Category Archives: Robotics

Magnetic Position Sensing in Robots

Robots often operate both autonomously and alongside humans. They greatly benefit the industrial and manufacturing sectors with their accuracy, efficiency, and convenience. By monitoring motor positions at all times, it is possible to maintain not only system control but also prevent unintentional motion, as this can cause system damage or bodily harm.

Such monitoring of motor positioning is possible to implement by contactless angle encoding. It requires a magnet mounted on the motor shaft and provides an input for a magnetic encoder. As dirt and grime do not influence the magnetic field, integrating such an arrangement onto the motor provides a compact solution. As the encoder tracking the rotating magnet provides sinusoidal and 90-degree out-of-phase components, their relationships offer quick calculations of the angular position.

As the magnet rotates on the motor shaft, many magnetic encoding technologies can offer the same end effect. For instance, Hall-effect and magnetoresistance sensors can detect the changing magnetic field. 3D linear Hall effect sensors can help with calculating angular positions, while at the same time, also offering compensations for temperature drift, device sensitivity, offset, and unbalanced input magnitudes.

Apart from signal-chain errors, the rotation of the magnet also depends on mechanical tolerances. This also determines the quality of detection of the magnetic field. A final calibration process is necessary to achieve optimal performance, which means either harmonic approximation or multipoint linearization. With calibration against mechanical error sources, it is possible for magnetic encoding to achieve high accuracy.

The driving motor may connect directly to the load, through a gearbox for increasing the applied torque, through a rack and pinion, or use a belt and screw drive for transferring energy elsewhere. As the motor shaft spins, it transfers the kinetic energy to change the mechanical position somewhere in the system. In each case, the angle of the motor shaft correlates directly to the position of the moving parts of the system. When the turns ratio is different from one, it is also necessary to track the motor rotations.

Sensorless motor controls and stepper motors do not offer feedback for the absolute position. Rather, they offer an estimate of the position on the basis of the relative change from the starting position. When there is a loss of power, it is necessary to determine the actual motor position through alternate means.

Although it is possible to obtain the highest positional accuracy through the use of optical encoders, these often require bulky enclosures for protecting the aperture and sensor from contaminants like dirt and dust. Also, it is necessary to couple the mechanical elements to the motor shaft. If the rotational speed exceeds the mechanical rating of the encoder, it can lead to irreparable damage.

No mechanical coupling is necessary in the case of magnetically sensed technologies like magnetoresistive and Hall-effect sensors, as they use a magnet mounted on the motor shaft. The permanent magnet has a magnetic field that permeates the surrounding area, allowing a wide range of freedom for placing the sensor.

New Requirements for Miniature Motors

Innovations in the field of robotics are resulting in the emergence of smarter and smaller robotic designs. Sensor technologies and vision systems use robotic applications in warehousing, medical, process automation, and security fields. Disruptive technologies are creating newer opportunities for solving unique challenges with miniature motors. These include the robotic market for efficient and safe navigation through warehouses, predictable control of surgical tools, and the necessary endurance for completing lengthy security missions.

With industries transitioning to applications requiring collaborative robotics, they need systems that are more compact, dexterous, and mobile. Tasks that earlier required handling by human hands are driving the need for miniaturized motors for mimicking both the capability and size of the hands that accomplished the work.

For instance, multiple jointed solutions representing the torso, elbow, arm, wrist, etc. require small, power-dense motors for reducing the overall weight and size. Such compact solutions not only improve usability but also improves autonomy and safety, resulting in faster reaction times due to lower inertia. Therefore, robotic grippers, exoskeleton, prosthetic arms, and humanoid robots require small, high-power density motors. Power density is the amount of power a motor generates per unit of its volume. A motor that generates greater amounts of power in a small package, has a higher power density. This is an important factor when there is a space constraint, or where a high level of output is necessary when a limited space.

Manufacturers can miniaturize motors with high power densities. Alternately, they can increase the capability of current designs. Both options are critical in reducing the space that motion elements occupy. High efficiency is necessary to obtain the maximum power possible from a given design. Here, BLDC or brushless DC motors and slot-less motor designs in combination with efficient planetary gearboxes can offer powerful solutions in small packages. Brushless solutions are flexible enough for engineering them to meet customer requirements like long and skinny designs, or short, flat, low-profile configurations.

