft pneumatic actuators

“…However, the work is depend on morphing the robot actuator and analysis its motion and it does not mention the analysis study of the robot motion with the proposed actuator. Electronics free turtle which use oscillating valves to allow pressurized air in and out in a predetermined order is proposed 27 . The robot is tested by experiments depends on the motion gait analysis for the robot not the dynamics model analysis.…”