Unmet Need
Mechanical motion has been in constant development since the development of the pulley. New technology such as computer-controlled motion has emerged in the 20th and developed in the 21st century, specifically seen recently in the entrance of robots. The advent of robots for precision tasks such as in medical robotics has introduced a problem in computer-controlled motion, in that it required low backlash mechanical transmissions in the kinematic chains that link motors to the driven elements or the end-effectors in the chain. If there is backlash present in the mechanical motion, kinematic errors and possible dynamics will be effected, as the driving element does not exactly follow the motion of the motor. These errors impact kinematic performance of these robots, which can have catastrophic implications in medical robots. However, a solution to this problem is difficult as gears in these robots drive mechanical motion and these gears have backlash that is hard to control. Therefore, there is a need for a mechanical transmission that either minimizes backlash or is backlash free. Specifically, a solution may arise by using gearheads, which are mechanical transmissions attached to motors, to reduce speed and increase torque through a transmission ratio. Moreover, there is a need to implement the gearheads into compact assembly to satisfy the requirements of the task environment, for example being restricted by anatomic constraints in the case of surgical robots.
Technology Overview
The inventors have proposed a novel way of mounting a harmonic drive gearhead to a cylindrically shaped motor that reduces the overall size of the actuator assembly, which has been the limiting step in application. They have mounted the motor within the harmonic drive and its bearings, specifically just as long as the actuator and as large as the harmonic drive by themselves. They have proposed a redesign of the harmonic drive to optimize the space at the center of the harmonic drive to accommodate the motor within. This harmonic drive includes a bell shaped component that, although previously existing, is improved by allowing the two separate components to perform separate function. This harmonic actuator gearhead provides a solution to minimize backlash in the mechanical kinematic chain in computer controlled mechanical motion, allowing for more precise and accurate motion that can applied to several applications but was specifically designed for medical robotics.
Stage of Development
The inventors have designed, built, and tested the novel harmonic actuator gearhead device and included it with several medical robots.