Smooth operation and dynamic response can result in these miniature motors being dexterous and agile. Slot-less BLDC motors achieve this by eliminating detent torque, thereby providing precise dynamic motion with their lower inertia. Applications requiring high dynamics, such as pick-and-place systems and delta robots, must be able to accelerate/decelerate quickly and constantly. Coreless DC motors and stepper motors with disc magnets are suitable for applications requiring critical characteristics like high acceleration as they have very low inertia.

Ironless brushed DC motors with their high efficiency, are the best choice for battery-powered mobile applications to extend their operational life between charges. Several robotic applications now run on battery power, thereby requiring motors with high efficiency for longer running times. Other applications require high torque at low speeds, and it is possible to achieve this by matching the motor with a high-efficiency gearbox.

Some applications that are inhospitable to humans may need robot systems capable of enduring difficult environmental conditions. This may include tremendous vibration and shock. With proper motor construction, it is possible to improve their reliability and durability when operating under such conditions.

Encoders for Autonomous Mobile Robots

Whether it is AMR or autonomous mobile robots, AGC or automated guided carts, AGV or automated guided vehicles, various types of robots or robotics are increasingly important to the industry. They use these robots to move parts and materials from one place to another in every environment. For instance, goods move from manufacturing to warehouse, and thence to grocery stores to face customers.

It is important that these automated machines work correctly because precision is a vital requirement. This requires reliable motion feedback to the controllers. This is where encoders come in. For instance, autonomous motion applications requiring motion feedback are useful in steering assembly, drive motors, lift controls, and more.

The industry uses several automated carts and vehicles. They use them for lifting products and materials onto and from shelves and floors in warehouses and other storage areas. To do that reliably and repeatedly, these machines require accurate and precise motion feedback. This ensures that materials and products reach where they need to go, without incurring damages.

The Encoder Product Company offers to draw wire solutions, and encoders with rack-and-pinion gears provide reliable motion feedback. This ensures all lifts stop at the right locations, thereby moving materials and products safely to their destinations. Their motion feedback options for lift control involve Model LCX, for high performance with absolute feedback option, and Model TR2, a rack-and-pinion gear as an all-in-one unit.

The Model LCX135 is one of a draw wire series, providing an excellent solution for the control of lifts. Internally, incremental and absolute encoders provide excellent lift control feedback using the CANopen communication protocol.

Automated carts and vehicles require drive motor feedback. As they move around facilities like warehouses, the controller in these vehicles needs reliable motion feedback to ensure the motors are in the proper transit areas/corridors designated for them. The motion feedback also ensures they stop and start accurately.

Motion feedback devices from the Encoder Product Company provide this reliable, repeatable motion feedback. Their Model 15T/H is a compact and high-performance encoder. It is available in the blind-hollow bore or thru-bore designs. The Model 260 is a more economical and compact encoder with a large thru-bore design. The next model 25T/H is a high-performance 2.5” encoder. While Models 25T and 260 are incremental encoders, absolute encoders are also available, and they use the same CANopen communication protocol.

To ensure the correct drive path ad steering angle, the steering assembly also needs to provide precision feedback. Absolute encoders provide the best way to ensure proper motion feedback for these steering assemblies. This is because with absolute encoders it is possible to ensure smart positioning while providing the exact location while in a 360-degree rotation.

The Encoder Product Company offers several absolute encoders. Among them is the Model A36HB, a compact absolute encoder with a 36 mm blind hollow bore. Another is the Model A58HB, an absolute encoder with a 58 mm blind hollow bore.

Where safety is considered paramount, the Encoder Product Company offers redundant encoders. These are simple solutions and economical also. Using redundant encoders allows the application to rely on different technologies, ensuring at least one encoder will continue to function even when the other has failed.

Handling Grippers

Material handling in industries is increasingly relying on grippers. Industries, ranging from automotive assembly to electronics manufacturing, all handle their materials with grippers. The increasing requirement for grippers is evident from the market being worth $100 million in North America alone today, with the number expectedly growing by 5% annually.

The sudden spurt in growth in the use of grippers can be attributed to the rise in robotics. This includes industrial robots taking on special tasks like handling increasingly complex workpieces. Designers now can take their pick from more types of grippers than before. However, even with the latest developments in robotics and gripper technology, picking the most suitable gripper for a specific application can be a daunting task.

