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This paper presents a unified approach for inverse and direct dynamics of constrained multibody systems that can serve as a basis for analysis, simulation, and control. The main advantage of the dynamics formulation is that it does not require the constraint equations to be linearly independent. Thus, a simulation may proceed even in the presence of(More)
Most studies on adaptive coordination of multi-robot systems assume exact knowledge of system kinematics and deal only with dynamic uncertainties. However, many industrial applications involve tasks in which a multi-robot system interacts with geometrically unknown environments. In this paper, we consider a multi-robot system grasping a rigid object in(More)
This paper is focused on an adaptive vision system for the guidance of a robot to intercept a non-cooperative target satellite with unknown dynamics parameters. A Kalman filter is developed to reliably estimate the states of the object as well as all of its inertial parameters - namely, the moment-of-inertia ratios, the center-of-mass location, and the(More)
This paper describes the design and development of a mechatronic testbed facility which allows high-fidelity and low-cost testing of the joint prototypes of a manipulator in a highly flexible environment. The testbed system consists of a set of load motors whose shafts are connected to those of the joint prototypes through a set of torque transducers. A(More)
The application of joint-torque sensory feedback (JTF) in robot control has been proposed in the past that, unlike the model-based controllers, does not require the dynamic model of the robot links. JTF, however, assumes precise measurement of joint torque and accurate friction model of the joints. This paper presents an adaptive JTF control algorithm that(More)
This paper addresses the dynamics and control of direct drive robots with positive joint torque feedback. We analytically derive the system dynamics in closed form. Even though it is coupled and nonlinear in general , it is substantially simpler than the robot link dynamics. We also derive conditions on the robot conng-uration which result in linear(More)
  • Farhad Aghili
  • 2009
Robotic capture of a tumbling target-satellite means that the space robot's hand and the target grapple point arrive at a rendezvous point with the same velocity and then the chase vehicle mechanically connects into the target using a grapple device. This paper is focused on optimal control of the space manipulator in the postcapture phase so as to bring(More)
—A new torque control strategy for brushless motors is presented, which results in minimum torque ripple and copper losses. The motor model assumes linear magnetics, but contains a current limit which can delimit the onset of magnetic saturation , or be the motor amplifier current limit, whichever is reached first. The control problem is formulated and(More)
This paper focuses on the guidance of a robot manipulator to capture a tumbling satellite and then bring it to state of rest (detumbling). First, a coordination control for combined system of the space robot and the target satellite, which acts as the manipulator payload, is presented so that the robot tracks the optimal path while regulating the attitude(More)