This invention relates to a remote control apparatus and, more particularly, to an axial alignment aid and related method for facilitating remote control operations.
Many attempts have been made to remotely align two objects in space. For example, the National Aeronautics and Space Administration (NASA) has done extensive work in the area of docking spacecraft. As discussed in "Communications, Tracking and Docking on the Space Station," by Erwin et al., published by the Institute of Electrical and Electronics Engineers (1982), NASA has proposed the use of a triangular array of reflectors on a passive target to define a plane and facilitate docking of an active vehicle thereto. Sequential tracking of each reflector from the active vehicle in space allows altitude determination between the active vehicle and the passive target. However, this triangular reflector system necessarily employs computers, thus making it extremely complex. In addition, the system is incapable of accurately and remotely aligning an axis of importance of the passive target to an axis of importance of the active vehicle to allow "soft" docking.
Other attempts have been made to accurately align or dock one object relative to another. For example, U.S. Pat. No. 3,269,254, issued to COPPER et al., discloses an optical apparatus including: a light source; a beam splitting cube; a lens system and a grated mirror, all on one side of the light source; and a measuring reticle having coordinates thereon located on the opposite side of the light source. Light from the light source is directed by the beam splitting cube through the lens system. The light then reflects off of the mirror to again pass through the lens system and the beam splitting cube. Finally, an image is formed at the measuring reticle to provide information regarding orientation of a body o which the mirror is attached, as defined by azimuth, pitch and roll. Because the mirror described in this patent is flat, if the beam of light directed at the mirror is too far off-axis, the light beam can be reflected too far off, thus preventing the formation of an image at the measuring reticle. As a result, an accurate off-axis measure is not available with this patented device. Further, this patented device is sensitive to distance, i.e., the effectiveness of the device is lessened as the measuring reticle and the mirror are placed farther apart. Finally, this device is not adapted to allow docking of one member relative to another member.
In addition, U.S. Pat. No. 2,352,179, issued to BOSLEY, uses a set of four photo-electric cells as detectors to provide information as to the orientation of a lens. That is, the set of cells indicates from one perspective how far away one is from a target; but such detectors cannot accurately indicate the axis that is defined by the target. Therefore, such a system using a set of four detectors is also incapable of allowing on-axis docking alignment of one object relative to another.
One application where remote control docking would be particularly important is in nuclear powered steam generators. For example, performing a task within the steam generator with a tool or end effector and a robot for receiving the end effector is currently performed as follows. A first set of cameras positioned in the steam generator allow a conventional robot arm known as ROSA (remote operation service arm) to be remotely viewed and moved to the general vicinity of one or several end effectors positioned in the steam generator. These cameras, however, cannot accurately and automatically align the respective axes of the chosen end effector and ROSA, i.e., cannot reliably effect docking and attachment.
The end effector also has a camera mounted thereon which ultimately is used to remotely view the worksite during performance of the task via a conventional feedback system using a remote viewing station, robotic controls and means for moving ROSA.
As a result, a man must be introduced into the steam generator to manually align and attach the end effector to ROSA. However, due to the potential radiation exposure, tedious alignment and attachment steps necessary, and the relatively heavy members being manipulated, it is desired to make the alignment and attachment of end effectors to ROSA in the steam generator an entirely remotely controlled operation having high reliability A more general need also exists for a means by which accurate alignment can be made between two important axes of respective docking members using single perspective visual guidance.