Why Acceleration, Not Just Top Speed, Drives Torque Requirements
Sizing drive motors for a mobile robot based purely on target top speed misses a major factor: reaching that speed within a given acceleration time requires additional torque beyond what's needed to simply maintain speed once achieved. A robot that only needs to cruise at a modest speed but must reach it very quickly can require substantially more motor torque than a robot targeting the identical top speed with a more relaxed acceleration allowance — torque and acceleration time are directly linked, not independent specifications.
Incline angle compounds this further: climbing a slope adds a gravity-component torque requirement on top of whatever's needed for level-ground acceleration, and this added requirement scales with the sine of the incline angle — a seemingly modest incline can meaningfully increase peak torque demand beyond what a flat-ground calculation alone would predict, which is exactly why a drive system validated only on flat terrain can be undersized for its actual real-world operating environment.
Wheel diameter and motor count both directly affect the required torque-per-motor for a given overall performance target — larger wheels reduce required torque per unit of linear force (at the cost of needing higher RPM for the same linear speed), and splitting drive force across more motors reduces the torque demand on each individual motor, which is why these aren't independent variables but a genuinely coupled system that needs solving together, not motor torque estimated in isolation.