Robotic Arm & Dexterous HandSenior Design
Preliminary Design Report
Project 05911
David Parrett
Wen Jia Wang
Justin Tubiolo
Jeremy Amidon
Ken Peters
Executive Summary
The purpose of this report is to describe the design process of an interactive robotic arm and hand to be placed in a museum environment for the enjoyment of children. It was the intention of the Rochester Museum and Science Center (RMSC) for the team to propose various exhibit ideas that utilize robotics and then to develop one of these ideas into a working exhibit for actual display and use in the museum. With a large emphasis on the word "fun," the team set about to find a creative and inspiring idea that would not only appeal to children but also serve to enhance their creativity and learning. The end result was the concept of a robotic arm and dexterous hand which the children can control through use of a wearable glove that tracks the movements of their hand, arm, and fingers. The robotic arm and dexterous hand are used inside of an enclosed area to move, lift, and otherwise interact with various objects inside of the display area. The main goal for the team has been to allow children to successfully transfer their movements to the movements of the robotic arm and hand while keeping it fun and exciting for the children.
By using the Engineering Design PlannerTM methodology, the team was able to design the Robotic Arm and Dexterous Hand through five different facets.
The first facet of the design is called Recognizing the Need and Defining the Problem. The team has spent a large part of this past design period conferring with the RMSC to establish the needs for this project. Issues such as safety, repair, interaction, and learning have all been discussed along with the usual issues of normal operation. In order to choose the project, a list of project proposals was created and submitted to the sponsor. Once the project was decided and key issues and objectives had been defined, it was important that the team propose many different concepts for the museum to choose from and then to further develop the final project idea into a list of necessary components and activities. This Concept Development is included as the second facet of this report. The third facet, Feasibility Assessment, is concerned with analyzing the different design alternatives to meet a specific need in the design. Choices such as whether to design and manufacture a specific component or to buy one pre-manufactured are considered while weighing the costs and benefits of each decision. The resulting design choices then allowed the team to generate the fourth facet, Specifications for how exactly the robotics will mechanically and electrically work. Using these decisions and specifications, the team then took the final step in the design process, Analyses and Synthesis, to finalize and fill in the design details including technical drawings and algorithms.
Though the team foresees that modificationswill need to be made to the final design, the major conceptual part of the project has been finalized. The robotic arm shall be mounted to an overhead support. The robotic arm shall include 180 degrees of rotational movement at the mount location, it shall extend and retract a distance of at leastone foot, it shall include a joint at the elbow and wrist, and it shall allow for the bending of all five fingers of the hand along one axis. The control of the robotic arm and hand shall be accomplished through the use of a wearable glove which is attached to the hand of the user.The glove shallbe able to detect the motion of each finger and the motion of the user's handinside the glove relative to a fixed infrared sensor.
The team is now engaged in securing the necessary materials and components of the design and building the robotic arm. Once completed and operational, the design will be testedto ensure that it meets not only the operational specifications but also the desired human interaction when placed in a museum exhibit environment.
Executive Summary
1.0RECOGNIZE AND QUANTIFY NEEDS
1.1Mission Statement
1.2Project Description
1.3Scope Limitations
1.4Stakeholders
1.5Key Business Goals
1.6Top Level Critical Financial Parameters
1.7Financial Analysis
1.8Market
1.9Order Qualifiers
1.10Order Winners
2.0PROJECT PROPOSALS
2.1Robotic Arm and Dexterous Hand
2.2Robotic Squirt Gun and Targets
2.3Remote Racing and Track
2.4Robotic Arm Wrestling
2.5Remote Soccer Players
2.6Robotic Basketball Shooter
2.7Interactive Maneuverable 3-D Maze
2.8Conclusion
3.0Concept Development
3.1 Controls
3.1.1Sensor Laced Glove & Fighter Style Joystick
3.1.2Sensor Glove with Motion Track
3.2Arm Types
3.2.1Wrist, Elbow, & Shoulder Joints
3.2.2Wrist, Elbow & Rotating Cylinder Joints
3.3Source of Mechanical Power
3.3.1Pneumatics
3.3.2Electric Motors
3.3.3Hybrid System
3.4Electronic Data and Control System
3.4.1PC with an output board
3.4.2Microcontroller Development Board Alone
3.4.3PC with a Microcontroller Development Board
4.0Feasibility
4.1 Project Feasibility
4.2Controller Feasibility
4.3Arm Feasibility
4.4Electronic Control Feasibility
5.0 OBJECTIVES & SPECIFICATIONS
5.2Design Objectives
5.2Performance Specifications
5.3Design Practices
5.4Safety Issues
6.0DESIGN ANALYSIS & SYNTHESIS
6.1Display Analysis & Synthesis
6.2Hand Design Analysis and Synthesis
6.3 Forearm Design Analysis and Synthesis
6.4 Upper Arm Design Analysis and Synthesis
6.5 Equations Used for Mechanical Design Analysis and Synthesis
6.6 Electrical Control
6.6.1 Electrical Input and Output Specification
6.6.2Electrical Control Algorithm
7.0 PROJECT TIMELINE
8.0PROJECT BUDGET
1.0RECOGNIZE AND QUANTIFY NEEDS
1.1Mission Statement
The purpose of this senior design team is to create a robotics display for the RMSC which is fun, inviting, accessible, and easy to understand and use. The new display will be a robotic arm and dexterous hand which will copy the movements of the user's hand in a glove controller. The robotics display will be suitable for placement and use on the museum floor as a working exhibit to be used especially by children ages 8-14.
