A tunable actuator joint module of a robotic assembly comprises an output member and an input member, where the output member is rotatable about an axis of rotation. A primary actuator (e.g., a motor) is operable to apply a torque to rotate the output member about the axis of rotation. A quasi-passive elastic actuator (e.g., rotary or linear pneumatic actuator) comprising an elastic component is tunable to a joint stiffness value and is operable to selectively release stored energy to apply an augmented torque to assist rotation of the output member and to minimize power consumption of the primary actuator. The tunable actuator joint module comprises a control system having a valve assembly controllably operable to switch the quasi-passive elastic actuator between an elastic state and an inelastic state during respective portions of movement of the robotic assembly (e.g., a hip or knee joint of an exoskeleton). Associated systems and methods are provided.