A novel concept for large aperture lightweight deformable mirrors is presented. This new concept is based on using a flexure-hinged truss substrate as opposed to monolithic substrates used in all past and current deformable mirror technologies. With its ability to deform in tangential as well as normal directions, this new concept solves the problem of coefficient of thermal expansion (CTE) mismatch between face sheet and substrate. It takes advantage of the newly emerging face sheet technologies such as nanolaminates that produce extremely lightweight optical quality face sheets and require very small forces to deform them. It also provides rigidity to the thin face sheet mirror, necessary for the uniqueness of response to actuator commands and for tolerance to disturbances. Any stresses in substrate structure are mainly limited to those induced by the forces in the face sheet itself, which are small in the new lightweight face sheets. The dynamic range of deformation is limited only by the actuator stroke, and not by the stresses induced in the substrate. Therefore it drives the actuator design to small force large stroke actuators, as opposed to the current designs that use large force small stroke moment actuators.
This work demonstrates a vision-based control technique that does not require robot or vision system calibration. There are two distinct advantages: first, the approach is generic and can be applied to a variety of systems; second, calibration is unnecessary after a reconfiguration or disturbance to the robotic workcell. It has the potential to provide a low-cost, low-maintenance automation solution for unstructured industries and environments. The robot end- effector tracks a moving target using a novel dynamic quasi- Newton control was formulated in the image plane and on-line Jacobian estimation using either a dynamic Broyden's method or a dynamic recursive least squares algorithm. Experimental results demonstrate convergent and stable control of an uncalibrated manipulator tracking a moving target. The method is shown to be robust to system reconfiguration such as modifications to the position and orientation of the camera.
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