Safety Wheel Drive: disruptive electric wheel drive technology for integration with autonomous mobile robots

In logistics and other collaborative spaces (where humans and industrial robots work together), the adoption of autonomous mobile robots (AMRs) and automatic guided vehicles (AGVs) continues to increase.

The safety requirements for AMRs and AGVs are comprehensive – they need to be, to reduce the risk of collisions, other accidents, and injuries.

Under the ISO 3691-4 international safety standard, driverless industrial vehicles and their systems must have the following safety functions:

• Speed control

• Speed detection and limitation

• Human presence detection

• Braking system

• Emergency stop function

AGV/AMR designers must keep up with both the current safety requirements for mobile robots and the rapid evolution of industrial automation technologies.

Here’s a video of a mobile robot in action at one of our production facilities:

There are a lot of yellow crates in that video, but did you spot the bright yellow wheel? That’s our Safety Wheel Drive electric wheel.

The Safety Wheel Drive (SWD) system is an all-in-one solution for safe operation and controls, combining the following parts in a compact build:

• Wheel

• Gearbox

• Motor

• Safety encoder

• Safe motion control

There’s no longer a need to source these different components from several manufacturers, or to spend extra time verifying their functionality and compatibility.

In this way, SWD streamlines the AGV/AMR design process – reducing the number of build components needed by up to 50%.

The ‘plug and play’ architecture is reassuringly simple, unique and innovative enough to lead the way in the evolution of mobile robot design. At the time of writing, no other equivalent self-contained solution is available in the US.

The SWD’s built-in safety features include:

• Safe Torque Off (STO) – motor disconnection when a stop is requested

• Safely Limited Speed (SLS, SLSa) – to prevent hazardous situations

• Safe Maximum Speed (SMS) – to secure operating range

• Safe Brake Control (SBC) – to ensure a standstill

• Safe Direction Control (SDI) – in case of collision risk

Together, they cover the safety requirements needed for compliance with several international safety standards:

With these integrated technologies, the certification process for an AGV/AMR built with SWD is quicker and kept under control. Safety is assured, so designers can concentrate on optimizing the HMI and control elements of each mobile robot.

Using other IDEC safety products in combination with Safety Wheel Drive further simplifies compliance with ISO 3691-4.

• SE2L Advanced safety laser scanner: the obstacle detection function can engage speed control and limitation. The SWD’s many safe motion monitoring functions can be spread out across scanner detection zones.

• XA/XW emergency stop switches: emergency stop function. Short body and 16mm diameter options fit easily onto smaller AGVs/AMRs.

• HK2H/HK2L safety edge switches: detection of human/obstacle presence in the mobile robot’s path. The HK series’ R80 (80mm) bend radius makes installation on AGVs/AMRs simpler, and takes up less space.

SWD’s versatility and the variety of combinations offer suitability for numerous industrial applications. As AGVs and AMRs become a more common site on factory floors, at logistics facilities and on production lines, more custom solutions will be needed to build mobile robots for specific purposes and situations.