We present the conceptual design and initial development of the hysteretic deformable mirror (HDM). The HDM is a completely new approach to the design and operation of deformable mirrors (DMs) for wavefront correction in advanced imaging systems. The key technology breakthrough is the application of highly hysteretic piezoelectric material in combination with a simple electrode layout to efficiently define single actuator pixels. The set-and-forget nature of the HDM, which is based on the large remnant deformation of the newly developed piezomaterial, facilitates the use of time division multiplexing to address the single pixels without the need for high update frequencies to avoid pixel drift. This, in combination with the simple electrode layout, paves the way for upscaling to extremely high pixel numbers (≥128 × 128) and pixel density (100∕mm 2 ) DMs, which is of great importance for high spatial frequency wavefront correction in some of the most advanced imaging systems in the world.
We present modeling and analysis of a hysteretic deformable mirror where the facesheet interacts with a continuous layer of piezoelectric material that can be actuated distributively by a matrix of electrodes through multiplexing. Moreover, a method to calculate the actuator influence functions is described considering the particular arrangement of electrodes. The results are presented in a semi-analytical model to describe the facesheet's deformation caused by a high-density array of actuators, and validated in a simulation. The proposed modeling of an interconnection layout of electrodes is used to determine the optimal pressures the actuators must exert to achieve a desired surface deformation.
Bio-inspired robotic designs introducing and benefiting from morphological aspects present in animals allowed the generation of fast, robust and energy efficient locomotion. We used engineering tools and interdisciplinary knowledge transferred from biology to build low-cost robots able to achieve a certain level of versatility. Serval, a compliant quadruped robot with actuated spine and high range of motion in all joints was developed to address the question of what mechatronic complexity is needed to achieve rich motion skills. In our experiments, the robot presented a high level of versatility (number of skills) at medium speed, with a minimal control effort and, in this article, no usage of its spine. Implementing a basic kinematics-duplication from dogs, we found strengths to emphasize, weaknesses to correct and made Serval ready for future attempts to achieve more agile locomotion. In particular, we investigated the following skills: trot, bound (crouched), sidestep, turn with a radius, ascend slopes including flat ground transition, perform single and double step-downs, fall, trot over bumpy terrain, lie/sit down, and stand up.
Bio-inspired robotic designs introducing and benefiting from morphological aspects present in animals allowed the generation of fast, robust, and energy-efficient locomotion. We used engineering tools and interdisciplinary knowledge transferred from biology to build low-cost robots, able to achieve a certain level of versatility. Serval, a compliant quadruped robot with actuated spine and high range of motion in all joints, was developed to address the question of what mechatronic complexity is needed to achieve rich motion skills. In our experiments, the robot presented a high level of versatility (number of skills) at medium speed, with a minimal control effort and, in this article, no usage of its spine. Implementing a basic kinematics-duplication from dogs, we found strengths to emphasize, weaknesses to correct, and made Serval ready for future attempts to achieve more agile locomotion. In particular, we investigated the following skills: walk, trot, gallop, bound (crouched), sidestep, turn with a radius, ascend slopes including flat ground transition, perform single and double step-downs, fall, trot over bumpy terrain, lie/sit down, and stand up.
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