The market today has a plethora of grippers including mechanical, adaptive, soft, magnetic, and vacuum types, with each type offering key design features and benefits. For instance, adaptive and soft grippers adapt themselves to the contours of the workpiece and are useful in various handling applications.

Mechanical grippers, both electric and pneumatic types, are popular for handling applications. Of these, the pneumatic types make up about 90% of the demand, as these tend to be lighter and more cost-effective compared to the electrical types. Being more suitable for harsh environments, pneumatic grippers have faster cycle rates and higher grip forces.

On the other hand, electric grippers offer their users better travel and force control along with greater precision. However, the presence of motors and other internal components in these grippers tends to make them heavier and increases their upfront costs.

Irrespective of being pneumatically or electrically operated, there are several design classes of mechanical grippers. For instance, parallel grippers have fingers that can pull directly apart. The most common among these is the two-finger parallel gripper. These make up more than 85% of the market for mechanical grippers. Another version is the three-finger gripper, and it can perform centering functions and handle round objects.

Other classes of mechanical grippers include the angular and radial versions. These typically have fingers that open at an angle. For instance, angular grippers open their fingers only to 30-degrees, while radial grippers can open their fingers up to 180-degrees, allowing them to handle workpieces of varying dimensions while being slower than angular grippers.

Selecting grippers for a specific application requires considering important factors. Depending on the nature of the workpiece, the designer must consider the gripping force required, the guiding strength of the jaw, and the type of the gripper itself. For instance, long gripper fingers require a long lever arm to exert greater torque on the jaws. There are flat finger designs that offer a friction-based grip for durable and bulky parts. On the other hand, handling slippery parts that require precision placement must use encapsulated designs.

Encapsulated designs have fingers with a profile shape matching the object they will handle. Usually, the fingers will be curved to hold a round object. This helps to retain the object in a specific position while preventing that part from dropping if the pressure is lost.

What is Ambient Sensing?

Although smart homes have been around for several years now, this industry is rather nascent. Even though we are familiar with the use of Amazon Alexas and Google Homes as smart devices, but for smart homes, they have their limitations.

Smart devices do use technologies promising levels of interoperability and convenience that were unheard of a few years ago. However, they have not been able to fulfill current expectations. For instance, they struggle if there is no home network, cannot use unprocessed data, and are typically standalone devices.

Movies provide a better concept of a smart home. They present a futuristic building with levels of autonomy and comfort far beyond what the current technology can provide. In the real world, our ability to interact with them is rather limited.

For instance, the smart technology available at present allows interaction with voice commands only, thereby limiting their autonomy. Although the current technology boasts of voice recognition, this is still frustrating and cumbersome to use. Most people seek a seamless experience that comes with higher intuitive or human interaction.

For instance, it is still not possible to unlock a smart home simply by improving voice commands. Although audio sensors do form a crucial element for intuitive interaction with a smart home, making them a part of a sensor array for providing better contextual information would be a better idea. For genuinely smart home, the devices must provide a more meaningful interaction, including superior personalization for contextualized decision-making.

While it may be possible for manufacturers to pack in unique sensor arrays in devices, some sensor types could prove to be more useful. For instance, cameras provide huge amounts of information, and smart systems could make use of this fact to perceive the smart home in a better way. Adding acoustic sensors, and gas sensors along with 3-D mapping could be one way of bringing smart environments to the next level.

By collating these inputs, smart devices can understand and implement individual preferences better. For instance, depending on who has entered or exited the room, a smart device can change the sounds, lights, safety features, and temperature matching that person’s profile. Smart devices must not limit themselves to comprehending the ambient alone, but be capable of changing the environment, even without direct inputs.

These features could go beyond providing comfort alone. For instance, with motion sensors, the device could extend security. Along with motion sensing, individual recognition, and 3-D mapping could make homes much safer. For saving energy, sensors for presence, daylight sensing, and temperature measurements could dim lights or adjust air conditioning for better comfort on hot days.

One of the issues holding back such implementation is consumer privacy. While homeowners have grown accustomed to smart speakers, endless examples are available of data-mining organizations that observe the consumer’s daily interaction with these devices. For instance, Amazon’s Astro robot has been accused of data harvesting and there is criticism of Facebook’s smart glasses by the Data Privacy Commission in Ireland. As devices get smarter and use more ambient technology, consumers will have to share greater amounts of data than they are doing at present.

