An actuator control system includes a motorized joint having first and second members rotatable relative to one another. An actuator is coupled with the motorized joint and is configured to rotate the first member relative to the second member in response to an input including a voltage, a current, or any combination thereof. A controller is coupled with the actuator and is configured to control the input using a control algorithm. The control algorithm controls the input based upon a mathematical model of biological muscle actuation that models titin as a filament which winds around actin during muscle actuation. In implementations the mathematical model includes mathematical representations of a contractile element, a viscous damping element in parallel with the contractile element, and a spring in series with the contractile element through a pulley and simultaneously in parallel with the contractile element.