This work examined the design, fabrication, and testing of a bio-mimetic MEMS earthworm crawler with external actuators. The micro-earthworm consisted of a passive mobile shuttle with two flexible diamond shaped segments; each segment was independently squeezed by a pair of stationary chevron-shaped thermal actuators. By applying a specific sequence of squeezes to the earthworm segments, the shuttle could be driven backwards or forwards. Unlike existing inchworm drives, which use separate clamping and thrusting motors, the earthworm motor applies only clamping forces and lateral thrust is produced by the shuttle’s compliant geometry. A study of existing crawler work was performed; to the author’s knowledge, this was the first micro-crawler to achieve both clamping force and lateral motion using the same actuators. The earthworm assembly was fabricated using the POLYMUMPs process, with planar dimensions of 400 µm wide by 800 µm long. The stationary earthworm motors operated within the range of 4-9 V, and 0-10 kHz; these motors provided a maximum shuttle range of motion of 350 µm (~half the size of the device), a maximum shuttle speed of 17,000 µm /s at 10 kHz, and a maximum DC shuttle force of 80 µN. The shuttle speed was found to vary linearly with both input voltage and input frequency; the shuttle force was found to vary linearly with actuator voltage. The tested design had higher force, range, and speed (per device footprint) than most other existing designs. Future work recommendations included the implementation of multiple motors and a closed loop control system to allow an indefinite range of motion, as well as the investigation of a two degree of freedom crawler. / THE DESIGN AND TESTING OF A BIO-INSPIRED HIGH PRECISION, HIGH SPEED, LONG RANGE PERISTALTIC MICRO-MOTOR

<p>Recent developments in thin film synthesis of diamond have facilitated a host of new technical applications. These are motivated by the many attractive properties of diamond, for example high hardness, chemical inertness, transparency and heat conductivity. Unfortunately, these properties also make it difficult to fashion complex geometries. Other problems are the severely limited choice of suitable substrate materials and large surface roughness. To reduce these complications, a technology denoted <i>replication and bodybuilding</i> has been developed. The basic principle is to grow the diamond film onto a mold and then build a mechanical support on top of the diamond film. Then the mold is removed. Thereby, a diamond surface with the desired 3D geometry and the same surface roughness as the mold is created.</p><p>Three potential applications for devices built using the replication and bodybuilding concept have been explored. <i>Grinding tools for hard materials</i> have proved superior to conventional technology in rate of removal as well as in resulting surface finish. Diamond surfaces have also been crafted into <i>ultra-durable dies for injection molding</i> of hard particle reinforced polymers. Initial testing of an <i>abrasive diamond device</i>, intended to make CMP processes more economical and easier to control has successfully been carried out.</p><p>Diamond and diamond-like carbon is well-known for being “low-friction materials”, but are here demonstrated to actually be “high-friction materials” with the ability to disguise themselves in certain environments, most notably with the aid of water molecules. The mechanisms involved in these variations have been investigated. Using NEXAFS it is shown that high friction sliding is accompanied by changes in the material structure. These changes are induced by surface roughness as well as by strong adhesive forces.</p><p>Highly hydrogenated carbon coatings, on the other hand, affording super-low friction coefficients (<0.01) under certain circumstances, will suffer an increase in friction in the presence of water.</p>

Recent developments in thin film synthesis of diamond have facilitated a host of new technical applications. These are motivated by the many attractive properties of diamond, for example high hardness, chemical inertness, transparency and heat conductivity. Unfortunately, these properties also make it difficult to fashion complex geometries. Other problems are the severely limited choice of suitable substrate materials and large surface roughness. To reduce these complications, a technology denoted replication and bodybuilding has been developed. The basic principle is to grow the diamond film onto a mold and then build a mechanical support on top of the diamond film. Then the mold is removed. Thereby, a diamond surface with the desired 3D geometry and the same surface roughness as the mold is created. Three potential applications for devices built using the replication and bodybuilding concept have been explored. Grinding tools for hard materials have proved superior to conventional technology in rate of removal as well as in resulting surface finish. Diamond surfaces have also been crafted into ultra-durable dies for injection molding of hard particle reinforced polymers. Initial testing of an abrasive diamond device, intended to make CMP processes more economical and easier to control has successfully been carried out. Diamond and diamond-like carbon is well-known for being “low-friction materials”, but are here demonstrated to actually be “high-friction materials” with the ability to disguise themselves in certain environments, most notably with the aid of water molecules. The mechanisms involved in these variations have been investigated. Using NEXAFS it is shown that high friction sliding is accompanied by changes in the material structure. These changes are induced by surface roughness as well as by strong adhesive forces. Highly hydrogenated carbon coatings, on the other hand, affording super-low friction coefficients (&lt;0.01) under certain circumstances, will suffer an increase in friction in the presence of water.

