Perching on a vertical surface carries the risk of severe damage to the vehicle if the maneuver fails, especially if failure goes undetected. We present a detection method using an onboard 3-axis accelerometer to discriminate between perching success and failure. An analytical model was developed to calculate acceleration differences for success and failure and set decision times. Two distinct decision times were shown to be effective, corresponding to properly engaging the gripper and overloading the gripper's capabilities. According to a machine learning feature selection algorithm, the maximum Z axis acceleration of the quadrotor and the presence of near-zero readings are the most relevant features within these two time frames. Using these features, the detection algorithm discriminated between success and failure with a 91% accuracy at 40 ms, and 94% at 80 ms. Real-time detection and failure recovery experiments with a 20 g quadrotor verify the detection method. An improved approach that combines various decision times correctly identified success/failure for all 20 trials with an average total falling distance of 0.8m during recovery. We discuss the feasibility of extending our method to other quadrotor platforms.

This is a pilot study of an instructional technique that teaches important solid mechanics concepts within the context of an entrepreneurship case study and lab. Students were tested pre-and-post the case study/lab experiences to determine changes in engineering and entrepreneurial content knowledge, entrepreneurial self-efficacy and career intent. Results show that students can increase their knowledge of targeted entrepreneurship concepts without diminishment of learning core engineering concepts. While the case study experience did not significantly change entrepreneurial career intentions it did grow students' perceived entrepreneurial self-efficacy (as measured by confidence in business skills), which can be a precursor to changing career intent. The case study experience also appealed to a broad spectrum of students with career interests ranging from working for a start-up to working for an established global business. The implications of entrepreneurial case study instruction are discussed.