Numerical Assessment of Seven Ventilation Systems for Social Residential Buildings based on Indoor Air Quality and Energy Consumption

This work presents a modelling approach for evaluating ventilation systems for their ability to provide good indoor air quality in dwellings. Infiltration and ventilation rates are defined by the conventional French 3CL-DPE standard. The case study is a two-bedroom apartment with a shared or separate kitchen and living room. Three natural ventilation options and four mechanical ventilation systems are compared with respect to exposure to PM2.5, NO2 and formaldehyde. Pollutant concentration levels are assessed in each room based on a scenario of daily occupancy, average annual outdoor concentrations and internal sources. The daily exposure of the occupants to the targeted substances allows the comparison of ventilation systems on the basis of the ULR-QAI index developed at LaSIE laboratory from La Rochelle University. For this case study, it results that controlled mechanical systems are much more efficient than natural ventilation systems, especially in the case of an open-plan kitchen.

Multi-domain optimization of the eigenstructure of controlled underactuated vibrating systems

The paper proposes a multi-domain approach to the optimization of the dynamic response of an underactuated vibrating linear system through eigenstructure assignment, by exploiting the concurrent design of the mechanical properties, the regulator and state observers. The approach relies on handling simultaneously mechanical design and controller synthesis in order to enlarge the set of the achievable performances. The underlying novel idea is that structural properties of controlled mechanical systems should be designed considering the presence of the controller through a concurrent approach: this can considerably improve the optimization possibilities. The method is, first, developed theoretically. Starting from the definition of the set of feasible system responses, defined through the feasible mode shapes, an original formulation of the optimality criterion is proposed to properly shape the allowable subspace through the optimal modification of the design variables. A proper choice of the modifications of the elastic and inertial parameters, indeed, changes the space of the allowable eigenvectors that can be achieved through active control and allows obtaining the desired performances. The problem is then solved through a rank-minimization with constraints on the design variables: a convex optimization problem is formulated through the “semidefinite embedding lemma” and the “trace heuristics”. Finally, experimental validation is provided through the assignment of a mode shape and of the related eigenfrequency to a cantilever beam controlled by a piezoelectric actuator, in order to obtain a region of the beam with negligible oscillations and the other one with large oscillations. The results prove the effectiveness of the proposed approach that outperforms active control and mechanical design when used alone.

Adaptive Hydraulic Drive of Manipulator

At present in manipulators the hydraulic drives with one degree of freedom are used. Such drive provides single-valued function of constraint between input and output links motion. However for overcoming of variable force of resistance it is necessary to use the variable transfer ratio between input and output links. The adjustable drive should contain the controlled gear box. Such drive contradicts the demand of minimization of weight and sizes of modules of the manipulator. Use of electronic control systems for force regulating leads to extreme complication of drives, decrease in their reliability, raise of cost of manufacturing and maintenance.Recently the adaptive self-controlled mechanical systems were appeared. By analogy to the adaptive mechanism the hydraulic adaptive mechanism which provides force self-regulation without a control system has been developed and the patent for invention was received.In paper the description and research of the adaptive hydraulic mechanism and creation of the manipulator module with the simplest compact hydraulic drive are adduced.

Novel Concepts and Criteria for Design Optimization of Controlled Mechanical Systems

Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.