The paper presents a phenomenon of directional change in the case of a LQR controller applied to multivariable plants with amplitude and rate constraints imposed on the control vector, as well as the impact of the latter on control performance, with the indirect observation of the windup phenomenon effect via frequency of consecutive resat- urations. The interplay of directional change of the computed control vector with control performance has been thoroughly investigated, and it is a result of the presence of con- straints imposed on the applied control vector for different ratios of the number of control inputs to plant outputs. The impact of the directional change phenomenon on the control performance (and also on the windup phenomenon) has been defined, stating that performance deterioration is not tightly coupled with preservation of direction of the computed control vector. This conjecture has been supported by numerous simulation results for different types of plants with different LQR controller parameters.
In the paper the analysis of random vibration of an actively damped laminated plate with functionally graded piezoelectric actuator layers is presented. The simply supported plate is subjected to stochastic loading represented by a uniformly distributed pressure. The random input is assumed as a Gaussian sta- tionary and ergodic process. The actuators are regarded as a multi-layer structure arranged of piezofiber composite sub-layers. The sub-layers differ each other with amount of PZT (lead-zirconate-titanate) fibers and are stacked to achieve a desired change of the PZT volume fraction through the actuator thickness. The gradation scheme of constituents and material properties are estimated by parabolic and power functions. Numerical simulations are performed to recognize the influence of the applied random excita- tions and the actuator properties gradations on the characteristics of the stochastic field of active plate deflection i.e. power spectral density, autocorrelation function and variance
It is shown that decrease and damping of the traction force at the end of the plunger move is possible not only due to application of a special keeper design, but also due to change of the plunger shank geometric form. The computer modeling with the use of finite element method is used to analyze the influence of system geometry on force distribution along plunger movement. The damping effect is confirmed when special shape plunger shanks are used.
Modern and innovative road spreaders are now equipped with a special swiveling mechanism of the spreading disc. It allows for adjusting a symmetrical or asymmetrical spreading pattern and provides for the possibility to maintain the size of the spreading surface and achieve an accurately defined spreading pattern with spreading widths. Thus the paper presents a modelling and control design methodology, and the concept is proposed to design high-performance and optimal drive systems for spreading devices. The paper deals with a nonlinear model of an electric linear actuator and solution of the new intelligent/optimal control problem for the actuator.
By the use of different distribution methods of dynamical characteristics in the form of slowness function, mechatronic discrete systems have been synthesized. Each model consists of mechanical discrete part and a piezostack actuator connected to LxRxCx external network that has to comply with dynamical requirements in the form of poles and zeros. External network can work within different configurations. In this paper, one investigates the influence of negative parameters of stiffness in mechanical replacement models and capacitance in final mechatronic structures, after dimensionless transformations and retransformations.
In this paper we propose an original configuration of a compliant mini-gripper for handling chemicals. The compliant mini-gripper is 3D modeled and analyzed with finite element method. To use it in a wider range of containers designed for laboratories we made several variants of fasteners. In order to obtain a functional prototype in a scale appropriate to characterize the system, we determined the material properties of the gripper and developed an experimental stand for characterizing the system with mini-gripper. Finally, we compared the movements of the experimental grip, made according to the movement of the bellows type actuator, determined based on, analytical and numerical results.
In this paper an active multimodal beam vibration reduction via one actuator is considered. The optimal actuator distribution is analyzed with two methods: an exact mathematical principles and the LQ problem idea. It turned out that the same mathematical expressions are derived. Thus, these methods are equivalent.
This paper presents the results of Pilot Assisting Module research performed on two light aircraft flight simulators developed in parallel at Brno University of Technology, Czech Republic, and Rzeszow University of Technology, Poland. The first simulator was designed as an open platform for the verification and validation of the advanced pilot/aircraft interface systems and inherited its appearance from the cockpit section of the Evektor SportStar. The second flight simulator, the XM-15, has been built around the cockpit of a unique agriculture jet Belfegor. It introduced a system architecture that supports scientific simulations of various aircraft types and configurations, making it suitable for conceptual testing of Pilot Assisting Module. The XM-15 was initially designed to support research on advanced flight control systems, but due to its continuing modernization it evolved into a hardware-in-the-loop test-bed for electromechanical actuators and autopilot CAN based controller blocks. Pilot-in-the-loop experiments of proposed Pilot Assisting Module revealed favorable operational scenarios, under which the proposed system reduces the cockpit workload during single pilot operations.