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This paper presents adaptive time-delay control (TDC) with a supervising switching technique (SST) for controlling robot manipulators. Two adaptive techniques are used to enhance the TDC. The control gain of TDC is adaptively tuned using a class of Nussbaum functions. With Nussbaum functions, compared with conventional TDC using a constant gain, the proposed control using Nussbaum functions can deal with inertia parameter variations due to the movement of a robot manipulator. The SST is used to deal with discontinuous disturbances. The proposed control is model-free, highly accurate, robust and adaptive. [ABSTRACT FROM AUTHOR]

This paper presents an enhanced time-delay controller (TDC) for the position control of an autonomous underwater vehicle (AUV) under disturbances. A conventional TDC performs well when the involved data acquisition rate is fast. However, in AUV control applications that use a Doppler velocity log (DVL) navigation system, we cannot keep the data acquisition rate sufficiently fast because a DVL sensor generally supplies data at a slow acquisition rate, which degrades the performance of the TDC. To overcome this problem, we propose an integral sliding-mode controller to be supplemented to the conventional TDC to improve the control precision even if the DVL navigation system is in operation. The proposed controller is computationally simple and robust to unmodeled dynamics and disturbances. We performed computer simulations and experiments with the Cyclops AUV to demonstrate the validity of the proposed controller. [ABSTRACT FROM PUBLISHER]

Time-delay control (TDC) has been widely used to control various systems thanks to its simplicity and robustness. The control distribution matrix of TDC is assumed to be constant and tuned heuristically. However, the constant TDC control gain could degrade the system control performance and even cause the closed-loop system to become unstable when the system parameters are substantially changing, resulting in the violation of the stability criterion of TDC. We propose an algorithm for automatic tuning of the TDC gain in order to guarantee stability by using a modified Nussbaum function. Thus, the closed-loop system controlled by TDC with the modified Nussbaum function is proven to be semi-globally uniformly ultimately bounded. The auto-tuned gain satisfies the stability criterion of TDC and the proposed method can widen the range of implementable dynamic systems. Simulations are conducted to verify the simplicity, robustness, and guaranteed stability by auto-tuning of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a robust path-following control method of a kinematic mobile robot system subject to bounded angular velocity error. The angular velocity error usually arises from imperfect performance of the dynamic control system. Given a kinematic model of the mobile robot system with bounded angular velocity error, we present a stable and robust path-following controller which is based on the sliding mode control technique and prove that the path-following errors (the lateral distance and orientation error) are ultimately bounded. In addition, the safety margin of the lateral distance error is defined, which is useful for higher-level path-planning tasks. The feasibility of the proposed controller has been demonstrated through simulation tests. [ABSTRACT FROM AUTHOR]