Thesmallbendradiusonthecapstanandthehighforcesinvolvedmadehightensilestrength,small diameterandresistancetofrayingthecriticalpropertiesforcablelongevity.Avarietyofcablematerials weretriedduringdevelopment includingstainlesssteel,DacronTM,KevlarTM,andVectran TM. A0.69mm (0.027in)diameter braided Spectra TMcablewassettledonasthebestchoiceforstiffness anddurability. Thehousing wasmadeof6061-T6 aluminum. Overall dimensions oftheactuator package were7.7cm (3.04in)wideby6.5cm(2.56in)longby2cm(0.77in)tall.A0.64-cm (0.25in)thickaluminum interface plateattached theactuator totheglove,increasing overallheightto2.64cm(1.02in). Themotorwasselected toproduce thenominal maximum of31N(7Ibf)cabletension (assuming a mechanical efficiency of70%)atacurrent of1.35A,andsimultaneously support cablevelocities upto 58cm/s(23in/s)witha+30VDCpowersupply. Theencoder, withtwochannels inquadrature at256 counts/revolution, wouldgive1300countsoverthenominal cabletravelof2.5cm(1in). Development Whiletheactuator wasinfabrication, itbecame evident thatthefirstnewglovewouldhavesignificantly higherresistance forcesthanoriginally expected. Themaximum cabletension required increased to roughly 70N(16Ibf).Ratherthanredesign theactuator, itwasdecided torelaxthe30Vmaximum voltage requirement; apossibility sincetheMkIunitwouldnotbeusedinNBS.Witha+42.5VDCpower supply, thesamemotorcouldproduce 70N(16Ibf)cabletension atamaximum velocity of64cm/s(25 in/s)withacurrent of2.7A,slightlyaboveitsnominal rating.Nootherchanges wererequired. Anelement whichcouldnotbecompleted untilthenewglovearrived wasthemapping between torque andstateoftheMCPjoint.Afterdelivery, theglovewasintegrated withtheactuator onabenchtop setup whichclamped thewristringinplaceandpressurized thegloveto30kPa(4.3psi)overambient. With thisapparatus itwasnotpossible toperform testswithanoperator's handinsidetheglove,butthe unoccupied glove's properties couldbemeasured. For"occupied" tests,agloveboxwasusedtoprovide thecorrectpressure differential, butphysical accesstotheactuator wasprecluded inthatsituation. Sincetheactuator itselfincludes aposition sensorandameansofapplying knowntorque, theglove's torque/state mapcouldbegenerated without anyextraequipment. Analgorithm wasdeveloped byDr. RobertSanner (University ofMaryland, College Park)toperform thisautomatic calibration procedure. Detailsofthisalgorithm havebeenpresented in[7].Essentially, theactuator firstdrivestheglovetoa hardstoptocalibrate theincremental encoder, thenrelaxes tozerotorque. Thenitstepsthetorqueupin finiteincrements toitsmaximum value,thenbackdowntozero,recording theMCPpositions ateach step.Itisexpected thatasimilarprocedure wouldberunoperationally everytimetheglovesystems werepowered uptoensureacurrent calibration. Ittakesabout90seconds andcanbeperformed with theoperator's handinside(relaxed). System measurements madeinthiswaylumptogether the properties ofthegloveandactuator, e.g.friction, damping andinertia. Foroperational purposes thisis sufficient, sincethesystem functions asaunit. Results Initialtestsshowed thattheforcesresisting MCPmotionwere,indescending orderofmagnitude: stiffness (position-dependent), frictionandstiction, viscous (velocity-dependent), andinertial; asexpected fromILC'sprevious gloveinvestigations. Thedataobtained withtheactuator system correlated wellwith ILCDoverdatatakenonthesamegloveusinganInstronmachine attheirfacility. Theobserved levelofstaticfrictionandstiction (somefromtheglove;somefromtheactuator) ledtothe addition ofdither(asmall-amplitude high-frequency ripple)tothetorquecommands. Thisreduced the effective magnitude offrictionforcesbyroughly 4.5N(1Ibf).Theposition- andvelocity-dependent forces weremapped andcompensated bythecontrolsystem, and(aspreviously described) theinertialforces wereleftuncompensated. Intheory,theoperator wouldfeeltheaddedinertiaoftheglove(andactuator) butnoneoftheotherforces. 93