Knowledge Integration

FINE392: Technology Art Studio" is an innovative course developed in collaboration with Engineering and Fine Arts at the University of Waterloo. The course is team-taught by faculty from Engineering and Fine Arts, and the curriculum includes formal sculptural concepts, collaboration, installation, usercentreed design, electricity and electronics, microprocessors, and technology art history. Engineering and Fine Arts students collaborate in interdisciplinary pairs on technology-mediated sculptural works over the duration of the course, culminating in a public exhibition at end of term. FINE392 and similar cross-disciplinary collaborative courses provide an environment conducive to creativity and transformative learning. The eventual goal of our research is to draw conclusions about how to best design and implement such courses in order to maximize the learning experience, leading to a course development model. Here, we discuss the results of a study conducted during the 2006 offering of the course to methodically examine qualitative indicators of transformative learning. Students were asked in a guided-question format to reflect each week on the course impact and the progress of their projects and groups. Analyzing the results, we have identified a progressive pattern in the learning process, leading up to transformative learning events.

Measuring the spatial and temporal characteristics of hand movement is a challenging task due to the large number of degrees of freedom (DOF) in the hand. This paper presents a multi-constrained inverse kinematics (IK) approach for hand motion estimation from motion capture data. The IK approach satisfies a set of prioritized motion and postural constraints for each hand joint and link. The high-priority constraint is fully satisfied, while the fulfilment of the lowpriority constraints is achieved as long as no conflict with the high-priority constraint exists. The proposed approach can aid marker-based motion capture technologies in accurately reconstructing discontinuities or erroneous marker trajectory segments resulting from occluded, missing, or flipped markers. The performance of the multi-constrained IK approach for the hand is tested for a full range of continuous hand motion.

The Laban Effort and Shape components provide a systematic tool for a compact and informative description of the dynamic qualities of movements. To enable the application of Laban notation in computational movement analysis, measurable physical correlates of Effort and Shape components need to be identified. Such physical correlates enable quantification of Effort and Shape components, which in turn facilitates computational analysis of affective movements. In this work, two existing approaches to quantification of Laban Effort components (Weight, Time, Space, and Flow) based on measurable movement features (position, velocity, acceleration, and jerk) are adapted for hand and arm movements, and a new approach for quantifying Shape Directional based on the average trajectory curvature is proposed. The results show a high correlation between Laban annotations provided by a certified movement analyst (CMA) and the quantified Effort Weight (81%), Time (77%) and Shape Directional (93%) for an affective hand and arm movement dataset.

Perception and generation of affective movements are essential for achieving the expressivity required for a fully engaging human-machine interaction. This paper develops a computational model for recognizing and generating affective hand movements for display on anthropomorphic and non-anthropomorphic structures. First, time-series features of these movements are aligned and converted to fixed-length vectors using piece-wise linear re-sampling. Next, a feature transformation best capable of discriminating between the affective movements is obtained using functional principal component analysis (FPCA). The resulting low-dimensional feature transformation is used for classification and regeneration. A dataset consisting of one movement type, closing and opening the hand, is considered for this study. Three different expressions, sadness, happiness and anger, were conveyed by a demonstrator through the same general movement. The performance of the de-A. Samadani ( ) · veloped model is evaluated objectively using leave-one-out cross validation and subjectively through a user study, where participants evaluated the regenerated affective movements as well as the original affective movements reproduced both on a human-like model and a non-anthropomorphic structure. The proposed approach achieves zero leave-one-out cross validation errors, on both the training and testing sets. No significant difference is observed between participants' evaluation of the regenerated movements as compared to the original movement, which confirms successful regeneration of the affective movement. Furthermore, a significant effect of structure on the perception of affective movements is observed.

This paper deals with the L 2 stability of a shape memory alloy (SMA) actuated position control system, based on a single SMA wire under constant axial load. It is shown that system stability can be guaranteed for a large class of controllers having certain dissipativity characteristics. In particular, the results can be used to show stability under approximated PID, PI and PD control. Experimental step responses are given for two di erent PI controllers. The rst controller guarantees a stable response, based on the work presented. While the second system displays superior performance and seems stable, it does not satisfy the stability criterion of the paper. This comparison underscores the conservative nature of the stability result.

Actuators made from so-called smart materials have been proposed in the literature, for use in shape control of various surfaces. At the lowest level, this shape control problem can be thought of as a distributed regulation problem. Because of the hysteresis nonlinearity present in these actuators, there are an infinite number of input values corresponding to a particular output regulation setpoint. One might then ask the question, not relevant to memory-less systems, whether there is some advantage to regulating about one of these states in particular. This work proposes, based on observations from the Preisach model, that for any desired output there is one state in particular at which the system has a better natural (open-loop) rejection of uniformly-distributed noise at its input. This proposition is tested in both simulation and experiment. The reachability of this so-called `neutral state' is discussed, as is the generation of an input to drive the system to the appropriat...

We discuss closed-loop control of hysteretic systems having Preisach representations. We apply dissipativity methods, the key component of which is the determination of an appropriate supply rate. The concept of cyclo-dissipation is used to identify a new supply rate for Preisach hystereses and dissipativity with respect to this supply rate is shown. The result is useful in the design of output feedback controllers, and complements a previous result using feedback of the output derivative. We consider the specific example of a shape memory alloy actuator and identify a class of controllers which provide stability of position feedback with current as the control variable. This demonstrates one way in which system dynamics that couple with hysteresis can be included in controller design.

