Week of Apr 16 – System Validation (SVD) & Final Integration
4.16.26 Mechanical Status Update
The project has reached its primary objective: the Spring Validation Demonstration (SVD). Over the last two weeks, we transitioned from indoor bench testing to full outdoor autonomous operations. Every custom-fabricated component—from the 3D-printed vertical mounts to the machined aluminum couplers—is now fully integrated and performing under field conditions.
Key Outcomes:
- Field-Ready Integration: The full planting mechanism is securely mounted and functional. All 3D-printed parts have been stress-tested for vibration and soil resistance during outdoor travel.
- FSM Execution: The Finite State Machine (FSM) successfully governs the entire cycle. The robot now autonomously transitions from navigation to site identification, executes the auger plunge, and triggers the seedling drop without manual intervention.
- Unified Operation: The “Pick-and-Place” sequence is fully synchronized. The xArm correctly interacts with the chute assembly, ensuring seedlings are delivered to the drilled hole with high repeatability.
- Outdoor Validation: Successfully completed multiple planting cycles in varying soil densities, confirming that the NEMA 23/Ball Screw and Linak LA36 combination provides sufficient force for reforestation tasks.
Updated Issue & Mitigation Log
With the completion of SVD, the major technical blockers have been resolved through hardware workarounds and final software tuning.
| Issue | Description | Mitigation / Resolution | Status |
| PCB Burnout | Custom PDS PCB shorted during final assembly. | Alternative Power: Implemented a robust manual power distribution rail using off-the-shelf components. | 🟢 Resolved |
| Assembly Complexity | Tight tolerances made the initial build-out slow. | Final Fitting: Hand-processed and filed 3D prints for a flush fit; system is now fully rigid. | 🟢 Resolved |
| Arm Safety (E-Stop) | xArm and Warthog e-stops were independent. | Integrated Safety: Successfully unified the hardware safety loop into a single emergency circuit. | 🟢 Resolved |
| Compute Constraints | Jetson Nano processing limits. | Task Scheduling: Optimized the ROS2 node execution to ensure high-priority navigation takes precedence. | 🟢 Resolved |
| Schenley Park Testing | Risks associated with unknown terrain and soil. | Field Hardening: Verified mechanical stability on inclines and validated auger torque in damp soil. | 🟢 Resolved |
Final Reflection
The reforestation robot now stands as a complete, end-to-end autonomous platform. From the initial CAD sketches in January to the machined parts of March and the final integrated system of April, the mechanical subsystem has evolved into a reliable, field-tested unit. The project concludes with a successful demonstration of autonomous soil penetration and seedling delivery.
Week of Apr 3 – Assembly Realities & System Integration
4.03.26 Mechanical Status Update
The last two weeks have been a masterclass in “Design for Assembly” (DFA)—or rather, the challenges that arise when parts don’t align as perfectly in the shop as they do in SolidWorks. The focus shifted from fabrication to the high-stakes task of mounting the full planting mechanism to the Warthog base.
Key Outcomes:
- Horizontal & Vertical Actuation: Successfully mounted the plywood mounting board to the horizontal robot mount. We verified that the ball screw motor assembly provides smooth horizontal travel for the vertical subsystem.
- Component Marriage: Integrated 3D-printed custom mounts with the Linak LA36 linear actuators, the auger assembly, and the chute.
- CAD Finalization: The master assembly model is now complete (pending final sensor and xArm placement), providing a digital twin for the physical build.
- FSM Testing: Collaborated with Alina to test the Finite State Machine (FSM) for the planting cycle. Initial tests with the auger and chute hardware indicate the logic is sound.
Current Challenges:
- Assembly Tolerances: We discovered that small deviations in part placement make joining components significantly more time-consuming than anticipated. It’s a lesson in leaving more “slop” or adjustment room in future designs.
- Electronics Setback: A critical failure occurred when the Power Distribution PCB shorted and burned out during testing. We are currently pivoting to alternative power distribution methods to stay on track for SVD.
Week of Mar 20 – Machining, Clearance, and Project Pivots
3.20.26 Mechanical Status Update
Returning from Spring Break, the priority was identifying physical constraints that weren’t obvious in the initial sketches. Most notably, we discovered that the robot mount needed to sit significantly higher on the Warthog to provide enough clearance for the robot to navigate inclines without bottoming out the planting mechanism.
Key Outcomes:
- Shop Progress: Used milling machine to fabricate custom connectors. These parts allow the Linak LA36 actuators to interface securely with the 80/20 aluminum extrusions.
- Revised Mount Design: Updated the robot mount CAD to a “high-clearance” configuration, utilizing T-slot rails and ball bearing blocks for the horizontal axis.
