The Applications of Sensor Technology in the Design of the Autonomous Robotic Lawn Mower Andrew Ragonese and Jacqueline Marx Reinventing the Lawn Mower Electromagnetic Sensors Obstacle Avoidance System Social Impact and Sustainability Using GPS to Improve Efficiency Ultrasonic SensorsInfrared SensorsMultisensor System Detect the radiation given off by an object to determine the distance from obstacles Detect sudden increases in temperature Accurate within 20 centimeters Possible issues: - Inability to detect gradual changes in temperature The combination of ultrasonic and infrared sensors in the robotic lawn mower is key to its functionality Guards against the possibility that one type of sensor may malfunction Improves the range over which the sensors can operate Mowing the lawn is often considered the most detested of all household chores. It is also a dangerous and wasteful process when conventional methods are employed, making lawn mowing an ideal application for robotic technology. The first robotic lawn mower designed for domestic use was manufactured by the Husqvarna Group in Since then, many more companies have entered the business as popularity expanded, although all of their products have the same basic design and have similar appearances to the one shown below. Robotic lawn mowers are powered by rechargeable batteries and are lightweight, safe, and efficient. While gas powered lawn mowers can consume fuel at rates upwards of 5000 watts and be as loud as a motorcycle, robotic lawn mowers typically operate at 20 to 30 watts and are 1000 times quieter than traditional systems. This near silence can be primarily attributed to the unique cutting system of the robot, consisting of small blades secured to a rapidly spinning disc housed far within the boundaries of the machine. Above all, however, the numerous sensors incorporated into the mower’s design are the greatest contributors to its autonomy and sustainability. The Boundary WireThe Sensor Most robotic lawn mowers use a boundary wire to determine the perimeter of the lawn Either stapled to the lawn or buried underground Connected to the robot’s base charging station Induced current produces a magnetic field Two emitter plates with current carrying wires produce magnetic fields that interact with the field produced by the boundary wire Interference between the fields rotates the plates of the emitter Produces sine and cosine signals that indicate the robot’s orientation and distance from the edge of the lawn The figure below illustrates that the majority of people would be comfortable owning a robotic lawn mower even if they may not be able to afford it in the current price range of $1500 to $5000. As robotic technology expands and the product becomes more popular, increased mass production will lead to lower costs and improved economic sustainability. Husqvarna. (2013) Y. Lin. United States Patent and Trademark Office. (2014) American Society of Mechanical Engineers. (2013) Z. Zhang, F. Ni, Y. Dong, M. Jin, H. Liu. Sensors and Actuators A: Physical. (2013) C. Ming, F. Bo IEEE International Conference of Robots and Biomimetics. M. Wasif th International Conference on Emerging Technologies. V. Mitokostas. Worcester Polytechnic Institute. (2008) Even with decreasing costs, the robotic lawn mower is most sustainable in the way that it improves the quality of life for humans without compromising the environment. This effect is primarily dependent on the sensor technology that makes the robotic lawn mower remarkably safe and efficient. Today, robotic lawn mowers offer a great benefit to people who lack the time, effort, or physical ability to mow their lawn themselves. Although they are most popular in Europe, robotic lawn mowers are making science fiction a reality for consumers around the world. Current ProblemsThe Solution Robot moves in random motions to mow the lawn Many areas of the lawn are mown multiple times Inefficient use of time and fuel Boundary wire is required GPS unit tracks the robot’s location in the lawn in real time Determines the edge of the lawn after being manually guided around its perimeter The robot follows a loop around the perimeter of the lawn and continues in a spiral motion toward the center No boundary wire necessary