Abstract: A remote center compliance system for compliantly connecting a robot support arm interface to an operator device interface comprises at least three gas-tight spring bellows interconnecting the interfaces and a connection means for connecting the interiors of the bellows in common to an external variable pressure source. The compliance of the system, both rotational and lateral, may be controlled by the applied pressure. The bellows may also be evacuated so that their resultant collapse locks the support structure and operator device together.