April 29, 2025
Objects and Landmarks to Detect:
Human Presence: The robot must detect a human seated in a designated chair within the exercise area. Detection will occur using Stretch's built-in depth and wide-angle cameras.
Exercise Zone Boundaries: The robot must be aware of predefined areas in the environment where it can move safely without colliding with walls or other robots.
Level of Precision and Temporal Continuity:
Moderate Precision: Since the robot is mainly sliding left-right (parallel to the user), it does not need exact precision but must maintain alignment with the user's arm position within a few inches.
Continuous Tracking: The system must continuously recognize if the user remains seated and engaged during the session, ensuring the robot maintains appropriate proximity throughout the exercise.
Objects to Interact With:
Human Hand: The Stretch robot's gripper will be equipped with a flat 3D printed push sensor attachment with variable resistance. This sensor will detect the user's applied force during the exercise.
Exercise Target Surface: The flat surface will act as a dynamic goal for the user to push against, allowing for gradual strength and range-of-motion training.
Manipulation Strategy:
The gripper will stay in gentle contact with the user's hand throughout the exercise, providing continuous resistance for training shoulder and arm muscles while tracking exerted force.
Required Navigation Capabilities:
Linear Movement: The robot base must move precisely along a straight path — sliding left and right relative to the user. There is no need for complex pathfinding or mapping. Predefined safe zones will guide movement, preventing deviation or collisions.
Positioning Relative to Landmarks: The robot must align itself consistently with the user's seated position and maintain that alignment while moving.
Required User State Information:
Exercise Engagement: The robot must know when a session has started and monitor continuous pressure against the sensor to ensure active participation.
User Inputs:
Start and Stop Commands: Users will be able to start or stop the exercise via a simple interface (web interface or touchscreen).
Progress and Results Access: Users can log in with a username to view historical performance metrics, showing improvements in strength and motion over time.
Robot Feedback to User:
Real-Time Feedback: The robot will provide visual feedback if force thresholds are met or if the user needs to adjust position.
Session Summaries: After each session, the robot will display metrics like peak force applied, average pressure, and range of motion improvements.
Human Monitoring Requirements:
Minimal Oversight: Ideally, a single doctor or therapist oversees multiple robots (6+ robots operating simultaneously in a therapy room).
Emergency Intervention: A centralized control station will allow the doctor to immediately stop any robot if an issue arises.
Environmental Modifications Needed:
Defined Movement Tracks: Mark or slightly modify the floor with guide lines or shallow tracks to ensure robots move precisely along their designated paths.
Designated Seating Areas: Fixed chairs should be placed in known locations to standardize robot positioning relative to each user.
Push Sensor Integration: Attach a flat, cushioned force-sensing surface to the robot gripper to enable safe and effective physical interaction.
Open Floor Plan: Remove obstacles that could disrupt robot motion and ensure adequate spacing between users to avoid collisions.
Charging Stations: Provide docking areas at the perimeter of the room for robots to recharge when not in active use.
By focusing our Stretch robot’s design around simple, repeatable movements with rich sensory feedback and minimal need for human intervention, we aim to create a scalable solution for physical rehabilitation. Our technical and environmental choices are all intended to support effective therapy, user safety, and group efficiency, helping patients regain independence faster and with lower costs.