1.2Project Description
Robotics is a field of technology in which there is a great demand and natural curiosity to explore what intelligent machines can do to help people. A robot can be either very intelligent and responsive to its natural environment, or it can perform a set task without any intelligent response. In this project it is important for the safe and normal operation of the robot, that it respond to its environment by detecting when it has reached its fullest extent of motion or has collided with an immovable object to cease movement in that direction. It is also important for the robot to maintain a smooth, steady motion which corresponds to how the user desires the robot to move.
Besides simply moving around and mimicking the motion of the human hand and arm, the robot will also be capable of performing three or four tasks which will present a small challenge and add interest to the display. It was mentioned by the RMSC that the arm should perform activities that could not easily be done by the children with their own hands. One possible example of this is to allow the robot to pick up a basketball with one hand and place it in a basket. Another possibility is to have the robot pick up a recognizably heavy object such as a construction brick and be able to stack several of them together. Other possible activities could be placing odd-shaped objects through corresponding holes, and touching the robotic hand to a target where the hand will conduct electricity to turn on a light.
The basic shape and layout of the exhibit is demonstrated in Figure 1-1. The arm is shown supported from above the display table where the various objects for interaction will be located. The arm features rotational movement at the mounting point to allow it to swivel from side to side. Just below this rotational motor is located a cylinder which allows the arm to extend and retract give the arm variable reach. Below the extension cylinder is the elbow joint for the arm allowing it to bend in various life-like postures. On the forearm section below the elbow joint will be placed air muscles which will allow the wrist and individual fingers of the hand to bend.
The control area is located in front of the display case and houses the glove controller. In order to save wear and tear on the controller and allow the glove to operate properly with the sensor, it is necessary to surround the glove on all but one side to limit the user's freedom of movement. The limitation allows the user enough freedom to move the glove in all directions for between one to two feet from center and keeps the glove on a restraining leash to make sure it remains with the exhibit.
1.3Scope Limitations
One major idea which the team is striving for is to avoid reinventing and remanufacturing pre-existing design components. It is necessary for the team to purchase working components in nearly all cases to keep the cost low and provide the working prototype by the established deadline. Though it would be possible to completely design and manufacture the project from scratch, especially the glove controller, this would require much more design, manufacture, and test time than is available for this project.
The team is limited, to a degree, by the $5000 budget but the team does not believe that the project will need to cost more than this. Responsible spending and good component choices are important to staying within this budget constraint. The RMSC has been very supportive in promising facilities such as a compressed air line for pneumatics components and has showed a desire to avoid placing creative limits on the project in general wherever possible.
The major constraint of the project is the schedule which is set to a strict timeline with two main deadlines. At the end of the fall quarter, 20041, the team must deliver the detailed design package, quotes for vendors, and the proposed budget. By the end of the winter quarter, 20042, the team will provide the working prototype, the final report, and test results of both the operational specifications and human interactive requirements.
1.4Stakeholders
The main stakeholders in this project are the project sponsor, RochesterMuseum and ScienceCenter, and the senior design team members. The Museum has a large stake because of the possibly huge attraction and technologically-advanced image that this project could bring to the RMSC should it be integrated successfully as an exhibit there. The senior design team members also have stake in this project as a demonstration of their ability to solve engineering problems and gain invaluable experience in the expanding field of Robotics.The team's faculty advisorsand the college of engineering also has stake in the project because of the potential for future sponsorship of senior design projects by the RMSC. Outside vendors are also stakeholders which the team shall be purchasing many of the commonly manufactured parts for integration in the design. More stakeholders include the members of future RIT robotics senior design teams, other schools doing research on miniature turbines that could benefit from our results, any other designers and users of publicly exhibited robotics, and the future employers of the team members.
1.5Key Business Goals
A successful project will be defined by the evidence of a working robotic arm and dexterous hand prototype achieving full dexterity, range of motion, and control by the user to manipulate the objects inside the display. If the design team is capable of completing such a task, then much will have been accomplished. Not only will the core objectives of the project be achieved, the students on the team will have also gained a valuable experience in working within a multidisciplinary team. The results of this project will serve as a tangible incentive for further development by museums in robotics displays. Success of this project will bring future opportunities for attracting a wide group of interested young people into the museum, and possibly eventually into the study of engineering and the field of robotics.
