Abstract
Real time parameter estimation of dynamic models operating in closed loop control is a crucial issue to implement industrial adaptive controllers. Parameter estimation must be seen as one of the key elements to solve a system identification problem, which involves also an experiment design, the selection of a model structure, and the model validation. This paper describes some approaches to compute the transfer function parameters of time-varying systems under closed loop control. To point the limitations and advantages of each method, with focus on robustness and quality of the model estimates, the techniques are applied to compute the parameters of a time varying discrete system, with known structure, under PI- Proportional-Integral control.

Abstract
In a general screening of some mining areas in SE Spain for wild and autochthonous plant species with the potential to accumulate zinc and lead, of which some classified as accumulators were able to accumulate large concentrations of metal ( > 1000 mg kg(-1)) dry matter. Several Mediterranean taxa showed moderately enhanced heavy-metal accumulation and tolerance, e.g. Piptathertan miliacetall (L.) Cosson, or Smilo grass. This could be considered a Pb hyperaccumulator, being most efficient at removing and accumulating Ph from contaminated soil, and also efficient in Zn extraction. When soils were polluted with both metals, accumulation of Ph was greater. Results indicated that concentration of metal in the plant was directly correlated with that of the soil, although the transfer factors for Ph and Zn were not high. Most plants remained healthy for 3 weeks after introduction of pollutants.

Abstract
The estimation of the harmonic content of an ADC output is fundamental to evaluate its suitability to perform according the requirements specified for an application. The use of the traditional frequency analysis leads to a large hardware overhead due to the amount of on-chip processing being involved, or to a large quantity of data to be transferred in case the processing is performed in a tester. This paper presents an algorithm capable of estimating the harmonics with similar accuracy but with the advantage of being more suitable for a BIST implementation, since it requires a reduced number of on-chip operations, and that only a small set of values has to be supplied outside the chip for further processing. It relies, on the fact that harmonics generated by an ADC are mathematical related with the polynomial coefficients of its transfer function. ADC offset and gain errors can also be measured.

Abstract

Abstract
This paper studies the dynamics of foot-ground interaction and the performance of integer and fractional order controllers in multi-legged locomotion systems. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, to compare the system performance, we formulate six performance measures of the walking robot namely, the mean absolute power, the mean power dispersion, the mean power lost in the joint actuators, the mean force of the interface body-legs per walking distance and the mean square error of the hip and foot trajectories. A set of model-based experiments reveals the influence of the different controller implementations in the proposed indices.

Abstract
This paper compares the performance of classical position PD algorithm with a cascade controller involving position and force feedback loops, for multi-legged locomotion systems and variable ground characteristics. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, we formulate several performance measures of the walking robot based on the robot and terrain dynamical properties and on the robot hip and foot trajectory errors. Several experiments reveal the performance of the different control architectures in the proposed indices.