298 Index
shear pin torque limiters, 125f
silent (timing) chain, 82–83f
single-axis air-bearing stages, 7f, 13f
sinusoidal commutation, 34–35
skid steering (differential), 141, 150–152, 167, 193–195,
194f
slider cranks, 243–245, 244, 244f
slide switches, 268f, 269
snake mobility systems, 226
software, for motion controllers, 15
Sojourner, 155
solenoids
about, 60–63, 61f
box-frame, 63
C-frame, 63
open-frame, 63
rotary, 64–66, 65f
tubular, 64
solid free-form (SFF) fabrication, xxx
Solid-Ground Curing (SGC), xvi, xviii–xx, xix(f)
Soligen Technologies, xxvi, xxvii
speed control, 10
spherical arm geometry, 248f–249f
spiral bevel gears, 89
spring suspension systems, 130–131
spur gears, 89
stability
minimum requirements for static, 135, 136f, 192
and walker mobility systems, 201–202, 210f
stair climbing
and center of gravity, 132
tracked mobility systems and, 165
Stanford University, xxxii
static stability minimums, 135, 136f, 192
steel-core linear motors, 32–33f
steering
Ackerman steering layout, xii, 152, 179f, 190
all-terrain cycles (ATCs), 197
articulated steering, 167
drive/steer modules, 195f–197f
history, 189f–190
skid steering (differential), 141, 150–152, 167, 193–195,
194f
syncro-drives, 196–197f
three-wheeled layouts, 137–139f, 138f, 190, 191f, 195f
tracked mobility systems, 167–168
two-tracked drivetrains, 192–193f
two-wheeled layouts, 190, 191f
in walker mobility systems, 211f
step errors, 9
stepper motors, 16, 18t, 37–40, 71
(stepper motors cont.)
hybrid stepper motors, 38–40f, 39f
permanent-magnet (PM) stepper motors, 38
variable reluctance (VR) stepper motors, 38
stepping motors, 16, 18t
stereolithography (SL), xv, xvi, xvii(f)–xviii
STL (Solid Transfer Language) files, xvi
straight bevel gears, 89
Stratasys, xxiv
synchronous drives, 75
T
tachometers, 5, 20
permanent magnet (PM), 52–53
shunt wound, 52
tail dragger, 136f, 137
terrain
center of gravity and, 132, 164
crevasses, 163–164
tracked vehicles and, 163–164
Three-Dimensional Printing Laboratory, xxvi
3D Printing (3DP), xvi, xxv(f)–xxvi
3D Systems, xviii, xxviii
timing belts, 75f–76f
torque control, 10
torque-control loop, 7
torque/force, of solenoids, 62
torque limiters, 121–125f, 122f, 123f, 124f
Torsen differential, 140
tracked crawlers, 224f
tracked mobility systems
center of gravity (cg) shifting, 164
components, 164
crevasse negotiation, 163–164, 166
drive sprockets, 174
four-track drivetrains, 181–184, 182f, 183f
and ground pressure, 163, 165
ground support methods (suspension), 174–178
fixed road wheels, 175f
guide blades, 175
road wheels mounted on sprung axles, 176–178f,
177f
rocker road wheel pairs, 176f
half-track layout, 180f
ideal terrain for, 163–164, 166
obstacle negotiation height, 174
one-track drivetrains, 178–179f
pinch volume, 168–169
six-track drivetrains, 184–185f
size range of, 165–166
stair climbing, 165