Research on Load Damage Reproduction Error of CDC Shock Absorber Equipped Vehicle in Spindle Coupled Road Simulation Test with Real Vehicle Dynamic Current Playback

Abstract

Spindle coupled road simulation is an essential bench technique for chassis durability verification. For vehicles equipped with CDC shock absorber, most existing bench tests adopt constant amplitude fixed current excitation, which cannot reproduce the time varying solenoid valve current measured on real roads, resulting in non-negligible load and fatigue-damage reproduction deviation. To quantify such errors, this paper implements real vehicle dynamic CDC shock absorber current synchronous playback based on self-developed current playback hardware on an MTS 329 LT spindle coupled test bench. Two test schemes, constant current iteration and real vehicle dynamic current playback iteration, are compared. Time domain load response, inverse transfer function frequency domain characteristics, rain-flow counting fatigue damage of shock absorber towers and suspension control arms are analyzed. Test results demonstrate that constant current schemes produce obvious damage bias: the damage relative error can reach 27.4% for strut tower vertical acceleration and 31.8% for lower control arm strain damage. The system transfer function presents frequency segmented features under dynamic current conditions: significant time varying disturbance occurs within 0-10 Hz, while characteristics above 10 Hz remain basically stable. This work reveals the error mechanism between the two test schemes and provides test scheme reference for durability bench verification of electronically controlled suspension vehicles.