A new scheme for on-line fault detection and control of assembly operation via sensory information

Based on requirements imposed by flexible assembly of electromechanical devices with robot arms the operation of an external sensor system is discussed allowing both quasi-continuous trajectory control and discrete sequence control during manipulation. The paper concentrates on a method for programming the sensor modules individually with expected sensor values for each of a number of predefined assembly phases. The sensor modules compare actual and expected values to provide discrete status information so that programming errors are detected in the program verification phase and faulty states of the working environment when assembly is in progress. In order to facilitate system configuration and programming, a modular approach is taken by implementing sensor-modules on a distributed microcontroller network within the assembly cell.