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Robotics and Automation Lab Hybrid actuator with air muscles and spherical MR-brake

Hybrid actuator with air muscles and spherical MR-brake

HybridActuatorSphericalThis research was motivated by the possibility of haptic rendering of rigid and elastic virtual objects with a compact and powerful actuator.  A 2-DOF compact, high-torque haptic device has been developed.  The system uses a spherical MR-brake and a unique air muscle configuration that utilizes three air muscles to control two degrees of freedom.  To the best of our knowledge, this is the only haptic device using air muscles and a spherical brake.

The device has peak torque output of about 8.1 Nm (4.4 Nm active torque output and 3.7 Nm passive torque output) and has a 76.2 mm diameter at the base and 152 mm height.  It can apply 16 N force at the tip of the joystick handle which can be complemented by an additional 13.5 N when the air muscles saturate and the MR-brake is locked.



  • “Haptic joystick with hybrid actuator using air muscles and spherical MR-brake,” Mechatronics, vol. 21, pp. 952-960, 2011.
  • “Position Control of Multi-DOF Hybrid Actuator with Air Muscles and MR-brake,” Proceedings of the ASME 2013 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference IDETC/CIE 2013, Portland, OR, August 2013.