CLOSED-FORM SOLUTION OF THE DIRECT KINEMATICS OF THE 6-3 TYPE STEWARTPLATFORM USING ONE EXTRA SENSOR

A procedure for the determination of the actual configuration of the 6 -3 type Stewart Platform is presented. The procedure makes use of one extra sensor in addition to the six that provide the mechanism leg len gths. The use of one extra sensor suitably located on the mechanism al lows the direct position analysis to be solved in closed form and make s it possible to obtain a one-to-one correspondence between the sensor measurements and the configuration of the mechanism in almost the ent ire workspace. Particular configurations where the correspondence is n ot one-to-one are outlined and criteria to identify them given. Sensit ivity to sensor measurement errors is investigated.