astro the rover - california state university, · pdf filerequirements of the university rover...

Astro the Rover Olympus Mons Rover Team 2014-2015

Purpose: • Design a robotic vehicle capable of performing tasks for a

sample return mission within the parameters and requirements of the University Rover Challenge.

University Rover Challenge: • International robotics competition for college students. • Held annually in the desert of southern Utah • Challenges engineering students to design and build the next

generation of Mars rovers that will one day work alongside astronauts exploring the Red Planet.

Literature Survey

Mars Science Laboratory Curiosity Rover

Mars Exploration Rover Opportunity Features:

6 Wheel Rocker Bogie Suspension 20 in Diameter Cleated Wheels Independent Wheel Steering Science Analysis Tools 5 DOF Arm Stowage System

Features: 6 Wheel Rocker Bogie Suspension 1.5 m x 2.3 m x 1.6 m Independent Wheel Steering Safely Operational at 30° (max) 5 DOF Arm Stowage System

Statement of Work

PHASE 1 PRELIMINARY DESIGN: Olympus Mons Rover Team shall generate a list of key components and modules for baseline approach. PHASE 2 DETAILED DESIGNS: Olympus Mons Rover Team shall finalize optical, mechanical, and electrical design. PHASE 3 MANUFACTURING: Olympus Mons Rover Team shall create any necessary manufacturing documentation and procedures. PHASE 4 TESTING AND INTEGRATION: Olympus Mons Rover team shall assist in creating a smooth, logical, and efficient work flow.

Project Schedule

Team Structure

Team Captain: Christopher

Nguyen

Chassis: Jerame Taylor

Weight Distribution

Accommodating Payload

Robotic Arm: Lauren

DuCharme

Yolanda Mora MelanieValenzuela

Arm Design

Grippers

Suspension: Ken Greene

Quy Tran

Rocker Bogey System

Rocker Arms

Wheels Assembly:

Greg Maisch

Chris Thompson

Protecting Gear Box and Motor

Connecting Wheels to Assembly

Telemetry/Visual Systems:

Maria Gutierrez

Optics and Moveable Visual

System

Camera Orientations

GPS

Matt Wolfenden Daniel Lu Nathan Johnson Carissa Pariseau1

A-Specs

Design Parameter Requirement Entire Vehicle Weight < 50 kg

Vehicle Volume < 1 m3

Vehicle Width < 32 in

Functional Temperature Range Up to 110°F

Minimum Lift Capacity 5 kg

Movement Control Wireless/Remote Control

Minimum Reach Capability 5 cm below ground

Science Tools pH and humidity meter

Video Feed Wireless

Frequency Band 900MHz-2.4GHz

ION Rover 2014

Features: 6 Individually controlled wheels Rocker bogie suspension 7.5 in diameter RC wheels 3 DOF Arm Closed loop feedback system

ION Rover 2015 Concepts

Chassis Design Concepts

• 2014: Used square wood base with aluminum channel siding • Electronics not protected

from environment • Limited space • Structurally unstable and

weak

Chassis Morph Chart

Function Possible Solution

Provide Support to

Vehicle C-Channel Bar-Stock Flat, Solid Tubing

Maintain Shape and

Strength Aluminum Steel Plastic PVC Carbon Fiber

Maneuverable Rectangular

Box Circular Octagon Square

Provide Space for Arm

and Electrical

Components

Flat Bi-Level -- --

Final Design Concept

• 2015: Aluminum frame with aluminum base plate

• Bi-level design • More easily

accommodates electronic components

• Second level could act as cover to protect components from dust or rocks

• Change in shape to prevent wheel or suspension interference

Suspension Design Concepts

• 2014: Rocker bogie suspension (2 rocker arms/2 bogies) • Middle wheel slippage • Low vertical travel

abilities • Bulky and under-

optimized

Suspension Morph Chart


Support Chassis Weight 8 wheels 6 wheels 4 wheels

Smooth Pivot Points Bearings Bushings None

Rocker Length within A-Specs 14” 15” 12”

Bogie Length within A-Specs 14” 13” 12”

