Last night, I implemented a simple 6 step ripple gait, which I will explain in a minute. Let me explain what’s the problem I discovered first with the IK algorithm. When the legs are meant to move along Z axis, the front and rear legs are actually moving toward Z-X direction, which is not right. So I wrote a test program to test the leg IK algorithm by checking the actually physical change of the leg position, versus the coordinate I entered manually. Again the legs won’t move solely along one particular axis (X or Z), but tend to go somewhere in between. Spent an evening thinking about it, realize the original idea of calculation IK isn’t perfect for my type of Arduino Hexapod Robot, which each leg are in a different frame (frame – Axis system), but I have always been assuming they are in the same frame as the center of body. for example, the frame of the front right leg is rotated -30 degree from the frame of the center of body (see below picture), so before we calculate the change of angles from leg IK algorithm, we need to do coordinate transformation first, to convert it from body frame to the coxa frame. A common way would be using rotation matrix. detail please go to my IK implementation post. after the modification, the robot can finally walk like one. ; )