The steer-by-wire system severs the mechanical link between the steering wheel and the steering gear. This configuration enhances the angular transmission characteristics. Entering the nonlinear region of the tires could result in a reduction in the vehicle’s steering gain. In order to improve the comfort of vehicle steering operation, we have developed a variable transmission ratio controller for the steer-by-wire (SBW) system. This controller utilizes information on the vehicle speed and steering wheel angle to generate a variable transmission ratio coefficient, thereby adjusting the steering ratio. We introduce a multi-objective comprehensive evaluation index that takes into account vehicle lateral deviation, driver steering burden, vehicle stability, and safety. To harmonize the transmission ratio weights of constant steering gain, we employ the coefficient of variation method. Ultimately, a fuzzy neural network is employed to craft a nonlinear controller. We conducted steady-state circular motion tests, double lane-change tests, and step input tests to validate the performance of the variable transmission ratio control. The results suggest that, in comparison to conventional fixed transmission ratio systems, the variable transmission ratio control within the steer-by-wire system significantly alleviates the driver’s operational burden while enhancing the vehicle’s handling stability and safety.

To realize the commercial application of metal bipolar plates in proton exchange membrane fuel cells (PEMFCs), it is important to develop coatings that are both durable and have low interfacial contact resistance (ICR). In this study, atmospheric plasma spraying (APS) was utilized to prepare nickel–graphite (Ni–G) and copper–graphite (Cu–G) coatings on titanium bipolar plates. This study investigates the effect of different graphite contents on the phase composition, microstructure, corrosion resistance, and electrical conductivity of the coatings. The results show that higher graphite content leads to better performance. The potentiostatic corrosion current densities of the Ni–G and Cu–G coated bipolar plates are 1.05 × 10⁻⁴ A·cm⁻² and 0.91 × 10⁻⁴ A·cm⁻², respectively. Similarly, the ICR values of the coated bipolar plates are 25.2 mΩ·cm⁻² and 38.9 mΩ·cm⁻² before and after cathodic polarization for Ni–G, and 17.4 mΩ·cm⁻² and 21.2 mΩ·cm⁻² for Cu–G. These results suggest that metal–graphite coatings deposited by APS represent a viable strategy for titanium bipolar plates.