The University of Texas Center for Electromechanics (UT-CEM) has been developing active suspension technology for off-road and on-road vehicles since 1993. The UT-CEM approach employs fully controlled electromechanical (EM) actuators to control vehicle dynamics and passive springs to efficiently support vehicle static weight. The program has completed three phases (full scale proof-of-principle demonstration on a quarter-car test rig; algorithm development on a four-corner test rig; and advanced EM linear actuator development) and is engaged in a full vehicle demonstration phase. Two full vehicle demonstrations are in progress: an off-road demonstration on a high mobility multiwheeled vehicle (HMMWV) and an on-road demonstration on a transit bus. HMMWV test results are indicating significant reductions in vehicle sprung mass accelerations with simultaneous increases in cross-country speed when compared to conventional passive suspension systems.
Additionally, original projections of low power requirements for suspension actuators are being confirmed. The 3,400 kg (3.75 ton) vehicle being tested utilizes a 5 kW alternator to provide suspension power. Power conditioning circuits limit the continuous deliverable power to 4 kW, which corresponds to 1.2 kW/metric ton (1.4 hp/ton).