Robotics
Direct drive
ActivePublished
Key
innovation
No gearbox: full reversibility and force sensing at the cost of requiring a large motor torque.
Category
Robotics
Abstraction level
Building block
Operation level
Robot control
How it works
Motor torque goes straight to the joint at 1:1. It is controlled via current/field, and the lack of a gearbox means the current-torque relationship is simple and repeatable, easing torque and impedance control. This, however, requires high-torque-density motors and adequate cooling.
Problem solved
Reduction gearboxes introduce backlash, friction and compliance and degrade backdrivability and force sensing, limiting dynamic, compliant interaction with the environment.