Going beyond naturally occurring materials, Metamaterials exploit a design at the microscale resulting in macroscopic behaviour, to achieve different or even new properties that can have a wide range of applications. By incorporating sensors, actuators and control, Robotic Metamaterials can achieve even more extremely different behaviour such as odd elasticity. By using local control and non-reciprocal couplings between actuators, an asymmetric elastic response can be achieved. Due to the non-conservative nature of this coupling, the system has a tendency to cycle and give rise to complex behaviours such as locomotion. Through simple and localized control, complex material behaviour is achieved, where the body is performing the computation and no complex control or computations systems are required. In this work, a new unit cell for a metamaterial that achieves this odd elasticity is designed, manufactured, and finally tested. The unit cell consists of 3 hexagonal mechanisms with compliant joints and a linear actuator inside and is locally controlled. By using a novel Actuator design and engineering principles such as compliant mechanisms, a unit cell design is achieved that has 10 times smaller scale per area and 15 times higher strength-to-weight ratio compared to existing work. Finally, this unit cell was characterized and combined into a larger lattice showcasing the possibilities for future research into the behaviour of odd elastic metamaterials.

Linear time-invariant controllers are undoubtedly the most popular type of regulators used in industrial applications, with the overwhelming majority of companies employing them. The reason is mainly given by their simple design methods. In particular, frequency domain predictive performance analysis and stability methods allow the use of loopshaping techniques. Nevertheless, inherent limitations affecting linear controllers pose constraints on their performance that can only be overcome through the adoption of nonlinear control schemes. Promising findings in recent literature suggest that with reset control, a nonlinear control technique, it is possible to overcome these limitations. At the same time, reset control could also potentially allow the use of straightforward design techniques, thus making it suitable for industrial applications. The main goal of this work is to bring together the different concepts scattered in literature, in order to initialize the construction of a general framework for the design and analysis of reset controllers suitable for an industrial setting. Tuning guidelines for different structures using two classes of reset controllers, the first order reset element and the proportional Clegg integrator, were presented. Two frequency domain methods, namely open-loop higher order sinusoidal input describing functions (HOSIDFs) and pseudosensitivities computed through analytically derived (approximate) closed-loop HOSIDFs, were effectively applied to predict steady-state performance. Stability was (when possible) analysed through the frequency domain Nyquist stability vector method, which could also be implemented in the design process. The frequency domain analysis methods allowed the use of loopshaping techniques similar to LTI control for the design of reset controllers. The controllers, implemented digitally on an ASM Pacific Technology wire bonding machine, show that through reset control a significant decrease in the root mean square of the settling error compared to an equivalent LTI controller could be achieved. The existing frequency domain analysis methods, its straightforward implementation and the increase in performance achieved in experiments validate the potential of reset control as a suitable alternative to LTI control for industry. Nevertheless, limitations in the explored reset control structures still exist and further work is required in order to achieve the full potential that this technique has to offer.

In this paper, the implementation of an active unit-cell metamaterial used for vibration control is discussed. The active unit-cell metamaterial is designed for implementation in a hexapod strut. As each of the unit-cells can be sensed and actuated, over-sensing and over-actuation are introduced in the system. This can be used to create vibration isolation behaviour. This is done using the interaction between the unit-cells. Using the commercial FEM software COMSOL, the amount of unit-cells used in the strut is determined. By looking at the transmissibility of the system, the required controllers are also determined. The presented unit-cell design makes use of simple active damping controllers in order to improve control flexibility for different systems. The system is validated using a realistic model made in the commercial software Simulink. The model includes sensor dynamics, sensor noise, and a realistic disturbance. By looking at the transmissibility and the disturbance response, the system is compared to an existing solution. Compared to the existing solution, the transmissibility is lowered by at minimum 13 dB in the frequency range of interest. The transmitted disturbance is lowered roughly 20 times with roughly 6.6 times bigger required control effort.

