The spirit of innovation has been part of the automotive industry since its inception. It’s what created Henry Ford’s drive to mass-produce automobiles and, by doing so, forever changed the concept of industry. It’s what’s driving the current market focus on self-driving vehicles, spawning new innovation in a century-old industry.
Innovation can come from interesting collaborations, so it’s no surprise that recent innovation was borne out of the automotive and robotics industries working together. Robots are seen in the manufacturing process, and many of the scientific and math principles that go into the operation and engineering of a car also go into the operation and engineering of a robot. Even the simplest robot needs an engine, a steering mechanism and some wheels to become mobile.
By using familiar mechanical examples of a car, robotics coaches and math/science teachers can help students embrace more abstract engineering principles needed to successfully study and build robots. This article will look at some mechanical concepts and how they relate to cars and robots, providing a resource for teachers and a source of inspiration for up-and-coming engineering students.
Mechanical Principles of Cars & How They Relate to Robots
Both cars and robots have mechanical parts that are quite similar, and they are both controlled to some extent by a human operator or driver. Some of the mechanical principles found in cars easily translate into robotics and the building of robots. Here are some of them:
Servomotors and Other Motors
When most people think of a car, they think of a gas-powered vehicle run by an engine. This doesn’t readily connect to the robotics industry. However, electric vehicles run on a motor and are powered by a battery of some sort, rather than the power of fuel. Most robots also use electric motors to function.
Motors take electrical energy and convert it into mechanical energy. The electrical energy typically comes from a battery – though in robotics, the source may be a cord plugged into an outlet as well.
In the car industry, there are three types of electric motors. These are:
- Brush DC (direct current) Motor – This motor uses two magnets facing the same direction surrounding two coils of wire. The coils conduct electricity delivered via brushes, which generates a magnetic field and pushes them away from the magnets, causing the rotor to turn.
- Brushless DC Motor – This motor works on a similar technology, but lacks the brushes. These motors contain a permanent magnet and an electromagnet. When the electromagnet is charged, the polarizing forces of the two magnets cause the motor to spin.
- Induction Motor – The induction motor is also called an AC (alternating current) motor. This motor uses electromagnetic induction to spin, and is more powerful than most DC (direct current) motors.
The automotive industry uses all three types, but Tesla, one of the leading manufacturers of electric cars, leans toward the Induction Motor.
In the robotics industry with its smaller servomotors, DC is the more common source of electricity. Since electrical components within most robots use DC, this ensures compatibility and makes the build more convenient. AC works best when a high level of torque is required or when the robot can stay plugged into the wall outlet, but most robotics competitions feature robots that run on DC.
For more information about motors and the way they connect to robotics cars, visit:
- Electrical Engineering – Why Does a Tesla Car Use an AC Motor Instead of a DC One?
- Engineers Edge: Types of DC Motor Connections
- Instructables: Complete Motor Guide for Robotics
- Georgia State University: Hyperphysics – DC Motor Operation
- Clark Science Center: Motor Fundamentals
- Buffalo State University: Analyzing Simple Electric Motors in the Classroom
Pulleys and Belts
A pulley takes a collection of wheels (gears without teeth) with a belt or rope looped across them to make objects easier to lift, move items or create motion to run a device. This transfer of torque (a twisting force that tends to cause rotation) has many applications in both the automotive and the robotics industry.
Cars have several types of pulleys, which can operate accessories, provide power, or create a path for the car’s belt. The easiest one to understand is the automotive cooling fan drive. This drive uses a smooth pulley, connected to the engine’s crankshaft, to transfer torque, to the pulley on the cooling fan, spinning the fan and cooling the car. Throughout a car’s engine, there are several pulley and belt systems that run many different components.
How does this translate to robotics? Like cars, robots need to transfer motion from the engine to a component. This can be done by belts and pulleys that transfer torque. Robots can use one of four basic types of belts, which are:
- Round belts
- Flat belts
- Toothed belts
Using pulleys and belts seems simple at first, but the robotics classroom will need to consider these tips when deciding what to use:
- Pulleys of the same diameter rotate at the same speed.
