Proportional control

About: Proportional control is a research topic. Over the lifetime, 3756 publications have been published within this topic receiving 49050 citations.

Flow control system for spray applications

Abstract: A spray control system for applying a coating composition to an object. The control system includes an applicator, flow control valve, flow meter, and an electronic controller connected to the valve and flow meter. The controller regulates the flow of coating composition to maintain it at a user-specified setpoint. The controller includes a learn mode in which it learns the proper valve setting for a particular setpoint and stores a valve control signal that is later used at the start of a spray application to initially set the valve at the proper position. Then, once the flow of material begins, the controller uses either incremental or proportional control, or both, to maintain the flow at the specified setpoint. When learning a setpoint, the controller also stores the current values of a number of user-specified process parameters, such as ambient air temperature and the coating composition source pressure. These stored parameter values are then monitored during the spray application and an alarm notification is provided if they drift outside of a window about their stored values. The controller is configured to adapt to changing environmental and operational conditions by re-learning the proper valve setting for a particular setpoint each time the flow sufficiently stabilizes at the setpoint. Circuitry is also disclosed for use in connection with the flow meter to quickly determine the flow rate at the commencement of material flow and to provide fast updating of a conventional digital readout of flow rate.

Digital controllers for VTOL aircraft

Abstract: Using linear-optimal estimation and control techniques, digitaladaptive daptive control laws have been designed for a tandem-rocopteror heliopter which is equipped for fully automatic flight in terminal area operations. Two distinct discrete-time control laws are designed to interface with velocity-command and attitude-command guidance logic, and each incorporates proportional-integral compensation for nonzero-set-point regulation, as well as reduced-order Kalman filters for sensor blending and noise rejection. Adaptation to flight condition is achieved with a novel gain-scheduling method based on correlation and regression analysis. The linear-optimal design approach is found to be a valuable tool in the development of practical multivariable control laws for vehicles which evidence significant coupling and insufficient natural stability.

Nonlinear PD Synchronized Control for Parallel Manipulators

Abstract: A simple synchronized control algorithm is proposed, by incorporating cross-coupling technology into a common PD control architecture, for control of parallel manipulators. A saturated proportional (S-P) control and a linear proportional derivative (PD) control plus gravity force compensation is implemented for synchronization and position control, respectively. The proposed control law is easy to implement and is able to stabilize motion of each actuator while synchronizing all actuators’ motions, so that differential position errors amongst actuators converge to zero. It is shown that the proposed method guarantees global asymptotical stability of the closed-loop system. Experiments performed on a three-DOF parallel manipulator demonstrate the effectiveness of the proposed approach.

Development and experimental characterization of a pneumatic valve actuated by a dielectric elastomer membrane

Abstract: Due to their many features including lightweight and low energy consumption, dielectric elastomer (DE) membrane actuators are of interest for a number of industrial applications, such as pumping systems or valve control units. In particular, the use of DEs in valve control units offers advantages over traditional solenoid valves, including lower power requirements and relative simplicity in achieving proportional control. Additionally, DEs generate low thermal dissipation and are capable of virtually silent operation. The contribution of this work is the development of a new valve system based on a circular DE membrane pre-loaded with a linear spring. The valve is designed for pressurized air and operates by actuating a lever mechanism that opens and closes an outlet port. After presenting the operating principle and system design, several experiments are presented to compare actuator force, stroke, and dissipated energy for several pressure differentials and associated volume flows. It is observed that the DE-driven valve achieves a performance similar to a solenoid-based valve, while requiring a significantly lower amount of input energy. In addition, it is shown that DE-membrane valves can be controlled proportionally by simply adjusting the actuator voltage.