Identification of Contact Dynamics Parameters for Stiff Robotic Payloads

Abstract

This paper investigates and demonstrates the feasibility of identifying contact dynamics parameters for stiff robotic payloads using a robotic system. The contact dynamics model for stiff payloads is motivated, and theoretical parameter values and bounds are provided. Then, the effect of nonidealities such as surface roughness and plastic deformation on the theoretical values is demonstrated. A row-wise-scaled total least-squares parameter estimation algorithm is proposed and applied to experimental data measured using the Special Purpose Dexterous Manipulator Task Verification Facility manipulator at the Canadian Space Agency. The experimental results are compared to a separate set of experiments with a material testing machine as well as finite-element modeling results. Finally, the experimental findings are generalized by providing guidelines for the maximum identifiable payload stiffness as a function of the position resolution, the maximum exertable force, and the structural stiffness of the robotic system.

On-line estimation of variable stiffness in flexible robot joints

“…While many papers have dealt with stiffness estimation in contact situations between the end-effector of a rigid robot and the environment or a human (Diolaiti et al, 2005;Verscheure et al, 2009;Ludvig and Kearney, 2009;Coutinho and Cortesao, 2010), less work has been devoted in the past to the estimation of variable, nonlinear stiffness of flexible joints.…”

System identification for helicopter yaw dynamic modelling

“…However, the parameters of most helicopters' dynamic model distribute in a fairly wide range [8], [22]. GA is tends to be trapped into local extremums if identification is performed directly [11].…”

“…General approaches for helicopter dynamic modeling are first principle analysis [1][2], and system identification. As modeling from real-flight tests, system identification methods are deemed as an accurate approach to model helicopter dynamics [3], especially frequency-domain identification methods [4][5][6][7][8].…”

Comparison of position and force-based techniques for environment stiffness estimation in robotic tasks

“…This is problematic for tasks with low contact forces, making it difficult to assess free-space/contact transitions. Additionally, the resolution of joint encoders may be insufficient to compute the end-effector position to properly account for minimal displacements that occur in contacts with highly stiff surfaces [16], [1]. For example, a contact force can change a few Newton without detecting positional changes [5].…”