This article shows that time derivatives of twists and wrenches are indeed screws, in contrast to many classical kinematicians’ believe. Furthermore, it is proven that the “centripetal screw,” as well as the momentum of a rigid body together with all its derivatives, are also screws, and that a rigid body’s dynamics can be geometrically expressed as a screw equation. The paper relies on a somew...

This paper briefly discusses two of the well-known position/force control schemes used for industrial manipulators: Admittance Control and Hybrid Position/Force Control. In order to eliminate the instability problem that may occur in the customary versions of these schemes for large position errors, a modification is proposed, which is based on determining the joint-space position errors using ...

This paper investigates the problem of adaptive stabilization of nonholonomic mobile robots with nonholonomic constraints under the condition that the kinematic parameters are unknown and no known constants can (lower and upper) bound them. By defining a new unknown parameter which need dynamic updating, and also by using input-state-scaling transformation and backstepping technique, an adaptiv...

The trajectory tracking control problem of dynamic nonholonomic wheeled mobile robots is considered via visual servoing feedback. A kinematic controller is firstly presented for the kinematic model, and then, an adaptive sliding mode controller is designed for the uncertain dynamic model in the presence of parametric uncertainties associated with the camera system. The proposed controller is ro...

A control structure that makes possible the integration of a kinematic controller and a neural network (NN) computed-torque controller for nonholonomic mobile robots is presented. A combined kinematic/torque control law is developed and stability is guaranteed by Lyapunov theory. This control algorithm is applied to the practical point stabilization problem i.e., stabilization to a small neighb...

We present a new set of kinematic equations for front motion in bistable media. The equations extend earlier kinematic approaches by coupling the front curvature with the order parameter associated with a parity breaking front bifurcation. In addition to naturally describing the core region of rotating spiral waves the equations can be be used to study the nucleation of spiral-wave pairs along ...

We present a new open-source software framework (called Humanoid Path Planner – HPP) for path and manipulation planning. Some features like built-in kinematic chains and implementation of non-linear constraints make the framework a good fit for humanoid robot applications. The implementation of kinematic chains takes into account the Lie-group structure (rotation in 3D space SO(3)) of robot con...

We introduce the notion of kinematic controllability for second-order underactuated mechanical systems. For systems satisfying this property, the problem of planning fast collision-free trajectories between zero velocity states can be decoupled into the computationally simpler problems of path planning for a kinematic system followed by timeoptimal time scaling. While this approach is well know...

In this paper an innovative method for robotic manipulator kinematic control and supervision is proposed, both locally, by operator panel, both remote by the use of short-message. A programmable logical controller (PLC) is adopted to obtain a versatile and applicable solution in any robotic system. In particular the problem of end effector positioning in a desired point of the work space of an ...

Learning an inverse kinematic model of a robot is a well studied subject. However, achieving this without information about the geometric characteristics of the robot is less investigated. In this work, a novel control approach is presented based on a recurrent neural network. Without any prior knowledge about the robot, this control strategy learns to control the iCub’s robot arm online by sol...