## 2 System Architecture
### Hardware Specifications and Setup  
It is evident that the use case requirements could be met by any mobile manipulator endorsed with specifically designed software components. However, it is essential to briefly describe herein the RAMCIP robot physical implementation view in order to present the minimum required hardware specifications, while exhibiting how each hardware component contributed to the completion of the medication assistance scenario. To this end, the basic architectural elements of the utilized robot (see Figure 2) are described as follows:  
**Mobile Platform:** The mobile platform comprises a two degrees of freedom (DoF) differential kinematics model. It provides the locomotion functionality and hosts the entire computational system of the robot. This component is responsible for performing the navigation tasks required for approaching the human and fetching the medication box.  
**Elevation Mechanism:** The elevation mechanism allows the robot to reach both higher (around 1.75 m) and lower (e.g., floor or low table) locations with the same robotic arm. This component is essential when the medication box is stored in a high place where the robot has to be stretched in order to reach it, or has to be shrunk in order to reach a lower table.  
**Arm manipulator:** The arm manipulation is relied in an 8-DoF kinematic model offering increased operational workspace that allows the robot to grasp the medication container in various environment topologies. The 6 DoF arm operational workspace is extended when considering the fact that the manipulator is mounted on a rotary actuated turntable with an elevation mechanism. To increase safety and endorse compliance manipulation capabilities, a force torque sensor has been mounted between the arm wrist and the hand.  
**Hand:** The robot is equipped with a three-fingered robotic hand with nine degrees-of-freedom, suitable to perform grasping of different objects with various grasping strategies. It is also equipped with force sensors at its fingertips that offer situation awareness when transferring the medication box to the user.  
**Head:** The robot has a 2 DoF head equipped with a display for facial expressions that enables robot-user interaction and augments it with affective cues. The actuation of the robot head is inherited to a mounted RGB-D camera on top of it. On the one hand, the motorized head augments the robot's perception by enabling active vision and, on the other hand, it allows natural robot reaction when interacting with the user where perception along manipulation should be coordinated. Part of the communication modalities constitute a projector for the provision of augmented reality (AR) communication purposes.  
Figure 2: The basic architectural elements of the RAMCIP robot. The robotic platform with the elevation mechanism, the turntable, the arm manipulator and the head have been developed by ACCREA Engineering®. The utilized hand is the smart grasping system of SHADOW Robot Company, Ltd.®.  
**Perception System:** The robot perception system consists of a motorized RGB-D sensor mounted on the robot's head and two laser scanners mounted on the platform. The RGB-D sensor is utilized for the mapping, the environment monitoring and the human tracking. The laser scanners are utilized mainly for the robot localization and navigation and, in cases of cameras' occlusions, provide rough estimations of the user's location in the environment.  
**HR-Communication Modalities:** In the front of the robot body, interaction components are included such as microphone, tablet PC and speakers, allowing communication with the user. This module is utilized for the provision of notifications and the dialogues during medication adherence session.