A triple‐step non‐linear control for path following of autonomous vehicles with uncertain kinematics and dynamics

Fault‐tolerant path‐following control for in‐wheel‐motor‐driven autonomous ground vehicles with differential steering

“…To obtain a tradeoff between performance and stability, the controller gains are set as k 1 = 200, k 2 = 10 and k 3 = 10, and the saturation limit of each in-wheel motor torque is set as 460 Nm. A comparative simulation case using the adaptive triple-step method [27] is presented to highlight the advantage of the proposed fault-tolerant path-following method under the safe mode of the front-wheel steering system (stuck fault at the vehicle level). Note that the controller in [27] is based on the adaptive triple-step method to achieve the coordinated lateral and longitudinal path following in the fault-free case.…”

“…A comparative simulation case using the adaptive triple-step method [27] is presented to highlight the advantage of the proposed fault-tolerant path-following method under the safe mode of the front-wheel steering system (stuck fault at the vehicle level). Note that the controller in [27] is based on the adaptive triple-step method to achieve the coordinated lateral and longitudinal path following in the fault-free case. In the following figures of the simulation results, "FTPFC" and "PFC" stand for the proposed fault-tolerant path-following control approach and the regular path-following control approach [27].…”

“…Note that the controller in [27] is based on the adaptive triple-step method to achieve the coordinated lateral and longitudinal path following in the fault-free case. In the following figures of the simulation results, "FTPFC" and "PFC" stand for the proposed fault-tolerant path-following control approach and the regular path-following control approach [27].…”

“…Note that the condition for which y e tends to zero is thaṫ V 2 = −k 2 2 e < 0 with k 2 > 0. Thus, the desired reference V sr can be determined by V sr = −k 2 e + V cos e (27) and the error dynamics of y e is governed bẏ e = V s − V cos e = −k 2 e − V sr + V s (28) and the derivative oḟe is further derived as…”

“…Therefore, this paper proposes a fault-tolerant path-following controller for IWM-AGVs with differential steering. One of the control algorithms that may provide inspiration in the vehicle control field is the adaptive triple-step nonlinear approach [26,27], in which the controller design procedure is simplified as steady-state control, reference-variation-based control and tracking error feedback control, and the adaptive update law covers all the system process parameters. Nevertheless, the fault and/or failure in the steering system are not taken into account and may lead to system instability.…”