Conference Paper

New Design of the Steering Mechanism for a Mini Coaxial Helicopter

Autonomous Syst. Lab., ETH Zurich, Zurich
DOI: 10.1109/IROS.2008.4650769 Conference: 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, September 22-26, 2008, Acropolis Convention Center, Nice, France
Source: DBLP


Whenever the realization of a swash plate mechanism is not feasible (e.g. due to miniaturization limitations), center of gravity steering is an interesting alternative to swash plate steering. We present an approach to describe the dynamic behavior of a coaxial micro helicopter steered by a center of gravity shifting mechanism. The mechanical design of an existing system is improved to increase mechanical robustness and steering quality. In parallel, a simulation model is developed and implemented. It is used to estimate the system response to steering inputs, and to compare center of gravity to swash plate steering. Experimental flight results show an improvement of the helicopter performance due to the mechanical redesign.

80 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper shows roll and pitch feedback control on a coax-ial mini helicopter equipped with a center of gravity steering mechanism. The helicopter carries a minimal set of sensors to measure yaw rate, dis-tance to ground and roll and pitch angle. While yaw rate and distance to ground control are already realized on the helicopter, roll and pitch control including the necessary signal filtering are newly developed for the system. Additionally, two feedforward compensations for the distance to ground control are introduced. Flight data shows the performance of the attitude control subjected to external disturbances, and the improve-ments achieved by the two compensations in distance to ground control.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the control and mechanism of a flying robot that uses a coaxial double contra-rotation rotor. The flying robot consists of two rotors, landing legs, and a body. There are three motors: two motors are employed to control two rotors, and the other motor is used to control the center of gravity. In addition, an ultrasonic range sensor is installed under the body to measure flight height, and a gyro sensor is attached at the body to measure the direction of the rotation of the body. The rotational speed of the rotors is controlled by a PWM controller with programmable duty cycle. Through hovering flight experiments, the effectiveness of the mechanism and the control system of the flying robot is verified.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new hybrid micro vehicle, called the Hopping Rotochute, was developed to robustly explore environments with rough terrain while minimizing energy consumption over extended periods of time. Unlike traditional robots, the Hopping Rotochute maneuvers through complex terrain by hopping over or through impeding obstacles. A small coaxial rotor system provides the necessary lift while a movable internal mass controls the direction of travel. In addition, the low mass center and egg-like shaped body creates a means to passively reorient the vehicle to an upright attitude when in ground contact while protecting the rotating components. The design, fabrication, and testing of a radio-controlled Hopping Rotochute prototype as well as an analytical study of the flight performance are documented. The aerodynamic, mechanical, and electrical design of the prototype is outlined which were driven by the operational requirements assigned to the vehicle. The aerodynamic characteristics of the rotor system as well as the damping characteristics of the foam base are given based on experimental results using a rotor test stand and a drop test stand respectively. Experimental flight testing results using the prototype are outlined which demonstrate that all design and operational requirements are satisfied. A dynamic model associated with the Hopping Rotochute is then developed including a soft contact model which estimates the forces and moments on the vehicle during ground contact. A comparison between the vehicle's motion measured using a motion capture system and the simulation results are presented to determine the validity of the experimentally-tuned dynamic model. Using this validated simulation model, key parameters such as system weight, rotor speed profile, internal mass weight and location, as well as battery capacity are varied to explore the flight performance characteristics. The sensitivity of the hopping rotochute to atmospheric winds is also investigated as well as the ability of the device to perform trajectory shaping. Ph.D. Committee Chair: Costello, Mark
Show more