The causes of failure of stabilising a triple link inverted pendulum using only one control input are investigated and mostly determined. In addition to using computer software in deriving and simulating the dynamics of a triple link inverted pendulum system, experimental observations and measurement improvements play major roles in the iterative control system design process. Stick friction, measurement noise and speed of third link are found to be the most decisive factors in stabilising this system. The experience, learned from earlier experimental success, of stabilising a double link inverted pendulum is used to modify the system＇s model. this becomes part of a single input state space control law which is capable of stabilising the triple link inverted pendulum system about its upright position. This control input is realised in experiments through the use of a DC motor driven by a microcomputer.