Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 8 | Hybrid Actuation Arm Exoskeleton |
Alan Lu David Song Rubin Du |
Haocheng Bill Yang | design_document1.pdf proposal1.pdf |
|
| **Team** Alan Lu -- jialin8 Rubin Du -- rd25 **Problem** Lifting and carrying heavy objects is a common but physically demanding task faced in both personal and industrial environments. Whether it is a person at home carrying groceries or a logistics worker handling cargo, repetitive lifting puts stress on the musculoskeletal system and can result in fatigue, reduced productivity, and even long-term injuries. Existing exoskeleton solutions often focus on industrial use, but they suffer from limited backdrivability, high weight, or overly complex designs that prevent practical everyday use. A lightweight, safe, and efficient solution is needed to reduce the physical burden of lifting while maintaining user freedom of movement. **Solution** Our team proposes the development of a wearable exoskeleton system designed to assist users in lifting objects of up to 10 kilograms with minimal effort. The system employs a hybrid actuation strategy that combines the strengths of both a BLDC motor and a servo motor: the BLDC provides the torque required for large-angle lifting motions, while the servo supplies stable holding torque to maintain the lifted position without excess energy drain. The BLDC goes through a 64:1 planetary gear set to amplify torque, and the servo motor goes through a moveable linkage system to create sufficient mechanical advantage to further reduce the load on the motor. A detachable drivetrain allows the user to disengage the actuation system, enabling free arm movement when lifting support is not required. The skeleton itself is lightweight, manufactured using carbon-fiber-reinforced nylon (PA-CF), ensuring durability and comfort. This modular design starts with elbow actuation and can be scaled to include shoulder actuation, broadening its application. **Solution Components** **Subsystem 1: Mechanical Skeleton and Drivetrain** - Lightweight PA-CF composite structure, under 3 kg excluding the battery. - Hybrid drivetrain using BLDC with planetary gear for motion and servo motor for holding. - Drivetrain disengagement mechanism for free arm movement. - Moveable armor integrated with a linkage system on the drivetrain that elaborately moves upper limb armor to avoid structural interference. **Subsystem 2: Actuation and Power System** - Actuated by BLDC + servo combination for efficiency and safety. - Powered by a 6S LiPo battery (~200 Wh), providing several hours of continuous assistance. - Custom PCB with DC-DC buck converters for peripheral loads and power distribution. - Thermal management through ventilation and optional forced convection. **Subsystem 3: Control and Signal Processing** - Joint actuation regulated through PID controllers. - User intent detected via EMG sensors integrated into the arm. - Signal conditioning pipeline: Kalman filter → Chebyshev low-pass filter → controller input. - Optional manual override via a simple forearm-mounted control panel. - Microcontroller and peripheral signals integrated on a customized PCB/FPGA. **Subsystem 4: Peripherals** - Armor ambient light will be integrated into the shell of the skeleton for aesthetics. - Ventilation port openings will be controlled by microservos to ensure good heat dissipation. - A manual control panel will be placed on the lower limb skeleton to include manual operations and emergency switches. - TPU-based soft pads inside the skeleton to provide a comfort experience for the user. **Scalability and Modularity** - The initial prototype targets elbow actuation. - Design is scalable to include shoulder actuation grounded to chest armor. - The modular approach ensures meaningful demonstration even if full-body integration is not achieved. **Criterion for Success** The final solution will be a wearable exoskeleton capable of assisting the user in lifting and holding objects up to 10 kg through a dual-actuation BLDC–servo system with a detachable drivetrain for free arm movement, powered by an onboard 6S battery, lightweight (under 3 kg excluding the battery), and controlled via EMG signals or a manual override panel to ensure safe, efficient, and natural operation. |
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