Help with basic robotic arm

Community General Discussions
1

I am a mechanical engineering student and was assigned a design project requiring me to build something that would lift a cup of water from a bedside table and deliver it to the mouth (a straw can be used) for a patient in a hospital to drink. I am new to robotics and was hoping to recieve some direction from a little more experierenced tinkerers.

2 feet at full extention is plenty long. I am thinking 3 DOF with 360 degree rotation at the base, one 90 degree pivot above the base and one 160 degree pivot halfway down the arm.

I know i will need at least 3 servos and have an idea of the torques that each will require. I have aquired the aid of a grad student for the programming, however am unsure of the materials to use structurally.

I would really appreciate some help with what I would need as far as:

A base for to allow for 360 degree rotation
Material for the joints and lengths of the arm
Adapters for the servos
Servo size recommendation
Extra Electronics (controllers, potentiometers)

It has to be able to lift and move an 8 oz glas of water (about 1/2 foot) at a moment arm of 2 ft.
Thanks again for your help.

Also, I have already deterenined the gripper assembly to hold the cup, just need the arm to get there.

Thank you again.

2

Hi landong,

Welcome to the RobotShop Forum. The arm you describe sounds very close to the RobotShop M100RAK:
robotshop.com/Images/xbig/en/robotshop-m100rak-robotic-arm-kit-no-electronics-B.jpg
[LEFT]You would need to design and build a custom gripper (which you asy you have already done). The arm should be powerful enough to lift a cup, just don’t overdesign the gripper. The base can rotate 252 degrees with position feedback or rotate continuously without position feedback.

The one consideration for the M100RAK is the open design - if it will be used around people without mechanical experience, we would strongly suggest enclosing the design to prevent pinch points.

You can operate it with almost any servo controller, but it is power hungry, so we suggest using the 5V output from a computer power supply. The SSC-32 is an all-around easy to use controller.

Hope this helps,
[/LEFT]