Research on Virtual Track Train Path-Tracking Control Based on Improved MPC and Hierarchical Framework: A Reconfigurable Approach

Abstract

The virtual track train (VTT) is a new urban public transportation system that adopts all-axle steering and distributed drive. The Super autonomous Rail rapid Transit (SRT), as one of them, adopts a four-module six-axle structure. In response to its crucial problem, its path tracking, this article proposes a reconfigurable dynamic modeling method, which has two parts: a multi-body dynamics model with generalized forces at each module’s center of gravity (CG) as the input, and the CG generalized force model, which expresses the CG generalized forces generated by the wheel control inputs. Then, a path-tracking strategy is proposed based on the improved MPC and hierarchical framework. Firstly, the CG generalized forces of each module required for path tracking were calculated, and then the CG generalized force redistribution was performed and the “virtual axle” method was proposed. Finally, the wheel state of each module was allocated. This strategy reduces the complexity of each layer of the controller and it solves the problem of insufficient actuators in the middle two modules of the SRT. Finally, through a hardware-in-the-loop (HIL) real-time simulation and comparison with different control strategies, the control strategy’s effectiveness, adaptability, and robustness were verified.

Damping Coefficient Optimization for the Articulated System of Virtual Track Trains

“…Virtual track is a target trajectory relative to traditional steel rails, which is achieved through laying magnetic nails on the road or drawing encoded graphics, combined with vehicle visual perception and magnetic induction technology, to achieve the same load-bearing, guiding, and constraint functions as tangible tracks. Virtual track trains utilize path tracking control technology to achieve high-precision autonomous tracking of target paths by controlling the wheel angles of each axle and the driving torque of the drive wheels [4,5]. Virtual track trains have operational characteristics such as dedicated right-of-way, high-speed dragging driving in straight sections (40-70 km/h), i.e., rear axles locking without steering, lowspeed controlled driving in curved sections (10-30 km/h), i.e., full wheel steering, and no emergency lane change.…”

All-Wheel Steering Tracking Control Method for Virtual Rail Trains with Only Interoceptive Sensors

“…FF control is achieved by road curve and FB control uses a proportional-integral (PI) controller based on lateral deviation. Wang [20] proposed a reconfigurable dynamic model of SRT with the relationship between generalized forces and tires. Improved model predictive control (MPC) is designed to allocate generalized forces and steering angles, which are calculated from generalized forces.…”