Fig 1.
3 DoF Robotic Platform (A) In the solid model, the main components of the system are presented (B) The first prototype of the design is presented.
Fig 2.
(A) The motions of human ankle joint (B) The robotic platform in static condition (C) Rotational motion in roll direction (D) Rotational motion in pitch direction (E) Linear motion in z direction.
Table 1.
Average foot-pad pressure ratios [55].
Fig 3.
Upper and lower platforms (A) In the solid model, the components and their positioning on the upper platform are demonstrated (B) In the solid model, the components and their positioning on the lower platform are demonstrated (C) Top view of the prototype of the upper platform (D) Top view of the prototype of the lower platform.
Table 2.
Fig 4.
(A) Illustration of the ready-to-use system configuration (B) Virtual reality environment.
Fig 5.
Schematic representation of 3 DoF parallel manipulator.
Fig 6.
(A) Geometric constraints (B) Vector loops for the kinematic and dynamic analyses (C) Linear actuator link variables.
Fig 7.
The flowchart of the simulation.
Table 3.
Dimensions of 3-DoF parallel manipulator, LA*: LinearActuator.
Fig 8.
Simulation results (A) Translational motion of the end-effector (B) Rotational motion of the end-effector.
Fig 9.
Von Mises result under the static nodal stress for (A) Upper platform, (B) Lower platform, and (C) Linear actuator.
Fig 10.
(A) Adams Model, and Required linear actuator force (B) in z translation and (C) in 200 angle.
Fig 11.
Experimental verification of system performance (A) Real-time control architecture (B) Response of each actuator to a step reference (C) Response of each actuator to a sinusoidal reference.
Fig 12.
Experimental procedure for the evaluation of upper platform in the static condition (A) Two water-filled jars are distributed over the upper platform (B) Pressure distribution of the distributed load on the left side of the platform only (Case 1a: standing on the left foot scenario), and right side only (Case 1b: standing on the right foot scenario) (C) Pressure distribution on the front half of the platform (Case 2: standing forefoot scenario) (D) Pressure distribution on the rear half of the platform (Case 3: standing on the rearfoot scenario) (E) Pressure distribution evaluation test statistics.
Table 4.
Experimental evaluation of the upper platform under static condition.
Fig 13.
Experimental evaluation of the upper and lower platforms under dynamic condition (A) Pressure distribution of the payloads while the end-effector is in anthropomorphic motion (B) Variation of CoM of payloads while the end-effector is in anthropomorphic motion.
Table 5.
Experimental evaluation of the upper platform under dynamic condition.