Drone Flying
Posted inElectrical & Electronics Mechanical Robots

Drone Design Hands On

This post is part of the Hands on Robot Design series. See here for the full list of posts/topics http://robotsforroboticists.com/hands-on-ground-robot--drone-design-series for information on mechanical, electrical, motion control, computing, sensors, and more. The drones designed for the DARPA SubT challenge needed to be great at flying through tunnels and exploring unknown subterranean environments. The plan was to be as aggressive as…
modular robot design
Posted inMechanical

Mechanical & Wheels – Hands On Ground Robot Design

This post is part of the Hands on Ground Robot Design series. See here for the full list of posts/topics http://robotsforroboticists.com/hands-on-ground-robot--drone-design-series for information on mechanical, electrical, motion control, computing, sensors, and more. Robot Size Decision After we have the list of system requirements we start with the design of the mechanical structure of the robot. In this case we decided…
Hydraulic System
Posted inMechanical

Using Hydraulics for Robots: Introduction

Hydraulics are sometimes looked at as an alternative to electric motors. Some of the primary reasons for this include: Linear motionVery high torque applicationsSmall package for a given torqueLarge number of motors that can share the reservoir/pump can increase volume efficiencyYou can add dampening for shock absorption However there are also some downsides to using hydraulics including: More parts are…
fstab options for mounting drive
Posted inComputing & Networking Mechanical

How to Mount an External Removable Hard Drive on a Robot

We often want to add an external hard drive to our robots in order to have a dedicated drive for data collection. Having the dedicated drive lets the primary drive remain uncluttered, have less wear-and-tear, split logging between drives for performance, and potentially be a larger spinning disk (as opposed to an expensive SSD). It is also useful when the…
Bearings, Bushings & The Engineering Commons
Posted inMechanical

Bearings, Bushings & The Engineering Commons

I listen to several podcasts, including The Amp Hour, Embedded, and the Engineering Commons. A recent (depends when you read this) Engineering Commons podcast was all about bearings. I have been wanting to write a bearings post for a while so I am using their podcast (with permission) as a basis for writing this post. Much of this post will…
tether
Posted inMechanical

Tether’s: Should Your Robot Have One?

Some people swear that all tethers are bad. Some people recommend attaching a tether to robots in order to provide power (to save the mass and volume of the batteries), for reliable fast communications, transfer of pressure or fluid, to track a robots position, or as a safety harness (in case the robot needs to be dragged out). However before…
Marsokhod 6x6 is completely articulated in pitch, roll and yaw.
Posted inMechanical

Drive Selection – Wheels, tracks and more

In the past we have looked at wheel design and the kinematics of skid steer and mecanum wheels. In this post we will take a quick look at different types of mobility types (ie. wheels, tracks, and how to connect them) for drive selection. I know the items in this list are not direct comparisons. For example listing rocker bogie…
grease gun
Posted inMechanical

Lubrication: Dry vs Wet – Oil vs Grease

One thing that is often looked is lubrication (lube). Changing your lubrication and selecting the proper type can dramatically modify the performance of your system. This change of lubrication was one of the primary reasons MSL was delayed from launching to Mars. Improper lubrication can cause your mechanical parts to wear out and fail. It can also lead to annoying…
quadrature encoder
Posted inElectrical & Electronics Mechanical Systems & Sensors

Incremental Encoder Selection

Hi all Just a quick post on incremental encoders. Incremental encoders are good for speed control and can be used for position control when we have a homing routine to get absolute position, or the system is constrained to less than one rotation. One way an incremental encoder can also be an absolute encoder is if it is single turn.…
LRV Wheel
Posted inMechanical

Wheel & Grouser Design

For many robots the wheels are an afterthought however they are essential for letting the robot drive around. Another thing that is often neglected is choosing the proper grousers for your wheel. Most of the design parameters for wheels and grousers are based on experience, intuition (which may or may not be correct) and qualitative assessments. Serious wheel design is…
thermal design
Posted inMechanical

Mechanical Tolerancing

Hi all I do not have much to say here except I have seen many cases where tolerancing was wrong in mechanical parts. A general rule is that if you need to assemble parts with a hammer since you can not slide them in your self, it is not correctly toleranced and can cause problems later on. Also if you…
brushless motor
Posted inElectrical & Electronics Mechanical

Motors and Feedback (encoders)

Hi all There are many types of motors and feedback methods to choose from. Which do you need? Keep reading to find out more about selecting your motor stackup. Since most field robots are DC powered I am skipping the many types of AC motors that are out there. In addition to this post you can find out all about…