- Management & Budget: Established a formalized Internal Bill of Materials (BoM) and budgeting system. We’ve moved into more structured Agile sprints to tighten the feedback loop between the mechanical and software teams.
Current Challenges:
- Control Logic: While individual actuators (Stepper, Linear, BLDC) have been tested, the unified control logic is still in the “individual script” phase and needs to be consolidated into a single ROS2 node.
Week of Feb 19 – Stepper Validation & Integration Sprints
2.19.26 Mechanical Status Update
The project has moved into the “Unit Testing” phase for electronic-mechanical interfaces. The primary accomplishment this week was the successful validation of the NEMA 23 stepper motor. Testing confirmed that the torque profiles are sufficient for the intended vertical travel of the planting mechanism.
We are now moving into a “Mechanical Sprint” to integrate these validated motors with the ball screw system to create a functional linear slide.
Key Outcomes:
- Motor Validation: Confirmed stepper motor functionality and control parameters.
Next Steps:
- Full Integration: Couple the validated stepper motor with the ball screw assembly.
- Actuator Configuration: Set up and calibrate the linear actuator travel limits.
Week of Feb 19 – Stepper Validation & Integration Sprints
2.19.26 Mechanical Status Update
The project has moved into the “Unit Testing” phase for electronic-mechanical interfaces. The primary accomplishment this week was the successful validation of the NEMA 23 stepper motor. Testing confirmed that the torque profiles are sufficient for the intended vertical travel of the planting mechanism.
We are now moving into a “Mechanical Sprint” to integrate these validated motors with the ball screw system to create a functional linear slide.
Key Outcomes:
- Motor Validation: Confirmed stepper motor functionality and control parameters.
Next Steps:
- Full Integration: Couple the validated stepper motor with the ball screw assembly.
- Actuator Configuration: Set up and calibrate the linear actuator travel limits.
Week of Feb 12 – Auger Assembly & Hardware Layout
2.12.26 Mechanical Status Update
This week saw progress in CAD assembly and the design for the new planting mechanism. We drew a sketch of the initial idea for the full planting system. Parts were acquired for the ball screw system, and the purchase of the second linear actuator is imminent.
We completed the initial auger assembly and placed orders for the specialized coupling components required to interface the auger with the linear actuators and motors.
A major focus was the “high-level layout” of the robot. We began brainstorming the spatial arrangement of sensors, power supplies, and cable routing to ensure the mechanical footprint of the planting mechanism doesn’t interfere with the robot’s navigation sensors.
Key Outcomes:
- Subsystem Assembly: Completed the physical build of the auger unit.
- System Architecture: Initiated the “Master Layout” for hardware integration (Sensors, Mounts, PCBs).
- Integration Planning: Defined the interface between the ball screw motor and the modified auger/chute assembly.
Current Blockers:
- Arrival of specialized connectors for the stepper motors and linear actuators.
- Shortage of 80/20 extrusions and fasteners for rapid prototyping of the frame.
Week of Feb 5 – Component Design & Prototyping Prep
2.5.26 Mechanical Status Update
The focus shifted toward detailed sub-component design. Effort was directed into translating conceptual sketches of the planting mechanism into functional CAD models. Specifically, we began modeling a linear actuator and auger assembly, which will serve as the core of the soil-penetration system.
We also finalized the mechanical budget sheet to ensure all long-lead items (motors, fasteners, and actuators) are ordered to prevent future assembly delays.
Key Outcomes:
- CAD Development: Progressed on the linear actuator and auger sub-assemblies for the CAD assignment.
- Procurement: Finalized the Bill of Materials (BOM) and budget for the mechanical subsystem.
- Visual Validation: Developed rough sketches of the planting mechanism to facilitate design reviews.
Current Blockers:
- Pending motor control code remains a hurdle for testing legacy hardware.
Week of Jan 29 – Hardware Foundation & Initial CAD
1.29.26 Mechanical Status Update
This week marked the transition from high-level planning to physical integration. The primary focus was establishing the robot’s physical footprint and kickstarting the design phase for the custom planting hardware. We successfully mounted the xArm to the mobile platform, providing a stable base for future manipulation tasks.
Parallel to the physical mounting, we initiated the CAD workflow for the new planting mechanism. Early efforts are focused on evaluating the “old” planting mechanism to identify failure points and areas for optimization.
Key Outcomes:
- Physical Integration: xArm successfully secured to the Warthog base.
- Design Phase: Initialized CAD models for the planting mechanism and defined requirements for the end-effector.
- Benchmarking: Established a baseline by retrieving the legacy planting hardware for testing.
Current Blockers:
- Sourcing the Anker battery to power the planting subsystem.
- Acquiring legacy motor control code for the Steward motors to begin comparative testing.
