This paper presents the design and implementation of a robotic lawnmower. The objective is to build a lawnmower with the ability to mow grass in a specified area autonomously while avoiding collisions with obstacles. The obstacles to be taken into consideration are: a flower bed, a fenced area, and a moving obstacle that will engage the lawnmower for thirty seconds and then move off of the field. The main tasks to be achieved are to create a frame of the lawnmower, select the proper wheel motors, integrate off the shelf sensors, and implement control algorithms for the motors. The aim is to design a functional and efficient navigational algorithm which is able to process data from a differential GPS, a digital IMU, ultrasonic sensors, a touch sensor, and a laser range finder (LRFS). The LRFS is the main sensor to detect and avoid moving and static obstacles. A touch sensor is also used to travel a curved path using force control. All sensors send information to a laptop computer that carries out a navigation algorithm allowing it to make decisions and direct the motors accordingly. The output of the algorithm controls the speed and direction of the mower through the use of wheel encoders.
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