1. Introduction
The ARM-21N2 is a 6 Degrees of Freedom (DOF) metal robotic arm kit designed for enthusiasts, students, and researchers. This unassembled kit provides a robust platform for learning about robotics, mechanics, and servo control. Its all-metal construction and bearing-connected joints ensure durability and smooth operation. This manual provides essential information for assembly, operation, maintenance, and troubleshooting.
2. Safety Information
- This product is an unassembled kit and contains small parts. Keep out of reach of small children.
- Assembly involves handling electronic components and tools. Always exercise caution to prevent injury.
- Ensure all electrical connections are secure and correct before applying power to avoid short circuits or damage.
- Keep hands and loose clothing clear of the robot arm's moving parts during operation to prevent pinching or entanglement.
- Use appropriate power supplies as specified for the servos to prevent overheating or malfunction.
3. Package Contents
The ARM-21N2 kit is available in different configurations. Please verify your package against the list below:
- Frame Only Option:
- 1 x Set of Robot Arm Frame components (metal plates, fasteners, bearings)
- With 20KG Digital Servos Option:
- 1 x Set of Robot Arm Frame components
- 6 x 20KG Digital Servos
- With 25KG Digital Servos Option:
- 1 x Set of Robot Arm Frame components
- 6 x 25KG Digital Servos
Note: Control circuits, suction cups, grippers, and other accessories are NOT included and must be sourced separately.
4. Assembly Instructions
The ARM-21N2 robot arm kit requires assembly. Detailed assembly instructions are provided with the kit. Please follow them carefully. Below is a general overview of the assembly process:
- Unpack and Identify Components: Carefully unbox all parts and compare them against the provided parts list. Organize components to ensure easy access during assembly.
- Assemble the Base: Begin by assembling the base structure of the robot arm. Ensure all fasteners are tightened securely.
- Attach Servos to Frame Sections: If your kit includes servos, mount each servo to its corresponding arm segment using the provided screws and brackets. Pay attention to the orientation of each servo.
- Connect Frame Sections: Gradually connect the arm segments, forming the full 6DOF structure. Ensure that all movable joints are connected by bearings for smooth movement.
- Install the Gripper Holder: Attach the gripper holder to the end effector of the arm. This holder is designed to accommodate various end-effectors (not included).
- Wiring (General Guidance): Connect the servo wires to your chosen control board (e.g., Arduino, Raspberry Pi, or dedicated servo controller). Ensure correct polarity and pin assignments. Refer to your control board's documentation for specific wiring diagrams.
5. Operating Instructions
The ARM-21N2 robot arm is a mechanical platform. To operate it, you will need an external control system (not included). This typically involves:
- Controller: A microcontroller (e.g., Arduino, ESP32) or single-board computer (e.g., Raspberry Pi) capable of generating Pulse Width Modulation (PWM) signals to control the servos.
- Power Supply: A stable power supply appropriate for the number and type of servos used. Refer to servo specifications for voltage and current requirements.
- Software/Firmware: Custom code or libraries to control the individual servo motors, allowing for precise positioning of each joint. Inverse kinematics algorithms may be used for more advanced control.
- End-Effector: Attach a gripper, suction cup, or other tool to the gripper holder based on your application.
Each of the 6 degrees of freedom is controlled by a servo motor, allowing for a wide range of motion. Experiment with different servo angles to understand the arm's capabilities.
6. Maintenance
- Regular Inspection: Periodically check all screws, nuts, and bolts for tightness. Vibrations during operation can cause fasteners to loosen.
- Joint Lubrication: While the joints use bearings, light lubrication (e.g., silicone grease) on moving metal-on-metal contact points can help maintain smooth operation and reduce wear over time. Avoid over-lubricating servos.
- Cleaning: Keep the robot arm free from dust and debris. Use a soft, dry cloth for cleaning. Avoid using harsh chemicals or excessive moisture.
- Servo Care: Avoid continuously stalling the servos, as this can lead to overheating and damage. Ensure the arm's movements are within the servo's torque limits.
