Robotic arm with five-bar spherical linkage

A robotic arm for a minimally invasive surgical system, the robotic arm comprising:

• a parallel five-bar spherical linkage that includes
• a ground link having a first end and an opposing second end;
• a first pair of links pivotally coupled at a first intermediate joint and coupled at a first end of the first pair of links to the first end of the ground link;
• and
• a second pair of links pivotally coupled at a second intermediate joint, coupled at a first end of the second pair of links to the second end of the ground link, and coupled at a second end of the second pair of links to a second end of the first pair of links to form an outboard joint;
• the parallel five-bar spherical linkage to spherically rotationally move a robotic surgical tool coupled to the parallel five-bar spherical linkage about a remote center of spherical rotation;
• and
• a constraint coupled to the robotic arm, the constraint to limit the parallel five-bar spherical linkage to only a range of compact poses in which the first intermediate joint is constrained to only a predetermined side of a first plane that includes the remote center, the outboard joint, and the first end of the ground link, and the second intermediate joint is constrained to only the predetermined side of a second plane that includes the remote center, the outboard joint, and the second end of the ground link.