{"id":11854,"date":"2016-12-28T04:45:41","date_gmt":"2016-12-27T17:45:41","guid":{"rendered":"http:\/\/legoeng.local\/?p=11854"},"modified":"2017-02-07T16:39:15","modified_gmt":"2017-02-07T05:39:15","slug":"diy-walkers-trotbot-using-ev3","status":"publish","type":"post","link":"http:\/\/legoeng.local\/diy-walkers-trotbot-using-ev3\/","title":{"rendered":"DIY Walkers: TrotBot using EV3"},"content":{"rendered":"<p>In my <a href=\"http:\/\/legoeng.local\/diy-walkers-explorations-of-the-trotbot-walking-mechanism\/\">previous post<\/a>, I shared some of my exploration of walking mechanisms using mainly LEGO Technic.<\/p>\n<p>Here is a MINDSTORMS EV3 version I have just built.<\/p>\n<p><iframe loading=\"lazy\" title=\"EV3 TrotBot, ver 1\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/DpxVmKEYgpg?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>The challenge with this build was maximizing performance while working with the heavy EV3 brick. I found that I could improve performance by adding &#8220;retractable toes&#8221; that increase foot-contact with the ground, but I had to saw 32 LEGO parts in half to make them. Instead, I looked at video of the gait in slow motion where it was obvious that the plastic LEGO axles were twisting a lot, and delaying the leg motion. I replaced the plastic LEGO axles with steel axles that I bought\u00a0from <a href=\"https:\/\/www.bricklink.com\/store\/home.page?p=Eezo#\/shop?o={&quot;showHomeItems&quot;:1}\">Brick Machine Shop<\/a>, resulting in the performance seen in the above video.<\/p>\n<p>To get an idea of how much LEGO plastic axles twist under torque I set up this simple experiment:LEGO plastic axles:<\/p>\n<p><iframe loading=\"lazy\" title=\"LEGO axles twisting under torque\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/CM4-uR84eCg?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>Stainless steel axles:<\/p>\n<p><iframe loading=\"lazy\" title=\"Steel LEGO axles resist twisting\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/3ae7WpwVff0?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n<p>I posted instructions on how I built my EV3-based TrotBot <a href=\"https:\/\/www.diywalkers.com\/mindstorms-trotbot.html\">here<\/a>. \u00a0I hope you find this useful!<\/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>In my previous post, I shared some of my exploration of walking mechanisms using mainly LEGO Technic. Here is a MINDSTORMS EV3 version I have just built. The challenge with this build was maximizing performance while working with the heavy EV3 brick. I found that I could improve performance by adding &#8220;retractable toes&#8221; that increase [&hellip;]<\/p>\n","protected":false},"author":591,"featured_media":11855,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[99,502],"tags":[132,131,559],"_links":{"self":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/posts\/11854"}],"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\/591"}],"replies":[{"embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/comments?post=11854"}],"version-history":[{"count":0,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/posts\/11854\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/media\/11855"}],"wp:attachment":[{"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/media?parent=11854"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/categories?post=11854"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/legoeng.local\/wp-json\/wp\/v2\/tags?post=11854"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}