This paper investigates the modification of a conventional quadrotor helicopter Unmanned Aerial Vehicle (UAV) by adding two actuators to the helicopter for increased hardware redundancy and enhanced Fault-Tolerant Control (FTC) capability. On one hand, this redundancy improves the helicopter's safety margin and on the other hand, it extends the FTC methods that can be flying-tested on the quadrotor with more severe faults/damages. For illustration, control re-allocation is employed as a fault-tolerant control method in the presence of actuator faults. Some experimental results using the quadrotor testbed at the Networked Autonomous Vehicles (NAV) Lab of the Department of Mechanical and Industrial Engineering of Concordia University are given to illustrate the capabilities of the modified UAV system. The MQ-X4 shows that existence of actuator redundancy allows the quadrotor-type helicopter to accommodate actuator faults to some level without the need for FTC. The modified system also extends the FTC methods that can be applied and flying-tested. However, additional motors can bring many difficulties in hardware which makes the work not very easy to accomplish. These difficulties include the extra payload and the faster drain of electrical current from the on-board Lithium-Polymer batteries which has a direct effect on flight time. The immediate future work will focus on adding two more additional motors to build an MQ-X8 UAV while using smaller, lighter and more powerful batteries. In addition, this paper employs the Pseudo-Inverse method for control allocation and re-allocation but other methods will also be tested as well. Finally, it should be noted that as mentioned earlier in the paper, an FDD module is required to provide the control allocation/reallocation module with information about the occurred faults. However, it is also possible to design a robust controller in combination with control allocation (with the matrix W fixed to the identity matrix) and in this case, an FDD module may not be required. This point will also be considered in future work.
Control allocation and re-allocation for a modified quadrotor helicopter against actuator faults
2012
6 Seiten, 10 Bilder, 16 Quellen
Aufsatz (Konferenz)
Englisch
2012-2511 Control Allocation for a Modified Quadrotor Helicopter Based on Reliability Analysis
British Library Conference Proceedings | 2012
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