Third–Generation Pleated Pneumatic Artificial Muscles for Robotic Applications: Development and Comparison with McKibben Muscle

This paper introduces the third generation of Pleated Pneumatic Artificial Muscles (PPAM), which has been developed to simplify the production over the first and second prototype. This type of artificial muscle was developed to overcome dry friction and material deformation, which is present in the widely used McKibben muscle. The essence of the PPAM is its pleated membrane structure which enables the muscle to work at low pressures and at large contractions. In order to validate the new PPAM generation, it has been compared with the mathematical model and the previous generation. The new production process and the use of new materials introduce improvements such as 55% reduction in the actuator’s weight, a higher reliability, a 75% reduction in the production time and PPAMs can now be produced in all sizes from 4 to 50?cm. This opens the possibility to commercialize this type of muscles so others can implement it. Furthermore, a comparison with experiments between PPAM and Festo McKibben muscles is discussed. Small PPAMs present similar force ranges and larger contractions than commercially available McKibben-like muscles. The use of series arrangements of PPAMs allows for large strokes and relatively small diameters at the same time and, since PPAM 3.0 is much more lightweight than the commong McKibben models made by Festo, it presents better force-to-mass and energy to mass ratios than Festo models.     

Deodorization optimization of Camelina sativa oil: Oxidative and sensory studies

Camelina sativa oil (CO) is characterized by a high content (up to 40 wt %) of essential α‐linolenic acid and characteristic odour and flavour. Deodorization of highly unsaturated oils requires great attention as the refining process involves thermal treatment which affects oil integrity. In the present study RSM and principal component analysis (PCA) were used to optimize bench‐scale deodorization of CO. Mathematical models were generated through multiple regressions with backward elimination, describing the effects of process parameters (temperature, steam flow, time) on oil quality indicators [peroxide value (PV), p‐anisidine value (p‐AV), γ‐tocopherol (γ‐T) and oxidative stability (OS)]. Additionally, sensory evaluation was performed. RSM analysis showed a significant effect of deodorization temperature and to a lesser extent, deodorization steam flow and time on removal of oxidative compounds, flavour and odour. PCA of chemical and sensory results showed that deodorization temperature affected the sensory properties in the samples. The best conditions for removing undesirable flavour and odour were achieved by using a deodorization temperature of 195–210°C.     

Optimal replacement policies for dairy cows based on daily yield measurements

Markov decision processes (MDP) with finite state and action space have often been used to model sequential decision making over time in dairy herds. However, the length of each stage has been at least 1 mo, resulting in models that do not support decisions on a daily basis. The present paper describes the first step of developing an MDP model that can be integrated into a modern herd management system. A hierarchical MDP was formulated for the dairy cow replacement problem with stage lengths of 1 d. It can be used to assist the farmer in replacement decisions on a daily basis and is based on daily milk yield measurements that are available in modern milking systems. Bayesian updating was used to predict the performance of each cow in the herd and economic decisions were based on the prediction. Moreover, parameters in the model were estimated using data records of the specific herd under consideration. This includes herd-specific lactation curves.     

Measuring the exhaled breath of a manikin and human subjects

Due to scarcity of accurate information and available data of actual human breathing, this investigation focuses on characterizing the breathing dynamic process based on the measurement of healthy human subjects. The similarities and differences between one breathing thermal manikin and the human subjects, including geometry and breathing functions, were thoroughly studied. As expected, actual human breathing is more complicated than that of the manikin in terms of airflow fluctuations, individual differences, and exhaled flow directions. The simplification of manikin mouth structure could result in overestimated exhaled velocity and contaminant concentration. Furthermore, actual human breathing appears to be relatively stable and reproducible for an individual person in several conditions and is also accompanied by some uncertainties simultaneously. The averaged values are used to analyze the overall characteristics of actual human breathing. There are different characteristics of the exhaled breath between male and female subjects with or without wearing a nose clip. The experimental results obtained from the measurement of human subjects may be helpful for manikin specification or validation and accuracy assessment of CFD simulations.     

