Naturally-transitioning rate-to-force controller for manipulators

Telerobotic Control Architecture Including Force-Reflection

“…A unique experimental sensor-based real-time telerobotic system including forcereflecting hand controllers (FRHCs) was implemented at NASA Langley Research Center (Williams, Harrison, & Soloway, 1996, 1997Willshire, Harrison, Hogge, Williams, & Soloway, 1992). The control architecture discussed in this report is an extension and adaptation of that system, which includes multiple control modes and shared human and autonomous control.…”

“…The implemented telerobotic control architecture includes not only the usual teleoperation control modes such as pose and rate control but also the novel NaturaUyTransitioning Rate-To-Force Controller (NTRFC). The only previous implementation of the NTRFC was at NASA Langley Research Center (Williams et al, 1996) and it was purely heuristic. The HSF lab will utilize the telerobotic capabilities provided by this research to investigate sensory-rich, human-in-the-loop control and define performance measures for advanced human sensory feedback development.…”

“…It is adapted from a unique hardware system at NASA Langley (Williams et al, 1997). The sensor-rich system is rate based but allows input from various control modes simultaneously: pose, rate, vision, force; others may be added.…”

“…If zero wrench is commanded and the manipulator contacts the environment, the motion will automatically align the manipulator end-effector for minimal Cartesian contact wrench and misalignments. This is called/orce and moment accommodation (FMA) (Williams et al, 1997;Willshireetal., 1992).…”

“…The following subsections present the algorithms for Figure 10. For more detail, see (Williams, 1997). During any control cycle when the operator has moved the FRHC grip fi-om the reference pose, the input command to the manipulator is determined as follows.…”