Analysis of the robotic peg-hole insertion

In the heavily studied precise robotic peg-hole insertion (clearances of about 0.02 mm) operation, there are two primary methods to reduce the lateral and angular errors which are caused when a peg is controlled to approach a hole. The active approach uses a feedback signal to obtain the fine control over peg position. The passive approach uses RCC to enable insertion through resilient action under the influence of contact forces. A strategy for the peg-hole insertion with defined initial conditions and without using force sensors and RCC is proposed. This combines the principles of both active and passive techniques. The major features of this strategy are that it: (1) requires no force sensors, (2) works without RCC (remote centre compliance), (3) operates with very small clearances, (4) provides minimum process time, (5) operates reliably. An experiment with a peg diameter of 31.99 mm and hole clearance of 0.02 mm was used to verify the strategy. This confirmed the potentially wide application in industry where its simplicity can be fully exploited.