Reducing Power Consumption of an Active Suspension System Using Improved Control and/or Energy Harvesting Module

Authors

Dr. Thinh Pham, Dr. Steven Wilkins,
TNO Powertrains, Helmond;
Dr. Christophe Lauwerys, Miguel Dhaens,
Tenneco Automotive Europe, Sint-Truiden

Summary

This paper investigates various methods to reduce the power consumption of a hydraulic active suspension system (AS) using improved control strategy or additional hardware with energy harvesting capability.

Besides skyhook and other rule-based control strategies, control of the AS is typically formulated as an optimal control problem with an objective compromising different required performances namely, ride comfort, road holding (e.g. measured by vehicle body acceleration, displacement between wheel and road surface respectively), suspension deflection and control force. However, it is noted that reducing the control force does not always reduce the power consumption of the AS. That is because the AS power consumption depends not only on the damping/acting force but also the actuator velocity. This paper extends the conventional objective to include the AS power consumption in the model predictive control framework. Simulation results show up to 20% power consumption reduction compared to a baseline control
strategy (without inclusion of the AS power consumption in the objective function) while maintaining the same ride comfort level for the vehicle travelling over a speed bump.

Additional to the improved control strategy, this paper also investigates the power consumption reduction of the AS equipped with an energy harvesting module, being capable of recuperating the suspension power which is usually wasted. The energy
harvesting module makes use of the SKF/TUe tubular permanent-magnet actuator (TPMA) with supercapacitor to store the harvested energy. The TPMA is modeled as a linear motor with quasi-static power-based approach for the sake of power consumption analysis. The developed TPMA model is included in an integrated vehicle model with the AS to perform the model in the loop assessments for power consumption reduction of the AS with energy harvesting module.

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