Estimation of Leg Stiffness Parameters of a 6DOF Parallel Mechanism
The paper describes a novel algorithm for estimation of the stiffness parameters of a 6DOF parallel mechanism with a known topology and geometry. The mechanism is composed of a platform guided by six or more legs with Spherical-Prismatic-Universal joints. A substitute compliance of each leg is modelled by linear springs in the P-joints. Such structure has a broad application in robotics, machining tools, and car suspension systems. The stiffness parameters of the legs are considered as unknown or hard to measure directly. These parameters are estimated using as an input data the spatial displacements of the platform from an initial pose, measured under specified quasi-static loads. The presented method is exemplified on a five-rod wheel guiding mechanism of an actual passenger car. Results of the mechanism measurements carried out on a test stand are used. Five static rates of elastomeric bushings installed in the mechanism rods are determined taking into account the influence of the measurement noise.
KeywordsMachine Tool Stiffness Parameter Spatial Displacement Dimensional Synthesis Spring Rate
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