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portfolio
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publications
A comparative study between a cant angle hexacopter and a conventional hexacopter
Published in International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), 2016
The purpose of this paper is to present a brief comparison between a conventional hexacopter and a cant angle hexacopter. A conventional hexacopter has got all its 6 rotors fixed and thrusted upwards in the body frame which gives it a decoupled 4 DOF motion or a coupled 6 DOF motion. But a cant angle hexacopter has all its six rotors canted at an angle tangentially to the radius of the frame. It provides 2 extra degree of freedom in the translational X & Y axis without any coupling. A conventional hexacopter cannot translate in X & Y axis without tilting but the cant angle hexacopter serves this purpose. In this paper we compare their dynamic models using classical Newton Euler equations and design a PD controller for simulating the vehicle dynamics.
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Static performance analysis of electric propulsion system in quadrotors
Published in International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), 2016
This paper describes the selection of brushless motors, propellers and battery for getting maximum time of hover for a quadrotor UAV. We also introduce a experimental testbed to measure various parameters of the system like torque, thrust, RPM, current and voltage. The static testbed is directly interfaced through MATLAB for real time data acquisition. We tested different motor and propeller combinations to find the relation of their various parameters with efficiency and static coefficients.
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Experimental Implementation of Fuzzy Vision-Based Tracking Control of Quad-Rotor
Published in Soft Computing Applications: Proceedings of the 7th International Workshop Soft Computing Applications, 2017
This paper presents a novel approach to detect and track an object using a quadrotor-UAV. The proposed system mainly consists of two parts- (i) Object detection and tracking using histogram backprojection and CAMSHIFT tracker, (ii) Fuzzy Proportional and Fuzzy Proportional-Derivative controller for controlling the drone. We implemented our algorithm using ROS (Robot Operating System), OPENCV library and MATLAB programming environment.
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Bio-inspired Landing of Quadrotor using Improved State Estimation
Published in IFAC-PapersOnLine, 2018
This paper presents an improved state estimation technique - a fusion of Monocular SLAM (Simultaneous Localization and Mapping) and INS (Inertial Navigation System). It is utilized in landing a commercially available low cost quadrotor (Parrot AR Drone 2.0) in indoor environments along a trajectory generated by a bio-inspired guidance method. The method is based on Tau theory and facilitates safe and smooth landing of UAVs by closing motion gaps with zero relative velocity and acceleration. A depth camera (Microsoft Kinect) provides a helping hand in very accurate landing towards the end of the quadrotor’s trajectory. A dynamic inversion based controller is designed which works as a outer loop controller for the quadrotor.
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Dynamic inversion control of quadrotor with a suspended load
Published in IFAC-PapersOnLine, 2018
In this paper, I have tackled the problem of a quadrotor with a suspended load using nonlinear dynamic inversion method. The main purpose of this paper is to present a new dynamics of the UAV-load system using Newton’s law. I applied dynamic inversion control for directing the UAV to the desired coordinates and simultaneously minimizing the sway angle of the suspended mass. I have carried the entire simulation in the inertial frame. My approach is to use an outer loop controller for maintaining the position and an inner loop controller for the desired roll, pitch and yaw rate. I have performed the simulations on MATLAB.
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Incremental Nonlinear Dynamic Inversion Control of Long-Stroke Pneumatic Actuators
Published in European Control Conference (ECC), 2021
Pneumatic cylinders provide an environment-friendly actuation means by minimizing the leakage of any harmful industrial fluids, as occurs for hydraulic actuators. However, pneumatic actuation has not been utilized widely for industrial servo applications due to its highly nonlinear nature. Incremental nonlinear dynamic inversion (INDI) is a form of nonlinear dynamic inversion (NDI) that relies less on plant-model information, and is thus inherently robust to mismatches in the known plant-model, and also to external disturbances. Developing an incremental nonlinear controller for a pneumatic system is the main focus of this research article, which is accomplished by utilizing a cascaded-control approach, where the inner-loop INDI tracks a given force and the outer-loop NDI is for controlling the piston-position. Moreover, realistic sensor noises have been added in the simulation and the robustness of the incremental approach is demonstrated with respect to a baseline PID controller.
