An Integrated Framework for Autonomous Sensor Placement With Aerial Robots

Abstract

Aerial manipulators have the unique ability to cover wide-spread areas within a single mission, making them ideal for the transport and placement of sensors required to develop an instrumented environment. Recent work in the field has focused on controllers for aerial interaction that account for compliance during contact-based tasks, omitting integration concerns that are critical to an automated sensor placement solution. Furthermore, state-of-the-art flying base manipulators are often mechanically and computationally complex, reducing their efficiency and practicality. Within this work, we present an interactive framework for autonomous sensor placement that incorporates both mechanical and software based compliance, optimised for use on a simple coplanar quadrotor. Under appropriate actuation and perception constraints, we detail the development of a control, perception, and motion planning strategy to enable automated sensor placement that relies solely on onboard computation and sensing, thus presenting a fully contained and accessible sensor placement approach capable of robust interaction with the environment. An extended finite-state machine is developed to facilitate automated mission planning.Extensive flight experiments are performed to validate the effectiveness of each sub-system, as well as the integrated solution. Experiments result in trajectory tracking errors under 10 mm as well as onboard mass estimation errors under 0.7 % for sensors of various weights. A statistical analysis of 162 flight experiments shows the proposed framework's ability to autonomously place sensors within 10 cm of the target with a success rate of 93.8 % and 95 % confidence interval of (89 %, 97 %), thus confirming the robustness and repeatability of our approach. A video showcasing our implemented solution can be found here: https://youtu.be/4R8DhVpEbSQ.

Online Search-Based Collision-Inclusive Motion Planning and Control for Impact-Resilient Mobile Robots

“…A nonlinear disturbance observer has been proposed to estimate contact force [24]. Recently, the feasibility of using cameras to estimate contact force was shown [25]. Yet, external force estimation in presence of compliant frames is an open task for aerial robots.…”

“…Bartelds et al [1] studied a compliant manipulator for impact reduction. Flying robots with end-effectors are utilized to apply a force to vertical walls [26,27], inspection [28] and sensor placement [25]. Alejandro et al [29] developed a compliant arm to monitor and control interaction wrench.…”

“…Our design differs from works [1,25] in its capacity to enable stabilization from high-speed collisions with large impact, and estimate contact forces in presence of frame compliance. The robot chassis is shared with our prior work [34] and consists of custom carbon fiber frames, a flight controller (Pixhawk), and an ARM-based multi-core processor (Odroid).…”

An Aerial Parallel Manipulator With Shared Compliance

“…1) Admittance Control: In our previous work [30], interactive capabilities were manifest via an admittance-based control scheme at the translational layer of the aerial base's dynamics, allowing for an intuitive response to an estimated external force perturbation fe ∈ R 3 . The resulting moment estimate about the vehicle's CoM, τe ∈ R 3 can be calculated using the relation from eq.…”

A Perching and Tilting Aerial Robot for Precise and Versatile Power Tool Work on Vertical Walls

“…Actuation complexity and weight reduce significantly by enabling the robot to attach itself to vertical walls and reuse rotor thrust for tilting and tool feed. The power tool tightly integrates [12] 2 N 3 mm (N=3) ---In-flight drilling Tool tip quadcopter [13] 4 N -0.8 m 0.15 kg 1.9 kg In-flight Sensors Tool tip hexacopter [14] 5 N -0.6 m -…”