Peter B. Goldsmith

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The goal of iterative learning control (ILC) is to improve the accuracy of a system that repeatedly follows a reference trajectory. This paper proves that for each causal linear time-invariant ILC, there is an equivalent feedback that achieves the ultimate ILC error with no iterations. Remarkably, this equivalent feedback depends only on the ILC operators(More)
We consider the control of Port-Controlled Hamiltonian (PCH) systems, which are a generalization of Euler-Lagrange Systems. A new matching equation for PCH systems is developed so that Interconnection Damping Assignment Passivity-Based Control (IDA-PBC) can be extended to the regulation of some underactuated PCH systems whose kinetic energy must be(More)
This paper investigates the kinematics and stiffness of an isotropic three-legged manipulator having six degrees of freedom. Rotary motors at the base rotate the tool by using the extensible legs as drive shafts. The manipulator has the positional stiffness of a parallel manipulator and the rotational stiffness of a serial manipulator. Low inertia results(More)
Hybrid position/force control enables a robot to apply specified forces to a constraint while moving along a prescribed path. Flexibility of the motor transmissions (joint flexibility) is a major concern in the design of hybrid controls, particularly with regard to system stability. While much work on hybrid control has been toward the development of(More)
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