Key Technologies Defining Robotics – Mobility and Dexterity

17-12-2020 | By Mark Patrick

What will the series cover?

In this series of six blogs, we look at the key technologies defining the way robots are being designed and used today, and how that may evolve in the future. It will cover developments at the hardware and software level and how innovations such as AI are already shaping robotics' future.

Blog 1: Key Technologies Defining Robotics – From Static Arms to AMRs

Blog 2: Key Technologies Defining Robotics – Mobility and Dexterity 

Blog 3: Key Technologies Defining Robotics – Positioning and Navigation 

Blog 4: Key Technologies Defining Robotics – Robot Operating Systems

Blog 5: Key Technologies Defining Robotics – CoBots and AI

Blog 6: The Future of Robotics 

Mobility and Dexterity

Movement is part of robotics, based on principles discovered over 100 years ago. Electric motors turn potential energy into mechanical work. Engineers understand how this happens and continue to make improvements, both in functionality and efficiency. 

Motor control is a very active area of research. All leading semiconductor vendors are developing new devices that deliver more efficient motor control. Each movable part of a robot will need some form of motor. 

Some robots have parts that are similar to humans, such as:

  • arms 

  • wrists

  • hands

The primary forms of motion used include:

  • Vertical, radial, and rotational movement for the arm(s)

  • Pitch, roll, and yaw for the wrist(s)

Locomotion, or the ability to move from one place to another, also requires motors. The size and power of the motors will vary massively, depending on the type of locomotion. A robot designed to move along a production line on rails could use simple motors. A walking robot uses what we could consider legs.

The Types of Motors Used in Robotics 

The type of motors used will range from AC motors when torque is important, to stepper motors when more angular control is needed. In between, the choice includes brushed DC motors, which are cost-effective and straightforward, but also inefficient and prone to wear. The modern alternative is likely to be brushless DC motors, as they can be more efficient when appropriately driven (see below) and have no brushes, so are have less wear over time. 

Industrial automation has used Robots for nearly 70 years. The earliest robots had good mobility and could move one limb around a fixed base – ideal when used on assembly lines to move objects from one position to another. 

Modern robots have more capability and can also manipulate objects, rather than only move them. This increase in dexterity comes from copying the way the human hand functions. Robot hands now use tendons to join muscles to bones.  The following section is a simple description of where research is going. 

Examples of Robot Hands in Action

One notable example comes from qbrobotics with its qb Softhand Industry. The company claims this is the first anthropomorphic robot hand, designed for use in industrial applications. Despite having five 'fingers' with 19 degrees of freedom, it uses just one motor to control the tendons. 

What is impressive and a clear indication of the company's direction is that the qb Softhand Industry is designed to be 'plug and play' with leading brands of static robots, including:

  • Universal Robots

  • ABB

  • Kuka 

  • Franka Emika

  • Doosan

Meaning it can replace the standard hand on industrial robots already available, giving them a much greater range of dexterity. 

With this increased dexterity, they become more useful in a production environment, handling tasks such as:

  • Pick and Place

  • Component Assembly

  • Machine Tending

Robotic machine tending is an example of how industrial automation is evolving. It refers to the way numerous devices can operate collaboratively. The robot providing the machine tending would typically be responsible for moving an object into a position where the second robot can perform additional operations. 

Machine tending is a role typically carried out by a human operator. As robots become more mobile and dexterous, they are now more able to perform this role. 

For another example of how robots are becoming more anthropomorphic, take a look at David, a robot developed by Institut für Robotik und Mechatronik, or DLR; the German Aerospace Centre. David features 76 brushless DC motors (BLDCs) and 165 position sensors. David has an operating speed that is similar to humans and is categorised as a scientific platform for developing control systems for what DLR refers to as Variable Stiffness Actuators (VSAs). This technology gives David a human look, with a similar size, weight, and mobility range. 

Getting the Best out of Brushless DC Motors (BLDC)

It's interesting to note that even something as advanced as David still relies heavily on standard BLDC technology. BLDC remains one of the most efficient forms of electric motor. What is changing is the way we control BLDCs. 

The trend towards more powerful microcontrollers (MCUs), now commonly aided by digital signal processing (DSP) hardware extensions, means the control algorithms are much more sophisticated. Understanding how to get the most out of these powerful MCUs with DSP can be challenging for embedded engineers unfamiliar with the control systems used with BLDCs. 

Many major semiconductor vendors now offer MCUs targeting BLDC control, along with software development kits that include all of the most popular control techniques. These include Microchip's dsPIC33CH Curiosity Development Board DM330028.  A dual-core Digital Signal Controller (DSC). This crossover device combines MCU and DSP functionality in a single device. 

Trinamic Motion Control (recently acquired by Maxim Integrated) specialises in semiconductor solutions for robotic applications. Its family of TMC5160A motor controllers and drivers integrates a range of features dedicated to motion control, including load-adaptive and load-dependent technologies. 

Rohm Semiconductor also has a strong stepper motor driver portfolio, as does STMicroelectronics with its STSPIN32F0 Advanced BLDC Controllers. 

The next blog in this series will explore the technologies being used by robots to control their position and understand their environment. Meanwhile, why not take a look at Mouser's additional resources to discover more about the world of robotics. 

Read More:

Key Technologies Defining Robotics – From Static Arms to AMRs

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By Mark Patrick

Mark joined Mouser Electronics in July 2014 having previously held senior marketing roles at RS Components. Prior to RS, Mark worked at Texas Instruments in applications support and technical sales roles. He holds a first class Honours Degree in Electronic Engineering from Coventry University.