Mg996r: A Brief Introduction into Its Working and Applications

What is the Mg996r Servo?

The Mg996r is a high-torque servo motor commonly used in robotics, RC vehicles, and other applications requiring precise position control. It is an upgraded version of the popular Mg995 Servo, offering improved performance and durability.

Some key specifications of the Mg996r servo include:

Specification	Value
Operating Voltage	4.8-7.2V
Stall Torque	9.4-11 kg/cm (at 4.8V)
Operating Speed	0.17-0.13 sec/60° (at 4.8V)
Gear Type	Metal
Rotation	0°-180°
Dimensions	40.7 x 19.7 x 42.9 mm
Weight	55g

The high stall torque allows the Mg996r to handle heavier loads and resist external forces without losing its position. The metal gears provide strength and long-term reliability compared to plastic gears found in lower-end servos.

How Does the Mg996r Servo Work?

Servo Motor Basics

A servo motor is a type of motor that allows for precise control of angular position. It consists of a DC motor, gear reduction unit, potentiometer for position feedback, and control circuit.

The control circuit compares the desired position (input signal) with the actual position (from the potentiometer) and adjusts the motor accordingly to align the output shaft to the commanded position. This feedback system enables servos to achieve high accuracy and hold a set position even under load.

PWM Control

The Mg996r, like most hobby servos, uses Pulse Width Modulation (PWM) signals for position control. A standard servo PWM signal has the following characteristics:

• Frequency: 50Hz (20ms period)
• Pulse width range: 1-2ms
• 1ms pulse = 0° position
• 1.5ms pulse = 90° position
• 2ms pulse = 180° position

By varying the pulse width between 1-2ms, the servo can be commanded to rotate to any angle within its 0-180° range. The control circuit handles translating the PWM signal into the corresponding shaft position.

Controlling the Mg996r

Arduino Example

To control the Mg996r servo with an Arduino, you’ll need to:

1. Connect the servo to the Arduino
2. Brown wire (GND) to GND
3. Red wire (VCC) to 5V

4. Orange wire (Signal) to a PWM pin

5. Use the Arduino Servo library to generate the appropriate PWM signals

Here’s a simple Arduino sketch to sweep the Mg996r servo from 0 to 180 degrees:

#include <Servo.h>

Servo myservo;  // create servo object 

void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 
}

void loop() {
  for (int pos = 0; pos <= 180; pos += 1) { 
    myservo.write(pos);    // move to position in degrees
    delay(15);            // waits 15ms for servo to reach position
  }
  for (int pos = 180; pos >= 0; pos -= 1) { 
    myservo.write(pos);   // move back to 0 degrees
    delay(15);
  }
}

This code creates a Servo object, attaches it to pin 9, and then uses a for loop to progressively increase the position from 0 to 180 degrees in 1-degree steps. Another loop then moves it back to the starting position. The delay(15) gives the servo time to physically rotate to each new position before the next increment.

Other Control Methods

In addition to Arduino, the Mg996r can be controlled by any microcontroller or system capable of generating PWM signals in the appropriate format, such as:

• Raspberry Pi
• STM32
• PIC
• 555 Timer Circuits
• Dedicated servo controllers

The specific implementation will vary depending on the platform, but the underlying principle of using PWM signals to set the position remains the same.

Applications of the Mg996r Servo

Robotics

Servos like the Mg996r are extensively used in robotics for actuating joints, grippers, and other moving parts. Their high torque and positional accuracy make them suitable for applications such as:

• Robot arms and manipulators
• Walking/crawling robots
• Pan-tilt camera mechanisms
• Steering systems
• Animatronics

Multiple servos can be combined to create complex movements and perform tasks like grasping objects, walking, or gesturing.

RC Vehicles

In radio-controlled vehicles, servos are used for controlling the steering (cars/boats) or flight surfaces (planes/drones). The Mg996r’s high torque is beneficial for larger models or those operating under heavier loads. Possible applications include:

• Steering servos for RC cars and trucks
• Rudder, elevator, aileron servos for planes
• Collective pitch and cyclic servos for helicopters
• Gimbal stabilization for RC camera drones

Other Uses

Beyond robotics and RC, the Mg996r can be used in any project requiring precise, automated position control:

• Automated door locking mechanisms
• Solar panel tracking systems
• Motorized camera sliders and dollies
• Autofocus and zoom control for cameras/projectors
• Valve and flap control in industrial settings

Its 180-degree rotation range, high torque, and ease of control make it a versatile choice for many applications.

Mg996r Servo Alternatives and Variations

While the Mg996r is a popular choice, there are many other servos available with different specifications to suit various needs:

• Sg90: A micro-sized 9g servo with less torque but faster speed, suitable for smaller projects.
• Ds3218: A high-voltage, giant-scale servo with 20kg+ torque for heavy-duty applications.
• Mg92b: A micro metal gear servo similar to the Sg90 but with a durable metal gear train.
• Hs-422: A deluxe servo with dual ball bearings and a carbonite gear set for extra robustness.
• Es08maII: A nano-sized 8.5g servo for applications with very limited space.

Continuous rotation servos are also available, which can spin indefinitely in either direction instead of having a limited rotation range. These are useful for driving wheels or creating simple motors.

Frequently Asked Questions (FAQ)

1. What is the difference between the Mg996r and Mg995 servos?

The Mg996r is an upgraded version of the Mg995 with improved performance and durability. It has a higher stall torque (9.4-11 kg/cm vs 8.5-10 kg/cm), slightly faster speed, and an all-metal gear train compared to the Mg995’s metal and plastic hybrid gears. The Mg996r is generally recommended over the Mg995 for most applications.

2. Can the Mg996r be used with a 3.3V microcontroller?

The Mg996r has an operating voltage range of 4.8-7.2V, with 6V being the nominal voltage. While it can run on voltages as low as 3.3V, the torque and speed will be significantly reduced, and it may not perform reliably. For best results, power the Mg996r with a voltage within its specified range, and use level shifting or a separate power supply if necessary.

3. How much current does the Mg996r draw?

The current consumption of the Mg996r depends on the load and operating voltage. At 6V with no load, it typically draws around 10-15mA. However, when stalled (i.e., under maximum load), the current can spike up to 1-1.5A or more. It’s important to use a power supply that can handle these peak currents and to be cautious when using multiple servos to avoid overloading the supply.

4. What is the lifespan of the Mg996r servo?

The lifespan of a servo depends on factors like usage conditions, load, and operating environment. The Mg996r’s metal gears give it improved durability over plastic-geared servos, but it can still wear out over time, especially if subjected to high stress or operated near its limits. Under normal use, you can expect it to last for several hundred hours of operation or tens of thousands of cycles. Regular maintenance, like cleaning and re-greasing, can also help extend its lifespan.

5. Can the Mg996r be modified for continuous rotation?

Yes, like most standard servos, the Mg996r can be modified for continuous rotation. This involves disassembling the servo, removing the position feedback potentiometer, and modifying or replacing the control board. There are tutorials available online detailing the process. However, it’s worth noting that modifying the servo will void its warranty and may affect its performance and reliability. If you need continuous rotation, it’s often better to purchase a dedicated continuous rotation servo instead.

Conclusion

The Mg996r servo is a versatile and reliable choice for a wide range of applications requiring precise position control. Its high torque, metal gears, and standard size make it well-suited for use in robotics, RC vehicles, and other projects.

By understanding how the Mg996r works and how to control it using PWM signals, you can effectively integrate it into your own designs and take advantage of its capabilities. Whether you’re a hobbyist or professional, the Mg996r is a valuable addition to your servo motor toolkit.