With the requirements for CubeSats increasing, a push towards utilizing high­performance equipment has never been greater. Incorporating these equipment in an environment that is cost­, space­ and power­constrained, is challenging. Simultaneously, high­performance equipment require high pointing­accuracy and low­jitter. This thesis proposes the use of a cost­effective reaction­wheel, which utilizes three hall­sensors for accurate attitude­control. Additionally, the requirements state that the reaction­wheel operates in the low­speed region, whilst tracking low­acceleration commands. For this, a controller­structure is designed, simulated & implemented in order to provide accurate angular­velocity estimates at a constant rate. Whilst the angular­velocity estimates are within 1% of the measurements, the angular­acceleration tracking performance relies greatly on the noise of the reaction­wheel torque­friction. Nonetheless, the angular­acceleration mean error was found to be 0.005 RPM/s, with a variance of 0.3 RPM/s on a 0.01 RPM/s reference

Vibrations and disturbances are becoming more of a concern as lightweight, flexible structures in high-tech systems are pushed towards faster speeds and higher precision. Active Vibration Control (AVC) methods have been effectively used to attenuate vibrations and increase the bandwidth of these systems. With the miniaturisation of electronics, an increasing amount of sensor and actuator pairs can be used for AVC applications. Not only does this allow for higher active damping, it also grants more flexibility in terms of control. This trend has led to the study of robotic metamaterials and meta-structures: large-scale engineered materials build out of a repeating pattern of unit cells, where each unit cell contains a sensor, actuator and sometimes even a computing unit. The optimal control architecture to use for these systems is a difficult dilemma, since decentralised and centralised control schemes both have fundamental trade-offs in terms of performance and scalability. In this paper we study distributed control, a promising middle-ground solution that is hardly used in AVC applications. We show with the use of LQR that a distributed control architecture can achieve optimal performance in the low-frequency range for robotic materials with relative measurements. Additionally, the actuators use lower maximum control forces and a distributed control architecture remains scalable for implementation in large-scale systems. In this paper the robotic cantilever beam is studied as a specific example as it represent many typical high-tech applications. Furthermore, implications on periodic robotic meta-structures are made using LQR in the Spatial Fourier Domain.

To improve Active Vibration control methods like Independent Modal Space Control (IMSC), an estimate of the modal contribution of vibrational eigenmodes of compliant structures is required. In this work, three Recursive Bayesian input and state estimation algorithms previously introduced in civil engineering are evaluated for use on on high-tech compliant mechanisms to estimate modal contributions for use in Active Vibration Control. The difference in environment when applying these algorithms from civil engineering into high-tech compliant motion stages allows for a significantly different sensor configuration possibly improving estimation performance. The three algorithms, namely, the Augmented Kalman Filter (AKF), Dual Kalman Filter (DKF) and Gilijns de Moor Filter (GDF) are implemented in simulation and on an experimental compliant motion stage setup. The modal contributions of the guidance flexures are estimated through a noisy acceleration measurement at the stage and strain measurement at the flexure base. For validation, the filters are evaluated on overall fit quality and system acceleration dependency through the quality of estimation of the flexure tip location. The DKF is shown worst performance with lowest fit scores overall and high acceleration dependency while the AKF and GDF perform comparably well. The GDF is shown to transmit less noise into the estimate however, and thus performed overall best.

This thesis presents the development of a contactless sensing system and the dynamic evaluation of an air-bearing based precision wafer positioning system. The contactless positioning stage is a response to the trend seen in the high-tech industry, with the substrates becoming thinner and larger to reduce the cost and increase the yield. With contactless handling, it is possible to avoid damage and contamination. The system works by floating the substrate on a thin film of air. A viscous traction force is applied on the substrate by steering the airflow. A cascaded control structure has been implemented to the contactless positioning system, where the Inner Loop Controller (ILC) controls the actuator which steers the airflow and the Outer Loop Controller (OLC) controls the position of the substrate by controlling the reference of the ILC. The dynamics of the ILC are evaluated and optimized for the performance of the positioning of the substrate. For the OLC a linear charge-coupled device (CCD) has been implemented as a contactless sensing system. The sensing concept is implemented in the contactless actuation system and the results are presented.

