| Description |
Human motion capture has a wide variety of applications in the entertainment and medical industries. Actors using motion capture devices provide realistic motion inputs for cartoons, virtual reality environments™, and computer and robot animation, resulting in tremendous time and cost savings. Medical applications include range of motion studies to diagnose injuries or identify insurance fraud, biomechanics studies of human performance and calculation of joint stresses, and ergonomics studies of humans in the workplace. There are common problems facing all methods of motion capture: how to attach the device to the individual's limbs, what sensors to use and how to use them, how to transmit data and convert it into a usable form, calibration of the device, data display, user comfort, and device reliability. Even when these problems are addressed, there are limitations in the kinematic model as well as human joint anomalies that make all methods imperfect. Currently, there are optical, magnetic, and exoskeletal devices for motion capture that vary widely in terms of performance, cost and limitations. Considering the likely environment and performance needs of the Sarcos Research Corporation, the SenSuit™ was built as an exoskeletal device. Creation of the SenSuit™ involved overcoming three major hurdles: the soft tissue interface, accurate joint angle measurement, and sensor design. The soft tissue interface is the series of rigid plates that are placed on skeletal landmarks located near the surface of the user's skin. Through appropriate location of the plates, a consistent, stable fit to the skeleton was achieved for users, which enhanced joint angle data. Accurate joint angle measurements were achieved either by aligning sensor rotation centers with approximate joint rotation centers or by computationally transforming the outputs of three degree of freedom sensor clusters located to reduce nonlinearities. A software routine allowed for quick, linear calibration of the individual. Joint angle sensors were designed that were small, linear, robust, and resistant to wear and contaminants. The SenSuit™ has proven itself both comfortable and reliable. It has been thoroughly tested in real-world applications, including real-time driving of graphical and robotic figures, as well as the programming of various robotic figures. |
