Rotorcraft collision avoidance using spherical image-based visual servoing and single point features

This paper presents a reactive collision avoidance method for small unmanned rotorcraft using spherical image-based visual servoing. Only a single point feature is used to guide the aircraft in a safe spiral like trajectory around the target, whilst a spherical camera model ensures the target always remains visible. A decision strategy to stop the avoidance control is derived based on the properties of spiral like motion, and the effect of accurate range measurements on the control scheme is discussed. We show that using a poor range estimate does not significantly degrade the collision avoidance performance, thus relaxing the need for accurate range measurements. We present simulated and experimental results using a small quad rotor to validate the approach.

Authors

• Aaron McFadyen
• Peter Corke
• Luis Mejías

Keywords

• Cameras
• Azimuth
• Aircraft
• Spirals
• Collision avoidance
• Optical imaging
• Single Feature
• Feature Points
• Visual Servoing
• Spherical Features
• Image-based Visual Servoing
• Single Point Feature
• Control Strategy
• Range Of Estimates
• Spiral Trajectory
• Degrees Of Freedom
• Field Of View
• Image Features
• Optimal Control
• Azimuth Angle
• Stopping Criterion
• Optical Flow
• Vertical Displacement
• Spherical Surface
• Difficult Cases
• Visual Control
• Forward Velocity
• Translational Velocity
• True Range
• Velocity Commands
• Inertial Frame
• Different Degrees Of Freedom
• Spherical Image
• Vertical Control
• Yaw Rate
• Angular Measurements