A portable, multiprocess, track‐based robot for in situ work on hydropower equipment

Abstract

In the hydropower industry, in situ maintenance work of turbine runners to address issues such as cavitation damage and cracking is mainly performed manually. Alternatively, the entire turbine requires disassembly and is repaired off site at greater cost. This paper presents the development and fundamentals of robotic technology designed to perform work in situ on hydroelectric equipment. A second paper surveys field implementations carried out with the technology over the past 15 years. A new portable manipulator was designed with unique track-based kinematics well suited to accessing turbine blades in a confined space. The robot is driven by position-controlled stepper motors but relies on a hybrid force/position controller to perform processes in contact with the work piece, such as grinding. A major obstacle for robotic repair is excessive programming time. As most work is done on curved surfaces, the robot relies on a model of curvilinear space for trajectory generation. The robot is coupled to an accurate measurement system to scan surface topography in three dimensions. It has been equipped to perform several processes, such as welding and grinding, to facilitate the manufacture and maintenance of hydropower equipment. Despite the robot's inaccuracy and flexibility, surface profiles may be reconstructed with great accuracy through the use of a controlled metal removal rate strategy that relies on an innovative dynamic model of the grinding process. C

Hydro-Québec's Power Line Robotics Program: 15 years of development, implementation and partnerships

“…The Robotics Group, part of IREQ's Robotics and Civil Engineering department, has been active for more than 20 years and it played a crucial role in developing and implementing several innovative technologies into the core activities of various business units: power generation, transmission, and distribution. SCOMPI (Figure 1), a portable multi-process robot for in situ work on hydropower equipment [7], has been deployed over 40 times on Hydro-Québec infrastructures and on the equipment of several major industry players around the world. The robot's unique design enables it to perform several refurbishment processes, such as welding, grinding, gouging, hammer peening and more recently, in situ heat treatment.…”

Field repair and construction of large hydropower equipment with a portable robot

“…Two plumb lines facing the tracks were monitored by two laser micrometers to create a reference plane while six eddy current range sensors measured the distance between the surface and the measurement system as shown in Figure 27. The method is described in Hazel et al (2012a). Precision typically obtained on carbon steel varies between 18 and 22 μm.…”

“…Designed for quick and simple installation, the robot can deposit weld metal on complex shapes or reconstruct profiles through grinding. For more information on the robot, its theory of operation, and background on what justified its development, the reader is referred to Hazel, Côté, Laroche, and Mongenot (2012b). Figure 1 shows SCOMPI on a curved track with a grinding tool mounted on its quick connect.…”

Study and validation testing of the dynamics of a robotic system with flexible links and joints

“…In order to automate and optimize repairs to hydropower equipment such as turbines, Hydro-Québec designed a compact, lightweight robot with six degrees of freedom [1,2]. The robot, called "SCOMPI", is used for repair jobs involving material removal through grinding (see Fig.…”