EXAMPLES OF CONTROL-SYSTEM APPLICATIONS :
Applications of control systems have significantly increased through advances in computer technology and development of new materials, which provide unique opportunities for highly efficient actuation and sensing, thereby reducing energy losses and environmental impacts.
State-of-the-art actuators and sensors may be implemented in virtually any system, including :-
Biological-Propulsion;
Locomotion;
Robotics;
Material-handling;
Biomedical,
Surgical,
Endoscopic;
Aeronautics;
Marine;
Defense Industry;
Intelligent Transportation Systems
The automobile and its evolution in the past two centuries is arguably the most transformative invention of man. Over the years, many innovations have made cars faster, stronger, and aesthetically appealing. We have grown to desire cars that are “intelligent” and provide maximum levels of comfort, safety, and fuel efficiency.
Examples of intelligent systems in cars include:
climate control, cruise control, antilock brake systems (ABSs), active suspensions that reduce vehicle vibration over rough terrain, air springs that self-level the vehicle in high-G turns (in addition to providing a better ride), integrated vehicle dynamics that provide yaw control when the vehicle is either over- or understeering (by selectively activating the brakes to regain vehicle control), traction control systems to prevent spinning of wheels during acceleration, and active sway bars to provide “controlled” rolling of the vehicle.
The following are a few examples:
Drive-by-Wire and Driver-Assist Systems
The new generations of intelligent vehicles are able to understand the driving environment, know their whereabouts, monitor their health, understand the road signs, and monitor driver performance, even overriding drivers to avoid catastrophic accidents. These tasks require significant overhaul of past designs. Drive-by-wire technology is replacing the traditional mechanical and hydraulic systems with electronics and control systems, using electromechanical actuators and human–machine interfaces such as pedal and steering feel emulators—otherwise known as haptic systems.
Hence, the traditional components—such as the steering column, intermediate shafts, pumps, hoses, fluids, belts, coolers, brake boosters, and master cylinders—are eliminated from the vehicle. Haptic interfaces can offer adequate transparency to the driver while maintaining safety and stability of the system.
Removing the bulky mechanical steering wheel column and the rest of the steering system has clear advantages in terms of mass reduction and safety in modern vehicles, along with improved ergonomics as a result of creating more driver space. Replacing the steering wheel with a haptic device that the driver controls through the sense of touch would be useful in this regard.
The haptic device would produce the same sense to the driver as the mechanical steering wheel but with improvements in cost, safety, and fuel consumption as a result of eliminating the bulky mechanical system. Driver-assist systems help drivers avoid or mitigate an accident by sensing the nature and significance of the danger. Depending on the significance and timing of the threat, these on-board safety systems will initially alert the driver as early as possible to an impending danger.
Then, it will actively assist or, ultimately, intervene in order to avert the accident or mitigate its consequences. Provisions for automatic override features, when the driver loses control due to fatigue or lack of attention, will be an important part of the system. In such systems, the so-called advanced vehicle control
System monitors the longitudinal and lateral control, and by interacting with a central management unit, it will be ready to take control of the vehicle whenever the need arises. The system can be readily integrated with sensor networks that monitor every aspect of the conditions on the road and are prepared to take appropriate action in a safe manner.
Integration and Utilization of Advanced Hybrid Powertrains
Hybrid technologies offer improved fuel consumption while enhancing driving experience. Utilizing new energy storage and conversion technologies and integrating them with powertrains are prime objectives in hybrid technologies.
Such technologies must be compatible with combustion engine platforms and must enhance, rather than compromise, vehicle function. Sample applications include plug-in hybrid technology, which would enhance the vehicle cruising distance based on using battery power alone, and utilizing fuel cells, energy harvesting(e.g., by converting the vibration energy in the suspension or the energy in the brakes into electrical energy) or sustainable energy resources, such as solar and wind power, to charge the batteries.
The smart plug-in vehicle can be a part of an integrated smart home and grid energy system of the future, which would utilize smart energy metering devices for optimal use of grid energy by avoiding peak energy consumption hours.
High-Performance Real-Time Control, Health Monitoring, and Diagnosis
Modern vehicles utilize an increasing number of sensors, actuators, and networked embedded computers. The need for high-performance computing would increase with the introduction of such revolutionary features as drive by-wire systems into modern vehicles.
The tremendous computational burden of processing sensory data into appropriate control and monitoring signals and diagnostic information creates challenges in the design of embedded computing technology. Toward this end, a related challenge is to incorporate sophisticated computational techniques that control, monitor, and diagnose complex automotive systems while meeting requirements such as low power consumption and cost-effectiveness.
Steering Control of an Automobile
Consider the steering control of an automobile. The direction of the two front wheels can be regarded as the controlled variable, or the output, y; the direction of the steering wheel is the actuating signal, or the input, u. The control system, or process in this case, is composed of the steering mechanism and the dynamics of the entire automobile.
Idle-Speed Control of an Automobile
As another example of a control system, we consider the idle-speed control of an automobile engine. The objective of such a control system is to maintain the engine idle speed at a relatively low value (for fuel economy) regardless of the applied engine loads (e.g., transmission, power steering, air conditioning).
Without the idle-speed control, any sudden engine-load application would cause a drop in engine speed that might cause the engine to stall.
Thus the main objectives of the idle-speed control system are
(1) to eliminate or minimize the speed droop when engine loading is applied
(2) to maintain the engine idle speed at a desired value.
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