Dynamics and Control of Robotic Manipulators with Contact and Friction

1Introduction

1.1 Robot Joint Friction Modeling and Parameter Identification

Robot design generally considers only the ideal circumstances. The actual robot experiences great differences from the model built and simulated with MATLAB or other graphical tools, with manufacturing errors, friction, and gravity contributing the most to these differences [1]. There are also complex nonlinear problems [2]. With the wide application of robots in different industries involving humans, the demands of safety, accuracy, and reliability on robots is continually increasing. Contact and friction always influence the accuracy and reliability of the robot. For a more reliable and accurate solid robot, the design – especially control design – must account for friction, contact, and impact, as well as friction in the force feedback mechanism.

In recent decades, industries and academia have conducted research and developed related to robotic dynamics and control. In recent years, some have focused on the contact and friction generated in robot joints during movement [3–8]. There have been different methods presented to build an accurate model of joint friction based on experimentation and analysis of the corresponding results. Nonlinear characteristics of friction [9–15] are obvious, especially in the low‐speed motion of robot, so nonlinear dynamics of robot must be considered as well.

Friction is a tangential resistant force to sliding in a dynamic system. To investigate friction, it is necessary ...