Developments in Autonomous Robots

The recent COVID pandemic had put a lid on air travel. But that is now slowly lifting, and more people are venturing out. Airports are responding with new robots offering food delivery services.

The International airport in Northern Kentucky is currently using these Ottobots, made by Ottonomy, a robotics company. The Ottobot is a four-wheeled autonomous robot.

At the airport, in the Concourse 8 area, travelers can use a dedicated app to purchase food, beverages, or travel products from select stores. The location of these stores may be anywhere in the airport. Once the travelers have placed their orders, staff, at the store, place the items within the cargo compartment of the Ottobot and send them on their way.

While making its way through the airport, the Ottobot robot uses sensors and a LIDAR module to avoid people and obstacles. Ottonomy has designed a contextual mobility navigation system for the robots to allow them to keep track of their whereabouts. Apart from the contextual mobility navigation system, the robots also use other indoor navigational systems like Bluetooth beacons, readable QR codes, and Wi-Fi signals.

Customers can see the Ottobot on their mobiles, thanks to the app, which alerts them once it reaches their location. The app also has a QR code specific to their order. Once the customer holds their QR code for the robot to scan, it unlocks and opens its cargo compartment lid to allow them to retrieve their purchase. User feedback from a pilot project in the airport helped design the current robotic delivery system.

Not only in airports but there are several urban delivery robots also that use four wheels to move along city sidewalks. The wheels are special, as they can pivot and are mounted on articulated legs.

Delivery robots usually have smart lockable cargo boxes and two sets of powered wheels on their bottom. While autonomously moving along a smooth pathway, this arrangement works fine. However, for moving over curbs, climbing upstairs, or for traversing regular obstacles.

Piezo Sonic, a Japanese robotics company, has developed Mighty, the special delivery robot. They have based their design on a concept for robots exploring the moon:—: it does not have smooth sidewalks.

Mighty has four independently powered wheels. They can point either straight ahead for normal movements, or pivot to point sideways to allow the robot to move sideways in one direction or the other. The four wheels can also pivot part of the way outward or inward, forming a circle for Mighty to spin around on the spot.

Additionally, each wheel has its own hinged leg. Therefore, when the robot moves over an uneven surface, each leg can bend independently to compensate for the difference in height. This helps to keep the main body of the bot level. Mighty can use this feature to climb shallow sets of stairs.

Mighty uses GPS to navigate cities like other delivery robots. It also has cameras and LIDAR sensors for dodging hazards and pedestrians. It can easily carry a 20-kg cargo, climb 15-degree slopes, and step over obstacles up to 15 cm tall, all the while attaining a top speed of 10 km per hour.

A Google Assistant with the Raspberry Pi

This is the age of smart home assistants, but not the human kind. The last couple of years a fever pitch has been building up over these smart home assistants, and every manufacture is now offering their own version. While Apple offers Siri, Amazon presents Echo and Alexa, Microsoft wants us to use Cortana, and Google tempts us with Google Home Assistant, there are several more in the race. However, in this melee, Raspberry Pi (RBPi) enthusiasts can make their own smart speaker using the SBC.

Although you can buy Google Home, the problem is it is not available worldwide. However, it is a simple matter to have the Google Assistant in your living room, provided you have an RBPi3 or an RBPiZ. Just as with any other smart home assistant, your RBPi3 home assistant will let you control any device connected to it, simply with your voice.

The first thing you need to communicate with your assistant is a microphone and a speaker. The May issue MagPi, the official RBPi magazine, had carried a nice speaker set sponsored by Google. However, if you have missed the issue, you can use any speaker and USB microphone combination available. The MagPi offer is an AIY Voice Kit for making your own home assistant. AIY is an acronym coined from AI or Artificial Intelligence, and DIY or DO it Yourself.

The MagPi Kit is a very simple arrangement. The magazine offers a detailed instruction set anyone can follow. If you do not have the magazine, the instructions are available on their AIY projects website. The contents of the kit include Voice HAT PCB for controlling the microphone and switch, a long PCB with two microphones, a switch, a speaker, an LED light, a switch mechanism, a cardboard box for assembling the kit, and cables for connecting everything.

