Among the challenges to advanced robotics and other mechatronic applications is the ability to get a range of precision motion with few parts in a compact volume.
The German Aerospace Research Centre (DLR) believes it has met this challenge with innovative electromechanical actuators designed around patented planetary roller screw drives (PRSDs).
Originally created to serve as an artificial muscle in a robotic hand, the PRSD is believed to combine the principles of the planetary gear and roller bearing to create a new type of linear translator that transforms fast rotary motion into powerful, low- speed linear movement.
The translator features an outer cage, a spindle rod, and a planetary set of grooved rollers sandwiched in between. The combination of the cage and planetary roller set, linked by retainer rings, acts as a nut engaging the screw with markedly reduced friction.
When PRSDs are blended with brushless DC motors, the result is a compact, simple alternative to hydraulic and pneumatic actuators for applications ranging from intricate, small-range motion tasks to automotive systems to heavy lifting gear.
The integration of position and force sensors into the PRSD translators is, according to a statement, leading to a new generation of mechatronic devices with programmable impedance and dynamic behaviour.