We present the design of the Turmell-Bot, a configurable cable-driven robot for human ankle physical therapy.The simplest ankle model is the two-rotary serial chain known as the talocrural and subtalar axes.We focus on how the ankle tendons pull the mid-foot bones around the axes.We implemented a primary two-rotary mechanism analogous to the ankle joint.And by using the screw theory, we analyzed the interaction between anklefoot tendons and joints.Then, we synthesized a cabledriven robot that considers the human ankle serial chain in the closed-loop mechanism.We incorporated a drawwire sensor to measure the axes' position and orientation.Using axis projection on the base and platform planes, we balanced the actuators.We also computed the workspace and kinematics.Finally, we validated the robot's stability with the software MuJoCo and proposed a mechanical design.