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In this paper, we propose a novel evolutionary algorithm(EA)-based formation control with collision avoidance for nonholonomic mobile robots. In most conventional approaches, multi-robot formation control problem with collision avoidance can be formulated as a constrained nonlinear optimization problem in model predictive control (MPC) framework. The conventional approaches, therefore, suffer from...
The main purpose of teleoperation in medical usage is to provide technical means to perform a desired task in patient' body. It is important to haptic feedback of sensitive and delicate environment to the surgeon hand's to improve task performance. The Kelvin-Voigt (KV) model for environment, due to physical contradiction is not suitable, but the Hunt-Crossley (HC) model is chosen because of its accuracy...
This paper presents the stability analysis of the reference compensation technique (RCT) of a neural network control scheme (NN) for controlling position of robot manipulators. RCT is known as one of neural network control schemes that compensate for the uncertainties of a robot manipulator. Different from the feedback error learning (FEL) scheme, RCT compensates at the trajectory level so that it...
In this paper a new model-mediated teleoperation framework based on rate-control input is presented. The system facilitates force feedback teleoperation and is inherently robust to severe time delays yet still provides high level of rate/force tracking fidelity. Previously published methods on model-mediated teleoperation are here extended to accept rate commands and use the slave robot's programmed...
This paper proposes a multi-objective strategy, based on the null space control theory in order to guide formation composed by aerial and terrestrial robots. A mathematical representation for a triangular heterogeneous formation is presented considering the constraints imposed by the UGVs into the formation variables. The stability of the controller is analysed using Lyapunov theory and simulation...
Guiding virtual fixtures have been proposed as a method for human-robot co-manipulation. They constrain the motion of the robot to task-relevant trajectories, which enables the human to execute the task more efficiently, accurately and/or ergonomically. When sequences of different tasks must be solved, multiple guiding virtual fixtures are required, and the appropriate guide for the current task must...
In this work we propose a plan repair algorithm designed to be used in a real-life setting for a team of autonomous robots. This algorithm is built on top of a hybrid planner. This planner mixes partial order planning and hierarchical planning. This allows the creation of a plan with temporal flexibility while using human knowledge to improve the search process. Simulation shows that repairing increases...
Dexterous object manipulation with robotic hands (subject to holonomic constraints) usually requires the capacity of fingertips to roll onto the object, which is very difficult to achieve with frictionless point contact model . As an alternative, deformable contact model has been considered based on hemispherical shape end-effector to yield rolling. However, it entails dexterity at the expense of...
Whole-body holding manipulation is effective for carrying the handleless large object. In order to keep the object stability, the dexterous transition motion is necessary. From geometric and physical conditions of object manipulation, we propose the general method of generating the transition graph, which represents the object pose and grasp contact. By searching the path on the graph, the transition...
Dividing the control authority of the slave robot among operators, based on the available information to them and their controlling strategy, is absolutely essential for cooperative teleoperation systems. Although there have been many studies on this, most of the analysis were limited to fixed authority and its effect on stability. None of the research has discussed how to allocate the control authority...
Recent studies revealed that hand gesture-based interfaces can complement therapies for individuals with upper motor impairments and reduce the need of traditional rehabilitation sessions through hospital visits. Unfortunately, existing gesture-based interfaces have been developed without considering the physical limitations of users with motor impairments. An analytic approach was presented in our...
In this paper we exploit Iterative Learning Controllers (ILC) schemes in force adaptation tasks. We propose to encode the control signal with Radial Basis Functions (RBF), which enhances the robustness of the ILC scheme and allows to vary the execution speed of the learned motion. For that a novel control scheme is proposed, which updates the feedforward compensation signals based on current iteration...
This paper presents a teleoperation system for two six-degree-of-freedom ARMin arm rehabilitation skeletons. Two control strategies are presented: unilateral teleoperation, which is realized with proportional-derivative controllers, and bilateral teleoperation, which is realized with compliance control and torque feedback. An empirical procedure for identifying the best control gains of the unilateral...
A robust tracking control problem is considered for an unknown Euler-Lagrange system to track a desired time-varying trajectory. Unknown dynamics including friction effects and impact forces from the environment are considered in the paper. It is challenging to model these two types of uncertain forces for Euler-Lagrange Systems such as robot manipulators and motors. A robust controller with adaptive...
In open normative multi-agent systems, norms are created dynamically. Some of these norms emerge and persist due to their benefits and strength. While other norms emerge for a short period of time, then vanish due to several reasons that lead to loss in their benefit or strength. Each norm of the created ones might have positive, negative, or neutral consequences on the system. Norms decay by society's...
The paper presents the concept and stability analysis of a trajectory-tracking feedback control system for truly N-trailer robots equipped with arbitrary number of trailers interconnected by the non-zero hitching offsets. Thanks to application of the cascaded-like control structure the considered solution is modular and highly scalable with respect to a number of trailers. Formal analysis of the closed-loop...
Iterative learning control was developed for systems that repeat the same task over a finite duration with resetting to the starting point once each execution is complete. The distinguishing feature of this form of control is the use of information from previous executions of the task to update the control signal to be applied on the next execution and thereby sequentially improve performance. Once...
A control algorithm for finite-time tracking of quadrotor is introduced. The algorithm is based on use of feedback linearization method and finite-time output control presented in [17]. In comparison with commonly used in practice control methods like PD-controller the proposed method allows to estimate the first derivatives of the generalized coordinates, that enable to reduce the number of necessary...
The paper presents the development of a measurement system for dynamic stability analysis. The system is composed of an actuation device, that is a robotic platform with four degrees of freedom, and two measurement systems: a force platform, to measure the position of the centre of pressure (COP), and a vision system, to measure the position of the centre of mass (COM). The purpose of the system is...
In designing concentric tube robots, it is often desirable to use curvatures that are as high as possible. However, with high curvatures comes the potential for elastic instabilities. This can be addressed by motion planning or by designing the robot to preclude the possibility of instability. In this paper, we pursue the latter. Our primary contribution is to show that local bifurcation theory can...
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