Robot walking ?

Hi



Today I’m facing not problem with blender but the robot walking cycle. I tried to do my best to make it good but i failed. The cycle is not good at all. Please check the file, tell me if there is something wrong or missing, and if you have time please make it for me.

Robot file
https://www.sendspace.com/file/lds24z

I don’t really have time to make you a better animation, but I think if you learn about IK (inverse kinematics) constraints, you may be able to solve your own problem.