{"id":87,"date":"2009-12-20T22:46:06","date_gmt":"2009-12-21T03:46:06","guid":{"rendered":"http:\/\/ammonsengineering.com\/blog\/?p=87"},"modified":"2009-12-20T22:46:06","modified_gmt":"2009-12-21T03:46:06","slug":"calculations","status":"publish","type":"post","link":"https:\/\/ammonsengineering.com\/blog\/2009\/12\/calculations\/","title":{"rendered":"Calculations"},"content":{"rendered":"<p>When I picked out all the hardware during the design phase, I didn&#8217;t really explain any of my calculations.\u00a0 Here are a few numbers of interest:<\/p>\n<h3>Encoder calculations<\/h3>\n<p>I decided I wanted encoders with a minimum resolution of 1000 pulses\/rev.\u00a0 With quadrature\u00a0 counting, that gives me 4000 counts\/rev.\u00a0 For the pendulum, this makes the resolution 0.09 degrees\/count (or 0.00157 radians\/count for those that care).\u00a0 For position measurement, the 1.25&#8243; diameter gear on the encoder gives a position resolution of 0.00098 inches\/count or 0.0249 mm\/count.\u00a0 These resolutions should\u00a0give adequate feedback even when the speeds are fairly slow.<\/p>\n<h3>Motor calculations<\/h3>\n<div id=\"attachment_89\" style=\"width: 414px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/ammonsengineering.com\/blog\/wp-content\/uploads\/2009\/12\/IG32P-Graph.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-89\" class=\"size-full wp-image-89\" title=\"IG32P Motor Performance Chart\" src=\"http:\/\/ammonsengineering.com\/blog\/wp-content\/uploads\/2009\/12\/IG32P-Graph.png\" alt=\"IG32P Motor Performance Chart\" width=\"404\" height=\"215\" srcset=\"https:\/\/ammonsengineering.com\/blog\/wp-content\/uploads\/2009\/12\/IG32P-Graph.png 404w, https:\/\/ammonsengineering.com\/blog\/wp-content\/uploads\/2009\/12\/IG32P-Graph-150x79.png 150w, https:\/\/ammonsengineering.com\/blog\/wp-content\/uploads\/2009\/12\/IG32P-Graph-300x159.png 300w\" sizes=\"auto, (max-width: 404px) 100vw, 404px\" \/><\/a><p id=\"caption-attachment-89\" class=\"wp-caption-text\">IG32P Motor Performance Chart<\/p><\/div>\n<p>I started selecting a motor by figuring out what the power limitations were.\u00a0 From the beginning I planned on using the NI 9505 module, which has a limit of 30V and 5A.\u00a0 I decided to use a 24V motor since that is a standard voltage and there are a large number of robot motors available that use 24V.\u00a0 The motor I picked is 24V with a stall current of 5A.\u00a0 The motor (without gearbox) has a maximum speed of 6000 RPM and a stall torque of about 1900 g-cm (0.186 N-m) according to the chart above.\u00a0 There were several gearbox combinations available, so I picked the 19:1 ratio that will give me fairly high stall torque of\u00a03.54 N-m.\u00a0 With an approximate total cart and pendulum mass of 1.4 kg and a moment arm of 1&#8243; (gear radius), the max acceleration of the cart will be 99 m\/s^2.\u00a0 However, this drops off\u00a0quickly with speed.\u00a0 Other factors (cable carrier, support platform) will probably limit the acceleration to 50 m\/s^2 or so.\u00a0 With the 2&#8243; gear, the maximum speed is 33 inches\/sec (84 cm\/sec) and will be fast enough to travel the length of the track in about 1.5 seconds.\u00a0 If the max speed isn&#8217;t high enough, I will look into getting the 14:1 gearbox, which would reduce the torque a little bit and increase the speed.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>When I picked out all the hardware during the design phase, I didn&#8217;t really explain any of my calculations.\u00a0 Here are a few numbers of interest: Encoder calculations I decided I wanted encoders with a minimum resolution of 1000 pulses\/rev.\u00a0 With quadrature\u00a0 counting, that gives me 4000 counts\/rev.\u00a0 For the pendulum, this makes the resolution [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-87","post","type-post","status-publish","format-standard","hentry","category-hardware"],"_links":{"self":[{"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/posts\/87","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/comments?post=87"}],"version-history":[{"count":5,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/posts\/87\/revisions"}],"predecessor-version":[{"id":93,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/posts\/87\/revisions\/93"}],"wp:attachment":[{"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/media?parent=87"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/categories?post=87"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ammonsengineering.com\/blog\/wp-json\/wp\/v2\/tags?post=87"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}