Abacus Drive: a novel, highly efficient rotary transmission | SRI International

Toggle Menu

Abacus Drive: a novel, highly efficient rotary transmission

SRI gives rotary transmissions a makeover with a new cycloidal rolling motion that results in very high efficiency at a reasonable cost.

SRI International and Harmonic Drive Systems are jointly developing Abacus Drive, a rotary mechanical transmission that uses a novel pure rolling cycloid motion to achieve very high efficiency while maintaining high precision and at a reasonable cost.

Abacus Drive utilizes variable effective diameter rollers, where roller bearings move in and out of a groove of variable width, causing the bearings to change their diameter depending on where they are in the groove, which results in a pure rolling motion.

Abacus Drive has very low backlash, the movement of output when the motor is fixed – critical for high-precision applications such as robotics. Other features of Abacus Drive include low back-driving torque and significant cost-savings over alternatives.

SRI has licensed the Abacus Drive design to Harmonic Drive Systems, and the two companies are collaborating to commercialize the technology.