Apart from the kit, you will also require additional hardware such as an RBPi3, a micro SD card for installing the operating system, a screwdriver, and some scotch tape.

After collecting all the parts, start the assembly by connecting the Voice HAT PCB. It controls the microphones and the switch, and you attach it to the RBPi3 or RBPiZ using the two small standoffs. Take care to align the GPIO connectors on the HAT to that on the RBPi, and push them in together to connect.

The combination of the HAT board and RBPi will go into the first box. You will need to fold the box taking care to keep the written words on the outside. Place the speaker inside the box first, taking care to align it to the side with the holes. Now, connect the cables to the Voice HAT, and place the combination inside the box.

Next, assemble the switch and LED, inserting the combination into the box. Take care to connect the cables in proper order according to the instructions. As the last step, use the PCB with the two microphones, and use scotch tape to attach it to the box.

Now flash the SD card with the Voice Kit SD image from the website, and insert it into the RBPi. Initially, you may need to monitor the RBPi with an HDMI cable, a keyboard, and mouse.

Meca500 – The Tiny Six-Axis Robot

Although there are plenty of robots available in the market for a myriad jobs, one of the most compact, and accurate robot is the Meca500. Launched by the Quebec based Mecademic from Montreal, the manufacturers claim it is the smallest, and most precise six-axis industrialist robot arm in the market.

According to Mecademic, users can fit Meca500 easily within an already existing equipment and consider it as an automation component, much simpler than most other industrial robots are. According to the cofounder of Mecademic, Ilian Bonev, the Meca500 is very easy to use and interfaces with the equipment through Ethernet. With a fully integrated control system within its base, users will find the Meca500 more compact than other similar offerings are in the market.

Mecademic has designed, developed, and manufactured several compact and accurate six-axis industrial robot arms on the market. Meca500 is one of their latest products, the first of a new category of small industrial robots, smaller than most others are, and ultra-compact.

The first product from Mecademic was DexTar, an affordable, dual-arm academic robot. DexTar is popular in universities in the USA, France, and Canada. Although Mecademic still produces and supports DexTar on special request, they now focus exclusively on industrial robots, delivering high precision, small robot arms. With their academic origins, Mecademic has retained the predilection of their passion for creativity and innovation, and for sharing their knowledge.

With the production of Meca500, a multipurpose industrial robot, Mecademic has stepped into Industry 4.0, and earned for itself a place in the highly automated and non-standard automated industry. With Meca500, Mecademic offers a robotic system that expands the horizons for additional possibilities of automation, as users can control the robot from their phone or tablet.

This exciting new robotic system from Mecademic, the Meca500 features an extremely small size, only half as small as the size of the smallest industrial robot presently available in the market. Meca500 is very compact, as the controller is integrated within its base and there is no teaching pendant. The precision and path accuracy of the robot is less than 5 microns, and it is capable of doing the most complex tasks with ease.

Applications for Meca500 can only be limited by the users’ imagination. For instance, present applications for the tiny robot include a wide range, such as animal microsurgery, pick and place, testing and inspection, and precision assembly.

Several industry sectors are currently using Meca500. These include entertainment, aeronautics, cosmetics, automotive, pharmaceuticals and health, watchmaking, and electronics. Users can integrate the compact robot within any environment, such as their existing production line or even as stand-alone system in their laboratories.

The new category of robots from Mecademic is already smaller, more compact, and more precise than other robots are in the market. Mecademic’s plans for the future include offering more space saving, more accurate, and easier to integrate industrial robots. They envisage this will enable new applications, new discoveries, new products, new medical treatments, and many more. Their plan is now to build a greater range of compact precision robots while becoming a leading manufacturer of industrial robots.

Robotics and Motion Control

Across the industrial space, automation is a growing trend in factory floors throughout the world. This is essential to improve the efficiency and production rates. When creating the automated factory, engineers may introduce a robotic system or implement a motion control system. Although both can essentially accomplish the same task, they have their own unique setups, motion flexibility, programming options, and economic benefits.

The Basics

A straightforward concept, motion control initiates and controls the movement of a load, thereby performing work. A motion control system is capable of precise control of torque, position, and speed. Motion control systems are typically useful in applications involving rapid start and stop of motion, synchronization of separate elements, or positioning of a product.

