Control Systems

Distributed Parameter Systems are infinite dimensional systems generally described by partial differential equations. Designing controls for PDEs is a challenge since each type of PDE require different type of control design. Approximations of the PDE using numerical techniques are generally carried out in order to design controller but they have inherent spillover problem. DPS systems can be controlled using piezoelectric sensors and actuators and sensor/actuator resolution plays important role in accurate estimation of system state for better controllability. These problems have real-time value since most of the structures say, from aircrafts, spacecrafts to thin shells and ship hulls, are continuous systems.

Autonomous vehicles is one of the most exciting research areas today in the field of automobile engineering. Research in vehicle dynamics is one of the core areas of this fast emerging technology. Current research focuses on control of later and longitudinal dynamics of autonomous vehicles, and integration of both to complete the navigation problem. Such a vehicle can autonomously execute the path assigned to it accurately with little error in tracking the required system states of positions and velocities about the four degrees of freedom of interest namely, X, Y, Yaw and Roll.

Efficient energy management by optimizing the operating parameters and achieving platoon behavior from vehicles with decentralized control are other important applications of autonomous vehicles. Research in these applications focuses on designing optimization algorithms that can be customized for a given path, achieving string stability in vehicle platoons and devising efficient and robust communication strategy among the autonomous platoon vehicles.

Smart Material Actuated Morphing Wings:

The real-time change of shape of compliant structures to improve the efficiency of mechanisms is defined as morphing. With the advent of unmanned aerial vehicles (UAVs), there has been a renewed interest in shape morphing technology.

The current project on wing morphing delves on developing smart material actuated variable stiffness structures for shape morphing. Towards that, the integration of bi-stable laminates as compliant structural elements, different actuation strategies to attain local snap-through, and the possibility of using variable stiffness corrugated structural core for aerofoil morphing are being explored. The project combines the concepts of structural mechanics, aero-elasticity, computational fluid dynamics, and material science to design integrated, compliant systems. The objectives include:

1. Development of composite compliant structures taking advantage of compliance and bistability obtained from thermal buckling.

2. Understanding and quantifying the mechanics of variable stiffness structural element.

3. Development of Macro-fiber composite (MFC) and shape memory alloy (SMA) wire actuated systems.

4. Development of a control scheme taking into account all the complex aero-elastic interactions

Double corrugated variable camber (DCVC) design:

The need for energy efficient mechanical systems is one of the prime frontiers of engineering research .With the ever-increasing applications of air vehicles, morphing technology holds a key to optimise aircraft wings for the best possible performance without compromising fuel efficiency.

Aircraft wings are provided with high lift devices called trailing edge flaps that help in increasing lift generation by modifying wing camber. These devices as a downside, create a sharp turn in the wing surfaces which raises the drag and brings down aerodynamic efficiency. This surface discontinuity can be tackled using compliant structures to produce continuously controlled variable camber wings.

A double corrugated sheet arrangement as shown in the above figure is selected as a candidate design for a passive camber morphing wing and is named, Double Corrugated Variable Camber (DCVC) mechanism. The current work aims at the development and fabrication of this design in view of using it in an unmanned ariel vehicle (UAV), to enhance its performance in its various flight phases in an energy efficient manner.