Control framework for cooperative object transportation by two humanoid robots

Abstract

This paper aims at proposing a comprehensive control framework designed for cooperative transportation of a heavy load by two humanoid robots. First, a simplified dynamic model of the cooperative task is developed and the system stability is rigorously analyzed. Next, a centralized controller is formulated, this formulation provides an optimal control of the system by considering the robots dynamical stability while satisfying the robot-object-robot constraints. Finally, the controller is integrated with an arm controller and a local planner module forming a complete framework for cooperative transportation tasks. The approach is thoroughly analyzed and validated in simulation, and experiments are carried out on a team of two Nao humanoid robots transporting a range of objects placed on a small table. The experimental results pointed out the robustness of the approach as the robots successfully accomplished the transportation tasks in a stable way, moreover the transported objects masses were up to half the mass of one of the robot. Besides increasing the robot payload, some of the transported objects are relatively large and it is simply impossible for a single robot to transport them.

Walking Human Trajectory Models and Their Application to Humanoid Robot Locomotion

“…In [4] a controller is proposed to control two Nao humanoid robots in order to move collaboratively a table from one place to another. The controller stability is analyzed and proved to be stable.…”

“…Following such dynamics is not simple as it depends on the mechanical capabilities of the robot, its stabilizer, its walking pattern generator and the used foot step planners as shown in [4]. We therefore choose to use the stabilizer and the walking pattern generator provided by PAL Robotics on the humanoid robot TALOS.…”

External Force Observer for Small- and Medium-Sized Humanoid Robots

“…The first component of the external force applied to the humanoid robot that can be directly estimated from the FSR information is F z using (5). Then the horizontal components F x and F y can be estimated using (7).…”

“…As an example, the transportation of a heavy object on a rolling cart, as depicted in [2,3], can be greatly improved if the external force generated by the cart and the transported object can be accurately measured or estimated. Moreover, for a cooperative transportation task of an object with two humanoid robots [4,5] or with a humanoid robot and a human [6], it is crucial to measure the force exchanged through the transported object in order to maintain the equilibrium of the whole system. In this paper, we consider the case of an external force applied to the humanoid robot as illustrated in Fig.…”

Humanoid Robot Cooperative Motion Control Based on Optimal Parameterization

“…And this method independently identifies the inertial parameters of each connecting rod assembly with the high precision of parameter identification. Hawley and Suleiman ( 2019 ) proposed a complex integrated control framework consisting of a centralized controller, an arm controller, and a ZMP preview controller. However, this method simplifies the coupling force in the collaboration to an external force, making it difficult to accurately measure the essential physical parameters during the motion process.…”