Tuned vibration absorber for active vehicle suspension

An apparatus for use in an active suspension system, said apparatus comprising a mass damper for damping a first vertical resonance of a wheel having a vertical diameter and a horizontal diameter, said wheel defining a wheel plane that passes through a center of said wheel and the vertical and horizontal diameters of the wheel, and a transverse wheel plane that is perpendicular to said wheel plane and that intersects said wheel-plane along said vertical diameter, said mass damper including a damping mass coupled to said wheel, said damping mass being constrained from motion relative to said wheel in all but a vertical direction, said damping mass having a mass distribution that is asymmetric relative to said transverse wheel plane, and a spring-damper-bearing system coupled to said damping mass for guiding vertical motion of said damping mass relative to said wheel, wherein said spring-damper-bearing system comprises a first spring-damper-bearing assembly disposed on a first side of said transverse wheel plane and a second spring-damper-bearing-assembly disposed on a second side of said transverse wheel plane.