Drives & Controls Magazine September 2023

n TECHNOLOGY September 2023 16 SCHNEIDER ELECTRIC HAS LAUNCHED a family of collaborative robots (cobots) in five sizes, with payloads from 3–18kg, working radii from 626–1,327mm, operating speeds from 1.5–3.5m/s, and positioning repeatabilities from ±0.02mm to ±0.03mm. The Lexium cobots are claimed to have some of the smallest footprints in the industry, requiring 30-40% less space than traditional robots. The six-axis cobots, which have already been demonstrated at various trade exhibitions including the PPMA Show in 2022, are designed to work alongside humans. They take safety into account with built-in collision detection, rounded edges and low weights, reducing the risk of injury. Simple programming, quick set-ups, and ease of use and training are said to help recover investment costs quickly. Installing the IP54-protected cobots requires minimal changes to existing layouts. They can be mounted on floors, walls or ceilings. The cobots can be taught motion profiles by guiding the arm manually. This handguided teaching simplifies programming and eliminates the need for detailed parameterisation of motion settings. The cobots are ready to use quickly and can be adjusted to new conditions at short notice. Specialised knowledge of programming or commissioning is not needed. Graphic programming can also be used to change applications and to adapt to production changes. The cobots integrate with Schneider’s open EcoStruxure plug-and-play platform, cutting design, development and commissioning times, and making delivery and start-up quick and easy. They can link with the EcoStruxure Machine Expert Twin tool which provides simulation and digital twin functions. “The release of the Lexium cobot marks a crucial step in next-generation robotic systems,” says Mike Teller, Schneider Electric’s global OEM strategy and sustainability leader. “Traditional industrial robotic systems must be designed into processes from day one. Although they can be very effective at accurately and consistently performing operations which are repetitive and arduous for workers, their speed and power make them unsuitable to work alongside people. “The Lexium cobot, on the other hand, is intentionally designed to work with people, and offers a fast return on investment, easy integration without the capital costs of major process rework, and helps make plant more agile, productive, and safe environments.” A BRITISH DRIVE DEVELOPER – MiltonKeynes-based Helix – has produced an electric motor that weighs only 28kg, yet is capable of delivering 650kW of continuous power and 398Nm of continuous torque. The 261mm-long and 206mm-diameter motor has a maximum speed of 25,000 rpm. Helix developed the SPX177 motor for a hypercar manufacturer which wanted to power a vehicle with a single 650kW motor. The motor weighs less than 1/7th as much as the latest, boosted internal combustion engines, producing an equivalent continuous output. Helix’s X-Division engineered the motor to minimise losses and heat generation, especially at high speeds. They wound the motor to reduce losses through resistance, creating a low-inductance machine. “It’s small and weighs just 41kg, including the 13kg inverter,”says Helix’s chief engineer, Derek Jordanou-Bailey. “It is a 2 x 3-phase motor, so its current is shared across two inverters – a necessary approach to meet the phase current demands at‘normal’DC voltages at this extremely high power level. Both the motor and inverter have extremely high power densities. Six high-voltage cables connect the inverter to the motor, while an LV connector carries the various control signals. “The customer told us what peak power they wanted and demanded a very high steady-state output,” Jordanou-Bailey recalls. “Right now, it is tricky to deliver sufficient energy to maintain that level of output, but in time it is likely to be possible and the customer wanted to ensure their flagship model was ready for that. “We needed an architecture that minimises losses and the heat generated, especially at high speed, and that meant quite a change in the way the motor was wound, since minimising resistance losses results in a very low-inductance machine,” he adds. “The switching in the inverter can generate lots of noise and harmonics and this is more challenging with a lowinductance motor. The software team did a great job developing a new way of controlling the phase currents.” On a test stand, the motor has delivered a peak of more than 700kW. “It could potentially deliver more, we didn’t push it,” says Jordanou-Bailey. He concedes that the vehicle’s battery will weigh much more than an engine’s fuel store, but argues that the motor’s low mass allows flexibility in terms of where it is installed, helping to optimise the car’s architecture for a low centre of gravity and cleaner aerodynamics, for example. There is a proposal to build a small initial batch of the motors. UK-developed 28kg motor delivers 650kW and 398Nm Six-axis cobots can handle payloads of up to 18kg Schneider’s Lexium cobots are designed to work safely alongside humans Helix’s low-inductance motor (seen here with its twin inverter) produces a 650kW output