Multibody Syst Dyn DOI 10.1007/s11044-012-9309-8 Dynamic analysis of planar multi-body systems with LuGre friction at differently located revolute clearance joints Onesmus Muvengei · John Kihiu · Bernard Ikua Received: 26 September 2011 / Accepted: 8 February 2012 © Springer Science+Business Media B.V. 2012 Abstract In this paper, the dynamic response of a planar rigid multi-body system with stick–slip friction in revolute clearance joints is studied. LuGre friction law is proposed to model the stick–slip friction at the revolute clearance joints. This is because using this law, one can capture the variation of the friction force with slip velocity, thus making it suitable for studies involving stick–slip motions. The effective coefficient of friction is represented as a function of the relative tangential velocity of the contacting bodies, that is, the journal and the bearing, and an internal state. In LuGre friction model, the internal state is considered to be the average bristle deflection of the contacting bodies. By applying the LuGre friction law on a typical slider–crank mechanism, the friction force in the revolute joint having clearance is seen not to have a discontinuity at zero slip velocity throughout the simulation unlike in static friction models. In addition, LuGre model was observed to capture the Stribeck effect which is a phenomenon associated directly with stick–slip friction. The friction forces are seen to increase with increase in input speed. The effect of stick–slip friction on the overall dynamic behavior of a mechanical system at different speeds was seen to vary from one clearance joint to another. Keywords Dynamic response · LuGre friction model · Multi-body system · Revolute clearance joint · Stick–slip friction 1 Introduction The dynamic modeling of multi-body systems has been recognized as a key aid in the anal- ysis, design, optimization, control, and simulation of mechanisms and manipulators. How- ever, clearance, friction, impact and other phenomena associated with real joints have been routinely ignored in order to simplify the dynamic model. The increasing requirement for high-speed and precise machines, mechanisms and manipulators demands that the kinematic O. Muvengei ( ) · J. Kihiu · B. Ikua Department of Mechanical Engineering, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya e-mail: ommuvengei@gmail.com