Open Loop Functions

New for 2026. Draft notes - work in progress.

Many of the sample simulations use actuator control signals which are purely a function of time (i.e., open-loop clock-based generative actuation). This approach highlights how the nature of the movement is primarily determined by the physical form and dynamics, with the motors just used to ‘activate’ the dynamics.

Following are a few samples of the simple functions used to map simulator time to a cyclic actuation.

../_images/modulo.png

Sawtooth signal created using the modulo operator applied to a monotonically increasing time signal.

../_images/square.png

Square wave signal created using modulo and the Python ternary form.

../_images/sin.png

Sine wave signal. The sin function has a period of 2*pi.

../_images/halfsin.png

Intermittent half-sine signal. The max operator suppresses the negative values.

../_images/halfsinshift.png

Shifted intermittent half-sine signal. Adding a constant to the time changes the phase.