Proportional control

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

Control device for continuously variable transmission

Abstract: A control device for a continuously variable transmission performs a feedback control wherein an integral control gain and a proportional control gain of the feedback control are varied depending upon an operating position assumed by a shift actuator.

Model reference robust speed control for induction-motor drive with time delay based on neural network

Abstract: Proposes a novel model-reference robust speed control with a load torque estimator and feedforward compensation based on a neural network (NN) for induction motor drives with time delay. First, a two-layer neural network torque estimator (NNTE) is used to provide real-time identification for an unknown load torque disturbance. The backpropagation algorithm was used as the learning algorithm. In order to guarantee the system's convergence and to obtain faster NN learning ability, a Lyapunov function is also employed to find the bounds of the learning rate. Since the performance of the closed-loop controlled induction motor drive is influenced greatly by the presence of the inherent system dead-time during a wide range of operations, a dead-time compensator (DTC) and a model-reference-following controller (MRFC) using a NN proportional controller (NNPC) are proposed to enhance the robustness of the PI controller. A theoretical analysis, simulation and experimental results all demonstrate that the proposed model-reference robust control scheme can improve the performance of an induction motor drive with time delay, and can reduce its sensitivity to system parameter variations and load torque disturbances.

A path following algorithm for mobile robots

Abstract: This paper considers path following control for a robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The platform is four-wheel steered and four-wheel driven. A diesel engine powers the wheels via a hydraulic transmission. The robot uses a Real Time Kinematic Differential Global Positioning System to determine both position and orientation relative to the path. The deviation of the robot to the desired path is supplied to two high level controllers minimizing the orthogonal distance and orientation to the path. Wheel angle setpoints are determined from inversion of the kinematic model. At low level each wheel angle is controlled by a proportional controller combined with a Smith predictor. Results show the controller performance following different paths shapes including a step, a ramp, and a typical headland path. A refined tuning method calculates controller settings that let the robot drive as much as possible along the same path to its setpoint, but also limit the gains at higher speeds to prevent the closed loop system to become unstable due to the time delay in the system. Mean, minimum and maximum orthogonal distance errors while following a straight path on a paving at a speed of 0.5 m/s are 0.0, ?2.4 and 3.0 cm respectively and the standard deviation is 1.2 cm. The control method for four wheel steered vehicles presented in this paper has the unique feature that it enables control of a user definable position relative to the robot frame and can deal with limitations on the wheel angles. The method is very well practical applicable for a manufacturer: all parameters needed are known by the manufacturer or can be determined easily, user settings have an easy interpretation and the only complex part can be supplied as a generic software module.

Slewing type working vehicle

Abstract: PURPOSE:To prevent the occurrence of uncontrollable slewing, by a method wherein a direct signal responding to a control distance and a control direction of a control lever is outputted from a potentiometer to a control valve, and meanwhile, a control signal is outputted by means of a detecting signal for a slewing angle or a stop angle, and the two signals are selected. CONSTITUTION:A potentiometer 6 is coupled to a control lever 5 of a slewing table for interlocking. By means of an output voltage from the potentiometer 6, a first control circuit 7 outputs a signal, responding to the control direction of a control lever 5, to an electromagnetic proportional control valve 10 which controls forward and reverse turning and governing of the slewing table. Meanwhile, the proportional control valve 10 and a second controller 8 outputs a signal so that the slewing table is slewed in a direction responding to control of the control lever 5 and the slewing table stops slewing by means of outputs from an angle to car body detecting sensor 14 and a stop angle to car body setter 15 of the slewing table. Further, a circuit 18 for selecting an output from the first control circuit is installed to the output circuit of the second controller.