Dynamic Simulation of a Mobile Manipulator with Joint Friction

A Novel Explicit Canonical Dynamic Modeling Method for Multi-Rigid-Body Mechanisms Considering Joint Friction

“…The geometric model of the revolute joint and the prismatic joint is shown in Figure 8, where R n is the friction arm, R p is the pin radius, R b is the bending reaction arm, τ r u is the magnitude of the constraint torque of the constraint axis of the revolute joint, f r u is the magnitude of the constraint force of the constraint axis of the revolute joint, f m u is the magnitude of the constraint force of the motion axis of the revolute joint, f p u is the magnitude of the constraint force of the constraint axis of the prismatic joint, τ p u is the magnitude of the constraint torque of the constraint axis of the prismatic joint, and τ m u is the magnitude of the constraint torque of the motion axis of the prismatic joint. According to Equation (39), the analysis of τ r u of the revolute joint and f p u of the prismatic joint has been completed. Next, f r u and f m u of the revolute joint and τ p u and τ m u of the prismatic joint will be analyzed.…”

“…According to whether the kinematic chains of multi-rigid-body mechanisms are closed, multi-rigid-body mechanisms can be divided into open-chain mechanisms (including single-chain mechanisms and tree-chain mechanisms) and closed-chain mechanisms (also called parallel mechanisms) [39]. The inherent motion constraints of the closed chain complicate dynamics research [40,41], considering that joint friction strengthens the coupling degree of the closed-chain dynamic model and increases the difficulty of such research [42].…”

Optimization of Manipulator Drive Mechanisms in Hydraulic Excavators on the Basis of the Tribological Criterion

“…Vector r ti of the center of the kinematic chain link L i mass in the absolute coordinate system is determined through the following equation: r ti = r i + A io _ t i ; (8) where A io is the homogeneous transformation matrix used to transfer the vector quantities from the local coordinate system O i x i y i z i of link L i to the absolute coordinate system OXY Z.…”

“…During the manipulation task of hydraulic excavators, the elements of manipulator kinematic pairs experience a pronounced relative movement under the loading accompanied by tribological phenomena, i.e., friction and wear, between the elements of the machine's kinematic chain joints. The consequences of tribological phenomena are loss of energy of drive mechanisms and the reduction of the lifecycle of joint elements [8,9]. This paper rst analyzes the functional, structural, and tribological parameters of kinematic chain joints in the excavating manipulator of a hydraulic excavator and, then, de nes the tribological criterion for the optimal determination of parameters of manipulator drive mechanisms on the basis of the loss of energy due to friction in mechanism joints.…”