{"id":583,"date":"2016-12-16T19:36:40","date_gmt":"2016-12-16T19:36:40","guid":{"rendered":"http:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/?page_id=583"},"modified":"2017-04-08T03:41:29","modified_gmt":"2017-04-08T03:41:29","slug":"package-drop-mechanism","status":"publish","type":"page","link":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/system-implementation-full-system-and-subsystems\/sound-detection-package-drop-payload\/package-drop-mechanism\/","title":{"rendered":"Package Drop Mechanism"},"content":{"rendered":"<p>Subsystem Requirements:<\/p>\n<p><span style=\"font-weight: 400\">To effectively fulfill the mandatory system functional requirements, our package drop mechanism is required to meet the following basic requirements:<\/span><span style=\"font-weight: 400\"><br \/>\n<\/span><span style=\"font-weight: 400\">The mechanism should:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Be able to carry a 100g package<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Enable easy package attachment<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Have a good grip on the package throughout the flight<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Release the package easily without causing any damage<\/span><\/li>\n<\/ul>\n<p><strong>FVE Demo: Flight with package and package drop:<\/strong><\/p>\n<p><iframe loading=\"lazy\" width=\"1170\" height=\"658\" src=\"https:\/\/www.youtube.com\/embed\/q3KJjAxOeWA?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe><\/p>\n<p><span style=\"text-decoration: underline\"><em>Nov 30, 2016<\/em><\/span><\/p>\n<p><strong>Testing<\/strong><\/p>\n<p><span style=\"font-weight: 400\">Rigorous testing was done to ensure that the mechanism worked, as required. A package weighing ~160 g and dimensions 10cm x 10 cm was made for this testing. Typically, two types of tests were done to ensure good performance:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400\"><b>In-flight testing:<\/b><span style=\"font-weight: 400\"> Package was attached to the drone and the drone was flown at speeds reaching up to 3 m\/s. This test was conducted 5-6 times. This test not only ensured us of the grip of the mechanism but also of the stability of the flight with the package<\/span><\/li>\n<\/ol>\n<ol>\n<li style=\"font-weight: 400\"><b>Attach\/release testing:<\/b><span style=\"font-weight: 400\"> Ease of package attachment and release was tested by performing this sequence 20-25 times<br \/>\n<\/span><\/li>\n<\/ol>\n<p><iframe loading=\"lazy\" width=\"1170\" height=\"658\" src=\"https:\/\/www.youtube.com\/embed\/Jc0DYnPrHLo?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<p><span style=\"text-decoration: underline\"><em>Nov 26, 2016<\/em><\/span><\/p>\n<p><strong>Design Implementation<\/strong><\/p>\n<p><span style=\"font-weight: 400\">The mechanism is basically a slider-crank mechanism mounted on a 3-D printed ABS body, facilitating required motion of the slider. Various components of the mechanism are highlighted in Figure 3.<\/span><\/p>\n<p style=\"text-align: center\"><span style=\"font-weight: 400\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-636\" src=\"http:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels.png\" alt=\"mechanism-photo-with-labels\" width=\"600\" height=\"228\" srcset=\"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels.png 937w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-300x114.png 300w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-768x292.png 768w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-700x266.png 700w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-520x198.png 520w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-360x137.png 360w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-250x95.png 250w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/Mechanism-photo-with-labels-100x38.png 100w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/span><span style=\"font-weight: 400\">Figure 4:\u00a0Final fabricated Package Drop mechanism<br \/>\n<\/span><\/p>\n<p><span style=\"font-weight: 400\">The mechanism consists of the following main components:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Servo motor: To actuate the mechanism<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Servo motor attachment: acts as the crank<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Connecting rod: 3-D printed (ABS); to connect crank with slider<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Slider rod: made of wood to keep it lightweight while providing sufficient strength<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Body: 3-D printed (ABS); to provide mounting for the servo motor, passage for the slider rod, and space for attaching a package to the mechanism<\/span><\/li>\n<\/ol>\n<p>Control of the mechanism for FVE was implemented using a Raspberry Pi mounted on the drone. Raspberry Pi and its housing are shown in Figure 3. We created a server on Raspberry Pi and sent HTTP calls to it, with required servo angle as the parameter, using a phone. Raspberry Pi, in turn, commanded the servo motor to rotate by the specified angle to open\/close the mechanism.