Ana M. Djuric

Robust fault detection of turbofan engines subject to adaptive controllers via a Total Measurable Fault Information Residual (ToMFIR) technique.

This paper provides a new design of robust fault detection for turbofan engines with adaptive controllers. The critical issue is that the adaptive controllers can depress the faulty effects such that the actual system outputs remain the pre-specified values, making it difficult to detect faults/failures. To solve this problem, a Total Measurable Fault Information Residual (ToMFIR) technique with the aid of system transformation is adopted to detect faults in turbofan engines with adaptive controllers. This design is a ToMFIR-redundancy-based robust fault detection. The ToMFIR is first introduced and existing results are also summarized. The Detailed design process of the ToMFIRs is presented and a turbofan engine model is simulated to verify the effectiveness of the proposed ToMFIR-based fault-detection strategy.

Graphical representation of the significant 6R KUKA robots spaces

Trajectory planning for serial 6 degree of freedom (DOF) machinery systems is demanding due to complex kinematic structure which affects the machinery tool fame, position, orientation and singularity. These three characteristics represent the key elements for production planning and layout design of the manufacturing systems. Both, simple and complex machine trajectory is defined as series of connected points in 3D space. Each point is defined with its position and orientation related to the machines base frames. To visualize the machines reachable space, the work envelope is calculated and graphically presented as very well known machines property. A methodology to predetermine regions of feasible tool orientation (work window) is analytically and graphically presented. The work envelope boundary is generated using the filtering points algorithm, while work window is generated using either empirical or analytical methods. The singularity regions are calculated by finding the determinant of the reconfigurable Jacobian matrix. These three tool path characteristics represent three different spaces which are identified both analytically and graphically and plotted in Cartesian space using MATLAB tools. The singularity regions will be represented within the workspace and work window for a single machinery kinematic structure. The KUKA KR robot family is used as a case study.

Contribution to the modeling of cable-suspended parallel robot hanged on the four points

This paper describes a novel mathematical model of the Cable-suspended Parallel Robot. The complex system is made to accurately carry camera in the 3D space. The geometric relationship between the camera motion in the Cartesian coordinates and motors angular positions is defined by the Jacobian matrix, which represents the solution of the kinematic problem. The solution of the calculated matrix directly depends on the systems geometry. The adopted Jacobian matrix is used for calculation of the dynamic model of the Cable-suspended Parallel Robot. Two numerical examples are used to illustrate practical usefulness of the proposed mathematical model and its validation. The final goal of this research is to ensure the accurate and highly automated guidance of the camera in 3D space with the minimal involvement of the human factor for the task generation.

The rigid S-type cable-suspended parallel robot design, modelling and analysis

†Mihajlo Pupin Institute, The University of Belgrade, Volgina 15, 11000 Belgrade, Serbia ‡Wayne State University, 4855 Fourth St. Detroit, MI 48202, USA §School of Electrical Engineering, The University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade, Serbia ¶Innovation center of School of Electrical Engineering, The University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade, Serbia

Effective Work Region Visualization for Serial 6 DOF Robots

Optimal serial 6 degree of freedom (DOF) robot path planning has challenges due to the kinematic structures, singularity conditions, and the practical reach limits due to the a path-fixture-end effector orientation and design-robot structure combination. Previous research has been done to define and visualize the functional reach limits for a robot-end effector orientation-end effector tool geometry set. This is expanded and combined with singularity region analyses to be able to visualize the total effective travel path regions for a target application (i.e., FANUC, ABB, or Comau robot families) using the MATLAB toolbox. Visualization tools that represent both the functional work region or work window and singularity regions are presented. This research will provide designers the ability to assess a wide range of industrial robot configurations comprehensively at the design or redesign stages as the valid bounded region defined in this work can be employed for subsequent downstream optimization related to velocity and acceleration control.

The mathematical model of aerial robot in purpose increasing of its autonomy

The purpose of this research is to implement the presented results and possibly improve the model for the future modernization, autonomy and intelligent behavior of the aerial robot named Cable Suspended Parallel Robot -CPR. Visionary speaking these high-set goals were a strong incentive to define highly reliable kinematic and dynamic model of the CPR system, which will be used for the control purposes.

Future directions for implementation of aerial robot

The aim of this paper is to highlight the importance of forming a mathematical model of Cable-suspended Parallel Robot - CPR (aerial robot), since only that way CPR provides precise guidance in the area. Only highly intelligent control systems, based on high authentic system mathematical model, can provide the realization of very complex tasks. The established mathematical model provides an opportunity to modernize CPR significantly and to make its application become much wider.

Singularity Analysis for a 6 DOF Family of Robots

Path planning for serial 6 degree of freedom (DOF) robot based systems is challenging due to their kinematic structure, the behaviour of robot based on the configuration, and singularity conditions. Understanding the singularity conditions and zones is critical for both single robot applications, and robot cells. Visual representations of singularity zones will help process designers develop valid travel paths and layout designs. MATLAB tools are employed to represent the singularity zones using fundamental kinematic equations. The target application for this research is the FANUC family of serial 6 DOF robots, and the identified singularity regions are plotted in 2D and 3D Cartesian space.

Robust fault detection of turbofan engines subject to adaptive controllers via a ToMFIR technique

This paper provides a new design of robust fault detection for turbofan engines with adaptive controllers. The critical issue is that the adaptive controllers can depress the faulty effects such that the actual system outputs remain the pre-specified values, making the fault detection difficult. In addition, observer-based fault-detection strategies are not always reliable because the observer gain may be selected large due to the consideration of stability, robustness or performance, leading to the size of output estimation errors, which are used as fault-detection residuals, small. To solve this problem, the Total Measurable Fault Information Residual (ToMFIR) technique is adopted to detect faults in turbofan engines with adaptive controllers. To this end, a bank of systems, each corresponding to a particular fault, is formulated by reorganizing the considered uncertain engine model. Each system in the bank is first transformed into two subsystems. Then, a ToMFIR is designed for the disturbance-free subsystem to generate a fault-detection residual. In this manner, a bank of ToMFIRs is constructed to detect a specific fault source. The advantage of such a design is that all of ToMFIRs in the bank will together declare the occurrence of a single fault. This design is a ToMFIR-redundancy-based robust fault detection. Detailed design process of the ToMFIRs is presented and a turbofan engine model is simulated to verify the effectiveness of the proposed ToMFIR-based fault-detection strategy.

Applications of electro-hydraulics actuators

Electro-hydraulic systems can be used in robust robotics systems that have to carry heavier loads efficiently. Electrical drives have proven to be reliable and easy to control, but they may have problems when it comes to holding a position under load for a long period of time. Hence, electro-hydraulic systems are gaining more attention in applications that need good positioning and force feedback.