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KARI, South Korea

Choi S.W.,Korea Aerospace Research Institute | Choi S.W.,Smart Development Center | Kim J.M.,Korea Aerospace Research Institute | Kim J.M.,Smart Development Center
Journal of Aircraft | Year: 2010

The aerodynamic performance of the tiltrotor unmanned aerial vehicle proprotor was investigated. The proprotor of the power test rig was built to 40% scale of the Smart UAV. The test was based on the Mach scale test, which sets the maximum rotational speed of the scaled proprotor to 4012 rpm in hover mode. The test rig of the 40% scale proprotor was composed of proprotors, electric motors, supports and tilting structures, power and cooling systems, and a control system. An induction type, water-cooling, geared motor capable of 50 hp and 4012 rpm was used to drive the proprotor. A force component (Tz) and two moment components (Mx, My) of the proprotor hub were measured by four load cells installed in the front section of the motor assembly. The test rig was installed on the turntable of the wind-tunnel test section to enable a yawing test. The results showed that the power of the rotor had a higher value near a tilt angle of 45 deg and reached its maximum at 90 deg of tilt. Source


Yoo C.-S.,Smart Development Center | Kang Y.-S.,Smart Development Center | Park B.-J.,Smart Development Center
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

The Smart UAV is the tilt rotor type of unmanned aerial vehicle that has been developed by KARI since 2002. According to the characteristics of tilt rotor aircraft, it has a flight envelope of VTOL(vertical take-off and landing) and high cruise speed. Because the conversion flight between helicopter and airplane mode is required, the actuator system of Smart UAV control surfaces has 12 actuators and 5 controllers for nacelle tilt as well as flaperon, elevator and rotor. Based on Fly-By-Wire system, all actuators except for elevator are an electric linear type with dual motors and RVDT sensors. Actuators for elevator are an electric rotary type with single motor and are equipped on each control surface of two elevators. Controllers for activating actuators were developed in domestic company by interfacing with flight control computer through ARINC 429 and with actuators through analog cable. To accomplish the safe conversion flight between helicopter and airplane mode, a role change of control surfaces according to tilting angle is also required on time. This requires the high reliable and accurate performance for actuator system that consists of actuators, controllers and flight control computer. Prior to actual flight test, this actuator control system was tested and evaluated by Hardware-In-Loop(HIL) simulation on the ground. This paper describes the configuration of actuator control system and HILS system of Smart UAV and gives the results of HILS test. ©ICROS. Source


Kang Y.-S.,Smart Development Center | Park B.-J.,Smart Development Center | Yoo C.-S.,Smart Development Center | Kim Y.-S.,Smart Development Center | Koo S.-O.,Smart Development Center
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

The ground test results of Smart UAV are described. The ground test consists of HILS, iron-bird test, 4-DOF (degrees of freedom) ground rig test, and tethered hover test. One of the main purposes of ground test is to evaluate the integrated flight control system including a digital flight control computer, GPS/INS sensor, air data sensors, etc as well as ground control system (GCS). The performances of whole flight control systems were evaluated. Rotor speed was kept constantly by the rotor governor even during collective sweep and pitch/roll attitude SCAS (Stability and Control Augmentation System) showed good handling qualities performance during 4-DOF and tethered hover test. These control laws and guidance law will be evaluated during the flight test of envelope expansion planed for this year. This paper presents the ground test results and the procedure for Smart UAV. ©ICROS. Source


Kang Y.-S.,Smart Development Center | Park B.-J.,Smart Development Center | Cho A.,Smart Development Center | Yoo C.-S.,Smart Development Center | Koo S.-O.,Smart Development Center
International Conference on Control, Automation and Systems | Year: 2011

Flight test results of flying qualities for Helicopter mode of Smart UAV are described. Flight test items in helicopter mode include manual and automatic stick control as well as hold and navigation flight including automatic take off and landing. One of the main purposes of helicopter mode flight test is to evaluate the handling qualities in low speed region where nacelle angles are greater than 80 deg. Rotor speed was controlled by the rotor governor without electric engine control after engine start. Position holding GPS stick mode and pitch/roll attitude SCAS (Stability and Control Augmentation System) showed good handling qualities performance during helicopter flight test. These control laws are also the basis both of conversion mode and airplane mode. All flight test described in this paper were controlled by external pilot (EP) using augmented GPS stick mode which comprise of 3 axis speed command and yaw rate command as well as position/heading hold at a neutral stick position. This paper presents the flight test result of flying qualities for helicopter mode of Smart UAV. © 2011 ICROS. Source


Cho A.,Smart Development Center | Kang Y.-S.,Smart Development Center | Park B.-J.,Smart Development Center | Yoo C.-S.,Smart Development Center | Koo S.-O.,Smart Development Center
International Conference on Control, Automation and Systems | Year: 2011

An intelligent tilt-rotor UAV is being developed by the Smart UAV Development Center of Korea Aerospace Research Institute. It is equipped with integrated GPS/INS system and RALT(radar altimeter) for automatic takeoff and landing. GPS/INS integration system gives the altitude referenced to WGS-84 ellipsoid which can be vulnerable to external multipath environment. RALT provides the aircraft AGL (above ground level) height with the centimeter level accuracy which is dependent on ground surface characteristics. This paper describes the simple KF (Kalman Filter) setup to integrate altitude information from GPS/INS integration system and RALT with its operational logic. It is evaluated using the data obtained from real flight tests. The result shows proposed method provides highly reliable AGL height for automatic takeoff and landing and compensates GPS/INS derived altitude drift efficiently. The proposed method can be easily applied to the existing system without modifying off-the-shelf GPS/INS integration system. It also has a small computational burden due to its simple model. © 2011 ICROS. Source

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