Stability analysis for multi-fingered robotic grasping is often formalized as the problem of answering the following questions: can the hand exert contact forces on the object either without a net resultant wrench (thus loading the contacts while creating purely internal forces) or in order to counterbalance an external disturbance (by applying an equal and opposite wrench). However, some of th...

The dimeric ring-shaped sliding clamp of E. coli DNA polymerase III (beta subunit, homolog of eukaryotic PCNA) is loaded onto DNA by the clamp loader gamma complex (homolog of eukaryotic Replication Factor C, RFC). The delta subunit of the gamma complex binds to the beta ring and opens it. The crystal structure of a beta:delta complex shows that delta, which is structurally related to the delta...

Cartesian control algorithms are presented for 6-dof force-reflecting hand-controllers (FRHCs) used for simultaneous operator pose (position and orientation) or rate commands to a telerobotic system and wrench (force/moment) reflection to the operator. The master and slave need not be kinematically-similar because the information is transferred in Cartesian space. The task wrench dominates whil...

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The optical torque wrench is a laser trapping technique that expands the capability of standard optical tweezers to torque manipulation and measurement, using the laser linear polarization to orient tailored microscopic birefringent particles. The ability to measure torque of the order of kBT (∼4 pN nm) is especially important in the study of biophysical systems at the molecular and cellular le...

This paper presents an approach for stiffness modelling of the lower mobility parallel manipulators using the generalized Jacobian. The approach can be implemented by two steps:(1) The first order deflection analysis by decomposing twist space of the end-effector into a pair of complementary twist subspaces associated with the permitted and restricted instantaneous motions, (2) The kinestatic a...

In this paper a unified contact force control approach for cable-driven parallel robots (CDPR) is proposed. The contact force controller is governed by two control loops: 1) An inner impedance control loop enforcing a dynamical relationship between the internal forces and the end-effector velocities to maintain a desired tension level in the cable system. 2) An outer admittance control loop con...