Computer Controlled Systems: Theory and Design

This note presents a modification of the integrated friction model structure proposed by Swevers et al. (2000), called the Leuven model. The Leuven model structure allows accurate modeling both in the presliding and the sliding regimes without the use of a switching function. The model incorporates a hysteresis function with nonlocal memory and arbitrary transition curves. This note presents two modifications of the Leuven model. A first modification overcomes a recently detected shortcoming of the original Leuven model: a discontinuity in the friction force which occurs during certain transitions in presliding. A second modification, using the general Maxwell slip model to implement the hysteresis force, eliminates the problem of stack overflow, which can occur with the implementation of the hysteresis force.

Technical Note: modification of the Leuven integrated friction model structure

Virtual and remote labs in control education: A survey

A general controller evaluation method based on three performance and robustness criteria is presented. It can be used to compare controllers of different structures, but also as a design method to find the optimal parameter setting for a controller of given structure. In this way optimal PI and PID controllers have been designed for a set of different plants. Clear regularities have then been noticed and utilised to formulate sets of tuning rules for non-oscillating stable plants and for plants with integral action. The rules demand very little plant knowledge but the resulting controllers are close to optimum. Furthermore, the user may adjust one or two of the tuning parameters and still get very good results. This means that the user has some freedom to manage the important trade-off between performance, robustness and control activity.

Robust and optimal tuning of PI and PID Controllers

This paper presents an open course in the University Network of Interactive Laboratories, which offers several virtual and remote laboratories on automatic control, accessible to anyone. All the details on one of these labs (a two electric coupled drives system that allows performing control practices in a 2 $\times $ 2 MIMO system with industrial applications) and the activities that can be performed with it are given. We use a low-cost solution for developing the virtual and remote labs shared in this open course, based on the use of a free authoring tool Easy Java/Javascript Simulations (EJsS) for building the laboratories’ user interfaces and a cheap development platform board (BeagleBone Black). The virtual and remote labs are deployed into a free Learning Management System (Moodle) Web environment that facilitates their management and maintenance.

Open and Low-Cost Virtual and Remote Labs on Control Engineering

Characterization of symmetric send-on-delta PI controllers

In this paper we present a new friction model for industrial robot manipulators that takes into account temperature effects. In particular, after having shown that friction might change very significantly during robot operations, two solutions based on a polynomial description of the joint friction are proposed and compared. In both cases the models proposed do not need a measurement of the joint temperature, but just of the environmental temperature, so as to be easily applied in industry. Experimental results demonstrate the effectiveness of the applied methodology.

Friction modeling with temperature effects for industrial robot manipulators

The paper presents a fast online predictive method to solve the task-priority differential inverse kinematics of redundant manipulators under kinematic constraints. It implements a task-scaling technique to preserve the desired geometrical task, when the trajectory is infeasible for the robot capabilities. Simulation results demonstrate the effectiveness of the methodology.

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Predictive Inverse Kinematics for Redundant Manipulators With Task Scaling and Kinematic Constraints

Fractional robust PID control of a solar furnace

In this paper, we present a novel methodology to design fractional-order proportional-integral-derivative controllers. Based on the description of the controlled system by means of a family of linear models parameterised with respect to a free variable that describes the real process operating point, we design the controller by solving a constrained min–max optimisation problem where the maximum sensitivity has to be minimised. Among the imposed constraints, the most important one is the new generalised isodamping condition, that defines the invariancy of the phase margin with respect to the free parameter variations. It is also shown that the well-known classical isodamping condition is a special case of the new technique proposed in this paper. Simulation results show the effectiveness of the proposed technique and the superiority of the fractional-order controller compared to its integer counterpart.

Manuel Beschi

Papers

Characterization of symmetric send-on-delta PI controllers

Friction modeling with temperature effects for industrial robot manipulators

Predictive Inverse Kinematics for Redundant Manipulators With Task Scaling and Kinematic Constraints

Fractional robust PID control of a solar furnace

The generalised isodamping approach for robust fractional PID controllers design