Duty cycle
The fraction of an actuator's total operating time spent in a particular state, such as actively moving versus holding a fixed position, or powered on versus idle. A joint's duty cycle, specifically the fraction of time spent holding position against gravity or inertia, is a key input to Section 3G's Check 2 and to sizing any gravity-compensation solution correctly.
Defined in 2 GAGE programs, which carry 11 distinct definitions of it. The wording above is taught in Engineering Judgment and Professional Formation.
How each discipline defines it
The same term does different work depending on who is using it. These are the definitions as each program teaches them, unedited.
The pattern and proportion of time a mechanism spends in each of its operating states, most relevantly for this topic the split between static holding time and active motion time, which determines whether static holding torque (favoring gravity compensation) or cyclic motion energy (favoring energy storage) is the dominant engineering concern for a given mechanism. As a rough starting guide, a joint dwelling in a static position for more than half its cycle time is usually worth analyzing for gravity compensation first; a joint with a fast, frequent absorb-then-release pattern is usually worth analyzing for energy storage first, per the five-question flow in Section 3F.
The fraction of time during one motion cycle that the actuator is under load. A 100 percent duty cycle means continuous full-load operation; a 30 percent duty cycle means the actuator operates at load for 30 percent of the cycle and is unloaded or stopped for the rest.
The percentage of one PWM period during which the signal is at logic-high. A 0% duty cycle is always low; 100% is always high; 50% is high for half the period. For a motor drive, effective voltage delivered is approximately D x VCC.
The percentage of one PWM period during which the output is active (high). A 50% duty cycle delivers half the peak voltage as average voltage to the motor.
The fraction of time an actuator can be operated at rated conditions without exceeding thermal limits, typically expressed as a percentage. A 25% duty cycle means the actuator can run at rated load for one second out of every four.
Terms it appears with
Not an alphabetical neighbourhood: these are the terms taught in the same lessons, ranked by how often they appear together.