|BOSTELMAN, ROGER - US Department Of Commerce|
Submitted to: International Conference on Intelligent Robots and Systems (IROS)
Publication Type: Proceedings
Publication Acceptance Date: 5/18/2010
Publication Date: N/A
Interpretive Summary: Many types of field research, including agronomy, natural resource management, ecology and environmental science, present situations that arise where researchers need to make measurements at precise locations over large field areas (e.g., 200 to 300 ft across). Often, contact with the surface of the ground or the plants must be minimized to avoid introducing artifacts such as by compacting the soil or damaging the plants. This makes it impossible to use tractors or other wheeled vehicles and even frequent entry by people is undesirable. Many types of sensors, imagers and tools are available that can perform the required measurements or manipulations. The key obstacle for more efficient research capability is positioning the equipment precisely and quickly anywhere in a given field. This paper describes the design and early-stage testing of a cable-based system, which we call the “Large-area Overhead Manipulator for Access of Fields” or “LOMAF.” The basic configuration is to suspend an instrument platform from three or more winch-controlled cables that run through pulleys attached to the tops of posts positioned at the corners of the field. Because these cables do not provide downward force, additional cables, termed “downhauls”, are required to maintain the platform level (or at any desired inclination). The downhauls are attached below the desired height of the platform to provide the downward control. The invention provides options for configurations with downhauls that adequately control the platform inclination and position while maximizing the usable area between the posts and minimizing the required height of the posts. The cables are independently controlled by hand or powered winches through the use of an operator-controlled joystick or unit or by a computer. Numerous applications in agricultural research can be envisaged ranging from identification of novel plant types or traits (“phenomics”) to disease and pest epidemiology to management of within-field variation in yield (“precision agriculture”), all of which should ultimately lead to improved productivity or reductions in adverse impacts of agriculture on the environment. The LOMAF also appears suitable for scanning mine fields, environmental cleanup, material handling, building surface access, as well as for numerous other options.
Technical Abstract: Multi-axis, cable-driven manipulators have evolved over many years providing large area suspended platform access, programmability, relatively rigid and flexibly-positioned platform control and full six degree of freedom (DOF) manipulation of sensors and tools. We describe innovations for a new six DOF manipulator, called ‘Large-area Overhead Manipulator for Access of Fields (LOMAF)’ that is highly scalable and provides access to areas that can measure from several square centimeters to several hectares and can traverse level or irregular terrain, including vertical surfaces. Two scaled prototypes have been developed and tested providing the basis for designing a much larger, computer-controlled system. The LOMAF design, prototypes, tests, results and suggested applications are presented in this paper.