{"id":13582,"date":"2019-04-13T11:24:15","date_gmt":"2019-04-13T01:24:15","guid":{"rendered":"http:\/\/legoeng.local\/?p=13582"},"modified":"2019-05-28T09:54:17","modified_gmt":"2019-05-27T23:54:17","slug":"linkage-warm-ups-1","status":"publish","type":"post","link":"http:\/\/legoeng.local\/linkage-warm-ups-1\/","title":{"rendered":"Linkage Warm Ups 1: LEGO Punchers and the 4-Bar Linkage"},"content":{"rendered":"<figure id=\"attachment_13583\" aria-describedby=\"caption-attachment-13583\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/LEGO-Puncher-Class.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-13583 size-full\" src=\"http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/LEGO-Puncher-Class.jpg\" alt=\"\" width=\"1024\" height=\"768\" srcset=\"http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/LEGO-Puncher-Class.jpg 1024w, http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/LEGO-Puncher-Class-300x225.jpg 300w, http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/LEGO-Puncher-Class-768x576.jpg 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption id=\"caption-attachment-13583\" class=\"wp-caption-text\">Puncher battles are fun, and guarantee that students will innovate to win<\/figcaption><\/figure>\n<p>Before attempting to build walking robots like <a href=\"http:\/\/legoeng.local\/trotbot-walking-machine\/\">TrotBot <\/a>and <a href=\"http:\/\/legoeng.local\/rapidly-prototyping-strider-ver-3-to-be-smoother-stronger-faster\/\">Strider<\/a>, we first played with linkages in a few simpler challenges like &#8220;punchers&#8221;, which utilize a 4-bar linkage to create a simple robotic arm.\u00a0 Here&#8217;s a video of my nephew Theo battling and explaining how his puncher works:<\/p>\n<p><strong><em>[Please note: Safety glasses should be worn when battling &#8211; Editor]<\/em><\/strong><\/p>\n<p><iframe loading=\"lazy\" title=\"LEGO Punchers - 4 Bar Linkage Warm Up\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/BJLoSxhVqdc?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>4-bar linkages are great for introducing students to mechanical linkages since they are relatively simple to build and understand. Plus, the low bar count means the mechanism tends to be sturdier and more efficient than mechanisms based on 6-bar or 8-bar linkages. This makes 4-bar linkages the optimal solution for many applications, such as mountain bike suspensions.<\/p>\n<p style=\"text-align: left;\">4-bar linkages can be configured in an infinite number of ways by changing the bar lengths, which can change the linkage&#8217;s behavior dramatically. Below are some of the major categories of 4-bar linkage behavior, created by re-arranging the yellow, white, orange and red bars:<\/p>\n<p><iframe loading=\"lazy\" title=\"Four Bar Linkage Configurations in LEGO Technic\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/QVKzI0XSSc0?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>You can find <a href=\"https:\/\/www.diywalkers.com\/lego-punchers-4-bar-linkage-warm-up.html\" target=\"_blank\" rel=\"noopener\">Puncher building instructions here<\/a>, along with an online simulator to test how changing the linkage&#8217;s bar lengths changes how it punches. Here is an example:<\/p>\n<figure id=\"attachment_13662\" aria-describedby=\"caption-attachment-13662\" style=\"width: 482px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/Puncher-Simulator2.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-13662 size-full\" src=\"http:\/\/legoeng.local\/wp-content\/uploads\/2019\/04\/Puncher-Simulator2.gif\" alt=\"\" width=\"482\" height=\"362\" \/><\/a><figcaption id=\"caption-attachment-13662\" class=\"wp-caption-text\">An example of the online linkage simulator<\/figcaption><\/figure>\n<p><em>[Update May 14, 2019]<\/em><br \/>\nThese punchers can also be motorized, but this requires converting the circular motion of the motor to oscillation. This can be done by programming the motor to do a partial rotation, or by adding a crank and a 6th bar to the mechanism as done in the following video.<\/p>\n<p><iframe loading=\"lazy\" title=\"Motorized LEGO Puncher\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/hdle8w80chk?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>Motorized punchers could also be added to mobile robots to create a type of &#8220;Boxing Bot&#8221;, but the robot&#8217;s frame would need to be strong enough to handle the puncher&#8217;s oscillating force. If you were to play with this idea, I recommend using shorter beams to reduce the weight and inertial forces generated by the punching action. Boxing Bots would work well as an EV3 build as\u00a0the weight of the brick would help to absorb the inertial forces.<\/p>\n<div class=\"also-in-this-series\">\n<h3 class=\"series-title\">Also in <q>DIY Walkers<\/q><\/h3>\n<ol start=\"1\">\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/diy-walkers-explorations-of-the-trotbot-walking-mechanism\/\" title=\"DIY Walkers: The TrotBot walking mechanism\">DIY Walkers: The TrotBot walking mechanism<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/diy-walkers-trotbot-using-ev3\/\" title=\"DIY Walkers: TrotBot using EV3\">DIY Walkers: TrotBot using EV3<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/diy-walkers-strider\/\" title=\"DIY Walkers: Strider\">DIY Walkers: Strider<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/ev3-trotbot-version-2-inspired-by-a-galloping-horse\/\" title=\"EV3 TrotBot Version 2: Inspired by a Galloping Horse\">EV3 TrotBot Version 2: Inspired by a Galloping Horse<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/hexapod-trotbot-a-classroom-friendly-diy-walker\/\" title=\"Hexapod TrotBot: A classroom-friendly DIY walker\">Hexapod TrotBot: A classroom-friendly DIY walker<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/diy-walkers-klanns-mechanical-spider\/\" title=\"DIY Walkers: Klann&#8217;s Mechanical Spider\">DIY Walkers: Klann&#8217;s Mechanical Spider<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/rapidly-prototyping-strider-ver-3-to-be-smoother-stronger-faster\/\" title=\"Rapidly Prototyping Strider &#8211; Smoother, Stronger, Faster\">Rapidly Prototyping Strider &#8211; Smoother, Stronger, Faster<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/linkage-warm-ups-1\/\" title=\"Linkage Warm Ups 1: LEGO Punchers and the 4-Bar Linkage\">Linkage Warm Ups 1: LEGO Punchers and the 4-Bar Linkage<\/a>\n\t\t<\/li>\n<li class=\"series-post\">\n\t\t\t<a href=\"http:\/\/legoeng.local\/linkage-warm-ups-2-lego-jumpers-and-hoppers\/\" title=\"Linkage Warm Ups 2: LEGO Jumpers and Hoppers\">Linkage Warm Ups 2: LEGO Jumpers and Hoppers<\/a>\n\t\t<\/li>\n<\/ol>\n<p><a href=\"http:\/\/legoeng.local\/series\/diy-walkers\/\">View the entire series<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Before attempting to build walking robots like TrotBot and Strider, we first played with linkages in a few simpler challenges like &#8220;punchers&#8221;, which utilize a 4-bar linkage to create a simple robotic arm.\u00a0 Here&#8217;s a video of my nephew Theo battling and explaining how his puncher works: [Please note: Safety glasses should be worn when [&hellip;]<\/p>\n","protected":false},"author":469,"featured_media":13583,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[99,502],"tags":[],"_links":{"self":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/posts\/13582"}],"collection":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/users\/469"}],"replies":[{"embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/comments?post=13582"}],"version-history":[{"count":0,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/posts\/13582\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/media\/13583"}],"wp:attachment":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/media?parent=13582"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/categories?post=13582"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/tags?post=13582"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}