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Actuators made from so-called smart materials have been proposed in the literature, for inclusion in mechatronic systems used in shape control of various surfaces. At the lowest level, this shape control problem can be thought of as a number of distributed regulation problems. Because of the hysteresis nonlinearity present in these actuators, there are an infinite number of system states corresponding to a particular output regulation set point. This adds complexity to the regulation design problem, and it was shown in past work that, unlike memoryless systems, using one of these states in particular resulted in better open-loop rejection of input noise. This result was shown in simulation only, for a shape memory alloy actuator. This paper furthers the investigation of the effect of initial state on output regulation, by showing the same result holds for piezoceramic actuators, and includes critical experimental confirmation using a piezoceramic stack actuator.

Shape memory alloys (SMA) provide exciting opportunities for scalable actuation systems. As SMA actuators are scaled down in size, cooling increases and bandwidth, one of the traditional drawbacks of larger-scale SMA actuators, improves. However, the inclusion of a bias element with which to cycle the SMA actuator becomes difficult at very small scales. One technique that has been applied to avoid the necessity of having to include a separate bias element is the use of local annealing to fabricate a monolithic device out of a single piece of non-annealed NiTi. The annealed portion exhibits the shape memory effect while the remainder acts as structural support and provides the bias force required for cycling. This approach suffers several limitations in both fabrication and design. Here, we present the evolution of this idea: the hybrid monolithic actuator. Using powder metallurgy (PM) techniques, a hybrid monolithic actuator is fabricated with areas of shape memory effect (SME) NiTi as well as areas of superelastic NiTi which act as restoring members. Bulk training is possible by constraining the monolithic component in an appropriate jig and subjecting the entire device to a heat treatment cycle, avoiding the difficulties of local annealing. Recoverable strains in the superelastic NiTi are comparable to those in the SME material, increasing capability for cyclic motion. A prototype PMfabricated bending actuator is demonstrated which achieves cyclic tip deflection of approximately 10% of its length during a heating/cooling cycle.

Shape Memory Alloys (SMAs) are well suited for use as linear actuators. In particular, NiTi wires as linear SMA actuators offer the advantages of light weight, a simple actuation mechanism and high force-to-weight ratio. An additional advantage is that the electrical resistance of the NiTi wires varies intrinsically as the material undergoes a phase change between martensite and austenite, and so can be used as a sensing element in controlling the actuator system. In the past, models of the resistance behaviour have been used with some success in controller design. These models are often simplified, assuming a linear change between austenite and martensite resistances. More complex models may include non-linear dependence on phase transformation, but most neglect to account for the impact of changes in temperature and stress. The focus of this work is the investigation of a more detailed electrical resistance model that accounts for these effects during Joule heating of NiTi wires. The model takes into account the effects of temperature, stress, and martensite phase fraction. Data obtained from controlled experimental trials using a 0.254mm diameter Flexinol wire is used to identify model parameters, and the model is simulated and validated experimentally. The eventual goal is to use the model for simulation during controller synthesis, and also incorporate it into online controllers. Hence, the inversion of the model and its application in controller design is also discussed.

To enable long term, engaging social humanmachine interaction, robots and other autonomous systems must be able to move beyond purely reactive interaction control strategies, and engage in shared-initiative interaction. In this paper, we describe an implementation of an interactive art sculpture which generates interactive behaviours using curiosity-based learning. Using its own internal motivation formulated as a curiosity drive, the system initiates interaction with and responds to human visitors, generating continuously evolving interactive behaviours. The proposed system was tested in a user study with a prototype interactive sculpture installation.

This paper deals with the identification and control of the macro drive ofa macro-micro positioning system with mechanical nonlinearities. The experimental system consists of a modified ink-jet printer. modeled as a sliding mass actuated by a D.e. motor. The linear dynamics are assumed separable from saturation and friction nonlinearities. Coulomb friction is approximated as a dead zone and linearized through its inverse, allowing for MLS identification of the remaining I i near dynamics. The dead-zone friction model is then tuned to accurately reflect experimental results, and a full nonlinear model is formed. The resulting model is used as a basis to design a controller. Copyright © 2()()", IFAC

Actuators made from so-called smart materials have been proposed in the literature, for use in shape control of various surfaces. At the lowest level, this shape control problem can be thought of as a number of distributed regulation problems. Because of the hysteresis non-linearity present in these actuators, there are an infinite number of input values corresponding to a particular output regulation setpoint. One might then ask the question, not relevant to memory-less systems, whether there is some advantage to regulating about one of these states in particular. This work begins to investigate the answer to this question, with the finding that for any given desired output, there is one state in particular at which the system has a better natural (open-loop) rejection of normally-distributed noise at its input.

Macro-micro systems allow high-resolution positioning over greater ranges of operation that would be achievable with precision positioning systems. Piezoceramic actuators have established themselves as the principle technology for commercial micro-positioning applications, and the trend in research is to push the limits of resolution down to the nanometer and sub-nanometer scales. Other smart materials offer the potential for lightweight, continuous actuation over small ranges, and hence may be useful in micro-positioning applications. This work focuses on the potential for SMA actuators to enable low-cost micro-positioning. Compared to piezos, SMA offer longer range and lower actuation voltages, enabling lower-cost drive electronics and removing the need for costly precision mechanical amplification stages. A prototype single-axis macro-micro positioning system is described, with a macro range of 200 mm and relative positioning precision of better than 5 5μm. The micro stage is dri...