scholarly journals Asymptotic tracking position control with active oscillation damping of a multibody Mars vehicle using two artificial augmentation approaches

Author(s):  
Daniel Bodmer ◽  
Michael Krenmayr ◽  
Florian Holzapfel

AbstractThe Valles Marineris Explorer Cooperative Swarm navigation, Mission and Control research project aims to explore the Valles Marineris canyon system on Mars with, among others, multibody rotary-wing unmanned aerial vehicles (UAVs) comprising of a hexrotor system and a helium-filled balloon being attached to it by means of a rope. In this paper, we develop a high-fidelity closed-loop control system in MATLAB® and Simulink™ to present the application of an adequate flight controller guaranteeing (1) asymptotic tracking position control of the multibody flight system, (2) suppression of the balloon’s swinging motion in forward flight case, and (3) stabilization of the rope angle around its equilibrium for steady-state conditions. Applying feedback linearization for the outer loop and analytical backstepping for the inner loop of a nonlinear cascaded control design model of the hexrotor system, we propose an extension of the baseline flight controller by two artificial augmentation approaches to cope with the balloon dynamics. Basically, by utilizing oscillation damping feedbacks of the uncertain plant which are applied as additional commands to either the inner or the outer loop’s reference model. Simulation results are presented for an eight-shaped flight maneuver at the bottom of Valles Marineris proving that the augmentation units increase the flight controller capabilities to suppress modeling errors artificially—without changing the baseline control laws. The augmentation units actively damp the balloon motion in the forward flight case for non-steady-state conditions to counteract the rope oscillations and finally stabilize the rope angle around its equilibrium, so that the Mars vehicle is able to reach a steady-state in position when its extraterrestrial mission profile is successfully completed.

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Tianqian Xia ◽  
Xianghua Huang

Abstract A method of variable speed control system for turboprop engine is presented in this paper. Firstly, the steady operation state of turboprop engine is analyzed, and the operating line is figured out in the steady state characteristic diagram, which is the design basis of Engine Thrust Management System (ETMS). Secondly, the reference model sliding mode multivariable control is used to design the control law to follow the speed instructions given by ETMS. Finally, the optimization of the minimum fuel consumption operating curve is realized, and the control system designed is applied to a numerical model of a turboprop engine. The simulation results show that compared with the constant speed control system, the variable speed control system can reduce the specific fuel consumption by 2.37 % on average and 3.1 % in steady state conditions. Furthermore, the method can enable the pilot to manipulate the turboprop aircraft by using only one throttle lever, which can greatly reduce the pilot operation burden.


Author(s):  
Joseph Bowkett ◽  
Rudranarayan Mukherjee

While the majority of terrestrial multi-link manipulators can be considered in a purely kinematic sense due to their high stiffness, the launch mass restrictions of aerospace applications such as in-orbit assembly of large space structures result in low stiffness links being employed, meaning dynamics can no longer be ignored. This paper seeks to investigate the suitability of several different open and closed loop control techniques for application to the problem of end effector position control with minimal vibration for a low stiffness space based manipulator. Simulations of a representative planar problem with two flexible links are used to measure performance and sensitivity to parameter variation of: model predictive control, command shaping, and command shaping with linear quadratic regulator (LQR) feedback. An experimental testbed is then used to validate simulation results for the recommended command shaped controller.


Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 313
Author(s):  
Rui Zhang ◽  
Jun Peng ◽  
Bin Chen ◽  
Kai Gao ◽  
Yingze Yang ◽  
...  

Active braking control systems are vital for the safety of high-speed trains by leading the train operation at its maximum adhesion state. The train adhesion is a nonlinear function of the slip ratio and varies with the uncertain wheel-rail contact conditions. A nonlinear active braking control with rapid and accurate tracking performance is highly required for train braking systems. This paper proposes a novel prescribed performance active braking control with reference adaptation to obtain the maximum adhesion force. The developed feedback linearization controller employs a prescribed performance function that specifies the convergence rate, steady-state error, and maximum overshoot to ensure the transient and steady-state control performance. Furthermore, in the designed control approach, a continuous-time unscented Kalman filter is introduced to estimate the uncertainty of wheel-rail adhesion. The estimation is utilized to represent uncertainty and compensate for the prescribed performance control law. Finally, based on the estimated wheel-rail adhesion, an on-line optimal slip ratio generation algorithm is proposed for the adaptation of the reference wheel slip. The stability of the system is provided, and experiment results validate the effectiveness of the proposed method.


2021 ◽  
Vol 233 ◽  
pp. 01051
Author(s):  
Tianze Miao ◽  
Xiaona Liu ◽  
Siyuan Liu ◽  
Lihua Wang

The bi-directional DC / DC converter in DC microgrid is a typical nonlinear system which has large voltage disturbance during lead accumulator charging and discharging. In order to solve the problem of voltage disturbance, the linearization of the converter is realized by exact feedback linearization, and the sliding mode controller is designed by using exponential approximation law. The simulation results show that the method has fast response speed, strong anti-interference ability and good steady-state characteristics.


Author(s):  
Hardik K. Lakhani ◽  
N. Arun

In this paper, an approach to generate robust control algorithm for the single phase PFC boost converter is presented. This control rules provide fast output response while maintaining high power factor. This approach is based on derivation of the control functions for both current loop and voltage loop which is multi-loop control structure. Designing of the control parameters are based on the required transient and the steady-state responses. Due to application of feedback linearization the performance of the of this control scheme is robust under all practical conditions. This method eliminates the nonlinearity and the dependence of the error dynamics on the input disturbance. Experiments are conducted to evaluate the control performance.


Author(s):  
Ehab S. Ghith ◽  
◽  
Mohamed Sallam ◽  
Islam S. M. Khalil ◽  
Mohamed Youssef Serry ◽  
...  

One of the main difficult tasks in the field of micro-robotics is the process of the selection of the optimal parameters for the PID controllers. Some methods existed to solve this task and the common method used was the Ziegler and Nichols. The former method require an accurate mathematical model. This method is beneficial in linear systems, however, if the system becomes more complex or non-linear the method cannot produce accurate values to the parameters of the system. A solution proposed for this problem recently is the application of optimization techniques. There are various optimization techniques can be used to solve various optimization problems. In this paper, several optimization methods are applied to compute the optimal parameter of PID controllers. These methods are flower pollination algorithm (FPA), grey wolf optimization (GWO), sin cosine algorithm (SCA), slime mould algorithm (SMA), and sparrow search algorithm (SSA). The fitness function applied in the former optimization techniques is the integral square Time multiplied square Error (ISTES) as the performance index measure. The fitness function provides minimal rise time, minimal settling time, fast response, and no overshoot, Steady state error equal to zero, a very low transient response and a non-oscillating steady state response with excellent stabilization. The effectiveness of the proposed SSA-based controller was verified by comparisons made with FPA, GWO, SCA, SMA controllers in terms of time and frequency response. Each control technique will be applied to the identified model (simulation results) using MATLAB Simulink and the laboratory setup (experimental results) using LABVIEW software. Finally, the SSA showed the highest performance in time and frequency responses.


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