- Mechanical advantage and velocity ratio are gained when one pulley is larger than the other.
- A large drive pulley driving a smaller driven pulley will result in faster speed on the driven pulley, and vice versa.
For more information about pulleys, cars and robots, visit:
- Explain That Stuff: Pulleys
- Your Mechanic: How Belt Pulleys Work
- Your Mechanic: Understanding All of the Drive Belts in Your Car
- RobotPark Academy: Pulleys and Belts
- Teaching Engineering: Powerful Pulleys
- New England Ropes: Mechanical Advantage of Pulleys (Video)
Gears and Chains
Gears and chains in a car work on the same mechanical principle as pulleys and belts: using turning motion to transfer torque from one area to another. Gears can increase speed, increase force or change the direction of a force. While cars have a number of gears, the main ones are those that transmit power from the crankshaft (the rotating axle powered by the engine) to the driveshaft (the shaft under the car that turns the wheels).
Gears are necessary to change the speed from the pistons, which push up and down 1000 times every minute, to the wheels, which rotate at various rpm depending on how fast the car was going. Without gears, all cars would instantly run at around 75 mph (1000 rpm) at the slowest speed. Gears change the speed of the rotation to keep the car safe. To ensure a safe speed, cars have a box full of gears, known as a gearbox, that sits between the driveshaft and crankshaft. Some older cars also have timing gears and chains, instead of pulleys and belts.
In robotics, gears perform the same job – transferring motion from one part (often the engine) to another (often the moving part). The ratio between the number of teeth on the input or driven gear and the output gear is how the torque and speed of the output gear can be determined. So, when building a robot, robotics teams and innovators should choose gear size and number of teeth based on the desired output speed and the known input speed. This is all based on the concept of mechanical advantage.
For more information about gears and how they relate to robotics and cars, visit:
- Rho Beta Epsilon WPI Robotics Wiki: Gears
- Society of Robots: Robot Gears Tutorial
- Bowles Physics: Gears and Gear Ratios
- Robotics Tomorrow: Harmonic Drive – A Guide to Choosing Gears for Robotics
- The University of Georgia: Gears – Math in Context
- Storming Robots: Applied Physics – Gears Math
- Mathematics Stack Exchange: Determining the Ratios Needed in Gear Reduction
- Baldwin Wallace University: Gear Math
All cars have wheels. Not all robots move on wheels, but many have wheels somewhere in their overall design. Understanding how wheels works is critical to creating a working, functional robot.
In a car, a wheel is connected to an axle. The axle spins on an axis, passing its mechanical rotational energy to the wheels. As the wheels rotate, they convert that energy to mechanical motion.
In robotics, wheels are preferred when speed, accuracy and stability are all required to move the robot. Wheels can be standard, orientable, ball, and omnidirectional with the underlying goal to move the robot from one place to the next. In a robot, unlike a car, the wheels themselves can actually guide the direction of movement without a steering wheel turning them. Robots with differential wheels move based on the motion of two separately driven wheels on either side of their body, changing the direction by varying the rate of rotation of each wheel individually.
For more information on wheels in both cars and robots, visit:
- MathWorks: Wheel and Axle
- Take Me Beyond the Horizon – The Numbers Behind Wheels + Tires – Wheels First
- Mathalicious: Spinning Your Wheels
- RobotShop: What Wheels Should My Robot Use?
- Robot Platform: Types of Robot Wheels
- Robot Platform: Wheel Control Theory
While wheels make a robot or a car move, a steering system is critical for the direction of that movement. Most cars use the Ackermann wheel configuration, made up of two steerable wheels in front and two non-steerable wheels in the rear, with at least two of the wheels being motorized. It would be unusual to find a car with a different configuration than this, because it works very well for its purpose. This configuration provides:
These three factors should also be considered when designing a mobile robot. However, in the case where alternative mobile applications exist, there are several other wheel configurations to adapt from.
For more information on wheel configurations and steerable wheels, visit:
- Sven Bottcher: Principles of Robot Locomotion
- Ackerman? Or Not? Does It Matter?
