The main objective of this paper is to propose a new friction compensation mechanism applied to robotic actuators, and to confirm it through experimental results. Friction is a phenomenon that changes with time and with actuator’s operational conditions. To deal with these parameters variations, it is proposed a neuro-fuzzy algorithm for friction identification and compensation. A Neural Networ...

A discrete-time sliding mode control design for a ball-screw driven positioning table is presented. The basic feature of this design is that high speed and high positioning accuracy can be met despite of the fact that the controlled process suffers from friction and mechanical flexibility. Disturbance rejection, in the form of friction compensation and vibration suppression, is the main focus o...

A study of di erent classes of controllers for mechanisms under the in uence of low velocity friction is conducted. Many methods are proposed in the literature for friction compensation, but there has been no signi cant analysis of these methods with respect to each other. Also lacking in the literature is some form of categorization, under which it is possible to describe and study their perfo...

Friction appears in all mechanical systems and has a significant impact on control. This paper presents simple but effective nonlinear friction compensation method for a drillstring system, by considering the stickslip motion of the bit on the bottom hole assembly (BHA) in oil wells. Due to nonlinear problem at nearzero velocity where the torque exerted on bit is a function of the bit speed, th...

A study of diierent classes of controllers for mechanisms under the innuence of low velocity friction is conducted. Many methods are proposed in the literature for friction compensation, but there has been no signiicant analysis of these methods with respect to each other. Also lacking in the literature is some form of categorization, under which it is possible to describe and study their perfo...

This paper aims at presenting a model based compensation command law developed in order to enhance the transparency of haptic interfaces for low mass objects manipulations in virtual environments. After presenting the context and related work of the study, the model based compensation command law is developed and implemented on a 6-dofs haptic interface. Uncertainties of the model (friction coe...

The paper presents experimental results of friction parameter identification for two different systems: rotational arms of a direct-drive spherical manipulator and linear slide tables. Parameters of the static part of the LuGre friction model are estimated. Several experiments are reported in which selected friction compensation methods are employed for tracking at low velocities. Two compensat...

In this paper we present two controllers for robots that combine terms for the compensation of gravity forces, and the forces of friction of motors and gearboxes. The Low-Friction Zero-Gravity controller allows a guidance of the robot without effort, allowing small friction forces to reduce the free robot motion. It can serve to aid users providing kinesthetic demonstrations while programming b...

In the general framework of tracking control of hydraulic servo systems, this paper presents a comparison between two main possibilities to include friction information in the picture: experimental identification and estimation. Experiments were first conducted in order to find a suitable representation for friction in the system. We then looked at two observers reported in the literature (know...