(Georgia Institute of Technology, 2009-10)
Humphreys, Heather C.; Book, Wayne J.; Huggins, James D.
An advanced backhoe user interface has been developed which uses coordinated control with haptic feedback. Results indicate that the coordinated control provides more intuitive operation that is easy to learn, and the haptic feedback also relays meaningful information back to the user in the form of force signals from digging forces and system limitations. However, results show that the current system has significant problems with biodynamic feedthrough, where the motion of the controlled device excites motion of the operator, resulting in undesirable forces applied to the input device and control performance degradation. This unwanted input is difficult to decouple from the intentional operator input in experiments. This research presents an investigation on the effects of biodynamic feedthrough on this particular backhoe control system, using system identification to empirically define models to represent each component. These models are used for a preliminary simulation study on potential methods for biodynamic feedthrough compensation.
(Georgia Institute of Technology, 2009-07)
Winck, Ryder C.; Dickerson, Stephen L.; Huggins, James D.; Book, Wayne J.
This paper describes a novel fabric manipulation method for fabric control during the sewing process. It addresses issues with past attempts concerning fabric position and tension control. The method described involves replacing the current sewing feed mechanism with a servo controlled manipulator to both feed and control the fabric. The manipulator is coupled with a machine vision system that tracks the threads of the fabric to provide real-time position control that is robust with respect to fabric deformations. A prototype of the manipulator is used to demonstrate the feasibility of the concept, reaching accelerations up to 27 g’s and following a closed loop trajectory with open loop control while operating in coordination with an industrial sewing machine. The system described also offers a general solution to high accuracy and high acceleration position control systems.