- Hot Rod Network: Ackermann Steering System – Ackermann Technology Revisited
- Dynamics: Steering Geometry
- Vexmen: Choosing Your Robot’s Base
Electrical Principles of Cars & How They Relate to Robots
Cars, even those that run on gas, have electrical components. Those components work by sending an electrical signal through a circuit to receive and distribute power from the car’s sensors to its central computer. This controls engine function and how well the engine burns its fuel.
Robots also have electrical components that work in a similar fashion. Even with a surface level understanding of a car’s electrical components, students can translate that knowledge when designing the electrical components of a robot.
A circuit board provides the path through which the electrical current can safely flow, in order to reach the various moving parts of a vehicle or robot. Circuit boards have four basic components. These are:
- Power – Power is the energy required to do something (per unit time). In a circuit, it’s the flow of electrons and is measured in the voltage times the current. Power flows from the source (positive terminal) to the ground (negative terminal). Power often comes from a battery in a simple circuit. Even in a car, the battery provides the power.
- Resistors – Resistors resist electron flow and affect the amount of current, the power usage and the voltage sent through the circuit.
- Capacitors – Capacitors store electrons during times when the current is running high and the battery can’t keep up.
- Diodes – Diodes keep current flowing in one direction only, which ensures your circuitry is protected.
In a car, the circuit board and engine control module (ECM) or engine control unit (ECU) are critical to provide energy. They sense errors and control the fuel, air, and spark in the engine, constantly making adjustments to ensure the car is operating correctly. The ECM also stores codes when the engine isn’t working properly so the technician can adjust appropriately.
In robotics, the circuit board delivers the signals sent by the controller to ensure the robot functions as desired. The electricity flowing through the circuit board will power the various actions as directed by the operator. In complex or autonomous robots, some of these actions are automated and controlled by a central computer, just like the engine control module in a car. For more information about these, visit:
- How Stuff Works: How the Engine Control Module Works
- How to Build a Robot: All About Circuits
- Society of Robots: Basic Electronics Components Tutorial for Robots
- How Stuff Works: How Circuits Work
Sensors in a vehicle detect those factors that are critical to operation. This can include everything from oil pressure to coolant level. Your sensors, and the reports they send to the computer, help keep your car functioning safely. They monitor major systems and send real-time signals to the computers on the car to track systems and alert drivers to problems. The most common sensors are:
- Crank position sensor
- Cam position sensor
- Engine coolant temp sensor
- Manifold absolute pressure sensor
- Throttle position sensor
- Accelerator pedal position sensor
- Heated oxygen sensor in the exhaust
- Wheel speed sensor
- Tire pressure sensor
- Intake and ambient air temperature sensor
Modern electric and autonomous cars have even more sensors. In an electric car, sensors are necessary to track the overall performance. In a hybrid, sensors help the on-board computer determine when to switch from battery to fuel operation. In an autonomous car, vision and proximity sensors help prevent crashes.
In a robot, sensors measure the configuration of the robot and the condition of the environment. They send this information to the controller through electrical signals passed through the circuit board. Sometimes, robotic sensors can sense things not seen by the human eye, such as radiation, imperceptible movements, or actions that take place in the dark. Types of sensors used in robots include:
- Vision and light sensors
- Sound sensors
- Force sensors
- Proximity sensors
- Tilt sensors
These sensors gather information, send it back to the computer through the circuit board and allow the robot to take action accordingly.
For more information about sensors, visit:
- Mobil: Understanding Your Vehicle’s Sensors
- Argonne National Laboratory: Automotive Vehicle Sensors
- Sensors Web: Car Sensors
- Robohub: Sensors for Autonomous Driving
- Robots for Roboticists: Sensors Driving the Uber Self-Driving Car
- Robot Platform: Types of Robot Sensor
Robot Car Projects for Students
The electrical similarities between cars and robots are clearly indicative of a connection between these two areas of study. In fact, there are a number of projects students can tackle to further investigate this relationship. Consider these:
- Design News: GoPiGo Turns a Raspberry Pi Into a Robot Car – This project contains a circuit board, motors, sensors, microcontrollers, LEDs and encoders. It also contains all the hardware necessary to build the car. The car is powered by a Raspberry Pi.