In the industry motion systems with electric motors are used for transporting and positioning thin flexible substrates at high throughput rates. A possible alternative actuation solution could be to apply contactless air film actuators which make use of air bearing principles. The air film actuators use a thin film of air to levitate and propel a substrate. The main advantage of such a technique is that it actuates directly on the substrate and therefore eliminates the moving mass of a carrier. This drastically reduces the actuation force required to accelerate the substrate, which reduces unwanted deformations and excitations of the machine frame. Because the substrate is not in direct contact with the bearing surface, the substrate does not experience any wear, stiction or backlash effects. In this project a demonstrator with opposed air film actuators is designed and manufactured to actuate a flexible substrate in one degree of freedom. To predict the performance of the motion system, the air film actuators are modelled with the use of the Reynolds equation for compressible air, determined both analytically and numerically. The demonstrator consists of two manifolds with their bearing surfaces facing each other and where a substrate is placed between the two bearing surfaces. By using pressurized air, the substrate can be levitated between the two bearing surfaces. By controlling proportional valves, the substrate can be moved in negative or positive x-direction. The theoretical models show good resemblance with the measurement results. However, the substrate vibrated and did not float fully contactless between the two bearing surfaces. Based on these results, improvements can be made on the bearing function of the system, but the demonstrator shows promising results for actuating substrates with large accelerations and fast responses.

Computer vision has been on the rise over the last decades. The applications of computer vision are mostly found within the domain of robotics and Unmanned Aerial Vehicle's. The use of computer visions in precision industry is new and offers both opportunities and challenges. In high performance precision systems the demands on sensors is set high in terms of precision, delay and sample rate. In previous work a computer vision sensor was developed for the control of a microscopy stage. This development opened a path for computer vision sensors in precision systems. However, the limitations of computer vision sensors are challenging in the domain of control. A computer vision sensor needs to process an image before it can estimate the position of an object. This processing requires time which introduces a time delay into the control system. Due to the nature of the computer vision algorithm and computing devices, the delay in the sensor is time varying. Furthermore, since a controller typically requires a tenfold sample rate of the control bandwidth the limited frame rate of computer vision sensors imposes additional challenges. In previous work, the delay and limited sample rate of the computer vision sensor limited the control bandwidth of a microscopy to 0.87Hz in translational range. Since high performance precision systems require higher bandwidths a new computer vision sensor is developed in this thesis. An existing microscopy stage is used to test the performance of a computer vision sensor. Ground vibrations in a laboratory environment have a peak value at 10Hz which defines the target bandwidth. In order to reach this target bandwidth a new computer vision sensor is proposed. The sensor uses a cost-effective camera and a computer to run the computer vision algorithm. By decreasing the delay from 60ms to 10ms a control bandwidth of 7Hz, using PID, is obtained in this work. Since the target bandwidth is 10Hz time delay compensation is considered to improve the performance. By implementing a Filtered Smith Predictor the target bandwidth of 10Hz is reached. The maximum control bandwidth of the controller, 15Hz, was derived in order to inspect the limit of computer vision sensors in precision systems.