<p>Microengineering has developed a broad range of production techniques to reduce size, increase throughput, and reduce cost of electrical and mechanical devices. The miniaturisation has also entailed entirely new opportunities.</p><p>In this work, a piezoresistive silicon sensor measuring mechanical deformation has been designed and fabricated with the help of microengineering. Due to the large variety of used processes, this device can serve as a survey of techniques in this field. Four basic process categories are recognised: additive, subtractive, modifying, and joining methods.</p><p>The last category, joining methods, has previously been the least investigated, especially when it comes to compatibility with the other categories. The adaptability of wet chemical etching to established silicon wafer bonding technique has been investigated. Further, phenomena related to oxygen plasma pre-treatment for direct bonding has been investigated by blister bond adhesion tests, X-ray photoelectron spectroscopy, and atomic force microscopy.</p><p>Wafer bonding has been adapted to monocrystalline quartz. For wet chemical pre-treatment, characteristics specific for quartz raise obstacles. Problems with limited allowable annealing temperature, low permeability of water released in the bond at annealing, and electrostatic bonding of particles to the quartz surface, have been studied and overcome. The influence of internal bond interfaces on resonators has been investigated.</p><p>Chemical polishing of quartz by ammonium bifluoride has been experimentally investigated at high temperatures and concentrations. Chemometrical methods were used to search for optimum conditions giving the lowest surface roughness. These extreme conditions showed no extra advantages.</p><p>Adhesion quantification methods for wafer bonding have been comprehensively reviewed, and augmentations have been suggested. The improved techniques’ usefulness for three areas of use has been forecasted: general understanding, bonding scheme optimisation, and quality control. It was shown that the quality of measurements of all commonly used methods could be dramatically improved by small means.</p>

Microengineering has developed a broad range of production techniques to reduce size, increase throughput, and reduce cost of electrical and mechanical devices. The miniaturisation has also entailed entirely new opportunities. In this work, a piezoresistive silicon sensor measuring mechanical deformation has been designed and fabricated with the help of microengineering. Due to the large variety of used processes, this device can serve as a survey of techniques in this field. Four basic process categories are recognised: additive, subtractive, modifying, and joining methods. The last category, joining methods, has previously been the least investigated, especially when it comes to compatibility with the other categories. The adaptability of wet chemical etching to established silicon wafer bonding technique has been investigated. Further, phenomena related to oxygen plasma pre-treatment for direct bonding has been investigated by blister bond adhesion tests, X-ray photoelectron spectroscopy, and atomic force microscopy. Wafer bonding has been adapted to monocrystalline quartz. For wet chemical pre-treatment, characteristics specific for quartz raise obstacles. Problems with limited allowable annealing temperature, low permeability of water released in the bond at annealing, and electrostatic bonding of particles to the quartz surface, have been studied and overcome. The influence of internal bond interfaces on resonators has been investigated. Chemical polishing of quartz by ammonium bifluoride has been experimentally investigated at high temperatures and concentrations. Chemometrical methods were used to search for optimum conditions giving the lowest surface roughness. These extreme conditions showed no extra advantages. Adhesion quantification methods for wafer bonding have been comprehensively reviewed, and augmentations have been suggested. The improved techniques’ usefulness for three areas of use has been forecasted: general understanding, bonding scheme optimisation, and quality control. It was shown that the quality of measurements of all commonly used methods could be dramatically improved by small means.

This thesis describes and evaluates the design of nanospacecraft based on advanced multifunctional microsystems building blocks. These systems bring substantial improvements of the performance of nanosatellites and enable new space exploration, e.g. interplanetary science missions using minute space probes. Microsystems, or microelectromechanical systems, allows for extreme miniaturization using heritage from IC industry. Reducing mass and volume of spacecraft gives large savings in terms of launch costs. Definition and categorization of system and module level features in multifunctional microsystems are used to derive a spacecraft optimization algorithm which is compatible with commonly used concurrent engineering methods. The miniaturization of modules enables modular spacecraft architectures comprising powerful multifunctional microsystems, which are applicable to satellites between 10 and 1000’s of kg. This kind of complete spacecraft architecture has been developed for the NanoSpace-1 technology demonstrator satellite. The spacecraft bus uses multifunctional design to enable distributed intelligence and autonomy, graceful degradation, functional surfaces, and distributed power systems. The increase in performance of the new spacecraft architecture as compared with conventional nanosatellites is orders of magnitudes in terms of power storage, scientific payload mass ratio, pointing stabilization, and long time space operation. This high-performance system-of-microsystems architecture has been successfully employed on two space robotic concepts: a miniaturized submersible vehicle for Jupiter’s Moon Europa and a miniaturized spherical robot. The submersible is enabled by miniaturization of electronics into 3-dimensional, vertically integrated multi-chip-modules together with new interconnection methods. These technologies enabled the submersible vehicle tube-shaped design within 20 cm length and 5 cm diameter. The spherical rover was developed for long range and networked science investigations of interplanetary bodies. The rover weighs 3.5 kg and is shown to endure direct reentry on Mars, which increases the ratio between the landed mobile payload mass and the initial mass in Mars orbit by a factor of 18.