On this page... (hide)
Animals can vary joint impedance via co-contraction of antagonistic muscles acting at a joint, tuning the joint for a particular task. Cyclic motions, such as running and hopping, and other tasks,
On this page... (hide)
Animals can vary joint impedance via co-contraction of antagonistic muscles acting at a joint, tuning the joint for a particular task. Cyclic motions, such as running and hopping, and other tasks, such as moving an arm, catching a ball, or landing from a jump, see advantages such as lowered metabolic costs, lowered impact forces, and improved dynamic stability. While researchers have created a range of robotic systems with tuned impedance, such as the Sprawl, Stickybot, and Perching robots, they cannot change their impedance after manufacture. Tunable stiffness devices have been designed, but are often heavy, bulky, mechanically complex, and inefficient, making them unsuitable for small, mobile platforms. We are designing structures based on electroactive polymers that are lightweight and simple and can change their stiffness and damping properties very quickly.
Changing the electrical boundary conditions around an EAP can influence the coupling between mechanical and electrical work. A sample circuit, such as the one shown below, can use high-voltage optocouplers to switch the electrical boundary condition on the actuator. This changes the rate at which charge moves on and off the actuator, which changes the effective damping.
The geometry of the actuator frame can be designed to convert the film's rel