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-640 size-large\" src=\"http:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-1024x376.jpg\" alt=\"rpi-housing\" width=\"640\" height=\"235\" srcset=\"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-1024x376.jpg 1024w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-300x110.jpg 300w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-768x282.jpg 768w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-700x257.jpg 700w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-520x191.jpg 520w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-360x132.jpg 360w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-250x92.jpg 250w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing-100x37.jpg 100w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/rpi-housing.jpg 1227w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><\/p>\n<p style=\"text-align: center\">Figure 5: (a) Raspberry Pi used to command the mechanism, (b) Housing for Power supply and Raspberry Pi<span style=\"font-weight: 400\"><br \/>\n<\/span><\/p>\n<p><span style=\"text-decoration: underline\"><em>Nov 22, 2016<\/em><\/span><\/p>\n<p><strong>Final Design<\/strong><\/p>\n<p>We went over one more design which is <strong>much simpler, compact and does not depend on motor\u2019s torque for locking the package. <\/strong><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-628 aligncenter\" src=\"http:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-300x169.png\" alt=\"pd_design-2\" width=\"450\" height=\"253\" srcset=\"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-300x169.png 300w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-768x432.png 768w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-1024x576.png 1024w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-700x394.png 700w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-520x293.png 520w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-360x203.png 360w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-250x141.png 250w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2-100x56.png 100w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-2.png 1370w\" sizes=\"auto, (max-width: 450px) 100vw, 450px\" \/><\/p>\n<p style=\"text-align: center\">Figure 2: SolidWorks model for simple servo-driven pin lock for hanging a package<\/p>\n<p>With this design, there is a concern of the hanging package affecting our drone\u2019 dynamics.\u00a0 But since our package has to weigh just 100g, we don\u2019t think it will be much of an issue. For now, we are going with this design and will start fabricating it. Flight-testing with the mechanism might change our decision later. Figure 2 shows the SolidWorks model.<\/p>\n<p><span style=\"text-decoration: underline\"><em>Nov 19, 2016<\/em><\/span><\/p>\n<p><strong>Initial Design<\/strong><\/p>\n<p>Inspired by the &#8220;double-door opening&#8221;\u00a0mechanism used by Amazon on one of their package delivery drone&#8217;s prototypes, we came up with a single door design for our mechanism.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-622\" src=\"http:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1.jpg\" alt=\"pd_design-1\" width=\"1200\" height=\"320\" srcset=\"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1.jpg 1406w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-300x80.jpg 300w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-768x205.jpg 768w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-1024x273.jpg 1024w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-700x187.jpg 700w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-520x139.jpg 520w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-360x96.jpg 360w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-250x67.jpg 250w, https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-content\/uploads\/sites\/17\/2016\/12\/PD_Design-1-100x27.jpg 100w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<p style=\"text-align: center\">Figure 1: Initial design of Package drop mechanism (a) Single-door opening mechanism actuated by a servo motor, (b) Resultant SolidWorks assembly with mount for Matrice 600 (sponsor&#8217;s drone), (c) Assembly mounted on Matrice 600<\/p>\n<p>The design developed, shown in Figure 1 above, has the following advantages:<\/p>\n<ol>\n<li>Flexible, to an extent, in terms of allowed package dimensions<\/li>\n<li>Ease of loading: You just need to place the package inside from the front door (not shown in the model) and tighten the straps (not shown in the model). The straps will go over the package and would be tightened from outside.<\/li>\n<li>Firm grip over the package: With the straps, the package would be tied to its position and thus, not move inside the box, preventing any effect on the drone\u2019s dynamics<\/li>\n<\/ol>\n<p>But this design has some disadvantages too:<\/p>\n<ol>\n<li>The door has to be held closed by the servo motor\u2019s torque, which is a little bit of risk. It would have been better if the lock was some physical structure rather than the torque applied by the motor<\/li>\n<li>The mechanism is a bit bulky (mainly because of the box) and still not very easy to fabricate<\/li>\n<\/ol>\n<p style=\"text-align: left\">\n","protected":false},"excerpt":{"rendered":"<p>Subsystem Requirements: To effectively fulfill the mandatory system functional requirements, our package drop mechanism is required to meet the following basic requirements: [&hellip;]<\/p>\n","protected":false},"author":81,"featured_media":0,"parent":588,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-583","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/pages\/583","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/users\/81"}],"replies":[{"embeddable":true,"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/comments?post=583"}],"version-history":[{"count":12,"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/pages\/583\/revisions"}],"predecessor-version":[{"id":603,"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/pages\/583\/revisions\/603"}],"up":[{"embeddable":true,"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/pages\/588"}],"wp:attachment":[{"href":"https:\/\/mrsdprojects.ri.cmu.edu\/2016teamf\/wp-json\/wp\/v2\/media?parent=583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}