Dynamics and control of a spatial rigid-flexible multibody system with multiple cylindrical clearance joints
Cheng Liu, Qiang Tian, Haiyan Hu, Mechanism and Machine Theory, June 2012, Volume 52, pp 106-129.
Abstract
The dynamics and control of a rigid-flexible multibody system with multiple cylindrical clearance joints are studied via the Absolute Coordinate Based (ACB) method that combines the Natural Coordinate Formulation (NCF) describing rigid bodies and the Absolute Nodal Coordinate Formulation (ANCF) describing flexible bodies. The spatial cylindrical joints with clearances are modeled by two rigid bodies, that is, the journal and bearing, where the difference in radius and axial directions defines the radial clearance and axial clearance, respectively. A new four-point contact kinematic model of NCF is proposed for the rigid cylindrical clearance joint. A combined control scheme consisting of a feedforward torque and a PID feedback controller is adopted to track the joint trajectories. Based on the principle of virtual work, a new and simple method is proposed to evaluate the feedforward torque. To improve computational efficiency, an OpenMP based parallel computational strategy is used to solve the large scale equations of motion. Three examples are given to verify the effectiveness of the proposed formulations and demonstrate the complex dynamics of rigid-flexible multibody systems with multiple cylindrical clearance joints.
How Multibody Dynamics Simulation Technology is Used
RecurDyn has the capability of simulating the multibody dynamics of rigid and flexible bodies using the FFlex module. In this paper, RecurDyn is used to analyze a rigid-multibody system with multiple cylindrical clearance joints. RecurDyn simulations agree well with a simplified model proposed by the author and provide validity to both methods used to analyze cylindrical clearance joints.
