Increasing the Automation Level of Hydraulic Secondary Breaker Systems : An End-to-End Concept

Abstract

Crushing blasted ore is an essential phase in the extraction of valuable minerals in the mining industry. The first stage in crushing is to process the raw blasted material, which typically contains a broad size distribution. To prevent oversized material from entering into the primary crusher, a metal grate is often used to separate large fragments. A secondary breaker, that is, a hydraulic manipulator with an impact-hammer, is then used for controlled size reduction of the oversized boulders. This is an essential task for ensuring continuous material flow and preventing blockages.

The mining industry, as many other industries, is currently expanding, moving toward increased automation with huge investments being made in research and development. Driven by safety and economic incentives, the demand for autonomous secondary breaking—which is almost exclusively performed manually with line-of-sight teleoperation—is expected to significantly increase in the near future.

This thesis aims to develop an end-to-end concept for an autonomous secondary breaker system. To accomplish this task, this thesis addresses three research problems (RPs) directly related to the automation of the secondary breaking task, that is, manipulator control, machine vision, and high-level autonomous operation coordination, along with one RP related to the force-reflective teleoperation of hydraulic manipulators. The latter was considered for a backup control method of the secondary breaker boom.

Six publications have been generated, addressing the RPs. The work culminates in the concept autonomous breaker system realized on top of a commercial breaker boom. The focus in development of the autonomous concept was to maintain the original functionality of the breaker boom system. In terms of the last RP concerning teleoperation, the work has resulted in significant advances toward effective teleoperation control of dissimilar leader–follower systems. The experimentally verified control theory foundation can be used as a basis for the teleoperation of a wide class of manipulators.