Authors: Hassan Shibly; Nidal Al-Masoud
Addresses: Robotics and Mechatronics, School of Engineering, Science, and Technology, Central Connecticut State University, 1615 Stanley Street, New-Britain, CT 06050, USA ' Mechanical Engineering, School of Engineering, Science, and Technology, Central Connecticut State University, 1615 Stanley Street, New-Britain, CT 06050, USA
Abstract: This paper examines expanding the range of manoeuvrability, ease of motion and improving the mobility system of Mars rovers. The focus of the research is on the enhancement of rover's speed and mobility under numerous constraints imposed by rugged and difficult-to-navigate terrains that include abrupt change of ground level, soft soil, obstacles and rocks. The article presents a study and simulation of the dynamic response of a free fall of a quarter vehicle model with rigid wheel on a soft soil. A simplified form of Bekker's equation is incorporated in the numerical solution of the governing equations of motion. The response of the dynamic interaction of rigid wheel and soft soil has three stages: sinkage stage, equilibrium stage and pullout from soil stage. The rigid body mode of the dynamic response is required to let the sprung mass pullout the rigid wheel from soft soil. The simulation results demonstrate that the first three stages of the first fall are the most significant. They have larger sinkage, larger resistance force and larger amplitude of dynamic response. The existence of damping reduces the magnitudes and prevents the unsprung mass from pulling out the wheel from the soil. The normal force on the rigid wheel for this case can be approximated and replaced by a triangle-shaped distribution. The simulations results conform to the theoretical counterparts.
Keywords: dynamic modelling; dynamic response; equivalent sinkage resistance; interaction with soft soil; nonlinear soil resistance; rigid wheel-soil sinkage; sinkage by free fall; soft soil resistance; stages of rigid wheel soil interaction.
International Journal of Mechanisms and Robotic Systems, 2017 Vol.4 No.1, pp.61 - 79
Received: 17 Nov 2016
Accepted: 22 Jul 2017
Published online: 13 Oct 2017 *