Future consumer products, medical devices and manufacturing processes can benefit from systems with a high number and a high density of individually controlled actuators that are flexible and use little energy, materials and space. These systems with a high count and high density of actuators can be addressed as distributed actuation systems. In nature these distributed actuation systems are already present in the form of organs, eukaryotic cells or body parts such as an elephant’s trunk. This kind of system could be useful for handling fragile materials, delivering drugs inside the human body or creating replacement organs. Creating distributed mechatronic systems using conventional components is difficult, as the rigid parts often lead to complex constructions. This thesis presents a new paradigm for distributed actuation systems: combining planar bending smart materials with the Japanese art of Kirigami. This is demonstrated with the creation of a novel actuator design and modelling approach.First a literature study is presented on methods that have been used to actuate Origami and Kirigami (O&K) structures. General information is provided on several smart materials that can be used for this purpose. The reported methods and materials are evaluated on their potential for distributed actuation. The literature shows that electro-mechanical smart materials can be used for the design of distributed actuator systems. It is shown that multiple, scalable actuators can be designed in one sheet and can be actuated locally. Literature reveals preliminary research on cutting soft electro-active polymer (EAP) Kirigami structures. These EAPs are suitable for the creation of multi-DOF, distributed actuators using O&K techniques. However, this far the investigation addresses only cm-sized structures that exhibit a bending behaviour and the potential of the O&K techniques on EAPs have not been studied. The second study investigates the concept of utilizing Kirigami techniques on ionic polymer metal composite (IPMC) materials to manufacture distributed actuators. Different cm-sized designs are described and realized that produce a large strain linear motion from the bending motion of IPMCs. The designs are experimentally validated. The results demonstrate that it is possible to etch and cut a multitude of actuation units into planar bending smart material transducers and that bending actuation can be used to realize translation.To facilitate design and optimization of these IPMC Kirigami structures, a model is needed that predicts the electro-mechanical behaviour and is easy to implement. Existing models are not suitable as they will result in complex and elaborate model constructions when more advanced structures have to be implemented. This thesis presents a practical electrical model in Comsol Multiphysics. The electrical parameters of an IPMC beam are identified. Identified properties include the surface conductivity, through material conductivity and permittivity. The electrical models are validated by comparing the simulations with a time-domain experiment with a sinusoidal input signal of 1V at 1Hz. The results show that the models can be used to describe the macroscopic electrical behavior and can be further used in analysing more complex structures ones the mechanical part of the Comsol model is also completed.

The 3D-digitisation of precious cultural heritage artifacts is highly important for historical preservation purposes. Doing so can help mitigate against events such as tourism damage, natural disasters, and war. It also enables access to three-dimensional data for researchers of all disciplines all around the globe to study these artifacts at the same time. Furthermore, future generations can benefit from an online database of archaeological artifacts for educational purposes. Several high-end solutions are available. However, the cost to purchase or leasing can be too substantial for heritage institutions that often run on small budgets. Therefore, there is a need for cost-effective solutions to create high-quality 3D-images of archaeological artifacts. This thesis focuses on the 3D-imaging of small archaeological artifacts. When creating 3D-images of the artifacts, it is important to capture the texture details and preserve color information correctly. An extensive literature study was done on the existing 3D-imaging technologies and systems. It was concluded that photogrammetry is the most suitable technology available to create 3D-images of small archaeological artifacts. Photogrammetric systems have been studied for their ability to create high-quality 3D-images. Literature states that the quality of the 3D-images created with photogrammetric 3D-imaging systems suffers from a small depth of field. By the nature of optics, this small depth of field occurs when photographing an object from a close distance. This thesis provides the design and validation of a cost-effective photogrammetric 3D-imaging system for small archaeological artifacts. This system is optimized for the depth of field and is able to successfully create high-quality 3D-images with highly detailed textures and color information. This design overcomes the small depth of field limitations by implementing focus stacking. The system's most intensive task, the acquisition of photographs, has been automated, and a working compact system has been created.

