Functional Safety of the Hydraulic Drive Control System of a Tracked Undercarriage.

In the study, the functional safety of the hydraulic drive control system of a tracked undercarriage used as a mobile platform for a robotic bricklaying system (RBS) was evaluated. Hazards and risks caused by the hydraulic drive control system of the rubber track undercarriage were identified. The schematic diagram and main components of the conventional hydraulic drive control system of a tracked undercarriage are presented. The functions and parameters of the components of the hydraulic power and control system are discussed. In a conventional hydraulic drive, the safety function is fulfilled by failsafe brakes built into the hydraulic motors. In order for RBS to work safely on the construction site, it was necessary to introduce an advanced safe control system for the hydraulic drive of the tracked undercarriage. An advanced safe control system for the hydraulic drive of the tracked undercarriage includes hydraulic control valves with safety functions, a two-channel category 3 safe control architecture, and a safety microcontroller. SISTEMA software tools were utilized to determine safety functions and calculate their specifications. Based on the specifications of the safety function associated with the category of the safety control architecture, the achievable performance level of the hydraulic drive control system for the tracked chassis was determined.