The biggest feature of the differential planetary roller screw is that it has a differential motion,which can obtain a smaller lead than the general planetary roller screw.When applied to the electromechanical actuator,a larger deceleration ratio can be obtained under the condition that other conditions remain unchanged,and because of its compact structure,the electromechanical actuator can have a higher power volume ratio and power mass ratio. More suitable for high speed and heavy duty workplaces.