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Motor-level N-MPC for cooperative active perception with multiple heterogeneous UAVs
Published in IEEE Robotics and Automation Letters , 2022
This letter introduces a cooperative control framework based on Nonlinear Model Predictive Control (NMPC) for solving an Active Information Acquisition problem (AIA) using a system of multiple multirotor UAVs equipped with onboard sensors. The observation task of the NMPC is a minimum-uncertainty pose estimation of a moving feature which is observed by the multi-UAV system, using a cooperative Kalman filter. The controller considers a full nonlinear model of the multirotors – including the motor-level actuation units and their real constraints in terms of maximum torque – and embeds the Kalman filter estimation uncertainty in its prediction. The framework allows and exploits heterogeneity in the actuation and sensing systems by considering a generic model of UAV – including both quadrotors and tilted-propeller multirotors – and a generic model of range-and-bearing sensor with arbitrary rate and field of view. The capability of the proposed framework to reduce the cooperative estimation uncertainty of a static or a moving feature, thus leading the system to optimal sensing configurations, is demonstrated through Gazebo simulations and real experiments. The software is provided open-source.
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Nonlinear model predictive control for human-robot handover with application to the aerial case
Published in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2022
In this article, we consider the problem of delivering an object to a human coworker by means of an aerial robot (AR). To this aim, we present an ergonomics-aware Nonlinear Model Predictive Control (NMPC) designed to autonomously perform the handover. The method is general enough to be applied to any multi-rotor aerial vehicle (MRAV) with a minimal adaptation of the robot model. The formulation of the optimal control problem steers the AR toward a handover location by optimizing the human coworker ergonomics, which includes the predicted arm joint torques of the human. The motion task is expressed in a frame relative to the human, whose motion model is included in the equations of the NMPC. This allows the controller to promptly adapt to the human movements by predicting her future poses over the horizon. The control framework also accounts for the problem of maintaining visibility on the human coworker, while respecting both the actuation and state limits of the robot. Additionally, a safety barrier is embedded in the controller to avoid any risk of collision with the human partner. Realistic simulations are performed to validate the feasibility of the approach and the source code of the implementation is released open-source.
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Hardware-in-the-Loop Simulation of Vehicle-Manipulator Systems for Physical Interaction Tasks
Published in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2023
Hardware-in-the-loop simulation (HILS) allows a more realistic evaluation of control approaches than what is possible with pure software simulations, but without the actual complexity of the complete system. This is important for some complex systems such as orbital robots, where testing of the system is typically not possible after its launch, and an on-ground replica is used to validate the performance of such a system. In this article, an impedance-matching approach is presented to match the end-effector dynamics of a fixed-base robot manipulator with that of a target vehicle-manipulator system (VMS), while taking into account the redundant nullspace dynamics in a connected real-time simulation framework. This approach ensures that the forces and torques exerted by the system on the environment matches with that of the simulated system. The contact wrenches used in our approach are not obtained from numerical simulations, but rather from real physical interaction, which is one of the main advantages of our approach. The effectiveness of our method is validated by demonstrating various physical interaction tasks with the environment, using a suspended aerial manipulator as the target system.
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Observer-based Controller Design for Oscillation Damping of a Novel Suspended Underactuated Aerial Platform
Published in (To Appear) IEEE International Conference on Robotics and Automation (ICRA), 2024
In this work, we present a novel actuation strategy for a suspended aerial platform. By utilizing an underactuation approach, we demonstrate the successful oscillation damping of the proposed platform, modeled as a spherical double pendulum. A state estimator is designed in order to obtain the deflection angles of the platform, which uses only onboard IMU measurements. The state estimator is an extended Kalman filter (EKF) with intermittent measurements obtained at different frequencies. An optimal state feedback controller and a PD+ controller are designed in order to dampen the oscillations of the platform in the joint space and task space respectively. The proposed underactuated platform is found to be more energy-efficient than an omnidirectional platform and requires fewer actuators. The effectiveness of our proposed system is validated using both simulations and experimental studies
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talks
Talk 1 on Relevant Topic in Your Field
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Conference Proceeding talk 3 on Relevant Topic in Your Field
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teaching
Teaching experience 1
Undergraduate course, University 1, Department, 2014
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Teaching experience 2
Workshop, University 1, Department, 2015
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