Actuators and Mechanics
BLDC vs Stepper Motors in Robot Joints
Steppers win on cost and simplicity for holding tasks at low speed: they produce full torque at zero speed with no feedback and no tuning....
Section 08
Actuators and Mechanics
Gearboxes, motors, grippers and the cable that fails before any of them.
Actuators and Mechanics
Direct Drive vs Geared Joints: The Real Trade
A gearbox multiplies torque by its ratio and divides everything good by roughly the same amount: backdrivability, bandwidth and...
Actuators and Mechanics
Harmonic vs Cycloidal Drives: Backlash, Life, Price
Harmonic drives go in wrists and light arms: near-zero backlash under one arcminute, ratios from 30:1 to 320:1 in one stage, and low mass....
Actuators and Mechanics
Aluminium, Steel, Carbon: What Robot Arms Are Made Of
Cast aluminium dominates because it wins on specific stiffness, the ratio of stiffness to density, at a cost castings can deliver in...
Actuators and Mechanics
Brakes and Backdrivability: What Happens on Power Loss
On power loss, a high-ratio geared arm typically holds by friction alone and is then locked by fail-safe brakes; a backdrivable low-ratio...
Actuators and Mechanics
Dress Packs: The Number One Cause of Robot Downtime
Robot mechanics routinely reach 60,000 to 100,000 operating hours. The cable package on the outside frequently fails in 2 to 5 million...
Actuators and Mechanics
Vacuum, Two-Finger, Magnetic: Gripper Types Compared
Match the gripper to the surface, not the part. Vacuum needs a smooth sealed area of a few square centimetres, magnets need ferrous...
Actuators and Mechanics
Torque Density: The Number That Limits Every Robot Arm
Torque density is torque divided by the mass producing it, and it governs everything downstream: payload, reach, acceleration and, on a...
Actuators and Mechanics
Robot Maintenance Intervals: Grease, Belts, Batteries
Three items cause most unplanned robot stops: cables, batteries and grease. All three are scheduled maintenance items with known intervals,...
Actuators and Mechanics
Series Elastic Actuators: Compliance Built Into the Joint
A series elastic actuator puts a deliberate spring between the gearbox output and the load. Measuring the spring's deflection gives an...