A Space Free-Flying Robot (SFFR) includes an actuated base equipped with one or more manipulators to perform on-orbit missions. Distinct from fixed-based manipulators, the spacecraft (base) of a SFFR responds to dynamic reaction forces due to manipulator motions. In order to control such a system, it is essential to consider the dynamic coupling between the manipulators and the base. Explicit d...

Robotic manipulators are widely used to help in dangerous, monotonous, and tedious jobs. Most of the existing robotic manipulators are designed and built in a manner to maximize stiffness in an attempt to minimize the vibration of the end-effectors. This high stiffness is achieved by using heavy material and bulky design. Hence, the existing heavy rigid manipulators are shown to be inefficient ...

We have developed a planner for redundant manipulators that is fast, eeective and versatile, based on the idea of treating each link of a rigid-linked robot as if it were slightly exible and under the innuenceof a potentialeld. We justify the method by exploringsome simple examples, and brieey describe the extensions to the basic method that allow it to plan paths for manipulators with revolute...

An approach to force and visual control of robot manipulators in contact with a partially known environment is proposed in this paper. The environment is modelled as a rigid object of known geometry but of unknown and time-varying position and orientation. An algorithm for online estimation of the object pose is adopted, based on visual data provided by a camera as well as on forces measured du...

This paper addresses the problems of planning and control of the on-orbit maneuvering of large and highly flexible structures by free-flying robots. An approach is proposed where the robots use their thrusters to control the “rigid body” motion of the robot-structure system being transported and their manipulators to control and damp out vibration in the structure induced by the thruster firing...

We propose a new model for robot manipulators with rigid links and flexible joints. Our model is expressed in Cartesian dependent coordinates which represent the positions, orientations and velocities of the links and the rotors, as opposed to independent generalized coordinates in which classical “Lagrangian” models are defined. The model consists of a set of dynamics equations and holonomic c...

This paper describes a method to solve the direct kinematics of a generic Stewart-Gough manipulators. The method is formulated in terms of a search in the space of rigid body transformations. The underlying idea is that the solutions of the direct kinematics can be obtained by moving the end-effector body according rotations and translations and accounting for the rigidity conditions. The paper...

By using the integrator backstepping technique, the control of rigid link, electrically driven robot manipulators is addressed in the presence of arbitrary uncertain manipulator inertia parameters and actuator parameters. The control scheme developed is computationally simple owing to the avoidance of the derivative computation of the regressor matrix. Semiglobal asymptotic stability of the con...

In this paper we present an adaptive appoach to observe the joint velocity for rigid robot manipulators. This approach is based on the neural network and sliding mode technique. The adopted neural network is of the MLP (Multi Layer Perceptron) type with one hidden layer. The functions of the dynamic model of the robot manipulator are assumed unknown. The neural network parameters are adapted on...