This thesis is centred around the problem that heart failures become more common when other dis-eases could be treated better. Although surgery could fix the immediate effects of heart failures, therecovery after the surgery is hindered by the heart not being able to pump enough blood. There aresolutions available but they are not implemented due doing more harm then good to the heart. Thisthesis will look into a way to aid the recovering heart by applying a compressional force to the outsideof the heart. Previous attempts on fixing this problem could not follow the motion of the heart closeenough due to the lack of actuation resolution, i.e. the local differentiation of the actuation applied tothe heart. This caused damage to the heart muscle, which in the end causes death due to too littleblood flow.Due to lack of actuation resolution of the previous solutions, the focus of this thesis will be on the dis-tribution of the actuation and not the actuation to the heart itself. A baseline for the requirements wasneeded to make an informed decision about the different solutions to distribute the actuation. This wasdone using a MatLab script. This gave the actuation characteristics of a compression of 20 percent witha pressure of 20 [kPa] when a compression jacket of 5 [mm] thickness around the heart is used. Therelative high compression together with the pressure directed the solution for such an actuator towardsfluids.Common fluid actuators that would have a high local differentiation in actuation require lots of pumpsor lots of valves, both of these options have as a downside that they take up to much space. That iswhere smart fluids have an advantage by decreasing the size of a pump or a valve by including thefluid in the active volume. Two of these smart fluids that seem promising are; Ferrofluids and magnetorheological fluids. Ferrofluids are activated by a magnetic field and will cause a change in internalpressure similar to how gravity affects internal pressure in a fluid. The only difference is that it couldbe about four to five orders of magnitude stronger over small distances of about a tenth of a millimetre.The magneto rheological fluid changes its viscosity in the direction perpendicular to the magnetic fieldwith the change being related to the strength of the applied field.The thesis will discuss the use of Ferrofluids as an active fluid in a pump, and magneto rheologicalfluids, MRF, as the active fluid in a valve. Ferrofluids are not feasible to be used as individual unitsas they barely meet the requirements of 20 [kPa] of pressure with the flow rate needed to actuate thejacket, without taking the fluidic losses of such a jacket into account. Whereas the MRF based valvecould achieve a pressure difference of 20 [kPa] over the valve, without being of the limits of the op-erational value of the fluid. This is enough to have both a fully opened valve and a closed one usingthe pressure needed from the requirements. Therefor the thesis recommends the further research intoimplementing a full actuation system for a heart assist device using valves based on MRF.

Reset control is a "simple" nonlinear control strategy that has the potential of being widely adopted and improving the performance of systems traditionally controlled with PIDs. Lack of suitable methods for proving stability, that are in line with the current industrial practice, hampers the wider acceptance of reset control. In this thesis, novel sufficient conditions for stability of reset control systems, that can be evaluated using measured frequency response function of a system to be controlled, are derived using the hybrid passivity and finite-gain framework. A method for analysing the hybrid passivity and finite-gain parameters of reset systems, that can be extended to other classes of nonlinear systems, is developed. Additionally, a variant of the “Constant in Gain Lead in Phase” reset element, that facilitates the use of the proposed method for the stability analysis, is introduced. Stability of several precision positioning systems with reset controllers, designed for different objectives, is studied to demonstrate the applicability of the proposed hybrid passivity and finite-gain approach for the stability analysis of reset control systems. Guidelines for design of reset systems such that their stability can be concluded using the hybrid passivity and finite gain method are shown. This thesis presents a new view on the stability of reset systems and addresses the need for frequency-domain tools for stability analysis of nonlinear control systems in precision mechatronics applications.

High Tech industry is looking to push the bounds of what is possible, this requires machines that run with ever increasing speed and precision for longer amount of time under progressively more hostile environments. These requirements necessitate the use of compliant mechanisms/flexures instead of traditional rigid body counterparts. However, as these flexures are pushed to operate at ever higher speeds, high frequency modes affect precision and hence require better damping. Currently active damping relies on a single or small amount of actuators which makes their placement for multimode damping inefficient. To this end, the MetaMech project was created which aims to combine the disciplines of mechatronics and metamaterials to create flexures with integrated cells housing sensors, active and passive dampers in optimal positions and orientations. This will enable more efficient placement and orientation of dampers, reducing the force and thus the size and weight needed to damp the system. This thesis takes the first step in this direction and is concerned with developing the first prototype demonstrator of a metamaterial flexure with integrated damping using currently available technology. The presentation will cover the design, Finite Element Analysis and practical tests of a hexagonal patterned metamaterial flexure with integrated piezo patches. It also presents the design and finite element analysis of a more advanced hexagonal cell able to exert force in three different directions. The results provide proof of concept for the MetaMech project with insights for future work.

