ABSTRACT Independently rotating wheelsets (IRWs) with individually driven wheel motors enable compact low‐floor rail bogies and improved curving, but their running behaviour depends on how accurately traction and differential wheel torques are realised under electrical constraints. This paper presents a constraint‐aware wheel‐torque realisation and allocation framework for IRW bogies using surface‐mounted PMSM traction drives. An integrated control‐oriented model couples linearised lateral–yaw bogie dynamics with a simplified PMSM torque‐response model under field‐oriented control. Feasible current references over constant‐torque and field‐weakening regions are generated using a flux‐map‐based reference generator that maps demanded torque to ‐ and ‐axis current commands whilst accounting for current limits and DC‐link voltage variations. A multi‐input control architecture is adopted: a speed PI loop determines traction demand, an LQ‐servo loop determines yaw‐moment demand and a scaling‐based allocator distributes the demands to four wheel motors with saturation handling. Simulations show simultaneous speed tracking and lateral displacement regulation on straight and curved tracks whilst mitigating hunting‐like oscillations. Experiments on a 1/5‐scale IRW test rig validate stable lateral guidance and torque tracking, with drive currents and voltage utilisation kept within prescribed limits.
Ahn et al. (2026) studied this question.