Wheels vs Continuous Tracks: Advantages and Disadvantages

Sometimes is very difficult to choose between wheels and tracks when you build a robot because each system provides certain features and performances. More than that, each system has its strengths and weaknesses.

In this article, you can find a series of lists with advantages and disadvantages for both wheels and continuous tracks. With all these positions in mind, you have to choose the best system for your robot.

Choosing the best system depends on several factors including here the traction, ground pressure, suspension, and steering.

The traction is greater if you use tracks instead wheels, but for the best results this depends on the terrain.

If you want a less ground pressure, you have to choose the tracks. The tracks have a lower ground pressure than wheels and are more suited to soft surfaces. For soft surfaces can be used larger tires, but these has limits and cannot work in all conditions – for example on snow.

Building suspension for tracked robot is more complicated than for a wheeled robot. The suspension system has an important role related to traction by keeping the tracks or wheels on the terrain.

The wheels have a significant advantage in steering compared to tracks, and this can be translated into a good maneuverability for the wheels.

Wheels vs Continuous Tracks

Wheels vs Continuous Tracks (image source)

Wheeled robots vs. tracked robots is a well-known subject under debate for a long period of time. In the following, you can find the advantages and disadvantages of both vehicle propulsion: wheels and continuous tracks.

Advantages and disadvantages using wheels

The wheels are everywhere in robotics and is one of the main components that facilitates the movement by reducing the friction. Most robots are designed with 3 wheels, 2 motors and 2-speed controllers. This is the most common structure for a robot designed for a simple structure, to move quickly, easily controlled, spin on the spot, or turn around in small places.

In general, wheels are used for:

  • low production costs – this is the case if we compare the prices for wheels and tracks;
  • speed – compared with tracks, the wheels need a lower amount of torque to move on from stationary;
  • maneuverability – the wheels provide high maneuverability compared with continuous tracks. The tracks are very difficult in maneuverability;
  • lightweight – continuous tracks are much heavier than wheels, and this is the main reason why wheels are used especially in cases when the mass of the robot is a critical property – for example, space exploration missions;
  • simplicity – a wheel has less moving parts, which means that there are fewer components that can get damaged;
  • materials – several materials can be used to build wheels that meet environmental conditions;

Disadvantages using wheels

Using the wheel, is not always the best case. There are some situations where the wheels are not the best choice.
In general, wheels are not used when:

  • drive over obstacles – depending on the terrain, a robot needs to pass small or large obstacles. For a wheel to get over a vertical obstacle, it has to be at least twice as tall as the vertical obstacle;

Advantages and disadvantages using continuous tracks

The continuous band of treads driven by a series of wheels is used when the wheels cannot be used. In this area can be added a variety of scenarios, including the move on uneven terrain or when it’s needed high traction.
In general, continuous tracks are used for:

  • power efficiency – compared with wheels, continuous tracks have high performance and optimized traction system, which is a plus in power delivery efficiency;
  • traction – the traction is high even on slippery surfaces like snow or wet concrete;
  • moving on rough terrain – using continuous tracks, a robot can operate on rough terrain while the wheels can get stuck. Also, the continuous band of treads can ascend and descend stairs, surmount obstacles, or cross ditches;
  • aesthetics – the tracks look more aggressive than wheels;
  • ground impact – a robot that moves on rubber tracks has a lower PSI on the ground. That means a less impact on the ground, especially when the robot is heavy;
  • weight growth potential – a robot with continuous tracks has a weight spread over the entire surface of the track. This is one of the reasons that a robot with rubber tracks support a heavy load;

Disadvantages using continuous tracks

In general, continuous tracks are not used in cases of:

  • lower speed – due to more friction and a complex mechanical system, the robots with continuous tracks has lower speed compared with robots on wheels;
  • less maneuverability – robots on tracks are less precise in maneuverability and require more power when turning;
  • easily break – the continuous tracks can be easily broken or dislodged than wheels;
  • short life – rubber tracks have a running time much smaller than the wheels;
  • difficult to repair – the continuous tracks are difficult to repair or replace than wheels;


Resources:
Wheels vs Continuous Tracks (Tank Treads);
Tracked Robots;
Tracks vs. Wheels;

This article was last modified on 14 May 2015.

  • Posted in: Robot Parts

3 comments » Write a comment

  1. For transportation technology, I have always used NASA as a guide. Why do they use wheeled vehicles?

    Tracked vehicles are the equivalent of having but two wheels on a vehicles. If part of one track is impeded, the vehicle is essentially impeded.

    With a multi-wheeled (usually six) vehicle there is much more resistance to being stopped. One of our designs can even traverse a test course in which part is covered with pig-pen wire suspended four inches from the ground.. This wire has squares of some four or six inches which usually trap most smaller vehicles. The iRobot fails some wiire tests, too.

    Most of our robotic platforms now have ‘paddles’ mounted concentrically with either the ultimate rear, or front, wheels and driven by separate motors. It is these paddles that permit the vehicle to be raised so that the wheels clear the wire squares.

    We also have electronic anti-slid drives on all wheels, which are driven independently of each other. The centre pair of wheels actually are made from stainless steel wire – hard on polished floors but just right for handling stairs and similar obstacles.

    Our latest product resembles an oversized oval rugby ball. It can travel over land and water. It is capable of carrying several sensors including video and infra-red. It also has the ability to turn in a 15 centimetre circle.

  2. I love that you brought up how tracks look more aggressive than a tire. It is so true, I mean imagine what a tank would look like with tractor wheels? In the future I am going to look into getting a tractor with tracks to plow the snow on my driveway because you gain more traction.

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