Abstract: This application describes independent safety systems for robotic systems using a safety rated PLC. For example, a robotic safety system can include a first sensor that is operatively coupled to a drive assembly of a mobile robot. The first sensor can be configured to determine first rotation information of a wheel of the drive assembly. The system may further include a second sensor that is operatively coupled to the drive assembly. The second sensor may be configured to determine second rotation information of the wheel. The system can include a speed conversion module that is configured to receive the first and second rotation information at a first processing rate. The speed conversion module may also be configured to determine corresponding first and second speed information based on the first and second rotation information. The system can include a safety programmable logic controller (SPLC).

Abstract: A mobile robot charger can have one or more charger electrical contacts. A shroud can be movable between a closed position and an open position, and can be configured to cover the charger electrical contact(s) in the closed position and to expose the charger electrical contact(s) in the open position. The shroud can be configured to move from the closed position to the open position when the mobile robot engages the charger. A switch, such as a momentary switch, can be movable between an off position and an on position, and can be moved from the off position to the on position when the mobile robot engages the charger. One or more electromagnetic switches (e.g., reed switches) can have an on configuration and an off configuration, and can be turned to the on configuration by one or more magnets on the mobile robot when the mobile robot engages the charger.