In recent years, vehicles equipped with EPS (Electric Power Steering) have come into widespread use. This is because EPS is better than HPS (hydraulic power-steering) in improving fuel consumption and reducing emissions. However, most present power-steering systems, including HPS, have mere function of assist based on driver's torque. There exist only few vehicles equipped with EPS that has a function of improving vehicle stability. Because, it requires vehicle state signals such as yaw rate etc. Taking this situation into consideration, we developed the TCAS with the keywords of 'environment' and 'stability' that acts without vehicle state signal sensors, that is, the same system as the present EPS. In an EPS system, a motor is applied via a reduction gear to steering mechanism. This system has both frictional loss torques and spring characteristics or backlash in the steering mechanism. When a driver steers, Alignment torque is generated via the tires and the road surface. This paper proposes an advanced control strategy to improve steering maneuverability in the emergency steering or on slippery roads, with TCAS (The Torque Controlled Active Steer), which means EPS with advanced control method. TCAS, which is based on the alignment torque estimation and the feedback compensation aims to improve returnability by using the alignment torque estimation on the various situations. By vehicle experiment, we confirmed that our controller with the alignment torque compensation improved vehicle dynamics stability, because of the improved returnability.
Development of Torque Controlled Active Steering Using the Estimated Alignment Torque for EPS
Entwicklung einer vom Drehmoment gesteuerten Aktivlenkung mit dem geschätzten Ausrichtmoment der elektrischen Servolenkung EPS
Review of Automotive Engineering (JSAE) ; 26 , 1 ; 85-90
2005
6 Seiten, 13 Bilder, 1 Tabelle, 6 Quellen
Aufsatz (Zeitschrift)
Englisch
Fahrzeuglenkung , Servolenkung , elektrische Betätigung , hydraulische Betätigung , Hydrosteuerung und -regelung , elektrische Steuerung und Regelung , Reifen (Fahrzeugreifen) , Straßenbelag , Manövrierfähigkeit , Umweltumgebung , Stabilität , Reibungsverlust , Drehmomentregelung , dynamische Stabilität , Rückstellkraft
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