- Robotics Wonder How To: Make a Robot Car – This tutorial walks students through the process of building a robot car from scratch.
- Make Use Of: How to Build a 4WD Arduino Robot for Beginners – This PDF tutorial teaches how to build a self-driving robotic car using a 4WD kit from AliExpress. This project is available in a PDF download format.
Computer Programming in Cars and Robots
Because both robots and cars have computers, they require a basic understanding of computer programming. In fact, building a robotic car is often the first step for computer science students into the field of robotics. This process shows them the overlap between programming and robotics, and can help broaden students’ interest.
So how does the computer inside a car work? Before we jump into examples, here are some things to remember:
- It’s a computer network – Drivers are often surprised to learn that their cars are mobile computer networks.
- It has a Controller Area Network – The CAN bus, more specifically, is the connection of wires and software that connects the car’s computers and sensors.
- Cars contain many Electronic Control Units – A car’s “computer” isn’t like a PC, but rather is a system of small computers, or ECUs. ECUs each control a specific function, whether it’s controlling the fuel process or rolling up the windows.
- Sensors track data, send it to the ECUs, which travels through the CAN bus network – This sounds complicated, but here’s how it works. Sensors in various parts of the car collect data, which the ECUs need. The CAN bus network provides a path for that data to flow from the sensors to the computer. When the computer receives the data, it makes a decision and selects an action for the car’s system.
- CAN bus eliminates the need for complicated wiring – The CAN bus network was developed in the mid-80s, and it eliminated the need to run wires every time an electronic feature was added to the car, focusing instead on software to ensure these connections are made. This effectively shrank the car’s wiring harness.
Here’s a practical example: a car’s sliding door function operates on a computer network. When the network’s sensors detect a spike in voltage, because something is blocking the easy path of the door, the ECU sends an instantaneous signal through the CAN bus network to reverse the motion of the door, protecting the protruding leg or arm.
In a robot, programming is typically the final step, and a mobile robot’s computer works in much the same way that a car’s computer does. While the actions of a robot’s computer may be governed by a larger off-site computer (known as microcontroller, or tethered controller), a similar series of sensors and network communication takes place inside a robot. Once the actuators, electronics, sensors and other features of the robot are in place, the student is ready to program it.
Here are some reminders for when it’s time to build the ‘bot:
- Robots need a language – Robotics students much choose a programming language for their robot. C/C++, Java and Python are the three most popular. C is the one used most often in cars and robotic cars. The language of the microcontroller will dictate the language the robot uses.
- When programming a robot, use manageable chunks of functional code – Make sure to document everything by commenting on the sections of code saved on your computer, so you know what segment you need for a particular action.
- Make a code for each action – Each action you want the robot to do requires its own code. Learning about subroutines can help limit the string of code, but at first students will want to create code for every action.
- Like a car, sensors detect data, send it to the computer and create action as a result – The code just allows the robot to make the right action based on the data collected, but the basic process of sensor, data, decision and action remains the same.
Feeling a little lost? Don’t worry – here’s a quick example: a robotic car with a distance sensor can be programmed to travel a certain distance. When the robot has traveled that distance, the sensor sends a signal to the wheels to stop moving. The microcontroller is used to program in the desired distance.
Because the coding already used in cars is fairly universal, it’s a good launch point to dive deeper into applications for computer programming in robotics. To learn more about this, visit:
- Popular Mechanics: How the Computer Inside Your Car Works
- RobotShop: Programming Your Robot
- Udacity: Programming a Robotic Car
- Toptal: An Introductory Robot Programming Tutorial
- Sebastian Thrun: Programming a Robotic Car (Video)
- Python Programming: Robotics with the Raspberry Pi
Mathematical Principles of Cars as they relate to Building Robots
Everything about designing the function of a car – from horsepower to displacement to compression ratios – requires a basic understanding of math. Here are some basic math concepts many engineers have to consider when building a car:
- Torque x RPM / 5,252 = Horsepower – This equation makes it possible to find the torque or the horsepower at any given RPM, so you know exactly how powerful your vehicle is.
