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This paper introduces a two-tier feedback control law for the path tracking of a mobile robot equipped with N on-axle trailers. Initially, through a recursive design process, the curvature-tracking challenge is converted into stabilizing the joint angles at predefined reference values. This design approach is straightforward and can be easily extended to configurations with multiple trailers. Using input-to-state stability analysis, we demonstrate the asymptotic stability of the closed-loop system, which is structured in cascade form. Furthermore, we reformulate the path-tracking problem as a curvature-planning challenge and propose an algorithm to determine the desired curvature for the tail trailer. The simulation results validate the effectiveness of this novel algorithm in truck-trailer systems. [ABSTRACT FROM AUTHOR]

The hybrid space of robots is divided into task space and joint space, with task space focused on trajectory-tracking accuracy, while joint space considers dynamic responsiveness and synchronization. Therefore, the robot-motion control systems need to effectively integrate both aspects, ensuring precision in task trajectory while promptly responding to unforeseen environmental events. Hence, this paper proposes an online trajectory-generation method for robots in both joint and task spaces. In task space, a planning approach is presented for high-precision NURBS curves. The global NURBS curve is segmented into several rational Bezier curves, establishing local coordinate systems for control points. This ensures that all local control points meet the chord error constraint, guaranteeing trajectory accuracy. To address the feed rate dynamic planning issue for segmented curves, an improved online S-shape feed-rate scheduling framework is introduced. This framework dynamically adjusts the current execution speed to meet task requirements. In joint space, an offline velocity planning based on a time synchronization scheme and a multi-dimensional synchronization technique based on the principle of spatial-coordinate system projection are proposed. Building upon the offline scheme, it allows for the modification of the target state for any sub-dimension during the motion process, with the remaining dimensions adapting accordingly. Simulation and experimentation demonstrate that the two proposed online trajectory generations for robot motion spaces, while ensuring task trajectory accuracy, effectively handle external unexpected events. They ensure joint synchronization and smoothness, carrying significant practical implications and application value for the stability of robot systems. [ABSTRACT FROM AUTHOR]

Skid-steering control is commonly used in mobile robots, but its application to climbing manipulation-oriented robots (CMo-R) requires further development. This study proposes an adaptive skid-steering control strategy using an integral terminal sliding mode controller (ITSMC) to improve the climbing maneuverability of four-wheeled CMo-Rs on unknown inclined surfaces. The control law is developed using both kinematics and dynamics models, considering slipping effects to reduce slippage during 3D motion. A slip estimation and ITSMC-based adaptive control algorithm are introduced to enhance tracking accuracy in complex 3D environments. The proposed approach is compared to traditional PID and adaptive kinematic controllers through simulations and experiments. Results show that the proposed method outperforms the others in terms of tracking performance and robustness, especially for navigating horizontal, inclined, and vertical surfaces. This work provides a new control strategy for CMo-Rs, contributing to the feasibility and stability of future climbing manipulation applications. • An adaptive skid-steering decoupling control strategy using an integral terminal sliding mode controller (ITSMC) to enhance the climbing performance of the four-wheel climbing manipulation-oriented robot (CMo-R) on unknown inclined surfaces. • A control law based on the kinematics and dynamics model of CMo-R considering the slip phenomenon during the three-dimensional movement on uncertain surfaces. • The tracking accuracy improvement of CMo-R in complex unknown inclined surfaces by proposing the Lyapunov-based slip estimation and the ITSMC-based adaptive control algorithm. [Display omitted] [ABSTRACT FROM AUTHOR]