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Dou H.,Beihang University | Wang S.,Science and Technology on Aircraft Control Laboratory
Proceedings of the 2011 6th IEEE Conference on Industrial Electronics and Applications, ICIEA 2011 | Year: 2011

This paper presents a control algorithm to address the leveling issue for lifting vehicle. The leveling system is achieved by electro-hydraulic system because of its advantages, such as small size-to-power ratios and so on. As four cylinders used to achieve synchronization, the issue of cylinder redundancy appears. In order to address this issue, the approach that two cylinders are only allowed to move in the same time is used. The two moving cylinders both are at the front of vehicle or at the back of vehicle. So the leveling issue is converted to motion synchronization of dual-cylinder. The design of controller to achieve motion synchronization of dual-cylinder is presented. The synchronization controller is a double loop controller. Inner-loop controller is a PID controller that is used to achieve the tracking performance of individual cylinder. Outer-loop controller is a compensation controller that is used to compensate the synchronization error of the cylinder the displacement of which is smaller. Simulation results on a dual-cylinder system verified the effectiveness of the proposed approach. © 2011 IEEE. Source


Wang L.,Beihang University | Wang X.,Science and Technology on Aircraft Control Laboratory
Applied Mechanics and Materials | Year: 2013

Artificial muscle is a new style of actuator with novel working principle, which owns the advantages of compact structure, high power-to-weight ratio, compliance and easy application. Pneumatic artificial muscle (PAM) is usually used in robotics, medical auxiliaries and other small force output occasions nowadays. However, it suffers problems of small power, hysteresis and poor repeatability. A kind of artificial muscle working at high pressure was researched. Different muscle styles are compared and MicKibben structure is selected while fluid media is determined. Furthermore, factors of geometry and material properties, which limit the ultimate pressure, are analyzed. Formulas and simulations verify the influence of limitation and help to calculate key parameters of 18MPa artificial muscle. Data show that it is possible in theory to design high pressure artificial muscle by overall consideration of initial diameter, initial contraction angle and material properties, initial length only influent the stroke. © (2013) Trans Tech Publications, Switzerland. Source


Shi J.,Northwestern Polytechnical University | Shi J.,Science and Technology on Aircraft Control Laboratory | Qu X.,Northwestern Polytechnical University | Bi K.,Northwestern Polytechnical University
Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University | Year: 2014

When control allocation method based mathematical programming is used to solve the multi-objective allocation problem, it is needed to establish the allocation objectives of the various phases of flight of the aircraft, and then to use linear programming or quadratic programming method for solving. Although the method can get an optimal solution, it neglects the physical differences among the surfaces and dispatches all the control surfaces at the same time, which is not beneficial to the algorithm's engineering applications and to system reliability. Especially the algorithm requires automatic mode switch which greatly increases the complexity of control system design. In order to solve the problem, an allocation method based on attainable moment subset is proposed. The method first calculates the attainable moment subset (AMS) of different effector groups and then chooses a group as the master control surfaces according to its AMS structure characteristic together with its radar reflectivity characteristics and resistance characteristics. So Conventional layout aircraft control law design methods and experience can still be used. When the master control surfaces can not meet the demand for the available torque, auxiliary control surfaces and thrust vector control surfaces will be dispatched; and the management of the auxiliary control surfaces is in accordance with the priority of the radar reflectivity. The simulation results and their analysis show preliminarily that: (1) the proposed method avoids the faults of the allocation methods based on mathematical programming; (2) the way of managing the auxiliary control surfaces and thrust vector control surfaces by available three-axis torques is feasible and a reasonable control allocation design is achieved. Source


Li K.,Beihang University | Li K.,Civil Aviation Management Institute of China | Wang S.,Beihang University | Wang S.,Science and Technology on Aircraft Control Laboratory | Sullivan J.P.,Purdue University
Applied Thermal Engineering | Year: 2013

This paper proposes a novel thermal network to calculate the maximum temperature-rise of hollow cylinder geometry, which is named as the maximum thermal network. Linear transformation and local linear fitting are applied to make the maximum temperature-rise of hollow cylinder represent by the maximum thermal network. One compensation unit is added into the maximum thermal network for the elimination of the error introduced by linear fitting. Moreover, an iterative algorithm is presented in this paper, which is used in the calculation of the maximum temperature-rise for the system composed of more than one hollow cylinder. At the end of the paper, the thermal model of an electric motor is built by the maximum thermal network whose accuracy is verified by comparing with finite-element analysis. © 2012 Elsevier Ltd. All rights reserved. Source


Dou H.,Beihang University | Wang S.,Beihang University | Wang S.,Science and Technology on Aircraft Control Laboratory
Mechanism and Machine Theory | Year: 2013

High-performance robust adaptive synchronization motion control for multiple two-link manipulators with parametric uncertainties and uncertain nonlinearities is considered. The proposed control approach considers synchronization motion as constraint motion. The Lagrange multiplier method is used to derive the coupling dynamic characteristics caused by synchronization constraint conditions. In order to track desired trajectories while maintaining the synchronization motion, a motion/force control strategy is developed. Motion control is used to track desired trajectories for independent joints. Force control is used to realize the synchronization motion by guaranteeing the constraint force to be zero. In order to improve the performance of force control, a first-order low-pass filter is introduced. Simulation results demonstrate that the proposed method can effectively improve the performance of synchronization motion and tracking performance compared with other methods. © 2013 Elsevier Ltd. All rights reserved. Source

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