Abstract: In this paper a theoretical design of two degrees of freedom (single leg module) of a hexapod underwater robot is carried out. The length of the two links together is (30 cm) and the motor for the joint 2 is mounted inside the robot. In addition, forward kinematics analysis is performed to specify angle of movement for each joint by applying Denavit- Hartenberg notation. Furthermore, 3d drawings show the leg implementation. Finally, MATLAB Simulink is used to design PID controller and examine the control signal.Abstract: In this paper a theoretical design of two degrees of freedom (single leg module) of a hexapod underwater robot is carried out. The length of the two links together is (30 cm) and the motor for the joint 2 is mounted inside the robot. In addition, forward kinematics analysis is performed to specify angle of movement for each joint by applying Denavi...Show More