Alejandro Ramirez-Serrano

Robust neural network control of a quadrotor helicopter

This paper proposes a new adaptive neural network control to stabilize a quadrotor helicopter against modeling error and considerable wind disturbance. The new method is compared to both deadzone and e-modification adaptive techniques and through simulation demonstrates a clear improvement in terms of achieving a desired attitude and reducing weight drift.

Understanding how children understand robots: Perceived animism in child-robot interaction

Centuries ago, the existence of life was explained by the presence of a soul (Tylor, 1871). Known as animism, this term was re-defined in the 1970s by Piaget as young childrens beliefs that inanimate objects are capable of actions and have life-like qualities. With the development of robots in the 21st century, researchers have begun examining whether animism is apparent in childrens impressions of robots. The purpose of this study was to use a model of knowledge structures, or schemata, to examine whether children attribute human qualities of cognition, affect, and behavior to a robot. An experiment was set up at a science center located in a major Western Canadian city, and visitors to the center were invited to participate. A total of 198 children ages 5-16 years (M=8.18 years) with an approximate even number of boys and girls were included. Children completed a semi-structured interview after observing a robot, a small 5 degree of freedom robot arm, perform a block stacking task. Answers to the nine questions about the robot were scored according to whether they referenced humanistic qualities. Results from frequency and content analyses suggest that a significant proportion of children ascribe cognitive, behavioral, and especially affective, characteristics to robots.

Adaptive fuzzy control for a quadrotor helicopter robust to wind buffeting

The nonlinear and open-loop unstable dynamics of a quadrotor helicopter makes a control system design non-trivial. However, even more difficulty lies in adapting to an uncertain dynamic model and unknown payloads while remaining robust to significant buffeting wind disturbances. Fuzzy-adaptive or neural-adaptive control offer possible solutions, exhibiting computational efficiency and adaptation to arbitrary nonlinearities. A common method for making these adaptive controls robust to disturbances, e-modification, is found to be unsuitable when applied to the quadrotor in simulation. The adaptive parameters tend to drift to large values in the presence of a sinusoidal disturbance. In this work, we propose a method that uses alternate adaptive parameters in the adaptation scheme. The proposed method successfully controls the quadrotor in simulation, with realistic control signals and computational effort. The adaptive parameter drift and control chatter present with e-modification both vanish. Moreover, performance improves dramatically in the presence of disturbances.

Customer-driven product design and evaluation method for collaborative design environments

Product concept generation and evaluation in a product development environment has been identified as the two major activities needed for obtaining an optimal design scheme. Product conceptual design is of critical importance in design through customer involvement for the systematic and simultaneous consideration on the impact of design decisions on manufacturing and assembly leads to repeated and excessive changes in design and processes. This paper introduces a novel knowledge support approach for the organization and ranking of design feature knowledge towards an integrated product model that incorporates a feature-based representation scheme targeted to evaluate the impact of design on subsequent activities in the conceptual design phase, taking into account the presence of design information and user preferences. An uncertain linguistic multi-attribute decision-making evaluation model is proposed and discussed for obtaining an optimal design scheme during the evaluation and selection of product design alternatives in conceptual design. The focus of this paper is on the development of a knowledge-intensive support design scheme and a comprehensive systematic fuzzy evaluation methodology for product conceptual design generation, evaluation, and selection. A case study and the corresponding scenario of knowledge support for design alternatives generation, evaluation and selection are provided for illustration.

Moore Automata for the Supervisory Control of Robotic Manufacturing Workcells

The potential of flexible-manufacturing workcells (FMCs) to produce a family of parts in many possible orders of operations and choices of different machines is advantageous. Despite intensive research on the theoretical control of discrete-event systems (DESs), however, current techniques can still only be used for the supervisory control of simple cells. In this paper, a novel modeling and control synthesis technique is presented for FMCs that allow part-routing flexibility. Our proposed methodology combines Extended Moore Automata (EMA) and Controlled-Automata theories to synthesize supervisors for such FMCs.

