Novanta MAG 2025-2026 - Flipbook - Page 34
Innovation and progress never stops. IT’S INMOTION
INTEGRATED
ROBOT JOINT
DESIGN
CONSIDERATIONS
At Novanta, our engineers bring deep expertise in
motion control and system design - helping innovators
navigate these challenges with solutions.
INTRODUCTION
Robots are transforming industries, from
factory lines to surgical suites. At the heart
of every robotic arm lies its joint design – a
compact integration of motors, encoders,
bearings, brakes, drives, and gearboxes. How
these components are selected and combined
determines not only performance, but also
reliability, safety, and ef昀椀ciency. This feature
explores the critical design elements that
make robot joints both powerful and precise.
MOTOR SELECTION
Every joint begins with a motor. Most
designs use brushless DC (BLDC) frameless
motors to minimize size and weight while
maximizing torque. Torque density – torque
output relative to volume – is crucial,
especially in joints further down the arm,
where weight impacts agility. Wider, 昀氀atter
motors often provide higher torque and
allow through-holes for cable routing and
additional components.
Smoothness also matters. Cogging torque in
slotted motors can cause ripple at low speeds.
Novanta’s Omni+ motors reduce cogging to
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just 1-1.5% of rated torque, while Agility motors
eliminate it entirely with slotless technology.
Selecting the right motor requires balancing
torque, speed, and thermal limits. Ef昀椀ciency,
measured by the motor constant (Km), and
thermal resistance (Rth) must be considered
to prevent overheating. Novanta offers
multiple winding options to match diverse
application needs.
DRIVE SELECTION
Traditionally, drives were too bulky to 昀椀t inside
joints. Today, innovations in power density
have enabled Novanta’s Summit Series drives
– Denali, Capitan, Everest S – to be integrated
directly into joints. Designers must evaluate
current ratings, ef昀椀ciency, and thermal
performance. Drives with high output power
but poor ef昀椀ciency may require heat sinks
that defeat compactness. Optimized motordrive pairings, like Omni+ with Summit,
reduce development risks. Safety is also
central: features such as over-current and
over-temperature protections and certi昀椀ed
functions such as Safe Torque Off (STO)
safeguard both the robot and its environment.
