Nomad | ZAPT's Autonomous Lawn Mower
Works Where Other Autonomous Mowers Do Not
How Nomad maintains a constant knowledge of its location through GNSS and imagery to improve productivity
Nomad Autonomous Lawn Mower Specs
60” tri-blade mulching deck
Min Width for Access
31.5” (clear 36” gate) Skinny mode
Turf tire - 18 x 8.5 all-wheel drive & all-wheel steer
15 ° operational, slow transit 25 ° (in Fat mode)
1.5” - 5.5” in 0.25” increments
Quad SIM, Dual Band Radio GSM, WIFI
How It Works
Nomad autonomously cuts grass within a defined boundary based on a pre-determined path. The defined boundary is established initially from satellite imagery data. Then while in operation, Nomad will collect real-time positioning and mapping data from its redundant sensor suite onboard. These sensors construct an accurately scaled map with detailed imagery within 100 meters around Nomad as it moves along the path. This map is then used to augment Nomad's information for future work. Nomad's path planning algorithm is also used to safely navigate around all unexpected moving or stationary objects along its route. Essentially, we set up a path to be cut on your site, load that path into Nomad, and then Nomad will do the rest, keeping you updated along the way.
There is redundancy and reliability built-in at every level in Nomad because our fundamental focus is safety. Nomad has interconnected sensors to always know the relative speed and distance of any detected objects at all times. Essentially, Nomad never relies on one sensor to operate. Suppose an object comes too close to Nomad while working. In that case, it immediately shuts down, alerts monitoring users, and stops all movement until further directed or until the object moves to a safe distance. On top of redundant sensors, Nomad has multiple control options and emergency stop systems for additional user oversight. Bottom-line, Nomad is designed to be unquestionably safe, proven through extensive testing of its software, hardware, and integrated systems.
Nomad maximizes productivity by constantly knowing its location, mowing at an optimal speed with minimal overlap, and transforming deck sizes to mow complex areas. Nomad also has 4-wheel drive and 4-wheel steering to maintain productivity on slopes and cut while moving in any direction. Initially, we will use the path planning software to optimize the most efficient mowing path on the site. Then while mowing, Nomad will optimize its path considering objects it detects. Additionally, Nomad has an extensive reporting system for users to evaluate efficiency, create improved schedules, and be proactive with regular maintenance. We generate at least four mowing paths for each site, so we do not compact the soil and leave tire tracks due to mowing the same path week after week.
Starting with the first sensor, Nomad utilizes one of the most widely used positioning tools, GNSS (GPS). Nomad receives signals from multiple satellite constellations adding reliability over just using GPS. Nomad's position is precisely determined using time of arrival data from the satellites and precise corrections. For areas where satellite data is blocked, such as under trees and along large fences or walls, Nomad continues to precisely navigate using LiDAR by matching the point cloud seen in real-time with a stored "map." This form of map matching delivers very accurate positioning without GNSS.
Coupled with GNSS and LiDAR, Nomad relies on several integrated sensors to stay on the path, avoid collisions and objects, and maintain safe operations. These sensors include inertial navigation sensors (IMU), visual sensors (stereo cameras), ultrasonic sensors, and resolvers/encoders. An IMU measures rotational rate and accelerations to compute position when aided with other sensors. The stereo cameras and LiDAR identify objects while Nomad is operating. Most will be "known" objects already mapped within Nomad, and some will be "unknown" objects. Additionally, depth is detected to objects to aid navigation from the stereo cameras. The ultrasonic sensors detect close-range objects, and the wheels' resolvers monitor steering and traction within the challenging terrain. These redundant sensors are integrated to ensure safe and reliable autonomous operations.