Two-Layers Workspace: A New Approach to Cooperative Object Transportation With Obstacle Avoidance for Multi-Robot System. - Stephanie Kamarry Alves De Sousa; Raimundo Carlos Silvério Freire; Elyson Adan Nunes Carvalho; Lucas Molina; Phillipe Cardoso Santos; Eduardo Oliveira Freire (IEEE Access, 2022)