Attachable to Assembly 4 Bolt Pattern Single Post Free Single Post Fixed

Support Load 0.25” Tall 0.375 Tall 0.50 Tall

Maintain Shape and Minimize

Deflection 0.125” Thick 0.25” Thick 0.375” Thick

Suspension Design Concepts

• 2014: Differential link • Heim joint had too

much play • Under-designed • Difficulties with

alignment and concentricity on rotational point

Suspension Morph Chart


Differential Type Differential Link Shaft (3 Bevel Gears) Shaft (4 Bevel Gears)

Shaft Diameter 1” 0.75” 0.5”

Bevel Gear Ratio 1:1 2:1 1.5:1

Shaft Material Carbon Fiber with

Aluminum Ends Full Aluminum Full Carbon Fiber

Mating Mechanism Keyways Set Screws Spring pins

Final Design Concepts

• 2015: Rocker Arm and Bogie

• Optimized for weight and strength

• Even weight distribution across wheels

• Clearance for 90° departure and approach


• 2015: Shaft with bevel gears

• 1:1 rotational ratio in rocker arm

• Improved concentricity difficulties

• More easily manufactured

Wheels Design Concepts

• 2014: Modified 1/5 scale RC wheels • Non-pneumatic tires • Required custom

components • Lacked motor adapters • Non consistent

compliance with substrate

• Bulky assembly • Sufficient traction

Wheels Morph Chart


Maintain Traction Rubber Cleats Pneumatic Foam and Tread

Meet Size Requirements 8 in 10 in 9.5 in

Motor Placement Protects

Power System

Gearbox Away from

Wheel

Gearbox Above

Wheel --

Should be Light Weight Rubber Aluminum Stainless Steel

Must be Easy to

Manufacture

Single Piece

Aluminum

Configuration

Pocketed Single

Piece Aluminum

Configuration

Separately Machined

Aluminum Plates


• 2015: Custom Wheel

• 10 in diameter • Not pneumatic

• More compact • Light weight • Elevated motor and

gearbox • Helps prevent

damage from rocks and dust

• Lower rotational inertia

Robotic Arm Design Concepts

• 2014: 3 DOF Planar Arm • Simple control system

forward kinematics • Limited range of

motion • Insufficient strength to

complete URC requirements

• Incapable of stowing

Presenter

Presentation Notes

The robotic arm used in last competition as a 3 DOF planar robotic arm constructed using off the shelf aluminum channels, brackets, servo hubs, etc. It utilized a linear actuator for the base joint and had limited reach capabilities. It was constructed with a small base lank that was connected to a significantly longer link that attached to a simple end effector. During competition, many of the tasks were incomplete and we received a zero. This was due to the limited load capacity the configuration could handle. The arm did not feature any type of stowing abilities, making it at risk of damage during competition.

Arm Morph Chart


Control and Power Systems Linear actuator Servo Stepper Motor Closed loop linkage

Must Attach to Gripper Interface Bracket Directly Mounted Removable Linkage Ball screw joint

Should Be Stowable Pre-Programmed

Upward Configuration

Pre-Programmed Downward

Configuration

Manual Upward Configuration

Manual Downward

Configuration

Length Must Have Sample Collection Reachability 25” 36” 20” 18”

Workspace Must Allow for Task Completion Below Above Adjacent to the

chassis All the above

End Effector Must Have Position Capabilities Linear actuator Servo Stepper Motor Ball screw

Must Be Mounted to Chassis Top Bottom Center Rear

Presenter

Presentation Notes

For this year’s arm, we considered many design solutions to meet the requirements of competition. We considered using stepper motors, servos, and linear actuators and decided to utilize a combination of a linear actuator for the base joint and servos for the elbow and wrist. In addition, we concluded that having a downward, pre-programmed configuration would allow us to stow and protect the arm during competition. We will also be mounting the arm to the center and top of the chassis.