Automata-based modeling and control synthesis for manufacturing workcells with part-routing flexibility

The utilization of flexible manufacturing workcells (FMCs) to produce families of parts in many possible orders of operations and choices of different machines is advantageous. The modeling and control of such discrete-event systems (DESs) have generally been performed in a hierarchical structure. Despite intensive research on the theoretical control of DESs, however, current techniques such as controlled automata can still primarily be used for the supervisory control of simple cells. In the paper, a modeling and control synthesis technique is presented for FMCs that allow part-routing flexibility. The proposed methodology combines extended Moore automata (EMA) and controlled-automata theories to synthesize supervisors for such FMCs. EMA-based supervisors have the capability to read (receive) multiple pieces of information regarding the behavior of the FMC. Based on this information they can explicitly generate control commands issued to cell devices. In order to significantly reduce the state-space of EMA-based supervisors without affecting the behavior enforced on the (controlled) FMC, a minimization procedure is also outlined.

Modelling of Opposed Lateral and Longitudinal Tilting Dual-Fan Unmanned Aerial Vehicle

Abstract In this paper, first an overview and explanation of the Oblique Active Tilting (OAT) and Opposed Lateral Tilting (OLT) control concepts are presented. A complete dynamic model of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs) having lateral and longitudinal rotor tilting mechanism is developed using a Newton-Euler formulation for double axis OAT mechanism (dOAT). Then, a theoretical analysis of OAT vehicle control response and stability for pitch, roll and yaw motion is described and simulated using the derived dynamic model. The aim of the aspects presented in this paper is to fully enable the highly maneuverable characteristics of UAV possessing dOAT which renders them to navigate in highly confined environments by performing semi-acrobatic maneuvers in hover lateral and forward flight.

Adaptive distributed fetching and retrieval of goods by a swarm-bot

Swarm robotics is a rising paradigm which aims at designing new robot artifacts by extracting engineering guidelines from Nature. The work presented here shows the use of a particular swarm of robots called swarm-bot for carrying out distributed missions of fetching and retrieval of objects. To solve this task, a high level description plan defined in terms of behaviors is synthesized. A mission is divided in four different stages: searching for a target, calling for a swarm to aggregate as soon as one is found, jointly fetching it, and jointly retrieving it back. All robots used (s-bots) are assumed to know the same set of behaviors as well as the same behavioral plan for carrying out the task. Units are kept purely reactive, thus they do not keep any memory of their previous history. This allows to withstand changes in a highly dynamic environment. Coordination is achieved asynchronously by using light signals, whereas cooperation for the actual transportation is realized by using a force sensor located between the turret and the tracks of each s-bot. A swarm-bot, which is formed by a group of s-bots physically connected to their target, is capable of behaving during its homeward motion as if it were a single entity. Experiments show the high level of adaptability and resilience of a swarm-bot with respect to occasional possible failures of its members

A hybrid PC/PLC architecture for manufacturing-system control—theory and implementation

This paper presents a novel and generic PC/PLC-based software/hardware architecture for the control of flexible manufacturing workcells. The proposed implementation methodology is based on the utilization of any one of the available formal discrete-event-system control theories in conjunction with state-of-the-art industrial programmable-logic controllers (PLCs). The methodology has been illustrated to be a viable technique through its actual implementation in our laboratory using a robotic-workcell testbed. The specific control theory used is a combination of Extended Moore Automata and Ramadge-Wonham Automata that has been developed by our research group. The modular control software architecture has been developed for MS-Windows environments (running on one PC interfaced to the PLCs) and allows the use of different formal control theories as well as different commercial PLC hardware. The effective graphical user interface provides a transparent programming environment, where users are not expected to have a full knowledge of the formal control theory used.

An optimum design selection approach for product customization development

Consumer preferences and information on product choice behavior can be of significant value in the development processes of innovative products. In this paper, product customization evaluation and selection model is introduced to support imprecision inherent of qualitative inputs from customers and designers in the decision making process. Focusing on customer utility generation, an optimum design selection approach based on fuzzy set decision-making is proposed, where design attributes priority is identified from customer preferences using an analytical hierarchy process. A multi-attribute analysis diagram is developed to visualize the preference of each attribute from the expert’s group decision. Conjoint analysis is used in the product customization to focus on customer utility generation in terms of multiple criteria. The use of the decision-making method is illustrated with a case example that highlights the utility of the proposed method.