Adaptive fault‐tolerant control of mobile robots with actuator faults and unknown parameters

Faults Diagnosis in Robot Systems: A Review

“…According to the logical output (zero or one), the signal is considered as a fault when it is equal to one and normal when equal to zero. In [24], a study of fault tolerant control is presented for a mobile robot to detect and control the faults happened in the actuators of wheels and unknown robot's parameters. These faults lead to a path that is untruly, or with a wrong trajectory because of the friction factors and the driving gain in the used two-independent wheeled mobile rotor.…”

Observer‐based neural adaptive control of a platoon of autonomous tractor–trailer vehicles with uncertain dynamics

“…Among them, one attractive solution is the virtual leader‐following in which a virtual leader determines directions, speeds, and accelerations of all following vehicles, and all robots in the convoy respond to the leader vehicle's action. WMRs [4–6] are classified into several categories based on their mobility and steerability where car‐like ones and autonomous tractor–trailer WMRs (TTWMRs) are not paid attention enough in the literature [7–9]. Unfortunately, few controllers are proposed for the formation of such multibody vehicles [9] in recent years and most of the presented controllers are devoted to a single TTWMR.…”

“…Then, a saturated filtered error variable is defined to design our controller while bounding the unconstrained errors as well. After a deep literature review including [1–22], the main novelties of the proposed controller are listed as follows: (1) This is the first attempt to design a tracking controller for a convoy‐like motion of multiple off‐axle hitching tractor–trailers. (2) The proposed controller does not require the velocity and acceleration measurements in real‐time. (3) The actuator saturation risk is reduced by considering a hyperbolic tangent function and projection‐type neural adaptive rules. (4) The collisions between successive tractor–trailers are avoided by constraining the relative distance error. (5) The consecutive vehicles' connectivity is ensured by considering the limited communication range of vehicle transmitter–receivers. (6) The possible singularity of the tracking controller is avoided by constraining the relative angle error. (7) The desired prescribed transient and steady‐state performance criteria are guaranteed in advance. (8) All types of TTWMR model uncertainties are compensated by neural adaptive robust techniques. …”

Adaptive fuzzy fault‐tolerant control for non‐linear systems under actuator and sensor faults: the practical fixed‐time stability

“…After long‐term work, the system components, e.g., actuator, sensor and so on, may suffer from wear and ageing phenomena, and lead to some undesirable faults [17, 18]. These phenomena often occur in some practical control systems, such as satellite attitude system [19], mobile robots [20], quadrotor model [21] and so on. Those abrupt faults may deteriorate the system performance and even result in catastrophic accidents [22, 23].…”