This paper presents the constraint dynamic modelling of a six-link elbow-bracing manipulator. This system is kinematically redundant when it is asked to perform spatial trajectory tracking tasks. Hence the extra degrees of freedom (DOFs) can be used to assign additional motion such as constraint forces control without violating end-effect's functions, which can improve the manipulator's performance such as minimizing energy requirements. Since the control of the constraint forces will not affect the end-effect's position, the hybrid force and position control method is proposed. The control scheme consists of two terms: constraint forces control with the incorporation of proportional (p) controller and trajectory tracking control. In addition, the motion equations of motors are incorporated into the constraint dynamics of the system. So that the energy consumption can be calculated by integrating the product of the voltage and current. This study is based on our previous works, which can achieve the control of three constraint forces. Finally, simulation experiments along with comparative studies of previous works such as: with no constraint force and one constraint force are conducted. The results show that the proposed method achieves prior energy-efficient performance and tracking accuracy.
Physical models of musical instruments offer an interesting tradeoff between computational efficiency and perceptual fidelity. Yet, they depend on a multidimensional space of user-defined parameters whose exploration by trial and error is impractical. Our article addresses this issue by combining two ideas: query by example and gestural control. Prior publications have presented these ideas separately but never in conjunction. On one hand, we train a deep neural network to identify the resonator parameters of a percussion synthesizer from a single audio example via an original method named perceptual-neural-physical sound matching (PNP). On the other hand, we map these parameters to knobs in a digital controller and configure a musical touchpad with MIDI polyphonic expression. Hence, we propose a multisensory interface between human and machine: it integrates haptic and sonic information and produces new sounds in real time as well as visual feedback on the percussive touchpad. We demonstrate the interest of this new kind of multisensory control via a musical game in which participants collaborate with the machine in order to imitate the sound of an unknown percussive instrument as quickly as possible. Our findings show the challenge and promise of future research in musical "Human-AI parternships".
As the hybrid system consists of 3-DOFs series mechanism and the 6-DOFs parallel mechanism has been widely used to transport the personnel maintenance or materials into the offshore wind turbine platform and offshore oil platform, it is important to maintain the stability of gangway in the presence of ocean wave to ensure the safety of maintenance personnel. In this paper, to compensate the ocean wave disturbance, the task priority method is presented. Moreover, the kinematic redundancy and motion constraints of the hybrid mechanism are taken into consideration. Firstly, we establish the kinematics equation based on the designed model of the hybrid mechanism. And the Jacobian matrix and its pseudo inverse of hybrid mechanism in the task space is derived. The multi-task priority hybrid organization planning is established in the form of pseudo-inverse solution. Moreover, the framework based on the mechanism end motion, joint limit and avoiding singular tasks, designed a system coordinated motion planning algorithm to reasonably solves the redundance while maximizing the space allocation problem. Finally, the simulation experiment is carried out and the results demonstrate the effectiveness of the proposed method.
This paper presents the detailed modeling and simulation of the dynamic coupling between an autonomous underwater vehicle (AUV) and a manipulator. The modeling processes are described with the incorporation of the most dominating hydrodynamic effects such as added mass, lift and drag forces. The hydrodynamic coefficients are derived using strip theory and are adjusted according to dynamical similarity. A fuzzy decoupling controller (FDC) is proposed for an autonomous underwater vehicle-manipulator system (UVMS) which consists of two subsystems, an underwater vehicle and a manipulator. The proposed controller uses a fuzzy algorithm (FA) to adaptively tune the gain matrix of the error function (EF). The EF is described by the integral sliding surface function. This technique allows the off-diagonal elements developed for decoupling the system to be incorporated in the gain matrix. Tracing the FA and EF back to the principle of feedback linearization, one further obtains evidence about the decoupling and stability of the system. Moreover, a desired trajectory with the consideration of the dynamic coupling of the AUV is designed to reduce the thruster forces and manipulator's torques. This technique provides high performance in terms of tracking error norms and expended energy norms. A major contribution of this study is that it adopts the off-diagonal elements to exploit the dynamic coupling between the degrees of freedom of the subsystem and the dynamic coupling between the two subsystems. Simulation results demonstrate the effectiveness and robustness of the proposed technique in the presence of parameter uncertainties and external disturbances.