- RPM x engine displacement / 3456 x 0.85 = cubic feet per minute – This equation will help those building cars determine which carburetor size is right for their vehicle.
- Displacement = bore x bore x stroke x 0.7854 x number of cylinders – Calculating displacement is helpful, and easily done when you know the bore and stroke of the engine using this formula.
- Effective Gear Ratio = (original tire diameter / new tire diameter) x gear ratio – Adding big tires changes the gear ratio, and the bigger the tire the slower the acceleration. In this case, understanding the math will prevent car owners from making a mistake.
- Stopping a Car – The faster a car goes, the more distance it requires to stop. This is figured using two equations: energy = mass x velocity2 and distance = 2.2 x velocity + velocity2/20. Knowing the mass of the vehicle and its vector speed allows for the calculation of its energy, and knowing the energy allows for the calculation of stopping distance.
- Mathematics of parking cars – This one doesn’t have a cut-and-dried equation, but math can be applied to driving as well as the manufacturing and upkeep of cars. For example, with carefully applied math, cities can estimate within reasonable accuracy the number of cars that can be effectively parked on any of their streets.
- Physics of Turning Cars – When a car turns, geometry and physics equations determine the new angle that the car will travel and how far the car needs to turn to get where it intends to go. While complicated, these calculations are necessary to understand when determining a car’s performance, particularly for race cars.
- Speed Ratios – A car’s speed depends on its horsepower, weight and wheel diameter. These ratios will determine the tops speed a car can go.
Many of these equations translate into robotics as well. Here’s how:
- The same mathematical principles used to parallel park cars can also be used to move and position robots.
- Robots have gears and wheels, and although acceleration may not be the goal, understanding gear ratio is still helpful.
- A robot’s speed can also be determined using similar ratios as those used in cars, though power won’t be measured in “horsepower” for many robotics applications.
- The physics of turning a car is quite similar to the physics of turning a robot, though the speed will be slower.
- A high-speed robot will also need to be given stopping distance, just like a car.
For more information about mathematical principles in the design of cars and robots, visit:
- Prezi: Math in Racing Cars
- Matific: Car Designers Need Math
- Roadkill Customs: Popular Automotive Math Formulas and Conversions
- HiPerMath: Engine and Car Physics
- NASA: Calculator Controlled Robots
- Mathematical Association of America: Mathematics and Robotics
- BCIT Commons: Robotic Arm Coordinates and Geometry
The Future of Robotics, Cars & Car Design
As the automotive industry moves forward, the future seems to indicate a stronger collaboration between robotics principles, cars and car design. Cars are already becoming increasingly autonomous through their on-board computer systems, while autonomous robotics is growing in popularity and scope. It’s not so crazy to believe that the two will likely be merging in the future.
The Self-Driving Car
The self-driving car is the ultimate merger between robotics and cars. The self-driving car is an incredibly complicated computer-controlled robot, using sensors to do everything from drive a projected route to avoid a collision with a pedestrian. Here are some facts about the future of the self-driving car:
- By 2040, experts believe autonomous vehicles will comprise 25 percent of the global vehicle market.
- Regulation, not the technology itself, is the main roadblock to the launch of driverless vehicles.
- Driverless vehicles use sensors to prevent collisions, and may actually be less risky than human-driven vehicles.
- “Dangerous” drivers could still use cars when driverless vehicle technology becomes mainstream.
- The combination of math and driverless vehicles could put an end to traffic jams – although studies show this will not affect overall productivity.
- Decline in the number of crashes and the amount of congestion is possible with just 10 percent of vehicles changing to autonomous vehicles.
- Uber launched its first self-driving fleet in 2016, and GM will be launching the largest in 2017.
In light of these facts, it’s a safe bet that the next decade is likely to be the decade of the self-driving car.