Motion control systems involve the prime mover or motor, the drive, and its controller. While the controller plans the trajectory, it sends low-voltage command signals to the drive, which in turn applies the necessary voltage and current to the motor, resulting in the desired motion.

An example of a motion control system is the programmable logic controller (PLC), which is both noise-free and inexpensive. PLCs use the staple form of ladder-logic programming, but the newer models also have human-machine-interface panels. The HMI panels offer visual representations of programming the machine. With PLCs, the industry is able to control logic on machinery along with control of multiple motion-control setups.

Robots are reprogrammable, multifunctional manipulators that can move material, tools, parts, or specialized objects. They can be programmed for variable motion for the benefit of performing a variety of tasks.

Most components making up the motion control system are also a permanent part of robots. For instance, a part of the robot’s makeup includes mechanical links, actuators, and motor speed control. The robot also has a controller, which allows different parts of the robot to operate together with the help of the program code running in the controller. Most modern robots operate on HMI that use operating systems such as Linux. Typical industrial robots take many forms such as parallel picker, SCARA, spherical, cylindrical, Cartesian, or a simple articulated robotic arm.

Robot systems also make use of drives or motors to move links into designated positions. Links form the sections between joints, and robots can use pneumatic, electric, or hydraulic drives to achieve the required movement. A robot receives feedback from the environment from sensors, which collect information and transmit it to the controller.

The Differences

While the robot is an expensive arrangement, a motion control system has components that are modular, and offer greater control over cost. However, motion controller components require individual programming to operate, and that puts a greater knowledge demand on the user.

Motion control systems, being modular, offer the scope to mix and match old hardware with the new. This facilitates multiple setups, with modular configuration ability, and applicable cost constraints.

With hardware differences between products decreasing rapidly, purchasing decisions are now mostly based on the software of the system. For instance, most modern systems are plug-n-play type, and they rely more on their software for compatibility.

How Good are Cobots at Welding?

The manufacturing industry has been using robots widely for several years as a replacement for the human laborer. Recent advances in this field are the Cobots or collaborative robots. They are called collaborative as their design makes them work alongside an individual as a part of a team rather than replacing the humans.

Cobots are good at operations and activities that cannot be fully automated. However, the process speed does not improve for activities such as workers ferrying parts backwards and forwards between themselves on the assembly line with the robots locked away in cages.

Manufacturers such as Ford are already on the cobot bandwagon, and the new robots could transform the way the industry works. The Ford factory has collaborative robots installing shock absorbers on vehicles on the production line along with humans. The cobots work with accuracy and precision, boosting the human productivity, while saving them valuable time and money.

At present, the industry uses four main types of cobots. They are the Safety Monitored Stop, Speed and Separation Monitoring, Hand Guiding, and Power and Force Limiting.

The Safety Monitored Stop is a collaborative feature used when the cobot works on its own, but sometimes needing assistance from an operator. For instance, in an automated assembly process, the worker may need to step in and perform an operation on a part that the cobot is holding. As soon as the cobot senses the presence of the human within its workspace, it will cease all motion until the worker leaves the predetermined safety zone. The cobot resumes its activities only after receiving a signal from its operator.

Speed and Separation Monitoring is similar to the Safety Monitored Stop, with the cobot operating in a predetermined safety zone. However, this cobot’s reaction to humans is different. The Cobot will not automatically stop because of the human presence, but will slow down until its vision detection system informs it of the location of the person or object. The Cobot stops only if the person is within a predetermined area, and waits for the proximity to increase before resuming its operations. This cobot is useful in areas with several workers are present, at it requires far fewer human interventions.

Although a Hand Guiding cobot works just as a regular industrial robot does, it has additional pressure sensors on its arm device. The operator can therefore teach the cobot to hold an object hard enough and to move it fast enough without damaging the object, while securely working with it. Production lines that handle delicate components find Hand Guide cobots very useful for careful assembly.

Power and Force Limiting cobots are among the most worker-friendly machines. They can sense unnatural forces in their path, such as humans or similar objects. Their joints are programmed to stop all movement at such encounters, and even reverse the movement.

As many skilled workers retire, and replacements are rare, the American Welding Society is working with Universal Robots, to produce a new attachment to their UR+ line of cobots with welding capabilities. The robot moves along the start and stop path of the desired weld, and welds only the specified stitch areas.