Seite - 59 - in Proceedings of the OAGM&ARW Joint Workshop - Vision, Automation and Robotics

Fig. 3. Mapping results a) small indoor rooms b) disrupted map in a big open area at ELROB 2016 Fig. 4. Xbox Controller for operating the robot buttons are used for steering the robot. The following table II shows which of them are implemented for which function. TABLE II XBOX BUTTON CONFIGURATION Button Function Left joystick (up/down) Drive (forward/backward) Left joystick (left/right) Rotate (left/right) Right joystick (up/down) Height-adjustment rubber tracks (up/down) Right bumper Release button Left bumper Turbo button Due to safety reasons the enable button have to be pressed all time for steering the robot by the joystick. Speed can be controlled depending on how strong the stick gets pushed. That means if the joystick gets only half pushed, the robot will also drive with half the speed. Alternatively, the left bumper can be used for enable the robot’s full speed mode. In this mode, Robbie drives with around 5km/h full speed. As mentioned before, it is possible to overcome obstacles by adjusting the robot’s rubber tracks up or down. This is done by moving the right joystick up or down respectively. Safety state is achieved when all buttons are not pressed. IV. RESULTS AND DISCUSSION Compared to the keyboard variant, the Xbox controller is the better decision for operating the robot in all ELROB challenges. The results of both variants compared are shown in Table III. While the Xbox controller obtains mostly excellent results, the keyboard is improvable in most criteria. Since all buttons of the keyboard are closely packed together, steering the robot becomes more complex. Moreover delay times of the sent commands were detected during tests with the keyboard, which also effects sensitivity and accuracy of steering the robot. Additionally, increasing speed by the keyboard needs to push and hold one ”drive-button” and push the ”speed-up-button” at the same time. In contrast, the Xbox controller varies speed by inclining the joystick, which results to more sensitivity and accuracy. TABLE III EVALUATION OF BOTH STEERING VARIANTS (+ ... EXCELLENT,∼ ... AVERAGE,• ... BAD) Evaluation Criteria Keyboard Xbox Controller Handling ∼ + Accuracy • + Sensitivity • + Flexibility ∼ ∼ Feasability + + Safety functions + + Mainly, there are several aspects coming out of this development.The tele-operatedoperationwasagreat success at the ELROB event. While the video stream is slightly delayed due to transfer limitation, the analogue joysticks are 59