Abstract: A robot assembly system which uses a set of related databases to separately describe (1) what task is to be performed by the system, (2) details about how to perform the task (e.g., specifying the strategy routine to be used to insert a part into an assembly), and (3) data describing the workcell and object locations. The system includes software routines which control how each robotic operation is performed, but those aspects of each robotic operation which vary from part to part or from operation to operation are determined by the data in the databases. By keeping the what, how and where aspects of each assembly task separate, the present invention makes it possible to change them independently. Furthermore, the task to be performed by the system is typically defined by a Sequence database, which enables new tasks to be defined by simple, task level programming instructions, such as TRANSFER PART sn7400 TO u20.

Abstract: An end effector comprises a force sensor cooperating with an output flange at the wrist of a robot arm. The force sensor includes a cylinder mounted in the robot arm having a piston whose outer end is attached to the output flange of the arm at its outer end; its inner end comprising one side of a pressure chamber pressurized to a known level. The piston is mounted on bushings for sliding linear movement within the sleeve of the piston along the axis of vertical movement of the arm, but levers or other mechanisms may be used to provide the required motion. The pressure in the chamber is calibrated to a known level of a pressure which is to be applied to the part being worked by the end effector. The piston carries a position encoder; when the pressure within the pressure chamber is exceeded, movement of the position encoder is detected and signaled to a position controlling computer.