Methods and systems are described for controlling movement of a continuum robot that includes a plurality of independently controlled segments along the length of the continuum robot. The continuum robot is inserted into a cavity of unknown dimensions or shape. A plurality of forces acting upon the continuum robot by the surrounding cavity are estimated. A positioning command indicating a desired movement of the distal end of the continuum robot is received from a manipulator control. The desired movement is augmented based, at least in part, on the estimated plurality of forces acting on the continuum robot such that movement is restricted to within safe boundaries of the surrounding cavity. The positioning of the continuum robot is then adjusted based on the augmented desired movement.
Compounds of the formulas LAn-Z-X-WwD and BZ-X-WwD wherein: D is a drugmoiety; L is a ligand; B is a blocking group; A is an optional acyl unit; Z is an amino acid or a peptide; X is an aminobenzyl ether self-immolative spacer group; W is an optional second self-immolative group; n is an integer of 0 or 1; and w is an integer of 0 or 1, and compositions of said compounds with pharmaceutically acceptable carrier, diluent and / or excipient, and methods of delivery the drug D via the compounds.