Optimal movement of the suspended payload

U radu je prikazan jedan od mogućih načina optimizacije kretanja visećeg tereta. Razvijena procedura optimizacije je primenjena na dizalične uređaje sa grabilicom, kao što su pretovarni most i lučka dizalica. Procedura optimizacije je podeljena u dve faze. Prva faza predstavlja optimizaciju kretanja grabilice i tereta tj. visećeg tereta. Druga faza optimizacije sastoji se iz određivanja kretanja mehanizama dizaličnih uređaja, na osnovu dobijenih optimalnih putanja i parametara kretanja grabilice i tereta. Oblik prikazanog matematičkog modela omogućuje direktnu primenu modela teorije optimalnog upravljanja tj. optimizacija kretanja visećeg tereta je izvedena primenom Pontrjaginovog principa maksimuma. Osnovni cilj optimizacije je postizanje minimalnog radnog (istovarnog) ciklusa, smanjenje potrošnje energije kao i rasipanja materijala tokom pražnjenja grabilice. Svi relevantni izrazi su izvedeni u analitičkom obliku.This paper presents one of the possible ways to optimize the movement of the suspended payload. Application of presented optimization procedure is shown on grab crane devices such as unloading bridge and harbour crane. The optimization procedure is divided into two phases. The first phase is optimization of the cargo and grab (suspended payload) movement. The second phase is determination of movement, of the grab crane device mechanisms, upon obtained optimal path and parameters of cargo and grab (payload) movement. Shape of presented mathematical model makes possible direct application of optimal control theory methods i.e. optimization of the payload movement is determined using Pontryagin’s maximum principle. The basic aim of optimization is to attain the minimal working (unloading) cycle, spending of energy and material dissipation during the grab discharging. All relevant expressions are derived analytically.

Anti-swing control of overhead cranes

Overhead cranes are widely used for transporting large and heavy suspended objects such as shipping containers. Acceleration and deceleration of the crane generally induce swinging motion in the suspended payload. A method is presented to find the trajectory for an overhead crane that will ensure the transfer of the payload in the shortest time and with minimum swinging along a specified path. The overhead crane and the suspended payload are modeled as a double pendulum with motion in three dimensional space. The equations of motion of the overhead crane and the payload are transformed in terms of a single path parameter which represents single degree of motion along the path. The resulting set of equations defines the phase space of admissible motion constrained by the path geometry and the forces exerted by the crane. By applying dynamic programming principles to the transformed set of equations of motion, the trajectory with the shortest time and with minimum swinging is determined

Magnetic suspension systems for space applications

An overview of techniques is presented used in the described magnetic suspension systems. Also a review is presented of the systems already developed, which demonstrate the usefulness, applicability, and flight readiness of magnetic suspension to a broad range of payloads and environments. The following subject areas are covered: programs overview; key concepts; magnetic suspension as an isolator and as a pointer; pointing and isolation systems; magnetic actuator control techniques; and test data

Mixed H₂/H∞ Tracking Control with Constraints for Single Quadcopter Carrying a Cable-suspended Payload

In order to control a single quadcopter with a cable-suspended payload to follow the desired trajectory, a mixed H₂/H∞ controller with constraints is developed. Firstly, the Euler-Lagrange dynamic model is built and linearized. Then the extended model for path tracking problem is designed. Based on linear matrix inequality (LMI), state feedback controller H₂ and H∞ with constraints is illustrated. Aiming to maintain a good balance in transient behaviors and frequency-domain performance, the mixed controller is presented. Finally, the control strategies are utilized in a simulation test and the result validates the proposed method