Novanta MAG 2025-2026 - Flipbook - Page 37
P. 36
INMOTION #3
At Novanta, our engineers bring deep expertise in
motion control and joint design – helping innovators
navigate these challenges with solutions.
FEEDBACK SELECTION
Precision relies on feedback. Hall effect
sensors may suf昀椀ce for commutation, but
high-accuracy applications require encoders.
Incremental encoders provide relative position
but need homing routines, while absolute
encoders deliver exact positioning at startup.
For maximum precision, some systems use
dual encoders – one on the motor shaft,
another on the joint output – to compensate
for backlash and 昀氀exure. Resolution, accuracy,
and repeatability are all critical metrics.
Novanta offers optical encoders for extreme
precision and inductive encoders where
ruggedness and resistance to contamination
are required.
GEARBOX OPTIONS
While direct-drive designs offer zero backlash
and maximum precision, most joints rely
on gearboxes to achieve higher torque at
lower speeds. Options include strain wave
gearboxes (compact, zero backlash, but less
stiff), cycloidal gearboxes (ef昀椀cient, stiff, but
heavier), and planetary gearboxes (affordable,
lower ratios, some backlash). Lubrication
is often overlooked but critical, as grease
breakdown can affect performance and
impose design constraints on seals
and housings.
BEARING SELECTION
Bearings de昀椀ne joint durability. Choices
depend on expected speeds, loads, and
integration with gear systems. Crossed roller
or four-point contact bearings often support
strain wave gear outputs, while high-speed
input shafts require precise, heat-tolerant
bearings. Shielded bearings minimize
friction, while sealed bearings offer better
contamination protection - crucial when
sensitive encoders are nearby.
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BRAKE SELECTION
Some joints require brakes to hold loads
safely. Power-off brakes are favored for safety,
preventing drops during outages. Designers can
choose between spring-activated brakes
(cost-effective but less precise) and permanent
magnet brakes (compact, zero-backlash). For
static applications, even simple solenoid pin
locks can be effective. The key is to size brakes
to slightly exceed motor torque output.
HOUSING CONSIDERATIONS
Bringing all components together demands
careful housing design. Engineers must balance
manufacturability, maintenance access, thermal
management, and wire routing. Housing
geometry should manage heat from motors,
drives, and brakes, while shielding wires
against electromagnetic interference. Compact
integration requires meticulous tolerance
analysis to ensure alignment and long-term
performance.
Novanta offers optical encoders for
the highest levels of precision, and
inductive encoders for applications
demanding ruggedness and
resistance to contamination.
CONCLUSION
Designing a robot joint is an exercise
in precision engineering – balancing
torque, thermal performance, safety, and
compactness. Novanta’s motors, drives,
encoders, and systems expertise empower
engineers to meet these challenges head-on,
delivering robot joints that set the standard
for speed, accuracy, and reliability. For
manufacturers and innovators, the future of
robotics is being built joint by joint.
