Selected Control Algorithm Research Articles

Influence de différentes structures de commande sur le compromis temps/vibration – Application à une machine UGV

While improving the dynamical performance of a flexible motion control system, additional stresses are generated which induce undesirable vibrations. The design of adequate control algorithms makes it possible to enhance the overall behaviour of the machine while limiting its deformation modes vibrations. This paper presents a comparative study of the influence of different control algorithms on the trade-off between the cycle time and the amplitude of the residual vibrations, which have been applied to a Cartesian robot. While this selection of control algorithms is not exhaustive, these can all easily be implemented in current industrial systems. Each selected control algorithm is analysed along with experimental validations.

A Semi-active Oleodynamic Damper for Earthquake Control. Part 2: Evaluation of Performance through Shaking Table Tests

Sine sweep and earthquake excitation tests have been performed on a one-story spatial steel frame building equipped with two identical semi-active assemblies described and fully characterized in a companion paper. The tests allowed identifying and validating simple mathematical models of the building in its passive configurations as well as in semi-active operation according to an energy storing and suddenly dissipating algorithm. In order to eliminate or at least attenuate the detrimental effects of control delays due to adopted software, electronic apparatus and mechanical inertia of variable dampers' moving parts, a simple ‘sine-fit’ prediction method was conceived, evaluated and adopted in subsequent tests. It is shown that, with adequate anticipation of device operation, the selected control algorithm produces a satisfactory reduction of building response compared to that obtained in passive configurations, with overall system efficiency practically independent of the earthquake input and related only to the properties of the semi-active assembly.

Development of a daylight responsive dimming system and preliminary evaluation of system performance

In order to make a daylight responsive dimming system itself more flexible and reliable in both control method and system operation, a new system controlled by a computer software program has been developed. The light output from the dimmed luminaires is determined by the selected control algorithm, or is manually controlled in the computer software program. In this paper, the components of such a system are described, and the quantitative aspect of system performance has been evaluated. The results show accuracy and reliability on system performance. The workplane illuminance is maintained relatively close to the target level, and 30–70% of total lighting energy can be saved accordingly.

Automatic volume control system for compensation of volume difference between TV channels

The sound levels of TV channels vary greatly according to modulation and demodulation rates. When the television channel or input mode is changed, users have to adjust the volume in order to obtain a proper level of sound. In this paper, an automatic volume control system is proposed to compensate for the volume difference which occurs with channel changing. A simple power estimation based on the symmetry property of sound and a selective volume control algorithm using a 3-step compensation are presented. The proposed system is designed using consumer ICs for easy implementation to current audio media. In addition, a filter is used to revise the system function in order to model the frequency response of the designed system upon that of a human at a normal hearing level. For the experimental results in a TV set, it is shown that the volume fluctuation is considerably reduced.

On the optimal design of an automotive lateral controller

An optimization approach is used to design a velocity-adaptive, lateral controller to meet requirements pertaining to lateral-position, tracking accuracy, robustness, and ride comfort. The resulting controller, which is nonlinear with velocity, requires full-state feedback and thus an observer is included. The observer/controller compensator was implemented using a 16-bit microcomputer and evaluated in a laboratory study wherein vehicle lateral dynamics were simulated on an analog computer. Excellent lateral control, i.e. close tracking (with absolute value of lateral-position error below 0.024 m in curve tracking), good sensitivity to disturbance forces, and probable ride comfort resulted. The selected control algorithm was realized using some 5% of the available computation time, thus allowing the microcomputer to be used for other control functions and vital-function monitoring. >

A Velocity-Adaptive, Microprocessor-Based, Vehicle Lateral Controller

A velocity-adaptive lateral controller was designed to meet requirements pertaining to lateral-position tracking accuracy, ride comfort, and an insensitivity to both changes in critical vehicle parameters and disturbance forces. This controller was implemented using a 16-bit microcomputer (which was based on an Intel 8086 microprocessor) and installed in a dual-mode test vehicle.The controller/vehicle combination was evaluated under field conditions at the Transportation Research Center of Ohio. A wire-follower configuration was employed to provide both a lateral reference and a lateral position error (ΔSf). The vehicle was automatically steered on straight sections of roadway at speeds up to 35.8 m/s, and small-radius (100-m) curves were traversed at speeds up to 17.9 m/s. Excellent lateral control -- close tracking (|ΔSf|<0.07m on curved sections), a comfortable ride (aRMS<0.2m/s2) and a good insensitivity to disturbance forces -- resulted.The selected control algorithm, which involved an inverse compensation stage for velocity-independent performance and a lead/lag stage for both good tracking and ride comfort, was realized using some 10 percent of the available computation time. Thus, the microcomputer could also be employed for such tasks as vital function monitoring (e.g., oil pressure, alternator output and engine temperature), and serve as a source of intelligence on-board the vehicle. The latter could be especially important in reducing the response time to various emergencies.

Evaluation of exogenous insulin homoeostasis by the artificial pancreas in insulin-dependent diabetes.

With the artificial pancreas used by the authors, insulin was delivered through a venous infusion and the rate of delivery was adjusted according to data provided by a continuous blood glucose monitor. After different trials we selected control algorithms integrating two parameters: instantaneous blood glucose concentration and increasing or decreasing patterns of blood glucose. A constant basal insulin infusion rate was added and improved the control of glycaemic excursions. Different parameters concerning exogenous insulin homoeostasis were determined. The delay to reach an insulin effect was 18+/-2 min and was shortened by a priming-dose at the beginning of the infusion. The insulin effect remained for 28+/-2 min after the infusion had been stopped, but differences were noted in the morning (21+/-2 min), in the afternoon (32+/-2 min) and during the night (25+/-3 min). Insulin needs were evaluated during meals. Related to the amount of carbohydrates, the doses fell from 0.53 units/hr/g of carbohydrate for breakfast to 0.15 for dinner. From these data, it appears that the efficiency of exogenous insulin exhibits a circadian rhythm.