Development of Simple Rehabilitation Device Using Flexible Linear Stepping Actuators

The Use of Generative Design Methods to Reduce the Parameters of an Actuator Used in the Positioning System of a Continuous Passive Motion (CPM) Device

“…Figure 2 shows the kinematic structure of the single-limb positioner. (9); (e) adding a mass points loading of the thigh, calf, and foot supports to model the impact of the patient's lower limb at points of direct contact with the CPM device positioning system (7), (8), and (10).…”

“…A summary of the masses of each joint and element is highlighted in Figure 1 and an indication of the material of manufacture of the joints is given in Table 1. (9); (e) adding a mass points loading of the thigh, calf, and foot supports to model the impact of the patient's lower limb at points of direct contact with the CPM device positioning system (7), (8), and (10).…”

“…The CPM has two independently controlled platforms, mainly used to support the patient's feet (7) during the movement of the main positioners. Structurally, the kinematic chain is formed by a calf support yoke (6), which forms a fixed platform, the aforementioned movable lower foot support platform and three electric linear actuators (8), which are coupled to the platform via rotary joints, thus forming a parallel tripod robot structure. The working position of the mobile platform can be either permanently fixed during the entire movement of the main positioner or dynamically changed during the movement.…”

“…Various modifications of the CPM device are being used in many research centres around the world for mechanical kinesitherapy of various human upper and lower limb joints [6][7][8]. The Department of Automatic Control and Robotics at the Bialystok University of Technology, Poland has also developed a similar device for rehabilitation after arthroscopy and knee arthroplasty [9,10].…”

“…We can distinguish between them: (a) links (1), (2), and (3) form the articulated quadrilateral mechanism; (b) links (3), (4), and (6), form the crank-slider mechanism; (c) (5) indicates the fixed attachment to the device frame forming a rotating kinematic pair with link (3); (d) (6) is the translational car of the linear guide, and forms a rotating kinematic pair with link (4); (e) (11) is the Delta robot articulated joint connecting the electric actuators to the patient's foot support platform (10), via spherical joints; (f) (12) is the linear guide track. Major changes to the geometry from the original 3D virtual model in SolidWorks include (a) removal of any chamfers and small holes for connectors; (b) removal of the screws connecting the kinematic chain components; (c) removal of bearings and shafts from rotating pairs; (d) replacing the mass of individual electric linear actuators by masses concentrated at a point, to obtain a representation of the real mass of a commercial solution (9); (e) adding a mass points loading of the thigh, calf, and foot supports to model the impact of the patient's lower limb at points of direct contact with the CPM device positioning system (7),(8), and(10).A summary of the masses of each joint and element is highlighted in Figure1and an indication of the material of manufacture of the joints is given in Table1.…”