A robotic arm for a minimally invasive surgical system includes a parallel spherical five-bar linkage adapted to spherically rotationally move a robotic surgical tool coupled to the parallel five-bar spherical linkage about a remote center of spherical rotation. The five-bar spherical linkage is posed in only a range of compact poses. A constraint limits the parallel five-bar spherical linkage to only the range of compact poses.

A robotic surgical tool includes an elongate shaft having a working end and a shaft axis, and a pair of linking arms each having a proximal end and a distal end. The proximal end is pivotally mounted on the working end of the shaft to rotate around a first pitch axis to produce rotation in first pitch. A wrist member has a proximal portion pivotally connected to the distal end of the linking arm to rotate around a second pitch axis to produce rotation in second pitch. An end effector is pivotally mounted on a distal portion of the wrist member to rotate around a wrist axis of the wrist member to produce rotation in distal roll. The wrist axis extends between the proximal portion and the distal portion of the wrist member. The elongate shaft is rotatable around the shaft axis to produce rotation in proximal roll. At about 90 pitch, the wrist axis is generally perpendicular to the shaft axis. The proximal roll around the shaft axis and the distal roll around the wrist axis do not overlap. The use of the linking arms allows the end effector to be bent back beyond 90 pitch. The ability to operate the end effector at about 90 pitch and to bend back the end effector renders the wrist mechanism more versatile and adaptable to accessing hard to reach locations, particularly with small entry points such as those involving spinal, neural, or rectal surgical sites.

A robotic surgical tool includes an elongate shaft having a working end and a shaft axis, and a pair of linking arms each having a proximal end and a distal end. The proximal end is pivotally mounted on the working end of the shaft to rotate around a first pitch axis to produce rotation in first pitch. A wrist member has a proximal portion pivotally connected to the distal end of the linking arm to rotate around a second pitch axis to produce rotation in second pitch. An end effector is pivotally mounted on a distal portion of the wrist member to rotate around a wrist axis of the wrist member to produce rotation in distal roll. The wrist axis extends between the proximal portion and the distal portion of the wrist member. The elongate shaft is rotatable around the shaft axis to produce rotation in proximal roll. At about 90 pitch, the wrist axis is generally perpendicular to the shaft axis. The proximal roll around the shaft axis and the distal roll around the wrist axis do not overlap. The use of the linking arms allows the end effector to be bent back beyond 90 pitch. The ability to operate the end effector at about 90 pitch and to bend back the end effector renders the wrist mechanism more versatile and adaptable to accessing hard to reach locations, particularly with small entry points such as those involving spinal, neural, or rectal surgical sites.

A nanopositioning system for producing a coupling interaction between a first nanoparticle and a second nanoparticle. A first MEMS positioning assembly includes an electrostatic comb drive actuator configured to selectively displace a first nanoparticle in a first dimension and an electrode configured to selectively displace the first nanoparticle in a second dimensions. Accordingly, the first nanoparticle may be selectively positioned in two dimensions to modulate the distance between the first nanoparticle and a second nanoparticle that may be coupled to a second MEMS positioning assembly. Modulating the distance between the first and second nanoparticles obtains a coupling interaction between the nanoparticles that alters at least one material property of the nanoparticles applicable to a variety of sensing and control applications.