Modulation of Joint Stiffness for Controlling the Cartesian Stiffness of a 2-DOF Planar Robotic Arm for Rehabilitation. - Thanapol Tantagunninat; Narakorn Wongkaewcharoen; Khemwutta Pornpipatsakul; Rada Chuengpichanwanich; Ronnapee Chaichaowarat (AIM, 2023)