Novel tubing microreactor for monitoring chemical reactions

There is an expanding interest in small-scale methods to evaluate catalysts and chemical reactions at a variety of conditions, ranging up to 6.9 MPa (1000 psig) and 300 degrees C. Multiwell parallel batch techniques are most commonly applied in high-throughput screening systems. In contrast, we describe here a rapid, serial, highly controllable method based on LC-type steel tubing rated for high pressures. The tube, containing a variety of flowing ingredients, such as carrier solvents, catalyst formulations, and reactants, is self-heated ohmically using electrical current from a power supply monitored and regulated with a precision of 0.01%. An array of voltage taps arranged along its length serves to sense the real-time temperature profile of the tube. Reactions are seen as temperature pulses progressing through the reactor, in zones of 200 microL each, and tracked with a temperature precision of 0.1 degrees C. A unique pressure controller was devised to maintain constant reactor pressures despite effluent viscosity fluctuations due to polymerization. Several chemical reaction systems have been characterized to date, including decomposition reactions of di-tert-butyl peroxide, polymerizations of styrene, formation of polyethylene from ethylene, and copolymerization of ethylene with 1-octene. For ethylene polymerization, the amount of mass of polymer formed is proportional to the responses observed.     

Surround video: a multihead camera approach

We describe algorithms for creating, storing and viewing high-resolution immersive surround videos. Given a set of unit cameras designed to be almost aligned at a common nodal point, we first present a versatile process for stitching seamlessly synchronized streams of videos into a single surround video corresponding to the video of the multihead camera. We devise a general registration process onto raymaps based on minimizing a tailored objective function. We review and introduce new raymaps with good sampling properties. We then give implementation details on the surround video viewer and present experimental results on both real-world acquired and computer-graphics rendered full surround videos. We conclude by mentioning potential applications and discuss ongoing related activities. Video supplements: http://www.csl.sony.co.jp/person/nielsen     

Demonstration of multi-core photonic crystal fibre in an optical interconnect

A novel microstructured fibre has been created for use in an optical interconnection system. The fibre has low crosstalk with a high density of cores corresponding to 1150 channels/mm/sup 2/. A repeating pseudorandom binary sequence has been used to demonstrate a four-channel transmit/receive system using vertical cavity surface emitting lasers as both emitters and detectors.     

Output stabilization and maneuver regulation: A geometric approach

This paper investigates maneuver regulation for single-input control-affine systems from a geometric perspective. The maneuver regulation problem is converted to output stabilization and necessary and sufficient conditions are provided to solve the latter problem by feedback linearizing the dynamics transverse to a suitable embedded submanifold of the state space. When specialized to the linear time invariant setting, this work recovers well-known results on output stabilization.     

On the Expressive Power of Temporal Concurrent Constraint Programming Languages: (invited talk)

The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages differing in their way of expressing infinite behavior have been proposed in the literature. In this work we study the expressive power of some of these languages. In particular, we show that: (1) recursive procedures with parameters can be encoded into parameterless recursive procedures with dynamic scoping, and viceversa. (2) replication can be encoded into parameterless recursive procedures with static scoping, and viceversa. (3) the languages from (1) are strictly more expressive than the languages from (2). Furthermore, we show that behavioral equivalence is undecidable for the languages from (1), but decidable for the languages from (2). The undecidability result holds even if the process variables take values from a fixed finite domain.(Joint work with Mogens Nielsen and Frank D. Valencia)     

Myocardial rupture during exercise ECG

We report a case of heart rupture in connection with a stress test performed nine days after an otherwise uncomplicated myocardial infarction. The Danish Association of Cardiologists recommend stress testing 5-20 days after myocardial infarction. We question whether this timing is appropriate considering the vulnerability of the myocardium at that time.