- Cable Management: Ensure all wiring is neatly routed and secured to prevent snagging or damage during movement.
7. Troubleshooting
- Arm Not Moving/Responding:
- Check power supply: Ensure it is connected and providing sufficient voltage and current.
- Verify wiring: Confirm all servo connections to the controller are correct (signal, VCC, GND).
- Inspect controller code: Ensure your code is correctly sending PWM signals to the servos. Test individual servos if possible.
- Check for mechanical obstructions: Ensure no parts are jammed or preventing movement.
- Jerky or Inaccurate Movement:
- Loose connections: Re-tighten any loose screws or connections in the arm structure or servo mounts.
- Power supply issues: Insufficient current can lead to erratic servo behavior.
- Servo calibration: Ensure your controller's PWM signals are correctly calibrated for the servo's full range of motion (500-2500usec pulse width for 180°).
- Servo Overheating:
- Reduce load: The arm might be attempting to lift or move too much weight.
- Check for binding: Ensure all joints move freely without excessive friction.
- Verify power supply voltage: Too high a voltage can cause overheating.
8. Specifications
General Robot Arm Specifications:
| Type | 6 Degrees of Freedom (DOF) Robotic Arm |
| Construction Material | Metal |
| Joints | All movable joints connected by bearings |
| Gripper Holder Compatibility | Fits suction cups, electromagnets, forks, craws, grippers, etc. |
| Head Length Limit | 66mm (2.6") |
| Forearm Length Limit | 156mm (6.1") |
| Upper Arm Length Limit | 131mm (5.2") |
20KG Digital Servo Specifications (if included):
| Servo Motherboard | Digital controller |
| Servo Size | 40 x 20.5 x 40.5mm (1.6 x 0.8 x 1.6") |
| Weight | 56g ±5% (0.1lb ±5%) |
| Working Voltage | 4.8-7.2V |
| Output Transmission | Metal gears + double bearings |
| No-load Speed | 0.14-0.18sec/60° |
| Stall Torque | 20.5kg.cm |
| Pulse Width | 500-2500usec |
| Rotation Angle | 180° |
| Dead Zone Width | 5usec |
| Midpoint Position | 1500usec |
| Output Shaft | 25T |
| Output Shaft Hole | M3 |
| Idling Current | 210-260mA |
| Blocking Current | 2100-2700mA |
| Waterproof Level | Preliminary |
| Shell Material | Aluminum alloy + plastic |
25KG Digital Servo Specifications (if included):
| Servo Motherboard | Digital controller |
| Servo Dimensions | 40 x 20.5 x 40.5mm (1.6 x 0.8 x 1.6") |
| Weight | 62g ±5% (0.1lb ±5%) |
| Working Voltage | 4.8-7.2V (instant 8.2V) |
| Output Transmission | Metal gears + double bearings |
| No-load Speed | 0.145-0.185sec/60° |
| Stall Torque | 25.5kg.cm |
| Pulse Width | 500-2500usec |
| Rotation Angle | 180° |
| Dead Zone Width | 5usec |
| Midpoint Position | 1500usec |
| Output Shaft | 25T |
| Output Shaft Hole | M3 |
| Idling Current | 220-280mA |
| Blocking Current | 2250-2850mA |
| Waterproof Level | Preliminary |
| Shell Material | Aluminum alloy (in red) + plastic (in black) |
9. User Tips
- Start Simple: When first programming the arm, begin with simple movements for each joint individually before attempting complex sequences.
- Power Management: Use a separate power supply for the servos and the control board to prevent voltage drops that can affect microcontroller stability.
- Experiment with End-Effectors: The versatile gripper holder allows for various tools. Experiment with different end-effectors like electromagnets or custom grippers to expand the arm's functionality.
10. Warranty and Support
For warranty information, returns, or technical support, please contact the seller directly through your purchase platform. Keep your order details readily available when seeking assistance.
