Precision X-Y robotic object handling using a dual GMR bridge sensor

A dual integrated GMR bridge sensor, which is able to simultaneously detect x and y components of an external magnetic field, was demonstrated, and ap plied to the precision robotic placement of objects. Two orthogonal GMR bri dges are used, biased by two sets of integrated Co-78 Pt-22 film permanent magnets with different coercivities (1230 Oe and 522 Oe, respectively). The field sensitivity is 0.35 mV/(V x Oe) in each field direction. For the pos itioning application, an absolute accuracy of 10 mum in x-direction has bee n achieved over more than 1900 cycles which is insensitive to sensor offset s and thermal drifts.