End Effector Design Concepts

• 2014: 2 finger parallel gripper • Insufficient range of

motion • Lack of friction grip

abilities • Insufficient strength to

complete URC task requirements

• Single end effector not optimized for each task

Presenter

Presentation Notes

Last year’s model utilized an off the shelf, 2 finger parallel gripper. It was weak and incapable of handling the gripper requirements of competition. It also had a small jaw that made it difficult to grip objects of significant size. As you can see in the picture here, it was unable to turn the valves during the service task, which is something the competition rules have outlined as a necessity.

End Effector Morph Chart


Multi-Task

Functionality Removable Gripper

Fingers Removable Gripper Removable Final Linkage w/ Gripper

Sample Collection Capability Scooping Jaws Sample Coring Drill Sample Coring Probe

Sample Containment Capability

Glass Beaker on Top of Chassis

Canvas w/ Framing on Side of Chassis Bag Attached to Gripper

pH Analysis Capability pH Cards in Sample Receptacle

pH Probe in Sample Receptacle

Electronic pH Sensor w/ Arduino

Humidity Analysis Capability

pH Cards in Sample Receptacle

Humidity Probe in Sample Receptacle

Electronic Humidity Sensor w/ Arduino

Astronaut Assistance Capability

3 Finger Gripper with Independent Control

3 Finger Gripper with Overall Control 2 Finger Gripper

Servicing Task Capability

Re-use Astronaut Assistance Gripper

Conveyer Belt Finger Gripper 3 Finger Angled Gripper

Presenter

Presentation Notes

We considered many solutions for the end effector for each task. We considered utilizing a single gripper frame with removable pieces for each task, as well as a removable final linkage to minimize damage to the gripper during a disassembling. We are also considering the possibility of creating a sample analysis tool called a cone penetration tester that is used in geology to do sample analysis without removing soil samples from their original location.


• 2015: 3 DOF Planar Arm

• Larger workspace to accommodate multiple tasks

• Utilizes 4 bar linkage with linear actuator

• Configuration can be stowed to prevent damage during terrain traversing

Presenter

Presentation Notes

After multiple iterations, we have decided to pursue this design. It is also a 3DOF planar arm, but it has a larger workspace that last year’s model. It also uses a 4 bar linkage at the base connected to the linear actuator. We maintained the wrist rotation that was featured on last year’s model to allow us to complete competition tasks.


• 2015: Complete redesign

that features custom grippers for each task • Longworth chuck

• Equipment servicing task

• Knurled fingers for added grip

• Single finger actuation gripper • Astronaut assistance • Encompassing grip for

handles and object retrieval

• Sample collection scoop • Sample return task • Bulk sampling and

collection

Presenter

Presentation Notes

For the 2015 competition, we decided that doing a complete redesign with multiple grippers was the best option for us. We decided to create three different grippers, each of which is optimized for a specific task: scooping jaws for sample retrieval, a 2 finger gripper for astronaut assistance to pick up items with handles, as well as a three finger gripper for the servicing task. Each of these will attach using a bracket connected to the servo to allow for the wrist actuation of each mechanism.

Telemetry Design Concepts

• 2014: Telemetry

system • Individually

controlled wheel • Single Camera

Visual – via FPV • Unstable pan/tilt

servos • Lacked Visual

Clarity


• 2015: Arduino Mega: 54 I/O Pins, Input Voltage: 7-12V

• Arduino Uno: 16 I/O Pins, Input Voltage: 7-12 V

• HS-5685MH Servos (end effectors min. 3):

• Operating Voltage: 4.8-7.4V • Radio Frequency:

• Video feed: 5.8 GHz • Control: 2.4 GHz

• Antenna: (Cloverleaf & Air Max Bullet) • Power Rating: up to 24V

ION Rover 2014-2015

Features: 6 Wheel Rocker Bogie Suspension 10 in Diameter Cleated Wheels Independent Wheel Steering 3 DOF Arm with 3 Custom Grippers

Acknowledgements

• Jesse Grimes-York • Brett Kennedy • Jet Propulsion Laboratory • Dr. Nina Robson • Dr. JiDong Huang • Ye Daniel Lu – CSUF Electrical Engineering Student • CSUF Geology Department • CSUF Electrical Engineering Department • CSUF ION Website Design Team

astro the rover - california state university, · pdf filerequirements of the university rover...

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