Centralized Control of Multirotors with Manipulators
Multirotors with manipulator arms are multibody systems whose mass characteristics (position of center of mass and moments of inertia) change with time when the arms move and bear reaction torques generated by the arm servos. This chapter presents a contr
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Abstract Multirotors with manipulator arms are multibody systems whose mass characteristics (position of center of mass and moments of inertia) change with time when the arms move and bear reaction torques generated by the arm servos. This chapter presents a control system for aerial manipulators based on integral backstepping that estimates all these effects to effectively stabilize the rotational dynamics of the aerial robot. Validation experiments are also presented in the chapter.
1 Introduction Most controllers for standard multirotor configurations are based on the assumptions that the aerial vehicle is modeled as a rigid body to which the forces and torques generated by the actuators are applied, and the center of mass (COM) is located at the central axis of symmetry of the multirotor. Multirotors with manipulator arms are in turn multibody systems whose dynamics present significant differences with standard multirotors: the moments of inertia and the COM position change when the arms move, the torques generated by the arms joint actuators are transmitted to the multirotor frame and the contact forces and torques of the end effectors are also transmitted to the multirotor. This chapter presents the control system of aerial manipulators based on integral backstepping that estimates all these effects to effectively stabilize the rotational dynamics of the aerial robot.
A. Jimenez-Cano (B) · G. Heredia · A. Ollero GRVC Robotics Lab Sevilla, Universidad de Sevilla, Seville, Spain e-mail: [email protected] G. Heredia e-mail: [email protected] A. Ollero e-mail: [email protected] © Springer Nature Switzerland AG 2019 A. Ollero and B. Siciliano (eds.), Aerial Robotic Manipulation, Springer Tracts in Advanced Robotics 129, https://doi.org/10.1007/978-3-030-12945-3_8
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2 Modelling A problem that arises in aerial manipulation is that the dynamic behavior of the vehicle changes due to the modification of the mass distribution and dynamics by grasping and manipulating objects. The main effects that appear and make the dynamic behavior of the aerial vehicle with a manipulator different from the standard configuration, such as displacement of the center of mass from the vertical axis at the geometrical center of the vehicle, variation of mass distribution or the dynamic reaction forces and torques generated by the movement of the arm. These effects are not usually taken into account explicitly in conventional controllers, and are left to the integral term in the feedback controller for correction. The effects of the displacement of the center of mass in a helicopter with a manipulator arm will be analyzed in chapter ‘Centralized Control of Helicopters with Manipulators’. This chapter presents a Variable Parameter Integral Backstepping (VPIB) controller for a multicopter with a manipulator arm. A preliminary version which took into account the first two points (variation of center of mass and moments of inertia with the movement of the arm), but did not consider the third one (dynamic reaction t
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