PID is the most popular controller in the industry. PID controllers are linear, and thus have fundamental limitations, such that certain performance criteria cannot be achieved. To overcome these limitations, nonlinear reset control can be used. Reset control can achieve less overshoot and a faster response time than linear controllers. However, the resetting mechanism has a jump function which causes jumps in the control input, which can result in limit cycles. Linear filters and controllers are designed in the industry using loop shaping, which is done in the frequency domain. In this study it is investigated how to analyse reset systems in the frequency domain. A reset system is nonlinear, so transfer functions needs to be approximated by describing functions. The sinusoidal input describing function considers only the first harmonic of the output and therefore does not capture all the dynamics of the element. The effects of the higher order harmonics are important in precision systems, since unwanted dynamics should not be excited nor should performance be affected. In this thesis, the higher order sinusoidal input describing functions (HOSIDF) are derived analytically. The HOSIDF shows the magnitude and phase response per harmonic, such that stability and performance analysis can be improved. Because the HOSIDF shows multiple responses, it is not trivial how to do loop shaping. The information from the HOSIDF is combined, creating a combined magnitude and combined phase response. It is seen that the combined magnitude looks promising, but the combined phase has jumps. It is concluded that the combined magnitude and combined phase are not mature enough to rely on during loop shaping and further work in this direction is required.

Stringent control demands from the high-tech mechatronics industry have warranted the need to explore potentially advantageous non-linear controllers. Variable Fractional Order (VFO) calculus provides one such avenue to build non-linear PID-like controllers. VFO calculus is the generalization of integer order differentiation and integration, where, in addition to the possibility of orders being real or even complex, the orders can vary as a function of a variable like time, temperature, etc. However, in this nascent field of VFO control, the focus has mainly been on controller tuning by time domain optimization of the performance for certain specific trajectories or cost functions. On the other hand, Frequency domain tools allow for analysis and tuning of controllers for performance over a wide range of exogenous inputs. For smooth adoption into industry, it is important to develop a frequency domain framework for working with VFO control. Describing function (DF) analysis is a method to obtain an approximate Frequency Response Function (FRF)-like function for non-linear systems. In this thesis, DF analysis is used for developing VFO PID controllers in the frequency domain from an industry compatibility point of view and the closed loop performance of these controllers in controlling a precision positioning stage is examined.

As the age of industry 4.0 evolves expeditiously, the demand for improved performance in the high-tech industry is rapidly increasing. Industries such as the semiconductor, optical, and metrology have a higher standard in regards of precision to enhance throughput rates and reduce production times between its various stages. The complex machines operating in such conditions are often exposed to structural or ambient vibrations, which pose a challenge to throughput rates. Hence it is a primary need to isolate the system from these vibrations by quickly damping them before it hampers the system process. In this thesis, a novel approach to active vibration isolation using skyhook damping is undertaken by introducing a reset-based bandpass filter. This filter is used to achieve finite-time vibration isolation for a damped metrology frame, and its development is inspired by the success of switch-based control in active isolation. The effectiveness of the filter is numerically tested for multiple types of vibration disturbances for improved transient damping characteristics, These findings are compared to a linear counterpart of the filter, demonstrating the benefit of applying reset control for improving transient performance.

To achieve high motion accuracy and repeatability for a variable reluctance tunable magnet actuator that uses linear controllers, this article proposes a novel actuator design that has a linearized force-flux relation. Prior designed variable reluctance tunable magnet actuators use a C-shaped actuator that has a quadratic relation between the force and the flux. By using lumped parameter models, an Hybrid Tunable Magnet Actuator design based on biased fluxes is developed. The linear behaviour of this design is proven by a finite element analysis. The force-flux relation is piecewise linear for different positions depending on the direction of the flux. Within a position range of ± 500 µm and a force range of ± 20 N, the error of a linear fit is in the order of 0.08 N. With an experimental setup the linear relation is also proven with an error of 0.03 N. Comparing the designed tunable magnet actuator with an hybrid reluctance actuator shows that the tunable magnet actuator is more efficient for quasi-static forces that are constant for time periods longer than 1.4 s.