Active Disturbance Rejection Control of Certain Balanced and Positioning Electro-Hydraulic Servo System Based on Neural Network
For certain balance and positioning of electro-hydraulic servo system existing nonlinear, the active disturbance rejection control (ADRC) has many adjustable parameters which are difficult to regulate, so active disturbance rejection control with neural network (NN-ADRC) is developed in this paper. The method uses neural network self-learning ability, through a single neuron adaptive configuration parameters to complete an online self-tuning parameters, while taking advantage of RBF neural network as identifier to identify the controlled object gradient information. Simulation results show that: the controller parameters are reduced significantly, and effectively inhibit the system unbalance force disturbance and realize the accurate positioning. It also has fast response speed, no overshoot, and high steady-state accuracy.
Development of Technologies to Apply Refractory Metals to Large Caliber Gun Bores
To increase the service life of large caliber naval guns, several technologies were evaluated by the Office of Naval Research for their ability to apply a refractory metal bore surface that would survive the severe thermal, chemical and mechanical environment. These technologies were evaluated using gun firing tests designed to produce a bore surface condition that replicated the intended application. Tests were conducted in 45 mm, 76 mm and 155 mm scale with rapid fire conditions evaluated at both 76 mm and 155 mm scale. Where possible the results have been compared to a chrome plated sample subjected to the same firing conditions.
A novel hybrid control strategy for trajectory tracking of fast tool servo
By integrating the fractional order PID (FPID) with repetitive control (RC), a hybrid control strategy is proposed for fast tool servo (FTS) to improve the trajectory tracking performances. A differential evolution algorithm is used to determine the optimal parameters of FPID controller. The control performances of conventional PID (CPID) and FPID controllers are compared by numerical simulation based on the response time and tracking accuracy, the results verify that FPID controller is of more excellent control performance. In order to improve the tracking performance of FTS on periodical command signals, RC is further integrated into the FPID control system. The feasibility and availability of the proposed hybrid controller has been examined by tracking control of a sinusoidal command, the results show that the tracking error of the hybrid controller is 1/11.7 and 1/4.5 times of CPID and FPID, respectively, and it is suitable for the trajectory tracking control of FTS.