*2.6. Assistive Robotic Devices*

The system is able to integrate two different types of robotic devices to assist people with disabilities: (i) an external robotic arm; or (ii) a robotic exoskeleton. Both of them mounted are on the robotized wheelchair.

The control architecture of the robot is independent of the type of robot used as an assistive device. This architecture was implemented in a low layer and a high layer. The low layer implements the low-level control of the robotic device. It implements a joint trajectory controller, which executes the trajectories received by the high-level controller. The other layer corresponds to the high-level controller, which is responsible for managing the communication of the robot with the system, but it also implements a motion planning system. This motion planning system resorts to the learning by demonstration (LbD) method based on the dynamic movement primitives (DMPs) proposed and evaluated in [21].

#### 2.6.1. Exoskeleton Robotic Device

An upper limb exoskeleton was designed with five active degrees of freedom corresponding to the following arm movements: shoulder abduction/adduction, shoulder flexion/extension, shoulder internal/external rotation, elbow flexion/extension, and wrist pronation/supination [11,12,21,22]. This device allows the user's right arm to be moved to reach objects, thus facilitating the performance of ADLs (Figure 1).

In addition to the arm exoskeleton, an active hand exoskeleton was designed to assist the opening and closing of the right/left hand [23,24]. It consists of four independent modules anchored to a hand orthosis that actuate the movements of the thumb, index finger, and middle finger, and jointly move the ring and little finger. The configuration of the hand can be adapted according to the size of the hand.

#### 2.6.2. Robotic Manipulator

The system can also integrate an external robotic manipulator. Experimental tests of the complete system were carried out with JACO robot produced by Kinova (Boisbriand, Canada) [25]. This robotic manipulator is a very light manipulator (4.4 kg for the arm and 727 g for the hand), which can be installed on a motorized wheelchair (right or left) to help people with upper extremity mobility limitations. It has seven degrees of freedom, with a two- or three-finger gripper with a maximum opening of 17.5 cm. The JACO robot is capable of loading objects from 3.5 kg to 4.4 kg, being able to reach objects within a radius of 75 cm.

#### *2.7. Processing and Control System*

The system has two computers, the main computer of the system and the computer integrated within the mobile robotic platform (Figures 1 and 4).

The computer of the mobile robotic platform executes the navigation algorithms of the mobile platform using all the information from the sensors. It communicates with the main computer to execute the actions received from the system, as well as to inform the system about the current state during the navigation.

The main computer performs the communication between all the components of the system, processes all the information gathered from the sensors and cameras, and controls the arm and hand exoskeletons. This computer has its own 91 kWh battery.

Both computers communicate through a WiFi router. In this way, we can monitor the operation of the entire system by connecting an external computer to the router.

**Figure 4.** Diagram with the connections between all the components of the platform.
