Robotics in unstructured environments

By Mark Patrick, Mouser Electronics

This article originally appeared in the July'24 magazine issue of Electronic Specifier Design – see ES's Magazine Archives for more featured publications.

Eventually, they become commonplace and even mundane as part of everyday life; historical examples include the motor car, aeroplanes, and mobile phones. 

Robots are another example. Previously used solely in restricted areas that have been guarded for safety, robots have now become more common in environments where people live and work. More of us are becoming comfortable with domestic robots like vacuum cleaners and lawnmowers; we are unfazed working alongside industrial robots in assembly and packing areas, and we can happily coexist with autonomous guided vehicles in factories, farms, and on the streets. 

Robots at home and work

In and around the home, robots are needed as labour-saving devices that can support busy lifestyles. They can help keep tidy outdoor areas that may otherwise suffer neglect, while indoor robots such as vacuums can contribute to a healthier, cleaner environment benefiting from improved hygiene with reduced levels of dust and associated unwanted insects. There are opportunities for further development of new types of robots to help at home. 

In industry, the emphasis is on productivity, taking advantage of robots’ typically higher work rate and repeatability compared to humans. Collaborative robots (cobots) permit optimally blending known robot strengths – such as heavy-lifting capability, endurance, and precision – with human skills like dexterity and decision-making. 

Whereas full automation of a sequence of operations may require complex programming or an expensive custom gripper or handling attachment, combining a robot and human collaboratively can deliver a satisfactory solution faster and more cost-effectively. Moreover, both can be reassigned to other processes easily and at low expense when the factory needs to make changes. 

Crossing the divide 

No longer conceptually confined to restricted areas, robots are entering unstructured environments and taking on a growing diversity of roles, enabled partly by cultural acceptance. Some of today’s literature, TV shows, and films are helping people become more comfortable with the idea of living alongside robots.

And, as an increasing number of households take advantage of domestic robots, the benefits they can offer are becoming more widely appreciated and desired.  

Business owners are persuaded by the economic advantages as equipment vendors offer more diverse ranges including small and even desktop-sized robots and cobots. These can meet the needs and budgets of companies engaged in activities such as electronics manufacturing or lightweight assembly work, food and textiles production, and logistics. 

Robots are no longer perceived only as large, heavy-duty machines for big companies with big factories. Although these types of robots remain, the application landscape has become more nuanced and diverse. 

Transforming technologies 

On the other hand, there are important technological advancements enabling this transformation. They include the latest sensors for motion, proximity, and touch, environmental sensors, as well as 3D imaging, machine vision, radar, and lidar that enable scene analysis and object detection.  

It’s also relatively easy to add geographical location awareness, while precision motor-control IP and robust and efficient power semiconductors are also readily available to assist mobility.  

These enabling factors are needed for robots to function in unstructured environments and to become mobile and collaborative while ensuring the safety of people nearby. It’s critical that they are available within suitably compact form factors and at an economical price. 

Industrial MEMS sensors 

Designers frequently choose micro electromechanical system (MEMS) sensors to provide contextual awareness for robots designed to operate close to people. MEMS sensors are fabricated at the silicon wafer level using processes closely related to those employed for chip fabrication. Sales of MEMS sensors have grown rapidly due to their widespread adoption in smartphones for purposes such as user-interface control, activity tracking, and indoor navigation. 

With integrated signal conditioning, tiny surface-mounted sensors such as 3-axis MEMS accelerometers, magnetometers, and gyroscopes are offered in industrial grades that deliver high precision and often come with extended supply longevity. Manufacturers’ MEMS portfolios also include devices like e-compasses that contain an accelerometer and magnetometer – used in navigation and location-based services – and inertial measurement units (IMU) such as the FSM30x 9-Axis IMU/AHRS module from CEVA, which combines a 3-axis accelerometer, 3-axis gyroscope, and 3-axis magnetometer (Figure 1). 

Figure 1. CEVA FSM30x 9-Axis IMU/AHRS module. (Source: Mouser Electronics) 

Affordable radar 

Advanced system-on-chip integration has enabled miniature millimetre-wave radar sensors to become affordable for cost-sensitive applications. These sensors have proved disruptive in the automotive sector, enabling advanced driver assistance systems (ADAS) to become ubiquitous. By providing accurate object, speed, and distance sensing, they are suited to robotics applications such as industrial autonomous guided vehicles (AGVs) as well as airborne robots, or drones. 

Adding sight for safety 

Several visual sensing technologies are applicable to help robots move around safely in unstructured environments. One such technology is the time-of-flight (ToF) sensor, which emits infrared signals and analyses the returning waves to build a field of view. ToF sensors like the STMicroelectronics VL53L7CX (Figure 2) can be incorporated for diverse tasks such as multi-zone, multi-object distance measurement and 3D scene-mapping using point-cloud techniques. Using several of these multizone sensors to achieve a wide field of view, domestic robots can follow walls, avoid obstacles, map a room, handle hazards such as stairs or ledges, and dock with high accuracy to recharge between tasks. 

Figure 2. STMicroelectronics VL53L7CX ToF multizone ranging sensor. (Source: Mouser Electronics) 

With accurate location technologies and lidar sensors also available, robot designers can consider and combine several different approaches to positioning and guidance to ensure their robots preserve human safety while also avoiding the potential for collisions with other vehicles. 

Conclusion 

With location awareness enabled by sensors for proximity, motion, and positioning, robots are becoming conceptually and literally approachable. Offering advantages such as low power consumption through technological evolution and cost-effectiveness enabled partly by economies of scale, these sensors are helping to make domestic environments more pleasant and industrial activities more productive while preserving human safety.