An orthotic device is provided which includes a first structural element; a second structural element which is rotatably attached to the first structural element across a joint; a first rotary actuator which imparts rotational motion to the first structural element relative to the second structural element about a first axis; and a second rotary actuator which imparts rotational motion to the first structural element relative to the second structural element about a second axis. Each of the first and second rotary actuators is selected from the group consisting of parallel eccentric actuators and rotary actuators.