1.6Top Level Critical Financial Parameters
The financial needs of this project are driven primarily by the purchase of the individual components that will be assembled for the mechanical robotic function. The major electrical system contributors to the overall cost include a personal computer and microcontroller development board. The major mechanical cost contributors include the pneumatic system, including air muscles, air lines, and valves, alongwith the mechanical joints, motors, and extension cylinder. There may also be small fees due to persons external to the team, who are responsible to manufacture various mechanical components but these will be relatively small in comparison to off-the-shelf mechanical purchases.
1.7Financial Analysis
The team is working with a $5000 dollar budget cap in mind. The RMSC will work with the team to determine which possible budget items can be donated and which will need to be purchased. The plan for spending is to purchase the major components of the design that are absolutely necessary by the Preliminary Design Review and at an early stage of assembly in the following quarter to ensure that they will be properly integrated and to allow for a fallback period if necessary. The $5000 dollar limit is deemed by the team to be sufficient for this project; however there are several design options which, if chosen, would add to the cost significantly. The electrical components will require an estimated five hundred to seven hundred dollars and the majority of funds will go to the mechanical side of the project including, but not limited to:
- Pneumatic component cost: air muscles, valves, and lines
- Mechanical control components: extension cylinder and electric motors
- Material and machining cost: hand and finger joints
1.8Market
The Robotic Arm and Dexterous Hand Display is intended to be used exclusively by the RMSC. Though the design and concepts used throughout this project will be available to the RIT community and could prove useful to similar projects in the future, it is not intended that this project be reproduced for public marketing and distribution.
1.9Order Qualifiers
The purpose of this research design is to provide a fun and interactive display for use in a museum exhibit by children. The robot needs to satisfy this requirement by allowing the user to control it simply and easily which will translate to an efficient and pleasing operation of the robotic mechanism. The operation must involve the ability to move fingers, hand, and arm throughout the display unhindered, and it must allow the user to interact with the objects inside the display in an intuitive manner.
1.10Order Winners
If time and money permit the team will work to complete the following goals:
- Design and build to ensure maximum exhibit life span and durability.
- Provide for intuitive navigation and operation by users.
- Allow the robotics theme to be an exceptionally inviting "attractor factor."
- Provide for accessibility to many users of different age and physical ability.
- Provide maintenance information such as drawings and replacement parts.
- Make the user feel as though the robotics exhibit is an extension of them self.
- Test the display in its target museum environment to ensure its success.
2.0PROJECT PROPOSALS
The RMSC requested that the team brainstorm and propose various robotics display ideas to be considered for this project. The ideas were in many different directions but always centered on being interactive and inviting to children. The following are the seven project ideas which were proposed.
2.1Robotic Arm and Dexterous Hand
2.1.1Overview
This design concept incorporates a robotic arm with a fully functional robotic hand. The arm and hand could be used to complete various tasks like stacking blocks or lifting and moving heavy objects. The robot would be contained in a display case that would be easily viewed by the operator as well as spectators.
2.1.2The "Attractor Factor"
The sight of the robotic arm and hand should be a significant draw. Also, the controls will draw people to try the glove and joysticks.
2.1.3Method of Interaction
The arm and hand would be controlled by sensor-laced glove and one to two joysticks. Patrons would put the glove on and the robotic hand would mimic the movements of their hand. The joysticks would be used to control the motion of the robotic arm. We would explore the possibilities of incorporating different size gloves like a small, medium, and large to increase the range of ages allowed to operate the robot.
2.1.4Scientific Learning
We would like to look into the possibility of smaller display cases around the outside of the robot case that would contain various parts and equipment used in the robot with explanations as to what they are for. These display cases would allow people observing the robot to see what types of technologies went into making the robot and hopefully learn a little about robotics.
2.1.5Intuitive Operation
This display would not require elaborate instructions before using because you would learn to operate it by playing with it.
2.1.6Materials
The mechanics of the robot would most likely be comprised of steel and aluminum components to ensure durability. There would be a multitude of electronic sensors, circuitry and motors to control the robot. We are looking into the different methods of creating the motion of the robot including electric, hydraulic and pneumatic.
2.2Robotic Squirt Gun and Targets
2.2.1Overview
The squirting hand is an idea which incorporates a robotic hand with a squirt gun. The squirting part would be built into one of the fingers. In the display would be several targets and other things that kids could shoot water at. One idea was to put a turbine which they can shoot at and light a light bulb. They could then experiment with shooting the turbine in different places and seeing which spins it faster, lighting the bulb brighter. This idea is also a possibility to combine with the sensor/glove idea. Basically, I envision a display case with the hand on one side. The controls will be behind the hand and in front will be a “shooting range” with whatever targets we would choose.