Development of impedance-sensing technology and an intelligent control system for robot-automated processing of flexible and natural objects.

摘要

General tasks of robotic manipulation may be broadly categorized as gross/hard manipulation and flexible manipulation. In gross/hard manipulation, robotic tasks are defined by motion commands based on predefined and precise positions. In flexible manipulation, as defined in this thesis, robot motion cannot be pre-defined in terms of precise positions and motions, due to task uncertainties.; Focus of the present research is on fine/flexible manipulation, which is important in robotic processing of flexible and inhomogeneous, natural materials, such as fish and meat, where, the detection of material properties and transition regions in the processed object is usually important for high-level, intelligent task control.; The main goals of, the present research are threefold; (1) investigate and develop an impedance-based task sensing method for flexible manipulation, (2) investigate, design, and develop a control architecture that has the capability of on-line task monitoring and interpretation, high-level feedback of information, and knowledge-based decision making, which is suitable for executing flexible manipulation of robotic processes, and (3) implement and evaluate the developed sensing and control system technologies with regard to practical applications. To achieve these objectives, the following tasks are carried out: Analytical framework for dynamics, sensing, and control . Models are formulated for robot dynamics and process impedance, with linearizing feedback and task separation for gross motions and fine manipulation.; Impedance sensing technologies. Methods of estimating mechanical impedance at the process interface of a robotic processing task are developed, which use actuator effort and the joint motion signals as the input information to the estimator.; Control architecture. The use of mechanical impedance as intended in the present research requires feedback of sensory information to the task control level. To accommodate this and other requirements of flexible manipulation, a real-time open-architecture control system (ROACS) is designed and developed in this thesis.; Design of implementation model and system prototyping. A client-server type robot control system is designed and developed that satisfies the ROACS model. The system contains three servers: servo controller, motion planner, and data analyzer; and three client applications: intelligent task control, information updating module, and a graphics user interface which includes a robot control shell and a real-time task language (RTTL) as developed in the present research.; The developed robot controller is implemented for operation with a Puma 560 robot in the Industrial Automation Laboratory. A salmon-slicing task, which produces boneless salmon steaks, is performed by using the developed system, to demonstrate the performance of ROACS and the feasibility of employing the developed technology in an industrial application. (Abstract shortened by UMI.)