Of gravity and the terms puma shoes of the inertia dyadic.Thewrist,link where I I = M-wg2 ** r12three and link two of a PUMA 560 arm were detached in order Mgto measure these parameters. The mass of each component was r is theinertiaabouthe axis of rotation;determined with a beam balance; the cenotfergravity was located is the weight of the link;by balancing each link on a knife edge, once orthogonal to each w is thdeistance fromeacshuspensionaxis;

So the total Measurement of the Motor and Drive Inertiamotor and drive contribution ateach joint was determined by anidentification method. This contribution is considered separately A parameter identificationmethod was used t o puma trainers learnthefrom the I,, term of the link itself because the motor and drive totalrotationalinertiaateachjoint.Thisinertiaincludes t,heinertia seen through the reduction gear does not contribute to the effective motor and drive inertia and the contribution due .

By puma suede subtract-data presented below include armature inertia andgear ratios, so ing the arm contributions, determinedfrom direct measurements,these forces can be determined. from the measured total inertia, the motor and drive inertial con- The parametersof the wrist linkswere not directly measured. tributions were found.The wrist itself was not disassembled. But the needed parameterswere estimatedusingmeasurements of the wristmass and the Measurement Toleranceexternal dimensions of the individual links.

To obtain the inertialterms, the puma sliders wrist links were modeled as thin shells. A tolerance for each direct measurement was established as the measurement was taken.ThetolerancevaluesarederivedMeasurement of Rotational Inertia from the precision or smallestgraduation of the measuring in- strument used, or from the repeatability of the measurement it- The two wire suspension shown in Figure1 was used to mea- self. Thetolerancesarereportedwhere the data are presented.

Of the link, thelocation of the center of gravity, the distancefromthe wire attachment points to the axis of rotation, the length of Table 4. Link Masses (kilograms; kO.01 1%)the wires, andtheperiod of rotationaloscillation. Theinertiaabout eachaxis is measured by configuring the link to swing Link Massabout that axis. Rotational oscillation puma uk is started by twisting andreleasing the link. If one is carefulwhenreleasing the link, it Link 2 17.

40is possible to start fundamentalmodeoscillationwithout visi- Link 3 4.80blyexcitingany of the other modes. The relationshipbetween Link 4* 0.82measured properties and rotational inertia is: Link 5* 0.34 Link 6* 0.09 * This method was suggested by Prof. David Powell. Link 3 wiCthomplete LVrist 6.04 Detached Wrist 2.24 * Values derived from external dimensions; f 2 5 % . The positions of the centers of gravity are reported in Table 5. The dimensions rz! ry and rz refer to the x, y and z coordinates 513