Powerline robotics is slowly becoming key tools for electric utilities. Contrary to drones that are usually limited to inspection tasks, wheeled robots like LineRanger can perform a broader range of applications. In this paper, a suite of mechanical devices is featured, as several new asset management tasks were recently added to LineRanger’s capabilities. While previous applications focused on non-contact inspection (visual, electro-magnetic, etc.), the new tasks at hand involved reaching adjacent conductors to probe line components with micro-Ohmmeter, installing and retrieving custom build sensors for multi-day line monitoring, and assessing aging conductors surface properties, to refine their thermal model and optimize the line capacity during heat waves. All three applications were recently field validated onto LineRanger, and mechanical design insights shall be presented for each module.

Even if UAVs undoubtedly had a profound effect on the visual inspection capabilities of transmission lines, rolling robots, especially for bundled configurations, will still play an extensive role in the maintenance of these strategic assets. As such, LineRanger is among the most efficient and capable wheeled platform, that can travel at an average speed of 8 km/h. In this paper, LineRanger mechanical design insights are shared, unfolding how strictly mechanical solutions deals with ease of obstacle crossing, ease of installation procedure without requiring any linemen to access the high voltage environment area, and ease of deployment of dedicated, custom-made sensors onto the line component of interest. This novel robotic platform is now being deployed onto Hydro-Quebec power grid network, performing high value applications.

In this paper, a slip-limiting controller for redundant line-suspended robots is presented. This kind of robot is usually equipped with v-shaped wheels, which brings uncertainty about the effective wheel radius, particularly when crossing obstacles. The proposed algorithm is able to estimate and limit wheel slippage in the presence of such uncertainty, relying only on wheel angular velocity measurements. Slip limitation occurs in the control allocation algorithm and hence is decoupled from the high-level velocity controller, allowing a broad applicability in centralized control approaches. Experimental results on Line Ranger show that it effectively reduces wheel slippage compared to traditional centralized control while being more energy efficient than traditional decentralized control approaches.

Robotic platforms dedicated to powerline inspection are often complex to operate, take several minutes to cross any obstacle, and must be operated by highly trained specialists. To further its goal of massive inspection of its power grid, Hydro-Québec developed an innovative robot that is simple to operate and can be used directly by line maintenance technicians. LineRanger was developed following the field deployment of LineROVer and LineScout but aims at surpassing them in terms of inspection efficiency. With an ingenious and passive obstacle-crossing system, this new robot allows large-scale inspection of bundled-type powerlines, since the obstacle crossing time is considerably reduced. In this paper, details on the robot's key features are presented along with its mathematical analysis, which guarantees its stability on flexible bundles and directly influenced the design. Finally, the LineRanger prototype is presented, with insights about its first field deployments.

This paper presents the design of a multirotor unmanned aerial vehicle (UAV) capable of landing semiautomatically on a power line while carrying a payload. The vehicle then rolls along the line to perform an inspection. Special attention is given to the vehicle's onboard vision system, which consists of a monocular camera and LiDAR used together to compute the pose of the vehicle relative to the power line. Landing assistance is provided to the pilot by a position-based visual controller that aligns and keeps the vehicle centered along the power line. The pilot remains in control of vertical and longitudinal movement during descent. The proposed approach was tested on a full-scale test line and shows promise for future applications of high value to the electric industry such as non-destructive testing of power transmission lines.

This paper presents a new 6-DOF serial manipulator with five revolute joints and one prismatic joint, designed to operate equipment inside Hydro-Que¿bec underground distribution vaults. The manipulator is an upgraded model developed after field testing a 6-DOF wrist-partitioned serial manipulator prototype. The new manipulator architecture is intended to solve space constraint problems in some vaults. This paper covers the geometrical model of the new manipulator, an analytical solution for the inverse kinematic equations, the dynamic model used to compute torques/forces at the actuators, and simulations performed with MATLAB and CATIA. The manipulator is the only robot application in the world designed to operate equipment on underground distribution power lines.

This video summarizes the R&D phases of the first robot prototype designed to operate and maintain equipment in vaults for Hydro-Québec's underground distribution lines, carried out between 2003 and 2009. Detailed segments discuss project's context, proof of concept, simulations, description and design of robotic platform subsystems, prototype testing at IREQ in the lab and in an outdoor vault, field testing in Montreal on a Joslyn switch in a de-energized vault, and the future of the project.