Autonomous Street Sweepers, aka Roomba for Public Works
I recently attended a Nashville WalknBike outreach event where the city presented their proposal for bike and sidewalk infrastructure development to meet the needs of our rapidly growing population. One of the key takeaways from the meeting is that there is a need for effective, inexpensive street cleaning.
The “state of the art” in street cleaning today for bike lanes are smaller and narrower versions of existing street cleaning vehicles. These vehicles typically cost in the $100-200k range and require one or two human operators. PeopleForBikes has done an excellent survey of the options available for public works departments. Some cities, such as Los Angeles, are testing smaller vehicles (Advance SW8000) which may be a better fit for tight bike lanes.
Sidewalks and bike lanes are an obvious and excellent application for autonomous, electric sweepers. Moving away from a human-crewed cabin vehicle gives you a long list of advantages:
- increased bin size: no need for a human operator, cab, HVAC; the majority of the vehicle volume and cargo payload can be devoted to the debris bin
- decreased vehicle size: no crew requirements removes need for vehicle to be car-sized
- improved flexibility: a larger fleet of smaller vehicles can potentially service streets, bikeways, sidewalks, alleys that a conventional crewed vehicle would not be able to access
- lower road damage: road impact typically rises exponentially with the weight of the vehicle, especially true for sidewalks and bike lanes that may not be suitable for heavy vehicles
- more frequent schedule: no need for a human operator => more frequent cleaning cycles or more coverage per vehicle
- data collection: more frequently serviced routes with sensor-laden robots allows for lots of data to be collected about surface condition: litter frequency, damaged bollards pylons and other road wear, vehicle debris or vehicles parked in the lane, etc
- cost of operations: cost of operations drops by an order of magnitude given reduced salary requirements, less expensive “fuel”, lower maintenance requirements
- decreased operation obtrusiveness: decreased vehicle noise means less annoyance to those nearby, may extend acceptable hours of operation
- fixed routes: predictable routes are perfectly suited for sizing battery capacity to application requirements
Surprisingly a brief search does not turn up any existing commercial offerings of autonomous street sweepers. Design concepts exist – like the Scarab concept by Olga Kalugina – but so far remain thought exercises only.
It’s also worth noting that new capabilities do not necessarily eliminate jobs, but could be viewed as a force multiplier for existing service personnel. Depending on application, if the vehicles are not road-worthy it may make sense for humans to transport and deploy these bots during their cleaning cycle, allowing for more specialized bots without high-speed operations requirements. Additionally, some areas will simply be a better serviced by humans and existing sweeper equipment than by autonomous sweepers – the target is the majority of the street cleaning need that can be serviced by autonomous sweepers today, instead of more general-purpose and significantly more complicated cleaning robot.