Lane Keeping System Based On Electric Steering

With rapid development of automobile technology, Lane Keeping System(LKS) is playing an increasingly critical role in the field of active safetytechnology of vehicles. LKS based on Electric Steering (ES) has a simplestructure and a small number of components, so it’s strongly practical and easyto promote. For different characteristics and requirements between ElectricSteering System (ESS) and LKS, overall structure of LKS based on ES was builtin this paper and research of related control algorithm including coordinatedcontrol was done.Hierarchical control structure of LKS based on ES has been proposed inthis paper. The upper layer is lane keeping coordinated control layer, whichdetermines whether there is danger of lane departure according to TLC anddetermines driver’s operating status according to torque signal, then lanekeeping coordinated control command is formulated according to lane departureand driver’s operating information; the middle layer is active steering and powersteering control layer, active steering and power steering commands areformulated according to command formulated by the upper layer, in whichactive steering is angle closed-loop control and power steering is current closedloop control; the lower layer is hardware implementation layer, active steeringand power steering commands are performed by ESS.In order to verify lane keeping coordinated control strategy designed in thispaper, simulation platform of LKS based on ES was designed. The simulationmodel includes driver model, vehicle model, tire model, ESS model, TLCcalculation model and auxiliary mode judgment model. Six simulationconditions based on different velocities and lane centerline trajectories weredesigned. Simulations under different conditions have been done. Trend of TLC,steering wheel angle, motor voltage and trajectory of vehicle centroid have beenanalyzed during simulation processes. Simulation results show that lane keepingcoordinated control algorithms designed in this paper have good coordinatedcontrol effects and can meet expected design goals. Experimental platform vehicle has been transformed focused on ESS basedon simulation. Motor drive circuit and corresponding RCP model based ondSPACE system were developed. Basic functions of active steering and powersteering are verified through active steering and power steering experimentsbased on this. In order to verify control effects of lane keeping coordinatedcontrol algorithms designed here, hardware-in-the-loop experiments and vehicleroad experiments have been done. Experimental results show that controlalgorithms designed in this paper can coordinate the relationship between lanekeeping executive component and conventional power steering component andcan keep the vehicle in the lane at the same time, thus improve safety whiledriving.