Americans with Disabilities Act Considerations for Cars
Robotics may make it easier for disabled individuals to enjoy the autonomy of a vehicle. Those who can’t manage the pedals or steering wheel can use robotics to maneuver the necessary gears. Those in wheelchairs already frequently rely on robotic lifts to get them into their cars. Here’s a look at the future of ADA cars.
- Vehicle Production Group has plans to make the first-ever car built specifically for those in wheelchairs. This eliminates the need to convert a standard van into an accessible van, and will include features that make traveling in a wheelchair much easier.
- Eye-tracking technology, combined with robotics, could provide paralyzed individuals with the ability to drive, though this technology is still in the far future.
- Should autonomous vehicles become reality, it will provide transportation for people with disabilities of all types, including blindness.
- Wheelchair-friendly Compact Electrical Vehicles could allow those with disabilities even easier access to transportation.
Robotics Applications in the Automotive Industry
The future of cars will be directly tied to the future of robotics. In fact, these two industries are already quite intertwined, from the basic conception of a vehicle and its moving parts to the manufacturing process, and even its commercial use. Here are some more robotics applications that will have a specific impact on the future of the automotive industry:
- Giving Robots “Eyes” – Robotic vision, or giving robotic arms “eyes” (vision sensors), allows for better precision in the installation of parts on the body of a car. This allows for a proper offset on robotically-installed parts, and a more precise fit. Any small difference on the vehicle as it goes down the assembly line is accounted and adjusted for when placing on the next part.
- Collaboration – Robot-to-robot collaboration is making automotive production lines more productive. When handling robots and welding robots, for example, can interact with one another, and so the entire welding process occurs more quickly and error-free. Collaboration between robots and humans is also increasingly common, with robots performing tiresome repetitive tasks while humans oversee and direct the actions – again, minimizing error and increasing consistency.
- Robotic Assistance for Hand Performed Tasks – While robots have greatly changed the manufacturing process, they haven’t replaced the human component altogether. Many assembly tasks are still performed by people. The robotic hand device can reduce stress from repetitive movement while increasing the gripping force of the line worker. This increases dexterity and reduces joint fatigue.
- Robotic Paint Application – Applying vehicle paint using robotic arms is the go-to method, but innovations continue to make this process more efficient. Robotic paint application reduces the risk to workers by minimizing exposure to toxic paint. It also protects the integrity of the finished product by ensuring more consistent results.
The self-driving car, additional innovations for the disabled, and ongoing innovations in the manufacturing process show the continued need to study robotics and their implication for the automotive field. For more information on these topics and the math behind them, visit:
- Brookings: Driverless Cars Are Coming – Here are 8 Useful Facts About Them
- The Economist: How do Driverless Vehicles Work?
- Motherboard: Driverless Cars Can Never Be Crashproof Physics Says
- Techopedia: 5 Technological Innovations That Seek to Enable the Disabled
- Smart Chair: Disability Advocates See Opportunity in Self-Driving Cars
- Phys.org: The Future Is Now for Robot Cars
Robotics and Engineering Competitions to Consider
Are you feeling inspired? Why not take what you’ve learned and apply it! There are dozens of opportunities for both high school and college students to compete in robotic competitions around the world. Check ‘em out!
- FIRST Robotics Competition
- VEX Robotics World Championship
- Sparkfun: Autonomous Vehicle Competition
- 25th Annual Intelligent Ground Vehicle Competition
- International Autonomous Robot Racing Challenge
- BEST Robotics
- International Robot Olympiad
- Human Powered Vehicle Challenge
- Formula Student Engineering Contest
- Formula Hybrid Competition
- American Society of Mechanical Engineers Design Competition
- National Robotics League Competitions
- National STEM League – Innovators in Training
- Solar Car Challenge
- Robotraffic Annual International Competition
- Case School of Engineering Competitions
- Chem-E-Car Competition
- A. James Clark School of Engineering Mechanical Engineering Student Competitions
- TEN80 Student Rover Challenge
- Autonomous Robotic Vehicle Project Contests
- Robot Stock Car Autonomous Racing
- Autonomous Robots Lab: Robotic Competitions
- MIT: Autonomous Robot Design Competition