Design and Implementation of Model-Predictive Control With Friction Compensation on an Omnidirectional Mobile Robot

Abstract

This paper presents and discusses the implementation results of a model-predictive control (MPC) scheme with friction compensation applied to trajectory following of an omnidirectional three-wheeled robot. A cascade structure is used with an inverse kinematics block to generate the velocity references given to the predictive controller. Part of the control effort is used to compensate for the effects of static friction, allowing the use of efficient algorithms for linear MPC with constraints. Experimental results show that the proposed strategy is efficient in compensating for frictional effects as well as for tracking predefined trajectories.

Full-body collision detection and reaction with omnidirectional mobile platforms: a step towards safe human–robot interaction

“…[3] derives the dynamic equation including the rolling kinematic constraint for a mobile platform similar to ours, but uses an oversimplified dynamic friction model with respect to the effects of roller friction. Studies that incorporate static friction models include [26,1], but again these use oversimplified models that ignore omniwheel and roller dynamics. The studies above are mostly theoretical, with few experimental results.…”

“…To provide these capabilities, we take the following steps: (1) we develop a floating base model with contact and rolling constraints for an omnidirectional mobile base; (2) we process torque sensor signals using those models and statistical techniques; (3) we estimate roller friction and incorporate it into the constrained dynamics; (4) we implement a controller to quickly escape from the collisions; (5) we present an experimental testbed; and (6) we perform experiments including several calibrated collisions with the testing apparatus, and a proof of concept experiment in which the robot moves through a cluttered environment containing people against whom it must safely collide.…”

Active omni wheel capable of active motion in arbitrary direction and omnidirectional vehicle

“…Figure 1 shows an example of an omnidirectional wheel called the omni wheel. The omni wheel has a disk shape like a conventional wheel and can move in any direction (Asama et al, 1995;Barreto S. et al, 2014;Conceição et al, 2009;Fisette et al, 2000;Huang, 2013;Huang and Tsai, 2009;Iida et al, 2008;Kalmár-Nagy et al, 2004;Kim and Kim, 2014;Leow et al, 2002;Liua et al, 2008;Loh et al, 2003;Sharbafi et al, 2010;Tsai et al, 2011;Ushimi et al, 2003;Williams II et al, 2002). The omni wheel has free rollers around its outer circumference that can rotate passively.…”

“…Various reports concerning omni wheels have been published, such as reports on motion analysis and modeling of these wheels (Barreto S. et al, 2014;Conceição et al, 2009;Fisette et al, 2000;Huang, 2013;Leow et al, 2002;Loh et al, 2003;Williams II et al, 2002), their control (Kalmár-Nagy et al, 2004;Kim and Kim, 2014;Liua et al, 2008;Sharbafi et al, 2010), and the development of mobile robots or mobile devices using the wheels (Asama et al, 1995;Huang and Tsai, 2009;Iida et al, 2008;Sharbafi et al, 2010;Tsai et al, 2011;Ushimi et al, 2003). Another example of an omnidirectional mechanism is the Mecanum wheel (Dickerson and Lapin, 1991;Diegel et al, 2002;Harris, 2002;Indiveri, 2009;Saha et al, 1995;Salih et al, 2006;Viboonchaicheep et al, 2003).…”

Low level control of an omnidirectional mobile robot

“…The nonlinearities in the mobile robots are mainly due to the friction. Many authors have addressed the problem of friction compensation, using model based and model free-based techniques [2]. The friction model-based approach consists of feedforward and feedback control that introduced the friction model into the system to cancel out the nonlinear effect.…”