FIELD OF THE INVENTION

This subject invention relates to robots, preferably an autonomous garden weeding robot.

BACKGROUND OF THE INVENTION

Weeds reduce yields because they steal water, nutrients, and sunlight from food crops. This represents a significant challenge to all growers. One source states, “Currently, weed control is ranked as the number one production cost by organic and many conventional growers” seeFundamentals of Weed Science,4thedition,Robert L. Zimdahl, page 308 incorporated herein by this reference. Furthermore, the weed problem is worsening as weeds become resistant to common herbicides. See https://en.wikipedia.org/wiki/Glyphosate incorporated herein by this reference.

Mechanical eradication of weeds would solve the problem of herbicide resistance. Accordingly, this strategy has been pursued by many. See, for example, http://www.bosch-presse.de/presseforum/details.htm?txtID=7361&tk_id=166, incorporated herein by this reference. The challenge is constructing cost-effective implements able to discriminate between weeds and desired crops. Purely mechanical methods are available commercially (see, e.g. http://www.lely.com/uploads/original/Turfcare_US/Files/WeederSpecSheet_FINAL.pdf. incorporated herein by this reference) but are limited in scope. Vision-based methods have not yet proven commercially successful possibly because of the great similarity between weeds and crops during some parts of the growth cycle. See also U.S. Published Patent Application Serial No. 2013/0345876 and U.S. Pat. Nos. 5,442,552 and 8,381,501 all incorporated herein by this reference.

BRIEF SUMMARY OF THE INVENTION

The present invention offers a mechanical eradication method directed by sensors able to discriminate between weeds and crops and does so preferably without resort to computer vision. Instead it uses highly reliable but extremely low-cost sensors arranged in a particular way.

Featured is a weeding robot comprising a chassis, a motorized cutting subsystem, and a drive subsystem for maneuvering the chassis. A weed sensor subsystem on the chassis is at a first elevation from the ground. A crop/obstacle sensor subsystem on the chassis is at a second, higher elevation from the ground. A controller subsystem is responsive to the weed sensor subsystem and the crop/obstacle sensor subsystem and is configured to: control the drive subsystem to maneuver the chassis about a garden, upon detection of a weed, energize the motorized cutting subsystem to cut the weed and upon detection of a crop or obstacle, control the drive subsystem to maneuver the chassis away from the obstacle. Preferably the controller subsystem is further configured to de-energize the motorized cutting subsystem after the chassis has moved a predetermined distance and/or after a predetermined period of time. The controller subsystem is preferably further configured to maneuver the chassis about the garden in a random or deterministic pattern.

The weeding robot may further include at least one battery carried by the chassis for powering the motorized cutting subsystem and the drive subsystem and at least one solar panel carried by the chassis for charging the at least one battery. The controller subsystem may further be configured to de-energize the drive subsystem when the battery power is below a predetermined level.

In one example, the motorized cutting subsystem includes a motor proximate the front of the chassis with a shaft carrying a string rotated below the chassis. In one example, the drive subsystem includes four motorized wheels. Preferably, the weed sensor subsystem may include at least one capacitance sensor located under the front of the chassis and the crop/obstacle sensor subsystem includes right and left forward mounted capacitance sensors. The capacitance sensors may be capaciflector proximity sensors.

Also featured is an autonomous weeding robot comprising a chassis, a battery, at least one solar panel on the chassis for charging the battery, a motorized cutting subsystem powered by the battery, and a drive subsystem for maneuvering the chassis and powered by the battery. At least one capacitance weed sensor is located under a forward portion of the chassis and at least one crop/obstacle capacitance sensor is located on the forward portion of the chassis. A controller subsystem, responsive to the capacitance weed sensor and the capacitance crop/obstacle sensor is configured to: control the drive subsystem to maneuver the chassis about a garden, upon detection of a weed, energize the motorized cutting subsystem to cut the weed, de-energize the motorized cutting subsystem after the chassis has maneuvered a predetermined distance and/or after a predetermined period of time, and upon detection of a crop or obstacle, control the drive subsystem to maneuver the chassis away from the obstacle.

Also featured is a garden weeding method comprising equipping an autonomous robot with a motorized cutting subsystem, maneuvering the robot about a garden, detecting a weed, upon detection of the weed, energizing the motorized cutting subsystem to cut the weed, detecting a crop or obstacle, and upon detection of the crop or obstacle maneuvering the robot away from the obstacle. The method may further include de-energizing the cutting subsystem after the robot has moved a predetermined distance and/or after a predetermined period of time.

The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.

