Publications / 2006 Proceedings of the 23rd ISARC, Tokyo, Japan

An Open-Loop vs. Closed-Loop Backhoe Excavator Control System

Eugeniusz Budny, Miroslaw Chlosta
Pages 560-564 (2006 Proceedings of the 23rd ISARC, Tokyo, Japan, ISBN 9784990271718, ISSN 2413-5844)
Abstract:

The excavation process has got two main features. The first one is the soil digging. It can be regarded as a quasi-static process in fact, in which the acceleration could be neglected. The second one is the soil transportation and bucket discharging. It can be considered as a dynamic process. Some parts of these features would be automated. There are two main control systems, open and closed-loop control. The main aim of the paper is to present the application of these two systems and compare them. The control systems were tested during the digging process. It begins with the bucket on the primary digging position and ends when it is filled. The paper starts with description of the excavator control systems components. They have got hierarchical structure. The first is the hardware level: sensors, actuators, valves. The PLC executes a direct control on this level. The links between objects would be realized via CAN network. The excavator’s control system realizes a simple excavator’s bucket motion along prescribed trajectory algorithm. The software level assures calculation of the trajectory parameters, i.e. coordination of the milestones. The bucket velocity was the input quantity. It means that the valve’s spool displacements are calculated for each actuator separately. Machine counterbalance and actuators parameters would be the limits of the process. The results of the two systems testing procedure would be presented and compared.

Keywords: excavator, control system, open closed loop