The problem focusing on heading motion control of remotely operated underwater vehicle (ROV) is studied and adaptive integral back-stepping controller with nonlinear disturbance observer (NDO) is proposed in this paper. Taking advantage of the ability that nonlinear disturbance observer can estimate uncertainties and external disturbance exactly, combined back-stepping method, we can greatly reduce the influence of parameter uncertainties and external disturbances on the ROV system; meanwhile, in order to enhance the robust performance of the system, integral terms are added into the feedback loop; finally, adaptive item is added in order to estimate residual uncertainties and interference. Design process of the controller for ROV is described in detail; using Lyapunov stability criterion, global asymptotic stability and tracking error convergence are proved. Simulation experiments have shown that the controller can overcome and estimate factors such as external disturbance and model uncertainties, the system is able to track the desired trajectory accurately and has good robust performance.
This paper presents new motion planning and robust coordinated control schemes for trajectory tracking of the underwater vehicle-manipulator system (UVMS) subjected to model uncertainties, time-varying external disturbances, payload and sensory noises. A redundancy resolution technique with a new secondary task and nonlinear function is proposed to generate trajectories for the vehicle and manipulator. In this way, the vehicle attitude and manipulator position are aligned in such a way that the interactive forces are reduced. To resist sensory measurement noises, an extended Kalman filter (EKF) is utilized to estimate the UVMS states. Using these estimates, a tracking controller based on feedback Linearization with both the joint-space and task-space tracking errors is proposed. Moreover, the inertial delay control (IDC) is incorporated in the proposed control scheme to estimate the lumped uncertainties and disturbances. In addition, a fuzzy compensator based on these estimates via IDC is introduced for reducing the undesired effects of perturbations. Trajectory tracking tasks on a five-degrees-of-freedom (5-DOF) underwater vehicle equipped with a 3-DOF manipulator are numerically simulated. The comparative results demonstrate the performance of the proposed controller in terms of tracking errors, energy consumption and robustness against uncertainties and disturbances.
The underwater vehicle manipulator system (UVM-S) plays a vital role in ocean exploration. However, the system's parametric uncertainty and external disturbance increase the difficulty in designing an appropiate controller. In this paper, the term including parametric uncertainty and external disturbance is estimated using uncertainty and disturbance estimator (UDE). Then, the term is incorporated into a sliding mode control (SMC) method to compensate the uncertainties in hydrodynamic parameters of the vehicle and reject the external disturbance. The proposed UDE-SMC control scheme do not include the switching functin of SMC, which descreases the chattering effect of SMC. In addition, due to the system's kinematic redundancy, the inverse kinematic method based on pseudo-inverse of Jacobian matric is presented to investigate redundancy resolution. The main contribution of this paper is that it presents a simple model-based trajectory tracking controller for UVMS. Finally, the numerical simulations along with the comparative study are conducted. The simulation results illustrate the effectiveness and robustness of the proposed method.
The configuration of elbow-bracing is built by imitating human's handwriting behavior that human can do accurate task with less consumption energy by bracing the elbow or hand on the task. In this paper, first, the motion equation of the elbow-bracing manipulator under constrained condition has been derived. Second, as the consumption energy is calculated based on the voltage and current of the motor, the equation of motion of the motor has been proposed. Then, a control method based on the constraint dynamics of the elbow-bracing manipulator is proposed to simultaneously control constraint force and hand's trajectory and elbow-bracing position in work space. Moreover, we focus on the energy-efficient of the elbow-bracing manipulator, and analysis the factors which have a great effect on the consumption energy, i.e. elbow-bracing position, constraint force. Finally, a simulation experiment for 4-link elbow-bracing manipulator has been conducted to reveal the effectiveness of energy-efficient for the elbow-bracing manipulator and the influence of the above two factors to the energy-efficient.
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