Apparatus for controlling active mounts

Claim 1

An active mount exhibiting an uncontrolled, frequency-dependent dynamic stiffness K M (Ω) for reducing mechanical vibration transmitted within a mechanical system which includes said mount, a vibrating device exhibiting a frequency-dependent dynamic stiffness K E (Ω) and a support exhibiting a frequency-dependent dynamic stiffness K S (Ω), comprising: (a) a spring means interconnecting said vibrating device and said support for providing passive support of a static load from said vibrating device; (b) an actuator for providing phased dynamic loads to counteract said mechanical vibration from said vibrating device and reduce vibration transmitted to said support, said actuator connected in parallel spring relation to said spring means; (c) a sensor collocated with said active mount for supplying an input signal to a closed-loop feedback control system; (d) said closed-loop feedback control system providing an output control signal to said actuator responsive to said collocated sensor and further including an amplifier which amplifies said input signal, and means for reversing the sign of said input signal; and, (e) said mechanical system having a natural frequency fn, said mechanical system being characterized by a ratio of a series dynamic stiffness K SD (Ω) to an elemental dynamic stiffness, K X (Ω), being related by an expression K SD (Ω)/K X (Ω)≧2   for Ω≧ 2f n where K X (Ω) is selected from the group consisting of K M (Ω) and K S (Ω) and K SD (Ω) = K Y (Ω)K Z (Ω)/[K Y (Ω)+K Z (Ω)] with K Y (Ω) and K Z (Ω) being a remaining two dynamic stiffnesses from a group consisting of K E (Ω), K M (Ω) and K S (Ω) after K X (Ω) has been designated.