Abstract: A method and system for routing a digital probe which signals either a triggered or non-triggered state to continuously scan a part surface without having to return to a rest position each time the probe is triggered. The probe is carried by manufacturing equipment capable of moving in response to control signals and providing manufacturing equipment feedback signals indicating the current position of the probe. Continuous movement of the digital probe is achieved by testing the probe to determine if it is triggered or not at a series of closely spaced time intervals, and rotating a move vector (corresponding to desired probe velocity) in each computation cycle to alter the probe trajectory as a function of the operating state of the probe and its position during the previous computation cycle. These techniques allow relatively inexpensive digital probing systems to gather data at speeds comparable to those of much more expensive analog systems.
Abstract: In a machine tool, a component such as a grinding wheel acts on a workpiece to form the latter into a circularly asymmetric shape, for example, a crankpin. Movement of the grinding wheel is controlled by a control signal which is derived from theoretical relative positions and positional velocities of the grinding wheel relative to the workpiece. In the course of at least one revolution of the workpiece, the respective positions of the grinding wheel relative to the workpiece are measured for each of a succession of angular positions of the workpiece. The measured positions are compared with corresponding theoretical positions and data indicative of any differences are stored, and then used to modify the control signal during a subsequent revolution of the workpiece so as to compensate for any of said differences and thereby reduce the magnitude of any error which would have resulted from the measured positional differences.
Type:
Grant
Filed:
November 24, 1997
Date of Patent:
March 14, 2000
Assignee:
Unova U.K. Limited
Inventors:
John David Pickles, Selwyn Jonathan Griffiths
Abstract: A device for tracking the translational and rotational displacement of an object having two degrees of freedom using a single point of contact with the object. The device is particularly useful in a catheter simulation device for surgery and interventional radiology applications. A spherical contact member is mounted for free rotation about all axes in force-transmitting contact with the surface of the object and a pair of shafts are mounted in tangential engagement with the spherical member to reflect the displacement imparted to the object relative to a reference position. This arrangement provides simultaneous tracking of the combined translational and rotational displacement of the object. Measuring the displacement of the object and a haptic applicator are included such that a load may be applied to the object to precisely control the degree of force required to cause displacement of the object.
Type:
Grant
Filed:
January 12, 1998
Date of Patent:
March 14, 2000
Assignee:
Bertec Corporation
Inventors:
Scott Z. Barnes, Douglas R. Morr, Necip Berme