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This paper introduces a cable-driven robot for upper-limb rehabilitation. Kinematic and dynamic of this rehabilitation robot is analyzed. A sliding mode controller combined with a nonlinear disturbance observer is proposed to control this robot in the presence of disturbances. Simulation is carried out to prove the effectiveness of the proposed control scheme, and the results of the proposed controller...
In this work, we consider the labeled multi-robot planning problem. In this paradigm, a team of robots at fixed start positions must navigate to pre-specified and noninterchangable goal positions. While many algorithms have been proposed for finding optimal solutions to this problem, most methods assume that the robots are kinematic agents, whereas in reality, robots often have high-order dynamics...
In this article we present a symbolic closed-form matrix formulation to obtain the dynamic equations of branched articulated multibody systems (AMS)s. The proposed approach uses geometric mechanics based on Screw Theory and Lie groups. Both Lagrange's and Newton-Euler's equation of motion are derived. Furthermore, the structure of the proposed set of geometric equations holds the intrinsic robot parameters...
In the paper new control algorithm for skid-steering mobile platforms has been presented. This control law is based on mathematical model of such object. In the model it has been assumed that wheels of the skid-steering platform are not coupled by tracks and that they can move without some slipping effects, namely with lack of longitudinal slipping of selected wheels and lack of lateral slipping of...
The Inverse Kinematics (IK) algorithms implemented in the open-source Orocos Kinematics and Dynamics Library (KDL) are arguably the most widely-used generic IK solvers worldwide. However, KDL's only joint-limit-constrained IK implementation, a pseudoinverse Jacobian IK solver, repeatedly exhibits false-negative failures on various humanoid platforms. In order to find a better IK solver for generic...
The identification of the dynamic model of a robotic manipulator represents a fundamental step for designing high performance model-based controllers. Despite the huge number of works presented on this topic, the symbolic dynamic model reduction (i.e., the identification of the set of parameters observable through the measure of joint torques and positions) still remain a challenging task, characterized...
This paper deals with motion planning problems for spherical rolling robots driven by a two degree of freedom pendulum. A full dynamic model for this system is first introduced. Then, assuming that the contact path is specified and the sphere moves in pure rolling mode, the full dynamic model is reduced by imposing virtual constraints. A timing control law, based on the Beta function, for tracing...
This paper presents a recursive and parallel formulation for the dynamics simulation of large articulated robotic systems based on the Hamilton's canonical equations. Although Hamilton's canonical equations exhibit many advantageous features compared to their acceleration based counterparts, it appears that there is a lack of dedicated parallel algorithms for multi-rigid body dynamics simulation based...
This paper reformulates an optimization algorithm previously presented in continuous-time to one using structured integration and structured linearization methods from discrete mechanics. The objective is to synthesize trajectories for dynamic robotic systems that improve the estimation of model parameters by using a metric on Fisher information in a nonlinear projection-based trajectory optimization...
Personal robots need to manipulate a variety of articulated mechanisms as part of day-to-day tasks. These tasks are often specific, goal-driven, and permit very little bootstrap time for learning the articulation type. In this work, we address the problem of purposefully manipulating an articulated object, with uncertainty in the type of articulation. To this end, we provide two primary contributions:...
The curvature control problem for a class of hyper-redundant robot arms with continuum elements characterized by an elastic backbone system is analyzed. The main parameters of the arm shape as curvature and curvature gradient are estimated. The stability analysis and the resulting controllers are obtained using the concept of boundary geometric control and a weighted state control methods. The proposed...
There are many applications where topology constraints are useful in trajectory generation for mobile robots. In this paper we present a method to generate an optimal trajectory restricted to a particular homology class. The optimality is achieved by formulating the trajectory generation problem as a Mixed-Integer Quadratic Program (MIQP). We introduce binary variables that not only encode information...
The paper deals with the motion planning for a spherical rolling robot actuated by internal rotors that are placed on orthogonal axes. It is shown that if the robot is actuated by three rotors, any feasible kinematic trajectory is dynamically realizable. For the case of two rotors the conditions of controllability and dynamic realizability of a feasible kinematic trajectory are established. It is...
We address the problem of developing feedback controllers for a group of robots with second-order dynamics in an obstacle-filled, D-dimensional environment. Our control algorithm takes into account communication constraints, obstacle avoidance, and inter-robot collision avoidance, by synthesizing a piecewise smooth vector field for safe navigation. First, the feasible free joint configuration space...
This paper uses the continuation method as a guideline to address the trajectory planning problem in robotic systems. It is assumed that the robotic system can be represented by a control affine system with output. From the homotopy map a partial differential equation is derived involving the control system and its variational system, whose solution yields a 1-parameter family of control functions...
This paper proposes a balance control algorithm which uses Zero Moment Point (ZMP) in order to improve the mobility of leg-wheel hybrid structures on hard, flat surfaces. The algorithm generates balancing leg motions which continuously adjust the contact points to allow the geometric center of the contact area to follow ZMP. During our simulation of a balance control system which uses Individual Joint...
We propose a scheme to deal simultaneously with local motion planning and dynamic control of redundant cooperative robots subject to holonomic, posture and loop-closure constraints. In contrast to previous contributions, an iterative method, that glue together the problem of kinematic motion planning with dynamic control, generates the sequence of feasible collision-free motions by combining in a...
The authors present a new algorithm to compute the forward Dynamics of n degrees of freedom serial kinematic chains, which is faster than the classical approaches. This algorithm was created rewriting the Lagrange equation in terms of lines and points in the framework of conformal geometric algebra, which allows having a new equation to compute the dynamics with less number of products. This algorithm...
Modern robotic systems perform elaborate tasks in a complicated environment and have close interactions with humans. Therefore fault detection and isolation (FDI) systems must be carefully designed and implemented on robots in order to guarantee safe and reliable operations. In addition, many high performance robotic controllers require full state feedback; hence it is essential to implement state...
For target tracking in Interference Environments of cognitive radar problem, Extended Karman, Particle filter algorithms etc. are generally used to be regarded as usual solutions to state estimation. Many techniques have been developed to improve performance of target tracking. In this paper, we set the structure and key features of target's tracking design for cognitive radar, and newly propose cognitive...
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