Papers by Keyword: LQR

Abstract: Accelerator has been widely applied to high energy, low energy physics, Medical environmental and military fields, etc. The magnet power supply is one of the most important parts of the accelerator. At the beginning, the state-space model of the magnet power supply has been established by modern control theories. Then, the PSO algorithm has been used for the weight matrices optimization of LQR controller in order to ensure that the magnet power supply can provide a magnetic field quickly which the accelerator required. The experimental results indicate that the method that proposed in the paper can meet the requirements of fast output response of the system and each control index of the LQR controller is obviously superior to that by the traditional method.

Abstract: Micro-structure injection molding machine is mainly used for processing the plastic products in micron-size or with micro-structures. This paper focuses on the design and control of the clamping mechanism of micro-structure injection molding machine. Firstly, the deformation of the clamping mechanism was analyzed. The simulation results shows that the clamping force is 5.0051×10⁵N, and it’s bigger than the design value 500kN. Secondly, the kinetic characteristic of the clamping was simulated by ADAMS software. The curves of the displacement, velocity, clamping force of moving platen were analyzed. Thirdly, the control model of clamping mechanism was established. And the LQR controller was designed and simulated by Matlab. The rise time is 0.010s, the settling time is 0.026s and the steady-state is 0.307m.

Abstract: In practice, the key problem to apply LQR optimal control method is how to correctly choose the weighted matrix of performance index. At present, there is no formulaic approach for this problem. To obtain the satisfying results, people must repeat to test many times. This kind of LQR control method based on genetic algorithms, which can obtain satisfying control results at first hand, is presented for triple inverted pendulum system. The method optimizes the Q-matrix by using genetic algorithms, selects trace of the result of Riccati equation as the objective function. The control problem of triple inverted pendulum is resolved successfully. The simulation results prove that the control effect by this method is better than the other methods mentioned in the references.

Abstract: Two self-balancing robot is a nonlinear, multivariable, intrinsically unstable motion control system, For traditional LQR controller feedback matrix optimization problem is difficult to determine, Particle swarm optimization algorithm to optimize the LQR controller feedback matrix, The simulation results show, Utilizing particle swarm optimized LQR controller improves the stability of the system, reducing the system overshoot and oscillation frequency.

Abstract: Most of modern tall buildings using lighter construction materials are more flexible so could be excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety. The optimal control technique for reducing along-wind vibration of a tall building based on the linear quadratic regulator (LQR) is presented in this work. Actively controlled reduced along-wind vibration response is obtained from the tall building installed in an active mass damper (AMD) with a LQR controller. Fluctuating along-wind load is generated using numerical simulation method, which can formulate a stationary Gaussian white noise process. Simulating wind load in the time domain using known spectra data of fluctuating along-wind load is particularly useful for estimation of windinduced vibration which is more or less narrow banded process such as a along-wind response of a tall building. In this work, fluctuating along-wind load acting on a tall building treated as a stationary Gaussian white noise process is simulated numerically using the along-wind load spectra proposed by G. Solari in1992. And using this simulated along-wind load estimated the reduced along-wind vibration response of a tall building installed in an AMD with a LQR controller.

Abstract: This paper focuses on an active vibration isolator based on voice-coil motor (VCM). The isolator may reduce the vibration in the range from 5 to 100Hz in one DOF which can provide the payloads on a satellite a more stable working environment. A VCM is designed and optimized to provide enough feedback force; the state-space model is established according to the basic governing equations of the VCM. The LQR controller based on a reduced-order observer is designed for an output feedback control system. The vibration isolation system is verified by numerical simulations and experiments in which the VCM is installed between the payload and the excitation bottom, with an accelerometer located on the payload in the vertical direction. Both the simulation and experiment results show that the vibration of the payload is reduced effectively using the voice-coil actuator designed here.

Abstract: A torsional controller is proposed for the motor-gearbox/differential drive system of electric vehicles to suppress the torsional vibration of the system. The drive system is simplified to a 2-mass spring damper system, and the state-space equation is set up. A controller consisting of linear quadratic regular (LQR) and state observer is designed. The results of simulation show that LQR can suppress the torsional vibration effectively, enhancing the driving performance of the vehicle.

Abstract: Walking robot has complicate structure and strong ability to adapt ground conditions, and it is difficult to control. To realize dynamic walking of the humanoid robot, we have to establish robot dynamic models, design the control algorithm for gait and the stability postures. In this paper, study dynamic model and control system of a 7-links biped robot, build parameterized simulation model of biped walking robot, proceed gait planning and simulation experiments in the simulation surrounding, and get some experiment results. Compare the experiment data with the theoretic stable region and confirm that the biped walking robot as leg mechanism has good stability of static walking, and provide theoretic and data information for further work.

Abstract: An attitude control system of a spinning spacecraft with internal moving mass is presented in this paper. This system consists of a rigid body and two internal radial moving masses. The mathematical model, including attitude kinematics and nonlinear dynamics equations, is established based on Newtonian mechanics. The control law is designed based on the linear-quadratic-regulator (LQR) theory. The performance of the controller is demonstrated in numerical simulation, and the response shows that the attitude control system is stable and effective.

Abstract: Modern tall buildings using high strength and lighter construction materials are more flexible so could be excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety. Recently, many studies have been advanced in using actuator force as an active control force based on the linear quadratic optimum control theory .It needs to predict the wind-induced response and the optimum control force to reduce the excessive wind-induced vibration. It takes a lot of time and cost to do wind tunnel test needed it, so numerical simulation approach instead of that is recommended sometimes. Simulating wind load in the time domain using known spectra data of fluctuating wind load is particularly useful for some prediction of windinduced vibration which is more or less narrow banded process such as a along-wind response of a tall building. In this study, fluctuating along-wind load acting on a tall building treated as a stationary Gaussian white noise process was simulated numerically in the time domain using the along-wind load spectra proposed by G.Solari in1992. And using this simulated along-wind load estimated the reduced along-wind vibration response of a tall building which has an active tuned mass damper (ATMD) installed based on the linear quadratic regulator (LQR) control method.