# A Prototype Mechatronic Device for Upper Limb Rehabilitation and Analysis of Its Functionality
## 3 Concept and Design Solution for the Rehabilitation Device
### Concept  
The primary objective of the project was to develop a mechatronic device for upper limb rehabilitation that enables the user--typically a patient--to perform dedicated tasks displayed on a screen. These tasks involve repositioning objects (blocks) into designated containers.  
A conceptual diagram of the rehabilitation device is shown in Figure 1. The device is primarily intended for individuals requiring intensive, active upper limb exercises, which may involve both arms simultaneously or each arm individually, depending on the rehabilitation therapist's recommendation. The design prioritises repetitive movement across the entire upper limb, including the wrist and fingers.  
The rehabilitation device consists of a base (Figure 1b) on which three drive modules are mounted in a linear configuration. These drive modules are positioned to face the user. Each drive module is connected to an arm: two lateral arms (left and right; see Figure 1a) constitute the task modules, while the central arm comprises the storage module. An electric motor is mounted at the end of the central arm, with a storage container affixed to its shaft. This container is open at the top and features primary vertical walls, along with removable secondary walls.  
The central arm is mounted lower than the side arms to avoid any interference during movement. It consists of two telescopically connected profiles with adjustable locking holes, allowing the arm length to be customised and secured. Similarly, each task arm is equipped with an electric motor at its end, which drives a rotating task container mounted on the motor shaft. Each task container features a plate with rounded edges and three smaller containers mounted on its upper surface (these may be designed as separate containers set into recesses on the plate).  
In the initial setup, two of the three containers in each task module are positioned closer to the user, while the third is farthest away, nearer the display. Each container recess is fitted with a pressure sensor that detects when an object has been correctly placed. Additional control buttons will be located between the containers and on the front edge of the plate; these will be used in advanced training stages to allow manual confirmation of the task's completion.  
Each task container will also be equipped with colour sensors located in grooves at the front edge of the base and on the side facing the storage module. These sensors are installed on the inner vertical walls of the containers and are used to detect the colour of the inserted objects. RGB LED indicators are included to signal correct object placement in the designated container sections.  
The base plate, which holds the containers, is designed with a curvature radius that is smaller on the side nearest the two containers and larger on the side facing the display. Task containers are fitted with interchangeable covers featuring specific cut-out shapes. These flat covers, mounted individually, include through-holes that allow objects to be inserted into the containers below.  
To ensure effective user interaction and ease of operation for staff, the device includes a touchscreen LCD display. Control of and interaction with the device will be facilitated via a graphical user interface. The screen is mounted on an adjustable arm, allowing its position and tilt angle to be modified according to individual user needs. The control module is integrated into the base of the device in a way that does not obstruct the user or medical personnel.  
Figure 1: Rehabilitation device for the hand with its key components: (**a**) basic projection of the arm system, (**b**) isometric projection with left, right, and storage containers. 1—base, 2—display, 3—task container, 4—storage container, 4a—primary wall, 4b—secondary wall, 5a—central arm, 5b—side arm, 6—electric motor, 7—extension, 8—groove, 9—limit pressure sensor, 10—control button, 11—colour sensor, 12—attachment, 13—through-holes, 14—blocks, 15—LED, 16—socket, A—left container module, B—right container module.