1. Department of Control and Computer Engineering, Politecnico di Torino, 10129 Turin, Italy;
2. ICT for City Logistics and Enterprises Laboratory, Politecnico di Torino, 10129 Turin, Italy;
3. Polito Interdepartmental Centre for Service Robotics, Politecnico di Torino, 10129 Turin, Italy;
4. Department of Information Engineering, University of Brescia, 25123 Brescia, Italy