In this article, the consensus problem of nonlinear multiagent systems (MASs) with time-varying communication delays (TVCDs) is addressed by proposing a novel nonfragile memory-based sampled-data control approach. Different from the existing sampled-data control schemes, an improved memory-based proportional derivative like a sampled-data control scheme based on the information of neighbors is proposed. Besides, considering the inaccuracy and perturbation of controller, a nonfragile control method is also adopted to design the controller. Then, instead of the general quadratic type of the Lyapunov–Krasovskii functional, a delay-product-type quadratic is presented by taking full advantage of the information of TVCDs, and the positive definite constraint in the entire time domain is weakened to the sampled instants on account of adopting the two-sided looped-functional approach. Furthermore, less-conservative consensus criteria for MASs are developed. By solving linear matrix inequalities, the desired control gain matrices and larger sampled-data periods are achieved. Finally, illustrative examples are employed to demonstrate the effectiveness of the designed control strategy.

The distributed drive electric platform is extensively utilized in special-purpose unmanned ground vehicles due to exceptional maneuverability and obstacle navigation capabilities in off-road environments. This paper comes up with an energy-saving torque allocation strategy to enhance path-tracking precision and energy utilization efficiency. For mitigating the conflict between path tracking and energy management in torque distribution, a hierarchical control framework is proposed for total demanding torque control, inter-axle torque distribution, and inter-wheel torque allocation. The inter-axle torque distribution is determined by considering the total motors efficiency region reflection to enhance energy conversion efficiency. This approach ensures that torque is allocated to maximize energy conversion efficiency. Besides, the inter-wheel torque allocation is optimized using quadratic programming, considering factors such as tire vertical load distribution and path tracking error. By decoupling these control aspects, the proposed framework ensures optimal performance in both path tracking and energy management. In contrast, a traditional torque allocation method is also presented. Finally, the simulation experiments are conducted in MATLAB/Simulink and TruckSim with specialized off-road working cycles. The numerical experiment results demonstrate that the presented strategy considerably ensures an optimal torque allocation for path tracking while simultaneously enhances the overall efficiency of the distributed drive system compared with the conventional approach.

Unstructured off-road environments with complex terrain obstacles and pavement properties bring obvious challenges for special purpose autonomous vehicle control. A cascade direct yaw moment control strategy (CDYC), which contains a main loop and a servo loop, is proposed to enhance the accuracy and stability of an independent eight in-wheel motor-driven autonomous vehicle with rear-wheel steering (8WD/RWS). In the main loop, double PID controllers are designed to generate the desired drive moment and yaw rate. In the servo loop, the quadratic programming (QP) algorithm with the tire force boundaries optimally allocates the demanded yaw moment to individual wheel torques. The 8WD/RWS prototype is virtually established using TruckSim and serves as the control object for co-simulation. The proposed cascade controller is verified by simulations in customized off-road driving scenarios. The simulation results show that the proposed control architecture can effectively enhance the path-tracking ability and handling stability of the 8WD/RWS, as to ensure the maneuverability and control stability under extreme off-road conditions.

Flight Control Development and Test for an Unconventional VTOL UAV | InTechOpen, Published on: 2016-09-07. Authors: Yang Wang, Changle Xiang, Yue Ma, et