Build & Test Prep
Table of Contents
Team Vision for Build & Test Prep PhaseThe team convened two weeks prior to the beginning of Spring semester to put in valuable work in order that TigerBot VII may be completed on time considering the vast scale of the project. In addition to finalization of Mechanical designs, the Electrical team converged on ready-to-order rev 1 PCB designs. The primary system-level progress points made during Intersession are listed below and will be further detailed.
- Spine-Mounted Power Supplies
- Spine-Mounted Electrical Enclosure
- Emergency Mechanical Stops Integration
- Designed for Manufacturability
- Electrical Component Models
- PCB Footprint Optimization
- Spinal-Column Cooling System
- Shoulder Flexion Drives
- Conceptual Counterweight Arms, Stand-in head sensor package
Mechanical Team R&D ProgressThe Mechanical team has a number of research and development mini-projects running in parallel with the primary system-level project work. These specialty-focus components require additional materials testing, sourcing, or preliminary research for concept validation before making it into the final design. Shown below are the Mechanical team's R&D focus projects from the intersession.
Manufacturing ProgressThe largest remaining barrier to the completion of TigerBot VII is the large volume of parts that must be manufactured. Many components have been redesigned to facilitate more rapid manufacturing, enabling greater throughput without sacrificing critical performance goals. In addition, the team has fully verified the material bounding boxes to all of the machined parts, allowing for more raw material to be confirmed and ordered. The incoming orders of metal along with the staged release of drawing packages lets the team leverage university machining staff to parallelize manufacturing.
Electrical Team Progress
Software Testing/PlanningTest plans were made and implemented to test ROS communication between the ODroid and the Teensys:
The Communication Stability test led to the design of a Heartbeat function to keep track of the statuses of the Teensys:
Clarification of Software User Interface Requirements:
- ROS Package/Teensy Library
- Documentation and instructions
- Simple GUI/launcher for scripts and single line commands (like for adjusting motor angles live)
- Velocity and position control
- Turn key demo
- Ability to both build upon and modify base code
- Test Teensy to encoder communication after connector is wired up
- Test motor and encoder control once above is done and test-fixture is made
- Test Variense IMU reading once it comes in and work on ROS interface for it
- Make previously-implemented Teensy code more modular and populate Teensy library with it
Board Stack ConceptThe overall board concept requires a high level of functionality, a small footprint and modularity for future development. This lead to the stack up design seen below.
Teensy Breakout BoardThe top board of the stack is the Teensy Breakout, which networks the micro controller to the necessary I/Os. A 12V to 5V switching regulator was incorporated into the design in order to handle the large power drop from the 12V to 5V line. Future revisions are in the works to reduce the footprint size and stack height.
Motor Interfacing Board
The motor interfacing board handles the logical interfacing between the Teensy, the Clearpath Servos and CUI/Zettlex encoders.
Current Sensing Board
Current sensing was determined to be a necessity for implementation of torque controlled algorithms. The current draw from the Clearpath Servos is measured through a shunt resistor/amplifier configuration that outputs an analog voltage level to be fed up the stack to the Teensy for correlation.
Test PlanThe Hardware DVT document outlines the procedure for testing and verifying PCBs.
Design Review MaterialsFor the EE Design Review held early this semester:
Plans for next phase
- As a team, where do you want to be in three weeks at your next review?
- As an individual on the team, what are you doing to help your team achieve these goals? (Use the individual 3-week plan template for this)