This article presents a novel method for quadrotor trajectory control utilizing cascade control and model predictive control (MPC). The proposed approach divides the control problem into a linear position controller, employing linear MPC with convex quadratic programming, and a nonlinear attitude controller, utilizing deep neural network-based MPC. Addressing the computational load challenges associated with online control, the hardware-in-the-loop (HIL) controller is tested to demonstrate its effectiveness in ensuring fast processing and suitability for online control. The stability of the proposed control strategies is analyzed, and simulation results using the HIL system validate the accurate tracking of desired trajectories. The findings highlight the functionality, reliability, and potential of the proposed approach for real-time applications in quadrotor control.

There has been significant attention towards autonomous vehicles (AVs) for the past few years which could be because of widespread use of these types of vehicles in the societies. Many challenges such as safety, reliability, liability, privacy, and cybersecurity are still being investigated by scientists in order to ensure a safer driving experience for the drivers. In this paper, different approaches are analyzed to examine these issues and the emerging responses to them regarding legal and ethical aspects. The present study shows that there are still many open problems in these areas and governments have not yet offered a solution to address them. Therefore, more research needs to be done to address the existing safety and security challenges.

Heavy object manipulation by wheeled mobile manipulators may lead to serious consequences such as postural instability, and this necessitates dynamically stable planning based on systematic analysis to better predict and eliminate the possibility of toppling down. In the present study, stable motion planning is investigated for wheeled mobile manipulators during heavy object manipulation tasks. It is assumed that the initial and final poses of a heavy payload are specified. Based on these known postures of the payload two proper configurations for robotic system is defined. Then, between these two initial and final poses, appropriate trajectories for multiple robotic arms relative to the moving base are planned without considering the postural stability of the system. Next, motion of the moving base is planned so that the stability of the overall system is guaranteed while its predetermined initial and final positions and velocities are fulfilled. To this end, the problem of stable planning is solved as an optimization problem. A proper cost function is considered, to be minimized, which is a measure of the control effort to be used for the platform motion. Moreover, using the new dynamic postural Moment-Height Stability (MHS) measure, a constraint denoting the system dynamic stability is derived and satisfied. The proposed planning approach is applied to move a heavy object with a wheeled robotic system that consists of two manipulators, where the obtained results reveal a stable optimal motion besides satisfaction of various practical aspects.

In this study, kinematics design, dynamics modeling and verification of a compounded serial-parallel wheeled mobile robot is elaborated. The proposed novel kinematic structure is best suited to fulfill stable motion of the robotic system when handling heavy objects by manipulators mounted on mobile platforms. The proposed system is made of a differentially-driven wheeled platform, a planar parallel manipulator, which is called here as Star-Triangle (ST) mechanism, and a serial Puma-type manipulator arm. The suggested structure adopts the advantages of both serial and parallel robots, to move the base point of the serial robot with respect to the mobile platform to fulfill the system stability after grasping heavy objects. In order to investigate the comprehensive kinematics model of the robot, after introducing its novel structure it is divided into three modules, i.e. a mobile platform, a parallel ST mechanism, and a serial robot. Next, a closed-form dynamics model is derived for the whole hybrid system based on a combined Newton-Euler and Lagrange formulation. The proposed method presents the mutual dynamic interaction wrenches between the integrated platform and the serial manipulator which can be exploited for the tip-over stability analysis of the mobile robotic system. Then, to verify the obtained mathematical model, several benchmark actuating inputs are applied to the model and the system responses are analyzed.

Field Robots are machines that work in unstructured environments. Handling the mobility performance requirements of a challenging rough terrain makes a suspended wheeled mobile robot (SWMR), with multiple dexterous manipulators, an appropriate field robot design. In this study, first a general systematic procedure for dynamics modeling of such complicated systems is presented based on application of Newton-Euler's formulation for a chain of rigid bodies. Then, to verify the obtained dynamics model, another model for the considered system has been developed using ADAMS simulation software. Comparison between the results obtained from these two models confirms the thoroughness of the proposed analytical model. The presented approach can provide the interaction wrench(es) between the mobile base and the mounted arm(s). Next, using the obtained dynamics, the tip-over stability of such systems will be investigated. To this end, the new dynamic tip-over Moment- Height Stability (MHS) measure will be extended for suspended wheeled mobile robotic systems. Proposing the concept of virtual structure, the obtained planar model of SWMR has been employed to evaluate the behavior of the system on rough terrain in terms of its stability. Therefore the presented model and the MHS measure can be employed for stable planning and model-based control of autonomous SWMR during object manipulation tasks.

Mobile machines equipped with manipulator arm(s) are being increasingly used in a variety of areas of industry. When these mobile utilities perform fast maneuvers, move over rough terrain, manipulate heavy work pieces, or interact large wrenches with their environment, they may go unstable and overturn. Therefore, safety and efficiency of such systems can be improved with a reliable stability recognition metric. For on-line applications, such tip-over stability measure should be computationally simple which makes its presentation a challenging task. In this study, various dynamic stability measures are investigated and compared with each other in terms of their reliability and computational complexity. Then, a new reliable and efficient metric named as Moment-Height Stability (MHS) measure is introduced for mobile manipulators. The proposed metric is a physically meaningful and reliable measure while it contains low computational burden. The MHS measure can be exploited successfully for wheeled mobile manipulators containing single or multiple arms. Besides, by some minor modifications the MHS measure can be also employed for the case of legged locomotion. Also, the proposed MHS measure may be extended for the case of suspended mobile manipulator on rough terrains. Several case studies are presented to reveal the effectiveness of the new MHS measure compared to the main previous measures.