Yongping Pan

Yongping Pan, Lin Pan, Haoyong Yu

Composite adaptive control (CAC) that integrates direct and indirect adaptive control techniques can achieve smaller tracking errors and faster parameter convergence compared with direct and indirect adaptive control techniques. However, the condition of persistent excitation (PE) still has to be satisfied to guarantee parameter convergence in CAC. This paper proposes a novel model reference composite learning control (MRCLC) strategy for a class of affine nonlinear systems with parametric uncertainties to guarantee parameter convergence without the PE condition. In the composite learning, an integral during a moving-time window is utilized to construct a prediction error, a linear filter is applied to alleviate the derivation of plant states, and both the tracking error and the prediction error are applied to update parametric estimates. It is proven that the closed-loop system achieves global exponential-like stability under interval excitation rather than PE of regression functions. The effectiveness of the proposed MRCLC has been verified by the application to an inverted pendulum control problem.

MD. Meftahul Ferdaus, Mahardhika Pratama, Sreenatha G Anavatti et al.

At recent times, with the incremental demand of the fully autonomous system, a huge research interest is observed in learning machine based intelligent, self-organizing, and evolving controller. In this work, a new evolving and self-organizing controller namely Generic-controller, G-controller, is proposed. The G-controller that works in the fully online mode with very minor expert domain knowledge is developed by incorporating the sliding model control, SMC, theory based learning algorithm with an advanced incremental learning machine namely Generic Evolving Neuro-Fuzzy Inference System , GENEFIS. The controller starts operating from scratch with an empty set of fuzzy rules, and therefore, no offline training is required. To cope with the plant vulnerable behavior, the controller can add, or prune the rules on demand. Control law and adaptation laws for the consequents are derived from the SMC algorithm to establish a stable closed-loop system, where the stability of the G-controller is guaranteed using the Lyapunov function. The uniform asymptotic convergence of tracking error to zero is witnessed through the implication of an auxiliary robustifying control term. In addition, the implementation of the multivariate Gaussian function helps the controller to handle the non-axis parallel data from the plant and consequently enhances the robustness against the uncertainties and environmental perturbations. Finally, the controller performance has been evaluated by observing the tracking performance in controlling simulated plants of unmanned aerial vehicle namely bio-inspired flapping wing micro air vehicle BIFW MAV and hexacopter for a variety of trajectories.

Yansong Li, Kai Hu, Kohei Nakajima et al.

Echo state network (ESN), a kind of recurrent neural networks, consists of a fixed reservoir in which neurons are connected randomly and recursively and obtains the desired output only by training output connection weights. First-order reduced and controlled error (FORCE) learning is an online supervised training approach that can change the chaotic activity of ESNs into specified activity patterns. This paper proposes a composite FORCE learning method based on recursive least squares to train ESNs whose initial activity is spontaneously chaotic, where a composite learning technique featured by dynamic regressor extension and memory data exploitation is applied to enhance parameter convergence. The proposed method is applied to a benchmark problem about predicting chaotic time series generated by the Mackey-Glass system, and numerical results have shown that it significantly improves learning and prediction performances compared with existing methods.

Tian Shi, Shihua Li, Changyun Wen et al.

This paper proposes a composite learning backstepping control (CLBC) strategy based on modular backstepping and high-order tuners to achieve closed-loop exponential stability without high-gain feedback and PE. A novel composite learning mechanism that maximizes the staged exciting strength is designed for parameter estimation, enabling parameter convergence under interval excitation (IE) or even partial IE, which is strictly weaker than PE. An extra prediction error is employed in the adaptive law to ensure the transient performance without high-gain feedback. Simulations have demonstrated the effectiveness and superiority of the proposed method in both parameter estimation and control compared to state-of-the-art methods.

Xinyu Jia, Wenxin Wang, Jun Yang et al.

This paper proposes a task-oriented model predictive control (ToMPC) framework for safe and efficient robotic manipulation in open workspaces. The framework unifies collision-free motion and robot-environment interaction to address diverse scenarios. Additionally, it introduces task-oriented obstacle avoidance that leverages kinematic redundancy to enhance manipulation efficiency in obstructed environments. This complex optimization problem is solved by the alternating direction method of multipliers (ADMM), which decomposes the problem into two subproblems tackled by differential dynamic programming (DDP) and quadratic programming (QP), respectively. The effectiveness of this approach is validated in simulation and hardware experiments on a Franka Panda robotic manipulator. Results demonstrate that the framework can plan motion and/or force trajectories in real time, maximize the manipulation range while avoiding obstacles, and strictly adhere to safety-related hard constraints.