Workflow
Shopping Robot
Design, Manufacture and Assemblage Background In order to assist people with disabilities and the aged people to buy goods in supermarkets, the concept of remote controlled shopping robot have been proposed. Such a robot is designed to provide those groups of people with an easy and comfortable shopping experience as common people enjoy. The remote controlled robot is required to implement the function that moving to the shelf at first and then clamping the goods, which are represented by small cubes and balls here.
5 5
1
Move toward the shelf
1 2
Adjust the manipulator and grab goods
2 3
Move toward storage area with goods
3 4 4 6 6
Drop down goods Repeat step 3 and 4 until all needed goods are obtained
Done
Function Analysis Moving Forward Linear Motion Moving Backward
March
Base
The Base Subsystem
Horizontal Positioning
Arm
The Arm Subsystem
Vertical Positioning
Waist
The Lifting Subsystem
Cripping
Hand
The Gripping Subsystem
Turing Left
Steering
Grab
Driving Wheels
Guide Wheels
Turning Right
Function
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Mechanics Diagram
Structure
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Subsystem
The Arm Subsystem The Gripping Subsystem
Gear
Nut and Screw
Coupling Worm Motor
The Lifting Subsystem Wheel
Worm Gear
The Base Subsystem
Subsystem Design ---- The Arm Subsystem *
The main function of the arm subsystem is to adjust horizontal position and ensure the gripping subsystem move flexibly in the shelf area.
The horizontal position is achieved by the cooperation of the base and the arm. Since the property of base limit its function into coarse positioning, the arm need to achieve precise positioning.
1) Together with the base subsystem, stretch the gripping subsystem to the good to be picked up; 2) After obtaining the good, pull back the gripping subsystem on the top of the basket and drop off the good.
1
* Subsystem Design is divided into four tasks and each group member was responsible for one of them. I was in charge with the arm subsystem.
Mechanics analysis and calculation have been done with critical components, such as shafts and screws, in order to ensure the whole system can work in stability and security, without appearance of situation such as shaft facture or gear stuck. Based on these results, the final sizes and specifications of structure have been determined.
Single-axis rotation is able to sweep a sector area, but its positioning is not precise enough, and the motion path is too simple as well. Therefore, the two-degree-of-freedom link mechanism is chosen, in terms of its precise positioning and high ability of regulation.
Function Analysis
2
Principle Scheme
3 Mechanics Analysis
Schematic Graph of Principle 1 2 3 4 5 A B C
Rear Arm Fore Arm Gears Couplings Motor Joint with Hand Fore-Arm Axis Rear-Arm Axis
Schematic Graph of Coverage
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• • ---
Rear-Arm Axis Fore-Arm Axis Hand
Subsystem Design ---- The Arm Subsystem
In terms of lack of practical experience, the first edition of drawings contain problems calling for more consideration. Take the revision of the bracket part as an example. The initial design of one-piece bracket had several disadvantages requiring high precision during the process of manufacture. Moreover, the bracket as the whole part was large in both size and mass, thus obtained a poor stiffness and it was easy to deform; According to these reasons, the bracket then was split into four individual parts. Through making this improvement, the fabrication difficulty and weakness were reduced and the subsystem was easier to assemble.
4 Assembly Drawing and Parts Drawings
5
Manufacture and Revisions
Product